|Jul 15, 2010, 05:25 AM|
Scratch builts, My 40" light weight wing.
This is my park flying wing design, they fly great. If you want a light slow fly performance wing with great handling and glide, this rocks.
Application is slow flying, park/street low level and downgraded to combat as they start to get old and trashed. This is the 6th incarnation, the last 4 have had the same wing profile with just some fuselage, covering and elevon changes. This one has laminate covering (so far so good, nice finish and stiff wing). I accidently put a little Ahedrial in the wing when applying the laminate which has made some performance issues in slow flight (nose dips when turning out of a left bank turn?) Otherwise this build is faster than my previous due to covering material and streamlined fuse. I changed the engine mount and cut the mount into the wing instead, this made for better thrust angle and now can accelerate and maintain level flight without radio input.
Performance is superb, great glide ratio, vertical performance, light weight for crashes, can slope it in light winds and fly in tight areas.
AUW 300gram, 610mah 3S, HXT 24Gram motor (1500 or 1700kva), gws 7x6 (nice and quite).
Air frame: styrofoam, 40" span, 10" root, 6" tip, sipkill airfoil, 30 degrees sweep, 2 degrees washout.
The fibreglass bumpers (from HobbyKing) protect the leading edge (I fly these wings low around trees and in my street around light poles, letter boxes, etc so the bumpers get used some times. They are removable, I adjust the battery position to adjust CG when removed.
I continue to build these, they are just so much fun, I'm happy with the current design, minus the ahedrial in this latest build.
Here is some video of it with keyring camera (cap mount and onboard)
|Jul 18, 2010, 04:03 AM|
Dimentions for build
If your AUW is going to be over 300 gram, then you may need to upgrade to a 1000mah 3S and HXT1700 or better motor to get vertical performance. This model is styrofoam which is a little lighter than EPP. Being so light and with the bumpers, the air frame still lasts through considerable punishment untill I downgraded them to a combat model.
AUW 300gram, Rhino 610mah 3S, HXT 24Gram motor (1500 or 1700kva), gws 7x6 (nice and quite), ESC SS 15 Amp, 3mm square section carbon rods, all from Hobby king. Motors: High KV with small prop are nice but, they are less efficient and provide less thrust and acceleration than a large prop for the same current. As this is a slow flyer, I would stick under the 1700kva motor range.
The 610mah is only 51gram, but needs good ventilation, especially on the 1700kva motor, it is 20C = 12Amp max constant current. I've found the lifespan of these batteries to be fairly short. I would now suggest 800-1000mah 3S for longer life and better power delivery, you may have to go a bigger motor (not higher KV though).
Air frame: styrofoam, 40" span, 10" root, 6" tip, sipkill airfoil, 30 degrees sweep, 2-3 degrees washout. The front bumper is a memory plastic foam packing material. I have a cardboard template I use for the cut outs for an acurate CG. You can get a fairly good idea from the photos how much to cut.
Make sure the wing is built without Ahedrial, slight dihedrial is OK.
Light weigh laminate works great as a covering and additional support. I have laminate info on my blog.
|Category||Thread||Thread Starter||Forum||Replies||Last Post|
|Discussion||2 photos of scratch-builts||Michael in Toronto||Foamies (Scratchbuilt)||3||Mar 16, 2009 02:39 AM|
|New Forum? - Scratch Builts||martin johnson||Electric Plane Talk||75||Nov 11, 2001 03:33 PM|