Heat and performance. Myth or fact?

You should look into the development of the P-38.

 

So like this. ^^

 

What is going on here? Ok so theories about power and operating temperature not based on the Internet, here we go.

Cold air is more dense, more O2 per volume -> more fuel can be added before hitting fuel air ratio limits.
- once engine/transition is warmed up the parasitic friction loses are similar to any other ambient temperature
- if you are talking about power from a stop or at low speeds the higher drag doesn’t come into play so just feels like more power

Hot air is less dense, so a bit less fuel before FAR limit. But power draw from other systems is also higher: AC compressor, cooling system (got to push more water through the radiator to keep engine temp acceptable).

Finally if the cooling system is not able to keep up, for various reasons, they will derate the engine by reduced fueling as a last effort for thermal management. Not sure what it takes to get to a derate, but i assume it’s not common.

 

What about the knock variable?

Higher intake air temp with a given fuel octane rating (say 87), and under high load conditions, wouldn't there be a greater possibility of knock? The ECM will pull timing in the event of course, which would reduce power as well..

 

I remember many moons ago. At Phoenix Airport, ATC did a ground stop since temperatures were really really high. Lots of delays!

 

Me too. I'll give this channel a whirl.

I saw one in person out in CO Springs. Pretty cool plane. Since this thread is already sideways here's some pics I took.



Turbo from a P47! At the very bottom you can see a turbo from a semi truck to give you scale for size.

 

Most recently it was like 12 moons ago. It was on the news because temps on the tarmac got up to 120°. I think it happens every year, but news is news. Much like the dust storms that happen here every year, suddenly one looks cool on the news and now my phone tells me that a dust storm is coming. My eyes do the same thing, but now my phone makes a noise.

 

When it was 100 degrees the other day i ran the ac....i noticed an immediate loss in power...my truck ran much differently. Seems it has at least 20% more hp with the ac off.

 

What about UFO’s?

 

Wouldn't put it past our military, or the cia to put out some propaganda that were seeing all these ufo's flying around our bases and ships claiming we have some special top secret weapons aliens are interested in.

 

Aliens yes if you mean: Russia, China, N Korea, Iran…

 

Not at all. Air temperature and density have a whole lot more to do with the aerodynamic performance of the plane and engine than just simple fluid temperatures. The electric engines still require cooling anyway.

 

Well battery cooling is obvious. So is motor cooling but not as many parts to monitor as an ICE engine.

 

To form a carb ice you need a moisture present, not a cold temperature.
Once I got carb ice while taxing at kbfi at 50+°f weather. If iirc, can happen up to 70°F.
"You want your fuel warm because it vaporizes easier as the temp increases, to a point. You don't want vapor lock."

Vapor lock is eliminated on fuel injectors system with submerged fuel pumps.

 

Thanks for the info. I’ll add it to my tool kit.

 

It is cold air intakes and higher octane fuel. Aliens are after that 0.5% uplift for their spaceships.

 

I thought they wanted the snorkel. You know? Traveling though the asteroid belts sucking in little meteorites can be harmful to their propulsion unit.

 

Definitely not a myth but it has a bigger effect on turbocharged machines since the turbos love cold dense air. Dyno a car on a cold day at low elevation versus on a hot summer day at high elevation and the horsepower numbers will speak for themselves.

 

"Just out for a rip are ya, bud?"

 

Air Temperature and altitude have a lot in common with NA IC engine performance. Ask this question in Denver (Or better, Leadville ) On a 100 degree day.

I saw that Salt Lake had high 90s and 1% relative humidity the other day. Extreme!