R22 freewheel wording
Thread Starter
Joined: Jul 2010
Posts: 255
Likes: 0
From: france
R22 freewheel wording
Hi folks i understand this topic has been beaten to death, however i just want to make sure one last time i have my wording right.
When the engine is running the sprags are locked into position, the torque is transferred from the outer race integral to the upper sheave to the inner race by the wedging action of the sprags and from the inner race integral to the clutch drive shaft, forward to the mrgb and rearward to the trgb.
If the engine quits, the torque from the clutch drive shaft will exceed the torque from the upper sheave driven by the engine, the sprags will roll, allowing the shaft to spin freely without any drag from the engine.
Is that correct?
Finally, how many bearings are there in the robinson? I counted three: one on the upper sheave, one on the mrgb and one on the trgb, am i missing any?
Many thanks
Baobab72
When the engine is running the sprags are locked into position, the torque is transferred from the outer race integral to the upper sheave to the inner race by the wedging action of the sprags and from the inner race integral to the clutch drive shaft, forward to the mrgb and rearward to the trgb.
If the engine quits, the torque from the clutch drive shaft will exceed the torque from the upper sheave driven by the engine, the sprags will roll, allowing the shaft to spin freely without any drag from the engine.
Is that correct?
Finally, how many bearings are there in the robinson? I counted three: one on the upper sheave, one on the mrgb and one on the trgb, am i missing any?
Many thanks
Baobab72
Joined: Sep 2007
Posts: 368
Likes: 21
From: I am not sure where we are, but at least it is getting dark
Your description of the freewheeling unit seems correct to me.
Number of bearings: What kinds of bearings? Ball and roller bearings only? Even so, there are a lot more than three. I think there are at least 5 in the MRGB alone. Then clutch actuator upper and lower bearing, tail rotor driveshaft damper, tail rotor gearbox, rotating swashplate, blade grips, tail rotor pitch control... etc. Plus the ones inside the engine.
Number of bearings: What kinds of bearings? Ball and roller bearings only? Even so, there are a lot more than three. I think there are at least 5 in the MRGB alone. Then clutch actuator upper and lower bearing, tail rotor driveshaft damper, tail rotor gearbox, rotating swashplate, blade grips, tail rotor pitch control... etc. Plus the ones inside the engine.
Joined: Sep 2007
Posts: 600
Likes: 0
From: USA
The functional description of the R22 overrun clutch is basically correct. I would just offer one minor technical correction that the sprag elements grip or slip based on friction due to a relative speed differential, rather than a torque differential, between the input and output race surfaces.
As for bearings, the R22 sprag clutch design uses two ball bearings.
As for bearings, the R22 sprag clutch design uses two ball bearings.
