That definitely looks like a "set it and forget it" flapper. That's based on the setscrew and lock nut in the first pic. It looks like the divots are there for positioning the flapper for various conditions. The military probably wasn't too concerned about fuel economy.


Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.