I loved the explanations on turboprop engines. On a different note: As an Operations officer aboard USS Constellation returning from a Westpac Cruise in 1984 I set up an exercise whereby all the ships of the battle group: destroyers, cruiser, frigates and the oiler lined up moving together side by side at a slow speed and then accelerated on a signal toward smoke float markers put one and five miles ahead. i called it a Rapid Acceleration Combined Exercise (RACE). We were on the way back home and were bored. Constellation took it seriously and they chained a couple of F-14's on the fantail which they fired up and ran at full throttle for the 'race'. As expected, the gas turbine ships did well at first but the CV, with her higher top end, easily was the winner at five miles. Good memories.
Please do more Tomcat stuff. Like you said, lots of small stuff that would benefit from more explanation, like the "glove vanes" or "retractable canards", that only it had but was abandoned to lower operational costs.
@@GregsAirplanesandAutomobiles which is also great! and necessary to be honest - there is not much of this stuff on youtube and some sources are either hard to come by or just hard to read and explain, yet you do a stellar job with regard to simplifying things when necessary but in a way that does not warp the general idea behind those complex processes.
@@GregsAirplanesandAutomobiles a nation can survive foreign enemies but cannot survive treason from within or words to that effect ..Why would the USA(the Australian military /governments destroyed their upgraded F111 fleet) 'governments',military deliberately take out of service essentially its 2 most important air superiority assets ie the Navy F14 and USAF F111s ...thus along with the F35 nonsese handing air superiority over to China,Russia as was always the money power plans ...
You tangent's are more informative than many others main point. Another excellent video Sir, I thank you. I didn't think I would be interested in the F14, between you and Mr Ward Carrol, I have been steeped in F14 all day.
PLEASE do yourself a favor and get a joystick (a cheap used logitech X52 pro will do just fine..... its what i use.... and it has more than enough buttons for the F14) . and then buy DCS f-14 . . yes, i know that 50 to 60 dollars per plane is expensive but you can still fly with // shoot down players who are flying other jets . and the planes WITH OUT clickable cockpits are 10 bucks (f-15, su-25t, su-27, mig 29, ETC) . . . like..... you will spend WAY WAY WAY more time learning, flying, and fighting the 50-60 dollar jets than you will playing ANY new FPS game released today COD/BF can be beat in 20 hours..... Single player AND multi player . but DCS...... you will get 100 hours in, and still be learning new tricks and tips . . . the amount of work and EXACT detail and simulation that goes into these 50/60 dollar jets is just insane you can only pay for what YOU want to fly (again, you can still fly in the same sever with jets you dont own..... on your team or not on your team) . like.... they got the sea level airspeed EXACT on the F-14a its THAT hard core of a simulation . . . . . but if you dont want to learn something for 5 hours before you even know it well enough to take off (let alone land and/or get a radar lock, IFF and shoot missiles) or you dont like waiting 5 mins every time you die for the NAV system to align (plus another 5 to 10 for the engines and systems to boot up) . then DCS is not for you . . but if you LOVE knowing you could LITERALLY jump into a REAL!!!!!!! F-14/FA18/F16/A-10c..... start it up, take off, shoot shit, and land . then DCS is for you . . . . . . also..... dont join multiplayer..... when you dont know how to land... or tell which jets are friendly and enemy on your radar..... the community is AMAZING..... and they will take hours out of their day to teach you . but joining a server as a "noob"..... and team-killing 2 people, before making a crater in the runway because you crashed on landing which means EVERYONE who tries to take off will crash.... due to your aircrafts wreckage and crater . you are GOING to get nasty messages . . . no one wants to wait 10 mins for the NAV to align again...... simply because they got TKed by a dude who didnt use the tutorials or even TRY to learn the jet . . treat it as 80% as serious as real life........ and you will have a VERY fun time and make a TON of friends
also..... but the F-15 first its 10 bucks and will teach you 99% of how to take off/land...... how the radar and IFF works...... how the missiles work.....ETC . and if you decide that you like the game...... THEN pay the 50 or 60 bucks for the "big" jets
From my research, the installed thrust of typical fighters at 0 airspeed is around 80 to 85 percent of the thrust achieved on a test stand. This is due to pumping losses associated with the engine having to pull in air from an aircraft inlet. The curve you saw in aerodynamics for naval aviators represents the theoretical curve for an inlet with 100% efficiency. A good indicator of thrust vs speed is to look for fuel flow graphs in the flight manual.
Surely there must be some ram air effect, especially at supersonic speeds where the air must be slowed to sub sonic intake speeds and hence compressed?
@@gavindavies793 There is massive ram effect with airspeed. The additonal airflow will result in increased fuel flow (thrust) until the fuel system can no longer support the demand, or the inlet can no longer provide slow enough (subsonic) air to the engine.
@@baileyparadis1815 That ram effect overcomes the thrust that would otherwise be lost with increasing speed due to the smaller ratio between inlet and exit velocities. The graph on Page 118 of AFNA illustrates this, and here is some of the text that graph illustrates: The turbojet engine is essentially a thrust producing powerplant and the propulsive power produced is a result of the flight speed. The variation of available thrust with speed is relatively small and the engine output is very nearly constant with flight speed. The momentum change given the engine airflow develops thrust by the following relationship: Ta=Q(V2-V1) Since an increase in flight speed will increase the magnitude of Vi (inlet velocity), a constant thrust will be obtained only if there is an increase in mass flow, Q, or jet velocity, Vs, When at low velocity, an increase in velocity will reduce the velocity change through the engine without a corresponding increase in mass flow and the available thrust will decrease. At higher velocity, the beneficial ram helps to overcome this effect and the available thrust no longer decreases, but increases with speed. The propulsive power available from the turbojet engine is the product of available thrust and velocity. Since the thrust of the turbojet engine is essentially constant with speed, the power available increases almost linearly with speed. In this sense, a turbojet with 5000 Ibs. of thrust available could produce a propulsive power of 3,000 h.p. at 325 knots or 10,000 h.p. at 650 knots. The tremendous propulsive power at high velocities is one of the principal features of the turbojet engine.
As a professional corporate/charter pilot and certifiable crazy person when it comes to airplanes , the Tomcat has always been my favorite when it comes to military aircraft (the F-16 holds a special place from living near Hill AFB all my life as well). That being said, I would love all of the information you would like to share regarding this spectacular aircraft. I will read, watch and study just about anything I can get my hands or eyes on when it comes to flight and aircraft, so as always, thanks for sharing your knowledge. No matter how much we know or might think we know, there is always more to learn on these subjects. Which in turn, makes us better aviators as a whole.
Thank you so much Greg. Your devotion to aviation history and knowledge is incredible. I have always love the history of flight especially WW2 era warplanes. And with your knowledge and easy to understand videos I can truly appreciate the engineering and piloting skill needed to operate these planes. Thank you so much and keep up the Fantastic work.
IIRC, the typical speed at which a jet engine reaches ram air recovery effect is 160 knots. Beyond that speed, ram air is providing increased thrust due to reduced compressor loads and increased internal air pressure supplied to the hot section and power turbine(s). I’m going to have to download a copy of the Aerodynamics handbook to refresh my memory on the subject. Thanks for the video, Greg. Always interested in F-14 videos. Ward Carroll does some very good ones.
My father was a Naval Aviator, a test pilot at Pax River. He took me to an engine test on a F-14A. It was held by two stout anchor chains attached to the main gear. Chains large enough that I had a hard time moving two links. Serous stuff. The ground crew bundled me up in safety gear and then lit the fire. It was the loudest noise I have ever felt. The chief took me aside and asked "Do you know why we didn't take it to Zone 5 (Max A/B)? Because the anchor chains would snap". That was completely inconceivable to me at the time.
@@TurboHappyCar F-14A's launch with full afterburner, both engines, and they stay til they're released, no chains. The chain would not break, the airframe would not break. No guarantee on padeyes in concrete though. It's probably a bad idea because if one engine just shut down, the sudden lack of thrust or tq from one side on the frame could move the aircraft left or right. Maybe. Realistically it's an unnecessary risk and wasteful to spin both up like that. I'd bet there's similar rules for F-15 turns, as well... unless it's only on the Tomcat because of wider engine spacing. F-15 had less problems with flat spins due to engine failure because the engines were closer together.
Greg. I absolutely love your content. Your explanations are so clear and easily understood that it really makes me feel as I have a handle on this subject material. I've been flying planes sporadically since 1998 (still working on my instrument rating) and these videos are just perfect for me. Thank you for doing what you do and and please keep it coming. Jz.
As a retired engineer IMO you are very good at technical explanation. If you ever retire, you should consider teaching the youngsters in technical fields. In my experience very few techies can effectively teach. Your use of piston engine analogies is very effective.
Well done, again, as usual. Even more remarkable, making this kind of content (sort of) understandable to a non-pilot, non-engineer who's mathematically handicapped. For what it's worth, I agree that the F-14 is an interesting aircraft for a variety of reasons. I'm also interested, for obvious reasons, in early jets of the sort that my Dad flew in the late '40s and very early '50s - FH-1 Phantom, F2H Banshee, XF-88 (became the F-101), and the XF-85. Just as in the early 20th century, early jets saw a lot of "make it up as we go along."
I’ve only just started watching and I’m already excited to see the rest! I’ve never really understood the horsepower/thrust thing and 40 seconds in Greg is talking about it! Thanks, Greg.
I always hear that the F-4 Phantom flew like a rocket powered brick. Could you go over her performance and aerodynamics and tell us how extreme it really was?
29,500 ft. time to climb in 60 seconds. Set altitude record at 98,557 ft. Air Force flew to mach 2 on its first flight. Aerodynamics were surprisingly good owing to its area rule fuselage Maneuverability ok due to things like its vari ramp intakes , leading edge slats etc.
I like how you showed several alternate ways to determine power. I calculated based on the mass flow I searched up for the TF30 and came up with a very similar 77173.4 kW, or 103491 horsepower.
