Messerschmitt 109 Improvements

AFAIK the 109's rear fuz was built up in quite a different manner indeed, the skin lateral edges were folded and forged/forced into the interlocking J section shapes that correspond to the webs/frames of the Spirfire - the tail of the 109 ended up a monococque construction that the longerons were then it'd appear were inserted in-thorough holes in the 'webs' to finalise lock the structure, where as in the Spit, it had a structural skeleton of ribs and longerons to which the skin was then applied to.

Tante Ju said:

I still struggle to see why, perhaps you can explain and highlight the major differences in construction? To me the fuselage construction of the Me 109 and the Spitfire are quite similar. I do not see how the joining method for the two plates effects this - in the 109 the sections slided into each other, giving a smoother transition - but the shape was decided by the ribs and the longerons provided stiffness on both planes.

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The fuselage construction of a Bf 109 is totally different. There are no particular formers. The formers are part of the relevant skin segment. See link Metallflugzeugbau Metallbau Flugzeugteile spare parts Me Bf 109 - Hartmair Leichtbau Freising

As above. Thanks gentlemen. What something looks like and how it is constructed are two entirely different things.
Cheers
Steve

I still don't see your evidence stona... So again, why would it be structurally so difficult to use a smaller volume 109 fuselage past the cocpit? Separate or built in former, not having holes in the ribs and other minuscule details have absolutely nothing to do with it! Yes the British choose a rather more tedious way of building a very similar load bearing structure that presented less smooth finish but that's that. Please don't tell me that producing different sized former is actually easier than pre-fabbing sheet metal at a different angle...

Mtt apparently managed to do it for the sake of a single prototype, and I absolutely doubt that they put much energy into "totally redesigning" the fuselage or that there was any major difference. I suppose there was another reason - either yaw stability would be compromised, or, even more so, satisfactory pressurized cockpits could not be build this way! Assuming that it would extremely difficult to do something that even a minimal design crew of a mock-up could do or that it just escaped the attention of some of the brightest minds in the aviation industry is not making any sense to me.

I think that t on the radial engines prototype model, the cockpit is higher (for similar visibility over the engine, nose sides) as the radial would be taller than the inline so..., and so when the altered forward to mid fuz is smoothed into the tail fuz, that it might be for all intent purposes, a normal tail, the open canopy is resting slightly over and rearwards of where the jettisonalbe aft glazing would've been in my mind, but /I may be quite wrong.

The point is that to make a low back Bf 109 you would have to redesign every single skin-sheet (both types) that make up the fuselage monocoque behind the cockpit. All those skins are a full half fuselage profile, (at the relevant place) and have other integral structural elements built into them. The stringers pass through what engineers would call the "integral formers". The two stringers running along the joins between the two halves (top and bottom) were wider and could take two rows of rivets, effectively holding the two halves together. I think that's what the worker wedged inside the fuselage is doing above.
This is not the case for the Spitfire where the skins are riveted to an easily modified framework comprising all the structural parts attached to the frames. The low back modification is to eight frames and some skins. It is a much simpler modification to carry out mid production. It's the reason that both high and low backed versions of some Marks could be built.
The two construction methods are quite different and that of the Bf 109 does not lend itself to easy modification.
A one off prototype is hardly relevant to re-engineering the fuselage of an extant type already in full production.

Here you can see the "top hat" stringers (so called due to their cross section) passing through the formers which are part of the skin plate


Here you can see that this is not the case on a Spitfire. The stringers are riveted to the frames and the skin plates are entirely separate.



Cheers
Steve

Designing a new canopy with better vision ultimately falls back on the Bf 109's biggest shortcoming. It was just too small.

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I hate to say it, but you are right, Steve. The Bf 109 was a brilliant design and arguably the most advanced fighter in the world when it first flew, combining modern features such as landing flaps, all metal stressed skin construction, enclosed cockpit, retracting undercarriage, high lift slats etc in one airframe, as well as practicalities inherent in its design, which made it susceptible to mass production and ease of maintenance. Like many objects of its time, the Bf 109 was also suceptible to fashion, which was among single-seat fighters for a high back rear fuselage that the cockpit faired into; almost all designs of the time were the same.

The fact that enabled such high numbers of the type to be built was the basic design, but like Adler suggests, was subject as much to environment as it was because of its design. My thoughts on a low backed Bf 109 are as follows bearing this in mind; to redesign the rear fuselage in such a fashion would take up time and require new jigs on the production line and retraining of staff, all of which takes time. If such a measure was to be undertaken, would it be worth interrupting production to do this? The Bf 109 underwent many significant changes in its lifespan, but not structurally aft of the firewall. This was the secret to its success and its longevity as much as it was the aircraft's most limiting factor (its size). Besides, other than improving the pilots' view, was it entirely necessary with a better, more modern design under development and production in the Fw 190?

