DDD3: Boeing 727 - Part 1: Cool Engineering Ideas on this Trijet Pioneer
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- Опубликовано: 2 май 2024
- In Part 1 of this third Design Deep Dive we review some of the engineering highlights of the Boeing 727-100/200, from its interesting landing gear, through its ‘belts and braces’ yaw damper, to its impressive high lift system. The tour features some beautiful surviving examples of this now very rare bird - M-FTOH, G-OSRA, G-OSRB.
Selected references
[1] “Case Study in Aircraft Design - the Boeing 727”, American Institute of Aeronautics and Astronautics Professional Study Series, September 14, 1978.
[2] “Boeing 727, A Carefully Optimized Short-Haul Jet”, Flight International, 9 May 1963.
[3] Phillips, W., “Mechanics of Flight”, John Wiley and Sons, 2010.
[4] Gwynne, B, Lyon, P. “Magnesium Alloys in Aerospace Applications, Past Concerns, Current Solutions”, Triennial International Aircraft Fire and Cabin Safety Research Conference, 2007.
[5] Rudolph, P. K. C., “High-Lift Systems on Commercial Subsonic Airliners”, NASA Contractor Report 4746.
[6] Giesler, R., “The D. P. Davies Interview on the Boeing 747, the Trident, VC10, One Eleven & Boeing 727”, Royal Aeronautical Society, 1992.
[7] Gebhardt, G. T., “Acoustical Design Features of the Boeing Model 727”, Journal of Aircraft, Vol. 2, No. 4, 1965.
[8] Stroud, J. F. and Davenport, C. R., “Propulsion System Design for Maintainability in the Lockheed 1011”, SAE Transactions, Vol. 78, Section 3: Papers 690361-690559 (1969), pp. 1433-1443.
[9] Wallick, R., “Growing Up Boeing: The Early Jet Age Through the Eyes of a Test Pilot's Daughter”, Maian Meadows Publishing, 2014.
[10] The D. P. Davies Interviews on the Boeing 747, the Trident, VC10, One Eleven & the Boeing 727, The Royal Aeronautical Society, 1992 (interviews conducted by Rodney Giesler).
[11] Mohler, S., “Wind-US Flow Calculations for the M2129 S-Duct Using Structured and Unstructured Grids”, NASA/CR-2003-212736. 
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Very interesting, thanks. I flew the 727 (late 1968 ex-United 727-22QC's with JT8D-7B's) for 5 years (about 2 years of that in the climb, I think!) world-wide in the Royal New Zealand Air Force (RNZAF), where we had a very free hand in use of the flight envelope - far exceeding that which would have experienced in airline service. Many points you mention ring many bells - we were very enthusiastic about our machines, learning much about the way they worked (partly as a result of doing the same conversion ground-school course as the professional flight engineers). Ours had no nose-brakes - unsure if they ever had been, but the evidence was there. The Dutch roll was an issue, with the restrictions you mention for operations even with 1 yaw damper inoperative. We did most of our sim training on the -200 (at UAL), though would use the -100 sim for Dutch roll training. The -200 was relatively benign in Dutch roll (stable, as I recall), though the -100 would continue to diverge. Expectation was that it would eventually rip the fin off if yaw was allowed to develop beyond about 11*. Recovery actions included extension of the speed brakes, which pretty-much solved the problem, so I reasoned that once the lateral stability of the wing sweep was taken out of the equation, the directional stability took over. Very interesting also with the diagram of airflow through the S-duct at the compressor face: the #2 engine would compressor stall if not handled properly (e.g. excessive use of reverse during reverse taxi, or not reconfiguring the engine bleeds prior to closing the throttle at high altitude). We had free use of 40* flap, though the landing technique was very different and most pilots found that the landing distance was shorter with a well-flown 30* landing. My answer was to suggest practising the 40 option more - it was only 4 knots less in the Vref, but by the time the squares of the speeds is applied, the effort to stop was much less and the effect on the airframe on rough runways must have been good - the lower speed and greater drag after touchdown just seemed kinder to the airframe. The full gravel kit (optional) included retractable lower anti-coll light - we did operate into a couple of South Pacific coral strips, where we just taped-up the light, brake lines and lower flap surfaces.. Stalling: never did a full stall, though completed a number of post-C-Check functional test flights, to a prescribed weight and balance and fuel load. One check was the stick shaker activation at 40* flap - the indicated airspeed was 96 kts (about 4 knots above the stall as I recall). It was benign at that and recovery was conventional - I was aware of the stick pusher requirement in the UK, but wasn't aware of the aft CG effects..Wow! We also checked the overspeed 'clackers' and regularly saw 0.92 (limit was 0.916 I think) and noted the symptoms of the upper buffet. Once seen, you'd be having a bad day to confuse that with low speed buffet or stick shakers..things may be different in times of stress though. I last flew the 727 in 2000, then moved to 22 years on the 777 (all production versions) - a great machine but 'antiseptic' by comparison. Now rated on all 737's, which aren't a patch on the 727.. ..Thanks again.