Thanks for the great video! I remember quite well when I found out the difference between "thrust" and "horsepower" when flying the 262 in a sim after prolonged periods of 109 and P-51 "driving". I was astonished at what relatively flat an angle one could even outclimb piston powered adversaries, if one was patient enough and let the jet accelerate instead of aggressively pitching for climb like in the prop fighters. Back to the main subject of your video: one could, of course, also argue that the jet is producing horsepower, if one measured the speed difference of the total mass of air going through the engine. After all, it is only the reaction to this process that produces thrust in the first place. 😀 As you already explained, the propulsive horsepower remains zero at standstill. Much like the drivetrain in a drag car not producing propulsive horsepower with the automatic transmission in gear brake and the engine on the two-step (the engine, however, WILL be producing hp).
Thank you Greg. Would love to see a video about the F-14’s glove vanes. Don’t think I’ve ever seen one. Discussing changing center of gravity and center of lift with wing-sweep on the F-14 and other jets would be awesome too. Keep up the great work! 👏👏👏👍
Not an engineer here, but i have been running some flight model experiments back in the day, regarding the F-14A and D for an old flight simulator i will not name here, as a part of a modding community for that simulator. When retaining the aerodynamic properties from the wing tunnel tests, having the thrust set to 17-18000pds per engine gave performance that matched the performance manuals much closer then the 20000+ pounds per engine. Of course, a lot of this may have to do with simulation-engine specific factors, but if we take into account that the same engine was used with the other lookup tables, then i think it's pretty safe to assume the installed engine was inside the 17-18 kpds category.
Dear Greg, Thanks so much for the effort and thought you put into these videos. I hope you and your family have a happy and healthy holiday season and a prosperous new year.
It would be interesting to hear about the horsepower that VTOL planes produce, while taking off vertically. Hope to see videos about the Hawker Harrier and especially Yak-38 and Yak-141 one day.
I second this, as well as the opposite (how do you figure how much thrust a prop plane has when stopped?). Something I've always wondered and could be interesting to discuss.
Propeller aircraft is measured in SHP via the twist in the torquemeter shaft. How much force it takes to twist a shaft. Thats the way is measured on the c130j, i guess it is the same with the osprey and other propeller aircraft.
@@fsendventd You could chain it down with a big spring scale in the chains (these days you would use a load cell) and crank it up to see the maximum reading you could get on the scale. This would actually be useful information to know for, say, a carrier launch.
Thank you, Greg, I learned a lot today. Not only their benefits, shortcomings,, advasntages, disadvantages in full detail, Finally someone explained the differences between them and why turboprops are used on some aircraft types almost exclusively, until now, I have never been able to understand them.. :D
Witnessed an F14 take off twice in my life, Wings over Houston in the 90s and Texas Air National Guard I think. Those unrestricted day. It was the LOUDEST plane I ever saw , flew off, climbed and did 90 degrees ... ! The year after there was an issue and it returned to field. An Awesome plane !
@@TurboHappyCar well, we could try to beat all by getting my work's museum collection to fire up one of their Walter rockets from the Me163 Komet , but I don't think they'd have enough stof lying around lol
Wow I was just reading through this chapter at work and in my spare time (scientist by day with a CPL) on my Kindle. I have found that it's very enlightening even after doing my CPL well worth the read if you can get through how dry it is. Personally I would love more Turbine and jet engine content really liked your video on the pull start Jumo engine.
MORE JET AGE stuff would be perfect. I am saving this video so i can watch it again to get a even better grasp on the concept of thrust and horsepower.
Thanks for the wonderful content, Greg! I cannot express just how satisfying it is listening to you explaining these concepts in meticulous detail but magically lightly. And every time I might feel left hanging for some detail, you feed me that nugget just before I lose hope. I really appreciate also how you do your utmost to stay credible at all times and this is not necessarily the only way to make videos, but it is a good way and I like how you do it. Please keep it up! and I for one would love that F-14 video as well as other jet-era aircraft.
The history and design of its flight computer is interesting, by martin marietta if not mistaken. It was a custom processor, to drive the wings angle automaticaly. Unique or rare, most planes with variable geometry where limited to set angles.
Once I sat in a cube next to a guy who wrote some of the F-14 code. He had worked on other planes too. He said that the F-14 was the most carefully engineered of them all.
Hey Greg, it is happening! I just read an article about peoples insurance increasing in price, and the people couldn't figure out why. Turns out the car manufacturers are selling your data to insurance companies so that they can see how you're driving!!! INCREDIBLE!!! I will not buy a new car for this reason! I think this is absolutely wrong!!! The whole purpose of buying a car like a Mustang is to have fun!! I have had several Mustangs in my life they were all 5.0s. They were very fast, and I had a lot of fun driving them on the highway on my to work ! I took full advantage of their great performance, and when I got into the city, I could really go nuts, fishtailing, and slamming gears because there are hardly any cops around. The manual trans on my 89 GT was Bullet proof! The rear even had an extra set of shock absorbers mounted horizontally to keep the wheels from slamming into the wheel wells! What I'm saying is why would I buy a new Mustang when Ford or whoever is going to tell on me and cause my insurance to go up?? I have a good driving record, and I always would make sure it was safe when I messed around. I wouldn't put other people in danger or smash up my car. The car manufacturers are going to lose business when people find out about this. Especially mucsal cars or sports cars! Somebody will figure out a way to disable this feature. They always do. Car manufacturers have no right to be spying on you like that!! I see lots of lawsuits when people figure this out coming on the horizon or people insisting on a law against this if there isn't one already. I think I would rather put the money into restoring my 1998 Lexus LS 400. Yes, I have mellowed out in my old age. The car is 26 years old and it's my daily driver! Lexus went all out building this car because it is the first model they sold when the company started. They wanted to beat Mercedes and BMW, so they used top notch materials and design. The V8 engine is an incredible design. I believe it's even used in airplanes. It gives that big car a zero to sixty in 6 seconds. Not bad for back in the day!
I love your tangents.. I already understand all the physics but I still love listening to this content.. All the little details, stories from the real world...
Would love to hear about the F-14A's high speed performance vs the B model. Heard someone did Mach 2.6-2.7 and had to reduce the throttle because the glass was getting too hot, or something similar.
That’s just rumours. The fastest the F-14 ever went was 2.34 Mach in early testing. As for the B model the F110s actually work in a different way to the TF30. To generate more thrust the GE pushes more air. The PW gets hotter. Thus at high altitude the TF30 actually produced more thrust but was less efficient. With the thin air the F110 doesn’t have as much air to push. The F-14D can’t actually make 2.0 because it doesn’t have the extendable glove vanes at all. Without them no F-14 can get past 2.0 Mach. The glove vanes bring the centre of pressure of the jet back within limits at high speed. Otherwise it creeps back and creates a nose down pitching moment. This increases the speed and pushes the centre of pressure further back and the jet enters an unrecoverable dive. All A and B models had the glove vanes welded shut. Sorry to be a party pooper but no Tomcat ever got past 2.34 Mach.
@@dat581 That is exactly why I'd like Greg to dive into it in more detail, pull research documentation and see what the test pilots had to say. It would be interesting to see if the Tomcat with TF-30's could actually overspeed like that. What would be really interesting (I'm just dreaming) is to see a Tomcat with technology the SR-71's engines used to make it mach 3+. Who knows how it works handle high AoA, though. Would love to see a huge thrust F-14 with a big AESA radar, stealth considerations, potential mach 3+, yadda yadda. One can dream....
@@speedycpu The F-14 is never going to stay above 2.3 for long without melting. The TF-30s have been proven to 2.5 in the F-111 and they are essentially the same engine with different nozzles. The F-111, which is a slicker airframe than the F-14, would only get to 2.5 when clean and with the engines in very good condition. A timer starts above 2.0 and the jet has a limited time before it melts. The F-14 is made from similar materials. As for the SR-71 engines that would be pointless for several reasons. The primary reason is the F-14 rarely got above 1.4 in service. It was actually limited to 2.0 by the Navy. The ramjet is also not suitable for a fighter at all. Most people would be surprised how much of a dog the SR-71 was until it got up to cruising speed. Most fighters could easily out accelerate it. People love to quote the top speeds of jets but they are actually one of the more irrelevant statistics in service. The F-35 is limited to 1.6 Mach because that’s what the USAF wanted. The jet has the aerodynamics and thrust to easily make 2.0 but it would need new intakes. The reality of fighters is quite a bit different to how they are portrayed as you can tell from Greg’s videos!
@@dat581 I read the SR climbed out at 400+ so thats impressive . Thats not the first time I've heard of F14 glove vanes shifting lift . A poster on a vlog who sounded legit'ish (said he was a military pilot or something) stated the F35 WITH STORES under the wings will out accelerate a clean F16 when ask about F35 performance . Now it there is any truth to that Fat Amy is maybe not so fat . I know it has the most powerful engine but a clean viper is a rocket .
At an airshow quite a long time ago saw an F-14 performing together with an aerobatic prop driven bi-plane. They did a number of loops with both tangent and coincident at the bottom of each loop. The F-14's loop was bigger, guessing from memory between 5 and 10 times as big. Impressive management of both airplanes.
Nice video! One thing I would like to comment on. That 325 number is important as in terms of Knots, this equates to 370 mph ( APPROX ) which as it turns out is the begining of the middle flight regiem ( subsonic, transsonic, supersonic ). For those who do not know this is the velocity where the air cannot get out of the way of the object moving thru it and starts to compress. It is my understanding that this is why prop drive A/C have a hard time getting above 400 mph. The prop, wing and fusalage all compressing air starts to use up HP very quickly. As a former, now retired, industrial air compressor tech, I can tell you compressing air requires lots of grunt ( HP ) and generats lots of heat. Using flooded screw type of compressors some industries, my case sawmills, can heat large parts of the mill using a well designed heat exchange system. A 200 hp compressor can generate 80 to 100 BTUs. Looking at an axial compressor, turbojet or turboprop, with a multiple turbine set up one stage or more will be used just to run the compressor(s)/fans. The difference between an electric and internal combustion engine driven compressor efficency is around 2 to 2.5 : 1 in the electrics favour. So using your formula, a Boeing Dreanliner using the latest 110K lb thrust engines will generate a theoretical value of 350 to 400K hp. Nice considering a Gerald Ford class aircraft carrier generates about the same. That 370 mph thing, I did a quick check of hp vs speed on a couple of WW ll a/c Spitfire snd Mustang, A thru ??? models and this idea holds up. I have not done this with any other a/c, P38, P47, F4U etc.
