Author Topic: Me-109 turn to right widely said to be poor; any clues?  (Read 9717 times)

Offline Die Hard

  • Gold Member
  • *****
  • Posts: 2205
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #45 on: March 30, 2009, 09:09:47 AM »
     Interesting idea about the tail-high attitude, Charge!

     I myself have been wondering if the square wingtips don't bring more lift by leverage, because a broader wing surface area further away from the weight of the fuselage would have more "leverage" against that weight...

No it wouldn't. A pound of lift is a pound of lift no matter where it is created on the wing.
It is better to be violent, if there is violence in our hearts, than to put on the cloak of nonviolence to cover impotence.

-Gandhi

Offline Charge

  • Gold Member
  • *****
  • Posts: 3414
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #46 on: March 30, 2009, 10:08:51 AM »
"I myself have been wondering if the square wingtips don't bring more lift by leverage, because a broader wing surface area further away from the weight of the fuselage would have more "leverage" against that weight, maybe delaying the true stall and allowing a more prolonged "mushing" behaviour while a pointy tip wing would have stalled outright."

AFAIK thats what angular wing tips actually do but not quite like that. I saw someplace a pressure distribution plot for an angular wing and it pretty much explained why an elliptical planform is more desirable if pressure distribution (dragwise) is considered, but unfortunately it also partly causes the wing to lose all of lift at the same time at critical AoA, unless there is wash-out, and in case of Spitfire as a representative of elliptical planform, there is, and I have understood that it works if you don't approach the stall too rapidly. If you do and the wing loses lift all at once you have a very serious stall there.

In fact I suspect that clipped wing Spitfire was a tad more forgiving in accelerated stalls compared to normal wing Spits although there is no anecdotal evidence that this was the case. Of course the same goes for 109E and 109F too.

-C+
"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline BnZs

  • Platinum Member
  • ******
  • Posts: 4207
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #47 on: March 30, 2009, 11:56:44 AM »


    BnZ says I mention tests nobody has ever heard of, well here it is; the test most relevant to my argument of poor 190 handling at high speed vs P-47D-4 (and of increasing P-47D turn rate past 250 MPH!). I did mangle some of the wording, but the points all bear out my claims;
           
           http://img107.imageshack.us/img107/9568/pag17bm.jpg

This links to an image of an acceleration test. It is stated that the 190 accelerated better below 350mph at low altitudes but above this speed the P-47 began to catch up. This difference is hardly surprising given the 190s better power/mass and the P-47's lower drag. Nothing to contradict flight physics as the rest of the world has learned them or to confirm some of you more wild idea. It is hardly a revelation that the P-47's turn rate would increase above 250mph IAS, given that 250 is still below the Jug's corner velocity.

       


     
       Incidently, I happen to believe the delayed response to elevator input control is obvious from much WW II footage depending on speed, and is probably a great unexplored area of WW II aircraft performance... Pilot/stick, stick/pitch, and pitch/trajectory are all areas of large variables in my opinion for elevators.

If you can pull back on the stick to deflect the elevators (below compressability speeds), they WILL create the forces that change pitch, and thus AoA. It is that simple. An elevator deflected fully up for example would create even more down-force on the tail to pitch the nose up at 300mph IAS than it would at 200mph IAS. The only variable is how much the pilot is physically able to deflect the elevator. Stick forces in the 190 were apparently quite trim dependent, a factor which may easily explain seeming contradictions in reports of that airplane's elevator authority at high IAS.




      Returning to the comparative turn test, NO mention is made of a speed zone of relative equality in turns, which I find VERY telling. To me this probably means the P-47's turn response is STILL improving past 250 MPH, while the FW-190's is rapidly descending. Recent (1990!) tests of the P-51 and P-47 found the pilots saying the peak turn rate was MUCH higher than they expected, leading them to conclude that low speed turn performance was probably not that good...


The oft-quoted 8g corner speed for the P-51 of 270mph IAS is with one notch of flaps and at 9,611 lbs. Heavier weights, a clean configuration, or pulling additional Gs will all cause an increase in the needed airspeed. Once again, this does not mean aerodynamics as the rest of the world knows it is wrong.

And of course, a prop fighter cannot sustain its corner speed without descending precipitously. As a practical matter I would not deliberately slow a P-51 down to 270mph IAS initially in a dogfight. I think you have mis-extrapolated a lot of anecdotal information that comes out of the complexities of air combat into wildly erroneous speculations about airplane performance. If you had any actual time in a good prop combat sim, these factors would not be so confusing to you.


 U.S. pilots describing an 8000 ft. minimum to start pulling out or else...

   

An airplane diving straight for the ground at 460mph TAS would be descending at a rate of 40,480fpm! That is 5000 feet to *splat* in 7.4 seconds, assuming the local terrain is at sea level. If you are possibly dealing with heavy elevator forces, (possibly having to fool with the trim to reduce them) then yeah, you are quite probably going to lawn-dart. Nothing surprising here. Oh yeah, and if you've caught a stray .50 cal in the head, you are probably going to lawn dart.




