Ultralight Aircraft

Air-Tech Rotax Gear Box Clutch

No one will ever dispute the fact that a 2 cycle engine is not happy at very low RPM's with a large flywheel attached to its PTO end. The flywheel of course is the propeller.This dissatisfaction is usually responded to with severe shaking and rough running. This action can be easily proven by simply removing your propeller from your gearbox and then start your engine. You will notice that it hums like a sewing machine (kinda), well at least it's no longer trying to shake it's self off of the motor mount. The reason for this smoothness is due to the fact that the engine is not laboring to spin your propeller at idle RPM. Even with the propeller installed, the engine eventually will smooth out at around 2800 RPM.  All this banging at the lower RPM's is torture on the crankshaft and piston bearings.  Our two stroke Rotax aircraft engines are one of the very few systems that actually start up under a load.  The reason most 2 stroke applications use clutches in the first place is cause these engines develop minimal H.P. at the low RPM's.  This clutch is virtually maintence free. The only time any wear is taking place is during the transition from idle to run power.  Once the clutch is engaged the engine is fully connected to the gearbox.  You should set the idle to 2000 RPM.  The engagement RPM is at or near 2300.  Only available for the Rotax "C" gearbox.  

The design of the clutch was based on the crankshaft RPM being at least 6,450 RPM.  

We have made adaptors to allow this clutch to be used on other engine packages.  Call us for custom applications.

Install Instructions


Clutch, Assembled

Clutch, Assembled

# RK400C
Price: $550.00

Clutch, Retaining Plate

Clutch, Retaining Plate

# RK77
Price: $60.00

Clutch, Drive Body

Clutch, Drive Body

# RK44
Price: $248.00

Clutch, Drum

Clutch, Drum

# RK33
Price: $203.00

Clutch, Mechanism w/Springs

Clutch, Mechanism w/Springs

# RK66
Price: $140.00

Screw, Flat Head Clutch 3/4 Inch

Screw, Flat Head Clutch 3/4 Inch

# RK88
Price: $0.29

Bolt, M10X16 Clutch

Bolt, M10X16 Clutch

# RK22
Price: $0.80