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blakduk
10-04-2006, 10:16 PM
Does anyone know why the Bf109 went through a period of having a retractable tailwheel (the 'F' series), only to have the G6 model reintroduce the fixed one, followed by the 'K' series return once more to a retractable one?
I would have thought the reduced drag would have made it worthwhile, especially as they seemed to have solved the technical difficulties in the earlier models.

blakduk
10-04-2006, 10:16 PM
Does anyone know why the Bf109 went through a period of having a retractable tailwheel (the 'F' series), only to have the G6 model reintroduce the fixed one, followed by the 'K' series return once more to a retractable one?
I would have thought the reduced drag would have made it worthwhile, especially as they seemed to have solved the technical difficulties in the earlier models.

Targ
10-04-2006, 10:18 PM
Just a guess but maybe production and cost issues as the retracable tail wheel might have created logistical problesm. The G-2 had one as well.

Sordid_Sinister
10-04-2006, 10:28 PM
I'm no expert on this, but as far as I know the G6 was basically a lightweight version of G5 without cockpit pressurization, etc. Perhaps they switched to a fixed tailwheel on this version too.

flakwagen
10-05-2006, 06:03 AM
I think some pilots disliked them because they thought they were mechanically unreliable and didn't offer enough of an aerodynaic benefit to be worth the trouble of having. But I don't remember where I read this. I think it was a pilot interview transcript.

Flak

ploughman
10-05-2006, 06:12 AM
I've wondered about this.

So what's the story?

Low_Flyer_MkVb
10-05-2006, 06:34 AM
The story? I'll give you a story. O.K. Let's see... The Lufties would have you believe some stuff about cost-effectiveness and so on...truth is the springs needed were all had away by non other than H. Goering who needed vast amouts of high tensile coiled steel to upholster his vast butt on the seating of his personal Merc when his farmers were playing up. They got some bumpy roads over there you know...anyway, as so often in times of war, all this preparation came to nothing when he decided top go by train instead. This decision had a disasterous effect on the German buffet trade - but that's another story...

Ratsack
10-05-2006, 06:36 AM
The tail wheel remained semi-retractable up to the G-1 / G-2 series. Thereafter, larger wheels were introduced because the plane needed to carry heavier loads from poor forward airfields. The new, larger main wheels required the bump you see on the main planes of all Gustavs after the G-2. The bump provided the room for the larger tyres to be retracted into the wing.

The new, larger tail wheel introduced at the same time was too big to retract. It was fixed in the down position, and the wheel well was usually covered with a dust cover.

The Bf 109 kept this general arrangement until the K series made the tail wheel fully retractable for the first time.

Cheers,
Ratsack

luftluuver
10-05-2006, 07:11 AM
There was also the lengthened tail strut which left the wheel exposed (some G-6s & G-14s, plus G-10). The long strut helped fix the ground looping problem.

The K-4 with the long strut was retractable and used clamshell doors, but the K-4 could also be found with the short non-retractable tail strut.

The G-10 was a real dog's breakfast with different combos of main wheels, tail wheels and tails.

Also remember reading someplace that there was a problem with retracting the tail wheel so it was locked down.

Kurfurst__
10-05-2006, 03:11 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ploughman:
I've wondered about this.

So what's the story? </div></BLOCKQUOTE>

As RS told, a larger tyre size was introduced during the early 109G production, and it would not fit into the tailwheel bay, so it was locked down as a fixed one. It cost some 10-12 kph in speed. I believe from manual this was introduced around early 1943 in service, and it effected all 109Gs which had the enlarged tailwheel tyre.

So it was intended retractable on the Emil, was retractable on Friedrich and on the 109G up to early 1943, then not retractable again until the 109K in the end of 1944.

A curious thing about the 109G that if you look at the main wheel bays it's different from the 109F - which was all rounded as opposed to the Gustavs straight section towards the outside. This was because originally the 109G was planned with those main wheel well covers that only came into production - save a few odd 109Gs - with the 109K. AFAIK Mtt overcomplicated it's mechanism a bit with the 109G..

StG2_Schlachter
10-05-2006, 05:10 PM
Why did Messerschmitt not simply adapt the size of the wheel well to fit the larger tail wheel?

It's just a matter of cutting a larger hole into the rear fuselage, no? http://forums.ubi.com/images/smilies/blink.gif

Ratsack
10-05-2006, 07:41 PM
I don€t know why, but I can speculate.

The tail end of the 109€s fuselage where the wheel was located was very thin or narrow. We can assume there were major structural members in that immediate vicinity, supporting the fin, rudder and stabilizers. On the basis of these two premises, I infer that cutting away at anything in that region would entail modifying main structural members of the fuselage.

This is not a trivial exercise.

To do it systematically would mean they€d have to modify the welding jigs for the fuselage on the production line. Every jig. This was an incredibly time-consuming and labour-intensive process in the 1940s, and they probably decided it wasn€t worth the cost and delay. This seems more likely when we consider they would€ve been making this decision in early 1943, when the crisis at Stalingrad finally forced the Nazis to fully mobilize their war economy (two years too late, thank goodness). Delays to production would€ve been anathema at that point, and the 109 probably suffered.

Kurfurst would know more, but I seem to recall that the Bf 109 G-6 was the first fruits of the German aero industry€s attempts to boost production in the post-Stalingrad era. From memory (and I€m happy to be corrected here), the concept was to take the existing G-2/4 airframe, improve it as much as possible without causing production delays. The idea was to make it as good as they could straight away, and rush it into production as the first of a series of stop gaps. They then used the result - the G-6 - as the basis for incremental improvements, as new equipment became available. This gave rise to 1.42 ATA boost in Sep 43, then the U4 with the MK108, then the DB605AS engine, then MW50, etc, etc, etc.

The Brits most certainly made similar sorts of decisions with the Spit and Tempest, balancing the need for technical quality against strategic requirements to maintain their force at sufficient strength. The Germans were operating under the same constraints. The only people largely free of these problems were the Yanks, and even they used modification centers rather than interrupt production.

That€s my guess, informed or otherwise.

Cheers,
Ratsack