Winter Flyer
 

Hi,
I am trying to fly in the frozen North Dakota. While my Alpha Trainer starts without fail, when I run the engine up after about 30 to 40 seconds the engine starts to stall. If I take it in the air it happens even faster. I checked the engine (Evolution .40) according to the book and have the right mix and increase in RPM when pinching off the fuel lines. I have skis on the plane and have done fine in warmer weather like 25 to 30 degrees. I have switched to a 30% nitro and did a little better, but I still have loss of engine power and have to dead stick it in after about 3 or 4 laps. Anyone else fly in the [&:]"COLD" sub zero temps that can help? Thanks ahead of time.

Lefty[sm=thumbup.gif]

PS. The Alpha Trainer .40 is a great first plane. I have had great success with it. As for the occasional crash It was minor enough that I was flying again the next day.

RE: Winter Flyer
 

Sounds like engine is getting to cold. Might try wrapping part of cyl with alum foil that should help keep engine warm on really cold days.

RE: Winter Flyer
 

I agree with the cold engine reason. Down here in Oklahoma, it doesn't stay cold for long, so on those days that I fly in the cold, I wrap the fins of the engine with some aluminum from a pop can to keep the heat in. It does seem to help. I have a infrared thermometer and I use to get readings of about 175 degrees right after landing on a cold day. I've read that a good head temp should be closer to around 350 F.! This is for a ABC engine, not too sure about the ringed types. Try it and see what happens. Let us know.

Jesse

RE: Winter Flyer
 

I have seen this problem as well when I flew glow. Another solution is to use a plane with a cowled engine in which you can close of the air flow directly over the engine.

RE: Winter Flyer
 

Definitely the engine getting cold. Wrapping a layer of aluminum foil around a couple of head fins seems to work. And yes, you want a head temp of about 300 to 350 F.

The problem is, the air is so cold that your engine can't provide enough heat to keep itself warm, and the glow plug eventually gets too cold to stay lit. The cold fuel and cold air entering the cylinder "puts out the fire". ;)
Dennis-

RE: Winter Flyer
 

Why not try one of those onboard glow plugs things. Maybe that would work??????

RE: Winter Flyer
 

OK,
What are on board glow plugs and do they make them for an Evolution engine?

Lefty [sm=thumbup.gif]

RE: Winter Flyer
 

If you want, just put a 1.5 volt battery in your plane and hook it to the glow plug to start the engine. leave it on and fly.

RE: Winter Flyer
 

What Geistware said. An onboard glow driver is a battery wired to a glow plug connector that you can permanently attach to your engine's glow plug. There's usually a switch wired in that you set up on your throttle pushrod so the glow driver gets "switched" on at 1/3rd throttle and lower. Your problem would require having it "on" all the time though, so I'm not sure how long the onboard battery would last.

Much easier, and cheaper to try some aluminum foil around the head. ;)
Dennis-

RE: Winter Flyer
 

The onboard should have a low value (high current) resistor in line if left constantly on. Full throttle + power to the plug can burn out the plug. I would take a resistance reading on a glow plug, and use a resistor of that value. (essentially providing .6 volts to the plug)

That combined with a bit of aiflow reduction at the cylinder head would cure the problem if its too cold.

Another possiblity.. carb icing. if there is the TINYEST amount of water in the fuel.. you will have ice form in the carb and the engine will die. The ice will melt before you get to the airplane.

BTW... flying in cold weather I used to use 25% nitro to prime the engine but still filled the tank with 10%. Just needed a little extra 'kick" to get em started. But I never flew in below Zero temps. (I hate being cold.)

I have flown when it was raining, snowing, sleeting.... Had to land once due to ice forming on the wings.

