K-4 Flettners

[HoHun]

Hi Kurfürst,

>"Seitenruder mit am Boden einstellbaren Ausgleichruder (Flettner) und geschrankten Bugelkanteln versehen.

Querruderanordung links und rechts and den Tragflachen

Beide Querruder mit Ausgleichruder (Flettner) versehen). Ausgleichruder z.Zt. festgelegt."

Ouch :-) Try to transliterate the Umlauts as follows: ä->ae, ö-> oe, ü -> ue.

>I hope HoHun can give an accurate translation, but basically: the ailerons have Flettner, but they are at present time fixed.

"Rudder features ground-adjustable balancing tab (Flettner) and trim strips with opposite bias [to avoid loss of feedback force around the rudder zero position]"

"Aileron arrangement left and right on the wings

Both ailerons feature balancing tabs (Flettner). Balancing tabs are currently fixed."

>What I remember clearly and that the ailerons could be deflected 2/3 at some very high dive speed,and that no aileron overbalance was observed with them.. 0.7Mach it was?

Radinger/Otto report overbalancing on a normal aircraft at Mach 0.79, becoming (probably) fatal at Mach 0.80. (For the latter speed, the test aircraft was rigged with 50% aileron gain to enable the pilot to keep the ailerons under control. That Me 109 was also fitted with an ejection seat! 8-O)

Regards,

Henning (HoHun)

[MiloMorai]

Did not Butch also say at one time that only ~200 of the ~1700 K-4s built had aileron Flettners fitted? Iirc correctly that was on the UBI zoo forums.

The 109K-4 handbuch also notes the aileron Flettner tabs, with the comment they are locked at the moment

So if Flettners were locked, it would seem there was some truth that Flettners made the a/c harder to control > ie precision flying like when trying to line up a target.

[gripen]

The V-tailed Bf 109 test plane was also fitted with the ailerons with geared tabs and the report contains some data on ailerons. Claimed time for one roll was 4 s with tabs and 4,5 without them, no speed claimed (with the tabs the speed was probably higher because the tabs decrease roll rate at slow speeds).

gripen

[justin_g]

It's funny how people wouldn't be as interested in this information if it wasn't for computer flight sims!:D

[Kurfürst]

Originally posted by MiloMorai
So if Flettners were locked, it would seem there was some truth that Flettners made the a/c harder to control > ie precision flying like when trying to line up a target.

I wonder how would Flettners made an aircraft harder to control, Milo. And why would be so many aircraft fitted with Flettners then : Spitfire XIV, Tempest etc.. were these also harder to control than their non-flettnered cousins?

It`s curious because all what a Flettner does is reducing stick forces, at low speeds where the controls are light anyway it shouldn`t effect much, and at high speed I wonder how can be controls so precisly with very high control forces (ie. w/o a flettner)

[justin_g]

I can only imagine that having lighter aileron forces at high speed would improve the control harmony of the 109, making it more like the 190 which had close to an ideal balance of aileron/elevator forces?

Btw; exactly how does the flettner tab work - google aint giving me nothing...

[MiloMorai]

It is understandable that you would not understand Kurfy.

Now try to see, using the following example. Early power steering on cars made steering easier but precision control of the car was harder. The driver would turn the wheel and find he put in too much. Would make a correction and find he made too much of a correction. And so on, and so on,.....

This is what pilots found with Flettner ailerons.

[justin_g]

Uhhh, how would that be any different than a 109 pilot flying a 190 first time? They just have to get used to the difference...

[Karnak]

Originally posted by MiloMorai
It is understandable that you would not understand Kurfy.

Now try to see, using the following example. Early power steering on cars made steering easier but precision control of the car was harder. The driver would turn the wheel and find he put in too much. Would make a correction and find he made too much of a correction. And so on, and so on,.....

This is what pilots found with Flettner ailerons.

Erm, that doesn't jive.  I've driven with and without power steering and have never had an issue with the transition or a lack of precision.

Unless Flettners do something really funky to the way an aircraft's control surfaces work I just can't see them adding any slop in.  Lighter stick forces make it easier to be precise as you aren't overloading your muscles.

If what you are saying is correct, then why are the Spitfire, Bf109 and A6M, all of which suffer high stick forces in some way at higher speed, so precise at lower speed?  The pilots should be mushing all over from the light stick forces at low speed, no?

[justin_g]

Hehe, got the wrong quote there methinks...

[Karnak]

Fixed it.

[hogenbor]

Originally posted by Karnak
Erm, that doesn't jive.  I've driven with and without power steering and have never had an issue with the transition or a lack of precision.

Unless Flettners do something really funky to the way an aircraft's control surfaces work I just can't see them adding any slop in.  Lighter stick forces make it easier to be precise as you aren't overloading your muscles.

If what you are saying is correct, then why are the Spitfire, Bf109 and A6M, all of which suffer high stick forces in some way at higher speed, so precise at lower speed?  The pilots should be mushing all over from the light stick forces at low speed, no?

The animosity between the two gentlemen aside, I think Milo might have a point though. I own two cars, a 1971 Opel without power steering and a 1998 Fiat with (very light) power steering. Not that I drive off the road in either one of them, but it is certainly a transition.

Is it possible that the reduced feel of the control surfaces made it more likely to enter uncontrolled flight? Or would it impose bigger stresses on the aircraft? You tell me, I'm only interested.

[MiloMorai]

I guess you never drove an early power assisted steering car Karnac. The Crysler products were the worst. Modern are much more precise.

[gripen]

Originally posted by Kurfürst
And why would be so many aircraft fitted with Flettners then : Spitfire XIV, Tempest etc.. were these also harder to control than their non-flettnered cousins?

AFAIK only one Spitfire was tested with geared tab ailerons (Flettner tabs), late Spitfires and Tempests had spring tab ailerons which are quite bit different.

gripen

[agent 009]

Ok. cool stuff. Now is there a report on the roll difference on these later Temps & Spits? At higher speeds in particular.

These can't have been that hard to manufacture, if they were a success, one would think that Willy would have ordered em on all the G-10's & K's. A puzzle it is.