q8cub

It is starting to get hot here in Kuwait as we are getting highs of 40-43 C and lows of 28-30 (very early in the morning).

What weather temperature is considered "too hot to fly gas engine planes" if there is such a thing? Assuming the engine is a DA-50 and inside a cowl well baffled and there is a louver to allow optimum air cooling in a size 50cc yak.

w8ye

My Feedback: (16)

If you can take it so can they. Make sure your mixture is set correctly.

q8cub

Well, as long as it is less than 37 C I guess it feels comfortable to be outside. By mixture, do you mean the oil/gas mixture ratio? And should I increase it more than my usual mixture as it is 40:1 redline according to DA-50 manual.

Also, would hovering be considered safe in such hot weather?

Thanks

Charlie P.

Not according to some of our club members. Though no less safe in the cool weather than the hot. They claim you're an obstuction of the runway and defying "the pattern". ;-)

Warm air is less dense and you may not have the lift. Also, less air density means you may need to lean out your needles.

w8ye

My Feedback: (16)

40:1 using Redline is fine for any weather.

I was talking about the Air - fuel ratio and the mixture needles

q8cub

I Bought the plane used but it was almost new, as it was flown just enough to break in the engine. I did not change the needle setting since then. By the way, there is black residue always coming out of the muffler and it accumulates on the tip of the muffler outlets (pitts muffler). Someone told me that a DA-50 should not do this when he noticed my plane had some traces of oil on the body of the plane (not much but I have to clean it at end of day).

MetallicaJunkie

sand or dirt being ingested by the carb would be my biggest concern.... down in south texas it can get hot, easliy in the triple digits, the killer is the high humidity...it really makes you sweat.

ive been to las vegas a few times in the peak of summer, i remember it was 112 one day, but it didnt feel so bad because it was a dry heat and i didnt sweat

pe reivers

For the same cooling effect, engine temperature has a certain well defined difference with outside air temperature. If cooling is just so so adequate like 185°C engine temperature  in 20° outside temperature, you will fry your engine at 40°C, when engine temperature needs to rise to 205°C for the same amount of cooling. 200°C (400F) is the maximum considered for cylinder lubrication. Many engines suffer above 150°C.
In high environmental temperature conditions, it is wise to do all you can to get proper cooling. Model engines have chainsaw engine size cooling fins. A chainsaw however has forced cooling by the flywheel fan and tight engine shrouding. Our engines have not, so in most cases the amount of cooling air through the fins is too small. This is compensated for by higher engine temperatures.

AJsToyz

Don't worry about the oil residue, it's probably not fully broken in yet. If they followed DA's manual break in is 2-4 gallons mixed @ 32:1 using mineral oil and running slightly rich. After that they have other recommendations.

http://www.desertaircraft.com/manuals/50Manual.pdf