Wow - thank you so much for sharing your fascinating recollections! I was particularly interested in your thoughts on handling Dutch roll - 11 degrees of yaw is less than what I would have guessed as a threshold! Do you recall ever seeing (in the sim?) yaw and roll go out of phase in the Dutch roll? I sometimes wonder whether that is a factor in the unpleasantness of an aircraft’s handling from a pilots’ perspective…
@asobester Sorry, no! No recollections about the subtleties of the Dutch roll - we were heavily focussed on the handling technique of applying opposite aileron at exactly the right time on each reversal of roll - very easy to get it wrong and make things worse. I suspect the bigger issue could also have been simulator fidelity - knowing what I think I know now in this regard, due to some exposure to the latest UPRT training as an instructor, I'd be pleasantly surprised if the Dutch roll in the -100 sim at UAL was entirely representative. While I'm here, the tailskid could be touched on landing - a colleague did it with an over-rotated flare at high density altitude. We had the odd scrape on takeoff - one when the captain attitude indicator was a little in error - at flap 5 (usual at heavy weights) the pitch attitude was VERY close to the skid contact attitude. I scraped the skid with a slightly too-enthsiastic airshow flap 20 takeoff, slightly compressing the honeycomb cartridge, but not knocking the tell-tale off, so it was still OK to operate. As you probably know, the 777 has a tailskid on all -300's made until about 10 years ago, when the effectiveness of the TPS (tail strike protection system) was proven (Boeing legend had it that the TPS allowed confidence in higher pitch rates with a V1 cut but kept the tail 3/8" off the ground during the V1 cut testing, where the earlier -300's had a number of tail strikes). All the 777's have a tailstrike indicator (though a strike is still possible in the -200's after the main gear is airborne, also missing the tell-tale..). Rotation rate is important - some of my former operator's older -300's had a maintenance terminal where you could look at pitch rate and pitch values for the last takeoff, and the resultant tail clearance. I've seen 12 inches clearance after a near max-weight departure. Anyway...all in the 'sealed section' of my logbook!
Thanks for your fascinating input you have had a full interesting life . As a child I was always interested in planes the USAF had a base just along the road from me at Prestwick . They still are there mainly Galaxy’s come and go . I remember back in the 60s German f-104s Starfighters coming in as well . When I was over in Las Vegas, San Francisco, LA late 90s we done internal fights on MD - s oh I was scared the way the pilots threw them about I was told by an American fellow passenger that lots of pilots were ex military. Also I remember being on a stretched MD and I thought it wasn’t going to take off seemed so slow . I still have great love for planes as a child my parents took me over Europe and mainly on BAC 11-1 s . My fav plane to date still is Boing 707s loved them
@@kerrywilton8266 Fascinating stuff. Do you know if the clearance was calculated (from the pitch and height signals?) or was there some sort of clearence sensor under the tail that generated an inch precision value? Presumably these stats came in handy when they were designing the semi-levered bogie for the -300ER?
American Airlines put a stop on the flap selector locking out full flaps from being used, I was functional test on the 727
This video is devoid of any hype. That may not sound like such a big deal, but it is so exceedingly rare in current memory that I almost forgot what a video comprised solely of facts and information felt like. Well done
Thank you 😎
I mean the intro is pretty hype.
the best days of aviation... when being a pilot meant something and you got to really fly the coolest stuff
Presenter managed to make a highly technical video quite interesting.
Flying on Mexicana's 727-200 fleet was the best of times for many of us. Thank you so much for the splendid amount of detailed information you provide in this video..
Glad you enjoyed it! 😎
The Hawker-Siddeley Trident was the first tri-jet airliner and flew close to a year before the 727.
It had less speed, range and payload than the 727 but was a solid machine.
I flew the B727-200 in the mid nineties and loved it's speed and excellent handling.
Unfortunately it's large swept wing coupled with a narrow track landing gear made landings quite a challenge!
Yes, the Trident was the first to fly, but the 727 was, as far as I know, the first in airline service. Do you happen to have flown the Trident too? Interesting insight re the landing gear - I should look into gear track/span/sweep comparisons across similar sized aircraft for Part 2!
YES the trident was first but far from a solid preformer. equipted spey engines it was cronicly underpowered and need a long runway to get airborn. british gov ruined the plane with too many desighn changes.
You’re spot on! Handling was excellent right up to the flare when predictability went right out the window for even the most experienced pilots. We had a saying on the 727: one good landing, you were a good pilot; two good landings in a row and you were lucky; three good landings in a row meant you were a liar!
My flight instructor for the Piper Tomahawk qualified as a flight engineer for an airline flying the 727, and he had something to say with the sensations riding a 727 as an airline passenger, especially towards the back of this aircraft.
He hold me that it landed at a substantial fraction of take-off power, whereas it was possible to land one with one engine working, it was a "special procedure" that ran that one engine at full power.
I remember as an airline passenger that when the announcement was made "put your tray tables and seatback in their full, upright position", punctuated by the rumble of the gear coming down, there was a noticable increase in sound from the engines. I also had the sensation that the nose was pitched up, not just in the flair, but on short final.
I don't know of any current-generation jet flown this way, where landings appear to be made under much lower power settings and with slight downward pitch until the landing flare, more like propeller aircraft.
Was the 727 draggy in its landing configuration, making it a kind of STOL able to land on shorter runways? Or is the impression I am getting as a passenger the result of changes in how jet aircraft landings are flown in recent times?
