Tricopter (Ycopter) Arm Length... the consequence.

Hi.

Here's a small info about my experiments with the rcxplorer.se tricopter.

I had it build as to the plans, but during a rebuild after e huge crash, i had to replace the arms, here i desided to do some testing, i streched the arms a bit, in my mind, this would create even more stability. I mesured the lenght of my wires, and added an extra 5 cm, (app. 1,5 inch) to the arms. No big deal.

But, to dial the settings in. Ohhh!!!!

 It had so much ocilation, wobble and unstability, i could not understand what there was wrong. I then got it dialed in at the best i could, and in a tail in hover, i studied the yaw and rear arm...

Surprice, BIG TIME.

A breif rudder input made the tail/yaw/arm go crazy. Wobble and shaking out of control, but yet the tri was maintaining it's hover??? Uhhh.

Some more investigation, and i realize that the flexing of the used pinewood is getting bigger and bigger as you strech out the arm.

Longer arm = more flexing

Shorter arm = less flexing

So the 48 cm (18,9 inch) is about the max lenght of pinewood arms.

You could though experiment with some reinforcement with carbon etc.

But then the entire plan of using wood goes down the drain.  

But her's the video.

I hope this answered some questions, and spared some experimental time and hair-pulling.

Rene'