Wednesday was a pretty good day. It marked the arrival of a mini-DVR camera I’ve wanted to buy for quite some time. It went on sale for Fathers day at nearly 1/2 price. I just could not pass up the deal!

The location of the aperture is not perfect, but I can work with it. In fact I have a new canopy on the way from Hong Kong, that will be cut so I can mount the camera forward of main rotor head, and a little lower to make sure it’s not at risk of a blade strike. In the mean time I have a mount position rear of the main rotor that works OK. I like to have a little bit of the helicopter in view to give some perspective.

Here is an in-door run-up test of the camera.

Having found a suitable location, and even though I’ve still not sorted out the mystery vibration in the main drive train, I wanted to take it out for a flight, and shoot some POV video off the helicopter.

Here is the POV video:

Unfortunately, this was the aftermath of the crash. Broken main blade grip. That really annoying part is that this one of those 2% of the parts that is NOT directly ALIGHN TRex 450 compatible.

I’m able to source ALIGN 450 parts at the LHS (local hobby shop), but these design of these are so different that I don’t think I can use them. The bearings are the same size but they mount in different locations, and I think it’s allowing the blade grips to shift a few thousandths of an inch off-center, making what I know to already to be a nasty run-out on the main shaft, even worse. I’m fairly certain that it’s not an issue with the shaft itself, since I have 4 of them now (1 original and 3 replacements) and they are all showing the same runout when mounted in the drive system (video below shows the problem I am having).

You may notice wobble in the in-flight POV video. That’s not the camera. That’s actually the helicopter when it gets into this harmonic resonance with the main shaft vibration. It can be pretty nasty, and it certaily didn’t help me when I lost control and crashed.

I’m doing some research, consulting with the great oracles, and just trying to sort out the possible cause of the strange shaft run-out. So far, I’ve come across the solution, or solved this problem myself. Here is a video of the some testing I’ve done to quantify the issue: