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| IL-2 Sturmovik The famous combat flight simulator. |
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#21
07-03-2010, 11:17 PM
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I "just do it" in my own way, K_Freddie! With links and text...
I am amazed that you say that the Il-2 FW-190A is unlike what everyone says it is: Do you actually downthrottle to sustain tighter slow speed turns? And everyone says the Il-2 FW-190A high speed handling is great: It should not be so, at least after the FW-190A-4 variant, or before the FW-190D "Dora", I would think, if at all... And even the A-4, in high speed dive pull-outs, should be very poor with a lot of tail-down "sinking" on pull-out if you do not pull very gently... Gaston 
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#22
07-04-2010, 01:09 AM
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-Well you would be surprised how consistent front-line fighter pilots descriptions are, without most of them having ever gathered in one room to conspire to tell the exact same same story... Note at the end of my original post how both the British and Russian sources I linked observed the exact same thing: The lighter Me-109G diving and extending away from above, while the heavier FW-190A stayed low and "stayed" in the fight by turning horizontally against lightweight fighters...: http://forum.1cpublishing.eu/showthread.php?t=15392 I have read thousands of combat reports, and most of them make no sense at all if you don't accept that the FW-190A out-turns the Me-109G, and most other Western types also if it downthrottles, during low speed sustained turns... Surprisingly, side-by-side tests with unfamiliar test pilots are a lot more hit-and-miss than combat anecdotes, and the US Navy's Fw-190A tests in particular do little more than regurgitate what they assumed beforehand to be true... Plus the aircrafts they tested were badly out of tune in the crucial aileron adjustment, since they could not even detect the FW-190A's superior roll rate! This led to an official wartime rebuttal of this test by the British RAE, with a document sent to the US Navy indicating the F4U and FW-190A are in no way equal in roll rate, as the US Navy test claimed! In addition to roll rate, the ailerons are also a crucial part of the FW-190A's low-speed sustained turn performance: They are used to "catch" the stall's wing drop, and the turn then "rides" on the aileron, as one FW-190A pilot described it... Note I spent fifteen years researching these issues to create a full colour boardgame simulation based on the Avalon Hill's "Air Force" system: They may be just anecdotes, but I have found over fifteen years of research that they painted an infinitely more coherent picture than any math-based conclusion I ever read... http://forums.ubi.com/eve/forums/a/t...708#5031083708 Sadly, there is one mistake that is left in my game that I will likely never fix: Only the P-47D Razorback is depicted, but I assumed that the paddle-blade propeller made it a better-turning aircraft in sustained turns... It then occurred to me that from May of 1944 forward, the P-47D no longer seems to be competitive with the FW-190A in sustained level turns in the 600 combat reports I studied here: http://www.wwiiaircraftperformance.o...r-reports.html I assumed that it was the introduction of the fuel-heavier "Bubbletop" variant that made it somehow less maneuverable, which is why I limited my game Data Card to the Razorback variant... Maybe the different shape worsened the handling? That was my reasoning at any rate... But now I am having doubts: The Bubbletop variant barely started to be delivered in April of 1944, and the loss of maneuverability in sustained level turns is evident almost simultaneously in that period, when most P-47Ds would still be "Razorbacks"... This noticeable difference in sustained turn performance seemed to be because of something introduced earlier... It was this Luftwaffe assesment I saw later that increased my doubts: They tested a captured P-47D "Razorback" which, in addition to having the "handicap" of a narrow needletip-bladed prop, could not be run at full War Emergency Power... They only barely got up to "Military Power" on it, and it was sluggish compared to a P-51B in speed and especially in climb performance... Despite this, this was their surprising conclusion: A flat-out: "The P-47D out-turns our Bf-109G". (Source: "On Special missions: KG 200")The lack of qualification of course means sustained turning, since unsustained high-speed turns are usually accompanied by a turn radius figure, and are often of only 180° of duration for the radius... This sustained turn performance was puzzling to me for an underpowered P-47D running a needletip prop... It shouldn't have been if I had been logical in applying my "prop load traction loading the wing" theory... Only then did it strike me that the introduction of the Paddle-blade propeller on the P-47D started in January of 1944, requiring about two to four months to