wuzak
Captain
I was just looking at this report and found an interesting table on the effect of cowl flap operation on speed.
This is a significant drag rise for cooling purposes.
I guess if the engine can stand extra temperatures for a few minutes that keeping the cowl flaps closed would help in trying to evade a pursuer, but not if it means the engine melting over enemy territory.
Is there any data with regard to radiator flaps such as on the P-51, Spitfire or Mosquito?
Later radial engine types used different systems, like the cowl ring, which provided the same function as the cowl flap but without sticking into the air stream.
| Cowl Flap Position | Cowl Flap Opening (in) | True Speed (mph) | Speed Loss (mph) |
| Closed | 0 | 284 | - |
| 1/4 Open | 1-5/8 | 278 | 6 |
| 1/2 Open | 3-1/4 | 264 | 20 |
| 3/4 Open | 4-7/8 | 249 | 35 |
| Wide Open | 6-1/2 | 236 | 48 |
This is a significant drag rise for cooling purposes.
I guess if the engine can stand extra temperatures for a few minutes that keeping the cowl flaps closed would help in trying to evade a pursuer, but not if it means the engine melting over enemy territory.
Is there any data with regard to radiator flaps such as on the P-51, Spitfire or Mosquito?
Later radial engine types used different systems, like the cowl ring, which provided the same function as the cowl flap but without sticking into the air stream.
