It's hot and muggy---More nitro or less nitro? that is the questiom.

I've been feeding my B .40 5% nitro and 23% oil & castor mix. A couple years ago in the hot weather Jan and I postulated that less nitro would let the engine run cooler/better in hot humid weather.

What are your thoughts on this please.

It's hot and muggy---More nitro or less nitro? that is the questiom.

I've been feeding my B .40 5% nitro and 23% oil & castor mix. A couple years ago in the hot weather Jan and I postulated that less nitro would let the engine run cooler/better in hot humid weather.

What are your thoughts on this please.

Hi Frank

Most alway  we  go  up on nitro  when it gets into hot  months,
Reasons are, when it gets hot  and  humid , power  goes  down, in order to get it back some people  turn the needle in  leaner, this just makes for a  hotter  running  engine.
If you add  nitro, it give  more  power and  lets you  run the  needle at a  richer  setting  thus  not  making  the engine  run hotter. It also requires you to run more  fuel  thru the engine for the same  amount of  flight  time, thus  cooling it  more.

Regards

Randy

One advantage of nitro is that it actually supplies oxygen to the combustion process. On hot muggy days, there is actually less oxygen in each breath the engine takes. Without doing anything the mixture actually is on the rich side. Leaning it a bit will give more power, but since you are actually now burning less fuel and air, the power will be down compared to the same mixture on a nice dry cool day.

Adding nitro on that hot and humid day gives you that extra oxygen, so you more or less can leave the needle where it was on the cool day and have effectively the same mixture setting. So now your engine is happy.

Frank..

I knew you liked things backwards!!

Curt