Overwing engines: why don't we see this more often?

Originally posted by ch1466
I have to assume that it is an aerodynamic feature (similar perhaps to the gull 'step' on the Spitfire), but it may also be related to getting a deeper wingroot for a unified wingbox mount with a composite fuselage, added fuel (quite a few bizjets are not in the 3K+ legs range and some of the Gulftreams etc. are up to 6 I guess) or added baggage stowage reasons.

I take it you two are referring to the wingbox mounting?


Uhm, well, the reason its like that is to stop the wingbox protruding into the cabin area. I know the Lear 45 required some fancy workings of the wingbox [adding weight] to get it done like this, but apparently its a "must have" for the egos of the people buying them. Much like you need tinted glass on your bentley so the peasants can't see in

Originally posted by ch1466
Other things to be asked:

Does the keel effect of the engine pylon help or hurt in terms of stability and empennage drag? Do you get any adverse fencing effect with roll at yaw or similar coupled maneuver modes beyond straight and level?

- Stability in yaw: I think its mostly located behind the cofg, so should help damp yaw motions out.

- Drag: I cannot see it being good tbh - the engine blockage is in a region of faster flow than below the wing, drag being proportional to V^2....

Although wing fences have been used before to reduce spanwise boundary layer flow, reducing lift dependant drag.

- Dunno.