My first scratchbuilt plane

Started by Swapnil, June 16, 2011, 12:51:27 PM

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Swapnil

#25
Added flat-bottom thermo aerofoil to the flat coro wing. Also, the wing now has a 3o dihedral.


Swapnil


naatumach

What is the current weight of the a/c?
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

Swapnil

It must be around 800 gm or less...

naatumach

you still need to lose weight i guess. Because i also tried to make a coro a/c one it had no extra parts to it, not even wheels still it didnt fly, but again the thrust to weight ratio was bad, i really suggest you find out the thrust to weight ratio. Because of the motor setup i have i know that the assembly alone doesnt have a 1:1 thrust to weight ratio. Thats why i used depron and "airfoil".
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

naatumach

Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

Swapnil

#31
Power to weight ratio = 243/1.76 = 138 Watts per pound.

Thanks for the link!

naatumach

According to one of the people i discussed this matter (long time back) 138W per pound is comfortable.
Also find out the wing loading using this http://adamone.rchomepage.com/design.htm
And compare with http://en.wikipedia.org/wiki/Wing_loading (you'll have to change the units)
What values come?
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

Swapnil

Attached pic of the wing loading (weight taken as 700g).

The cubic loading comes out to be 8.73 oz/cu.ft. And the range for  trainer/ sport type models given on the website is 7 to 9 oz/cu.ft.

Thanks for the links again!  :thumbsup:

Swapnil

here's the wing loading data...

Jatayu

Hi swapnil!

Great Build! isn't the airfoil too flat in the front??? I think it could be rounded a lil more??
Spektrum Dx6i | Blue Baby |  Fast Cat | TB-20 | Speedy | Lil' Ripper| Little Elley| PT-20 Ryan | Delsoro - SAE Heavy Lifter | Hiller 450v2|2x AXI 2217/2|2x Castle Creations- Thunderbird 54A| 2x Thunderpower RC Lipo 850mAh 65C| 10x Futaba s3114

SAE Aero Design West- 2011
1st Place Highest Payload Lifted
2nd Place Operational Availability

Swapnil

I know, but the the airfoil base is made of coro and can't be rounded. Also, it's a close-up shot, it looks O.K in real.

Jatayu

 :salute: :salute: all the best for the flight! 

Happy Landings!  :)
Spektrum Dx6i | Blue Baby |  Fast Cat | TB-20 | Speedy | Lil' Ripper| Little Elley| PT-20 Ryan | Delsoro - SAE Heavy Lifter | Hiller 450v2|2x AXI 2217/2|2x Castle Creations- Thunderbird 54A| 2x Thunderpower RC Lipo 850mAh 65C| 10x Futaba s3114

SAE Aero Design West- 2011
1st Place Highest Payload Lifted
2nd Place Operational Availability

Swapnil

Thanks!
It's rainy/ windy here all the time these days. Hope to maiden it soon.
And thanks for the advice, I'm not much into maths or deep-study of aircrafts.
Just wanna fly! :)

naatumach

hey swapnil. I just remembered a great idea, which i used to do. It really helps.
Remove the break-able parts of the a/c, replace with equivalent weights, now if u want to find something of the equivalent weight, use a 30cm ruler, place your known weight on one side and a dead weight on the other, and try to balance everything keeping 15cm as the pivot. u can use cells, tubes or anything as dead weights.
Now strap all the dead weight on the 1/3 line and launch it (gently). u can tape the elevators up a bit, and its your choice where u want to land it, ground, grass or any person's hands.
This will accomplish one very important thing if the battery fails, will the a/c land safely or will it fall like stone. You will also be able to see how the airfoil effects the flight.
Motto: build, fly, and modify.
Prefers working on designs than electronics.
No pre-made plans. Use blueprints, make calculations, build, fly, troubleshoot, fly again.

Swapnil

Really good idea, will certainly try it. Can't do it right now as I don't have enough space indoors and everything's wet outside.
Thanks and keep the tips coming!  :)