N243NW From United States of America, joined Jul 2003, 1491 posts, RR: 21 Reply 5, posted (9 years 6 months 2 weeks 1 day 8 hours ago) and read 2452 times:
Why no two wing mounted/two tail mounted jets?
Have there been any designs for a jet with two wing mounted/two tail mounted engines?
The question that our friend Jessman is asking is not "Why aren't there any jets with all four engines on the tail?".
I assume the aircraft would just be too complicated with the configuration (different styles of pylons, nacelles, etc.) and too hard to maintain (the mechanics would have to check both the wing-mounted and tail-mounted engines, however it seemed to work for the DC10 & L1011). I don't, however, see any significant advantages for this configuration compared to others, but I have turned the idea over in my head more than once before. There is also the chance that by the time that any aircraft manufacturers might have thought of this (if they ever did), the commercial jets became more simple and efficient with only two engines. Any other ideas or details would be appreciated, as I'd also like to know of your thoughts or facts!
Jessman From United States of America, joined Jul 2001, 1506 posts, RR: 8 Reply 6, posted (9 years 6 months 2 weeks 1 day 8 hours ago) and read 2401 times:
I must admit, I did completely forget about the four tail mounted engines. I have never seen one of those aircraft in real life.
But that does make me wonder, are the two inside engines hard to get to? It seems like they would be a problem to maintain.
Jetguy From , joined Dec 1969, posts, RR: Reply 7, posted (9 years 6 months 2 weeks 1 day 7 hours ago) and read 2309 times:
There have also been 4-engine aircraft with the engines mounted on top of the wings - there was an experimental USAF transport in that configuration. I don't remember who built it, but I believe that it's on display at the Pima Air Museum in Tucson. The Gemans also built a small jet with two pod mounted engines slung above the wings - a Fokker I believe. I think that designers have hung engines just about anywhere you could possible hang an engine over the years. Wasn't there an early USAF bomber that had its engines pod mounted on the forward fuselage?
Coronado990 From United States of America, joined Oct 2003, 1590 posts, RR: 2 Reply 9, posted (9 years 6 months 2 weeks 1 day 7 hours ago) and read 2265 times:
Regarding the two engines on the wing, two engines on the tail design: I would think the engines mounted on the sides of the tail would tend to suck in the exhaust from the wing mounted engines. Probably not a good thing. The DC-10 engine sat up high enough to avoid this problem.
Nudelhirsch From Germany, joined Oct 2003, 1438 posts, RR: 20 Reply 11, posted (9 years 6 months 2 weeks 1 day 2 hours ago) and read 2148 times:
I'm not an expert in aircraft design. I could imagine, that the engine position is actually influencing flight stability and flight behavior of the plane.
Seeing the two-eng wing-mounted as a "normal" way, 4 on the wing still pretty normal, DC-10-style to increase vertical maneuverability (is this a word???) by a third centered thrust. I read in a book, that this layout helped a crew to land a DC-10 wihtout rudders, to control bank by the wing engines, and descend and levelling out by the tail engine.
I also read, that there is an effect, which uses the exhaust stream of the engine to flow over the wing, creating more uplift.
It probably also depends on engines on the market and their power. If, like Coronado mentioned, exhaust in inflow wouldn't be a problem - what sense would it make to mount 4 engines to a 737 - two on wing, two on tail - would probably be great looking, but probably no sense in economical ways.
See also the thread about why the BAE146 has 4 instead of 2 engines...
The DC-10 had pretty big engines, and placed in a triangle, which would, like mentioned enable the crew to use the the engines for steering. I don't think, a "4-engine, 2-wing 2-tail concept" would provide these effects as well.
Just my stuff, I really am not an expert, this is what I gathered by reading and thinking. Interesting thread though!
Jessman From United States of America, joined Jul 2001, 1506 posts, RR: 8 Reply 13, posted (9 years 6 months 2 weeks 16 hours ago) and read 1858 times:
For the design I was thinking a jet along the size of a A340. It seems to have engines that would be small enough to be mounted onto the tail.
With all the different places designers have put engine, I would have thought this would have been tried.
I suppose the exhaust thing could be a reason.
Some pretty cool pics have been put up on this thread. That's great.
Mandala499 From Indonesia, joined Aug 2001, 6175 posts, RR: 74 Reply 15, posted (9 years 6 months 1 week 6 days 15 hours ago) and read 1594 times:
Engines on the wings = Balanced weights centered around the wing/cg/cl.
Engines on the tail = Nose heavy... resulting in long nose and short tail...
Combination... have you compared the DC10/MD11's wing position relative to the overall body with a 777 ? Now slap another engine on the tail and see that wing move further back... In the end, you might aswell have 4 engines on the tail, or on the wing. Not to mention the maintenance complications. 2 engines with all the connections on the top, and 2 engines with connections to the side... Hmmm, sounds like a nightmare to me...
And we haven't even gone into the potential use of cabin space if the engines are on the wings!...
When losing situational awareness, pray Cumulus Granitus isn't nearby !