It does to meDoes anyone think that 2 externally mounted ducts on a delta wing mounted just above the wing, at the rear and each side of the above blended fuselage seem like a good idea?
Anything's possible, but probably not.At high alpha landing would the ducts starve?
Anything's possible, but probably not.Or would the ducts draw more air over the wing and lower the stall speed?
Anything's possible, but probably not.Would the high alpha of landing create a wing tip stall that could saved by 'steering' with the ducts?
(Similar a dune buggies rear brakes when doing a wheelie.)
Probably not. I'm considering a similar package but it's one among many. First order of business would be to get the engine/motor/fan/duct worked out to your satisfaction, and size the delta accordingly. I've noticed a lack of enthusiasm for ducted fans in general because they're a lot of work to get set up, don't seem to work any better (or as good as) an unducted propeller, and you can imagine how much drag they'd have if the engine/motor quit.I have a design relying on this layout, if it's a turd please tell me.
There are two or three aero things going on, but first a correction: they are not more efficient unless you have a stringent diameter constraint; if you do not, an open rotor and more diameter is better. (Before you ask, yes, there is a strict diameter constraint on turbofans). I worked on prop aero and did some time writing performance decks at P&WA, so I'm not completely ignorant of this.Well, since some of you provided such thoughtful feedback on the question of fuel injection, I may as well put this one to you as well:
Why do ducted fan configurations seem to be entirely absent from LSA's and homebuilt's? Without having actually tried constructing such a propulsion system, I wouldn't imagine that cowling the fan with reasonable precision would be exceedingly difficult. Also, the challenges of weight and reliability of the cowling and drive mechanisms should be feasible too, given the indirect-drive configurations of many motorgliders.
The disadvantages that come to mind are potential fan balancing complications, and a drive mechanism that can handle the higher rpm's of ducted fans.
The benefits, aside from efficiency, would be smaller diameters and greater safety (given enclosure).
Just curious, really.