What's new
British Ordnance Collectors Network

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Spin stabilzed bomb?

Slick

Well-Known Member
I wasn't aware bomb spinning was a thing. This test drop from an F15 of a new and improved, adjustable yield, B61 bomb shows some pyrotechnics initiate a couple of seconds after release. BONUS FOOTAGE - loading it up. On the F15 note, I just checked and made note of the fact it first entered service in 1976. It has a 98-1 kill ratio. Not bad. Not bad at all.

https://www.youtube.com/watch?v=FBm74WiCL1g

Back to the spinning issue, when did they start doing this?
 
Don't forget the British 22,000lb DP "Grand Slam" and 12,000lb DP "Tallboy" bombs. Their fins were offset by 5 degrees, causing the bomb to spin during its fall, aiding stability and improving its accuracy, with a terminal rotating velocity at impact of no less than 300rpm!. The rotation obtained by the means of angled fins of angled fin tips was very common in ww1 (both German PUW and first French bombs used it) and interwar bombs (see for instance the Tolfvan/ Bofors bombs). Other means of stabilization such as tail rings (French, British, Italian, Soviet and German bombs) took then the lead. The US box type is more complex as some models may have been initially designed to give a measure of rotation (see for instance the fin shape of the M47 bombs, some early models their fins edge folded at right angle).
 
In Fleischer's book "German air dropped weapon up to 1945" I found info that according to German tests in 1920s-1930s P.u.W bomb have a serious stability problems caused by spinning too fast. They frequently fall in almost horizontal position (over-stability) or tumbling chaotically. In particular, when they were dropped from 4000-4500 m (12.000 - 13.500 ft) or higher, they usually break up in flight (by coincidence between aerodynamic and centrifugal forces) and only small fragments fall to the ground.
 
Top