I think also the reason why jet can accelerate a flying object past this compresssibilty barrier is that the trust it creates is made of very high velocity air mass compared to propeller. The impact of say 300 kts of airstream created by forward speed compared to the exhaust air speed of the jet engine is far less than the same speed with a propeller aircraft. BTW propeller is kind of the same as a jet if you think about creating trust by way of accelerating an air mass (be it behind a propeller or a trust tube) Also this is why modern airliners cannot fly as fast as early jet airliners, because modern airliners jet engines became more and more like propeller engines (fan up-front) and less jet engines (simple core jet) and their exhaust velocity is thus far less. They are optimized for the speed they operate at.
Thanks Greg! It's kind of interesting that while I was doing some work at Mt. Storm Power Station in West Virginia, I got to see some Tomcats flying through the nearby valley at speed. I was not more than a few hundred feet away, and 50 to 100 feet above them, so I could see right into the cockpit - it was pretty cool.
Great video. Started watching a few days ago while watching dishes but paused until I could really pay attention. I will definitely share with my colleagues who are interested in not just planes but engineering in general. I didn't used to be a big fan of the F-14. Probably because during my time at the AF academy all my classmates who wanted to be pilots would quote Top Gun non stop :(. Looking back it does appear to be an interesting plane and I would love to see more Tomcat stuff!
I greatly appreciate this video, Greg. I was just looking into thrust/hp-kw conversion and Google was useless. I can’t wait to see you cover the Tempest. It’s an aircraft I should have known about decades ago, but only learned of its existence recently. Those WWII panels would make one hell of a cool sim setup!
I thought that you also were going to compare fuel flow which could also be shown in horsepower, so I did the calculations myself. Sticking to the F1 grid analogy - a single F14A with afterburner consumes about 922 000 horsepower in fuel, a modern F1 engine is limited to about 1676 horsepower in fuel due to maximum fuel flow restrictions, so if my calculations are correct and estimations are not that far off then it means that a single F14A consumes as much as 27.5 full F1 grids worth of "fuel horsepower". P.S. Keep up the good job, I really love your videos!
Greg, you need to contact Ward Carroll. He has a channel on RUclips and was an F-14 pilot when he was in the US Navy. His channel is interesting. I watch it, as I watch yours and Military Aviation History on a regular basis. If anyone can give correct info on the Tomcat, it's Ward.
He was a RIO, not a pilot, but that doesn‘t in any way detract from his superb channel. It’s a must for anyone interested in the F-14 or naval aviation.
All this stuff is way above my head but as usual, you explained it in a way everyone can understand the concepts and principles. Plus, you picked a great aircraft to help illustrate it.👍
@@GregsAirplanesandAutomobiles haha I can always guarantee when you make a disclaimer regarding the technicality of a video, it's going to be a good one!
I like the "pushing the car with the handbrake on" analogy. I was thinking of the difference between a motorcycle using it's engine to spin the wheels versus someone with a big wrench applying a torque to the wheel.
Yes, the person with the wrench may be able to apply just as much torque as the engine, but will not be able to apply that much torque AND spin the wheel at high RPM.
I think some confusion comes from the way we say the engine "has" horsepower as if it's an intrinsic property, when really horsepower is a result. An IC engine appears to have intrinsic horsepower because the way horsepower is defined for an IC engine is linked directly to the mechanical function, so it can't avoid producing horsepower while in operation. The way power is defined in a jet is decoupled from the operation of the engine.
@Kirk Wolfe what I mean is that the power of a piston engine is directly related to the torque and rpm of the engine itself, but the power of a jet is related to the thrust of the engine but the speed of the whole vehicle, not the rpm of the turbine.
@@andrewdynes5300 I am not arguing that there is no way to measure power from the jet engine itself. I am saying that it is confusing to people because of the way power is defined and measured in IC vs jets. Piston engines appear to have intrinsic power because of the way bhp is defined and measured, so people assume jets do as well. But as we see in the video, it's all about how you define power.
Thanks Greg! Your channel, along with AgentJayZ and Blancoliro fulfill my aviation geek needs! Many hours of AgentJayZ prepared me to understand this video.
If you have any interest in machining and the like you might also take a look at 'Rotary SMP'. He is an aircraft mechanic by trade, and always manages to spend a couple of minutes on some aside that is aircraft engine related in his videos. The most recent one spent a couple minutes showing the attachment methods for an airliner jet engine.
Great video, Greg. This video should have been titled "How Horsepower works, using F-14 as an example" I learned more basics of thrust/horsepower/torque/etc than I did about the F-14, thanks! Also, your bit on turboprops was spot on. I believe the Saab uses it's port engine as an APU by inserting a locking lug into the gearbox, so the turbine will generate power for the accessory gearbox, but the prop won't turn. I've got plenty of time in the C208 and it was great holding 170knots to short final. Very quick aircraft for short flights.
Hi Raptor. In the second paragraph of the description, I make it clear that this video is intended to convey certain concepts using the F-14 as an example and not really an F-14 video. Of course I also answer the question posed in the thumbnail inside of the 30 second mark, so I think I'm good there. Great point about the Saab. The Cessna 208 is indeed great at holding that speed until the last moment, it's a wonderful airplane.
The nuclear powered scramjet built for project pluto cruise missile (more like a flying locomotive) was tested at full power for 20 minutes and put out power equivalent to 250,000hp and would have flown at Mach 3.5 at tree top height.........its shock wave killing people on the ground let alone the nuclear fall out in the exhaust. The engine could travel from the USA to the USSR and still have plenty of fissile fuel to circle the USSR polluting it without fallout in addition to its magazine of multi megaton H-bombs. Stanley Hooker in his book regarding jet engines, placed emphasis on the improvement of compression ratios inside jet engines to denote their improved efficiency..........compression is key to getting the fuel to provide more effort per unit of fuel. Always interesting videos, thanks again Greg.
Greg, The graphic with the horse at the beginning of this video summarizes the classical relationship between force, work, and power. A force measured in ‘pounds force’ can also be termed thrust in the aircraft world. Work is force applied to an object to move it. Work = force x distance; measured in foot-pounds Power is the measurement of work per unit of time. Power is the rate that the work is done. A force applied to an object that does not move does no work. Work requires movement. Without work, power is zero.
F-86 > Mig 15 Because; All-flying stabilizer. The Russians obviously read NACAs research reports from the early 1940s on streamlined bodies with internal flow. Because they ended up making a nearly identical aircraft to the Saber, while they obviously missed several key advances that were unpublished and kept top secret between the reports they had access to and the launch of the F-86.
@@Triple_J.1 Even with the flying tail, the MiG still had an edge in maneuverability. It also had a higher ceiling and climb rate allowing it to pick its fights. The two aircraft were almost a match speed wise, though the F86 was slightly faster. The F-86 had a much weaker gun package (the USAF was still fixated on the.50 cal). However though the 23mm/37mm cannon mix on the MiG gave dispersion issues, any hit on a Sabre was bad news (some 20mm cannon armed Sabres were tested in Korea with very good results). What really gave the Sabre an edge, was the radar assisted gun sight (which the Soviets quickly copied from downed Sabres).
Excellent topic Greg. I am a fellow airline pilot, E190 and CRJ type rated Capt, never been in the military aviation but it has been a life long passion and especially naval aviation regardless of the nationality. There is a characteristic of the F-14 that would be interesting if you dig into and that is the rocking motion on the longitudinal axis at high AoA esp at high G. Many planes show this tendency but it seems more pronounced on the F-14. Thanks and keep theses awasome vids comming!💪🏻
That would be an interesting video. However if I make another video featuring the Tomcat I'm going to start with something related to the propulsion or electrical systems.
I know that you focus mostly on fighters, but I'd personally be interested is seeing a little expansion on this subject. You mentioned the turboprops, and turbojets in terms of there efficiencies, and advantages at their respective operational speeds. Might be interesting to throw turbo fans into that mix as well. In truth; some of the most powerful jets out there are turbofans, and they have a relitivly wide operational speed range falling in between the turboprop, and turbojet. If a fighter must be used as a starting point; Saab Viggen did use a turbofan. ; )
Hi Central, good points. The Viggen uses a Volvo turbofan which is basically a Pratt and Whitney JT8D with the addition of an afterburner. I have a lot of time flying the JT8Ds in 727s. It's a very low bypass turbofan, at least low bypass by modern standards. I probably should cover turbofans as they are the standard type of jet these days for anything subsonic. Even the newer fighters have turbofans, although low bypass and with afterburner.
@@GregsAirplanesandAutomobiles I have a theory that the whole conspiracy concerning vapor streaks in the sky springs from the operation and increased efficiency of these engines. SMH
@@sadwingsraging3044 Contrails (condensation trails), as we used to know them, will occur with piston engine propeller aircraft. They aren't a direct function of jet engines as many people seem to believe. They were a big problem for the 8th Air Force when doing bomb runs over Germany in B17s in the 1940s, because the whole formation would have contrails pointing to the planes, giving the Flak gunners a hint of where to aim.
@@lwilton I was intentionally being vague with my wording. Didn't want to awaken the algorithm beast. You never know what the flighty thing will be displeased about and take it out on Greg's channel. Unless I am wrong these new ultra modern engines are in effect nothing more than high efficiency highly highly HIGHLY modified shrouded props with maybe a little fuel tossed in somewhere for expansion and keep the whole thing spinning at the same time. Just an observation I have thought about occasionally.
You touched on the topic when comparing turboprops and generic jets. Turboprop thrust is maximized to move a large mass of air. A turbojet (particularly afterburning jets) maximize pressure of air (low pressure in, high pressure out). Fanjets and the new Geared fanjets are trying to be turboprops (maximum airflow), with a very slight increase in pressure.
Thank you for another great video Greg. It's not something I've been thinking about, but I did wonder were the conversion number came from during AME school.
