DVL data on Bf 109 roll rates

[Grits]

Originally posted by 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.

Sure you can, the A-4 also had old fashioned cable backups for the hydrolic systems, so that stick had to work just like a WW2 plane if the hydrolics failed. The only reason I pointed that out about the A-4's stick was it was said that that type of control was not a good one, and some of us gave examples of other (yes newer) planes that use identical sticks.

[Krusty]

Well the stick type may be good for planes with automated controls (and A4 might have been a pig to fly on manual backups, too), but doesn't mean earlier planes were "good" as well

Regardless, "good" or "bad", they simply.. "were".

[OttoJ]

Originally posted by gripen
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.

400 mph IAS is an extremely high speed, only achievable in a dive and at that speed your only concern would be to level out.

[gripen]

Originally posted by OttoJ
400 mph IAS is an extremely high speed, only achievable in a dive and at that speed your only concern would be to level out.

Hm... as noted above 400 mph IAS (about 650 km/h IAS) is not even close normal flight limitations of the Bf 109 at 3000 m ie 750 km/h IAS.

BTW RAE had no problems to test Fw 190 Roll rate at 409 mph EAS (EAS is IAS with type specific corrections) at 10k and all other planes (Typhoon, Mustang I and Spitfire) in the same test were tested same way:



In the case of the Mustang III, RAE went even further and tested ailerons up to about 470 mph EAS at 10k:



Generally 400 mph IAS at 3000 m is not particularly high speed and easily reachable for all planes mentioned in the NACA chart.

gripen

[Kurfürst]

Originally posted by gripen
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.

Yeah Gripen, we`ve all seen your posts, you are always showing one sided stories about both the FW 190 and Bf 109, which later you can`t support with anything for even your own docs don`t support you, then you stubbornly repeat the same over and over again. Don`t fed us with BS about your honesty, please. You are hypocrite, and for some reason you hate LW planes, everyone knows it.

Originally posted by gripen
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.
...
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.

As noted to you, to which your response is only silly parrotting - how can I take your claims seriously?

Again, the FACT is the DVL doc shows 55deg/sec roll rate 375mph IAS, which is better than the Zero, Typhoon, Spitfire, P-39, F4F, and almost as good as the P-47 or F6F. As usual it is the case that gripen claims something with reference to a document, but the document doesn`t shows what gripen says it say.

Besides, it appears that Kneagel got the wrong IAS/TAS conversion got some problem, which effects the roll data very strongly, hence the margin of error is very great. You know this as well, you just being a hypocrite again.

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.[/B]

Again, you repeat the same sillyness like a parrot. I can`t take you seriously with 'arguements' like this.


If you really wish to prove the 109 had higher stickforces than others, why not posts stickforces themselves vs. other planes?

I already looked that up with the available data, and they don`t support your claim at all.

The NACA says the Spit having troubles with stickforces already at 140 mph IAS, above which full deflection is not possible.

Another Spit (metal) doc (AVIA 6/10126) shows the aircraft needs 71 lbs stickforce to deflect the ailerons only by 4.5 degree at 400 mph IAS.

Whereas your doc shows that FULL aileron deflection (avarage 15 degree, almost four times more) can be reached on the 109 with only 66 lbs stickforce up to 330 mph IAS. With a comparable 40 lbs stickforce as in the NACA`s Spit tests, the 109 can deflect ailerons fully up to about 265 mph IAS. So what are you talking about, I ask.

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 [/B]

Easily reachable? That`s merely an opinion of yours. Basically you say that at speeds that wouldn`t even be reached by 90% of all WW2 fighters at 10k ft, the roll rate of the Bf 109 is bad. Quite irrelevant really,  dogfights featuring wild barrell rolls near Vne speeds only exists in your fantasies, in fact most plane manuals strictly forbid such hard rolling manouvers at high speeds anyway.

