Expert: Paul Soderman - 6/22/2006

Question
This might seem like a strange question, but I have to ask.  As you will be able to tell my knowledge of aeronautics is somewhat limited, but I still need to lay this suspision to rest.  Is it possible to create wing lift by using air from the thrust of an engine (passing over the wing)?  If so, how efficient would it be to use that thrust to lift a wing as opposed to simply using the velocity of wind?

Answer
Sean

This is not a strange question.  Both NASA and the Japanese have built and tested over-the-wing blowing aircraft.  High speed flow over a wing reduces the pressure and creates a lift force no matter the source.  I forget the model numbers, but they proved successful for short takeoff and landing aircraft.  A number of problems emerged.  1) The noise and vibration induce by jet flow over a wing is very significant.  2)  The exhaust caused the wings to turn black, which is bad for customers.  3)  Forward speed is still needed, so jet thrust alone does not do the job, but certainly helps the lift from forward speed.  As to efficiency, I don't know, but at this point the design has remained experimental, so I assume the economic and factors above were not overcome.  The situation may change if long airstrips are not possible.

Paul