TT 50 Problem

[scorchio]

I have just had a massive glitch that put my raptor 50 in the hard stuff from all of 6 inches.
The bad news is it flipped over and trashed the usual parts.
When it went over the engine screamed and I could not shut it off. Throttle hold, stick back and trim right down had no effect.
The side I could see did not have the fuel pipe to the carb visible so I just had to stand and wait.
The engine finally stopped and I inspected the damage, blades, main shaft, blade holder, feathering spindle. The Cluch bell had distorted with the heat from the cluch and was welded to the clutch.
I picked it up and took it home.
On inspection as I stripped it down to remove the welded cluch I noticed the engine had a rattling sound. After I had took the clutch off I removed the back plate.
The con rod had snapped, the engine was full of oil so I presume the heat generated while I waited for it to stop must have jammed the piston.
The piston ring is scored but the liner is ok.
The engine was running 10% prosynth and very rich, it's only had about 1 gallon from new, march this year.
I have tried to order replacement parts from the UK distributor amerang but there out of stock and do not know when they will be back in stock.
Does anyone know where I can pick up the bits I need Piston Ring, Conrod and gasket set or should I just get a new engine?

[Raptorite]

Hi scorchio,

Im sorry to hear about your mishap, its not a pleasant experience, I had a pretty similar one about this time last year with my at the time raptor 60, which after the crash and blown engine was upgraded to an OS70.

As for engine parts, I think in the long run you may well be better off just buying a new engine and be done with it. You may actually find that if you did find somewhere that had the parts in stock the cost may well be fairly close to that of a new engine anyway.

What sort of receiver are you using, PPM or PCM?

If you are using a PCM receiver you could do with setting up a fail safe to drop the engine back to idle if there is a radio glitch so you dont risk that kind of damage being caused again.

Hope this helps.

Cheers,

Pete.

[scorchio]

Hi Raptorite,

I cannot get the parts in the UK, the main importer has never had them in stock. So much for selling the TT engines with no spares.
I'm going to get an OS 50 and change the fuel.
I've got a JR 9 SPCM and the fail safe was set up. The trottle hold and trim down to 0 had no effect. The only thing I did not try was to switch off the radio.
When I first got the kit the throttle stuck once and I had to pull the fuel line off. This time the fuel line was under the heli and I did not risk trying to turn it over with the engine running at full belt.

I have no idea as to why the engine would not shut off unless the throttle had stuck again.

In a way I'm glad its hit the deck I have always been a little scared of crashing it and I think its held me back but now I've had the mishap the first one is out of the way.

New parts from helibits due to arrive today and I'll rebuild it tonight. My mate has lent me a webra 52 until I can source the OS at the right price.

Have you any experiance of ordering from the USA? The engines are almost 1/2 price.

[antsis]

Scorchio

Hard luck. Have you tried Just Engines? They don't deal with TT, but may be able to advise. In the end it might be a good idea to get a new engine.

Could be the throttle servo jammed. Did you check to see if the xtal hadn't fallen out. As Raptorite said, it's a good idea to set up the fail safe provided you are using a PCM Rx. I've set the controls to neutral and the throttle to idle on mine.

Ant

[scorchio]

Hi Ant,

I tried just engines and no luck. I've phoned almost every listed TT dealer no luck.
I'm going to get an OS 50.

As I said in my previous post the fail safe was set the only other explaination is the throttle stuck or the servo failed.

I'll change the servo to be safe.

Rick

[Raptorite]

Hi Rick,

I have only ever once ordered anything heli related from the states, it was a pretty good transaction though, delivered within a week or so I think from memory.

It sounds like the throttle must have stuck again then, especially as the trim was at the stop position the engine should have just cut.

I agree with you about crashing etc. I too was worried about crashing until I had my first one, then I wasnt quite so worried about it which really helped my confidence and ultimately my flying.

Its a good choice going for the OS, they are in my opinion the most reliable motor around, ok, they have quirks but every motor has them. With an OS its more or less fit and forget though.

Good luck with the rebuild and getting the OS in there.

Oh one quick point, dont forget to put plenty of locktite on the fan and/or crank nut when you install the OS50, they have a nasty habit of unwinding the fan off the crank when theyre new 8O

Cheers,

Pete.

[scorchio]

Hi Pete,

Rebuild complete.
Rain yesterday and today its blowing a gale. Typical.

Rick

[G-DAVE]

There is a constant theme emerging " GET AN OS " 100% Reliable.
Dave D

[Raptorite]

Hi Rick,

Isnt that always the way, when ever helis are done and ready to be tested, the weather is bad for days

Hope you get it in the air soon

Cheers,

Pete.

[scorchio]

Hi Pete,

Managed to get a couple of hovers in on Sunday. Still a bit windy, engine running very rich and I'm slowly leaning it out.

Not got it on the govenor and it's a bit tricky to setup with the gusty wind.

I noted your point about the fan and thought I'd put enough loctite on but the fan came loose and jammed the clutch on the the second start. A quick engine out and loctite had it back up and running.

I had a set of MS Composite carbon blades spare which I'm using, previously I had NHP Razors.
These blades are very keen and make the heli very responsive to wind change. It can drop a couple of feet before you know it.

I'm not sure if I should change back to the NHP's or stick with the MS blades.

Regards,

Rick

[Raptorite]

Hi Rick,

Im glad to hear things are going well with that new engine of yours, just be mindful of the fan when you start it while its as rich as it is. If it is sluggish to turn over when you try and start it, tip it over to the left (exhaust side) a little, this will allow the excess fuel to escape through the exhaust port, it will turn over better and be easier to start. Once youve run it in a bit and have leaned it out this problem will go away.

If you are not sure about the MS blades from a stability point of view, next time you get some, try some SAB's, they are a great blade and at about 10g heavier than the MS or the razors, means they are more stable in the hover and less suseptable to wind.

Cheers,

Pete.