Hi All,

Here's my pusher trainer built along the lines of Tony 55x65's 'Tuffy'(rcgroups). The specs are:

Span - 48"
Chord - 8" (wing - 190g)
Length - 33" (fuse - 190g)
 
Motor - 2212/10, 1400 kv (65g)
ESC - 18 A (35g)
Battery - 11.1 volts, 1350 mAh, 3s Li-po (all three from Sai's RCforall) (110g)
Servo - 9gx2, Futaba S3114 (18g)
Rx - Futaba standard 4 ch (30g)
AUW - 650 g /23 oz
WL - 8.6oz/sft

The wing is made out of thermocol, reinforced with balsa LE,TE & spars with cardboard center sheeting and later covered with chiffon(dupatta) material using diluted fevicol, and blow-dried with a hairdryer.

The pod is made out of compressed t-col, salvaged from packing leftovers and the boom is a 1/2x1/2 in teak wood beading. The tail unit is made out 4 mm coro salvaged from my front gate.

The plane's not much of a looker but is very stable and glides well. As a beginner, some hard landings are natural - and this one has had its fair share.

Here are a few pics.

-B

 

My eyes still not able to believe how high it can go.. It is indeed a good flier I will probably make a similar to practice and save some props

This is the most efficient plane I have seen till now

more pics plz..

thanks, foamybuilder, findvikas......I am unable to post pics....what am I doing wrong?

hope this gets through....

guess it was the size of the pics....here are a couple more....

 ha....I cracked it.....its two at a time, considering the size

extreme improvisation  
the dupatta wings look great  

Very nicely built, i have seen this model fly last weekend, i was very impressed by the wing specially.

Thank you !

here are a couple of pics from the build phase....will post pics of the wings build when I am able to locate. BTW, a slab of stone, easily found at any construction site(or you can buy for a few rs) serves well as a weight when you want to provide uniform pressure when sticking thermocol

hi,

this one is totally scratch built and made from 2mm spad.

flys very stable and looks  beauty in the air.

regds
sandeep

nice

built 3 pushers in a workshop held in VIT college pune.

all three flew off the board successfully

looks sharp, Sandeep.....mine needs a lot of refinement

Nice trainer sir.. Could you explain the chiffon coating process in detail?

chiffon covering for thermocol wings

In order to strengthen the wing, you can try using chiffon. A 2.5m x 1m weighs about 60 grams and you will use only a fraction of that for a wing measuring 48 x 8 in.

I suggest you cover each side of the wing separately - I mean left and right and not top & bottom. Cut out an appropriate length and start with the TE at the bottom of any one side - you could stick about 1 in with regular fevicol. I use a brush used for applying hair dye to evenly apply fevicol - use sparingly, else it would increase the weight. Stick the chiffon and spread out whatever wrinkles you may get. Don't fret if it becomes messy as you can peel and re-do but be careful else the dried fevicol would make adhesion tricky. So, I start from the TE on the bottom of the wing, go over the top and end, overlapping the 1 in border you started with. You can trim the excess with scissors and further trim the strands with a razor blade.

Leave it in the sun for a few minutes , but not too long. Its best to do both sides first with min. drying. Once dry, apply a thin coat of diluted fevicol, just to have a smoother surface and then blow dry it, while running your hand over to remove excess fevicol.

You can be sure to get a super strong wing which is not as heavy. It is a bit high on effort but the results are encouraging.

Hope this helps.

Thank you so much for the explaination sir will try it..

Quote from: bmblb on November 30, 2010, 11:22:21 AM
chiffon covering for thermocol wings

What if we use araldite? that stuff is super strong!!

 araldite is an adhesive and may not be appropriate for this application. Besides, you'd need a lot to cover the entire surface of the wing, thus making it heavy - time to dry is another issue. And it may still not prevent the granules from eroding over time.

The strength of a finished wing made out of t-col, reinforced with balsa/spruce and then covered with any light fabric IMHO is a combination that I have found to work well. My first such wing was made over 13 years ago and its still intact.

13 years 
i'll have to trust this technique and your experience.

try it

.....if you have a hot wire foam cutter (make one - its simple) and can cut clean wings(just takes practice....t-col is cheap, even if you waste a few sheets)....and with some trial and error, you should be able to produce good quality wings at low cost.

Just to give you an idea, I made another wing with the same dimensions(48 x with 4mm coro(could not get 2 mm) and my wing came out at 280g - where as the t-col wing weighs 190g.

Another lesson - the trainer discussed here has done a few nasty cart wheels (landed on nose>wing tip>tail> other wingtip>stop) at good speed and strong wind - seeing from a distance I was almost certain that the wing would be damaged....but its in decent shape.

One small detail - you may like to use strips of bamboo for your wingtip at the edge of the washout.

i'll definitely try this. thanks for the explanation and tips.