 The INNUMERABLE descriptions of "pankaking" 190s, of which not one I remember concerning the 109... There IS a pattern here...

   

Still you fail to grasp that a "pancaking" airplane does not indicate poor pitch authority, it indicates the opposite. The "Pancake" crash while trying to recover from a dive occurs when the airplane does not have the lift available to alter the trajectory of the airplane enough to avoid hitting the ground and the pilot pulls it into an accelerated stall trying. (Everyone who has played a combat sim is quite familiar with this effect BTW) Obviously this would be more likely to occur with airplanes that have a very wing-loading...like say Fw-190s. Once again, the ability to pull an airplane into an accelerated stall at a given speed indicates pitch authority, not the lack thereof!!!

      I think YES the 190 could pull 7Gs on pull-outs, but there could be a very long "lag-time" for that response to happen, and even when it DID happen, much of those Gs could have been generated in deceleration by an abruptly shifting, "automatic" tail-down "sinking", not turning, leading to the following inferior performance compared to an aircraft not immune to "sinking" itself!;

Hogwash. "Gs" (in the sense normally used) occur when the airplane's wings develop lift, period. Once again, sometimes the lift developed may not be enough to alter the course of the aircraft enough to avoid the big splat, but so what?
     

The actual FW-190A-8 ace on this Forum mentionned "catching" the stall with the ailerons, after a slight forward push on the stick, choosing extra aileron chord to boost this, boosting this further with SPACERS, having the broad wood prop, etc... You don't think American test pilots were that well versed in those shenanigans, do you?

Every real pilot is familiar with recovering from a stall by easing forward on the stick to reduce AoA. Every pilot familiar with high-torque single engine jobs either in reality or a sim is familiar with doing this plus using some aileron input to "catch" a dropping wing. If you had any hands on familiarity with flying, even well-simulated virtual aircraft, these things would not be such great mysteries to you.


   
his is a turn rate performance chart from actual flight data comparing the heavier F-86 Sabre to the lighter Mig 15, both maximum and sustained. Josf14, in the following thread, makes quite a messianic point that this actual data chart goes against every precept of wingloading calculations, because the heavier/weaker thrust F-86 beats the lighter more powerful Mig-15 at low speeds in maximum turn rate.

It is odd you think relative performance of the F-86s vs. the Mig-15 is damming to physics, since there is negligible difference between the wingloadings of the aircraft. And of course wingloading and power-loading is merely a good indicator of relative performance. Other factors come into play when figuring sustained turn rate, such as the wing's l/d efficiency. Good example of this is the Ta-152. Better sustained turn rate than many lighter loaded aircraft because the high-aspect ratio wing is efficient. However, this speculation of making an aircraft turn better by INCREASING the weight...hogwash, if this were the case they'd have armor plated an airplane to create the uber-fighter.
« Last Edit: March 30, 2009, 12:01:12 PM by BnZs »
"Crikey, sir. I'm looking forward to today. Up diddly up, down diddly down, whoops, poop, twiddly dee - decent scrap with the fiendish Red Baron - bit of a jolly old crash landing behind enemy lines - capture, torture, escape, and then back home in time for tea and medals."

Offline Murdr

  • Platinum Member
  • ******
  • Posts: 5608
      • http://479th.jasminemaire.com
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #48 on: March 30, 2009, 05:44:50 PM »
     This is a turn rate performance chart from actual flight data comparing the heavier F-86 Sabre to the lighter Mig 15, both maximum and sustained. Josf14, in the following thread, makes quite a messianic point that this actual data chart goes against every precept of wingloading calculations, because the heavier/weaker thrust F-86 beats the lighter more powerful Mig-15 at low speeds in maximum turn rate.

The thrust efficency vs speed paradigm for jets is different from propellers.  Hmm, two swept wing jet fighters from different countries...Two prop WWII varients of the same airframe... "Why do these charts look different?"  Well DUH!

Quote
beats the lighter more powerful Mig-15 at low speeds in maximum turn rate.
Obviously you don't understand what you're looking at becase this statement is factually incorrect.  Your referenced poster also seems to have that problem when he plops a dot in the middle of the chart and says the F-86 is stalling.  Not to mention you're still going off on this ill concieved "wingloading calcuations" line, when you really have no clue of the factors and parameters that this or any other sim takes into account beyond (appearently) what you've read lerking disccusion forums.

I already provided you with a real vs AH flight model E-M analysis in the other thread.  Why don't you try apples to apples instead of apples to anvils or kitchen sinks, or whatever other irrelevent topic you'd like to bring up next.