[gripen]

Originally posted by Kurfürst
Yeah Gripen, we`ve all seen your posts, you are always showing one sided stories about both the FW 190 and Bf 109, which later you can`t support with anything for even your own docs don`t support you, then you stubbornly repeat the same over and over again. Don`t fed us with BS about your honesty, please. You are hypocrite, and for some reason you hate LW planes, everyone knows it.

 
It's not a public problem if you don't like my postings. Why don't you do just like Mr. HoHun and add me to your ignore list? And if you want to express your feelings about me even more, just add me to your signature to promote me in your every post.

Originally posted by Kurfürst
Again, the FACT is the DVL doc shows 55deg/sec roll rate 375mph IAS, which is better than the Zero, Typhoon, Spitfire, P-39, F4F, and almost as good as the P-47 or F6F. As usual it is the case that gripen claims something with reference to a document, but the document doesn`t shows what gripen says it say.

It's not a public problem if you can't make DVL and NACA data comparable. At 375 mph IAS and with 50 lbs stick force, the Bf 109 is about equall with the Zero and Typhoon as Mr. Knegel's presentation shows. At higher speeds the Bf 109 is worse.

Originally posted by Kurfürst
If you really wish to prove the 109 had higher stickforces than others, why not posts stickforces themselves vs. other planes?

It's not a public problem if you can't read the NACA chart, it gives directly the roll rates with given stick force (50 lbs).

Originally posted by Kurfürst
Easily reachable? That`s merely an opinion of yours. Basically you say that at speeds that wouldn`t even be reached by 90% of all WW2 fighters at 10k ft, the roll rate of the Bf 109 is bad.

400 mph IAS at 10k is not particularly high speed, even the Bf 109E and Spitfire I were tested up to that speed by RAE much earlier than DVL test. And as noted above, it's well below normal flight limitations at 10k.

gripen

[Kurfürst]

Yep, HoHun is right. I must admit I admire his ability to put as much faith in the public`s common sense that it can filter the true facts from the silly mantra of an self-proclaimed 'expert on all'.

HoHun is right. Who the f. cares what gripen mumbles. He can post his sillyness for himself and be always right in that.
You don`t worth an answer.

[Knegel]

Hi,

the 109 roll very bad at highspeeds over 350mph, but up to 280mph the rollratio was ok for its time and even up to 340mph it was good, although the stickforces was pretty high.

If we consider that the best sustained  turnspeed of the powerfull La7 was 200-210mph(320-340km/h) IAS at sea level and only 175-180mph(280-290km/h) IAS in 5000m alt (less powerfull planes, had best sustained turn speeds good below that of the La7!), we can get a imagination what speeds IAS was common while a combat. Next to this there must be a reason why the Brits tested the SpitfireVa and HurriII only up to 300mph.


So the people who wanna see the Be109 in a bad light dont will stop to point to the bad highspeed behaviour, while the people who wanna show the Bf109 in a good light, will point to the advantage over the Spit and Hurri at slow to medium speeds.

Btw, i would like to know where the very high 'Spitfire (normal wing)' datas in the NACA document comes from.

Did they made more changings to the metal covered alerons to obtain such a rollperformence?

And it also would be interesting to see the original tests of the other planes next to 109G and K roll tests.


Greetings, Knegel

[Angus]

I belive the Spitfire was under constand "edit" in the rollrate field from MkV onwards.
So, was the 109.
BTW, some WW2 monsters reach 400 mph at SL, so, you'd want them to be able to bank.
Now for Kuffie, - ease off a bit will you.

[Knegel]

Hi,

Kurfi, cant you accept german testdatas too?? The 109F was bad at highspeed roll in comparison to ALL other WWII fighters shown in the NACA test. Where is the problme?? Most planes was more bad up to 200mph.

Angus, at 400mph the 109 still could bank 90° with 2,3sec, although high stickforces are needed, this is far away from not manouverable, if we consider that one turn manouver let fall the speed fast much below Vmax!  If the pilot would need to bank many times at 400mph the limited constant manpower would be a real problem for sure.

The 109F simply wasnt made to fight at such speeds and i guess the 109G10 and 109K4 made this job better.