Hi Greg, Confused thinking, and vaguely remembered high school physics lessons led me to ask the question. I went back and thought about it again. The exhaust gasses have mass and velocity, that is momentum, which cannot be tied to horsepower. I suppose that if the velocity of the mass of air entering the combustion chamber could be measured against its velocity on exiting the turbine, then the work done in accelerating that mass air could be calculated and hence horsepower. But, that is another rabbit hole! All the best!
When i was young it took me awhile to understand the difference between torque and hp and in retrospect, most explanations were just bad. You're explanation of this similar concept was well done. I think boiled down to its simplest form, the difference is that Torque and thrust are measures of force while hp is a measure of work.
The statement that "it moves air, therefore it has horsepower" is actually true. To generate the high speed flow out of the engine, the exhaust gas flow undergoes a change in specific enthalpy in the nozzle and this change multiplied with the mass flow of air equals a power figure. Expressed as a different but equally true concept, you have to apply a force to accelerate the exhaust flow and that flow has velocity, therefore there is power being generated in the engine. The ratio of this internal power compared to the propulsive power is the propulsive efficiency of the engine, analogous to the propeller efficiency line in the charts turboprop charts you showed. The only important power number for performance calculations is the propulsive power though.
I'm not sure if you watched the entire video before commenting, but what you said is more or less what I was saying in the video. Sure it makes horsepower when stationary, but not propulsive horsepower. Engines are rated in horsepower which can be used for work, not just the power needed to spin itself. In other words, when we say "horsepower" we are normally talking about propulsive horsepower.
Greg, if you aren't already aware of him, check out Ward Carroll's channel. He was a Tomcat RIO and I believe later a pilot. He has done a number of videos on many aspects of the Tomcat and rundowns of actual missions. His videos are often very detailed like yours. I'm sure he could either answer many questions or point you in the right direction, not that you seem to have much trouble with research, and could no doubt offer many real world "When you do that, this is what happens" type of stories.
I love your compendious videos! Surely the (empirically determined) maximum rate of climb is the ultimate measure of the power of an aircraft. I remember that my 5th grade (or was it sixth? ca. 1968-69) teacher got us to recognize the difference between force and power by getting some of the (most self-important) students to take up opposing positions on his desk and push for all they were worth. Of course the desk did not move and he declared that despite all the force exerted, the amount of work achieved was zero. As to the Tomcat, using an empty weight of 20 tonnes, and published rate of climb of 230 m/s, yields a horsepower of about 60,000. Ludicrous!
I always remind myself that one of the kinds of turboprops are just tiny turbojets with a propeller bolted to the front and that the other kind is sort of a gas turbine driving a propeller with it's exhaust gases. It's probably not completely true, but it does give me a great picture in my head and it seems to stick in my brain.
If I recall correctly some of the wheel-driven land speed record cars turned surplus military jet engines into something akin to the free shaft turbo-prop you showed, by directing the unmodified jet's exhaust into a separate turbine to drive the wheels.
Thanks for the deep dive Greg. Always a treat. Can you in the future look at why I have always read the A was under powered compared to it's contemporaries and the latter B/D models?
Greg, when you were talking about BSFC (brake specific fuel consumption), it actually should have been BTE brake thermal efficiency). For BSFC a smaller number is better as in less lbs of fuel to produce a given amount of power. BTE is the ratio of output power divided by the fuels energy for a given quantity of time.
Not sure if it was covered in the comments already but the issue with power and thrust has always been a problem for engineers that missed that day in physics class. Energy, Work, Power, Force.... energy is the capacity to do work, work is force times distance (also torque times RPM in angular systems), force also has a distance element (mass x distance), and propulsive force has the thrust and velocity elements. So I can use all my energy to the peak of my power and push against a brick wall, but unless I move the wall, there is zero work and zero force. Along the same premise using a small scale experiment, I can spin a 24x12 propeller to 7100 RPM and develop 47 pounds of thrust with 8 HP at the shaft (ESHP). Using the same 8 HP, I can also spin a 29x12 to 5490 RPM and develop 54 pounds of thrust. Of course, the 12 pitch to 7100 RPM may result in a higher pitch speed, but the 7 more pounds of thrust from the 29x12 will result in better and instance accelerate.
Interestingly, Agent Jay Z channel argues the power statement on a rested plane, citing the mass flow displacement. If you look it from another perspective, if you put a plate behind a non moving tomcat at full afterburner and the plane can be moved forcing resisting hydraulic pistons for example, you might find that work has been done. However since you don’t see anything if there is no visible solid barrier, displacement of air molecules is not considered work. It is worth thinking about it IMHO.
I have thought about it. I'm not sure what Agent J is saying (I don't know him), but AFNA is clear on this point and the physics of aircraft climb performance back it up 100 percent. If he is saying that with zero forward motion a jet engine is producing propulsive horsepower, then he is simply wrong.
@@GregsAirplanesandAutomobiles It is theoretical. Horsepower is measured where there is movement, for example the flywheel. Sure, but there is movement at the turbine wheel at the jet plane as well. If there were a device to measure it, there would've been some horsepower. However, AFNA uses theoretical conclusions to explain /and help with calculate/ some of the events in flight. It is pretty much like MAC. MAC is mostly theoretical, since there is no rectangular wing with such shape with which you get your measurements for WnB settings, however you use MAC when you set up your Beoing jet. Again, MAC is theoretical and only theoretical. I am not insisting on this, but it seems more logical than in the AFNA - > if there is a mass flow movement, then work has been done, then HP can be theoretically measured. Jet engines used to produce power on other applications than jets have that measurement. Semantics. Maybe its worth taking a look: ruclips.net/video/40OV47wee7o/видео.html
Damn. As much as I appreciate the F-14, after Greg's last video, I was hoping for a continuation of the P-40 Warhawk (similar to his series on the P-47 or FW-190). Still, thank you, Greg. Love all your videos.
Hey Greg, you have a really intuitive understanding of propulsion systems, could you in the future make a video comparing and contrasting piston, turbo fan, turbo prop, and turbo jet engines? Or even a video comparing the benefits and drawbacks of the different piston configurations such as inline, opposed, v, and radial? Forgive me if you have previous videos on the subjects, I just discovered your channel today!
Thanks for visiting my channel. I'll do exactly that. I have never talked about turbo fans in detail and a lot of people are asking for that. I do have some videos about jets, and of course a lot about piston engines.
I remember that when I was a wee lad (9?) my dad went off ranting if I happened to ask about the horsepower of a Viggen or such (he was an engine engineer for SAAB).
The F-14A is my all time favorite Cold War-era jet. On paper, it's rather lackluster (compressor stall complaints aside) but in actual practice, it's quite a maneuverable aircraft despite its power deficiency once again on paper. What I would like to see someday is some information on how the Tomcat did in combat during the Iran-Iraq War since that's where it enjoyed the majority of its success.
Agreed-the main issue with the TF30 powered F-14A was not necessarily its thrust to weight ratio but rather the engines poor stall margin. Most pilots that flew the F-14A felt that given its fuselage and wing design that the TF30 provided adequate thrust. The reliability of the TF30 in air combat maneuvering though was another matter. Despite the increase in thrust that the F-110 engines offered in the F-14B & D variants. The F-14A with the TF30’s could still out perform them in certain high speed regimes of the flight envelope. There was a phenomenon called a “ram effect” that benefited the TF30 in that scenario. I would love to hear an informed explanation regarding this.
I loved the explanations on turboprop engines. On a different note: As an Operations officer aboard USS Constellation returning from a Westpac Cruise in 1984 I set up an exercise whereby all the ships of the battle group: destroyers, cruiser, frigates and the oiler lined up moving together side by side at a slow speed and then accelerated on a signal toward smoke float markers put one and five miles ahead. i called it a Rapid Acceleration Combined Exercise (RACE). We were on the way back home and were bored. Constellation took it seriously and they chained a couple of F-14's on the fantail which they fired up and ran at full throttle for the 'race'. As expected, the gas turbine ships did well at first but the CV, with her higher top end, easily was the winner at five miles. Good memories.
That's one of the coolest stories I have ever heard.
Please do more Tomcat stuff. Like you said, lots of small stuff that would benefit from more explanation, like the "glove vanes" or "retractable canards", that only it had but was abandoned to lower operational costs.
What i hear they help with the transonic region of flight
I love these types of contents, as an engineering student, keep doing great
This video is for you engineering types. Not much history in this one, mostly just technical stuff.
@@GregsAirplanesandAutomobiles which is also great! and necessary to be honest - there is not much of this stuff on youtube and some sources are either hard to come by or just hard to read and explain, yet you do a stellar job with regard to simplifying things when necessary but in a way that does not warp the general idea behind those complex processes.
@@GregsAirplanesandAutomobiles a nation can survive foreign enemies but cannot survive treason from within or words to that effect ..Why would the USA(the Australian military /governments destroyed their upgraded F111 fleet) 'governments',military deliberately take out of service essentially its 2 most important air superiority assets ie the Navy F14 and USAF F111s ...thus along with the F35 nonsese handing air superiority over to China,Russia as was always the money power plans ...
You tangent's are more informative than many others main point. Another excellent video Sir, I thank you. I didn't think I would be interested in the F14, between you and Mr Ward Carrol, I have been steeped in F14 all day.
Thanks, and I like Mr. Ward Carrol's channel as well.
