My engine

[Pulsey]

Ok, I have a Raptor 30, bought second-hand, so I didn't build it or choose the add-ons.The only manual I have is for the Raptor.

The engine has on it 'OS Max SX'. Can anyone tell me from the preceding info the exact model and where I can get a full manual for it? If not, what other info do I need?

Secondly (and related) I'm having some fuel problem. It quite often fails to fire at all when starting up. On Saturday, it fired from fresh and I played around for about 10 minutes, after which the engine just died and wouldn't restart. This obviously needs sorting but I'm struggling to isolate the problem.

I'm OK with electronics, but a novice mechanically, so here are some dumbklutz questions:

1. Does glo fuel need any electrical imput after it's started or is the glo plug all it needs - just the initial 'kick'?
2. Is it purely a suction effect that keeps the fuel flowing from the tank?
3. Why might it then just die on me? It was running fine, not roughly or particularly slowly. I had plenty of fuel. Batteries were charged. In the preceding couple of minutes there had been a couple of times when the revs had dipped on their own accord for about 10-20 seconds before recovering (a very noticeable dip, but only the 3rd time was enought to stall it. The other times it recovered). Could the fuel filter be blocked and if so, can it be cleaned and is it polarised?
4. Until I get hold of the manual, any tips for adjusting the fuel-flow valve (or whatever it's proper name is)?
5. Why is there a connection from the fuel tank to the muffler?
6. Why is there a smaller (I call it reserve a la motorbike) tank and why does it have a third bit of tubing going to a dead end? refuelling?

That'll do for now. Be gentle with me!
Thanks,

Andy

[Stuart]

Okay,

Here's a link to the site for OS - www.osengines.com

This is most probably the engine....http://www.osengines.com/engines/osmg1940.html no doubt be the manual for it..... http://manuals.hobbico.com/osm/32sx-h-manual.pdf

All your answers are in their...once you have a good read all your questions will be answered.

The fuel goes from the main tank to the header tank (aka your reserve idea) then into the engine carb, then a fuel line from the muffler to the fuel tank keeps some pressure in the tank when the engine is running to help push the fuel through to the engine.

No dumb questions here, we all had to start somewhere, just shout if you get stuck.

[Disc]

Find a local club if you can because if you start it wrong it could bite you!

[Disc]

Find a Club if you can

BMFA Club list is here:

http://www.bmfa.org/clubs/clist.php

double posts lol

[Philimon]

...
1. Does glo fuel need any electrical imput after it's started or is the glo plug all it needs - just the initial 'kick'?
2. Is it purely a suction effect that keeps the fuel flowing from the tank?
3. Why might it then just die on me? It was running fine, not roughly or particularly slowly. I had plenty of fuel. Batteries were charged. In the preceding couple of minutes there had been a couple of times when the revs had dipped on their own accord for about 10-20 seconds before recovering (a very noticeable dip, but only the 3rd time was enought to stall it. The other times it recovered). Could the fuel filter be blocked and if so, can it be cleaned and is it polarised?
4. Until I get hold of the manual, any tips for adjusting the fuel-flow valve (or whatever it's proper name is)?
5. Why is there a connection from the fuel tank to the muffler?
6. Why is there a smaller (I call it reserve a la motorbike) tank and why does it have a third bit of tubing going to a dead end? refuelling?
Andy

To Answer your questions
1. No. The glow plug takes care of all of that. The initial current passed to the glow plug is only used for starting. After that, the catalytic reaction with the platinum keeps the plug glowing without any further current. My advice: get a new glow plug if its an old or unknown heli. At around £6 they're cheap.

2. On your average setup, its a combination of several things, all relating to air pressure or a lack thereof. But no, typically there is no pump involved, although they are available and many pilots will use them.

3. Check the fuel filters are clear, that there is no dirt in any of the systems from tank through to carb and that there are no bubbles in the fuel line. Make sure the carb is properly seated onto the engine case. Check the o-rings for leakage.Personally, I would replace all fuel lines and o-rings just in case - even the lines in the tank. 1 metre of fuel tube costs less than £2.

4. OS Web site links provided previously are best place to start. There are two current OS engines for your heli - the 32 and the 37. Markings on the engine should give that away - have a good look and download the right manual.

5. The exhaust pressure is transferred to the tank thus pressurising it and providing a more constant flow of fuel to the tank. If this was not the case, as the tank got empty, the pressure would drop off markedly. Think of a leaking bucket...

6. The smaller tank is called a header tank and, to keep things simple, its used to help prevent air bubbles from getting into the fuel line while the heli is bouncing around. The third line is, most likely, used for refuelling.

Hope that helps. Good luck and do get BMFA & Local heli club involved.

Regards
Andrew

[moyesboy]

Both the header tank and the main tank have "clunk". There is a tube with a weight on the ned that pick up the fuel and it follows the fuel (and avoids the air).
The header tank is fed from the clunk in the main tank.
The engine is fed from the clunk in the header tank.
The header tank should remain full until the main tank is empty. That was the engine can never suck air.

You fill through the header so the header tank gets full, then the main tank fills.

Over time the tube on the clunk can perish and split. That might be your problem. Air then gets into the fuel line.