Why are the 737's Engines Flat?
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- Опубликовано: 17 окт 2019
- Boeing's 737 is far from the most distinct looking aircraft on earth - some might call it a plain looking plane. However there's one key distinguishing feature of the 737 that does stand out: its flat-bottomed engines. Why are they designed that way, and how does it affect the 737's aerodynamics and efficiency? Let me explain...
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Eventually, though, Boeing is procrastinating almost 40 years with solving the problem of the 737's low clearance from the ground, which led to changes in the location of the engines on the 737 MAX, which in turn led to a tendency of the plane to stall, which led them to develop of software band-aid, which led to 346 dead people. This whole thing reminds me of something I've learned at 3rd grade, when my teacher and my mother spoke about these ridiculous, cheap thing the school installed on all doors to prevent them from slamming, which had to be replaced shortly after being bought and installed, leading my teacher and my mother to agree that "cheap solutions end up being the most expensive ones".
Omer Shomrat I wrote a paper on the situation with the max and the mcas system It was outdated to what I would do know but dam it weird
Mucho tecto
that's really interesting take
It's not just the MAX. It's every single newer 737 dude to the forward placement of engines which causes instability at low speed
That means design hitting it's limit, and now look at MAX.....
Tile to redesign that 737
All this multiple add on and avoiding revamping of the landing gear ended up into Max debacle
Ibrahim Makumba no... it didn’t. It had nothing to do with that.
Pat hampton it kinda did. Higher bypass engines were too big to mount without mounting them forward, thus creating the pitch up attitude.
@@matthehat True, it did influence the design. Airbus didn't have this issue because the A300s were originally intended to sit higher off the ground. Therefore, Airbus could afford to compromise a little bit of space between the wing and ground while Boeing took the lazy approach, which cost them dearly.
Same with the DC 8 tall landing gear and they could stretch the 8 low gear on the 707 could not stretch it because of tail strikes so they had to make the 757
Me, absolutely know nothing about planes :
"Oh yeah, why are they so flat?"
XD
I am a airplane enthusiast
And don’t fly them (yet)
@@cobyexplanes meaning
@@itsnaveenn are you an Indian
@@itsnaveenn X represents closed eyes while D stands for an open mouth.
Engine manufacturers only make the turbine engine itself, not the nacelle. The nacelle is part of the airframe and is the responsibility of whoever manufactures the airframe (Boeing). Just a small mistake for an overall solid video.
Not solid video. Any video mentioning 737 should show condolence to the victim's family of Boeing's practice of profit over safety.
I once flew on a 737 with those old cigar shape engines to Honolulu. I remember this because the airbrakes were very complex with the rear 1/4 section of the engine cover on hinges. They slam open in a clamshell shape to divert airflow forwards to help with braking. This must have been one of the last 737s with that because the very next year, they all went away and were sporting much wider engines.
Lucky you, how did those engines sound??
I’ve seen a lot of your videos on my recommended page over the past week or two and I’ve watched probably about 5 or 6 of them. Honestly this is some good content you put out. Well informed and very well spoken. Congratulations, you have hooked me in to be a subscriber! 😆
You deserve way more subs
Thanks Tim! I’ll get there eventually - it’s hard to grow a RUclips channel from scratch
If it helps Coby I've been sharing the videos on facebook and with friends!
@@alphamalegold1 Ya it actually helps a lot! The more you share the faster the channel will grow
Ive been sharing it with my friends and the entire water polo team
@@cobyexplanesfan1238 Fireeeee
Ahhh coby Explanes does it again great video mate!
Thanks! This will be the last video with the old video camera so they’ll only be getting better
Correct me if I’m wrong but doesn’t the a330 engines have this too?
They are much more subtle, but RR powered ones do, yes :)
THe p
Tks for your video Coby Explanes
thanks for watching :)
0:12 I've actually flown on that exact Southwest plane! Smoothest landing I've ever had too, shook the captain's hand afterward.
You got the story exactly right. They maintain ground clearance by rotating the gearbox a little bit creating the chipmunk cheek effect. However, the 737 engine supplier is CFMi international, not Safran. CFMi is a consortium with two 50% partners, GE and Safran.
Coby: No key feature of the B737.
B737 angled vertical stabiliser: Am I a joke to you?!?
lmao fair enough
You can also find that feature on those Embraers too.
Omg thank you for answering this!!!!! I’ve ALWAYS wanted to know this
The angle of the slant at the base of the vertical stabilizer is also iconic of the 737. The empennage is very unique in the 737 along with the engines. No other aircraft have that angled base on the leading edge of the vertical stabilizer at the base. Maybe a video on that would be in the future?
I was asking to myself this question since 2010 , now I know what is the answer 🙂
So , thanks for explaining these information
I am too lazy to do that lol
This is google
Can you do a video dedicated to upcoming planes or concept planes. Also more plane vlogs would be epic. Best chanel ever
Most definitely can do this. Are you interested in like near future airplane concepts like the 797, or far future concepts that won't be launched until the 2050s?
