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Pumpkin drop event

Simple Cub Micro

#1
So ive built the full size simple cub and have fallen in love, its brilliant. and now i want one for my indoor flying meetings, does anyone have any tips for building half size flite test models, is it even possible to make them fly at that size.
long story short ive crashed all my warbirds and am looking for something cheap and fun to fly.
 

Hai-Lee

Old and Bold RC PILOT
#2
So ive built the full size simple cub and have fallen in love, its brilliant. and now i want one for my indoor flying meetings, does anyone have any tips for building half size flite test models, is it even possible to make them fly at that size.
long story short ive crashed all my warbirds and am looking for something cheap and fun to fly.
It will be possible but there are a few things to remember!
The air you will be flying in does not scale and so just a size reduction and a proportional weight reduction will NOT result in a similar performance as the original model.

You obviously will require a much smaller motor, battery and ESC with weight being your enemy.

As for materials you do not require the same strength in materials as the larger model did. The paper on the FB makes up to 60% of the total weight of the material and where possible on a smaller model the paper should be removed completely. The tail members with no paper can be slightly sanded especially on the LE to reduce drag and improve aerodynamic performance. The fuselage requires no paper at smaller sizes.

The real issue is making the wing sufficiently light and sufficiently strong. The wing profile could be simplified to that used in the Mini Scout or Mini Speedster, (a simple spanwise fold around 25% of the cord. IF you remove the paper from the wing you could insert a strip of CF in the spanwise fold to improve rigidity. If still too flexible you can sand and then wrap the LE in a strip of paper that is applied over some glue. The paper wrap could also be applied to the TE if again it is too flexible.

Make the wing slightly larger in cord and span to help compensate for the change in Reynolds number and you should have something that will fly slow enough for indoor operation.

Try to limit the number of servos to 2 so either AET or RET setup is recommended and of course use the lightest servos you can afford. I consider 3.7 gram servos as at the large end of the weight scale for servos to be used/considered.

2S battery power is about right and capacities around 300mAh would be the best compromise in weight Vs capacity.

I hope that helps!

Have fun!
 
#4
Thanks for the advice, I’ve got the electronics from an erc micro boomerang in the spares box that I was going to use so hopefully I can keep the build light enough for it to work