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FM/DM threads Everything about FM/DM in CoD |
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#31
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Not having your realism settings set accordingly can initiate unrealistic performance as you describe. Here is a pic of the realism settings FYI - check your Engine settings and Atomosphere and Handling. S! |
#32
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The real 109E could do sustained turns in 18.92 secs at 1.3ata at SL, we have the 1.35ata version so probably it can be marginally better than that.. anyway, I did a quick test and got about that much, so I don't there's something wrong there.
I don't know how fast Hurris and Spits turn though. They should be better, but by how much? If they would do a sustained turn in 11-12 secs I'd say something is definietely stinking (that's a biplane only zone), but 15-16 secs would sound about right.
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Il-2Bugtracker: Feature #200: Missing 100 octane subtypes of Bf 109E and Bf 110C http://www.il2bugtracker.com/issues/200 Il-2Bugtracker: Bug #415: Spitfire Mk I, Ia, and Mk II: Stability and Control http://www.il2bugtracker.com/issues/415 Kurfürst - Your resource site on Bf 109 performance! http://kurfurst.org ![]() |
#33
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Sorry Kurfurst but you are wrong about the spit elevators, they were sensitive yes but can in no way way be classed as ultra sensitive. I am a real world aerobatic pilot generally flying a Pitts special, and have flown many aerobatic types. The elevator on these aircraft IS sensitive, much much more so than the Spit. The Spitfire that went into service was and always has, been described as having well balanced controls (a twitch elevator would not accord this distinction!).
It is a well known fact that the British aircraft types were much more forgiving than the German equivalents, a factor in itself in the supremacy of the Spitfire over the ME109 during the Battle of Britain. You had 'green' pilots on both sides, but the Spitfire was markedly easier to fly for those pilots allowing inexperienced pilots to get more out of the machine than was typical of the Germans. |
#34
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The Bf-109 is much more forgiving than any straight wing high aspect ratio design without LE slats. Think of the slats just like training wheels. An elliptical wing on the other hand exhibits very harsh stall characteristics because of its shape. Last edited by Crumpp; 05-04-2012 at 11:45 PM. |
#35
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Intel Q9550 @3.3ghz(OC), Asus rampage extreme MOBO, Nvidia GTX470 1.2Gb Vram, 8Gb DDR3 Ram, Win 7 64bit ultimate edition |
#36
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![]() ![]() ![]() No doubt Kurfurst will bring up the Spitfire V crashes described in Shacklady and Morgan...pp 160-161 (I think) Or he'll post the attached paper and claim that this proves how dangerous and unstable the Spitfire was because so many of them broke up in flight. So, to save all our time from his predictable arguments here's what Supermarine Chief Test pilot Jeffrey Quill had to say about the "dangerously unstable" Spitfire (Spitfire:A Test Pilot's Story. John Murray, 1983): "In a high-performance fighter, lack of stability can be exceedingly dangerous in the course of manoeuvring at high speeds...Therefore, in aeroplanes such as the Spitfire, which were entirely manually controlled, any inherent instability was unacceptable and potentially dangerous.... There were other factors which affected the aerodynamics of the stability of the Spitfire. For example the aerodynamic characteristics of the elevator itself (as opposed to the fixed tailplane) also had a major influence on stability and at Supermarine we exploited this and increased the stability margins as we moved from one mark of Spitfire to another. (229-230) In general configuration the Mk I and Mk II production aeroplanes were almost identical to the prototype and so there was no problem with their stability. (231-232) The Mk III Spitfire did not go into production, but the success of the bobweight experiment in curing its instability...opened up the possibility of its use for later marks of Spitfire....which was just as well as we had to...respond to a nasty situation which developed in 1942. The Mk V aircraft was...in full service with Fighter Command and,...a fair amount of additional operational equipment had gradually crept into the aircraft, most of it stowed within the fuselage. The aftmost acceptable position for the aircraft's centre of gravity had been fixed in the normal course of flight testing by the firm and by the A & AEE....Any rearward movement of the centre of gravity in service, for whatever reason, would begin to destabilise the aircraft. Therefore, for each sub-variant of the Mk V detailed