Offline Noir

  • Platinum Member
  • ******
  • Posts: 5964
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #49 on: March 30, 2009, 05:47:21 PM »
Quote
if this were the case they'd have armor plated an airplane to create the uber-fighter.

Ok lets put some lead weights on a zero see how it goes :)

Quote
but neither of the american aircraft were known for their zoom (the Ki-61 would out-zoom the F4U-1!),

Mmmmmmmh what ? IF the F4U-1 is not known for its zoom then what plane is ?????? Never Heard of a Ki-61 out-zoom a F4U....And a F6F hanging with a Zero is turns...Lol !!! The F4F couldn't hang with the Zero, and you think the heavier F6F could do better ? Don't try this at home kids !
now posting as SirNuke

Offline Gaston

  • Copper Member
  • **
  • Posts: 172
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #50 on: April 01, 2009, 02:52:28 AM »
     To answer Noir; The Zero's turn margin narrowed or disapeared above 250 MPH...

    And yes the Ki-61 would use the zoom to get away from the F6F-3 AND the F4U-1, as a rare actual Ki-61 pilot account described; "I could use the zoom climb to get away from the F6F and EVEN the F4U, but against the P-38 this tactic did not work at all. Never had I found myself in such a predicament."

  
Quote-"This links to an image of an acceleration test."

     -You didn't use the LATER posted DOUBLE link (My fault for the omission of the second page!); ARC's S&C 1718 of April 24 1944 is NOT just an acceleration test. Your answer does not address the VASTLY decreasing FW-190A higher speed turn rate above 250 MPH that is apparently news to people here, and a supposed FW-190A strong point (roll eyes)... Such a strong point an experienced German ace, fighting for his life, will LOWER his speed and pop the flaps before engaging P-51s... (Not a wild idea this, but an actual quote from this forum from an experienced 190A-8 ace with a demonstrable track record of shooting down P-51s...)

     In addition, the ARC report clearly mentions the turn disparity KEEPS increasing with speed past 250 MPH, starting from immediately severe to increasingly severe. In other words, the transition is sufficiently harsh it does not really even flatten out or much less narrow down with speed, this despite the FW-190's ability to to pull 7 Gs, after a looong pull, which is probably equal to the P-47's best Gs, but is apparently not impressive enough to get mention in the report as tightening the disparity at some point... Now that probably means the G's in the 190 are not as useful trajectory-wise as G's in the P-47D's more gradual control response...

       


     
Quote-"If you can pull back on the stick to deflect the elevators (below compressability speeds), they WILL create the forces that change pitch, and thus AoA. It is that simple."

    -Stick forces are one thing, elevator effectiveness another, and pitch effectiveness yet another...

    You don't address the multiple reports of poor 190A pull-out behaviour. You don't address this report's "tendency to black-out the pilot", which is HIGHLY significant. You would say, according to your above quote, that the P-47D ALSO has a tendency to black-out the pilot if he pulls hard enough. But note that THEY RESERVED the negative to the 190A. Why? Because the 190's high-speed elevator response DOES NOT follow your progressive response theory, and THAT is the only explanation for this comment; the 190A has a tendency to not respond (either in stick force, in pitch, or in lift, or a combination of all three) for a LONG while, and THEN it responds abruptly BEFORE the pilot can alleviate the response. And this NON-gradual response obviously makes the possibility of a smooth gradual pull-out unlikely, and instead it causes a brutal level attitude sinking that would indeed be HARDER on the pilot and at the same time create a mediocre angle of pull-out. No other WWII prop aircraft that I know of has its poor high speed handling described so precisely and consistently in this particular way. You seem happy to ignore that I have quoted this peculiar behaviour from E. Brown, Russian "perfect hanging target" combat, several "pancaking" quotes from U.S. pilots, the Dec. 2 '44 Murrel combat report, and last, but not least, the Aeronautical Reseach Committee's S&C. 1718's fly-off between the P-47D-4 and a 190A-5, a report which, by the way, makes the Farnborough's vaguely-worded fly-offs look like they are intended for the schoolyard...

    




Quote-" If you had any actual time in a good prop combat sim, these factors would not be so confusing to you."

Quote-"An airplane diving straight for the ground at 460mph TAS would be descending at a rate of 40,480fpm! That is 5000 feet to *splat* in 7.4 seconds, assuming the local terrain is at sea level. If you are possibly dealing with heavy elevator forces, (possibly having to fool with the trim to reduce them) then yeah, you are quite probably going to lawn-dart. Nothing surprising here. Oh yeah, and if you've caught a stray .50 cal in the head, you are probably going to lawn dart."

    -I didn't say straight down, I said around 500 MPH, which could easily mean over 10-15 seconds at 45° from 8000 ft., with several observed ineffective nose pull ups (which were probably in my opinion more like several ineffective tail push-downs), until finally an abrubt nose-up flattening out, followed sometimes(often?) by an even more abrupt pancaking...
    
