T-Rex 600 NSP clutch loose

[Stellaship]

I've missed two lots of flying now because I've failed to properly secure the fan and clutch assembly to the engine. Tightened the nut and fixings up nice and tight, all thread-locked, but on first attempt to start the assembly spins on the engine.

On the way home from the field it occurred to me that maybe I need to tighten the screws that clamp the assembly to the engine shaft before tightening up the nut, as I'm pretty sure last time I did the nut first. Anyway, any tips would be appreciated as I'm getting frustrated at not flying!

[sacko]

Get a crank locking tool, and some red loctite

[robgt]

Take the backplate off the engine and insert a crank locking tool.
Then use a good socket wrench and get the top nut nice and tight - use a bit of blue threadlock on the nut.
Finally, tighten the two bolts on the side of the fan hub equally to keep everything sitting sweet.

Cheers,
Rob

[tonystevens]

Tighten the prop nut before you tighten the clamp bolts otherwise your fan hub wont bottom out on the crankshaft.Get yourself a crankshaft locking tool if your struggling to tighten the propnut fully

[Aidi]

Best practice is to do the main nut first, then the two that clamp the fan to the crank shaft. You really have to give the nut (making sure you have the flat side of the nut it to the motor) a really good crank to get it nice and tight. A cloth around the fan assembly normally helps or you tend to rip your hands to bits!

Then, the two bolts on the side of the fan hub. Nice and tight on these too, but not too much as you are screwing into aluminium.

BTW, where in the Cotswolds are you flying?

Rgds
Aidi

[Aidi]

(not bad having 4 answers to a question in the space of 5 mins!)

[Stellaship]

Wow - thanks for the speedy responses all!

I used a crank locking tool and blue thread lock. Still, on the second spin of the starter it was loose.

At least it looks like I'm not missing anything so will just have to try again.

[Stellaship]

Thanks Aidi - I fly with Gloucester Model Flying Club.

[Aidi]

Thanks Aidi - I fly with Gloucester Model Flying Club.

Just asking as i frequent the area quite often. Must pay a visit one of these days as its not too far from where i go at the weekends.

Rgds
Aidi

[barney]

Just a late addition to your question if youve yet to dismantel.

Are you sure Its not a duff one way brg in either the clutch or your start shaft as with the crank nut + pinch bolts they are generally very secure. If you have to strip it down also make sure the split in the hub does not line up with the crankshaft Keyway.

cheers Brain

[gorber]

Might be a silly question, but have you checked the grub screws on the starter cup at the top of the assembly?

Mine have come undone many times.

Easy to fix as well, no need to disassemble everything.

[Stellaship]

Aidi - I'm sure you'd be welcome at the field. I'm a relatively new member having joined back just before Christmas. They're a friendly bunch and there are quite a few helicopter pilots.

Barney - saw your post after I got it all apart, but it is what I thought rather than the one way bearing.

gorber - would have been nice if it was them! As above, it's the engine out, back of the engine off and fuel everywhere job instead!

Got it all apart now, but will leave cleaning it and re-assembling to another night.

Thanks for the super speedy tips all