Bf 109 F series

[Civettone]

I'm not saying that Germans had to produce Re.2005s. I'm saying that's possible to carry a bomb, or two, or even a torpedo (the Re.2005 had the same loading capability of the Re.2001/2002, that included a W125/450/3.63 600kg torpedo), under the fuselage with a ventral radiator, and incidentally it requires the same undercarriage disposition the Bf109 already had.

The G.55S would also work. Easier to produce.

That's producing it in Italy. Even producing a Bf109 in Italy would require much more hour of work than producing it in Germany. Were the industrial conditions more than the projects that made the difference.

The real problem here is that we simply do not know ! We have all read that the Fiat G.55 took 15,000 man hours to build and that it could be brought down to 9,000 through rationalisation and mass production techniques. BUT who came up with these figures? Can we really rely on them?
I believe they are estimates. I guess they were based on the technological level and modernity of the factories of Fiat and Reggiane. Fiat probably had the advantage here? I also read that the Reggiane factory was very modern. For sure, the German factories were much more advanced. Even so, I do not believe anyone in the 1930s would have thought the Bf 109 could be produced in just 2,000 manhours but that is what happened. The Fiat G.55 but also the other 5-series could probably have been produced even faster. However, this would require a lot of investments in specialized machinery and continuously training your work force. If you just invest enough, who knows where you will end up?

Kris

 

[DerAdlerIstGelandet]

Keep it civil guys...

 

[GregP]

Hi Stona,

Better landing gear geometry would have been an improvement to the Bf 109. I believe we already know the landing gear was badly implemented. It has been suggested to try fixing the geometry first ... good suggestion.

If it works go with it. If it doesn't, move the gear outward and redesign to fix it. Ergo, improvement.

Th entire intent is to fix things, whether it take slight geometry corection or majot redesign. Eliminate the faults to the maximum extent to make it better. Trying to taxi, take off, and land a Bf 109 must be like trying to drive a car that badly needs an alignment.

The redesign amount is entirely dependent on how the proposed "fixes" work. Once they work right, stop improving and move on.

Or at least that was the intent of my suggestions.

 

[stona]

Hi Stona,

Better landing gear geometry would have been an improvement to the Bf 109. I believe we already know the landing gear was badly implemented. It has been suggested to try fixing the geometry first ... good suggestion.

Agreed. Other aircraft with similar narrow track undercarriages do not seem to attract the same approbation as the Bf 109. Look at the Spitfire or even the F4F as examples. It is the geometry that is different, not simply the distance between the wheels.

Cheers

Steve

 

[tomo pauk]

I've posted this many times, a Bf-109 with small wing 'plugs' (but with cut wing tips, so the wing would be still not that big), that would've contained the additional cannons each, while the wheel struts would be aligned more vertically, without the toe-out appearance. No cowl MGs.

 

[OldSkeptic]

Agree OldSkeptic, wholeheartedly.

Thye 109F was very good. Later models could have been better but weren't.

Thanks, the size thing is key, there just wasn't enough room to cram everything in that it needed to remain competitive and maintain good aerodynamics, hence the nickname of the 'G" as the 'bulge'.
And the operational requirements had changed significantly from what was envisaged when it was originally designed.

That's why I see the "F" as the epitome of the design. And in good hands a very, very dangerous opponent.

Conceptionally (though the devil is always in the details) I don't see any major issues with the 'extended' 109 design. The longer fuselage gives you more room for fuel, MW50, NO2, etc and allows a bubble canopy. The larger wing improves high altitude performance, agility and gives more room for guns and ammo, bombs and so on. And it should be possible to clean up some other issues like the undercarriage as well, control issues and so on.

It doesn't have to be perfect by any means, just overall better than the G, basically a quick compromise upgrade like the Dora.

 

[stona]

I've posted this many times, a Bf-109 with small wing 'plugs' (but with cut wing tips, so the wing would be still not that big), that would've contained the additional cannons each, while the wheel struts would be aligned more vertically, without the toe-out appearance. No cowl MGs.

And what do the landing gear legs attach to? The attachment to the truss was to "direct the landing impact loads to a statically favourable point in the fuselage". These things are not as simple to alter as a drawing might suggest.
Is the attachment now to the main wing spar? It ran behind the wheel well IIRC. I'm not an engineer but attaching an undercarriage to a major structural component that was never designed for this might need some careful consideration. Otherwise we are back to a major redesign

I don't know whether simpler changes in geometry might have been made. As far as I can tell they were never attempted.