    Am I to undestand that flight simming experience beats quotes from actual WW II combat pilots? Why don't you find me a combat quote of great 190A high speed handling for FAST dive pull-outs and anything not related to the ailerons? I'd be curious to see that... There are hundreds of actual U.S. combat reports if you google the "WW II aircraft performance" site...
 




Quote-"Hogwash. "Gs" (in the sense normally used) occur when the airplane's wings develop lift, period. Once again, sometimes the lift developed may not be enough to alter the course of the aircraft enough to avoid the big splat, but so what?"

    -Well, if the lift comes too late, and ALL AT ONCE, not giving a chance for a trajectory change, that's not "so what". And that's why the 190 "has a tendency to black-out its pilot", while they stay mum on this about the P-47, despite the heavy jug being also capable of some sinking, just not as abruptly...
     

Quote-"Every real pilot is familiar with recovering from a stall by easing forward on the stick to reduce AoA. Every pilot familiar with high-torque single engine jobs either in reality or a sim is familiar with doing this plus using some aileron input to "catch" a dropping wing."

   -Oh yeah? When have you last heard an experienced P-51 pilot selecting longer-chord ailerons, made specially for the purpose, to catch his stall? Note that longer-chord ailerons implies sacrificing high-speed roll, which high-speed performance the German ace did not apparently care much about, since he made his high-speed leverage even WORSE by adding SPACERS on the hinges. When was the last time you heard a P-51 driver do that?

Quote-" However, this speculation of making an aircraft turn better by INCREASING the weight...hogwash, if this were the case they'd have armor plated an airplane to create the uber-fighter."

    -Oh, I was expecting this one... Note that I said weight CAN improve the LOW-speed turn UP TO A POINT. Although most German low-altitude tests agree the 190A OUT-TURNED the 109G, it probably wasn't by a wide margin for the earlier models, since Gunther Rall said "Yes they told us the new 190 would out-turn the 109, but(insert smirk here) for ME at least, I could out-turn it..." This is a reference to earlier FW-190As, and ALL 190 pilots agree the HEAVIER 190A-8 was a MAJOR advance in turning agility, but IN the 190A's strong areas, not high-speed/high-altitudes where the 109G was vastly superior, as a late '44 high-altitude test demonstrated with AS gustavs against the even more powerful 190A-9. (The 109s basically made fun of them...)

    What I really said was that at LOW speeds, higher weight was not in PRACTICE the absolute penalty it is assumed to be, and I speculated that the top-heaviness of higher weight allowed more readily a slanting off-center of the thrust axis into slower relative airflow. Hence "Hanging on the prop". This would explain German pilot enthusiasm for the A-8; the only real difference with previous models was the significantly higher standard power of 1.58 ata, combined with perhaps essential cg alterations...

    Listen to ANY U.S. veteran pilots of summer/late '44, when most of the combat shifted to low altitude; ALL agree the 190A of that time frame turned better than the 109G; that was the heavier A-8. As 1944 progressed, the FW-190A's presence grew to represent 70% of Western Luftwaffe fighter strenght, the 109G being apparently still better suited to the Eastern Front (still having a high altitude advantage against Soviet types).

    I will post again the link to the second page of the ARC S&C 1718 report, since some have missed it.

    
                               http://img105.imageshack.us/img105/3950/pag20pl.jpg
    first page;
                              http://img107.imageshack.us/img107/9568/pag17bm.jpg

     The above is perhaps among the best-written, most informative WW II side-by-side tests I have seen. I wish they were all this good...

     The Zero 52 evaluations versus the P-51D/P-47D-25/P-38J were also unusually good (On the "WWII aircraft Performance" site this time)


     And again for good measure, in case you missed it, this Murrel combat report, at the FW-190-friendly altitudes of 20-10 000 fts. Note the complete inability to turn at high speed, the elongated loop, and the 400 MPH speed at the end.

     http://www.spitfireperformance.com/mustang/combat-reports/20-murrell-2dec44.jpg

     Thanks Charge, for explaining why the leading edge washout was more important on pointier elliptical wings...

     As for everyone else who still clings to the notion of a happy handling high speed FW-190A-8, that is DISADVANTAGED by low-speed turning(roll eyes...), I would like to see some anecdotal evidence other than Kurt Tank's 7 G "pull-outs", as the above test, AND Eric Brown, AND the Russians, AND others so numerous I forget don't seem so optimistic...

     If all else fails, some pancaking Me-109s would do...


     Gaston.






    
  





    
« Last Edit: April 01, 2009, 02:55:51 AM by Gaston »

Offline BnZs

  • Platinum Member
  • ******
  • Posts: 4207
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #51 on: April 01, 2009, 04:55:45 AM »
   

    
 Such a strong point an experienced German ace, fighting for his life, will LOWER his speed and pop the flaps before engaging P-51s... (Not a wild idea this, but an actual quote from this forum from an experienced 190A-8 ace with a demonstrable track record of shooting down P-51s...)


