Quote from: lloyd-ss on July 15, 2015, 11:20:56 PMDouglas, Is the name similarity a coincidence?LloydNope. Same with the Solar Impulse project.cheers,Douglas
Douglas, Is the name similarity a coincidence?Lloyd
Quote from: PakProtector on July 17, 2015, 06:54:16 AMQuote from: lloyd-ss on July 15, 2015, 11:20:56 PMDouglas, Is the name similarity a coincidence?LloydNope. Same with the Solar Impulse project.cheers,Douglas Wow ! Lloyd
At normal temperatures.At some point, the mass of the propellant overrides the mass the the projectile. Efficiency plummets and you run up against the velocity limit of the gas.Just thought I'd throw that in.Helium would allow a higher velocity.
Quote from: lloyd-ss on July 17, 2015, 05:53:52 PMQuote from: PakProtector on July 17, 2015, 06:54:16 AMQuote from: lloyd-ss on July 15, 2015, 11:20:56 PMDouglas, Is the name similarity a coincidence?LloydNope. Same with the Solar Impulse project.cheers,Douglas Wow ! LloydNo problem with the math but this has me totally lost
So many factors to complicate a seemingly simple process!I am very tempted to take an aggressively tuned Discovery, tethered to a regulated air supply, and shoot it across a chrony, sawing an inch off the barrel between each shot (or group of shots.) The delta v data would provide soooooooo much information. I hope this has already been done and that the data is available somewhere.Anybody aware of it??Thanks,Lloyd
Don't know if this will help ......http://www.network54.com/Forum/79537/thread/1418165148/2/Gaylord+%26amp%3B+DQ+max+velocity+test.The subject of high speed compressible flow is often misunderstood. And regarding the idea that Vmax = 1650.......an approach based solely on the principle of superposition, coupled with a bit of thought, easily puts it to rest. Ron
Theoretical maximums become a target that seldom prove unreachable
How would one factor in the velocity /inertia/momentum component of the propelling gas? Such as would be present with "typical" valve and transfer port configurations? Then too, there is the uncertainty of temperature. Expansion , friction and stirring. etc.
Quote from: Cal on July 19, 2015, 10:10:34 PMHow would one factor in the velocity /inertia/momentum component of the propelling gas? Such as would be present with "typical" valve and transfer port configurations? Then too, there is the uncertainty of temperature. Expansion , friction and stirring. etc.Believe it or not, there are equations that can be used for all that. It just depends on how deep into the Physics you want to get. But we don't calculate the theoretical maximum to figure out how a gun will perform (that's what engineering and trial-error is for)... we calculate the theoretical maximum to know what the absolute best is that we could get. That helps in making some decisions about calibre, pressure to use, barrel length, etc - and also helps to weed out bad chrony numbers that turn up every now and again (nobody's fault, just user/mechanical error).