PLEASE do yourself a favor and get a joystick (a cheap used logitech X52 pro will do just fine..... its what i use.... and it has more than enough buttons for the F14)
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and then buy DCS f-14
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yes, i know that 50 to 60 dollars per plane is expensive
but you can still fly with // shoot down players who are flying other jets
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and the planes WITH OUT clickable cockpits are 10 bucks (f-15, su-25t, su-27, mig 29, ETC)
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like..... you will spend WAY WAY WAY more time learning, flying, and fighting the 50-60 dollar jets than you will playing ANY new FPS game released today
COD/BF can be beat in 20 hours..... Single player AND multi player
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but DCS...... you will get 100 hours in, and still be learning new tricks and tips
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the amount of work and EXACT detail and simulation that goes into these 50/60 dollar jets is just insane
you can only pay for what YOU want to fly (again, you can still fly in the same sever with jets you dont own..... on your team or not on your team)
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like.... they got the sea level airspeed EXACT on the F-14a
its THAT hard core of a simulation
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but if you dont want to learn something for 5 hours before you even know it well enough to take off (let alone land and/or get a radar lock, IFF and shoot missiles)
or you dont like waiting 5 mins every time you die for the NAV system to align (plus another 5 to 10 for the engines and systems to boot up)
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then DCS is not for you
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but if you LOVE knowing you could LITERALLY jump into a REAL!!!!!!! F-14/FA18/F16/A-10c.....
start it up, take off, shoot shit, and land
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then DCS is for you
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also..... dont join multiplayer..... when you dont know how to land... or tell which jets are friendly and enemy on your radar.....
the community is AMAZING..... and they will take hours out of their day to teach you
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but joining a server as a "noob"..... and team-killing 2 people, before making a crater in the runway because you crashed on landing
which means EVERYONE who tries to take off will crash.... due to your aircrafts wreckage and crater
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you are GOING to get nasty messages
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no one wants to wait 10 mins for the NAV to align again...... simply because they got TKed by a dude who didnt use the tutorials or even TRY to learn the jet
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treat it as 80% as serious as real life........ and you will have a VERY fun time
and make a TON of friends
also..... but the F-15 first
its 10 bucks and will teach you 99% of how to take off/land...... how the radar and IFF works...... how the missiles work.....ETC
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and if you decide that you like the game...... THEN pay the 50 or 60 bucks for the "big" jets
From my research, the installed thrust of typical fighters at 0 airspeed is around 80 to 85 percent of the thrust achieved on a test stand. This is due to pumping losses associated with the engine having to pull in air from an aircraft inlet. The curve you saw in aerodynamics for naval aviators represents the theoretical curve for an inlet with 100% efficiency. A good indicator of thrust vs speed is to look for fuel flow graphs in the flight manual.
Can depend quite a lot on inlet design. An F-16 gets like 10-15% more static thrust from its F-100 than an F-15
Surely there must be some ram air effect, especially at supersonic speeds where the air must be slowed to sub sonic intake speeds and hence compressed?
@@gavindavies793 There is massive ram effect with airspeed. The additonal airflow will result in increased fuel flow (thrust) until the fuel system can no longer support the demand, or the inlet can no longer provide slow enough (subsonic) air to the engine.
@@baileyparadis1815 That ram effect overcomes the thrust that would otherwise be lost with increasing speed due to the smaller ratio between inlet and exit velocities. The graph on Page 118 of AFNA illustrates this, and here is some of the text that graph illustrates:
The turbojet engine is essentially a thrust producing
powerplant and the propulsive
power produced is a result of the flight speed.
The variation of available thrust with speed is
relatively small and the engine output is very
nearly constant with flight speed. The momentum
change given the engine airflow develops
thrust by the following relationship: Ta=Q(V2-V1)
Since an increase in flight speed will increase
the magnitude of Vi (inlet velocity), a constant thrust will be
obtained only if there is an increase in mass
flow, Q, or jet velocity, Vs, When at low
velocity, an increase in velocity will reduce
the velocity change through the engine without
a corresponding increase in mass flow and
the available thrust will decrease. At higher
velocity, the beneficial ram helps to overcome
this effect and the available thrust no longer
decreases, but increases with speed.
The propulsive power available from the
turbojet engine is the product of available
thrust and velocity.
Since the thrust of the turbojet
engine is essentially constant with speed, the
power available increases almost linearly with
speed. In this sense, a turbojet with 5000 Ibs.
of thrust available could produce a propulsive
power of 3,000 h.p. at 325 knots or 10,000
h.p. at 650 knots. The tremendous propulsive
power at high velocities is one of the principal
features of the turbojet engine.
@@gort8203 Are you familiar with the NASA engine sim?
My Uncle was a Test-pilot for Grumman in the 1960s and 70s. He helped develop the F14 while testing out of the Grumman Calverton Plant……
As a professional corporate/charter pilot and certifiable crazy person when it comes to airplanes , the Tomcat has always been my favorite when it comes to military aircraft (the F-16 holds a special place from living near Hill AFB all my life as well). That being said, I would love all of the information you would like to share regarding this spectacular aircraft. I will read, watch and study just about anything I can get my hands or eyes on when it comes to flight and aircraft, so as always, thanks for sharing your knowledge. No matter how much we know or might think we know, there is always more to learn on these subjects. Which in turn, makes us better aviators as a whole.
Thank you so much Greg. Your devotion to aviation history and knowledge is incredible. I have always love the history of flight especially WW2 era warplanes. And with your knowledge and easy to understand videos I can truly appreciate the engineering and piloting skill needed to operate these planes. Thank you so much and keep up the Fantastic work.
IIRC, the typical speed at which a jet engine reaches ram air recovery effect is 160 knots. Beyond that speed, ram air is providing increased thrust due to reduced compressor loads and increased internal air pressure supplied to the hot section and power turbine(s).
I’m going to have to download a copy of the Aerodynamics handbook to refresh my memory on the subject.
Thanks for the video, Greg. Always interested in F-14 videos. Ward Carroll does some very good ones.
I was wondering about that, I don't believe that was covered in the video. I may have missed it, that was a lot of information.
My father was a Naval Aviator, a test pilot at Pax River. He took me to an engine test on a F-14A. It was held by two stout anchor chains attached to the main gear. Chains large enough that I had a hard time moving two links. Serous stuff. The ground crew bundled me up in safety gear and then lit the fire. It was the loudest noise I have ever felt. The chief took me aside and asked "Do you know why we didn't take it to Zone 5 (Max A/B)? Because the anchor chains would snap".
That was completely inconceivable to me at the time.
Very cool story! Though I wonder if the weak point would be on the airframe, not on the chain.
“The loudest noise I have ever felt”
Good description, jet exhaust is sensed by more than just the ears.
@@TurboHappyCar F-14A's launch with full afterburner, both engines, and they stay til they're released, no chains. The chain would not break, the airframe would not break. No guarantee on padeyes in concrete though. It's probably a bad idea because if one engine just shut down, the sudden lack of thrust or tq from one side on the frame could move the aircraft left or right. Maybe. Realistically it's an unnecessary risk and wasteful to spin both up like that. I'd bet there's similar rules for F-15 turns, as well... unless it's only on the Tomcat because of wider engine spacing. F-15 had less problems with flat spins due to engine failure because the engines were closer together.
I seriously doubt the anchor chains were less strong/durable than the launch holdback bar that held the aircraft back on the catapult on the carrier.
Greg, you continue to put the most educational content out there. Top notch stuff. You should put together a course.
Greg. I absolutely love your content. Your explanations are so clear and easily understood that it really makes me feel as I have a handle on this subject material. I've been flying planes sporadically since 1998 (still working on my instrument rating) and these videos are just perfect for me. Thank you for doing what you do and and please keep it coming. Jz.
As a retired engineer IMO you are very good at technical explanation. If you ever retire, you should consider teaching the youngsters in technical fields. In my experience very few techies can effectively teach. Your use of piston engine analogies is very effective.
Thanks Bill.
Well done, again, as usual. Even more remarkable, making this kind of content (sort of) understandable to a non-pilot, non-engineer who's mathematically handicapped. For what it's worth, I agree that the F-14 is an interesting aircraft for a variety of reasons. I'm also interested, for obvious reasons, in early jets of the sort that my Dad flew in the late '40s and very early '50s - FH-1 Phantom, F2H Banshee, XF-88 (became the F-101), and the XF-85. Just as in the early 20th century, early jets saw a lot of "make it up as we go along."
I’ve only just started watching and I’m already excited to see the rest! I’ve never really understood the horsepower/thrust thing and 40 seconds in Greg is talking about it! Thanks, Greg.
I always hear that the F-4 Phantom flew like a rocket powered brick. Could you go over her performance and aerodynamics and tell us how extreme it really was?
My Dad flew F-4’s in Nam and Eval after.. After retiring from USN he worked on the Tomcat
29,500 ft. time to climb in 60 seconds.
Set altitude record at 98,557 ft.
Air Force flew to mach 2 on its first flight.
Aerodynamics were surprisingly good owing to its area rule fuselage
Maneuverability ok due to things like its vari ramp intakes , leading edge slats etc.
I would love to see a Greg video(s) on the Phantom. 👍
Good luck finding a brick with a glide ratio of 7. That's not worse than most fighters.
Maybe this evaluation of aircraft handling is relative to smaller, lighter, slower and / or earlier types.
I like how you showed several alternate ways to determine power. I calculated based on the mass flow I searched up for the TF30 and came up with a very similar 77173.4 kW, or 103491 horsepower.
Best aeronautical engineering channel on youtube
Thanks for the great video!
I remember quite well when I found out the difference between "thrust" and "horsepower" when flying the 262 in a sim after prolonged periods of 109 and P-51 "driving". I was astonished at what relatively flat an angle one could even outclimb piston powered adversaries, if one was patient enough and let the jet accelerate instead of aggressively pitching for climb like in the prop fighters.
Back to the main subject of your video: one could, of course, also argue that the jet is producing horsepower, if one measured the speed difference of the total mass of air going through the engine. After all, it is only the reaction to this process that produces thrust in the first place. 😀
As you already explained, the propulsive horsepower remains zero at standstill. Much like the drivetrain in a drag car not producing propulsive horsepower with the automatic transmission in gear brake and the engine on the two-step (the engine, however, WILL be producing hp).
Thanks DZ.
Depends on how fast she is going.
Totally looking forward to this video.
That is correct, speed is a key factor here.
Thank you Greg. Would love to see a video about the F-14’s glove vanes. Don’t think I’ve ever seen one.
Discussing changing center of gravity and center of lift with wing-sweep on the F-14 and other jets would be awesome too.
Keep up the great work! 👏👏👏👍
Not an engineer here, but i have been running some flight model experiments back in the day, regarding the F-14A and D for an old flight simulator i will not name here, as a part of a modding community for that simulator. When retaining the aerodynamic properties from the wing tunnel tests, having the thrust set to 17-18000pds per engine gave performance that matched the performance manuals much closer then the 20000+ pounds per engine. Of course, a lot of this may have to do with simulation-engine specific factors, but if we take into account that the same engine was used with the other lookup tables, then i think it's pretty safe to assume the installed engine was inside the 17-18 kpds category.
