We have changed the Fusion 50 / Velocity 50 TT – the inside diameter has been decreased from 7.0mm to 6.6mm.

This change was made to increase TT regidity and minimise flex. The new TT part number is R50N315B-2.

Please note that when you use the new TT’s, you will require new TT end splines (your old ones will not fit). The new splines have part number R90N872B-SS.

It has come to our attention that there are a small number of front boom mounts which do not hold the front TT bevel gear bearings as securely as we would like.

Please take the time to check your front boom mount today.

Check Procedure:

1. Remove the front boom mount from the helicopter, and then the boom from the front boom mount.
2. Disassemble the front boom mount, and remove the counter gear.
3. With only the front TT bevel gear and associated bearings installed in the front boom mount, install and securely tighten the 4 M3x8 SHCS.

4. Test the TT bevel gear for play – left right, up down . Do not be concerned if the bevel gear moves longitudinally in and out of the boom mount along the axis of the boom.

5. If you notice any play or movement, please follow the following correction procedure.

Correction Procedure:

1. Disassemble the front boom mount again.
2. Place some 240 grit sand paper on a flat surface and rub the mating surfaces of both front boom mount halves on the sandpaper to remove any mold flashings, etc.

3. Test fit the front TT bevel gear and associated bearings in the front boom mount then install and securely tighten the 4 M3x8 SHCS.
4. Again test the TT bevel gear for play – left right, up down.
5. Continuing sanding the mating surfaces of the front boom mount until all play or movement is eliminated.
6. Re-assemble the front boom mount in the helicopter, remembering to re-fit the front counter gear.