Slow it down: F-105 engine’s rear panels aren’t for style

Many think that the “clover leaf” panels at the rear of the F-105 are part of its engine. However, they are there for another, actually opposite reason.

They help slow the Thunderchief down during landing and during dive-bombing runs. The four-petal speed brakes can be deployed hydraulically, up to 90-degrees, all together or in pairs. The vertical ones only work when the plane’s landing gear is up. Otherwise, the top segment would block the brake parachute and the bottom one could touch the ground. In normal flight, the pedals became part of the plane’s smooth and efficient airframe. When the F-105 was in afterburner, the pedals opened slightly to allow the quicker escape of exhaust gasses.

Cory Graff is the military aviation curator at the Flying Heritage Collection.