Living in Chicago, I also had the impression that there were more than one bad accident resulting from hard landings in this type with crews transitioning from propeller aircraft. The Chicago Tribune gave an account of one such hard landing which set the plane on fire and the cabin full of smoke, where only two persons seated on the exit rows had the presence of mind to open the doors and escape. This newspaper story is the reason why I study the seat card, look where I am and count the rows to alternative exits and pay attention to the flight attendants' safety demonstration on each and every flight segment I fly as an airline passenger.
Is all of this connected to its novel-for-its-introduction high-lift system and steep flap settings and different-from-other-aircraft flight characteristics?
As to the remarks of @Hedge1011, as an airline passenger, I don't seem to remember "greased" landings in the 727.
The 727 was a delightful aeroplane to fly, and, contrary to popular opinion, was very easy to land. With 3000 lbs of fuel flow set on each engine and landing flap selected on the final approach to land, It became a very stable platform all the way down to the runway, needing only very small power changes. The landing itself was not unlike landing a Cherokee 140, it was so simple, but pilots would speak of 'pushing forward' just before touchdown, which really upset the poor old thing! Crosswinds didn't seem to have too much effect either on the aeroplane during landings, having two powerful rudders. Selecting the landing gear down and flaps on the approach, produces a lot of drag, hence you probably heard the engines spooling up a little to offset this condition.@@paulmilenkovic178
Re: NG Brake. Here’s from an Air Facts article by Mr. Jeff Hill about the Convair 880: “The 880 was the only plane I ever flew that had nose wheel brakes. Several conditions had to be met for them to operate: the nose strut had to be compressed, the wheels centered, and both brake pedals had to be depressed together. There were weight reduction penalties if it was inoperative.” I also hope you cover in Pt. 2 about Boeing’s attempt to stretch it into a -300. I was an aeronautical engineering student at the University of Washington in 1973 when the -300 was in the Kirsten Wind Tunnel. IIRC they could never get the Cm - Cl curve to go the correct way. Also I imagine the 2 wheel MLG exceeded most runway bearing strength ratings.
I was FO in 727-200 in the late 80's and to say it was "engaging" would be an understatement. Great channel. Subscribed from Australia.
My father was a check captain on the 727 before That Year. Loved it.
Thank you! Would love to know more about what was behind the word ‘engaging’!
It was no A320 if this makes any sense? ;-)@@asobester
@@ansett-airlines- yup, the A320 will never have anywhere near the 72’s fatality rate. Welcome to the good side of progress….
Well I have experienced 6,000fpm descents a few times and that certainly got our attention. @@Pupda
When i was a kid i was invited into the cockpit in flight. I sat right behind the captain and everything i thought to ask jest disappeared from my mind. I just wanted to watch them doing their work and learn how to fly them.
I’ve been searching for videos like this, ones that really dive into the engineering and design choices behind aircraft and their relevance
Fantastic video Andras, looking forward to Part 2! Please consider using a close up microphone for recording, it would lift your presentation from very good to top notch😉
Thank you! And will do 🎙️😎
Before the 757, the 727 was the best all round commercial jet. As a kid, loved the rear stairs!
707!!
Northwest Orient 727, Bismarck, North Dakota 1976. Entering through the rear stairs. Aviation buff for the rest of my life. My sentimental favorite airplane.
It was a loud and memorable boarding from the from the back with the apu running in bad weather, The free umbrella allowance was actually useful 😅. I had the pleasure of flying with a factory fresh -212 from Paya Lebar, the former airport & present AF base - soon to be redeveloped 😮
My Dad flew the 27 for Eastern. Thanks for the very detailed video!
Nerver flown a 27 myself, but talked to quite a few former 27 drivers. None ever complaned about the aircraft, which tells you something. And asthetically, nothing in this segment of aviation beats it !
I flew in the 727 from Baltimore to Bermuda on US air many times phenomenally a good plane always a comfortable ride and Bermuda is really an aircraft carrier out in the Atlantic. You have one shot on that runway and the 727 handle it beautifully.
This is so excellent. The 727 wing, “undressing” for landing was an eye-opener for this then 11-year old boy in 1963. As I watched this I thought a camparo of the 727 and VC10 wings would interesting. Thank you for this fascinating 727 deep dive.
Thank you, glad you enjoyed it, more planned!
Amazing video, this felt like the most interesting lecture! Thank you, can't wait for Part 2
Glad you enjoyed it! 😎
Great video of the first jet I flew in the mid 90’s. Thanks for the all the effort you are putting into these! Highly appreciated.
Thank you for the kind words, glad you enjoyed it!
I love watching these videos, not only for the content but how all the former 727 pilots, FEs and such add their own input in the comments. I've only just started flying jets (CRJ-200s+700s) and love to see the evolution of their design throughout their service. I wish there existed more literature on those planes, I can't seem to find much.
I flew for MGM Grand Air and Champion Air as a Flight Mechanic for 4 years on the 727-100 and 200 N502MG N503MG N504MG and N705CA thru N707CA i flew these planes all over the globe. In my 34 years as an aircraft mechanic the 727 was one of the most forgiving aircraft and easy to maintain, except for the the APU lol. 😊 I was able to witness some great pilots fly these airplanes to some really remote countries and landing strips as a flight mechanic, and there’s nothing that beats it in the sky, as far as ctuise speed of .85 is seen normally at cruise and low speed landings ability to land short conditions at some crazy airports. This is one of the greatest experiences I had as a mechanic early in my career.
