Re: Jet Engines above the wing

From:         J.M.Butt@aeromech.salford.ac.uk (The Time Technician)
Organization: University of Salford
Date:         09 May 96 12:50:14 
References:   1 2 3 4
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One minor point, passengers would generally be less willing to travel on an
aircraft with above-wing mounted engines, it would be, what's the term, less
aesthetically pleasing? People are used to seeing dropped engines(in the
West, anyway), and would generally be less trusting of the aircraft if the
engines were mounted above the wings.

As for Mr Peters' comments about noise, this is true, but only for low
winged aircraft. High-wings would partially shield the noise and actually
make quite a significant difference, compared to dropped engines, and also
have much better aerodynamics, in that form drag is significantly reduced.
The maintenance factor comes into question then, though.

Upper-surface blowing does actually increase the Lift Coeeficient of the
aerofoil, which could come in handy for short runways etc, but has been
stated by another user, jet flaps have the same effect, with much easier
maintenenance for the dropped engine.

Unfortunately, there is very little information currently available on the
effects of upper-surface blowing, no real study, to my knowledge, has ever
been undertaken. I have just been involved in a design group for a new
aircraft, and we did actually use a high wing with upper-surface blowing,
but this was mainly because of the market we were aiming at. We
'approximated' the effects due to lack of any real information on how to do
it. Might make a good thesis for someone...... Like any other design, it
does have its advantages - ground clearance, reduced noise, improved
performance etc (as well as disadvantages).

See ya.

The Time Technician

E-Mail:AMH269@news.salford.ac.uk
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