Originally posted by gripen
Actually I'm talking about that with others. It should be noted that we have at least anecdotal evidence on condition of the airframe from Stanford Tuck:
"It happened that Wright Field had the only Spitfire in America-a Mark V. Unfortunately almost every pilot in the Air Corps had had a go on her and like a car that had too many drivers, she was the worse for wear...'She was very tired, very sloppy-she'd had the guts caned out of her all right."
This count mainly for the wingtwist, but the cables for the linkage can get adjusted, they dont get more soft cause they are old. If a real lose linkage would have caused this incredible different, they would have had 5° or more 'deadzone' for the stick, but thats of course BS. And again, a lose linkage cause a increased speed of max stick deflection, not a decreased.
Originally posted by gripen
I have allready told you that:
NACA comparison is comparison made by NACA and the tested planes were the P-36, P-40, Hurricane and Spitfire. The tested Spitfire was same as used for flying qualities tests and no wing twist was errorneously claimed for this plane by NACA in the report on flying qualities.
RAE fighter aileron comparison (RAE 1231 and other reports) is an aileron comparison made by RAE and amount of wing twist was measured for all tested planes and these roll rate curves can be found also from NACA 868.
I was talking about the NACA comparison, which include the FW190.
Originally posted by gripen
That is because the chart is rough and wing bends quite steadily when the speed increases:
Calculation to check if the twist is there at 200 mph EAS (roughly):
Rigid wing and linkage: 22deg x 6(deg/s)/deg = 132 deg/s
Elastic wing and linkage: 20deg x 5(deg/s)/deg = 100deg/s
How do you know the aleron deflection??
We also could calculate this:
Rigid wing and linkage: 18deg x 6(deg/s)/deg = 108 deg/s
Elastic wing and linkage: 16deg x 5(deg/s)/deg = 80deg/s
Originally posted by gripen
I wonder what do you mean? The roll rate curve is indeed strange but I have no problem to believe if it is about correct for this particular plane at given condition. And the RAE curve might look strange due to rough nature of presentation but there is 100% certainty that the curve contains the twist as well as elasticity of the linkage.
But you have problems to believe it was normal.
Originally posted by gripen
pb/2V is helix angle of the roll ie angle of the wing tip motion during the roll.
-Kb2 (or Kb2 with negative values) is aileron response factor ie relation between stick force and aileron angle.
If you are interested, following RAE report describe it:
"Handling Tests on the Curtiss H-75, and Comparative Aileron Tests on the Curtiss H-75, Spitfire and Gloster F.5/34" RAE report No, B.A. 1583.
gripen
Aha, thanks for the clarification. But you realy think they was able to get credible results out of TWO measured points with a bit high alerondeflection, while we see how bad the mesurements fit to the linear curve?? Calculations to even more alerondeflections they only can make if they have a worthy number of measured points for at least three different aleron delfections. But they only have one aleron deflection with many measured points. The linear increasement stay a assumption without base.
Originally posted by gripen
There is no need to be exact, 5 deg differences in the roll rate are neglible and given the amount of data, the error is probably less than 5 deg.
5° with the not used 0,5° different aleron delfection between 200 and 400mph, based on the few measered points! If it was 1° with 17° aleron deflection at 257mph, the different would be already 10°/sec.
Originally posted by gripen
Why don't you just go and read the RAE report on Bf 109E before you claim something about it.
Probably its made in best position for the Spit, and in badest position for the 109, like most of the tests, made with that 109E, to show how bad the 109 was.
I only know this often offered results.
Minimum radius of turn without loss of height......... ft. 696(Spit) 885(E3)
Cooresponding time to turn through 360 deg........ sec. 19(Spit) 25(E3)
But anyway, i dont think it make much sence to look to the british turn tests of this 109E3, the french tests with this planes show particular big differents, what show that the engine was under bad conditions, but with a bad engine the turntime would also decrease much(same like the climb).
Originally posted by gripen
In the old days before the computer radios this was the linkage we used to use to get differential aileron motion in the RC-planes.
Still the same if only one servo get used.
Originally posted by gripen
Yep, I've said that in my reply to Niklas few days ago; it depends on geometry of the linkage.
gripen [/B]
This could explain the relative good results at highspeed, but not the extreme low speed of max stick delfection! A lose linkage would let increase the speed of max stickdeflection!
Niklas,
the Spit5a rollcurve show a speed of max stick deflection only up to 130-140MPH, above this speed the stick deflection isnt constant!! Therfor the curve can have many different results, depending to the leverage and aleronbehaviour(the increasing rollratio with constant stickforce is not common).
The Spit roll curve, where i cant understand a linear increasement, have a speed of max stick deflection of 200mph! So the stick position was constant. To show a linear roll increasement with a constant stickposition, the linkage and wing must have been rigid.
Even at the highest point, where the stick forces and aleron forces are most big, there is nothing to see(even the FW190 show this, due to wingtwist).
If you insert the roll curve into the NACA comparision(with FW190), you will see that the SpitVa curve inst linear too in that relationI did this some days before, unfortunately with the more slow, right roll).
Greetings, Knegel
