Raptor 90 first spool up

[dave j]

I spooled the rappy 90 up for the first time this afternoon the engine is an Os91sz-pumped it sounded awsome for about 2mins then it started making the most horrible noise like it was falling apart from the inside so i shut it down and as it came to a stop it locked up solid, i have stripped the engine out to find the only thing wrong was the nut that holds the fan inplace had worked its self loose which i cant understand as it has a spring washer fitted also 2 screws that tighten either side of the fan, can anyone tell me how to stop this happening again thanks in advance

[sacko]

A crank locking tool, a decent socket and some red loctite

[Gixxer]

As above ^^^ Loctite on all threads and use a crankshaft locking tool when you're tightening the nut on the fan.

[dave j]

hi sacko thanks for the reply the only thing on your list i didnt use was the red loctite so before i put it back together i will use some on it

[jwatts007]

I have never seen a sping washer used just a nut, is it the plastic fan you are using...

[dave j]

it is the plastic fan and the spring washer was in the box that the engine came in as it was brand new

[jwatts007]

Make sure too use the washer that came with the engine, and put it on 1st then a small amout of locktite and screw the fan down, then the nut no washer with a bit of locktite, also locktite the 2 screws in the side of the fan, all should be good then.....

[Dan22]

I spooled the rappy 90 up for the first time this afternoon the engine is an Os91sz-pumped it sounded awsome for about 2mins then it started making the most horrible noise like it was falling apart from the inside so i shut it down and as it came to a stop it locked up solid, i have stripped the engine out to find the only thing wrong was the nut that holds the fan inplace had worked its self loose which i cant understand as it has a spring washer fitted also 2 screws that tighten either side of the fan, can anyone tell me how to stop this happening again thanks in advance

Hi Dave,
I had exactly the same thing happen to me on first starting my Raptor 50 titan, the fan had also worked loose, but i had to strip the engine down, flush it out & re build it because the harder i was pushing down on the starter, the more the conrod tried to jump out of it's groove on the engine casing resulting in alley filings in the engine, but the plus side is i now know how to strip an engine.
I have since changed the engine for a Redline and locktited the fan on, then started it up again today, the engine started the first time, only problem was it was a 'hot start'!!
My first one ever but boy does it make you move quick, at least i had taken off the main & tail blades, although it managed to throw the starter off and wedge between some push rods!
As the servo was reversed, i just quickly pushed the stick to full throttle position, killing the engine, not much harm done although i was shaking for 5mins after!!

[dave j]

hi Dan i stripped the engine and gave it a good once over all looked ok, so i have put it all back together loctited everything took the rappy into the garden it started first time and runs sweet i just need to do some slight adjustments once its run in

[SansHeli]

Red loctite? Not blue? I thought the red stuff made it almost impossible to get the nut off again.

[RotorBlade]

I agree - red loctite surprised me too. I have only ever used blue when fitting the fan nut and never had one shift.
Having said that, I think red can be shifted with large amounts of heat???

[GIR8]

I have had this happen a couple of times in my early days of building. I then started using blue loctite as in the same stuff you use for everything else as someday you will need to take the hub off again and I wrap a cloth round the hub and hold very tight while cranking the nut on with a suitable socket.

You do not want to use a piston locking tool ever these things will at a minimum mark top of the piston and at worst punch a hole right through it. What you do want is a lever attached to the hub it self with a hole in the middle so you can still get a socket in. It would be fairly easy to make one you could use alloy plate heavy plastic or even wood if thats all you have.

[RotorBlade]

The piston locking tool is actually a nylon, crankshaft locking tool. It goes in where the bottom plate comes off and locks the con-rod to stop it turning. There is no way to lock the piston, which I agree would be a silly idea; there is no real alternative to locking the con-rod. A toothbrush down the carb port is equally daft as it will likely damage the port or just not work!

[dave j]

I used the crank locking tool and blue loctite i have had the engine running a few more times but noticed a lot of fuel coming out of the exhaust and was wondering if i remove the pump will this stop the excesive fuel wasteage

[GIR8]

This is what I'm talking about Prop Nut Tool

I wouldn't use a conrod locking tool either as you could do big end damage or bend the conrod. IMO anyway.