Dear Greg, Thanks so much for the effort and thought you put into these videos. I hope you and your family have a happy and healthy holiday season and a prosperous new year.
It would be interesting to hear about the horsepower that VTOL planes produce, while taking off vertically. Hope to see videos about the Hawker Harrier and especially Yak-38 and Yak-141 one day.
I second this, as well as the opposite (how do you figure how much thrust a prop plane has when stopped?). Something I've always wondered and could be interesting to discuss.
Propeller aircraft is measured in SHP via the twist in the torquemeter shaft.
How much force it takes to twist a shaft. Thats the way is measured on the c130j, i guess it is the same with the osprey and other propeller aircraft.
@@fsendventd You could chain it down with a big spring scale in the chains (these days you would use a load cell) and crank it up to see the maximum reading you could get on the scale. This would actually be useful information to know for, say, a carrier launch.
Thank you, Greg, I learned a lot today. Not only their benefits, shortcomings,, advasntages, disadvantages in full detail, Finally someone explained the differences between them and why turboprops are used on some aircraft types almost exclusively, until now, I have never been able to understand them.. :D
Witnessed an F14 take off twice in my life, Wings over Houston in the 90s and Texas Air National Guard I think. Those unrestricted day.
It was the LOUDEST plane I ever saw , flew off, climbed and did 90 degrees ... ! The year after there was an issue and it returned to field.
An Awesome plane !
For me the loudest was a hovering Harrier with full water injection
@@gavindavies793 I think the F-22 finally beat the Harrier, according to my "ahhhh" scale at the Miramar Air Show. 😂
@@TurboHappyCar well, we could try to beat all by getting my work's museum collection to fire up one of their Walter rockets from the Me163 Komet , but I don't think they'd have enough stof lying around lol
@@gavindavies793 INDEED it blasted up the Turf, thanks for reminding me @ wings over houston
@@gavindavies793 indeed Awesome also. Wings over Houston in OCT was fantastic Pre days of Mr Obamas cuts!
Would love to see a series on the f14! The f4 phantom would be pretty interesting too
I could watch your videos literally all day.
Wow I was just reading through this chapter at work and in my spare time (scientist by day with a CPL) on my Kindle. I have found that it's very enlightening even after doing my CPL well worth the read if you can get through how dry it is.
Personally I would love more Turbine and jet engine content really liked your video on the pull start Jumo engine.
MORE JET AGE stuff would be perfect. I am saving this video so i can watch it again to get a even better grasp on the concept of thrust and horsepower.
Now I'm curious to see a conversation with Greg and Ward Caroll ...
Thanks for the wonderful content, Greg! I cannot express just how satisfying it is listening to you explaining these concepts in meticulous detail but magically lightly. And every time I might feel left hanging for some detail, you feed me that nugget just before I lose hope.
I really appreciate also how you do your utmost to stay credible at all times and this is not necessarily the only way to make videos, but it is a good way and I like how you do it.
Please keep it up! and I for one would love that F-14 video as well as other jet-era aircraft.
I am glad you are interested in the 14! Can't wait for more!
The history and design of its flight computer is interesting, by martin marietta if not mistaken. It was a custom processor, to drive the wings angle automaticaly.
Unique or rare, most planes with variable geometry where limited to set angles.
Think the c.a.d.c was made by garret airesearch, en.wikipedia.org/wiki/Central_Air_Data_Computer
@@exup18 70s and instruction pipeline? Ahead of it's time I would say.
Once I sat in a cube next to a guy who wrote some of the F-14 code. He had worked on other planes too. He said that the F-14 was the most carefully engineered of them all.
Hey Greg, it is happening! I just read an article about peoples insurance increasing in price, and the people couldn't figure out why. Turns out the car manufacturers are selling your data to insurance companies so that they can see how you're driving!!! INCREDIBLE!!! I will not buy a new car for this reason! I think this is absolutely wrong!!! The whole purpose of buying a car like a Mustang is to have fun!! I have had several Mustangs in my life they were all 5.0s. They were very fast, and I had a lot of fun driving them on the highway on my to work ! I took full advantage of their great performance, and when I got into the city, I could really go nuts, fishtailing, and slamming gears because there are hardly any cops around. The manual trans on my 89 GT was Bullet proof! The rear even had an extra set of shock absorbers mounted horizontally to keep the wheels from slamming into the wheel wells! What I'm saying is why would I buy a new Mustang when Ford or whoever is going to tell on me and cause my insurance to go up?? I have a good driving record, and I always would make sure it was safe when I messed around. I wouldn't put other people in danger or smash up my car. The car manufacturers are going to lose business when people find out about this. Especially mucsal cars or sports cars! Somebody will figure out a way to disable this feature. They always do. Car manufacturers have no right to be spying on you like that!! I see lots of lawsuits when people figure this out coming on the horizon or people insisting on a law against this if there isn't one already. I think I would rather put the money into restoring my 1998 Lexus LS 400. Yes, I have mellowed out in my old age. The car is 26 years old and it's my daily driver! Lexus went all out building this car because it is the first model they sold when the company started. They wanted to beat Mercedes and BMW, so they used top notch materials and design. The V8 engine is an incredible design. I believe it's even used in airplanes. It gives that big car a zero to sixty in 6 seconds. Not bad for back in the day!
I love your tangents.. I already understand all the physics but I still love listening to this content.. All the little details, stories from the real world...
Would love to hear about the F-14A's high speed performance vs the B model. Heard someone did Mach 2.6-2.7 and had to reduce the throttle because the glass was getting too hot, or something similar.
I've heard the same. Would love to see some research into this by Greg The Mighty.
That’s just rumours. The fastest the F-14 ever went was 2.34 Mach in early testing.
As for the B model the F110s actually work in a different way to the TF30. To generate more thrust the GE pushes more air. The PW gets hotter. Thus at high altitude the TF30 actually produced more thrust but was less efficient. With the thin air the F110 doesn’t have as much air to push.
The F-14D can’t actually make 2.0 because it doesn’t have the extendable glove vanes at all. Without them no F-14 can get past 2.0 Mach. The glove vanes bring the centre of pressure of the jet back within limits at high speed. Otherwise it creeps back and creates a nose down pitching moment. This increases the speed and pushes the centre of pressure further back and the jet enters an unrecoverable dive. All A and B models had the glove vanes welded shut.
Sorry to be a party pooper but no Tomcat ever got past 2.34 Mach.
@@dat581 That is exactly why I'd like Greg to dive into it in more detail, pull research documentation and see what the test pilots had to say. It would be interesting to see if the Tomcat with TF-30's could actually overspeed like that. What would be really interesting (I'm just dreaming) is to see a Tomcat with technology the SR-71's engines used to make it mach 3+. Who knows how it works handle high AoA, though. Would love to see a huge thrust F-14 with a big AESA radar, stealth considerations, potential mach 3+, yadda yadda. One can dream....
@@speedycpu The F-14 is never going to stay above 2.3 for long without melting. The TF-30s have been proven to 2.5 in the F-111 and they are essentially the same engine with different nozzles.
The F-111, which is a slicker airframe than the F-14, would only get to 2.5 when clean and with the engines in very good condition. A timer starts above 2.0 and the jet has a limited time before it melts. The F-14 is made from similar materials.
As for the SR-71 engines that would be pointless for several reasons. The primary reason is the F-14 rarely got above 1.4 in service. It was actually limited to 2.0 by the Navy. The ramjet is also not suitable for a fighter at all. Most people would be surprised how much of a dog the SR-71 was until it got up to cruising speed. Most fighters could easily out accelerate it.
People love to quote the top speeds of jets but they are actually one of the more irrelevant statistics in service. The F-35 is limited to 1.6 Mach because that’s what the USAF wanted. The jet has the aerodynamics and thrust to easily make 2.0 but it would need new intakes.
The reality of fighters is quite a bit different to how they are portrayed as you can tell from Greg’s videos!
@@dat581 I read the SR climbed out at 400+ so thats impressive . Thats not the first time I've heard of F14 glove vanes shifting lift .
A poster on a vlog who sounded legit'ish (said he was a military pilot or something) stated the F35 WITH STORES under the wings will out accelerate a clean F16 when ask about F35 performance . Now it there is any truth to that Fat Amy is maybe not so fat . I know it has the most powerful engine but a clean viper is a rocket .
At an airshow quite a long time ago saw an F-14 performing together with an aerobatic prop driven bi-plane. They did a number of loops with both tangent and coincident at the bottom of each loop. The F-14's loop was bigger, guessing from memory between 5 and 10 times as big. Impressive management of both airplanes.
Some videos pop up in your feed and you think oh good I’ll save that gem till I have my full attention, your videos always do that Greg.
The F-14 and F-15 are high on my list to learn more about! Loved this video like i love the ones about the WW2-era.
Another masterpiece - we wish you a safe and happy Christmas from England everyone.
Looking forward to your future sponsorship deal with Manscaped where you discuss the finer points of aerodynamics and drag!
lol, that won't be happening!
my favourite jet! followed by the ee lightning
@@guyk2260 Astounding aircraft.
Magnificent!
Nice video! One thing I would like to comment on. That 325 number is important as in terms of Knots, this equates to 370 mph ( APPROX ) which as it turns out is the begining of the middle flight regiem ( subsonic, transsonic, supersonic ). For those who do not know this is the velocity where the air cannot get out of the way of the object moving thru it and starts to compress. It is my understanding that this is why prop drive A/C have a hard time getting above 400 mph. The prop, wing and fusalage all compressing air starts to use up HP very quickly. As a former, now retired, industrial air compressor tech, I can tell you compressing air requires lots of grunt ( HP ) and generats lots of heat. Using flooded screw type of compressors some industries, my case sawmills, can heat large parts of the mill using a well designed heat exchange system. A 200 hp compressor can generate 80 to 100 BTUs. Looking at an axial compressor, turbojet or turboprop, with a multiple turbine set up one stage or more will be used just to run the compressor(s)/fans. The difference between an electric and internal combustion engine driven compressor efficency is around 2 to 2.5 : 1 in the electrics favour. So using your formula, a Boeing Dreanliner using the latest 110K lb thrust engines will generate a theoretical value of 350 to 400K hp. Nice considering a Gerald Ford class aircraft carrier generates about the same. That 370 mph thing, I did a quick check of hp vs speed on a couple of WW ll a/c Spitfire snd Mustang, A thru ??? models and this idea holds up. I have not done this with any other a/c, P38, P47, F4U etc.