I think the results of the 109F in combat show pretty good that the rollratio same like the other flightperformences wasnt its handycap, rather its armament.

Greetings, Knegel

[OttoJ]

Originally posted by gripen
In the case of the Mustang III, RAE went even further and tested ailerons up to about 470 mph EAS at 10k:

EAS? Estimated Air Speed?

470 mph IAS at 10k is ~564 mph TAS. Did they put rockets on this Mustang?

Are you sure about these numbers?

[Kurfürst]

Kneagel I think you took the IAS/TAS conversion wrong.

Here`s my version. I used a Rechlin flight test that lists both IAS and TAS for 3000m, so it`s more accurate to show German conditions. IAS conversion is effected by a lot of factors, and standard day conditions are different from country to country, so even small errors can lead to big differences, see below.

I used  1 IAS = 0.861 TAS conversion, not the scientific gripen "roughly 20%". It should reflect German IAS conversion standards.



ERRATA : The blue "30 lbs" (I don`t know if it`s conversion quality error or typo) is showing the 50 lbs line for the Bf 109, not 30 lbs !

I don`t really see how the roll rate bad. It`s about avarage on the whole range in the group.

[Kurfürst]

Butch made some interesting comments on the other thread, I think it`s wortwhile to qoute him :

This document (which i own as well) is nothing new nor does it contradict the other German documents i have pertaining to 109 Roll rate. Actually it is much worse that the calculated data i have which for instance give the 109F a roll rate of 95°/s at 480km/h....

Second a 66lb stick for is something which can be achieved easily by someone trained and fit. I used to be an archer when i was younger and used a classic bow rated at... 66lb. It is straining at first but with training and excercise and an healthy life you could maange it easily. Sure if you suffer from a serious hang-over it will definitely put some strain on your shoulder
On a Warbird one must distinguish the left side roll from the right side roll, the later if measured single handled is usualy worse because of :
THe cramped space impeding proper arm movement
The lesser power achievable by the muscles in such a movement.

The left roll is easier due to upper torso muscles being used to full extent.

Now is 66lb achievable on a constant basis, definitely NO. It is straining and could be achieved for short amount of time and can be repeated a few dozens of time during a day. This provided you are well trained and healthy. I insist on hte later point since i could experience the effect of not being well feed or having drink too much the day before competitions...

On a punctual basic one can achieve much larger effort for small amount of time. 100lb or more can be achieved due to adrenalin boosting your muscles. The day after won't be one you'll be wishing to fly because your arm will most likely be sore. Once again that's something i experience when training my upper body muscles.

Frankly the 50lb limit usualy seen in documents is more for comparison than a physical limit. THe only physical limit it may represent is tiredness. At 50lb you do not tire much provided you are used to such efforts. Given the training the flying cadets had to undergone, i believe they should not have much trouble pushing/pulling 50lb ever way and doing this repeatidly.

That's my .02$ worht of comments.

Ie. butch`s other doc gives 95 deg/sec roll rate at 480 km/h, ours give at this speed 80 deg/sec. I guess it comes down to variations between individual planes. The NACA/RAE chart shows the highest values for any Spit in roll I have seen so far (and I seriously doubt the clipped figures would come from flight tests, all other documents contratics such a great and linear change), so it`s probably a better example of the aircraft.

BTW Spitfire fans always complain about that 1941 NACA test on the SpitV, dismissing the results completely based on Nashwan`s claim that it was 'very tired', now I wonder what`s in the case of the 109F-2, which was built in late 1940, and tested in late 1944, a four years old machine.. still, it did quite well imho.

[pasoleati]

Originally posted by OttoJ
EAS? Estimated Air Speed?

470 mph IAS at 10k is ~564 mph TAS. Did they put rockets on this Mustang?

Are you sure about these numbers?

EAS=Equivalent Air Speed. It is TAS with compressibility correction.

[pasoleati]

Kurfy, in pursuit of your agenda 109 you have sunk all time low. You have become a true believer now. Only a true believer can twist the presented data as you are now doing. Sad.