Thanks for the video
Thank you for the insightful recollections!
RE: the braked nose gear, Concorde has a braked nose gear. Not used for actual braking, it's simply there to stop the wheels turning during gear retraction. I believe this was to do with the high gyroscopic effect of the wheels on the rather long nose gear. Note also, Concorde only had the brake on one wheel, the axle is continuous through the hub and both wheels are connected together (rather unusual I suspect). The nose gear is also used as the speed reference for the ABS system on Concorde.
This was FANTASTIC.....please do the 757 next!!!!
Thank you - I’ll add it to my to-do list 🤓
Excellent! Love the 727, DC9, historic Iconic beautiful aircraft.
Thank you! Might look into the DC9 for a future episode 🙂
Ah yes the DH121 and BAC 1-11 copies, yes very revolutionary....for copies.
Great video! Thank you! As a retired engineer and an aviation enthusiast I'm looking forward to 727 part 2 and other iconic aircrafts such as 747. Lots have been said about these airplanes, but no other video has the perfect balance in being interesting (informative and not boring).
Thank you Marcelo 😎
An excellent video, I flew both the 100 and 200 series for Dan-Air in the eighties. It was a Gentleman's Aeroplane' to fly.
Thank you :) Do you happen to recall if they were both fitted with a stick pusher?
Not too sure, they were fitted for the CAA accepting the 727 on the British register, but that was of course for the initial 100's . I flew G-BAJW a 100 series during base training at Shannon, and during the stall phase of training we certainly went up to the 'stick shaker', which was bad enough! I 'am beginning to think that the pusher had been disabled by 1985.@@asobester
I can remember flying dan Air 727 Manchester to Naples and back for a family holiday! Quite an experience for a kid whose only previous flying was a 747 over to the 'States. I can remember it feeling like 'real flying' when in the stack and dropping into Naples!
For all of the targets, this plane had to hit, and there were many) it did an amazing job. It was specialized, but also covered a broad range of general requirements as evidenced by its widespread adoption
Fantastic, well done András👍 .. more please! I'm really interested to learn about the balancing act between mission requirements, design thinking of the day, the technology of the day, and tradeoffs that give us the ac we see today. I'm particularly interested in why an ac looks like it does. Your blend of aerodynamics, design history, manufacturing and technology captures all this in an easy to understand way. Thank you!
Thank you for the kind words!
Extremely interesting...! The development history is fascinating. So much I haven't heard before. Looking forward to part 2.
I was a 727-200 ramp manager for many years, and jumpseated on them quite a lot.
The sight of that luxurious jumpseat was something...! Our jumpseat was a square metal panel that hinged out from the cabin wall.
We didn't have cooper vanes and never used jato assist :)
Thank you! I hadn’t realised that not all jump seats were made equal - interesting! I’m surprised about the lack of the Cooper vane (assuming this was later than the mid 70s) - was the rear airstair operational on those aircraft?
@@asobester yes, it was sop for us to lower the rear air stair at every stop, we had to, to get the tailstand out, which it was also sop to use. We were cargo, so probably they decided the odds of anyone trying to jump out were low :)
Oh I see, that makes sense! I guess the tail stand was specific to the -200F?
@@asobester yes I think so, we weren't operating the -100 in our area, but as I recall from training, the -100 didn't have a tail stand... with the -200, when loading full profile ULD's, there was always the danger (ie certainty) of a tail tip when you start pushing the containers to the back of the main deck...
The -200 actually can't fly empty, there has to be a ballast pallet in the 1st position if flying without a load... there was a small number of Canadian -200's with an extra long range fuel tank, that could be used as unusable ballast in such situations, but those were rare birds ..
Interesting! Sounds like the CofG envelope and related limitations will be worth a deeper look in Part 2.
The 727 was the first aircraft I flew on.and it was so loud (even with hush kits) that it sounded like it would crack open the very atmosphere itself. I lived near YSSY when the 727 still operated… not easy to forget.
My first flight as a kid was on a 727-100 and I loved it. I got to fly the 727 years later, but too late for the ostensibly squirrely -100. I did the yaw damper inop Dutch roll demo in a -200 sim (it was required training for the type rating) and it was eye opening. People I knew that did it on the -100 said it was way crazier on the shorter aircraft.
[Edited for grammar.]
Excellent video thank you. Very interesting re visiting the 727. Another thing I remember from my time working on them was that if the tail skid failed to retract the rear toilet door was to be locked out of service. The reason being that the wash basin waste water drain mast was located immediately forward of the skid. If this wasn't done, the waste water would accumulate and freeze on the skid. Not only creating more drag but also a hazard to people and property on the ground should it break free! The strange things that you remember!!
Thank you. And I cannot tell you how much I love the sorts of tidbits you just shared 😎. Aircraft had so many weird system interconnections like that, even before they had millions of lines of code on board!
I flew the 727 for years and never knew that (or forgot it decades ago)! Of course, we didn’t need to memorize the MEL, but if I’d encountered that I probably would have remembered it.
Thanks for the comment!
[Edited for spelling.]
I was a mechanic for the 727 at PSA San Diego maintenance. Our aircraft had nose brakes to increase the take-off weight on short runways. The nose brakes only worked during MAX braking. We would change them every few years for overhaul to knock the rust off. Another point is the aft airstairs. The 100 was hydraulic operated and could be opened with no power on the aircraft. The 200 was the same but had a blow down bottle to right the tail for emergency exit. The blow down bottle would break off the DB Cooper mod. On the 200 the DB Cooper mod was just for show.
