DVL data on Bf 109 roll rates

[OttoJ]

Originally posted by Squire
Mig-29, F-16, Tornado.

They all use different styles and designs, and all work just fine too.

British cars have the steering wheel on the right side, doesnt mean they are inferior. Just different.

Yes they are inferior!

[gripen]

Originally posted by Knegel

You be right that the 109F got heavy stickforces at high IAS, thats one reason why it was a very good high alt fighter.

Actually DVL planned to test this plane also at 6 km, but:

"Die messungen in 6 km Höhe konnten jedoch nicht mehr durchgeführt werden, da der Versuchsträger infolge Feindeinwirkung vernichtet wurde."

BTW please check the charts Abb. 11 and Abb. 4 and correct your chart.

gripen

[Angus]

I seem to recall that at some alt it was troublesome to push the 109 into a blackout condition at all. That would more likely have to be high alt yes?
Anyway"As you pointed out, and as you can see in the document above, the Spitfire wasnt better(regarding rolling) than the Bf109F at combat speeds, therefor i guess the clippled wing spit was not only needed vs the FW190, specialy the SpitV did suffer speedproblems, so i guess every advantage was welcome.
Since most planes had enough power to make the blackout, in big degrees, to the turnlimit, the rollratio is the most important axe while evading a attack and while following a evading enemy. "

It's new news that the Spitfire clipping occured to counter the uber-rollrate of the 109. Wonder what the 190 guys say about that.
And for the rollrate factor, - try it in AH

[Knegel]

Hi,

Gripen, you be right, curves adjusted!

Angus,

in every alt it was troublesome to push any WWII fighter into a blackout, if the speed was low.

I dont know any WWII fighter which had a limited sustained turn due to a blackout, but from 1941 onward the pilots in general did avoid to make close slow turnfights(somewhere i did read that 80% of all planes got shot down by a suprise attack anyway).

I dont told that they clipped the wings cause the 109, i wrote it was helpfull, specialy for the relative slow SpitV´s also vs the 109´s.
In low and medium alt the CW Spit still could turn good enough, so why should they keep the wingtips? Good pilots didnt need the smooth stall, but a much better rollratio and more speed is always welcome.

btw, only you talk about a uber-rollrate of the 109.
 
Greetings, Knegel

[Grits]

Originally posted by Squire
...the Tornado uses the same style of yoke, where only the top portion rotates for bank. So it is still used.

The A-4 Skyhawk used that type of stick too.

[Angus]

I seem to recall that the Hurri II could sustain a constant 5G
Later model Spits could sustain  6 or 7.
Found it in an audobiography, there was a chapter about G suits.
I'll look it up.

[OttoJ]

That's just BS Angus. No prop-fighter has enough power to sustain such G loads. 3-4 G's max.

[Angus]

Dug it up
The Hurry COULDN'T sustain 5G's long enough to make the G suit a practical thing. So, shame on me.
The later spits could  keep enough to put you asleep (that's 5 g's for 5 secs as measured in a centrifuge, RAF test 1940's), but not much longer.
However the use of the suits in a Spit VIII unit were cancelled, for it meant extra 4-5 minutes for scramble, which was a cost of some 20.000 feet.
Climb for the aircraft (initial I presume) is quoted as 5000 fpm, and top speed 420 mph, so when on ready, too much was found to be lost by the bulky suits.
But they were tested and worked quite well.
The LW tested some suits as well I think. In 262's??
I recall Rall mentioning that blackouts were not a problem, - sometimes he would black out, but not enough to lose conciousness. Mostly it was tunnel vision.
The G suit issue is however on a tougher scale, - when your blood start pooling and eventually you faint.

[Kurfürst]

Originally posted by gripen
At 400 mph IAS and with 50 lbs stick force, the Bf 109 had the lowest roll rate if compared to other planes in the NACA chart ie the forces were very high.

Quite silly way of expressing your hatred to the 109.

First, 'the stick forces were very high at 400mph' - of course. So were on every other plane appearantly. You told nothing, effectively.

Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it.

Third, factually you are wrong about the lowest roll rates, for appearantly there`s not much difference in high speed roll between the 109 and Spit,  F4F, F6F, P-39, and its much better than the Typhoon or Zero.

