mSR Swash movement at very low revs causing a wobble at flying speeds

[miniadventure]

Hi,

I have been trying to find out the problem with my mSR

At very low revolutions the swash moves visibly like there is a bump in the main shaft, at higher flying speed it causes the helicopter to wobble in flight.

The main shaft is carbon fibre so I thought that it could not bend in theory (only snap). I have had the helicopter apart and checked everything and seems ok. I have replaced the swash which did not change anything.

Is there any suggestions on what could be wrong, can the main shaft be bent or main gear warped maybe?

I welcome any thoughts

[John San]

What can happen to the main shaft is, it splits along its length.
It is often impossible to see until it is completly removed.
Then when twisting it by hand,it becomes visible.

'Easy' to replace.
A lot of people make there own from a length of 3mm hollow or solid carbon fibre rod.
IIRC, a 1m length costs less than half the HH price of a new shaft. You get about 6 shafts out of that.
But you will have to drill two small holes through the rod, if you make your own, and file a flat on the one end. Use the original as a pattern.

When I did this, I also found the original shaft was not round when measured at points along its length.


Current price for a HH shaft is around £8.50 plus p+p.

[miniadventure]

I did have the main shaft out to have a look to make sure that it was 'true' and it looked straight to me after rolling it on a flat surface. I didnt check for splits though as I didnt twist it whileit was off.

I will have a look at buying a piece of rod as I dont mind drilling / filing a new rod

thanks for your input