Was the rust due to the rarity of pilots selecting MAX? Re DB Cooper - I had never really thought this through, but the vane does indeed look somewhat flimsy.
Interesting to learn about S ducts and fan blade harmonics. In the 1980s, my friend's father studied S Duct designs at Boeing. I see he authored papers on S-duct inlet-diffuser configurations.
Really enjoyed your 727 video and look forward to more installments.
Your video brought back many memories.
I flew the 727 for American Airlines as an engineer and first officer.
We had three -100s with nose brakes, these were for landing at STT
( St. Thomas ) before they extended the runway.
That airplane loved to go fast, we regularly would cruise .84-.86 and if
we were in a hurray we would push it up to .89 (MMO:.90).
Landing was always a challenge. It’s very stable until you get to about
12 inches, then you had no idea what it would do. Everyone had their
own technique, retarding the #2 engine to idle at about 10 feet, leaving
#2 up and retarding #1 & #3. Light weight landings were the worst.
I’m not talking about bone jarring, pull your pants up landing but we
always wanted a “grease job”.
Thank you for the interesting insights! Someone else also commented on landing being a challenge - from your description it sounds like perhaps ground effect suddenly changed the lift coefficient…? Do you happen to recall whether this was with Flaps 30 or 40? And did the choice make a difference to the handling in the last moments before touchdown?
We were restricted from flaps 40 unless for emergency, the only exception was the three -110s used for STT.
I must have tried every technique, so did everyone else, seems like my best landings were when I tried to
"roll it on" pushing forward right before you thought it was going to touch down. That would have the effect of raising
the mains a little. The mains were so far back if you increased pitch you would drive the mains into the ground.
They were the most challenging when they were light.
The one thing you didn't want to do was land in a crab. The fuselage would flex enough you could "drop the masks".
@@asobester
I find it very strange that several pilots referred to landing the 727 as 'challenging'. Landing that aeroplane was so easy, it was so stable on the approach even with strong crosswinds (with two rudders) and with 3000 lbs fuel flow on each engine, it would just 'cream' on to the runway marks, I did find that quite a few pilots were a little wary of the 727 especially the stall characteristics, and its speed. I think its reputation went before it, but provided it was flown, within the confounds of its envelope, it was just like a Cessna 150 on steroids.@@asobester
Thank you Andras!
My first flight as a child was on a 727-100 (I remember the center cabin galley), and I loved it. I went on to fly the 727 years later, but only the -200 series. I did my Dutch roll training (required for the type rating) in the -200 sim; people I know who did it on the -100 say the -100 was a wild ride compared to the -200, and the -200 required precision to recover. I never flew the aircraft with nose gear brakes, autospoilers, or a stick pusher. The chined NLG tires I recall well; the DC-9 series also have them. We were prohibited from using flaps 40 unless the Captain used his emergency authority. I did it in the sim but never in the plane. It seemed pretty draggy as I recall.
My recollection of flying the 727 was mixed, honestly. I flew it in the twilight of its years and have always admired the engineering of its wing, in particular. Watching that thing unfold is still amazing to me! I don’t recall you specifically mentioning it, though someone else did in the comments: the 727 could get down better than any aircraft I’ve ever flown; modern aircraft are so slick by comparison they they are very challenging to descend in certain scenarios (I’m looking at you, A-321!) For its day I think it was the 727 was the best short/medium range jet in the world, but I didn’t miss it when it was gone as so many others did. I admired it as a great piece of historical engineering; it had nice handling until about the flare, and except for landings was predictable. It could do some things really well (flaps 25 TO in LGA) and some things not that well (heavyweight takeoff in DEN in August), but it was solid and simple. It didn’t have great ergonomics and had some unintuitive systems quirks that led people astray on occasion (the brake vs. the hydraulic interconnect, for instance), but most of all I remember the noise. When I was a young FE and was flying with Captains who had been flying the plane for 25 years in all three seats, I got used to yelling, as they were deaf as posts. I normally wore earplugs in it (and the 737). I also remember the landings. The last couple of feet were like a random landing generator. You could think it was wired, and your teeth got rattled; the converse was also true. At my airline we had a saying that on 727 if you had one good landing you were good, if you had two good landings in a row you were lucky, and if you had three good landings in a row you were a liar. That’s not far off.
You did a bit of comparison to the L-1011, which is the only other trijet I’ve ever flown, and it is my favorite airliner of my career. It was so far ahead of its time (DLC, flying stab, etc.) that it is most worthy of your attention for its own video. I’m glad I got to fly the 727, but I don’t miss it; I miss the L-1011 every time I fly!
Magnificent video; I obviously subscribed, and have already forwarded this video to several friends who also flew the 727!
[Edited for spelling.]
Nice to see a properly scripted video. Makes such a difference.
Cusco Peru's airport at 11,500 feet asl, was no problem for the awesome, beautiful, sexy Boeing 727. Excellent video!