Also more vlogs coming soon ;)
797 and possible more
Like boom airliner, or the Boeing hypersonic.
On the routes I fly most I have a choice of 737 on one airline and A320 on another. The former feels old, small, tight and noisy. The A320 however is a different class, so roomy, so modern, so quiet (eerily quiet) even at the back where I normally choose to sit.
I see you haven't tried the Boeing Sky Interior
I flown on the A320 as well and it was still a noisy plane just like with the 737 and the smaller passenger jets I flown being the MD-80, 717, Bombardier CRJ, and Embraer E-Jets.
This video was created months before the 737Max desaster, but it pointed exactly to the point where the 737 has reached the end of the line. To use engines with an efficient high bypass ratio, you had to move them forward and up, with all the problems resulting from that.
And of course it still stays an old metal bird, generations away from a 787 design.
Where can i get the merch?
Thank you!! I have wondered this for years. Now I know why they are like that.
Something wrong with you if you need this video to know why. This feature/practice killed 400 people, that is why.
Dude, another 737 unique design only seen on the Classic and NG models was the tail cone outlet. The Max went to a conventionally straight configuration while the prior models were upswept, take a look. Long timers at Boeing can call it out from a very long distance.
You truly deserve more views!
Thank you! The views will come don't worry :)
What's up Coby? Thought I would touch base with you. I remember seeing a comment that you had never saw the movie Top-Gun. But I see that you got to see Top-Gun Maverick. Well I saw it today,06-05-22 Sun. The movie is absolutely wicked! I was surprised that the movie is one hellava of a tearjerker. I really enjoyed it! I will see it again. Take care bro. Your friend,Lee Crolley, III
You got the reason mostly right, except FOD avoidance was a major driver. You got a few other details wrong... General Electric and Safran have a joint venture called CFM that makes the engines for the 737 MAX and NG. Also, Safran does make Nacelle components for airbus, but not for Boeing. The 737 MAX inlet was designed and fabricated in Charleston (Ladson) South Carolina by Boeing...
Ok this is epic
I think so! ;)
Already hopping on the username bandwaggon before he blows up I see...will be a smart move when he has 100,000 subscribers
@@alphamalegold Haha I didn't even notice this I'm glad I've got some big fans out there
Yes
@@cobyexplanesfan1238 love it
Interesting video.
So the 737 hit its design limitation long time ago, way before the MAX was designed. Boeing knew back then that they can't put a bigger fan in future design but decided to keep the 737 as is. Then with the MAX, computer designed a patchwork plane that needed computer flight aid to fly.
That's a big oversimplification. For one thing, the 737 is just about the only plane still being made that DOESN'T require a computer to fly. Everything else is fly-by-wire, meaning the computer flies the plane and the pilot tells the computer what he would like it to do. The 737 is still controlled with mechanical cables and hydraulics. The system you're referring to, MCAS, is an augmentation system that spins the pilot's trim wheel to prevent a stall in case the pilot does something he's not supposed to do (in this case, add a bunch of power to try and clear up a stall). To be clear, in any jet airliner with under-wing engines, adding a ton of power while at stall speeds is going to pitch the nose up and cause problems. The reason this became a particular problem on the MAX is not really that the engines are positioned differently (being higher and further forward is more stable actually), but just the fact that the engines were significantly more powerful. The same engines are used on the A320neo, and the same effect occurs, but unlike a 737 that airplane has always been highly augmented, so pilots of the Neo don't have any additional systems or different characteristics to learn. With the MAX, because they were adding this augmentation for the first time, pilots would need to know about the change. But part of the design requirement for the MAX was a shared pilot type rating with previous 737s; this was dictated by the airlines due to the A320neo having achieved a no-training update. The goal of MCAS was not the make the MAX flyable, but to make the MAX respond like an older 737 with less powerful engines. Boeing got into trouble because for some stupid reason this system trusts a single AoA sensor alone without cross-checking other sensors, meaning a failure of this one sensor can lead to unneeded action by MCAS. A pilot trained about the system would be able to figure out the problem quickly and stop the trim wheel physically with his hand, but there was no such training. Although really, anyone flying any 737 MUST know that trim has more authority than the yoke, so any time the trim wheel is yeeting forwards, a pilot with a brain should know to stop that thing immediately, whether it's a MAX with MCAS, or a vintage -200 with a short circuit in the electric trim switch. In my opinion the whole thing should be easily fixed, either by retrofitting a second AoA sensor, or by reprogramming MCAS to reference other sensors to get a more accurate picture of whether the airplane is stalling. But it's turned into a big hoopla with the public demanding big giant changes, on the assumption that it's a big giant problem with the design of the airplane. It's pretty telling that, even during the grounding, there are still thousands of orders for the MAX because airlines know that the basic airplane is very good and that this problem will be pretty easy to fix once the mountain of government paperwork gets sorted.
