Carl Schwamberger wrote:I always appreciate Rich, he keeps me honest.
An interesting comment on my pedantry.
Carl Schwamberger wrote:You got me there. I mis remembered the emergence of the M3 by over 18 months. However the September 1939 date for the first M3 casting is after the French had large cast tank components in routine production for several years. Also we need to keep in mind I was refering to 1939, not 1040 or 1941.
No, the casting by General Steel was September 1940, not 1939. Whether or not you referred to 1939 though is irrelevant. French castings were essentially static from c. 1936-1940...the same rather small and simple casting cranked out year after year for the designs already extant. Yes indeed it was routine for the French. You could also say it was stagnant. The General Steel casting was much larger and more complex than anything the French had succeeded with and it got better after that for the Americans. To be fair of course the French didn't have much chance to try to pick up the pieces after June 1940.
Mv is only part of the equation, another important part is the mass of the projectile. Of the weightiest US 37mm combat AP projectiles the M74 & M51 mass at .87kg. For the SA34/35 47mm mass of the AP is given as 1.67 kg. I'm sure you know the formula for finding the energy of the projectile as well as I do. I'm coming up with the 37mm projectile having about 76% of the energy of the 47mm projectile at the muzzle. There are a number of other factors that favor the larger diameter & mass projectile over the smaller. There are a number of sources for penetration of the projectiles. At the shorter ranges, under 300 meters the US gun seems to have 70 to 80% of the penetration of the Fr weapon vs face hardened armor.
The French gun had a penetration (at 30 degrees) of 39mm at 100 meters, 33mm at 500 meters, and 26mm at 1000 meters.
The American gun had a penetration of 53mm at 500 yards, 46mm at 1000 yards, 40mm at 1,500 yards.
The French projectile had more effect after penetration.
Dont be sorry, Which in 1939 is better than anything the US had. No matter how you cut it the M3 was a inferior concept to the G specification at the start and as it evolved.
Sorry Carl, but it seems you are saying a nonexistent French tank in 1939 was better than a nonexistent American tank in 1939. Let me say it again, no G1 prototype was ever completed and the project was cancelled on 22 February 1940. The "G specification" never "evolved since you have to have a start for evolution to begin. The Medium Tank M3 was a real tank that really existed and evolved.
Yeah seriously. I was and am not proposing French automotive development administration was superior. Not sure how you saw that in my statements. They still had a better concept than the M3, earlier, and developed further along in 1939. Neither does any of that negate the existing S35 or H40 being better to the M2 in 1939.
I was not talking about automotive developmental superiority, I was talking about the simple fact the G1 series was pie in the sky.
Likely the managers would have overlooked advantages hypothetical or real. Not invented here often stands in the way. I've searched around a bit for any transferes resulting from all the aircraft the French ordered from the US. While they directed a lot of modifications to the M167 & DB7 for French use its not clear what any US design engineers took from that. The US did adopt some British items like the 6lbr AT gun, or modifiy the 4.7" cannon to fire 4.5" Brit made ammunition, and adapt the Merlin engine, and adapt a number of Brit ship and boat designs for production in the US, and the proximity fuze, and the V1 design from Germany... I could go on with a very long list but wi/out knowing the details of French tank engineering vs US I can only ask the question.
Exactly which "managers" and which "advantages"? The US Army Ordnance had experimented with French-style Horstmann suspensions, vertical coils with leaf springs, and leaf springs with torsion bars. French engine technology was problematic (one of the many root problems with the G1R was Renault wanted to keep the standard 180 HP engine of the CharB1 in it) with nothing for the US to gain from. Gun technology? The SA37 47mm gun was nice, but outclassed by the British 6-pdr and the American 75mm.
BTW, the US did not "adapt" the British 4.5" Gun ammunition to the American 4.7", since the 4.7" never went beyond pilots. US Army Ordnance took the British GUN design and adapted it to the standard US M2 155mm Howitzer Carriage.
As you note, NIH was not a big deal for US Army Ordnance. They happily accepted the 6-pdr and would likely have accepted the 17-pdr if the 76mm wasn't so much more advanced at the time (in terms of being an actual tank gun). Ditto with regards to the Merlin and various other boaty things.
The French just had little to offer.