Cheers
Steve

 

[razor1uk]

If the main spar and the wing attatchment points had never been designed for the inclusion of landing gear, then it would require a major redesign assuming a suitable alternative redesign wasn't already waiting 'the go'.
If done in a modification of the existing structural way, then the new gears or their mountings would be much weaker than the normal ones, and then you'd severely risk loosing your wings on landings that weren't the most gradual in sink rate and on flater ground.

 

[GregP]

You know, it occurs to me that maybe I'm misunderstanding the geometry thing when it comes to the Bf 109's landing gear.

We are in the middle of repairing our Hispano Ha.1112 right now and the landing gear is one of the things that had to be fixed. When we hung the gear and tried to retract it, one leg wouldn't go into the gear well. We were a bit perplexed until we stopped and looked at the gear system. The gear attach points are bolted right to the firewall-fuselage joint. The gear projects forward from the firewall and is tied to the firewall with a turnbuckle-type brace. Simply turning the turnbuckle adjuster changes the gear geometry and it was quite simple to line up the gear with the wheel well in the end.

Since we have been talking about incorrect geometry, I surmise the issue is that when the gear is adjusted so it will retract and hit the center of the wheel well, the tires are not aligned properly for good ground handling. The solution, to me, would be to design a different wheel pivot point setup so the retraction and tracking of the wheel had separate adjustments. That is the wheel tracking should be able to be adjusted separately from the retraction plane. That way, if the tracking is indeed at fault, it could be adjusted without making the gear impossible to retract.

 

[stona]

That, Greg, is a very interesting point!
I was so focussed on the geometry that I completely ignored that the gear still had to retract into the well. Maybe that's why it was never substantially changed. Redesigning the pivot/attachment point under the pressure of war time production may have been considered impractical.
Cheers
Steve

 

[razor1uk]

Interesting info Greg, I wonder how easy it might have been to perhaps have altered/adjusted/redesigned the stub axles angle to the oleo and if that might have helped if they would've got around to it. hindsight sometimes makes things appear to simple and easy/logical than then.
It would seem that Willy once the design was final draughted for producting, he almost ignored any attempt to redress any remaining issues unless forced to by the party/command, - I suppose some of that could be because he likely understood the mass production difficulties within Germany and those vast resources manufacturing manpowers facing them.

 

[tyrodtom]

Were the wheels toed out ?
That's seems to me would be what you'd want. If you came down on one wheel, and it was toed out, it would tend to steer the aircraft outward, bringing the other wing down and the other wheel in contact with the ground, it's toe out would then cancel out the other wheel's, and the aircraft would steer straight.
I think maybe they didn't align the wheels straight because of the fear that the wheels could go into toe in, which would have the opposite effect when you got up on one wheel.
Toe in would steer the aircraft inward, making it tip ever farther.

 

[GregP]

Just for completeness, on most oleo gear, the wheel can turn on the hydraulic damper shaft and there is a strut that is fixed to the non-rotatable part of the gear lag and one that is attached to the rotatable strut as well as the rotating part. It is called a drag link. You can see it on most oleo struts as two straight link that move when the strut is compressed. You can see the drag link below:

Of course, thesea re not Bf 109 gear legs. It is just to show the drag link and the idea,

Changing the geometry would have been as simple as changing the angle of the fixed part of the drag link. Since that is NOT a major effort (landing gear are designed for all aircraft with retractable gear anyway), I fail to see why it wasn't addressed … unless the designers were not aware of the geometry issue or unless there was some reason why expending a small bit of time fixing it was simply not considered important. Or maybe Willy Messerschmitt simply refused to consider that it was wrong to start with.

 

[stona]

Were the wheels toed out ?

I think they were not toed either way. They have a rather odd geometry nonetheless.

Cheers

Steve

 

[GregP]

Most conventional gear aircraft have a small bit of toe-in. Toe-out is what casuses dangerous instability. If you land one wing low, toe-in keeps the plane going with that wing still low. If you had toe-out, the other gear would slam down without pilot control and you could easily have an out-of-control situation.

That is, of course, a general rule for which exceptions can probably be found.