I think also the reason why jet can accelerate a flying object past this compresssibilty barrier is that the trust it creates is made of very high velocity air mass compared to propeller. The impact of say 300 kts of airstream created by forward speed compared to the exhaust air speed of the jet engine is far less than the same speed with a propeller aircraft. BTW propeller is kind of the same as a jet if you think about creating trust by way of accelerating an air mass (be it behind a propeller or a trust tube) Also this is why modern airliners cannot fly as fast as early jet airliners, because modern airliners jet engines became more and more like propeller engines (fan up-front) and less jet engines (simple core jet) and their exhaust velocity is thus far less. They are optimized for the speed they operate at.
I would be very glad for more about the F 14. Thank you.
Thanks Greg! It's kind of interesting that while I was doing some work at Mt. Storm Power Station in West Virginia, I got to see some Tomcats flying through the nearby valley at speed. I was not more than a few hundred feet away, and 50 to 100 feet above them, so I could see right into the cockpit - it was pretty cool.
Great video. The F-14 is my favorite aircraft of all time and I would really like to see more videos about it and other more modern fighters.
Great video. Started watching a few days ago while watching dishes but paused until I could really pay attention. I will definitely share with my colleagues who are interested in not just planes but engineering in general. I didn't used to be a big fan of the F-14. Probably because during my time at the AF academy all my classmates who wanted to be pilots would quote Top Gun non stop :(. Looking back it does appear to be an interesting plane and I would love to see more Tomcat stuff!
Thank you for not shilling on the channel. It's increadibly annoying.
I greatly appreciate this video, Greg. I was just looking into thrust/hp-kw conversion and Google was useless.
I can’t wait to see you cover the Tempest. It’s an aircraft I should have known about decades ago, but only learned of its existence recently.
Those WWII panels would make one hell of a cool sim setup!
I thought that you also were going to compare fuel flow which could also be shown in horsepower, so I did the calculations myself.
Sticking to the F1 grid analogy - a single F14A with afterburner consumes about 922 000 horsepower in fuel,
a modern F1 engine is limited to about 1676 horsepower in fuel due to maximum fuel flow restrictions,
so if my calculations are correct and estimations are not that far off then it means that
a single F14A consumes as much as 27.5 full F1 grids worth of "fuel horsepower".
P.S.
Keep up the good job, I really love your videos!
Greg, you need to contact Ward Carroll. He has a channel on RUclips and was an F-14 pilot when he was in the US Navy. His channel is interesting. I watch it, as I watch yours and Military Aviation History on a regular basis. If anyone can give correct info on the Tomcat, it's Ward.
He was a RIO, not a pilot, but that doesn‘t in any way detract from his superb channel. It’s a must for anyone interested in the F-14 or naval aviation.
All this stuff is way above my head but as usual, you explained it in a way everyone can understand the concepts and principles. Plus, you picked a great aircraft to help illustrate it.👍
This is my favourite RUclips channel. It makes me play my il2 in VR
Edit dammit now I have to learn how to fire up a jet in DCS
Very well done Greg. I hope this turns into an extended effort for you and of course my previous offer still stands.
really looking forward to this Greg! anytime, baby!
I hope you like it. It's quite mathy. I even had to do a tiny bit of trigonometry.
@@GregsAirplanesandAutomobiles haha I can always guarantee when you make a disclaimer regarding the technicality of a video, it's going to be a good one!
BTW Have a blessed and Merry Christmas and a Happy New Year. Thank you.
Thanks Brain, and Merry Christmas to you and yours.
Your channel enriches my life.
That's nice to hear. Thanks.
I like the "pushing the car with the handbrake on" analogy. I was thinking of the difference between a motorcycle using it's engine to spin the wheels versus someone with a big wrench applying a torque to the wheel.
Yes, the person with the wrench may be able to apply just as much torque as the engine, but will not be able to apply that much torque AND spin the wheel at high RPM.
I think some confusion comes from the way we say the engine "has" horsepower as if it's an intrinsic property, when really horsepower is a result. An IC engine appears to have intrinsic horsepower because the way horsepower is defined for an IC engine is linked directly to the mechanical function, so it can't avoid producing horsepower while in operation. The way power is defined in a jet is decoupled from the operation of the engine.
@Kirk Wolfe what I mean is that the power of a piston engine is directly related to the torque and rpm of the engine itself, but the power of a jet is related to the thrust of the engine but the speed of the whole vehicle, not the rpm of the turbine.
There is velocity of the mass-flow of the jet exhaust which can be used to determine power, even when stationary.
@@andrewdynes5300 I am not arguing that there is no way to measure power from the jet engine itself. I am saying that it is confusing to people because of the way power is defined and measured in IC vs jets. Piston engines appear to have intrinsic power because of the way bhp is defined and measured, so people assume jets do as well. But as we see in the video, it's all about how you define power.
Greg, you are so real. Just doing it as right as you can. Love it.
Please more F-14 stuff. Systems, avionics in detail, flight optimization, please
Get too close for missiles and switch to guns.
Thanks Greg! Your channel, along with AgentJayZ and Blancoliro fulfill my aviation geek needs!
Many hours of AgentJayZ prepared me to understand this video.
AgentJayZ's channel is quite good.
If you have any interest in machining and the like you might also take a look at 'Rotary SMP'. He is an aircraft mechanic by trade, and always manages to spend a couple of minutes on some aside that is aircraft engine related in his videos. The most recent one spent a couple minutes showing the attachment methods for an airliner jet engine.
Congrats on 90k Greg!
Thanks Enigma. I feel quite lucky.
so HAPPY to see you are playing DCS
I am too, I'm playing it a fair amount these days.
Great video, Greg. This video should have been titled "How Horsepower works, using F-14 as an example"
I learned more basics of thrust/horsepower/torque/etc than I did about the F-14, thanks!
Also, your bit on turboprops was spot on. I believe the Saab uses it's port engine as an APU by inserting a locking lug into the gearbox, so the turbine will generate power for the accessory gearbox, but the prop won't turn. I've got plenty of time in the C208 and it was great holding 170knots to short final. Very quick aircraft for short flights.
Hi Raptor. In the second paragraph of the description, I make it clear that this video is intended to convey certain concepts using the F-14 as an example and not really an F-14 video. Of course I also answer the question posed in the thumbnail inside of the 30 second mark, so I think I'm good there. Great point about the Saab. The Cessna 208 is indeed great at holding that speed until the last moment, it's a wonderful airplane.
The nuclear powered scramjet built for project pluto cruise missile (more like a flying locomotive) was tested at full power for 20 minutes and put out power equivalent to 250,000hp and would have flown at Mach 3.5 at tree top height.........its shock wave killing people on the ground let alone the nuclear fall out in the exhaust. The engine could travel from the USA to the USSR and still have plenty of fissile fuel to circle the USSR polluting it without fallout in addition to its magazine of multi megaton H-bombs. Stanley Hooker in his book regarding jet engines, placed emphasis on the improvement of compression ratios inside jet engines to denote their improved efficiency..........compression is key to getting the fuel to provide more effort per unit of fuel. Always interesting videos, thanks again Greg.
Greg,
The graphic with the horse at the beginning of this video summarizes the classical relationship between force, work, and power.
A force measured in ‘pounds force’ can also be termed thrust in the aircraft world.
Work is force applied to an object to move it. Work = force x distance; measured in foot-pounds
Power is the measurement of work per unit of time. Power is the rate that the work is done.
A force applied to an object that does not move does no work. Work requires movement. Without work, power is zero.
I'm glad you noticed that, I put it in there for a reason.
Great video as always!
I’d love to hear an analysis of performance between the F-86 and the MiG-15.
F-86 > Mig 15
Because; All-flying stabilizer.
The Russians obviously read NACAs research reports from the early 1940s on streamlined bodies with internal flow. Because they ended up making a nearly identical aircraft to the Saber, while they obviously missed several key advances that were unpublished and kept top secret between the reports they had access to and the launch of the F-86.
@@Triple_J.1 Even with the flying tail, the MiG still had an edge in maneuverability. It also had a higher ceiling and climb rate allowing it to pick its fights. The two aircraft were almost a match speed wise, though the F86 was slightly faster. The F-86 had a much weaker gun package (the USAF was still fixated on the.50 cal). However though the 23mm/37mm cannon mix on the MiG gave dispersion issues, any hit on a Sabre was bad news (some 20mm cannon armed Sabres were tested in Korea with very good results). What really gave the Sabre an edge, was the radar assisted gun sight (which the Soviets quickly copied from downed Sabres).
Excellent topic Greg. I am a fellow airline pilot, E190 and CRJ type rated Capt, never been in the military aviation but it has been a life long passion and especially naval aviation regardless of the nationality. There is a characteristic of the F-14 that would be interesting if you dig into and that is the rocking motion on the longitudinal axis at high AoA esp at high G. Many planes show this tendency but it seems more pronounced on the F-14. Thanks and keep theses awasome vids comming!💪🏻
That would be an interesting video. However if I make another video featuring the Tomcat I'm going to start with something related to the propulsion or electrical systems.
@@GregsAirplanesandAutomobiles good idea, i read somewhere that some of the first microprocessors in the world were used in the Tomcat.
I know that you focus mostly on fighters, but I'd personally be interested is seeing a little expansion on this subject. You mentioned the turboprops, and turbojets in terms of there efficiencies, and advantages at their respective operational speeds. Might be interesting to throw turbo fans into that mix as well. In truth; some of the most powerful jets out there are turbofans, and they have a relitivly wide operational speed range falling in between the turboprop, and turbojet. If a fighter must be used as a starting point; Saab Viggen did use a turbofan. ; )
Hi Central, good points. The Viggen uses a Volvo turbofan which is basically a Pratt and Whitney JT8D with the addition of an afterburner. I have a lot of time flying the JT8Ds in 727s. It's a very low bypass turbofan, at least low bypass by modern standards. I probably should cover turbofans as they are the standard type of jet these days for anything subsonic. Even the newer fighters have turbofans, although low bypass and with afterburner.