@@JETZcorp Wow. Thank you for your insight.
@@2be1withU ME' EYES!!!!!
Just found this channel it’s awesome also you should make a discord (I can help if you want 😎)
Thanks! Glad you're enjoying. I definitely will start a discord at some point, but I'd like the community to grow a bit more before that; I don't want to get ahead of myself. At this point I think I need the most help spreading the word about Coby Explanes, then the discord can come after :)
Coby Explanes t
The vertical stabilizer, the plane's low stature and the shape of its nose are key giveaways that it is a 737.
2:39 which engine has bypass ratio of 30 ::1 any example please ?
Wouldn’t a lower ratio be more efficient? It seems to me that more air going around the turbine is not good, or am I missing something?
I like both A320 and 737
When I worked at the airport I figured it was due to the plane sitting lower to the ground and they didn't want them to catch on anything as opposed to the higher sitting planes.
Isn't the absence of main landing gear doors an even more defining feature of the type?
Coby, the second thing at the 737 is that it has a Very Pointy Nose and it V shaped side windows
You can’t have this conversation without talking about the biggest factor, wing-low crosswind landings. Notice how the flat spot on the bottom has dihedral. Is that because cones closer to the airplane are smaller?
My favourite plane is the Boeing 727 tri-jet :) Beautiful performance and the 3rd engine makes all the difference.
LOVE the 727! Don't think I'll ever have the chance to fly on one, sadly :/
@@cobyexplanes the best I'll get is studying it for ATPL's :'(
I remember going on one as a kid. I swear I haven’t been in another passenger plane that matches its runway acceleration pushing you back in the seat. But I am comparing with a memory from 31 years ago.
@@alexs3187 They sure don't make em like the used to...
Coby Explanes nope! I still remember the meal on that one-hour flight too. Shepherds pie! Now you just get a packet of pretzels. Though one thing I am grateful for one change. You don’t pay $800 for a one-hour flight anymore.
Thx coby for making us learn, Pls Use this Background music pls its cool
You lost me when you said ''737 looks pretty unremarkable''. It is a pure beauty along with 777-2000.
Another key feature of the 737 is that straight bit before the upward sweep of the tailfin...
So if Boeing managed to do this with the 737 NG, how come they didn't just lift the 737 MAXs engine bottoms higher and making it flatter rather than lifting it higher on the wing leading to the instability that requires MCAS?
Good question.
Efficiency. The bypass ratio would be smaller which would make it less efficient
Well, they did. But at some point you can't make the nacelle more misshapen without affecting performance. In order to achieve their desired fan size, they had to lift the engine
Well there's only so much they can do to misshape the nacelle without it impacting performance. At some point, they'd have to make the engine smaller, which would definitely impact the bypass ratio
@@80sfreak14 wait i dont see how lifting the bottom higher lowers the bypass. I thought bypass was only dependent on fan size
The vertical stabilizer is unique ,no other aircraft in the world has a design like it. great video though
Except the E-Jet family of course
ironically I have probably flown on the 737 the most out of boeing's fleet, however my favourite plane has to be Airbus' A320neo. I took a flight on that plane for the first time this year flying with BA and the impeccable smoothness of the flight, i was so comfortable and makes me not want to fly on a 737 anymore!
i think Coby ment the most popular commercial airliner is the 737, cause i think the Cessna 172 is the most popular aircraft.
So this is what happened with the max?
No features that give it away?
Apart from the tail that breaks angle and tangents into the fuselage, the pointy kinda flat sided nose and that low mean stance... ;)
I recently saw an Antonov with jet engines mounted above the wings. Why didn't such a design gain popularity, with clear advantages like high ground clearance, better debris protection, easier underbody access for cargo for example?
Because it’s only suitable for aircraft with STOL performance requirements, NOT passenger or other commercial aircraft. This engine design serves a purpose and has disadvantages and is unsuitable for an aircraft like the 737 or others
Boeing should have mounted them like a 727 or MD80.
Some E-190s have oval inlets
This video was made one day after my 16th birthday!
I'm happy my assumption was correct, just thought it was using GE Engines
Thanks for the post.I learned some things I didn't know. The CFM56 is a 50% GE 50% Safran partnership (CFM International) GE made the compressor and high pressure turbine. Safran made the front fan and low pressure turbine. Originally Boeing approached Pratt & Whitney, the manufacturer of the JT8D engine. Pratt passed and CFM Int went on to produce 30, 000 CFM 56 engines (2016).
737-800 wing-tips? They’re pretty unique.
Would you guys fly in a B737 MAX now , after all the info here in the comments. Informed decisions , choices, choices.