On L1011 vs DC10 choice, the L1011 and 727 are the superior configuration. Douglas knew this, but had other objectives:
- less design time
- less cost to build
- less cost for maintenance
- delivery before the L1011
They achieved this and caused the bankruptcy of Lockheed. Unfortunately there wasn't a big enough market for Douglas to recoup its investment and it never recovered financially. This left Boeing as the US airliner maker. Ironically Boeing's purchase of McDonnell Douglas led to its current financial woes as the financial types ignored the engineers
I love the passion and intelligence Professor Sobester who can take a subject like this and make it interesting. The 727 was the first jet airplane I ever saw when I was a boy in the mid 60s in Melbourne Australia and apart from its beauty I remember the smell. That distinctive smell of jet fuel, kerosene, that was oddly familiar as we had a hot water system that ran on kerosene! Keep the videos coming please and thank you for great video.
Thank you for the kind words!
Fascinated to finally finds someone who also goes by OEW normalised comparisons, I got drawn to it trying to decipher what went wrong with the A340, everyone blames the 4 engines, but nobody bats an eye at the absurd weight of the 345/346...
I wish I had seen this video before I did flight test work on the 727. I heard that the deep stall with Wallik (sp?) as caused by the FAA pilot flying saying, "I wonder how it will handle if we stall it with the spoilers open". We had a lot of fun flying all over the envelope. We flew as fast as anyone, except that one TWA (?) flight that went supersonic. We did aft cg stalls, but with the flaps up. Pitch stability was neutral at the highest speed. That wouldn't pass today, but the Boeing and FAA pilots thought it was acceptable, I was told. Boeing gave us guidance on sizing fences that we put on the FedEx hushkitted engine pylons to create vortexes land at the horizontal stabilizer high angle of attack to prevent deep stall.
My dad was an RCAF Comet 1 pilot flying out of Ottawa Canada. At the same time Eastern Airlines was flying their 727’s from Dulles to Ottawa every evening. I was always amazed at the differences between the two aircraft. Both were beautiful in their own way, but I recognized just how much better the 727 was just from watching them land and takeoff. In later years, I flew the L-1011’s for AC, and my dad at the time was an L-1011 instructor with AC. I absolutely enjoyed the aircraft, and even flew the Orbital Sciences aircraft in its previous livery with AC. I have heard rumors lately that the Orbital Sciences L-1011 is finally being put out the pasture, although I hope the rumor is not true!
Thanks for this very interesting and informative.look at the 727 and its technological marvels.
Thank you sir, glad you found it interesting. I bet your dad had some tales to tell about flying the Comet!
I’ve heard the same about the OSC 1011, but I hope that’s wrong. It was my favorite of all the aircraft I was able to fly.
[Edited for spelling.]
The 727 was the first aircraft i worked on out of A&P school. I recall being tasked to put oil in the engine and had no clue how to do that. The company I worked for did overnight checks on Mexicana's planes. I got to see the deactivated rocket pods as well as working on planes that still had nose brakes. Back in the day, finding contraband in the escape rope compartment and in the engineers desk was exciting. Those who know, know. 😂
Excellent video!
Thank you! Do you happen to know why they had deactivated them?
@asobester no, I never did hear an official answer, but would assume it was more hassle to have an active system then the use/benefits.
Thank you for giving me a new perspective and appreciation of the B727. As a 10-15 yr old, I flew in the Trident and 727 many times. I always preferred the Trident (patriotism?) as I viewed the B727 as basically an inferior copy. Thank you for giving me some insight into Boeing's creditable engineering theory.
Thank you for these deep dives ! Super interesting as usual, can't wait for part 2 !
Regarding nose gear brakes on airliners, I seem to remember that the Convair 880 had them also.
Thank you for the interesting addition to my list of aircraft with nose wheel brakes! I wonder if the 990 inherited them…?
@@asobester A pleasure to be able to help. Looking at an AMM found online, it seems that the Coronado did indeed inherit these brakes ! (Source: "Convair 990 Maintenance Manual" on Internet Archive, Chapter 32)
Rode on these many times back in the day.
I used to pick the seat right behind the the wing root so I could watch the wing transform itself during approach, and seemingly disassemble itself by the time of landing.
When the the spoilers came up, there was just a skeleton of the wing left.
As a pilot I never tired of this, and the 727 remains my all-time favorite.
Side note: Eastern pilots in the 80s flew these planes like the hot rods they were, and I saw them do things in the 727 you would never, ever see nowadays. Great fun:)
That flap system is a marvel, isn’t it. With computational optimisation techniques this sort of complexity is no longer required (the same cl max can be extracted from optimising the geometry of the flaps/clean wing), but it remains a thing of beauty one can admire like one admires an old mechanical watch in the digital age… Can you elaborate on what you saw them do? 🍿
Boeing allegedly had like 40 engineers working on the flap track designs.
@@asobester Swiss watch is an excellent comparison :)
Eastern? Ok: Houston to Miami, late at night, almost no one on board, and the crew in a really big hurry to get there.
We were going at a high Mach number - the engines were at very high rpm and there was a lot of slipstream noise.
As you know top of descent is routinely 30 minutes prior to landing, and as I watched the time and west coast of Florida go sailing by with no power reduction, I started to sit up and take notice. They stayed at cruise altitude until the very last minute, then yanked the power off while throwing out the spoilers and whatever else they had.
We sank like a stone, and I remember the distinct sensation of the ground lights coming up towards the airplane rather than gliding beneath it. After landing I stopped at the cockpit and asked the crew what the rate of descent had been. They just grinned and said they didn’t know because the VSI was pegged.
