when the weather gets cooler i'm finding that i have to run my engine much richer for some reason and i'm burning 10% fuel. i'm wondring if changing to 15% would let me run it a bit more lean because its running warmer.

15% would require you to be even more rich

Cold air has more density so you need more fuel to maintain the stoichiometric air-fuel ratio

Nitro has a lower stoichiometric ratio than Methanol. Therefore a greater percentage of nitro - you will have to open your needle valve more and get less economy.

You are probably NOT actually running richer. Cold air is more dense and carries more oxygen. To compensate you needed to open your needle valve a bit more to obtain the SAME fuel to air ratio as before. Because you opened the needle you probably though you were making it richer but actually just returning it to where it belonged.

so your suggesting that i stay to the 10%?......what are you using?

I've used 15% winter summer for the last 4 years but I generally run four strokes

it seems with the way i have tuned it now that i can't the rpm's to where they are when its warm

well i just run two stroke engines.......i just got into this so i got a lot of learning to do

The engine actually will make more power if you get the mixture right.
The last time I flew the temperature was around 36F at the beginning of the day and got up to about 54F. Those engines really ran good when you let them warm up a little.

i'm really appreciating your help here w8ye..............you seem to have been around. glad i joined this forum

so you guys do much flying in 0 degree celcius temps

You build models 55 years and you will have a lot of the answers too.

We try not to.

your a funny guy bruce............but when you live in canada the flying season would be too short if we didn't

I used to before I was 30 but that was a few years back. If I get out there now in the 30's it's supposed to get up in the 50's by mid day. I lived in Alabama for 3 years in recent times and that's the usual temp in the dead throws of winter. Fly all year down there. The flying is done for me here in Ohio until March

This is supposed to be fun. Freezing is NOT fun. Many in the Northern states do fly in the cold. Here in my part of Tennessee the cold doesn't last long enough to count.

ok bruce, hang on.....i'm comin down there

Did I mention the 100+ degrees fahrenheit summers?[:@]

I remember being down south in July. Absolutely perfect flying conditions wind and rain wise but the Temperature in the high 90's and no wind with 90% or higher humidity. Hard to get your breath at times.

Thank goodness I could set in the shade of a building to fly.

Yep, Houston (lived there for 10 years) is about the same as here except hotter and more humid. Both feel like a steam sauna in August.

Sure, if its a nice day. Engines run better with more power and the planes fly better. Just get some good gloves or a transmitter mitt to keep the wind of your hands. Lighter fluid is helpful to start the engine. Batteries won't last as long in the cold though.