The reason I ask this is that toward the end of the war the Bf 109 was showing its age and design limitations and advanced fighters, both German and Allied were proving superior to it in terms of technology and performance. Besides, despite the poor view form the cockpit (I too have had the priviledge of sitting in a Bf 109 - very hard for me since I'm six foot two), German aces did not shy away from the type toward the end of the war.

Was it necessary to carry out such a modification to its basic design, taking all things into consideration? Also, since it could be done, albeit not without considerable redesign, why was it not done? Messershmitt and Co were aware of its shortcomings and its not like they didn't have the rersources to do it early on. Is it because there were better, more advanced designs waiting on the drawing board? Probably.

Well done getting into a Bf 109 at 6'2". I'm 5'9" and barely fitted. I'm also rather broad in the shoulders (think front row in amateur days!) and that was a bigger problem, I am wider than the cockpit opening meaning I was effectively hunched all the time. This also makes it almost impossible to rotate to see behind, or as much behind as is actually possible, which isn't a lot. It's definitely not for more heavily built pilots.
I don't think photographs and drawings can show just how tight it is.
Only last year I sat in a Spitfire and thought it was a bit tight, until I remembered the Bf 109
Cheers
Steve

It isn;t that tough to redesign the fuselage to cut it down for a bubble. The parts are different, to be sure, but the new parts are just Aluminum assemblies lke the old ones.

It does take some effort, but nothing extraordinary.

Messerschmitt was a private company with the goal to earn money. Of course, nearly everything could be done if there is someone who requested this and was willing to pay for it.
cimmex

Paying for the 100's/1000's of new... moulds, formers, shaping and press tools, shape checking gauges, and the collection and redistribution of old and new such items to the production untis, factories, workshops and sheds etc. And that's assuming the prototyped new tail fuz section passed trials.
Achieving all the same strengths and good attributes as the old design, while bringing other extra benefits to the overall package as well as natural affect of the new desing, reduced material wastage, slightly less structural weight for no-less or more structural strength, improved or same aerodynamical figures etc The sectional halves would at least all need reshaping/new compound radii so they couldn't be used to repair 'early design sections' as they wouldn't match.

If that could be done, I'd say the cut down wouldn't be as much as the Spitfire or Mustang or Thunderbolt, perhaps a tapering/progressive cutdown to handle the flight structural loadings. where there is more lost at the cockpit end and almost none by the tail attatchment end - perhaps a fin fillet would be ahhed later around the equivalent of the late smoother G10-AS...

Guesstimating say 10cm height reduction at the cockpit and 2cm at the other tail end with the contours redone and the pilots/started-handle locker also having to be reduced reshaped to merge the 'new' tail fuz. The merging of the cockpit glazing/perspex towards the rear might look a little Yak like in the rear aero glazing, perhaps a Earla canopy if this was happening semi late war?

GregP said:

It isn;t that tough to redesign the fuselage to cut it down for a bubble. The parts are different, to be sure, but the new parts are just Aluminum assemblies lke the old ones.

It does take some effort, but nothing extraordinary.

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Of course it could be done. The problem is that unlike most other types, and due to the way the fuselage is constructed it involves re-engineering 100% of the structure behind the cockpit. That's been my point all along.
It would be an expensive and time consuming exercise. It cost Messerschmitt AG 38,000,000 RM to sort out the Me 210, not the RLM. It cost Messerschmitt his job. It also cost considerable production of the Bf 109 for reasons I don't have time to type here. Suffice to say that between October and December 1941, just as production was switching from the E to the F not one Bf 109 left the Regensburg assembly lines.
I don't think that the Ministry had a great deal of confidence in the company mid war. Just about all they needed was another fiasco involving one of the two single engine fighters they had which actually worked.
Cheers
Steve

Germany had some advantages and some disadvantages with 109 production I believe. I am not a 109 expert so would welcome correction on this.

How many factories or plants built 109s?

If you are going to do something like the cut down fuselage do ALL plants/factories get the new tooling or just some and some 109s keep getting built with the high back?

I believe that NA had just two factories building P-51s ( could be wrong and I don't know how the sub-contractors fit into it)

Many Allied fighters came from 2 or 3 factories, granted they may have been larger than the German factories and may have required more tooling per factory.

Anyway, just an Idea I am throwing out.

Shortround6 said:

How many factories or plants built 109s?

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If we're talking about a realistic time frame for this modification we are probably talking mid G production. By early 1943, around the time that the G-6 started arriving at operational units, the Bf 109 was essentially coming out of three plants, Regensburg, Erla and Wiener Neustadt. A few were licence built at Gyor in Hungary.

If a low backed version was shown to be viable I would expect that initial production of the type would come from Regensburg as this seems to have been the way the company operated, followed by the others. Whatever happens production will be lost, and that's assuming there is no repeat of the numerous fiascos that dogged the production of various Messerschmitt types throughout the war.

