Anyone know anything about 0.049 engines?

[fychan]

I'm coming into the finishing straight of making my first gas powered balsa aircraft, and I've run into a stumbling block.

I bought a brand new Cox 049 Killer Bee engine, and have been trying to run it in, while it's mounted to the firewall, but not yet attached to the plane. I've been following the instructions, but although I can now get it to start fairly regularly (that in itself took a LONG time), it won't keep running.

Or at least, it will as long as I hold the fuel tank (I'm using a refill bottle at the moment, the tank is embedded in the fusilage already) above the engine, and it uses the gravity to pull the full through. The moment I lower the bottle to the same height as the top of the piston the engine splutters and dies.

The same thing happens if I don't keep a constant pressure on the sides of the bottle. I originally put that down to the fact that the bottle is airtight, and after it ran, there would be a slight vacuum which would stop the fuel running easily... So I switched to an open cup... I can't get it to run at all from this open tank. It won't even start. I can't hold it above the engine now because the pipe into an open tank won't lift the fuel over the cup edge, and the engine doesn't appear to have the power to lift the fuel from below the engine.

I'm now SERIOUSLY worried that the engine won't run when I've mounted it onto the plane... Which I would NOT be happy about... strangley enough

Any advice would be VERY gratefully received.

[freefall]

try a 1oz tank clunk stopper located as even with the reed on the backplate as you can and as close to the firewall as you can we use a 2 line system as 1 line goes to the engine and the other line vents above the tank and uses air pressure created from the prop.

[freefall]

forgot to mention we use a 1oz round tank.freefall

[Hank]

Cox .049's run and run well. If you are having problems. Make sureyou are using "hot" fuel! That is fuel with at least 15% nitro content. Regular cox fuel out of the metal can is good if it is FRESH. If your fuel has been sitting around for more than one year it is probalby lost most of it's nitro content. Fuel with say 5% nitro will make .049's hard to start and un-reliable.

A large spinner or old un-balanced propeller can "foam" your fuel by making it vibrate badly. Usually this will manifest itself in the engine running out only half a tank. Mostly happens in the air though.

Try a new glo plug even if the old one glows with the battery.

Take out the needle valve and squirt some fresh clean fuel down the needle opening to flush out any dirt that might be in there.

Start your engine "sloppy rich" that is with the needle valve open 4 turns or so. You may have it set too lean to begin with.
As the engine starts s l o w l y turn the needle valve in 1/4 turn at a time or less and allow time for the engine to adjust it's rpm to the changes.
experiment, each engine is a little differnt with it's needle setting. Mine usually start at about 3 turns open, and run good at about 1+1/2 turns open.

[fychan]

Thanks for the tips, I'll give the ideas another run when I get some spare time...


In the meantime... I noticed a throttle controlled 0.049 come up on eBay recently - the first time I've ever seen one. Are they rare?

I've also noticed that the engines are almost twice the price over here in the UK than they are in the US. What sort of price should I be looking to pay for a 049 throttle controlled engine... Does anyone know what a sensible bid would be?

[John1963]

Your fuel tank has to be vented so the reed will raw fuel properly.There are several tanks that will work that can be found in habby shops.If you can find a 3/4oz to 1oz Perfect brand wedge tank or one of there square tanks it should cure your problem.Watever tank you decide on "IT MUST BE VENTED!"Pm me and I can email you an article on fuel tanks

[Anders]

I got my old cox engine running today
I was mounted on a all plastic fokker dr1, line controlled aircaft.
I got the plane from my dad when i was 8 or something, and back then i opened it and left it outside and took really bad care of it. that`s somthing i ve always regreted, but today i decided to open it. and finally i got it up`n running
I will build an Rc plane to put it in, but i`m not sure if i will put it in a guillow`s plane or make my own plans..

Anyone of you which have some experience in putting fuel engines/cox engines in guillow`s planes? And wich of them suits a cox engine best? (don`t know what sice it is, only that it is a cox engine, and the plane it was in is adout as big as a 500 series guillow`s plane)

[flash52]

A brand new Cox .049 will need a minimum of 3 tanks of new fuel set rich to get it broke in. You'll know you are done when it will hold a steady rpm. You didn't say what prop you are using. I always had good luck with props from 5-3 to 6-4 size. 6-4 and larger the engine starts to bog down. If your needle is set too lean it will over heat and stall out before the tank is empty. 2 1/2 turns open to start, then open slowly until it slows down. You should be smoking with a lot of oil coming out of the exhaust ports. It should have a burbleling sound not a high pitched shrill if its set right for break in. A dependable little motor after it's broke in. Follow the previous advice on tank placement,nitro content etc. Good luck


Flash

[flash52]

Anders

The 400 series works well with the Babe Bee .049 if you keep the plane light. From your description of the plane size It sounds like a Pee Wee .020. If the glow plug outside diameter is 19mm its a .049. Smaller size would be a .020 . 300 and 700 series works well with the .020. Make sure you use a hot fuel proof dope or something similar to fuel proof the engine compartment as raw cox fuel makes excellent paint stripper.

Flash

[Anders]

Thanks for the help, had some problems with the engine since the needle on the needle-valve is broken, but i finally managed to use a piler to adjust it. The engine has been running some 8 years ago so running in is not needed( i use my OS 46La manual to get the correct words).
I found some plans on the internet for cox engines, and out of the plans i think it is a Cox 0.49 Killer bee.
And my dad told me that a 60 cm plane would be siutable for the engine. 2.5 cm is 1 inch for those who don`t knew that ( i use cm when i measure).

Thanks again for the help. i think ill make a FROG HERON to put the engine in, its originally a competition rubber model from early 50s.
but when i fell ready for it ill make a Guillows scale model for it
(a hurricane i think).