Nursing a damaged aircraft to safety?

[TinyTim]

Originally Posted by bladeracer

I've never seen any measurable drag from opening the radiator flaps so I don't know if closing them reduces drag at all.

Then it appears you've never been in a race for your life with an enemy AC of very similar top speed chasing you. Like running away in a Fw 190 D from a La-7. Opening and closing rads is a matter of life and death in such a scenario.

In my humble experience, the difference in top speed between open and closed radiators amount to somewhere between 25-30 kph top speed difference.