I agree it would be better with a low AR planform....IE not a Glider type.Naturally the ability to control the thrust/drag couple is the distance the pitch control surfaces are from the aerodynamic centre. If you are talking about a medium aspect ratio plank, the application of throttle coulud cause a catastrophic stall if you were near the ground - its not a good design feature - stability in planks requires that the thrustline ahd drag as as coincident as they can be.
your idea would be acceptable fo very low aspect ratio planforms.
Many thanks CluttonfredI am happy to help but it's a pretty long article, somewhat technical and old-fashioned. Exactly what did you want me to translate?
I do like the adjustable engine height and longitudinal position of the mounting on that fuselage...The idea is possible provided that proper consideration is given to the thrust/drag couple, Gyro designers recognised this problem long ago, unfortunately too late for some lost pilots.
probably the best fuselage to copy for a high wing plank would be the HM14, it is super simple and the engine can be raised oe lowered to align with the drag vector.View attachment 101909View attachment 101910
Yes build the flea but only the 1936 version, DO NOT ATTEMPT TO BUILD THE INITIAL 1934 VERSION!!!I built an HM14, It was a long time ago but it only took 3 or 4 sheets of 1/8” ply and a few pine sticks for longerons, it certainly didn’t cost $4000. The bare fuse only took a week to build. I used spring steel legs for the UC but the original had wheel barrow wheels on a pipe axle tied to the lower longeron with bungees for suspension.
It is worth reading Le Sport de L’Air, it contains complete plans instructions and materials to build an HM14, the book is freely available on the net.
Not me, Too windy. The pilot was the great Eddie Clapham who has done the test flying on most of my aircraft. The LAA chief test pilot who is a professional TP also flew the aircraft. Both thought it flew well. Just a few more tweaks needed.Great shots, Mike. Is that you in the cockpit?
Why should there be? As I see it a plank is simply a tailless airplane that controls pitch by adjusting the airfoil pitching moment. A long chord allows you to do that with less elevator deflection so low AR is actualy an advantage in that one aspect. A long root chord also allows you to get more of the non lift producing stuff out of the wind which would seem to be a plus for reducing parasite drag but the induced drag of the short span pretty well negates that.Is there an AR limit where a plank is not a plank?
Sweep is great but if your tips stick out of a rectangle defined by the root chord and span you realy shouldn't call it a plank see attachment.In the earlier post I mentioned the use of a swept plank as well......
Yeah it'd have to be converted. That thick high camber airfoil would be a lousy choice for a flying wing. You CAN get a positive pitching moment by reflexing trailing edge control surfaces but that dumps a lot of lift and creates a lot of drag (L/D goes down the toilet) so basically the only part of the kit wing that's usable is the spar.The wing on the D8 kit would have to be converted, as I mentioned, to something that was appropriate...