Hurri D

[Pooh21]

More gv busting updates. Was flying my 109G-10 tonight with just one 30mm went diving on an m-16 to distract him, figured what the hey, fired off a 3 round burst in his direction to get his attention as I pulled up. I saw no hit sprites, closest one landed maybe 5 ft away. I roll around, Boom! System you killed mudmonkey.

[Tony Williams]

Originally posted by whgates3
Anyone know if Denys "Kill 'em" Gillam is still around - He is probably as much an authority on the IId as anyone. Here is what he said about it in Douglas Bader's book "It was deadly accurate, and we vied with each other to achieve the best results...The recoil from theses large-caliber cannons was tremendous and reduced the speed by 40 to 50 miles per hour".
I would think that the only way the cannon could be accurate & have that kind of recoil would be if they fired concurrently (not to mention the types of spins you would get into if one wing suddenly dropped 50 MPH).
He goes on to state that the Hurricane did a great job at absorbing punishment, himself taking large calliber directs hits more than once and flying home

Hmm. Let's do some simple maths. The 40mm fired a 2.5lb shot at 2,000 fps - so two together fired 5lb at 2,000 fps. Multiply those figures together to get a momentum index and you score 10,000 (the units of measurement don't matter as long as they're consistent). Then consider that the Hurri IID weighed around 7,000 lb. Divide that into your 10,000 and you get 1.42 feet per second recoil force on the Hurri. Consider that at an attack speed of 250 mph, the Hurri is travelling at 370 feet per second and you will see that knocking 1.42 fps from 370 won't make much difference. To put it another way, multiplying the weight by the speed of the Hurri (in fps) gives you a momentum factor of 2.5 million - that's 250 times more than the recoil. A series of four pairs of shots might knock up to 10mph from the speed, and that's on the generous side.

The Hurri's biggest vulnerability was to flak, as it couldn't carry the armour plate required to give it protection.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Discussion forum at: http://forums.delphiforums.com/autogun/messages/

[whgates3]

Ja, that phyisics makes a lot of sense, except that the gun is not 100% efficient, so maybe make it 12 MPH.  Gillam probably didn't earn his deadly reputation by keeping his eye on the air speed indicator when he was firing his guns.  Bet it feels like 50 mph worth of recoil though, especially when firing in a dive.