Clearing up some confusion about the Fowler Flaps and Dive Flaps on the P-38L

[DaveBB]

The dive break was made to fit the specific job.  Some aircraft only dove at a 20 degree angle (glide bombing it was called), others at a 70 degree angle.  Hence the different sizes.  The SBD, SB2C, A-1, and A-36 all had big dive breaks.  They were all designed to attack at a steep angle.  Fighter bombers and other aircraft weren't designed for such aggressive bombing (though that does not mean they weren't used for that purpose).

[colmbo]

Just a reminder the drag is proportional to the square of the velocity.

https://www.grc.nasa.gov/www/k-12/airplane/drageq.html

There were some aftermarket speed brakes for the Mooney GA airplane.  They were small plates that extended from upper surface of wing, small enough that at approach and climb out speeds they had virtually no effect on performance but when used at speed during a descent they worked quite well.