be really generalized: About the same timeline as when poorer sustained turns seems to be observed as a matter of course against the FW-190A... One P-47D pilot said of the Paddle-blade prop: "It was like having 3 or four hundred extra horsepower pulling"... A significant improvement in climb rate. On the FW-190A I knew a broader prop blade allowed it to sustain speed better when downthrottled "It gave more "bite" in the slow-speed turns", said one FW-190A Western ace pilot who used downthrottling in turns... So it should also be better on a P-47D... But then I never heard, in those 600 reports linked above, of a P-47D pilot downthrottling, except very briefly to avoid overruns: With such a heavy aircraft it just didn't seem right to downthrottle in sustained level turns I suppose... But at full power, if you have less power to begin with, and a needletip prop which is like 3-400 horsepower LESS, then you unwittingly sustain tighter slow-speed turns better because the prop disc is less loaded, which in turns means your wing is less loaded... In other words, the earlier P-47D is downthrottled for you from the start, hence early 1944 P-47D level turnfights that make for very interesting reading: The P-47D absolutely crushes the Me-109G in level left turns, gaining fully in 1 to 3 X 360° turns on average, while the P-51D can often take 15 minutes of continuous turning: 40+ full 360° turns, to do the same thing vs the very same Me-109Gs... Right turning is apparently not to the P-47D's advantage vs the Me-109G, but right turning is very rare as pilots find right turns unnatural if they are right-handed: The bank side maneuver required feels unnatural to the pilot, according to an Israeli pilot quoted in the show "dogfights". This seems to be true: Right-sided sustained turn fights are a fairly small minority in those 1200 reports... In any case, it does seem to follow my logic that early P-47Ds, if they are going to be run at full power anyway, will do tighter sustained turns if they have less power and less efficient prop thrust to ruin their wing's lift to begin with... I wish I had thought of this before I had "finalized" my game's P-47D... Gaston
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#23
07-04-2010, 07:38 AM
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It all amounts to which tactics to use at which speed/situation. From my experience the FW and ME109 have excellent slow speed characteristics, and on many occassions I have outturned other allied a/c by throttle variation. At high speed the LH turn favours the FW, but at low speed the FW's niche is the RH turn. This is where the propwash and engine torque pulls the nose up and left, enabling one to use full pitch and rudder to bring it around a lot quicker than other aircraft. This is a fine balance, but very workable. The FW is also excellent in the vertical, whether it's pulling out or up. It does wash a bit with lots of pitch, but this is very usefull as a deception. The 'washing' if used properly can enable the FW to change direction very quickly. Using a combination of the above, can make the FW a very dangerous foe for any a/c... Oh!.. forgot to mention the roll rate  
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#24
07-04-2010, 10:42 AM
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It is an interesting picture: The high speed turn preference to left is correct, as is the low-speed preference to right! (Though I had, perhaps wrongly, assumed that at low speed this reversal of preference was due to the deployment of flaps in low speed fighting: See Eric Brown's description of the landing configuration stall: The stall wing drop direction is reversed from a harsh left to a gentler right wing drop with flaps down: The side of the wing drop is the better turning side)
According to Closterman, FW-190As did not initially use their flaps to turn in combat, but later in the war they did, and it did tighten their turning ability... At high-speed, use of flaps is very costly in speeds because the engine does not accelerate enough to compensate, at these speeds, for the extra drag, in addition to turning. Combining downthrottling and flaps should, in real-life, allow out-turning at low speeds, in sustained turns, any major later war Western Front Allied fighter, with only the Spitfire being a question mark and maybe the P-38 at extremely low speeds. The FW-190A Western ace stated, despite his exclusive turning tactic: "I feared no other fighter in my FW-190A-8" Turning, sustained or not, above 250 MPH MIGHT be about equal or better to the Me-109G if flying an early short-nose FW-190A-3/4, but DEFINITELY not for any later Anton variant (see A-5 test vs P-47: http://img105.imageshack.us/img105/3950/pag20pl.jpg ). These later variants above 250 MPH IAS should be worse in turns and pull-outs than most other fighters. So for late war Antons, the Il-2 picture at high speed is wrong: The Me-109G should be superior, as it should be superior to the FW-190A's vertical maneuvering except maybe for the first zoom from a