RE: Winter Flyer
 

None of the above guys. If your motor is a good runner when it's warm, then in cold weather it is pretty likely to be pure tuning. If it's cold, you need to run it richer, as much as a half a turn, maybe more than you do in the summer. You do not need on board glow drivers, or foil around the engine. I have flown routinely at 10 below and less frequently as cold as 20 below. No serious problem, and no motor modifications either, except for mixture tuning. The big problem is cold air is dense air, and dense air means lean runs if you don't retune, but it also means one heck of a lot more horse power out of your motor.

One other problem. In cold weather, the motor goes from Hot to MUCH colder that usual, and this can work loose the screws that hold the motor together. Your problem sounds like a classic loose carb or back plate. Thermal expansion or contraction are allowing air into the system somewhere it's not supposed to go.

So, do the following:

1) Tighten down every screw you can find on the engine.
2) Retune your motor to run richer in the winter. Make sure you really have backed off from that screaming lean setting. Let it break into 4 cycle every now and then
3) Also, run LESS nitro in the winter. Nitro is a catalytic inhibiter, and if a cold plug is really your problem, adding nitro will make it worse.

I run 10 or 15% in the summer, and no more than 5% from halloween until about St. Patick's day.

Carburetor icing CAN happen, but usually our carbs are so hot that ice can't form, anyway, it usually only happens when it is really cold AND the temperature is close to the dew point. I've only been able to make an RC carb ice up twice and only in conditions when the full scale pilots were avoiding the air because of icing condition.

You can get impact icing, but if you do, a shutdown of the engine is good news, the carb iced up before the airframe did, and you got the plane down rather than spinning it in. I've had impact icing on carbs and airframes, but that's from flying in snow squalls.

RE: Winter Flyer
 

Well I have tried the foil on the carbs and it worked marginally better, I am using 30% nitro as well. I will ensure that everything is tighter and let you know how that works. I really don't want to put a battery on board for the glow-plug. I'll let you know how it goes. Going to be too windy for about the next week or so, but I'll keep you posted...
Thanks all

Lefty [sm=thumbup.gif]

RE: Winter Flyer
 

I held a fellow flyer a week or so back and his OS40 could not get hot enough to burn my hand if I held it. The engine kept dying. My gas engine would be cool enough to touch after I landed, but ran great. We kept his glow driver connected (wire with alkaline battery) and it flew great. I am don't know enough to analyse why it worked, it just did!

RE: Winter Flyer
 

ctdhale is right on the money! If your plane flies good in the summer it will fly even better in the winter .I fly glow fuel and gasoline powered planes mostly during the winter here in montana and I've never had any problems other than cold dumb thumbs. Cold air= more lift, less nitro,richer needle setting.

RE: Winter Flyer
 

Its easy to explain.. the coold air and high velocity airflow cooled the glow engine so fast... it killed the glow. The gasoline engine had a spark ignition system and didn't depend on heat retention from one combstion cycle to fire off the next. Putting on the glow power and leaving it equalized the situation... you provided the heat for ignition despite the airflow cooling the engine.

Try copper-wire strapping some soda can aluminum onto the engine to prevent air from hitting the cooling fins... the engine will run without the glow driver. (careful... you can excessively prevent airflow and overheat the engine. and its possible to create RF interference....)

RE: Winter Flyer
 

I don't know the thermal mechanics but what you say sounds reasonable.

RE: Winter Flyer
 

From what I've read, the combustion chamber has to reach a certain temperature to cause the raw fuel to start vaporizing as it's being compressed. My own readings have indicated that my engines don't get anywhere near as hot as is necessary to accomplish this. ABC engines also need to keep their cylinder temps high to allow for proper expansion of the piston/cylinder assembly. I don't experience real low temps here, and I fly regularly in the winter. The most I have trouble with is the first start. After that, it's no big deal.

Jesse

RE: Winter Flyer
 

Well thanks to everyone, Since I have received so many great ideas the temp here in North Dakota has reached an all time low at -25. Wind chills continue to be way to cold to safely fly. I'll let you know.

Lefty [sm=thumbup.gif]