instructions for the correct loading of the aircraft were issued to squadrons....However the importance of these loading instructions was not generally appreciated in squadrons and in the daily round of operational activity they tended to be disregarded." (pages 232-233 -Quill goes on to describe 65 Sqn's Spitfire Vbs which were found to be dangerously unstable) There was thus a real chance that, as of that moment, in almost every squadron in the Command Spitfires were flying in a dangerous state of instability....Up to that time there had been a distressing and increasing incidence of total structural failure of Spitfires in the air, which was causing great concern in the MAP and especially at Supermarine. (pages234-235) ....our aerodynamicists at Hursley Park thought that an even more effective answer could be obtained by enlarging the horn balance of the standard elevator and this we did in stages. The effect was astonishing. At last a way had been found to improve the basic stability of the aeroplane, thus giving more flexibility in centre of gravity movement, without our having resource to any enlargement of the fixed tail surfaces....The enlarged horn balance of the elevator produced a slightly unpleasant 'feel' of the aeroplane at low speeds...This effect was trivial by comparison with the gains in stability margins." (p 237) Once the bobweights had been introduced and, in later marks, the modified mass balances on the elevators...it was statistically established that, as soon as the longitudinal stability of the Spitfire was thus brought under control, the problem of the unexplained breakings-up of aircraft in mid-air,...'softly and suddenly vanished away'. (page 238 ) Note the comments that stability margins increased over the course of Spitfire production; with the introduction of the Griffon engined Spitfires, and especially the five bladed propellers of the 65 series the size of the tail surfaces were increased to help cope with the bigger blade area and extended nose - there were some marginal instability problems, but not enough to make the aircraft dangerous. There were problems with the early Spitfire F. Mk 21's control characteristics, but these were ironed out with further developments in the elevator balance weights and configuration. The Mk Vs breaking up in flight were badly loaded with extra equipment in squadron service, with their cg pushed too far back, thus they were dangerously unstable, but this was not an inherent problem with the airframe. No doubt Crumpp will try to claim that with his vast aviation experience he knows better than Jeffrey Quill and there'll be other smokescreens by another Spitfirephobe who has posted here but the fact is that All claims about the Spitfire being inherently dangerously unstable are quite false and not worth bothering with. Last edited by NZtyphoon; 05-05-2012 at 01:58 AM. |
#37
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And here's what Alex Henshaw, Chief Test Pilot at Castle Bromwich, says about the flight characteristics: Spitfire demo flights:
"...The Spitfire would then continue with a series of loops and half-rolls to gain height over the airfield to between 4,000 and 5,000ft. Depending on the precise position of the aircraft in relation to the airfield, the usual procedure was to dive to 450-470 mph in front of the flight shed and then pull out and complete an upward roll to the left, one to the right and a half-roll left. This manoeuvre might be repeated or continued with a vertical dive with aileron turns...Considering how often this was demonstrated with all marks of Spitfires I am surprised that it should ever be suspected that wings might suffer structural failure in such a situation when excessive aileron loads were used in high-speed dives. From the Mk I Spitfire up until the Mk 21 the Vne was set by the Supermarine technical department at 470 mph IAS at a height assumed to be between 5,000 and 10,000 feet....At no time did the Supermarine test pilots reduce the Vne from 470 mph to 450 mph....If ever any doubts existed within our own test pilots as to the structural risks of diving the Spitfire they were dispelled when reports were received from combat units to the effect that some of their pilots complained of excessive engine revs when diving under extreme conditions....The basic pitch setting of the de Havilland propeller was set to give 3,000 rpm at 9lb boost on take-off, and would remain in the constant speed range up to full power and not exceed 3,000 rpm up to its Vne of 470 mph...it was decided to investigate the problem to its limits. A standard Mk V without calibrated instruments or modifications was taken up to 37,000 ft. A maximum speed run at full power with engine revs at 3,000 was carried out for 2 minutes before peeling off with a half-roll to dive down to near ground level. Up to the Vne of 470 mph the propeller constant speeded with engine revs at 3,000, and then as the speed increased