Mikado Logo 600SE washers above main gear

How many washers actually go above the main gear on the main rotor head?
Page 9 shows two 10x16x0,5 while exploded view on page 11 shows three with a combination of 2010(10x16x0,5) and 2009(10x16x0,2). Attaching pics of both page 9 and 11.

The first time I built the heli, the belt had fraying after 30 or 40 odd flights, had to change the belt then. After changing the belt, one of the pulleys just gave away, the belt seems to have eaten right through a pulley and the belt was rubbing against a non rotating pulley for couple of flights - (I have details and pics on another topic specific to this two days ago).

So just wondering if I have my main rotor shaft or tail belt tension configured incorrectly.

Thanks.



Edited 1 time(s). Last edit at 12/06/2020 08:13AM by glennj.

Hi,

the washers are basically thrust washers, and they can help with the alignment of the main gear.
But on the other hand, you want like 5/10 of axial play, of the main gear, which also helps with the alignment of the main gear.

Same goes for the washer between tail belt pulley and main shaft bearing, it's mainly a thrust washer, and it can help with the alignment of the pulley to the belt going aft.

You have force fit between the pin inside the tail pulley and the clamp ring above the upper main shaft bearing, so washers below as well as the main gear etc. below have no effect on the tail belt (tension as well as alignment).

Kind regards

Eddi

Born to fly ...
forced to work.

Thanks Eddi. Is it safe to mess with removing/adding any of these washers to get better horizontal alignment between the tail gear and the guide rollers ? (Meaning if I happen to notice the main shaft is either higher / lower than the rollers when seen from behind the frame)



Edited 1 time(s). Last edit at 12/07/2020 09:46AM by glennj.

Hi Glenn,

I would find it best if the shoulders of the pulley and the rollers align.

On the other hand, any belt will always run left or right, to one shoulder, and even more so if it's rotated 90°.

So moving the pulley up/down in relation to the rollers will always affect both sides, and probably conversely.

To be honest, I never put that much thought or effort in it, just mounted it bearing—washer-pulley with pin—washer—main gear with hub—washer—bearing (or bearing inside shaft support), checked visually if it aligned properly (good enough), job done.

So bottom line, is it safe to mess with it? With in reason, yes. Does it improve things? Maybe marginally. Does it help with the issue at hand? I would only see a relation if there was a huge offset, but there's not enough room for offset anyway (0.2 mm here or there won't win or loose a war, in this case, where the flat surface of the roller is worn, not the shoulders).

Kind regards

Eddi

Born to fly ...
forced to work.

ok thanks Eddi