I do NOT know if the Bf 109 was designed with toe-out, but will try to find out. I do NOT like the angle of the axle on the landing gear. It could have been angled so the tire was much more vertical. It probably wasn't because the wing is barely thick enough to accommodate the wheel when it is relatively flat relative to the wing when retracted. In other words, the wing probably dictated the landing gear tire angle rather than ground handling concerns.

 

[tyrodtom]

Most conventional gear aircraft have a small bit of toe-in. Toe-out is what casuses dangerous instability. If you land one wing low, toe-in keeps the plane going with that wing still low. If you had toe-out, the other gear would slam down without pilot control and you could easily have an out-of-control situation.

That is, of course, a general rule for which exceptions can probably be found.

I do NOT know if the Bf 109 was designed with toe-out, but will try to find out. I do NOT like the angle of the axle on the landing gear. It could have been angled so the tire was much more vertical. It probably wasn't because the wing is barely thick enough to accommodate the wheel when it is relatively flat relative to the wing when retracted. In other words, the wing probably dictated the landing gear tire angle rather than ground handling concerns.

If toe out would bring the other wing and wheel down, wouldn't then toe in tend to make the other wing get ever higher?

Maybe i'm overthinking it for aircraft, we use toe out in racecars to make the car turn in better, you don't want a aircraft to be easy to turn on the ground.

 

[GregP]

The toe-in we're talking about is minor. The intent is to set the toe-in so that even at maximum compression, toe-out will not develop. That is for fixed gear, spring steel legs. For oleo struts, they woiuld set slight toe-in or zero toe, depending on the designer's preference.

I am very curious about the toe for the Bf 109. but do not know where to find any information on it. Setting the gear legs so they are centered in the wheel well sets the toe on the Hispano (basically a Bf 109G from the firewall back) and also sets the gear leg so a simple sheet metal lock will engage. There are no other toe adjustments of which I am aware at this time. I can check the Hispano manual and will do so.

It simply never occurred to me to check it before. However, since it is non-adjustable, it is possible there is no spec for it in the manual. Manuals tend to give you specs on the basic airframe, torques, etc. and settings for adjustable things, not a design analysis.

 

[Juha]

True, but he was the commander of a Bf 109 unit. I am sure he knew what he was talking about...

Yes he knew but the question is what he told. Karhunen was excellent lentueenpäällikkö/Staffelkapitän, I have not an oppinion how good he was as laivueenkomentaja/Gruppenkommandeur. After retirement he was very profilient writer, he wrote probably 30+ books, mostly on the FiAF during the war. In those there were 3 infallible men, Magnusson (his immediate superior), Lorentz and himself and 2 hopeless officers, one of his collagues and the C-in-C FiAF. So ef there was some problems in his unit he didn't necessarily reveal that in his books and interviews. Even some ex FiAF officers joked on that. I don't know how it was on Bf 109G training but at least the way he told the initial career of B-239 in FiAF, and he knew that very well because he commanded the detachment which went to Sweden to accept the first B-239s to FiAF and then flew them to Finland, and how it looks after reading the official reports doesn't always meet.

Juha

 

[stona]

Not conclusive, but I've been through a couple of Bf 109 hand books and no angles for toe on the main U/C are given. They give angles for just about every other conceivable part of the airframe so I'm leaning towards a toe of big fat 0.
Cheers
Steve

 

[tomo pauk]

And what do the landing gear legs attach to? The attachment to the truss was to "direct the landing impact loads to a statically favourable point in the fuselage". These things are not as simple to alter as a drawing might suggest.
Is the attachment now to the main wing spar? It ran behind the wheel well IIRC. I'm not an engineer but attaching an undercarriage to a major structural component that was never designed for this might need some careful consideration. Otherwise we are back to a major redesign

I don't know whether simpler changes in geometry might have been made. As far as I can tell they were never attempted.

Cheers
Steve

If the main spar and the wing attatchment points had never been designed for the inclusion of landing gear, then it would require a major redesign assuming a suitable alternative redesign wasn't already waiting 'the go'.
If done in a modification of the existing structural way, then the new gears or their mountings would be much weaker than the normal ones, and then you'd severely risk loosing your wings on landings that weren't the most gradual in sink rate and on flater ground.

Fair points, people.
My proposal is less 'radical' than the Bf-109H, featuring smaller plugs and removed rounded wingtips. The 109H was featuring landing gear attached to the plugs.
File:Bf109H 3Seiten neu.jpg - Wikimedia Commons