Because you, frankly, do not know what the F you are talking about in regards to ACM, you do not realize how being slower than your opponent can win the dogfight, regardless of putative turn performance. The 190A at high altitudes is outperformed by the P-51. Nor is a prop airplane, already laboring with a worse powerloading at this high altitude, and a wingloading of ~45lbs/foot going to overcome another prop airplane with a wingloading of ~40lbs/foot in the realm of pure turning. What remains in the bag of tricks for the expert pilot is scissors/overshoot fighting, the race to get slower fastest.

BTW, I caught you trying to deny aerodynamics 101 again. There are no "useful" and "useless" classes of Gs. Two airplanes pulling the same Gs at the same speed WILL have the same rate and radius and turn at that particular moment in time. This is not up for debate.

    

    And again for good measure, in case you missed it, this Murrel combat report, at the FW-190-friendly altitudes of 20-10 000 fts. Note the complete inability to turn at high speed, the elongated loop, and the 400 MPH speed at the end.

This report *clearly* describes the 190s as having the ability to pull into an accelerated stall multiple times during the fight! For the umpteenth friggin' time, the ability to pull into a stall does not mean you lack sufficient pitch authority, it means the exact opposite. The 190 is also described as pulling "streamers", IOW vortices from the wingtips as the wing approaches critical AoA. Once again, this indicates the 190s have the pitch authority available to pull a turn as hard as is physically possible for the airplane to do without stalling. The 190 is described as being able to pull these "streamers" at an estimated 400mph! IOW, in this particular case, the elevator is working just fine! The P-51D pilot speculates that the 190 pulled enough Gs to black out...once again, if correct, this does not indicate poor pitch response, it indicates the exact opposite.

 The P-51s for their part, are able to easily turn inside the 190s in the initial level turn...not surprising for airplanes which possess that sort of wingloading advantage. It is amazing to me you posted this report as "evidence", the events described totally contradicts what you have been trying to prove. Once again, you have wildly misinterpreted what you were reading due to an utter lack of either academic or hands-on knowledge of basic aerodynamics and ACM.
« Last Edit: April 01, 2009, 04:59:03 AM by BnZs »
"Crikey, sir. I'm looking forward to today. Up diddly up, down diddly down, whoops, poop, twiddly dee - decent scrap with the fiendish Red Baron - bit of a jolly old crash landing behind enemy lines - capture, torture, escape, and then back home in time for tea and medals."

Offline Charge

  • Gold Member
  • *****
  • Posts: 3414
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #52 on: April 01, 2009, 07:30:43 AM »
Since BnZ pretty much has the point here considering the elevator authority I'd also like to add that in P47 vs FW190 case it is not physically possible that a 190 turning worse would black out the pilot and  a P47 turning better would not, since the fact is that the ability to turn itself produces Gs. This particular description of the mock fight merely describes how a slower flying P47 is able to turn behind a faster flying FW190 pulling too much Gs, i.e. the P47 is "cutting the corner".

In a dogfight the one flying behind another always has the option of reducing speed and turning tighter i.e transferring turn rate to turn radius, than the target that relies solely on turn rate, that is if the qualities of the pursuers plane make that possible. I'm sure German pilots who flew captured allied fighters made similar non-scientific "user experience" statements which some where correct and some probably did reflect the actual abilities of the planes but in such context that their true meaning to other plane's relative performance was unclear or outright erroneous. That means you have to have a deeper understanding of what is actually going on when you read those test reports, unless the test method is adequately described and results measured with adequate accuracy -i.e. meaning they are scientifically valid. They usually are not, nor all the participants have adequate experience of training to interpret their observations in relation to hard fact. The same goes for any combat record. An error made by opposition (usually leading to a kill claim) does not necessarily reflect the bad performance of the plane but a bad choice of tactics which ultimately leads to the demise of the pilot in the receiving end...

I have previously posted a link to a video where a 190 handily out turns a P47. That does not reflect the actual turn performance otherwise than that 190 could do it, but it  d o e s   n o t  mean that 190 was the better turner. It just means that P47 was pulling "streamers" in higher speed and the pursuing 190 happened be on a speed range where it could fly a bit slower and match the turn rate of the P47 with its resulting smaller turn radius. I think any virtual ace would have used the excess energy the P47 had in that video a bit differently than wasting it in trying to turn with a plane which obviously could match your turn at that particular speed range. But then again we have the option to try again if something does not work out right and learn -and we don't have four 20mm pointing to our head like the P47 pilot in that video had.

