Pe2 flaps

[Bilbo_Baggins]

Was wondering what's the story behind the Pe2 flap design? They extend to 50 degrees but it is prohibited to extend them past 35 degrees (70%) as the machine dangerously stalls out at the landing angle. 

 

Why was the machine made with excessive flap angle if it could only use 70% safely?

Edited August 16, 2020 by Bilbo_Baggins

[danielprates]

Not for me to answer as I don't know, but I would guess it was designed intended to work well but actual trials showed that the performance was not as intended. Redesigning was deemed to expensive or to incur unwanted delays, so intstructing pilots to limit the use to safe levels was the end solution.

 

One such issue which I do know about: the Avro Manchester's engines (the vulture iirc) were found to be prone to overheating and fires, but instead of redesigning (which would necessitate procuring other engine types which were unavailable) and taking the airplane out of action in a critical moment, they merely underrated the engine, capping the max power settings so it could not be horsed around. I would imagine the situation you mentioned is a bit like that.