very high speed. The Me-109G's absolute superiority in climb rate is what impressed the Soviets the most, and this made it an essential complement to the Anton on the Eastern Front at least. Interesting note: Starting the turn fight at high speed, hoping to decelerate into the better lower speed while turning, is a dangerous idea in a Fw-190A... Maybe especially so for later longer-nose Antons: As the Fw-190A decelerates into its more favorable lower speed turn speed region (around 220 knots-250 MPH IAS) it abruptly changes pitch, which has to be compensated by the pilot instantly by pushing forward on the stick... Or it will stall: This is why the FW-190A Western ace described downthrottling long PRIOR to the merge: Decelerating from faster into lower speed while turning was risky... E. Brown also mentions this abrupt change in pitch, but did not find it dangerous on a short-nose Anton. It may have been worse on later Antons, as a few combat anecdotes seem to indicate... The Me-109G was better in the vertical, but still inferior in zoom or dives to US fighters! The Me-109G was better off downthrottling into very slow flat turns at 160 MPH against US fighters. The spiral climb might have helped, but it was very rarely used, so it must not have been convenient to use... Downward spirals are a bad tactic for all chased fighters... The firepower and strenght of the Fw-190A made countering dive and zoom tactics by turning to face head-to-head into the attack worthwhile. You say throttle variations, but once committed to lower speed turn fights, there is usually no upthrottling except maybe for catching up to a zoomer or a diver... I don't think it is likely the FW-190A liked abrupt pitch transitions... You had to work the stick gently... I will post later an English test of the FW-190D-9 that shows it to have far inferior maneuverability to the Anton, to the point of nullifying its climb and speed advantages over the Anton in the opinion of the tester... Thanks for your picture of the FW-190A's handling in Il-2: It could be reasonably accurate for early shorter-nose FW-190A-3/4s... Gaston
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#25
07-04-2010, 12:39 PM
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I was intrigued by your description of the Anton as a low speed turner, so I decided to try some rough tests in Il2 to see if this supported the idea.
They are by no means perfect, but I did my best to keep conditions the same throughout the test and the results are averages of the good turns (ie if I stalled the aircraft or found myself more than 100m above or below my starting altitude I discarded the results). I used the Fw109A-5 and the Spitfire LF MkIXc for the tests. Technique used was a flat turn, using rudder where needed to keep the aircraft's nose up, and just trying to see the tightest turn that I could produce, regardless of speed. Full throttle @ 500m (left turn) MkIX 17.1 sec A-5 22.4 sec 80% throttle @ 500m (left turn) MkIX 16.0 sec A-5 18.7sec As you can see, while the Spitfire only gains 1.1 sec by downthrottling, the A-5 gains 3.7 sec, halving the gap from 5.3 sec to 2.7 sec, and the difference between a down-throttled A5 and a full throttle MkIX is only 1.6 sec. The A-5 turns on a similar radius but at a lower speed, and is noticeably easier to stall, especially if you try to change direction once you have slowed down in the turn. Since both aircraft have props that rotate to the right, I didn't try repeating the tests with right turns.
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#26
07-04-2010, 02:37 PM
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Last edited by Ernst; 07-04-2010 at 02:55 PM.
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#27
07-04-2010, 02:59 PM
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Two questions, David603:
Were you trying to do a minimum-radius turn, or a best-rate turn? The results would be different. In combat, rate is usually more important than radius. Are these sustained turn rates? Unless you can maintain speed, altitude and turn rate continuously, the results may be misleading. Even a loss of height of a few meters can make a noticable difference to results. EDIT --- I've been doing a bit of experimenting, using my prototype autopilot application (see http://forums.ubi.com/eve/forums/a/t...097#4121016097), and though I need to investigate further, I find it very difficult to believe a Fw 190 A5 will do a 360 degree sustained turn in 18.7 seconds, regardless of throttle settings. IL-2 compare suggests the best turn time will be around 24s, which is much more consistent with the results I'm getting at full throttle, and trying to turn at that sort of rate at 80 % throttle results in a rapid decay in airspeed. My autopilot is struggling to hold a smooth turn in these conditions (it was never designed to do this), but I'd be surprised if a human pilot could do much better - the plane is right on the edge of the stall. As Ernst says, we need to see a track. Last edited by AndyJWest; 07-04-2010 at 09:24 PM.