There was also a story by a Spitfire pilot how his low level flight was bounced by a group of FW190s and he describes how a 190 was gaining on him even if he was blacking out trying to evade them. Let me analyze that situation here: Firstly 190 had a better reclined seat compared to Spit so the 190 pilot probably was not blacking out unless he was turning inside Spitfire in equal or greater speed meaning that 190 was also gaining in distance. So at certain speed the pilot's G tolerance becomes the deciding factor, not the actual turn ability of the aircraft (you may also consider the G tolerance of the aircraft itself which is very high for the FW190 due to small loading of wings and very rigid construction). Second factor to be considered is the compressibility of air (if I got the term right for this use!?!) which possibly dictates that at certain speed the wingloading becomes more and more insignificant, meaning that while at slower speed to have equal turning ability you need more AoA for the smaller wing to match the loading of a bigger wing, in higher speed the difference becomes smaller but it never goes away, again meaning that a bigger wing always has the edge in turning over smaller wing unless significantly handicapped by planform or profile. But the form drag may become an issue at this point making the bigger wing more prone of drag build-up in maneuvers as I suggested in my earlier post. However considering this I have no idea if WW2 era planes could operate at speed ranges where this factor would have been deciding.

As usual have a grain of salt with these ponderings.  ;)

-C+




"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline Murdr

  • Platinum Member
  • ******
  • Posts: 5608
      • http://479th.jasminemaire.com
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #53 on: April 01, 2009, 04:37:46 PM »
     Am I to undestand that flight simming experience beats quotes from actual WW II combat pilots?

No, I believe he is saying that if you actually had knowledge of theoretical and practical ACM tactics and geometry, and a better understanding of flight phisics, you might be in a position to better understand first hand sources.  As opposed to wildly jumping to the wrong conclusions :)

Offline Gaston

  • Copper Member
  • **
  • Posts: 172
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #54 on: April 04, 2009, 06:26:03 AM »
     I'll try to be brief but...


     The 190A in the Murrell combat report is going at high speed throughout, except perhaps when pulling-out at the end, agreed?

     As it tries to turn with the P-51D, it mushes through the turn, because it has plenty of elevator authority, but the change in pitch is probably mostly tail-down and not nose-up, which means that what is occurring is a poor, but not seriously delayed, turning response. This would probably require the German pilot to perform constant aileron roll reversals in a downward spiral to compensate the slow FW-190A's turns against the P-51D, while managing to keep the speeds as disastrously high as he did...

     To the P-51D pilot, it looks as if the 190A is responding without much lag-time, but is not turning as hard as the P-51D can.

     Then the 190 pilot tries to prolong his poor mushing turn one way only, without switching sides by rolling, to try to slow down to finally get some better turn performance, when the wing's lift FINALLY, and abruptly, overcome the nose-heavyness/momentum, and suddenly the nose pitches up (hence, the "tendency to black-out the pilot", NOT attributed to the P-47...), and the FW-190A appears to tighten its turn dramatically. THEN he snaps out of control, because this abrupt new turn rate is at far too high an angle of attack.

      Quote; "He invariably snapped out of control everytime he REALLY tightened-up his turns." What the P-51 pilot could not know, was that the "tightening up" was the result of staying in the turn, and not voluntarily controlled, which is why the German pilot could not avoid "snapping out" after. In turns, the FW-190's high speed mushing had a limit when the wings started to "suddenly" lift. In dive pull-outs, the "sudden" wing lift leads to an abrupt change to a much less nose-down attitude, maybe even horizontal or slightly nose-up, but the pull of gravity is this time symmetrical on the aircraft, leading to a very "flat" and decelerating pull-out, NOT a "snapping-out".

      Quote; "Finally he pulled streamers at the bottom of an ELONGATED loop, and he seemed to have straightened out a LITTLE going up (meaning the angle of pull-out was FLATTER than the P-51 pilot expected, which he attributed to a VOLUNTARY "straightening out", but was in fact an UNVOLUNTARY shallow angle of pull-out, because at high speed the angle of pull-out of the FW-190A is "inferior", "makes it EXTREMELY vulnerable", "dangerous to dive close to the ground", "making it "hang", creating a perfect target", "inferior to the P-47D, which had a decidedly better angle of pull-out". Should sound tediously familiar by now doesn't it?).

      THEN, right after that pull-out, so mediocre the P-51 pilot thought it was a VOLUNTARY "straightening out", what do we hear coming after that "voluntary" slackening of the pull?  My oh my; "I think he must have blacked-out right then, and I scored many hits"

      Now doesn't THAT sound like "a tendency to black-out the pilot"? There IS such a thing as bad Gs, if the pitch change is TOO brutal and too late in the maneuver, instead of starting gradually and continuously with the stick pull. Pitching up SUDDENLY, and "Sinking" belly first (probably slightly nose-down still), in a malleable medium can lead to a LOT of vertical deceleration, because of the broad surface abruptly presented to the airflow, even if the time of the actual "sinking" is very short. Coming out of the pull-out, the FW-190A is "vulnerable", because either at the pull-out start it is a "perfect" nose-up target, or it is, coming out of it, much lower and slower than its pursuing opponent, and may have in addition a blacked-out pilot!