The Spitfire (metal a.) for example, required well over 75 lbs/~35kg to deflect the ailerons sufficiently to develop as slow roll rate as 45 deg/sec according the British tests. Above 40 lbs was required to deflect them fully up to 140 mph only.

Finally, it`s hardly makes sense to come up with extreme speeds  and make comparisons at like 400mph IAS, something like 750 kph TAS, that was near or above the Vne of most of these planes, and wouldn`t even be reached at 3000m in full powered level flights - doesn`t makes sense unless one who hates a plane wants to pick one plane, put it under extreme conditions and say it`s BAD BAD, when in fact at all practical combat speeds, the roll rate and stickforces were entirely satisfactory.

[Angus]

Ahhh:
"Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it"

Well, I thought it did. In some way. So, - that's why some designers geared the ailerons through the stick, just like lifting a stone with a long plank.

[Krusty]

Not to get into the argument and all about which plane rolled better, but you can't compare RAF ww2 stick controls to that of the tornado IDS or the mig21 or the a4 skyhawk or anything.

In ww2 they didn't have hydraulics or fly by wire electronic servos controlling the surfaces. In ww2 it was direct force on the surface, so it's a totally different ballpark. Can't compare it to modern iterations of the same type of stick.

[Angus]

That's why you'd use gearing, - i.e. more stick travel for an equal deflection like on the Curtiss for example, right?

[Krusty]

I'm of that impression, yes, but I'm going to stay out of it

I was just pointing out the wrong way of comparing things some people have

[Crumpp]

I have not read through this whole thread but I can say that RAE 1231 was a measured flight test.

The instrumentation and data acquisition is explained in the report.  This data is then used to compare with various calculations.

Calculations were done to compare with the ADM standard measurements.  The measured results were also compared to gun camera footage.

Calculations were also done to find the loss of rate from wing torsion based of the measured results.

It is easily provable by cross-referencing the aileron adjustment regulations of the FW190 series with the report that the aircraft tested suffered from out of ailerons in need of adjusting and does not represent the top rolling ability of the series.

they would be curved if it was an actual measurement and showing the elastacy effect of the wing and linkage

Generally speaking a "curved" graph of roll rate only shows the ailerons were not at full deflection.  Usually this is due to stick forces being too high for the pilot to achieve full deflection.

In the case of the NACA test's this would mean that full deflection was possible only with a force above 50lbs.



All the best,

Crumpp

[gripen]

Originally posted by Kurfürst
Quite silly way of expressing your hatred to the 109.

I wonder what do you mean? The Bf 109 was one of the most important types of the FAF and I have been collecting data on it for years because I'm honestly interested about the type.

If you don't like the data I have dug out and presented here or my postings overall, just ignore me.

Originally posted by Kurfürst
First, 'the stick forces were very high at 400mph' - of course. So were on every other plane appearantly. You told nothing, effectively.

At 400 mph IAS, the Bf 109 had lower rate of roll at given stick force (50 lbs) than all other planes in the NACA chart. See Mr. Knegel's presentation.

Originally posted by Kurfürst
Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it.

The DVL and NACA graphs show roll rate at given stick force and these include wing and linkage elasticity. Basicly all factors are included because all these are based on flight tested data.

Originally posted by Kurfürst
Third, factually you are wrong about the lowest roll rates, for appearantly there`s not much difference in high speed roll between the 109 and Spit,  F4F, F6F, P-39, and its much better than the Typhoon or Zero.

As noted above, at 400 mph IAS all these planes had better rate of roll with 50 lbs stick force than Bf 109. Again, see Mr. Knegel's presentation.

Originally posted by Kurfürst
Finally, it`s hardly makes sense to come up with extreme speeds  and make comparisons at like 400mph IAS, something like 750 kph TAS, that was near or above the Vne of most of these planes, and wouldn`t even be reached at 3000m in full powered level flights - doesn`t makes sense unless one who hates a plane wants to pick one plane, put it under extreme conditions and say it`s BAD BAD, when in fact at all practical combat speeds, the roll rate and stickforces were entirely satisfactory.

The red line speed for the Bf 109 at 3000m was 750 km/h IAS and 400mph IAS is only about 650 km/h IAS so 400 mph IAS is well within normal flight envelope and easily reachable in diving maneuvers.

gripen