Motor mount - too slippery to securely tighten on the Protos 500

[HarryR]

So, I had a lucky crash yesterday.
Flying a Protos 500 that suddenly, at about 60 ft or so did a 180 without my rudder input. Like, the tail flicked around in a sub second. So a brought the heli down to about 10 ft above LONG grass and then, it fell out of the sky, I was able to hit the TH and it "landed" feet down in the grass. Turns out that the motor mount worked itself lose and clearly, the belt skipped a beat ( tail flicked around ) and finally came off (crash). I replaced the main blades and test flew the heli. It is as good as new.
So I am wondering why it would be difficult to produce a simple "tensioner" with a simple screw that allows to you increase the tension ( on both sides of the frame. Just like the old bicycle / motor bike chain tensioner,

[crickr1]

Plastic frame or CF ?

Never had the problem on my CF frame but on the plastic it can get a little bugged up over time. Here is link for motor mount upgrade for the plastic frame

http://www.msh-direct.com/products/a...-500-only.html

[HarryR]

I have the plastic frame and yes I have those little gizmo's but they really do not work too well either.. they are just too slippery. So I am thinking that these inserts should be "rough" and " grabby" so the screw has a better bite. In fact I am wondering if it would be better if they would be CA'ed to the frame to provide additional strength too. But, there is another problem. The motor mount aluminum is way too soft and the screw will easily strip the thread. I had to replace two motor mounts already. I am telling you, the torque of that motor really pulls that motor mount / screw set... relentlessly!

[alexf1852]

Get yourself some external tooth lock washers from McMaster-Carr. You won't have to tighten real hard. The teeth will dig in and hold the motor in place.

[HarryR]

Originally Posted by alexf1852

Get yourself some external tooth lock washers from McMaster-Carr. You won't have to tighten real hard. The teeth will dig in and hold the motor in place.

.
I will try that ! Thanks!