BF109G-4 "Red 7" Destroyed

[Springer6]

I'm sure that you are absolutely correct about the negative camber of the wheels giving rise to the ground stability problems.It seems obvious now that you have pointed it out.

The reason the designers gave it this camber was obviously to keep the vertical chord of these large diameter wheels in line with the undercarriage legs,so that when the gear was retracted into the wing it would present the smallest possible depth within the wing.
( I am not clever enough to attach an illustration, but I'm sure you know what I mean).

This would also account for the wheels/tyres  having to be so narrow.

If you look at a cutaway drawing of the 109 wing, the gear is towards the front edge, forward of the main spar and when retracted the tyres are sitting not too far from the leading edge at a shallow part of the already thin wing. Trouble is there isn't anywhere else in a 109 wing for the undercarriage to go.

I think that to change the basic undercarriage design would probably have required a complete re-design of the wing, something that could not be contemplated in German wartime industry.

By contrast in the Spitfire (also with a shallow wing, but of greater area than the 109 ) the chassis ,whilst still hinged at the fuselage end ,retracts into the thickest part of the wing , behind the main spar. This allowed Supermarine designers to give  the wheels a positive camber and fatter tyres albeit on smaller wheels.

Willie Messerschmitt must have been aware of the problem from an early stage, because in the bf 108 Taifun with a similar basic chassis to the 109 (but  hinged at the wing root rather than the fuselage) he was able to give the wheels a slight positive camber because of the thicker profile wing.
The proposed 109 replacement the 209II had a wide track  inwardly folding chassis with positve camber wheels ( like the FW190 and the Hurricane)

[C]

As always I suppose it was a trade off between practicality and performance, the best example being I suppose a direct comparison between the Hurri which was more practical (and conventional) in design and handling characteristics (for a trained Sqn pilot) and the Spit/Bf109, which really pushed the high performance design philosophy and technology of the mid 1930s (if only they'd had fuel injection in the Merlin).

I suppose the other problem with mounting the 109s undercarriage in a similar fashion to the Hurri would have been the track - without disturbing the fuselage monocoque you'd be looking at a track of around 12-15ft, which would certainly made ground handling interesting to the other extreme...

[Hagar]

I'm sure you're correct Springer. It also occurred to me that it would have a marked toe-out angle with the tail down. This would make it difficult to steer & explain Mark Hanna's comments on unpredictable behaviour after landing.

Once down on three points the aircraft tends to stay down - but this is when you have to be careful. The forward view has gone to hell and you cannot afford to let any sort of swing develop. The problem is that the initial detection is more difficult. The aeroplane is completely unpredictable and can diverge in either direction. There never seems to be any pattern to this.

Also interesting to note that the 109 had no adjustable rudder trim. They seem to have relied on the brakes for steering & to get the tail up on take-off. Do that in a similar fighter & you would stand it on its nose.

[Hagar]

I suppose the other problem with mounting the 109s undercarriage in a similar fashion to the Hurri would have been the track - without disturbing the fuselage monocoque you'd be looking at a track of around 12-15ft, which would certainly made ground handling interesting to the other extreme...

The Germans are famous for their ingenuity & brilliant engineering. I'm sure they could have come up with a practical solution if they'd put their minds to it. No need for any radical design changes as that would have upset the whole production technique. That was the main advantage of having those main legs attached to the fuselage instead of the wings. Giving the main wheels a positive camber angle would have made it into a pussy cat, I'm certain of it. I wouldn't mind betting that my late father-in-law would have solved it. That's the sort of challenge he relished.

[Springer6]

Hagar ,

One possible solution for the 109 might have been to reduce wheel diameter ( possibly lengthening u/c legs slightly to maintain prop ground clearance) and to apply a positive wheel camber. Wing bulges could then accomodate the tips of the wheels in much the same manner as the earlier Spits. I don't think that the aerodynamic penalties of such a mod would have been too great.

We forget though that this was war and so what if you lost a few pilots and machines in landing accidents, the disruption to production of major u/c mods would have been worse.

The Brits for example continued to use the Seafire for carrier work for lack of anything better even though the Supermarine fighter was not  really strong enough for the job. They nosed in so many aircraft on carriers at Salerno due to a lack of headwinds that they had to resort to sawing 6 inches off the prop tips to keep aircraft in service.

[Hagar]

I could of course be talking a complete load of nonsense.

Check this out. http://www.virtualpilots.fi/feature/articles/109myths/
Interesting to note the various methods used for take-off. Some pilots opened the throttle slowly while others gave it full power straight away.