(question) Too (?) quick response to cowl flaps in flight

[scoobie]

I was looking for a similar thread, but couldn't find anything.

 

While I have learnt to deal with cowl flaps in Dora, there's one thing that makes me scratch my head.
I'm not claiming it's a bug or something, I just don't understand the thing.

 

On the ground, you may close/open cowl flaps and have to wait a while until you see influence on coolant temperature. That makes sense to me.

Now, in the air, when you "tune" cowl flaps to set coolant temperature at around 100°C, it takes literally 2 seconds for the temperature (as read from the temp. gauge) to jump up or down by a few dozen degrees Celcius. YES, I'm aware that lots of air is now flowing through the radiator (unlike when on the ground), but still... the response is so crazy fast. How's that possible? Only part of the water is in the radiator at a time, the rest is in the engine, hoses etc. Water can't flow through the circuit with at a "waterfall rate" (I think) because the radiator is made of tiny tubes etc. Even the very thermometer (coolant temp. sensor) - its response must be very fast to indicate such abrupt changes in temperature, so what did they use? I don't know what sensors they were using back in the day, but it IS very fast. I know thremocouples can be this fast, but they're rather difficult to use without "proper" electronics. Nowadays not a problem, but in 1940's? I don't know.

 

My head's spinning.
I know it may be all rubbish, what I'm saying, but where am I wrong? Can the the cooling system be this quick?

 

[grafspee]

Radiator capacity is 115 liters.

You want as high coolant flow as possible so engine temp will be even. At low flow coolant inlet would have to me extremely low let say 20C so the outlet hits 100C, so back of the engine has 20c and front 100C that would not be good for engine

Coolant flow is high to keep engine temp even, so expect that cooling system will be quite effective, opening cowl flaps to max will result in rapid temp drop.

 

Edited July 2, 2021 by grafspee

[scoobie]

Oh, OK... so it's high flow that does the trick. The temp. difference argument makes a lot of sense (thanks!).
It just felt so, you know... super quick, hence my question.