moyesboy
05-25-2007, 07:11 AM
My tidy raptor 50 v2 which I bought used (but have had apart and reassembled) has a case of the wah wahs. A beating resonance that starts above 1400 rpm and is there in the hover. It gets faster with increasing head speed. It is more pronounced on descent (I have no governor as yet). It is least in a fully loaded climb but its still there.
I read all through raptortechnique.com and tried most solutions suggested there.
Motor is OS50 sx-h (not hyper) in great nick, smooth brearings.
Blades are bbt evolution 600mm. Fuel is CY wildcat 20%. System has had under 3 gallons through it including one from the previous owner who I have no reason to disbeleive. He said the heli ran smooth and it does at 1400 rpm stooge about speed.
This may have started after the first time I removed the motor to retighten the fan, but before that I was only running 1400 rpm headspeed - now I increased to 1700-1800 as I start aerobatics (This is my first notro but I already throw my trex450 about a fair bit).
A recent rebuild with new upper main shaft bearing, new main shaft, blades and several head components made no difference to the wah wah.
I have had a 0.2mm shim above the main gear, and removed it as it made no difference.
Nothing seems sloppy, everythng spins free.
I replaced the tail belt (as I though the beat might be once per tail belt rev)and tried different tensions to no avail.
You can see the wah wah frequency on the tail hold maybe, and on the exhaust smoke. gyro is CSM 560 (big old grey one) with futaba 9254 tail mounted and tail hold is very good otherwise.
I have varied the main and idle screws to no avail - once the motor is into 2 stoking with no missing the wah wahs build up.
The next thing I will try is the quickUK "3rd bearing on the clutch" upgrade. I ordered the parts and some new clutch bell bearings. I will also completely part the main frames and check the bearings are securely gripped and if necessary file down the frames to be sure they are clamped tight (as per raptortechnique build thread).
I found little mention of wah wahs here, and one post that said they were cured in the v2 (not in my case!) - has my v2 got a rare condition?
I read all through raptortechnique.com and tried most solutions suggested there.
Motor is OS50 sx-h (not hyper) in great nick, smooth brearings.
Blades are bbt evolution 600mm. Fuel is CY wildcat 20%. System has had under 3 gallons through it including one from the previous owner who I have no reason to disbeleive. He said the heli ran smooth and it does at 1400 rpm stooge about speed.
This may have started after the first time I removed the motor to retighten the fan, but before that I was only running 1400 rpm headspeed - now I increased to 1700-1800 as I start aerobatics (This is my first notro but I already throw my trex450 about a fair bit).
A recent rebuild with new upper main shaft bearing, new main shaft, blades and several head components made no difference to the wah wah.
I have had a 0.2mm shim above the main gear, and removed it as it made no difference.
Nothing seems sloppy, everythng spins free.
I replaced the tail belt (as I though the beat might be once per tail belt rev)and tried different tensions to no avail.
You can see the wah wah frequency on the tail hold maybe, and on the exhaust smoke. gyro is CSM 560 (big old grey one) with futaba 9254 tail mounted and tail hold is very good otherwise.
I have varied the main and idle screws to no avail - once the motor is into 2 stoking with no missing the wah wahs build up.
The next thing I will try is the quickUK "3rd bearing on the clutch" upgrade. I ordered the parts and some new clutch bell bearings. I will also completely part the main frames and check the bearings are securely gripped and if necessary file down the frames to be sure they are clamped tight (as per raptortechnique build thread).
I found little mention of wah wahs here, and one post that said they were cured in the v2 (not in my case!) - has my v2 got a rare condition?