@@thomasbelmont810 Ha! Good practice for a depressurisation emergency descent :)
@@thomasbelmont810the ‘27 had the ability to descend at the rate a helo could auto-rotate. I recall vividly some fun rides when I had the privilege of working as a FE - nighttime freighters.
Truly a great aircraft. Not perfect but strong, robust and reliable. Regarding the ventral stairs, apart from allowing entry and exit, they were engineered strong enough to support the aircraft durning refueling operations in case incorrectly loaded fuel resulted in the aircraft sitting on its tail due to centre of gravity limits being exceeded.
What an outstanding, thorough engineering presentation. Kudos!
Thank you!
My goodness. I'm not a pilot, an engineer, or an airline professional, and I found this presentation completely captivating. I feel like I'm in an upper-level aviation engineering degree, with the best professor on campus. Will watch the sequel with interest.
Thank you for the kind words!
I may have missed it, but if you do another vid on the 727 you ought to mention the two-speed Stab Trim setup. And if you could record that wheel spinning at high speed during the numerous pitch trim changes between takeoff and a clean wing, you'd put a huge smile on the faces of a lot of old guys. Basically, with a clean wing you only had one (slow) speed trim. This was actuated through either the Yoke Swith or the one on the center pedestal. But with flaps out the yoke-mounted switch would command a VERY high speed response from the pitch trim. The reason was the massive high-lift devices. Their extension or retraction caused a BIG change in the pitch of the plane as the wing warped itself into a new shape. For an F15 or F20 takeoff, you had to make multiple and significant trim changes. I cannot recall exactly but there were multiple Flap settings that you had to go through to clean up the wing. F20, F15, F5, F2, (?) F1 and up seems to ring a bell....hell it's been a LONG time! You couldn't just go from F15 to UP after takeoff. You had to stop first at F5. And of course, you had to honor a different speed for each flap setting. And with no auto throttles (or an iPad and only a crappy wing leveler for an AP), let's just say that your hands and thumb were quite busy flying that easterly SID off Runway 13 out of LGA on an IFR day.
And unlike today's jets with ADSB, FOQA, and hideous overspeed warnings, the 72 had a very pleasant over speed clacker. If you weren't constantly bumping up against the clacker you were considered to be doing it all wrong.
Great jet. Great memories.
Great video, thanks for taking the time to record such a deep dive into this aircrafts design! Looking forward to the next one!
🙏😎
Wow, you’ve got to do the L1011 next! It was packed with innovation aswell.
What a joy to learn some of the design details of my favorite jet! 👍 I flew all three seats during my tour with FedEx! Most likely these two! First aircraft I flew as a Captain. Looking forward to Part II! 😃
Thank you for this excellent lecture! I wish my professors were that committed to their job
Thank you :)
What an absolute treat. Thank you for taking the time to make such detailed videos.
Glad you enjoyed it! 😎
MORE of these videos please! Fantastic job on this video sir. Very well done and you had my interest the entire time. Loved this! Thank you sir. Keep up the great job.
Thank you for the kind words!
Really well done! Worth the time watching every minute! Great book shelf!
Thank you, Mike!
Another great video, András. 🙂 Keep up the good work!
Thanks Joe!! 😎
Back in 1987, I worked with an MX crew in Fort Lauderdale that performed a 'B' check on a B727 owned by Pia Zadora (N888VT) - The exterior paint job was like that of a Zebra. The interior was done up like something out of The Arabian Nights.
Andras, What a wonderful video! Thank you. (Please forgive those complaining about the audio quality, small price to pay for such in depth information about my beloved '72!) Flew right seat one year on a -100 freighter, 5 yrs right seat on -100 and -200's, 5 yrs as a left seat on -200's. Would have stayed on till retirement, but after 9-11 my airline parked em. I called it "the taildragger of the jet fleet" as it was so unforgiving to any overcontrol or off airspeed on landing. Landing gear so far behind center of lift, easy to drive the gear into the runway if pitching up to arrest descent right before touchdown.
Went from the '27 to the 320, might as well have started flying an alien spaceship, the two had so little in common! Thanks again, wonderful video!
Thank you so much for the kind words! I hope you’ll like Part 2 too, hopefully out in a few days (btw, featuring a brand new lapel mic and hopefully improved audio! 🎙️😎). I got to fly in a 727 jump seat recently (still not quite believing my good fortune!) and I know what you mean about the distance between the centre of lift and the MLG - as we were landing, the Earth arrived much sooner than I was expecting it (fortunately the crew were not surprised like I was 🤪).
Amazing video, thanks for producing and sharing it!
Glad you enjoyed it!
Brilliant channel! All the technical information is much appreciated! Keep the great work
Thanks, will do!
Excellent detailed analysis...very enjoyable!
Thank you! Glad you enjoyed it.
What a great video. I plumbed briefly on the 727, on the special “Quiet Freighter” versions made for UPS with Rolls Royce Tay engines. A fabulous machine.
Thank you! Do you happen to know how many airframes got the RR conversion? I’m struggling to find a handy list
@@asobester I might have some documentation from the early days (I moved on from the 727 to the DC-8 and the MD-11-another trijet!-and now the 767), but I didn’t retain paperwork stuff very diligently. At least one source I find online said the QF modification was applied to 52 airframes, which is a number that sounds correct to me.
