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Tom West's Custom PC77 PumpMaster Classic Short Rifle



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Transonic Drag

August 20 2012 at 10:13 AM
rsterne  (Login rsterne)
from IP address 66.244.241.34

I found an interesting graph on Transonic Drag that I thought was worth sharing with you....

[IMG][linked image][/img]

Note that the drag starts to rapidly increase between Mach 0.80-0.85 (900-950 fps) and has doubled by Mach 0.9 (1000 fps) and tripled by Mach 0.95 (1050 fps).... This means that the extra energy it takes to get a pellet above 950 fps will quickly be shed in the first few yards anyway.... That ties in exactly with the work I have been doing on how the Ballistics Coefficient changes as you push the velocity close to the speed of sound....

Since 950 fps gives you an energy of 2 FPE per grain of pellet weight (an easy number to remember).... this is just one more reason not to push the velocity past that....

Bob

 
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