Building on the previous wing, I added an 9″ center section to permit more equipment mounting area, and to widen the stance of the wing to see if more stability is created. CG for maiden is via the online cg calculator for wings.
I’ve powered this with a blue wonder 1750kv, swinging a fairly mild 7″ prop. It appears to have enough gumption to be able to fly, but I’m not expecting a speed demon. Should be fairly docile.
The wing is hot wire cut out of white styro, with a clarkX airfoil (scaled by 70% for end). Appears very light and cg when using a 3s-850 battery is difficult to set, thus I added the fuse/canopy to give me that few extra mm’s to meet the CG I think it should be at.
Based on the FT designed $tree foamboard wing, this is a close design but built from Gray Depron, cover in laminate for strength, with no spars. Running a 3200 kv emax.
Flys extremely well! One thing I am learning with these wings is that elevens need a slight positive up angle, not coplanar with the wing. However, that in turn drives the craft up when under full throttle. To get around that, a normal mix should be created that drives elevens down when over 50% throttle is reached.
Closely based on the StingRay as designed by dz1sfb, this simple wing is made from a mix of grey depron & MPF, covered with laminating material on the lower surface. (34″ wingspan)
The original has a lower fuse out of layers of foam, I just hot cut some 2″ foam as a solid block, eyeballing the motor angle.
Since I want to see if this design actually flys well, I used a very small 1700kv Blue Wonder stick type motor, with an 8×4 very cheap prop held on a prop saver.
CG is exceptionally odd and important for a wing so I read, so spent some time getting this right. (I Hope!) Ideally it should be powered by a 3s, but since I really want to keep this light to see if it can survive a maiden, I opted for a 2s1300.
There was too much wind to fly this morn, so all in, the complete build of this wing including waiting for the GG glue to dry is only about 4 hours total.
Well, WTF 3 was a complete disaster. It was a clark airfoil and it looks as if I set the wing incidence too high. This resulted in its complete destruction on maiden!
Introducing the WTF 4 – This one I’ve gone back to the sipkil airfoil, mid mounted, at 40″ span. Slight changes to the rudder and elevator to help overall balance.
This one had to be designed while it was being built, as a motor from the Durafly Tundra is powering this one. I chose this motor as its base design is to use a 12×6 prop. It is much heavier than other 28 series motors I have tried, but accounting for this during the build/design stage ensured CG @ 1/4 was easily achievable. As typical for this design, a 3s 2200 lipo powers the plane.
The wing is hotwired from expanded foam, body is built from the 6mm grey depron (much less ridged than the white depron!) and tail section from 9mm depron.