always wanted to know
 

why don't turbines die or run poorly when they do through a ton of clouds/rain? would model turbines withstand moisture like the big ones?

RE: always wanted to know
 

Hmmm, well, I'll make a guess at this.... Let's say you're flying through a cloud and your engine is ingesting a certain volume of air...in that air, only a relatively small percentage of that total volume of air is actually water. Imagine if you took all those miniscule water droplets from the cloud and condensed them... I'm guessing you would end up with very little water. Remember a cloud isn't only water droplets, it's water droplets suspended in air.

Similar story for rain...the engine is ingesting many hundreds of cubic feet of air, of which only a small portion is liquid water.

I imagine if you put enough water down the intake the fire would go out, but I saw a show on TV about the testing the engines for the Boeing 777 had to be put through. They were run on the ground and water was sprayed into the intake at the equivalent of a tropical downpour... not even a hiccup.

That's it, that's my guess!

As to whether RC turbines would do as well...couldn't tell you, but I imagine they'd stay running in conditions that would have me running for shelter.

RE: always wanted to know
 

Elec,
Most turbine engines today are considered medium to high bypass. This means most (70%+/-) of the thrust is developed from the fan, or the big turny thing you see sitting at the gate as you are waiting for your flight. So about 70% of the air is going through the bypass or outer "core" of the engine. The other 30% goes into the core and does numerous things include sustain engine operation among other things but we wont get into that. The core air is compressed through several stages, mixed with fuel and burned, hot gasses expand over turbine wheels to extract energy which in turn drives the compressors. This is one continuous evolution. So power is determined by fuel scheduling rather than air metering in the big picture. Well, during air compression, the air gets so hot that any moisture present is usually so far gone it doesn't matter. Another thing is when turbine airplanes fly into rain, etc..., they usually turn on there ignitors which keep the engine from flaming out. Think of these things as SUPER spark plugs. There are usually at least two and they alternate about once every half second. Very loud when you turn them on with out the engine running. SNAP SANP SNAP SNAP. They will most definately hurt you!!! Some of these turbines run as hot as 900 ITT degrees centigrage during start. When I start a Lear 60 I see about 300 degrees centigrade just before light off from compression alone. Usually the engine lights off around 320-350 degrees. She will spike to about 900 during start and settle back down around 500 at idle. Hope this helps I tried to be as simple as I know how!!

RE: always wanted to know
 

Good job there Nick.Thanks.

RE: always wanted to know
 

Nice one Learjetmech
here's another thought.
most engines run better in cold, damp air. Cold air is denser than warm, so more oxygen gets into the mix for a given volume of air = more power.
In damp conditions the fuel has a tendency to coat the water droplets . This has the effect of increasing the surface area of the fuel droplet as compared to when it is a single, solid droplet. Makes it burn faster - gives more power!
This latter characteristic was exploited in the fifties especially by Boeing with water injection into the likes of B-47s, early model B-52s and KC-135s. It was this that created the huge clouds of black smoke left on the runway at take-off.
hope this was of interest.
cheers
R

RE: always wanted to know
 

I just want to know what " the big turny thing" is?

RE: always wanted to know
 

Ahh, the "big turny thing"! I was referring to the N1 compressor or more common term of "the fan". I hope you were serious!

RE: always wanted to know
 

Was just being silly. I get that way sometimes. I think it is because I buy Zip kicker in the gallon size. (:

RE: always wanted to know
 

cool vid on here of trip through an jet engine.

http://www.rolls-royce.com/education...ney/flash.html


Grinder.

RE: always wanted to know
 

Rain past window on an Herc flying through an Hurricane.

http://www.hurricanehunters.com/rainprop.mpg

Grinder.

RE: always wanted to know
 

Heavier rain past window. Man those guys are crazy.

http://www.hurricanehunters.com/hvyrain.mpg

Grinder

RE: always wanted to know
 

Model engines will take a moderate amount before getting disrupted.