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Author Topic: The enigma of the Bf-109  (Read 9697 times)

Offline MiloMorai

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The enigma of the Bf-109
« Reply #30 on: February 11, 2005, 12:30:54 PM »
Quote
Originally posted by hogenbor
Yes they did, no idea what happened to them though.


A He112B of 5*68 damaged a P-38 of the 14th GF 12 Af over Spanish Morocco on March 3 1943 forcing it down on the shore of the Mulluya R.

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Offline HoHun

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The enigma of the Bf-109
« Reply #31 on: February 11, 2005, 01:19:26 PM »
Hi Guppy,

>It still comes down to folks not looking at the overall then doesn't it.

Certainly! A careful reader won't fall into that trap - I think that's what must have happened to you :-)

The performance differences in capability between the Spitfire and the Me 109 become even smaller if you consider that they were mostly engine-determined, by the way.

One Spanish Me 109 batch was produced with Merlin engines, and some Spitfires were actually converted to Daimler-Benz powerplants during WW2, so if the two companies would somehow switched sides, the resulting aircraft would have resembled their historical opponents even more :-)

Regards,

Henning (HoHun)
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Offline Angus

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The enigma of the Bf-109
« Reply #32 on: February 11, 2005, 06:19:34 PM »
This, - from Guppy:
"What other operational fighter design from the mid 30s was still a front line combat aircraft in 45?

Dan/Slack"

Well, the Spitfire, of course ;)
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It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline MANDO

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The enigma of the Bf-109
« Reply #33 on: February 12, 2005, 04:01:15 AM »
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Offline Charge

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The enigma of the Bf-109
« Reply #34 on: February 13, 2005, 05:35:37 AM »
Interesting: "As would be expected the 112 had better turn performance due to it's larger wing, but the 109 was faster at all altitudes and had considerably better agility and aerobatic abilities."

"In addition some sources have mentioned that the 112 continued to suffer from lateral instability throughout the test period, which caused the plane to "snake" in flight. The various modifications to the vertical stabilizer may be evidence for this problem."

I guess Heinkel didn't notice that the fuselage should be tall and slender as in Spitfire to counter the effects of elliptic wing...

-C+

To Angus: Air resistance in the subsonic region, in which from now on the wing-only airplane is to be seen, was clarified by two messages in the Lifting Wing Theory by L Prandtl (published 1918). The diverted induced resistance becomes a minimum, if the lift is distributed over the span in the form of a half ellipse, in the case of a given span and a constant weight of the airplane. If now the wing has the form of an ellipse, then (without washout) the lift coefficient is same in every place of the span. Close to the max. lift a local flow separation can bring a rolling moment around the longitudinal axis of the airplane, which the pilot can barely adjust with the aileron, because the whole wing is close to the max. lift. The elliptical wing was therefore sparsely used for reasons of the flight characteristics and production.

http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/theory/theory.html
« Last Edit: February 14, 2005, 05:51:30 AM by Charge »
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Offline Angus

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The enigma of the Bf-109
« Reply #35 on: February 13, 2005, 10:19:28 AM »
What are the effects of an elliptic wing?
AFAIK it's maximum lift with the minimun lift-induced drag penalty.

BTW, a powered-up speedy spitfire already showed the tendency to "crab" sideways in full power flight. Later model Spits had to enlarge the stabilizers to counter the torque.

The 109. AFAIK, needed a constant boot on the rudder.
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It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline Kurfürst

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The enigma of the Bf-109
« Reply #36 on: February 14, 2005, 05:35:18 AM »
Early Spits imho had this problem of directional stability because of their assymetric radiators.

As for the 109, there were ground adjustable trim tabs to trim the rudder for cruise speeds, plus the vertical fin was assymetric, countering the torque at all speeds. So when flown at cruise speeds, the plane could be flown 'legs off' like any other correctly trimmed plane.

BTW.. the 190 didnt have rudder trim either, but I never see this ebing brought up ever.
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Offline justin_g

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The enigma of the Bf-109
« Reply #37 on: February 14, 2005, 05:45:45 AM »
Quote
Originally posted by Rob Cashman
A few years later again Heinkel had the HE-280 development going very well and was much further along than the ME-262 but it did not get far.


Around March 1943 the Heinkel test pilots discovered that the He 280 tailplane would begin a dangerous "see-saw" motion at high speed which twisted the rear fuselage - which required a re-design of the entire tail unit. The time they lost fixing this problem allowed the development of the Me 262 to overtake the Heinkel effort, and the He 280 program was cancelled.
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Offline Naudet

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The enigma of the Bf-109
« Reply #38 on: February 14, 2005, 06:14:05 AM »
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As for the 109, there were ground adjustable trim tabs to trim the rudder for cruise speeds, plus the vertical fin was assymetric, countering the torque at all speeds. So when flown at cruise speeds, the plane could be flown 'legs off' like any other correctly trimmed plane.