@@GregsAirplanesandAutomobiles I have a theory that the whole conspiracy concerning vapor streaks in the sky springs from the operation and increased efficiency of these engines.
SMH
@@sadwingsraging3044 Contrails (condensation trails), as we used to know them, will occur with piston engine propeller aircraft. They aren't a direct function of jet engines as many people seem to believe. They were a big problem for the 8th Air Force when doing bomb runs over Germany in B17s in the 1940s, because the whole formation would have contrails pointing to the planes, giving the Flak gunners a hint of where to aim.
@@lwilton I was intentionally being vague with my wording.
Didn't want to awaken the algorithm beast. You never know what the flighty thing will be displeased about and take it out on Greg's channel.
Unless I am wrong these new ultra modern engines are in effect nothing more than high efficiency highly highly HIGHLY modified shrouded props with maybe a little fuel tossed in somewhere for expansion and keep the whole thing spinning at the same time.
Just an observation I have thought about occasionally.
You touched on the topic when comparing turboprops and generic jets.
Turboprop thrust is maximized to move a large mass of air. A turbojet (particularly afterburning jets) maximize pressure of air (low pressure in, high pressure out). Fanjets and the new Geared fanjets are trying to be turboprops (maximum airflow), with a very slight increase in pressure.
Thank you for another great video Greg. It's not something I've been thinking about, but I did wonder were the conversion number came from during AME school.
Hi Greg, Confused thinking, and vaguely remembered high school physics lessons led me to ask the question. I went back and thought about it again. The exhaust gasses have mass and velocity, that is momentum, which cannot be tied to horsepower. I suppose that if the velocity of the mass of air entering the combustion chamber could be measured against its velocity on exiting the turbine, then the work done in accelerating that mass air could be calculated and hence horsepower. But, that is another rabbit hole! All the best!
Thanks Finlay.
When i was young it took me awhile to understand the difference between torque and hp and in retrospect, most explanations were just bad. You're explanation of this similar concept was well done. I think boiled down to its simplest form, the difference is that Torque and thrust are measures of force while hp is a measure of work.
The statement that "it moves air, therefore it has horsepower" is actually true.
To generate the high speed flow out of the engine, the exhaust gas flow undergoes a change in specific enthalpy in the nozzle and this change multiplied with the mass flow of air equals a power figure. Expressed as a different but equally true concept, you have to apply a force to accelerate the exhaust flow and that flow has velocity, therefore there is power being generated in the engine. The ratio of this internal power compared to the propulsive power is the propulsive efficiency of the engine, analogous to the propeller efficiency line in the charts turboprop charts you showed.
The only important power number for performance calculations is the propulsive power though.
I'm not sure if you watched the entire video before commenting, but what you said is more or less what I was saying in the video. Sure it makes horsepower when stationary, but not propulsive horsepower. Engines are rated in horsepower which can be used for work, not just the power needed to spin itself. In other words, when we say "horsepower" we are normally talking about propulsive horsepower.
@@GregsAirplanesandAutomobiles I was thinking that. 'Work = force x distance". If it's not moving, no work is being done.
Greg, if you aren't already aware of him, check out Ward Carroll's channel. He was a Tomcat RIO and I believe later a pilot. He has done a number of videos on many aspects of the Tomcat and rundowns of actual missions. His videos are often very detailed like yours. I'm sure he could either answer many questions or point you in the right direction, not that you seem to have much trouble with research, and could no doubt offer many real world "When you do that, this is what happens" type of stories.
Very nice video. Lots of great technical info to better understand thrust vs hp.
I love your compendious videos! Surely the (empirically determined) maximum rate of climb is the ultimate measure of the power of an aircraft. I remember that my 5th grade (or was it sixth? ca. 1968-69) teacher got us to recognize the difference between force and power by getting some of the (most self-important) students to take up opposing positions on his desk and push for all they were worth. Of course the desk did not move and he declared that despite all the force exerted, the amount of work achieved was zero. As to the Tomcat, using an empty weight of 20 tonnes, and published rate of climb of 230 m/s, yields a horsepower of about 60,000. Ludicrous!
I always remind myself that one of the kinds of turboprops are just tiny turbojets with a propeller bolted to the front and that the other kind is sort of a gas turbine driving a propeller with it's exhaust gases.
It's probably not completely true, but it does give me a great picture in my head and it seems to stick in my brain.
F-14 is a very interesting airplane. And it has variable wing angle control. So, there is lots of stuff to tell about.
If I recall correctly some of the wheel-driven land speed record cars turned surplus military jet engines into something akin to the free shaft turbo-prop you showed, by directing the unmodified jet's exhaust into a separate turbine to drive the wheels.
Thanks for the deep dive Greg. Always a treat. Can you in the future look at why I have always read the A was under powered compared to it's contemporaries and the latter B/D models?
Greg, when you were talking about BSFC (brake specific fuel consumption), it actually should have been BTE brake thermal efficiency). For BSFC a smaller number is better as in less lbs of fuel to produce a given amount of power. BTE is the ratio of output power divided by the fuels energy for a given quantity of time.
I probably burned through that too fast and should have spent more time on it. I was trying to shorten that part of the video to get back on track.
Not sure if it was covered in the comments already but the issue with power and thrust has always been a problem for engineers that missed that day in physics class. Energy, Work, Power, Force.... energy is the capacity to do work, work is force times distance (also torque times RPM in angular systems), force also has a distance element (mass x distance), and propulsive force has the thrust and velocity elements. So I can use all my energy to the peak of my power and push against a brick wall, but unless I move the wall, there is zero work and zero force. Along the same premise using a small scale experiment, I can spin a 24x12 propeller to 7100 RPM and develop 47 pounds of thrust with 8 HP at the shaft (ESHP). Using the same 8 HP, I can also spin a 29x12 to 5490 RPM and develop 54 pounds of thrust. Of course, the 12 pitch to 7100 RPM may result in a higher pitch speed, but the 7 more pounds of thrust from the 29x12 will result in better and instance accelerate.
More Tomcat for sure.
Merry Xmas!
Great episode! I would love to see more content on the F-14. Also the F-16, P-51 & the F4U Corsair ( my top 2 post WW2 @ top 2 WW2 fighters)
Interestingly, Agent Jay Z channel argues the power statement on a rested plane, citing the mass flow displacement.
If you look it from another perspective, if you put a plate behind a non moving tomcat at full afterburner and the plane can be moved forcing resisting hydraulic pistons for example, you might find that work has been done. However since you don’t see anything if there is no visible solid barrier, displacement of air molecules is not considered work.
It is worth thinking about it IMHO.
I have thought about it. I'm not sure what Agent J is saying (I don't know him), but AFNA is clear on this point and the physics of aircraft climb performance back it up 100 percent. If he is saying that with zero forward motion a jet engine is producing propulsive horsepower, then he is simply wrong.
@@GregsAirplanesandAutomobiles It is theoretical. Horsepower is measured where there is movement, for example the flywheel. Sure, but there is movement at the turbine wheel at the jet plane as well. If there were a device to measure it, there would've been some horsepower.
However, AFNA uses theoretical conclusions to explain /and help with calculate/ some of the events in flight.
It is pretty much like MAC. MAC is mostly theoretical, since there is no rectangular wing with such shape with which you get your measurements for WnB settings, however you use MAC when you set up your Beoing jet.
Again, MAC is theoretical and only theoretical.
I am not insisting on this, but it seems more logical than in the AFNA - > if there is a mass flow movement, then work has been done, then HP can be theoretically measured. Jet engines used to produce power on other applications than jets have that measurement. Semantics.
Maybe its worth taking a look: ruclips.net/video/40OV47wee7o/видео.html
Damn. As much as I appreciate the F-14, after Greg's last video, I was hoping for a continuation of the P-40 Warhawk (similar to his series on the P-47 or FW-190). Still, thank you, Greg. Love all your videos.
This is awesome! Loved the turboprop tangent too. I had the same thought.
Thanks Greg, I always why they talked about HP with a jet.
Have a Merry Christmas!
F14 is one of the best looking jets 👍and your lessions about aviation-technic are the best on youtube!👍
Thanks and Merry Christmas.
Great video Greg I do love your piston videos but would also really enjoy more jet videos.
Thanks for the vid and the cockpit rockers lead, gonna check them out. Thanks again.
Hey Greg, you have a really intuitive understanding of propulsion systems, could you in the future make a video comparing and contrasting piston, turbo fan, turbo prop, and turbo jet engines? Or even a video comparing the benefits and drawbacks of the different piston configurations such as inline, opposed, v, and radial? Forgive me if you have previous videos on the subjects, I just discovered your channel today!
Thanks for visiting my channel. I'll do exactly that. I have never talked about turbo fans in detail and a lot of people are asking for that. I do have some videos about jets, and of course a lot about piston engines.
I remember that when I was a wee lad (9?) my dad went off ranting if I happened to ask about the horsepower of a Viggen or such (he was an engine engineer for SAAB).
You always have something interesting and full of information to say.
The F-14A is my all time favorite Cold War-era jet. On paper, it's rather lackluster (compressor stall complaints aside) but in actual practice, it's quite a maneuverable aircraft despite its power deficiency once again on paper.
What I would like to see someday is some information on how the Tomcat did in combat during the Iran-Iraq War since that's where it enjoyed the majority of its success.
Agreed-the main issue with the TF30 powered F-14A was not necessarily its thrust to weight ratio but rather the engines poor stall margin.
Most pilots that flew the F-14A felt that given its fuselage and wing design that the TF30 provided adequate thrust. The reliability of the TF30 in air combat maneuvering though was another matter.
Despite the increase in thrust that the F-110 engines offered in the F-14B & D variants. The F-14A with the TF30’s could still out perform them in certain high speed regimes of the flight envelope.
There was a phenomenon called a “ram effect” that benefited the TF30 in that scenario. I would love to hear an informed explanation regarding this.
Another great video! Even when you go off on a tangent it is great info.