Cold weather help please
 

I live in MA and its about 20 degrees here now. Kinda windy and freezing but I still want to fly!

I've gone a few times and I've been the only one at the field. A few times I was unable to even start the plane. Now I leave the plane inside overnight to keep warm and start it in the driveway to make sure it will be ok. Now even if it starts it won't run right. It will idle and I can creep up the throttle and let it run to warm up. No matter how long I let it warm up it will not transition off idle. Any small blip in the throttle and it stalls out.

I'm a total noob so I need needle advice. I ran the plane all summer and it ran great. I need help setting the needles for cold weather. There's one needle external (high speed top end needle) and one on the side of the carb which I assume is the low speed needle that I need to adjust.

Can anyone point me to a good thread or walkthrough to set the mixtures right?

Also I need to know some tricks to start the engine. Normally it will not start unless I pinch the exhaust tube for a while during cranking over. I see guys blocking the carb intake and then giving the prop a spin with no glow ignitor, then starting by hand and it works. For me I drain the battery on my starter and it takes over 30 seconds to get the engine to start every time

Engine is an OS 46FX

Thanks
Tony

RE: Cold weather help please
 

Cold air is more dense than warm air (read: engine will be lean). Moist air is also more dense than dry air (read: engine will be lean). You will probably have to retune both needle valves. Be careful to not overprime the engine. Cold fuel will not vaporize as easily or quickly as warm fuel. Warm the engine and fuel inside your car before attempting to start it. WARNING: Do NOT heat the fuel with a direct heat source. You might need to experiment with a stronger glow plug lighter or a hotter glow plug.

Don't give up. It can be done. I've flown one of my sport planes on skis in 6 inches of snow. I'm sure pilots who live farther north of me (SC, sunny south) fly in cold weather, off snow, and in other extreme conditions, and will have some good advice.

Dr.1

RE: Cold weather help please
 

Hi!
Sounds like the Weather we have here in Sweden just now.

If your engine stops or hessitates when you give full throttle it's the idle needle that is set too lean ...just open it up a quarter of a turn and you will see that the engine will work ok.

Regards!
Jan K
Sweden

RE: Cold weather help please
 

To start! some use a couple drops of lighter fuel in the carb.

roltech

RE: Cold weather help please
 

Forgot to mention use a #3 glow plug "hotter"

roltech

RE: Cold weather help please
 

if you quickly increase throttle to full and it shuts off, your low end may be too lean. if you quickly go to full throttle and it bogs then shuts off your low end may be too rich. Check that. Also if you slowely transition to full and its not running right you may need to tune your high end then check the low end. Hope that helps.

I forgot to mention, Also get a OS #8 Plug those work the best. Make sure your fuel line is good and make sure your fuel tank is not leaking.

RE: Cold weather help please
 

Depending how cold it is #3 is a hotter plug than #8 I found that #3 works better for me in cold weather.

roltech

RE: Cold weather help please
 

Yeah I know how you feel. I'm keeping things grounded until spring comes. I have a sim, I'm all set for a while. Once it gets warm I get maiden my 1/4 scale CAP.
So where do you fly? Seeing as you're in tewksbury probably with the 495th? If so good luck with them guys :eek:

RE: Cold weather help please
 

Yeah I fly at the 495th. Why the :eek:? Every club has a few knucklheads of course. I think the officers of the club do a great job. The instructors are all awesome and every member has been super helpful whenever I needed anything. They run fun events and I always have fun at the field. Just curious.

RE: Cold weather help please
 

My electrics are not affected by the cold. I fly in Northeastern Ohio all winter long. Have skis on both my planes.

RE: Cold weather help please
 

;)I have flown this winter in the 20's temp wise.All I had to do was go to a higher nitro content.I went from 10% to 15% and retuned the high speed needle.It worked on my 2 and 4 strokes.Also helps to prime engine by turning over by hand with the throttle open with thumb over the carb opening and NO GLOW STICK attached.Let it warm up a little longer before you take off.Good luck and hope some of this helps.[X(]

RE: Cold weather help please
 

Here's a little trick I do when it's cold:

Leave your car running.

Set the plane on the ground so that the engine is sitting beloe the car's exhaust pipe and the hot exhaust is blowing directly on the engine.

Sit in the car and stay warm.

DO NOT BACK UP :D

After a few minutes, the engine will kick right over.

RE: Cold weather help please
 

Ditto to what minnflyer said. Just make sure you keep an eye on things so that the covering doesn't melt off. Obviously, this tip doesn't work real well with cowled engines.

-Scott

RE: Cold weather help please
 

The warm exhaust can even find its way into a cowl... Just don't melt your cowl

RE: Cold weather help please
 

Fair enough. Come to think of it, I've never tried it on cowled engines.

RE: Cold weather help please
 

Just a clarification. Moist air is LESS dense than dry air.

Dry air is mostly diatomic Nitrogen - wt= 28
some diatomic oxygen - wt= 32
a percent or two of other gases.

MOIST air is the above with the addition of H2O
2 hydrogen = 2
1 oxygen = 16
Total wt/molecule = 18

replace any of the molecules in dry air with water, and the density goes DOWN.

I've found flying here in MN, I've been okay just opening the high speed up a bit to compensate for the increased air density. It also REALLY helps to keep the fuel warm - I just keep it inside the home then the car - some people have actually warmed the whole jug in a tub of hot water.

Tim

RE: Cold weather help please
 

Just adjust the high end needle counter clock wise about a half of a turn. What I normal do is close it and than adjust it to 1 1/2 to 2 turns. Start the engine with it rich and adjust the high speed only until it runs right. I fly @ the Groton field and have no problems with the cold weather. I am flying with the same engine.

RE: Cold weather help please
 

Well mystery solved.... It wasn't the cold at all really. I use one of those fuel filler valves that mount to the side of the plane to fill the tank. Its a spring loaded valve that allows you to fill cowled engines without pulling tubes off. Anyway this one was stuck open a bit and was letting air in, thus running super lean. One of our instructors was kind enough to give me an engine tutorial and he found it by blowing into the muffler vent tube and we expected to see fuel pour out of the carb. Instead it poured out of the side from the valve. Remove valve and replace with tubing and bingo, she fired right up.

That's one for the lesson books