      The altitudes in the combat report are ALL below 20 000 ft., where the FW-190A has no major engine power inferiority to the P-51. It is the speed the problem here, and it is still 400 MPH for most of the descent, though probably below that after the final pull-out... So it bears out the vast inferiority of the 190A at high speeds, which in this case can only mean that the 400 MPH was maintained by a descending, often reversing, spiral, while at low speeds and altitudes I know of at least three accounts of FW-190A-8s continuously turning, straightening out shortly, then turning again, all the time out-turning multiple P-51Ds (Dec. '44 and Jan 1st '45). Then there is this forum's FW-190A-8 Western ace, who had NO doubt about out-turning P-51Ds at low speeds, in one case to the right with flaps, and would ALWAYS avoid going fast, by downthrottling if necessary... "I had no fear of any other aircrafts in my FW-190A-8". I have yet to hear the Me-109G do the same while not turn/climbing, but at low speeds it probably was a match... to the P-51D with flaps, NOT the FW-190A-8!... The Me-109G could barely match earlier 190s, and I'm sure the later 190A-8, with its greater power and altered center of gravity, could beat the Gustav's turn by a significant margin at these lower speeds and altitudes, and even more so with the broad wood prop!

      At these lower speeds (below 300 MPH for low-level hard turns), there is not quite enough Gs to really black out the pilots for a long time anyway, so if the FW-190As could compete in turns with Spitfires at low level, and at medium-low speeds, it doesn't surprise me. In the initial turn-in against Spitfires, the FW-190A held a short-lived and minor advantage even at slightly higher speeds (300 MPH+), because its initial (30-40°?) of turn had less lag-time than the Spitfire, whose pilot could not start to pull back on the stick more than 3/4 inch(!) without going into its gentle and fully controllable mushing stall. (The Spitfire could always use this, even at fairly high speeds, to shoot precisely accross the circle when attacking, but this was of no use to evade an enemy behind...) This Spitfire lag-time response was less severe at lower speeds, but its comparative prolonged turning advantage was actually much larger at higher speeds. It could compete and win at low speed turning, but would be still penalized by a far inferior roll rate. The late Spitfire's climb rate was definitely its most compelling superiority against the FW-190A.

      I think the 190A-8's greater ability to offset the engine's thrust, outside of the turn into slower air, allowed it to compete perhaps with the later, heavier Spitfires. Certainly it was not far behind at any rate from a MK XIV... Especially with the broad wood prop, and as long as it stayed below 300 MPH.

      The fact that the extremely heavy wingloading of the P-38 allowed it on at least one occasion to compete and then beat the Spit Mk XIV in repeated mock combat should invite anyone to prudence as to the predictions we can make from wingloading...

      I know of one extreme example of a P-38L, at LOW speed, matching for about 360° the maximum turn rate of a Ki-43II Oscar, but it did get the help of a short dive prior to the turn.

      I don't understand why the FW-190A-5 vs P-47D comparison test is not perfectly eloquent as to the superiority of EACH at DIFFERENT speeds. At 5-10 000 ft., The P-47D ALWAYS out-turns the FW-190A-5 above 250 MPH, while the FW-190A-5 ALWAYS out-turns the P-47D below 250 MPH, when BOTH are at equal speed to each other in each of those two bands of speeds. It could hardly be clearer than that, and it completely confirms what I have been saying all along...

      I would like to see my detractors point out a comparative test where the FW-190A-5, and later variants, are better than another aircraft in high speed turns... (A-4s have a shorter engine mount and different cg, so may be a little less "typical")

      Note that, on occasions, the heavy P-47D was considered equal or better in turns than the Me-109G, including by the Germans themselves in mock combat, which, along with P-51 combat reports, brought me to the 109 symmetry issue.

      I have yet to see the issue of off-axis engine thrust at low speeds addressed in any way here, despite the common "hanging on the prop" pilot lingo...

     You may delve into your theories and calculations all you want, but I have provided supporting evidence for my claims, and I haven't yet seen any pilot account supporting the general complete lack of knowledge about the FW-190A's character.

      Gaston.

     

     

     

   
   




     

     


 

   
« Last Edit: April 04, 2009, 06:46:37 AM by Gaston »

Offline Murdr

  • Platinum Member
  • ******
  • Posts: 5608
      • http://479th.jasminemaire.com
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #55 on: April 04, 2009, 04:05:10 PM »
Someone should educate themselves on critical angle of attack and accelerated stalls.  It might save on pargraphs of non-sense.

Offline BnZs

  • Platinum Member
  • ******
  • Posts: 4207
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #56 on: April 04, 2009, 05:54:30 PM »
     I'll try to be brief but...


