That may be, but even pre-war, rather lightly built proto Bf 109s had a documented break-point of 10,8 G, and I recall some intrumented test from mid-war which achieved somewhere around 13 or 14G without breakage. IIRC that was on a Bf 109G.
13 G doesn't sound at all unreasonable as an ultimate load factor for a well built WW2 SE fighter. Max 12 Gs were quite typical. 'Safe' limits, with lots of safety built in was around 6-7 G for the aiframe. The safe limit was usually ~6.5 G for mid-war 109s, when fully loaded.
Actually I agree that an ultimate load factor would be 1.5 over design limit based on conventional design criteria.. I would also believe 10.8 G for a 109 as a documented stress to ultimate test. I would be very interested in seeing 13 G but even believe it 'possible' but would still like to see the tests.
The 51 passed Navy Carrier landing tests for 'drop' landing in WWII but I am unsure what that standard was in 1944...the Drop Tests and arresting gear loads were always the limit loads to wing and fuselage longeron/beam design criteria for navy fighters.. but that is a different case altogether for lift loads at high speeds (as in dive) and lift loads in a high G turn.
The 51 did have a design issue with the main wheel cover, 'unlatching' in a dive cause the landing gear to pop out resulting in catastrophic failure - but that had nothing to do with a 'fantasy 7 g' limit proposed by Soren... and it was fixed with uplock kits in the B model, permanent design feature in D and H (and P-82)
The 51 had the main spar at center of Lift Kurfurst, and it had a secondary torsion box created by the spar at the flap interface, undisturbed by wheel well or anything else. out to center of lift.
The 109 wing had the main spar aft of Center of lift and it's 'torsion box' created by the flap spar was certainly useful but the one created by leading edge spar was essentially useless for positive vertical bending loads - because of the big 'ol wheel well cutting away all the shear web capability - at the worst possible spot. Meaning the center of the lift, forward of the Main spar was taken out in torsion in contrast to simple bending.
I didn't design the 109 so I don't know the final rationale but it is clear that it has one huge design flaw - the landing gear in context of difficulty in landing- was designed that way to minimize spar size and wing weight.
The gear attach is close to the fuselage so that it could take much of the positive langing loads at the root/fuse area rather than outboard spar.
The 51 and 47 on the other hand had to be designed to carry a LOT of weight out around midpoint of spar (landing loads w/bombs or ferry tanks, and full internal fuel plus guns and ammo) - by necessity a deeper and more fundamentally heavy spar.
So Soren blurts out nonsense when he proclaims that a 109 has 2x design limit load capability over a 51.
Look at all the foolishness Messerschmitt had to go to just to increase firepower - or range. He didn't put internal wing cannon in either the F or the G wings, nor did he hang fuel tanks or bombs from the wing.. there was a reason for that.
If Heinz Nowarra's accounts of the early 109F failing in high G turns is incorrect - I would like to see the rebuttal to improve my own understanding.
Regards,
Bill