Cheers
Steve

stona said:

Of course it could be done. The problem is that unlike most other types, and due to the way the fuselage is constructed it involves re-engineering 100% of the structure behind the cockpit. That's been my point all along. It would be an expensive and time consuming exercise.

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You make a lot about it. The original Bf 109 was designed in about six months from scratch, using the previous Bf 108 experience as a rough basis. In twelve months the prototype was ready. That puts into perspective how much design work would be needed to reshape a couple of very simple structural element. Another example - the 109K for example incorporated over 1500 minor changes in construction, some effecting the fuselage (rearranging access doors and internal equipment, so somewhat similar components are effected). Again the design work from proto lasted about six months.

The Germans (and I am sure pretty much everybody else) used general machining tools - cutting sheet aluminium to size, bending them to shape etc. - otherwise resetting production would have taken a lot more than it actually did, and would be largely impractical to invest in, given that most companies produced a good number of aircraft types, not just one. These would need to be re-set but its hardly big issue either. Even small sub contractors built parts.

I believe there were three major factories in the mid/late war engaged in Bf 109 production/assembly, these would be Messerschmitts Regensburg plant (Bavaria), Erla (in Leipzig, Saxony) and WNF in Austria (the latter was pretty much the equivalent of Castle Bromwhich, being a large, automatized state owned factory, and probably more demading to set up, as it also had conveyor line production).

BTW thank you for your description, very good indeed. But I failto see what makes to design fundamentally different - construction method was, sure. the formers did not just grow onto the skin of the fuselage on the 109, I assume it was simply designed that way because it was probably easier to bend an aluminium plate to form the skin, and then attach the former to it on a bench, and then assemble (rivet) the whole thing together from two halfs than trying to do a lot of riveting inside the fuselage in very restricted space. But the components are essentially the same, the assembly sequence is different. There is simply no reason as to assume one is more easily modified than the other. You still need to produce a new set of nearly identical components (which doesnt strike me as terribly demanding, especially looking at how much simpler the 109 former is - a simple bent shape instead of of tediously holed one).

The Bf 109 (and other Messerschmitt fuselages) were built that way because it was a very efficient production system. The entire Bf 109 design was sympathetic to the rigours of series production.
Whether you like it or not, to make a low back Bf 109 you have to re-engineer the entire fuselage behind the cockpit. Every single skin plate and integral former will have to be redesigned and re-tooled on the production line. This was never done throughout the entire series production, right up to the K, and there is a reason for that.
Cheers
Steve

stona said:

Whether you like it or not, to make a low back Bf 109 you have to re-engineer the entire fuselage behind the cockpit. Every single skin plate and integral former will have to be redesigned and re-tooled on the production line.

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Right, just like on any other plane, including the Spitfire. You can't get around it, you need to design (not too terrific task) and produce new components for the fuselage. It may cause some production loss, and the RLM just like the British Air Ministry decided it just does not worth the fuss. Only a handful of low back Spitfires ever saw service at the end of the war, and there's a reason for that, even though the RAF was anything but hard-pressed in 1944.

those cockpits werent designed for 30 year old or 40+ year old men. the guys that flew them were late teens...early 20s for the most part. if i tried to slide into the cockpit of any of them now it would be a way tighter fit than it would have been 37 years ago when i was 20. back then i weighed a buck 35 with wet hair. you look at pictures ( from both sides ) most of the pilots are fit and trim. and those cockpits were still large enough for the occasional romantic moment with a fraulein....

you need to design (not too terrific task) and produce new components for the fuselage.

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You also need to compensate for the reduced surface area of the fuselage by increasing the size of the fin/rudder assembly - as it was, the Bf 109's fin/rudder was very small.

I'm still not convinced by the need to do this at all, to be honest. Yes, the pilot would have a better view, but as I stated earlier, the Bf 109 was a product of its time and had the war not intervened would probably have been replaced by something more advanced, like a jet fighter, rather than the extent of the modifications that were actually carried out on it. The requirement for a single-seat turbojet fighter was issued to Messerschmitt/BFW in January 1939, with the P 1065 design appearing on paper in October of that year. At that time, the future of the Bf 109 was to be different to what it became in the eyes of its designers. This is because the war brought about many of the modifications incorporated into the design and arguably led to its longevity. Besides, the Fw 190 proved a better fighter, despite everything done to improve the 109.

bobbysocks said:

those cockpits werent designed for 30 year old or 40+ year old men. the guys that flew them were late teens...early 20s for the most part. if i tried to slide into the cockpit of any of them now it would be a way tighter fit than it would have been 37 years ago when i was 20. back then i weighed a buck 35 with wet hair. you look at pictures ( from both sides ) most of the pilots are fit and trim. and those cockpits were still large enough for the occasional romantic moment with a fraulein....

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Also remember people in general were a lot shorter (and thinner) in the late 1930s than today.