     The 190A in the Murrell combat report is going at high speed throughout, except perhaps when pulling-out at the end, agreed?

     As it tries to turn with the P-51D, it mushes through the turn, because it has plenty of elevator authority, but the change in pitch is probably mostly tail-down and not nose-up, which means that what is occurring is a poor, but not seriously delayed, turning response. This would probably require the German pilot to perform constant aileron roll reversals in a downward spiral to compensate the slow FW-190A's turns against the P-51D, while managing to keep the speeds as disastrously high as he did...


Oh gack, just admit the Murrel report does not support your hypothesis one bit...it more blows it out of the water. Accelerated stalls when the 190s try to turn harder are clearly described, the fact that wingtip vortices are reported makes the point indisputable.  If the tail goes down the nose *will* pitch up, in turn increasing the wings AoA, until the critical AoA. That anything else is a physical
impossibilty should be obvious to a child familiar with see-saws, to say nothing of an adult supposedly familiar with the dynamics of flight. Furthermore, the P-51Ds easily got on the six of the 190s in a level turn before the descending began, demonstrating the P-51's superior turning ability even before the turn descends and speeds up.

I have posted enough reports from test-pilots flying captured 190s who agree that the 190s elevator is usable until at LEAST 350mph IAS. (Do you know the difference between IAS and TAS at all? Your posts make wonder.) All you have posted are some reports of 190s augering, circumstances vague and unknown, and some speculation that rather badly violates the laws of physics.

All the German flight-test that anyone BESIDES you has ever heard of confirms the 109's edge in the realm of pure turning, as does the Russian commentary. Allied tests confirmed the superiority of the P-51 to the 190 and 109 in turning circle;  However, it is apparent that in many of these tests the pilots though the slats opening indicated stall was imminent, while the airplane can actually be pulled into a somewhat harder turn without stalling after the slats open, a fact belabored  upon by some Experten. "Embarassed by the slats" is the phrasing I believe is used. So the machine was not actually being flown to its maximum potential during these tests. There is no such troublesome device on the 190 to cause confusion.

The P-47D has slightly lighter wingloading than the 190A, legendary stick forces, and maneuvering flaps that can be deployed at speeds up to 400mph IAS. The 190A has superior power-loading. It is unsurprising that the Jug might turn better carrying a little speed into the turn, but that the 190s engine power might let it sustain a better rate as speeds bleed down.

     

     

   
   




     

     


 

   
"Crikey, sir. I'm looking forward to today. Up diddly up, down diddly down, whoops, poop, twiddly dee - decent scrap with the fiendish Red Baron - bit of a jolly old crash landing behind enemy lines - capture, torture, escape, and then back home in time for tea and medals."

Offline moot

  • Plutonium Member
  • *******
  • Posts: 16333
      • http://www.dasmuppets.com
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #57 on: April 04, 2009, 06:00:00 PM »
:lol carriage return warfare
Hello ant
running very fast
I squish you

Offline Murdr

  • Platinum Member
  • ******
  • Posts: 5608
      • http://479th.jasminemaire.com
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #58 on: April 04, 2009, 08:16:52 PM »
The 190A has superior power-loading. It is unsurprising that the Jug might turn better carrying a little speed into the turn, but that the 190s engine power might let it sustain a better rate as speeds bleed down.

Yes, I tried to tell him that weeks ago...
Obviously the lower the available thrust, the lower the best sustained rate of turn and speed are going to be.  So when you reference the P-47D-4 with the Curtiss Electric C542S propeller, vs the captured FW 190A3, I can see why at lower speeds the 190 faired better in that match up.  Even though the P-47 has a more favorable stall boundary for turning and can turn a slightly tighter radius, the 190 can sustain a better rate of turn.  The lack of the later paddle bladed props on the 47D-4 probably only exacerbated the power deficit situation.  However when we take the speeds closer to the two planes corner velocity, the P-47s better instantaneous rate of turn, and smaller turning circle changes the outcome.  So I also question your conclusion about the high speed handling of the FW 190.  Everything I've ever seen says that the stick forces were generally light and not objectionable at high speeds.

Offline BnZs

  • Platinum Member
  • ******
  • Posts: 4207
Re: Me-109 turn to right widely said to be poor; any clues?
« Reply #59 on: April 04, 2009, 10:10:06 PM »
:lol carriage return warfare

Yeah...I think the next time I see a case of cranal-rectal inversion of this magnitude, I'm just going to pop a pill to keep my head from exploding and pass right on by...
"Crikey, sir. I'm looking forward to today. Up diddly up, down diddly down, whoops, poop, twiddly dee - decent scrap with the fiendish Red Baron - bit of a jolly old crash landing behind enemy lines - capture, torture, escape, and then back home in time for tea and medals."