redvtr1000
11-14-2007, 01:28 PM
I recently rebuilt my mt after a crash destroyed the blades, landing gear, stripped the main gear, bent flybar, bent main shaft, bent spindle.
When I went to fly it after repair, everything tracked great on the ground right on up to 1/2 stick. When the heli got light and started to climb out it shook pretty violent, got worse as power was decreased. Add power back in and it smoothed out. Reduced power to land it got worse.
Here is what I found/did last night. Replaced spindle again and lubed everything in there well. I have a new set of dampers but the old ones looked fine. I noticed that if I hold the rotor head with my hand and then reach down with the other hand and hold the main/tail drive gears and try turning the two against each other that I could turn the mainshaft in the bearing about 10-15 degrees.
I disassembled it to see where this turning was coming from. What I found is that the hole in the collar type part (slides through the main gear from the bottom and then into the tail drive gear, the bolt then passes through the nylon gear, this sleeve/collar and out the other side) seems to be slightly larger than the bolt. After installing everything and tightening it all down, I can hold the gear assembly in my hand and the main shaft in the other and turn the shaft back and forth a small amount either way before the bolt stops this from happening.
Is this normal? Do all of em do this? I don't remember it doing this before, you can actually watch the swash with it installed and see it twist it all a bit up there. A bigger screw would solve the problem but would mean drilling out the gear to fit it.
The hole in the gear is smaller than the hole in the shaft/sleeve so you can't put a larger bolt in unless you drilled the gear out a bit.
Someone give me some feedback...
When I went to fly it after repair, everything tracked great on the ground right on up to 1/2 stick. When the heli got light and started to climb out it shook pretty violent, got worse as power was decreased. Add power back in and it smoothed out. Reduced power to land it got worse.
Here is what I found/did last night. Replaced spindle again and lubed everything in there well. I have a new set of dampers but the old ones looked fine. I noticed that if I hold the rotor head with my hand and then reach down with the other hand and hold the main/tail drive gears and try turning the two against each other that I could turn the mainshaft in the bearing about 10-15 degrees.
I disassembled it to see where this turning was coming from. What I found is that the hole in the collar type part (slides through the main gear from the bottom and then into the tail drive gear, the bolt then passes through the nylon gear, this sleeve/collar and out the other side) seems to be slightly larger than the bolt. After installing everything and tightening it all down, I can hold the gear assembly in my hand and the main shaft in the other and turn the shaft back and forth a small amount either way before the bolt stops this from happening.
Is this normal? Do all of em do this? I don't remember it doing this before, you can actually watch the swash with it installed and see it twist it all a bit up there. A bigger screw would solve the problem but would mean drilling out the gear to fit it.
The hole in the gear is smaller than the hole in the shaft/sleeve so you can't put a larger bolt in unless you drilled the gear out a bit.
Someone give me some feedback...