I would deliberately choose to book on Airbus A320 instead.
Like their interior designs, 18 inches economy seats, quieter planes cabin, ergonomics, safety.
I'm still not completely sure why making the bottom flatter fixes anything. Sure it increases ground clearance, but the fan must be small enough to fit into the narrowest part (bottom to top), so any extra width is pretty useless since the fan can't be any bigger. Why not make it round and smaller?
The bottom is flat because all the hydraulics have been moved to the side. Fans in round engines also aren’t the diameter of the engines nacelle but also smaller to have space for hydraulics. A bigger fan was chosen as it is more fuel efficient and can have a higher bypass ratio
the a330 Rolls Royce engine also has flattish bottoms on the engine
So, we can call the 737s we have today, 737NEO?
Francesco Bellringer thats airbus
Except for when the MAX put the engines higher and more forward than previous generations... Which caused the creation of MCAS... 😳
CFM-56 vs. runway water ingestion
Why would anyone wonder whether the engine fan blades were misshapen?
Personalee i like the B737 MAX 8 Southwest
If you see the bottom of a 37 with the gear up, it's also pretty obvious
Yes, the lack of doors over the retracted landing gear is very iconic.
0:10 What about the windshield? Only Boeing aircraft have windshields in that shape.
You’re right that only Boeing have such a shape, he was taking about 737s though and for those the shape isn’t a clear hint that’s it a 737 as those can also be found on the 707 and 727
Boeing needs to dump the MAX and go back to the 800. The Max is not a stable airplane.. The trim keeps going nuts.. The back horizontal stabilizer needs to be out further like a few feet added to it each side but no they will find a cheap way out.. But by doing the cheap way it will put a bigger load on the tail much bigger.. It would be a matter of time before the tail would fail..
Well it'll be hard for them to do so since 1, there have already been 5000 MAXs ordered and 2, the CFM56-7B engines for the NG are no longer being produced. It makes much more sense for Boeing to take some time to redesign the MAX for aerodynamic stability than revert to an obsolete plane
The MAX is plenty stable if compared to the a320neo they both have the same problem so whatever happens t othe max needs to happen to the neo too
@@cobyexplanes Effectively true, but one technicality: CFM56-7B engine production does continue in low rates for ongoing production of military-derived 737NGs (P-8 and AEW&C). Obviously not nearly enough to restart NG production, though.
0:14, wait Coby there is a second feature about the 737, its pointy nose
And no doors covering the landing gear when retracted! 3:38
The pointy nose can also be found on the 707 and 727, so no key feature of the 737
Aaaaaand the saving cost mentally ended up with lifes lost and a huge reputation damage
Bro’s engines are flatter than that girl in my class💀
when the engineer doesnt know how to make higher ground clearance
The 737 engine intake reminds me of a grouper fish with its mouth wide open because the bottom is flat.
hahaha I see it
I think if the gear fail they make it flat
haha perhaps XD
When they are round that’s when you worry
Coby you look and sound like Sheldon from BBT.
ugh
The First B737 was the B737-200
Can’t they just put the engines over the wings and add a software for handling of the jet? Oh Wait, we just need an airframe that’s not infact 50 years old.
Maybe they instead should have just put bigger tires on the landing gear?
Where to put these tires when retracted? There isn’t more space in the gear well and it isn’t possible to have more space without completely redesigning pretty much the entire fuselage
Boeing then: 737 cannot change gears for cfm because it would be costly.
Boeing now with 737max: fuck.
Captain joe explains it much better.....
Indeed sir
@Captain Joe is the best of explainers
However, this man isnt bad
His namez Coby
R.I.P Kobe😭😪
Heartbroken I'm such a big Kobe fan
Boeing definitely have some flat engine*rs.
Plurals don't require an apostrophe. Just saying.
oops you're right, I wasn't an english major haha
@@cobyexplanes You are however very good at presenting your videos. I want to thank you for your work and I wish you all the best for 2020
It's not a plural though, it's possessive. The 737's engine. The engine belongs to the 737. There is no plural in this context.
Ubiquitous alright, like the B727 was to the 60s to 80s.
And it was also the reason why 737 MAX happened!
It is bekos Ryanair
What? Unremarkable? I feel insulted! That's a beautiful, iconic plane! Definitely more striking than the A320 family!
A320 is safer
@@fredharvey2720 they're both safe
@@themindset3329a320 seats wider, better humidity and quieter
Why 737 so famous
On the news, it's says
*737 crash land*
Somebody left it sitting on the ground in the hot sun
3:41, Ye Coby but the re-work would have saved the MAX from the crashes.
It's because they were dropped as babies.
When they out an option, there's mcas. Shame on you boeing
737 bankrupted Boeing. Morally and financially.
It's a truly ugly airplane in a world of modern looking types this looks like a dinosaur
I prefer Airbus. Boing sucks