The biggest problem with the 727 was the nightmare of servicing engine number 2, way up in the air. That's why you don't see tail engines any more.
Excellent documentary and educational. Thank you for researching and creating this. 🤗
Glad you enjoyed it!
Fantastic video! I'd love to see you do a similar video on the 737 and the L-1011 or other heavies as well!
Thank you, I’m glad you enjoyed it! A second part to this is coming soon 😎
Great video! Thanx! 😊
We love a good engineering video. Thanks so much!
Glad you liked it!
Stellar content and presentation. Subscribed!
Very kind, thank you!
Love the aircraft. I flew the 200 all pax, all cargo, and the only -200 combi. The long body, wings, and tail are beautiful. One doesn't even hear the engines when you start up. When thrust is added for takeoff, there is only the increased sound of air conditioning airflow(and the altimeter vibrator clicking away). Same on the climbout with peace and quite....until 250 knots, then it gets loud as the airflow noise gets louder and louder.
Landings could be interesting. Go for a while with a streak of decent ones and then the inevitable firm one. Sometimes one would be expecting a firm one and would get a greaser. Many would say that you flare by pulling back on the control column and then push to roll it on, but it was really just a relaxation of the control column.
Remember, the nosewheel brakes don't necessarily get activated. They only operate when the brake pedals have been deflected beyond a certain amount(something like 50%) so that they are not being used unless they are really needed.
I saw a flaps 28 position in the cockpit shot. That means a Raisbeck noise mod which intentionally reduced max flaps deflection to reduce required thrust on approach.
As a passenger I really enjoyed flying on the 727's. Miss them.
Prof. Many thanks
Great video, one of the best I have seen on youtube. Thanks.
Wow - thanks for the kind words!
Amazing video! Keep them coming!
Thank you, will do :)
I flew on a Delta Airlines 727 from BWI to CVG in the late 90s it had winglets installed on the the wing tips. That jet looked sharp.
Excellent video, thank you for sharing! If I may, I would request a DDD on the B747 or Concorde.
Thank you! And thank you for the suggestion, I’ll give it some thought, though it is a big challenge trying to contribute something fresh on aircraft about which so much has already been said.
M-FTOH, a 1980 built 727 originally ordered by Kuwait Airways, now bearing an Isle of Man registration.
You do such a great job with these deep dives. I've learned a lot from watching them. I'm a big aviation nerd and am fortunate enough that I have a dream job for someone with such interests. I am the manufacturing SME on the 777x folding wing tip hinge in Everett WA. Keep up the great work. Cheers!
Thank you for the kind comment! I’ve been following the 777x folding wing tip with great interest, I had the opportunity to take a close look at one at Farnborough 22.
this is excellent material
Thank you!
My Gosh what a beautiful video by a highly lnowledgeable and capable person. Details I did not know explained!
Glad you enjoyed it!
@@asobester oh yes! And I would love to see one for the 757
@@TheAlf61I’ll put it on the to-do list :)
This thing is mint ❤
My Dad flew the 727 for Dan-Air, his favourite aircraft.
Awesome vid!
Thanks!🙏
Aaaah, the perfect video
🙏
Don't forget blown flaps were all the rage for military aircraft too, both the F-104 and F-4 Phantom featured blown flaps.
Good point, thank you.
The book on the shelf for Supermarine Spitfire looks like a Haynes owner's repair manual commonly done for vehicles. I look it up, and it's a thing! I had no idea they went beyond cars.
They do! Although unlike the car ones, this won’t tell you how to clean the spark plugs on your Spitfire etc 😉
First video I've seen from your channel. SUBSCRIBED. ☺️👍
Welcome aboard! 😎
I was a mechanic for United Airlines, our 727s did not have the nose wheel brakes. Not the easiest aircraft to work on, but in my opinion, the 727 was the sleekest looking of all the airliners out there.
46:53 There was a DB Cooper copy cat who did the same thing. Many people say DB is Flyod Mcoy. So twice the air stairs were used to parachute out with cash.
Interesting channel. Subbed
My Dad's 1st cousin worked on the 727 project in his long career as an engineer in Renton.
Also, want to hear about the “Hoot” Gibson supersonic spin out over Cleveland and what the aero forces were to pull off the slat. Thanks
One of the loudest jets in history!
Indeed! Loud in the cockpit too! I can’t tell you how many near-deaf 727 Captains I flew with as a new FE!
I don't think either of you ever heard a 707 water injection takeoff if you think 727s are loud. Western called them Whisper Jet.
An easy subscribe. Thank you
🙏
Flew out of ABQ in early seventies. JT8s were slow to spool but at about 30 MPH it really accelerated. Much faster than they do today.
Yes - fun push in your seat with acceleration G - forces ! Good times . Now , Boring to me -
Definitely a , No Go - No thanks Too bad .
The doors stayed on, ahead of it's time
The first aircraft to completely deconstruct its wing and somehow stay aloft.
When were wings with conventional airfoil shapes, succeded by the newer Whitcomb shapes?
Ive loaded to many 727s frighters to remember, 100 and 200 veriants owned by DHL and Air contractors.
I flew for about 10 years in the B727, I think it was the best among the planes I have flown.
Still in my dream.