But it is also true that with increasing speed the 109 required a lot of rudder to fly straight.
Mark Hanna also told that the rudder in the 109 though very controlable would not allow the plane to fly "legs off" at any time.


Quote
BTW.. the 190 didnt have rudder trim either, but I never see this ebing brought up ever.


Why should it? Comparing to other planes of the time the FW190 had the neat feature that it didnt require any retrimming over the entire flight envelope if the trim taps were properly ajusted.

This is mentioned in almost any FW190 test report, even by the allies ones.
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Offline Angus

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The enigma of the Bf-109
« Reply #39 on: February 14, 2005, 07:18:25 AM »
From Kurfurst:
"So when flown at cruise speeds, the plane could be flown 'legs off' like any other correctly trimmed plane. "

At only some precisely certain speed.
Plains with rudder trim can of course be trimmed to fly legs off at any speed.
Since rudder trim is not a particularly complicated thing, I wonder why they skipped it.
As for the 190, how did they solve it? Quite interesting really :)
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It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline MiloMorai

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The enigma of the Bf-109
« Reply #40 on: February 14, 2005, 07:32:06 AM »
Q. How do you tell a late war 109 pilot from any other pilot?

A. He is the one that walks with a limp because of the huge leg(single) muscles from having to continually apply rudder at high speed. (high speed was the only way they could stay reletively safe in the dangerous skies over Germany)

:p
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Offline Kurfürst

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The enigma of the Bf-109
« Reply #41 on: February 14, 2005, 04:18:26 PM »
Quote
Originally posted by Naudet
Comparing to other planes of the time the FW190 had the neat feature that it didnt require any retrimming over the entire flight envelope if the trim taps were properly ajusted.


This is surreal, Naudet. An aircraft that 'doesn`t require ANY retrimming over the entire flight envelope' - how? Why they fitted it with adjustable trim in the first place then? Some aircraft`s trim changes may be different in given axis, on some it`s more pronounced and on other it`s less pronounced, but the need for trimming is always there.

As for the 109/190.. the trimming system followed EXACTLY the same pattern on both aircraft. No aileron or rudder adjustable trim, just ground adjustable trim tabs, plus varialbe tailplane incidence with fixed trim tabs on the elevator, a rather better solution than just elevator trim on Western aircraft under compressibilty.

The bottom line of course, that any 109 or 190 could transit easily without the use of pedals. Some sideslip occured if they were not flying near preset cruise speeds - so what ?

This 'it was no problem on the 190, but on the 109, which followed the exact same layout, the same phenomenon was an extreme disadvantage' just stinks of bias.
« Last Edit: February 14, 2005, 04:22:59 PM by Kurfürst »
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Offline Angus

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The enigma of the Bf-109
« Reply #42 on: February 14, 2005, 05:34:41 PM »
Ahem.
How can the absence of cockpit adjustable trim be a benefit?

So many pilots that flew the 109 point this out as the most uncomfortable factor.
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It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline Kurfürst

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The enigma of the Bf-109
« Reply #43 on: February 14, 2005, 05:40:43 PM »
It`s ain`t a benefit, but neither an issue. Esp. not for an interceptor. Or did you mean the variable tail incidence instead of elevator trim tabs?

But name three German/Axis pilots who complained about the lack of rudder trim.
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Offline Angus

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The enigma of the Bf-109
« Reply #44 on: February 14, 2005, 05:50:58 PM »
That means you know about two?

I only know one, but I can always ask.

Anyway, think for your self, having to keep a stiff leg on the rudder to stay straight, rather than being able to trim it to leg-off at any speed you prefer.
Now Willy was a good designer, it boggles me why he skipped this one.
How about other German planes. I bet most of them had a trimmable rudder, or?

And for the FW, I do remember it being mentioned for it not being necessary to trim. I'll ask around as well, for this is quite interesting. One thing there is that control forces were really light, so maybe it was not a big issue if it was a little off, don't really know.
I do know though, from being a machine operator for thousands of hours, that needing constant muscle just to stay stable, is really really bad. But for a 1 hour mission, I guess one would get used to it, - 1 hr is not 10, and in 1 combat hours there are many worse things around.

IMHO the 109 would have benefitted from a rudder trim, find me 3 pilots that disagree :D
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It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)
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