Well its a 67 grain lead bullet, I think it counts as a lead pellet. Marko
9mm sabot .224 50grJust the sabotMarko
...Just the sabotMarko
Helium inline valve. I put the info in the other thread, it's repeatable, have shot usually three to five before posting any numbers. Marko
Actually, the MV is well over Mach 2.... At 70*F, it's about Mach 2.5....Bob
Quote from: rsterne on February 23, 2017, 10:36:01 PMActually, the MV is well over Mach 2.... At 70*F, it's about Mach 2.5....BobMaybe mach 2.5 in relation to the ambient air. But not for 3000+psi driving air. Closer to mach 2.Besides - it was HELIUM!SOS is over 3000fps for helium and probably over 4000fps for high pressure helium.I thought we were talking about maximum theoretical velocity in a PCP? With high pressure AIR. At ROOM TEMPERATURE.We need to stay withing constraints if we want to test theories.
LOL, Helium. I can cancel my appointment with my mental health professional now!
Actually, THIS thread deals with maximum THEORETICAL velocity, which depends only on pressure, bore area, and barrel length.... The gas won't matter, because the original formula doesn't take into account the mass of the gas, or ANY losses, assumes an infinite reservoir, etc.etc.etc.... The maximum theoretical FPE for Marko's gun (9 mm, 250 bar, 540 mm barrel) would be....(0.354^2 X PI / 4 ) x (250 x 14.5) x (540 / 25.4 / 12) = 0.0983 sq.in x 3625 psi x 1.77 ft. = 356 lbs. x 1.77 ft. = 631 FPE.... If the sabot weighs 1 g. (15.4 gr.) that works out to a theoretical maximum velocity of 4295 fps.... 54% faster than he achieved.... so no laws of physics have been broken.... Using Lloyds spreadsheet, and including the mass of the Helium in the bore, the efficiency is only 69%, so no magic there.... Changing to air, with no other changes, it predicts 1668 fps....Bob
Quote from: Scotchmo on February 24, 2017, 03:54:53 AMQuote from: rsterne on February 23, 2017, 10:36:01 PMActually, the MV is well over Mach 2.... At 70*F, it's about Mach 2.5....BobMaybe mach 2.5 in relation to the ambient air. But not for 3000+psi driving air. Closer to mach 2.Besides - it was HELIUM!SOS is over 3000fps for helium and probably over 4000fps for high pressure helium.I thought we were talking about maximum theoretical velocity in a PCP? With high pressure AIR. At ROOM TEMPERATURE.We need to stay withing constraints if we want to test theories.what does it matter what the sos of the gas is? the pellet was moving mach 2 plus.
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