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#28
07-05-2010, 01:06 AM
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The Spitfire Mk IX at full throttle is still 1.6 seconds faster than a FW-190A-5 at 80% throttle: This could be plausible if the FW-190A-5 does not use an optimal flap setting: The flap setting was critical to low-speed performance.
The Spitfire IX could not use a combat flap setting: 2 position only... Soviet tests of a FW-190A-4 did show about 19 seconds in turn times, but it was displayed as 19-23 seconds, implying the difference in side of the turn(?). Note the best Soviet Gustav time for that test, for a clean Me-109G-2, WAS 22 seconds, so right there you have the FW-190A out-turning the Me-109G to one side at least... Me-109F was 20 seconds. Note that the longer-nose A-5 was said by the Soviets to shave a second off these figures, which would give about 18-22 seconds. I assume these real-life tests were all done at full power without flaps... At partial power it could be all these aircrafts do not do much better in sustained turn TIME, but much better in RADIUS, which gives some advantage in sight lead also... A FW-190A-8 in sustained low-speed level turns, flaps down, at 70% power(?), can gain nearly 180° per 360° on a P-51D at full power riding on the edge of a stall: If flaps up full power for the P-51D means 23-24 seconds, then the FW-190A-8 with the broad-blade prop could be as low as 16-17 seconds to one side (it was the right side with flaps down), to reverse a tail position in 2.? X 360° turns... The A-8 was said to be better than all previous FW-190As in low-speed maneuverability, especially with the broad-blade prop. Of note is that the FW-190A riding on the edge of a stall requires the use of the ailerons to catch the stall's wing drop: At low speeds this favoured the choice of the longest chord of three different types of ailerons that could be used. The FW-190A Western ace in AH's forum described adding "spacers" to the hinges of his longest-chord aileron choice, to increase low-speed wing-drop "catch" performance further, this of course at the expense of aileron leverage and performance at high speed... This choice of his was specifically described by him as being exclusively aimed at low-speed turn performance... These aileron hinge modifications could explain the out-of-the-ordinary low-speed turn performance he mentions for his P-51D shootdown: 2.? X 360 to reverse a tail position on the deck, the P-51D almost stalling in front of him... Not clear if the aileron hinge extensions were a field modification, or availabe as a kit... Interesting tests for the in-game figures... Thanks! Gaston
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#29
07-05-2010, 02:04 AM
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And as for 'catching the stall's wing drop' with aileron, this is nonsense if you are talking about a sustained turn (along with airspeed, turn rate and altitude, AoA must be constant so either the wing is stalled or it isn't), and dubious as a means to recover from a stall anyway. If a wing is stalled, down aileron is going to make it worse. Even with the luxury of an autopilot, and no worries about structural/engine failure, fatigue from G forces, instrumentation errors and the rest, practical experience with the few tests I've run tells me that any measurements of turn rates need to be taken with some scepticism. Out of curiosity, does anyone actually know how turn rate was measured? The compass would be useless, and I'm not sure a gyro would be much better - they tended to tumble with extreme manouvering.
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#30
07-05-2010, 05:24 AM
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First, the force vector of the prop points inwards, due to the angle of attack the aircraft uses in a turn, it pulls the aircraft to the inside and therefore more power lowers the wingloading and improves turning. Second, more power increases the airflow over the wing, thus increasing the wings lifting ability and therefore improves turning. Third, any effect the prop forces might have on turning, will be canceled out by the elevator, which itself only has a minimal impact on drag. And finally, in a sustained turn, you need speed to do the turning, more speed means more g's, means more turnrate. If you reduce thrust, you lose speed and won't be able to sustain a better turn. --- The same thing got posted on the ubi-board, and the topic was locked immediately. Take it as a measure for the quality of the original post. It's complete and utter nonsense.
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