JasonC Posted July 26, 2006 Share Posted July 26, 2006 SteveP - typically one round is physically longer and burns a lot more propellant. The bore diameter, and the weight of the projectile that leaves the muzzle, do not tell you everything. I've seen stats on e.g. the German 20mm Flak vs. the Russian 20mm, and the German round was half again longer, burning a lot more powder, and thus developing a much higher muzzle velocity. In the case of US 37s, one is designed to be an antitank gun and punch through armor, the other was designed to fire proximity HE to damage relatively soft-skinned aircraft. Why would they be the same, just because they have the same bore diameter? A German 75mm on a Panther isn't the same as the US short 75mm on a Sherman, either. Diameter tells you little, the real figure is the muzzle energy. 0 Quote Link to comment Share on other sites More sharing options...
SteveP Posted July 26, 2006 Author Share Posted July 26, 2006 Originally posted by JasonC: In the case of US 37s, one is designed to be an antitank gun and punch through armor, the other was designed to fire proximity HE to damage relatively soft-skinned aircraft. Ah ... this might be getting toward an explanation I can understand. Certainly I was struck by the fact that the AA gun's HE shell produced a unusually high BV for a gun of that size. Keep in mind that we are talking about two guns of identical diameter and identical length. Are you saying that when a gun is primarily designed to fire HE shells (to look at it from one perspective), it might be optimized for that function in some way (do you know what that would be) that made it less effective at producing a high muzzle velocity when switched over to firing AP shells? Would this have been true of the 88 Flak, for example, in 1941? Related observation: Would I be correct in assuming that the reason why, in so many guns, HE shell muzzle velocity is significantly lower that AP shell velocity, is that more of the HE shell is filled with explosive charge, and therefore less room is available for propellant? Is there not also some similar considerations with respect to some types of AP ammo (that's a question, not an assertion)? Does that mean guns which are designed to be distinctly multi-purpose (e.g., the T-34) are essentially compromises, in which performance for any one purpose is somewhat hampered as a result? 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted July 26, 2006 Share Posted July 26, 2006 Originally posted by SteveP: </font><blockquote>quote:</font><hr />Originally posted by JasonC: In the case of US 37s, one is designed to be an antitank gun and punch through armor, the other was designed to fire proximity HE to damage relatively soft-skinned aircraft. Ah ... this might be getting toward an explanation I can understand. </font> 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted July 26, 2006 Share Posted July 26, 2006 Oh, bum. 0 Quote Link to comment Share on other sites More sharing options...
JonS Posted July 26, 2006 Share Posted July 26, 2006 Useful links: http://www.fas.org/man/dod-101/sys/land/bullets.htm http://www.fas.org/man/dod-101/sys/land/bullets3.htm And especially (in this context) this one: http://www.fas.org/man/dod-101/sys/land/bullets2.htm 0 Quote Link to comment Share on other sites More sharing options...
SteveP Posted July 26, 2006 Author Share Posted July 26, 2006 John D and JonS: Thanks for the education. I think you've pretty much answered my questions. 0 Quote Link to comment Share on other sites More sharing options...
Wisbech_lad Posted July 27, 2006 Share Posted July 27, 2006 "You can see why engineers aren't paid anything like as much as managers, lawyers and accountants, can't you? All the best, John." Heh, at present mining & oil engineers can pretty much write their own paycheque. When I was a student engineer, it was the oil & chemical firms that paid decent salaries for engineers. I actually spend 3 months as a production/ control engineer with P&G, and the pay was fine. Still, if you insist on doing something as NPV negative as designing/ building tank guns, rather than churning out chemicals/ pharmaceuticals - well, then it is a vocation, not a career... 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted July 27, 2006 Share Posted July 27, 2006 Originally posted by Wisbech_lad: "You can see why engineers aren't paid anything like as much as managers, lawyers and accountants, can't you? All the best, John." Heh, at present mining & oil engineers can pretty much write their own paycheque. When I was a student engineer, it was the oil & chemical firms that paid decent salaries for engineers. I actually spend 3 months as a production/ control engineer with P&G, and the pay was fine. Still, if you insist on doing something as NPV negative as designing/ building tank guns, rather than churning out chemicals/ pharmaceuticals - well, then it is a vocation, not a career... I have just stolen the following numbers from the salary checker at totaljobs. Obviously they are deeply questionable, first because they are based on totaljobs ads, and advertised salaries are largely imaginary, and second because the category names used are entirely misleading. The numbers are, in round thousands of pounds sterling, the reported "average" and "average maximum" annual salaries for each category. No, I have no idea what "average maximum" could possibly mean. Defence engineer:______32 to 35 Oil & gas engineer:____34 to 38 Solicitors:____________40 to 44 Accountants (ACA):_____41 to 46 General managers:______48 to 53 Doesn't look to me as if oil & gas engineers are doing terribly well against the bean-counters and the suits, and I expect barristers earn pots more than solicitors, it's just that they don't show up on salary surveys 'cos they don't get paid salaries. All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
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