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Anonymous
this is one of the most interesting planes that i have ever seen. its turbofan engines push the super fast exhaust over the wing to increase lift. that makes a lot of sense right? then why isnt that technique more widely used in aeronautics?
sorry bout the shitty image. i would love to see more in better quality. thanks everyone.
>> Anonymous
wow, fuck me. i forgot to include the name. it's an antonov an-72/74. it is mostly in use by former soviet nations and israel.
>> Anonymous
don't know. perhaps exhaust air is pretty aggressive on the wings?
>> Anonymous
>>349005
maybe, it could make the material weaker, so that type of planes probably don't last long or the wings have to be replaced oftenly.
>> Anonymous
>>349047
wings aren't replaceable parts. oops, it's overdue for an oil and a wing change. nope.
>> Anonymous
>>349048
obviously it's not like that. but they can sure be replaced after a while.
>> Anonymous
Exhaust air is Highly turbulent, which in facts decreases the amount of lift you can get from it.
>> Anonymous
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I'd guess that the exhaust doesn't so much damage the wings so much as it just deposits tons of crap on the top surface, which would be ugly, for starters.

Also, I feel like it must have a tendency to nose forward with the engines mounted so far off axis. Probably just requires an extra touch of trim, if it exists, but I'd guess its there.

And, my little tidbit that uses the word "technique" a bit broadly: I know that the extra lift really only comes into play during low-speed maneuvers, such as take-off and landing, and actually the principle that makes this work, the Coanda effect, is the same principle behind flaps on other aircraft.
>> Anonymous
good call on the coanda effect:

The Coand? effect has important applications in various high-lift devices on aircraft, where air moving over the wing can be "bent down" towards the ground using flaps and a jet blowing over a curved surface. The flow from a high speed jet engine mounted in a pod over the wing produces enhanced lift through turbulent mixing that does not occur above a normal wing. It was first implemented in a practical sense during the U.S. Air Force's AMST project. Several aircraft, notably the Boeing YC-14 (the first modern type to exploit the effect), have been built to take advantage of this effect, by mounting turbofans on the top of wing to provide high-speed air even at low flying speeds, but to date only one aircraft has gone into production using this system to a major degree, the Antonov An-72 'Coaler'. The McDonnell Douglas YC-15 and its successor, the Boeing C-17 Globemaster III, also employ the effect, though to a less substantial degree. The NOTAR helicopter replaces the conventional propeller tail rotor with a Coand? effect tail.
"wikipedia"
>> Anonymous
look up blown flaps, it's a technique where air is forced over the whole wing.

The relatively narrow thrust of the engine when just bolted to the wing like in the An-72 is not as effective. IIRC, another major function of mounting the engine that high was to avoid FOD ingestion problems when operating from unprepared surfaces.
>> Anonymous
The engines are up there to reduce the risk of debris getting sucked into the fans while starting/landing on a provisional airstrip. This type in particular is used to haul tourists close to the north pole and back.