Crashed my cub into a wall!

[foo]

and it survived! more or less...

Wings had shifted and I had to bend the tail fin back into position. The cowl is cracked and the spinner looks like it might be making contact with the cowl.

Cub flew fine after that, but the motor seems down on power. I'm not sure if the prop / spinner is touching the cowl now, I hope this is the problem and that I didn't damage the motor / gearbox / propshaft.

I'll take off the cowl tonight and inspect damage. What should I check and how do I go about finding out what's damaged? Has anyone had a head on collision before and what broke?

[ginginho]

While you have the cowl off, take the motor and mount off too, check the firewall for cracks or whether it's coming away from the foam. You could also take the motor out of the mount and check that the prop shaft spins without binding.

[foo]

Thanks for the reply! Can I test the motor by plugging into the Lipo without a prop? Or should I use a lower voltage battery?

Also, does the cowl serve any purpose other than looks? Can the cub fly without it? Might need to slice it up a bit to prevent contact with the prop.

[ginginho]

Jan 21, 2010 17:07:01 GMT 1 foo said:

Thanks for the reply! Can I test the motor by plugging into the Lipo without a prop? Or should I use a lower voltage battery?

Also, does the cowl serve any purpose other than looks? Can the cub fly without it? Might need to slice it up a bit to prevent contact with the prop.

I assume you still mean via the ESC and radio rather than directly to a battery...I'd guess so, but don't do it for too long as it'll be spinning quicker as there is no drag which the prop normally exerts. Brushless motors can suffer by doing this, not sure the same applies with a brushed one. A few seconds just to check it shouldn't be a problem.

The cowl is mainly cosmetic, but it does keep grass, mud etc. out of the workings. If you prop is striking it (after you've re-fitted it) then check your prop isn't bent. If you have another, stick it on and see if it still does it.

Checking is really a case of looking closely, pulling & pushing bits to see if they move when they shouldn't.

[foo]

Thanks again.

Pulled apart everything last night to inspect damage. Replaced the prop, cut the cowl to remove protruding bits, inspected the engine gearbox and prop shaft.

Everything seems fine. There is some forward / backward play on the prop shaft / gearbox, but I assume thats normal? Prop shaft seems straight on 50% power with prop on, but quite a bit of vibration on full power, again I assume this is normal. Plane doesn't seem underpowered on ground test. Firewall has small crack on a thin part thats behind where the engine and gearbox meets, but this doesn't look like it has any structural importance, nor is it protruding forward.

I guess I'll take her for a test flight as soon as there is a gap in the wind on a full Lipo and see how she performs.

[foo]

Took her out a few times this weekend, but she's not 100%. I've ordered a new gearbox with propshaft which I'll pick up on Wednesday.