the propeller came up against its basic pitch setting stop and engine revs climbed rapidly. The ASI indicated what might be assumed to be some degree of accuracy within the normal range, but as the speed progressed beyond the these limits the needle climbed so far into the region beyond the 450 mark that it was obvious that no further notice should be taken of it. We were not certain that the machine had in fact reached its terminal velocity point...it was decide to carry out another dive with greater concentration on the rev counter....This final dive proved two factors. With the single-stage blower Merlin, the Spitfire could not be dived faster, and at 3,700-3,800 rpm in those conditions the basic pitch setting should be readjusted." (Aeroplane Monthly September 1995, 55-56) Yep the Spitfire was so dangerously unstable that Henshaw flew it like a maniac and crashed and died several times. Last edited by NZtyphoon; 05-05-2012 at 01:56 AM. |
#38
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Quill on the prototype: "The A&AEE pilots remarked also that the elevator was too light and too powerful and they recommended reducing the gear ratio between the elevator and the control column. I suspected at the time, and later with more experience and understanding of the problem I became quite convinced that they were wrong in blaming the elevator for being too light. This was much too simplistic a conclusion. The aeroplane was on the borderline of instability and making a heavier elevator, or even a smaller one, would have been no solution." cf his comments about further development increasing the stability margins. (Spitfire:ATPS p. 231) Last edited by NZtyphoon; 05-05-2012 at 01:59 AM. |
#39
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This was a security measure installed by supermarine because they were aware of the problem of the elliptical wing that you just mentioned. When you read raf pilot accounts they repeatedly mention that they got buffeting shudder on the brick of a stall warning them about an imminent stall. This situation occured when the inner section stalled but not the outer section where the ailerons were, allowing the spit to be still controllable around the roll axis. Of course cranking the wing also meant to deteriorate the aerodynamical properties of the elliptical wing so that it was less optimal aerodynamic wise. The induced drag was hence bigger than with an uncranked wing. As the advantage of the elliptical wing was later found to be minimal with respect to a trapezoid wing it was abandonned in aviation as the disadvantages in terms of production outweighted its minimal benefits. That's why I definitely think that the elliptical form in itself had nothing to do with the great performance. What supermarine however probably managed to pull off was to design a wing with a large surface which however created more drag but allowed for high lift which was still light weight and in particular very thin. Last edited by 41Sqn_Stormcrow; 05-05-2012 at 08:28 AM. |
#40
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[QUOTE=BlackbusheFlyer;419116]Sorry Kurfurst but you are wrong about the spit elevators, they were sensitive yes but can in no way way be classed as ultra sensitive. I am a real world aerobatic pilot generally flying a Pitts special, and have flown many aerobatic types. The elevator on these aircraft IS sensitive, much much more so than the Spit. The Spitfire that went into service was and always has, been described as having well balanced controls (a twitch elevator would not accord this distinction!).
I would have respectfully disagree with you assessment, particularly about control harmony. It was a weak part of Spitfire control, as the elevator indeed touchy, while. One Spitfire pilot described the phenomenon as 'touching the elevator with a light fingertip, while arm-wrestling the ailerons'. I would suggest you to study the Spitfire II pilot notes on control aspects, basically they all about instability in pitch and poor control harmony, here: http://forum.1cpublishing.eu/showpos...17&postcount=4 It particularly challenging thing to do when flying near the stall, NACA for example found that the stall boundary on the controls was very small, just 3/4 inch of stick movement having been found between the first sign of stall and actual stall. This was offset party of course by ample stall warnings and otherwise good stall characteristics, but it took an experienced pilot to fly the aircraft to its limits. Quote:
http://kurfurst.org/Tactical_trials/...ls/Morgan.html Quote:
__________________
Il-2Bugtracker: Feature #200: Missing 100 octane subtypes of Bf 109E and Bf 110C http://www.il2bugtracker.com/issues/200 Il-2Bugtracker: Bug #415: Spitfire Mk I, Ia, and Mk II: Stability and Control http://www.il2bugtracker.com/issues/415 Kurfürst - Your resource site on Bf 109 performance! http://kurfurst.org ![]() |
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