Houston...I have a problem

[CatchmyCorsair]

Last time I flew my Stratus the engine got sluggish so I landed, tried starting again but the fan just spun. Figured the nut came loose. Man I only wish that was the case...

There were brass shavings everywhere around the fan and caked against the front engine bearing. Collets destroyed.

Anyone have a clue what the hell happened??!

The left collet was the lower, right was the upper. I'm gonna S#!+ a brick if my fan is ruined. (there are black marks, no way of telling if it ruined the tolerances until i try redialing)

[Mercuriell]

That's a bugger - looks like the colletts spinning inside the fan hub - it's pretty precarious getting that interference fit right while dialling in - did you polish up the engine shaft to produce sliding fit on the lower collett and ream out the upper to be a smooth fit also ? Might be time to upgrade to a Mary land fan

[Laurens]

I would say those collets are toast, lets just hope your fan is still ok. If not I would recommend a Maryland fan too.

[MrMel]

same thing happened to me, I went with a maryland fan, no looking back.
Not only will it sit there perfectly, but its also perfectly balanced, got alot less vibrations (even though I dialed the old fan)

[CatchmyCorsair]

Originally Posted by Mercuriell

That's a bugger - looks like the colletts spinning inside the fan hub - it's pretty precarious getting that interference fit right while dialling in - did you polish up the engine shaft to produce sliding fit on the lower collett and ream out the upper to be a smooth fit also ? Might be time to upgrade to a Mary land fan

I never polished the shaft, but I did take very fine grit sandpaper to the lower collet until it would press on. (that was a CHORE, so this really pisses me off!!) I did the same to the upper collet which was much looser/easier to slip on.

So where do I buy the Maryland fan? And why is it better? I see it uses the woodruff key, that makes so much more sense than the MA fan!

Anyone close to MA know when the new threaded fan will be for sale? I'd rather wait for that if it would be out near next Spring.

[MrMel]

http://www.runryder.com/helicopter/g...ryland_Machine

Its precision balanced + dont use collets.
Its so good precision that you need to put into the owen to heat it to get it on, then it fits perfectly.

[Laurens]

http://www.runryder.com/helicopter/g...ryland_Machine

Thats where you buy one. The main advantage is that its heated on onto the crankshaft. This saves you a lot of dial indicating.

[CatchmyCorsair]

Cool, that sounds great. Now since the brass collets spun on the crank, it left some residue(?), do you think I should polish the crank?

[MrMel]

I would have done it, yep, just cover the bearing/top of motor so you dont get small stuff in there.

[CatchmyCorsair]

Initially I balked at the price of that fan, but now I know the price is worth not messing with those dreaded collets!!!! Thanks for the help guys.

[Laurens]

I damaged my stock fan because I used the wrong fan puller, thats when I bought the Maryland.