Bf-109F-4 and a bleak time for RAF

Discussion in 'Old Threads' started by Chingachgook, Nov 27, 2006.

  1. Chingachgook

    Chingachgook Banned

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  2. Sarge714

    Sarge714 New Member

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    Looks like the big advantage of the Fw190 over the Bf109 is a lighter stick force giving it the ability to pull more g's at high speed. The Fw190 actually has a turn advantage over most fighters above the high 200's mph.

    A big question is did the German pilots have some type of g-suit to help take advantage of the ability to pull higher g's?

    Don't know of any sims yet to correctly model things correctly. Fingers crossed JSBSim someday becomes the defacto standard FM used by all mfg's so we can correctly model the aircraft and see what really they were like to fly air combat in.
     
  3. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    No...
     
  4. bomber

    bomber Banned

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  5. Chingachgook

    Chingachgook Banned

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  6. delcyros

    delcyros Well-Known Member

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    I must admit that the sources from
    Beim-Zeugmeister: Seite 12 - Firmendaten Messerschmitt, Teil 3

    show original documents which proove the given 670 Km/h WEP figure ("Start- und Notleistung") as beeing practically experienced ("erflogen"). The note that it was done at exactly 6300m points that this was the utmost top speed. This powersetting cannot be used for more than 2-3 minutes. It serves well for rapid climbs, however. Keep also an eyeon the avaiability of the WEP setting. The author confirms that the use of WEP on the DB 601E was forbidden early but later allowed. He was not able to nattow the important timeframe down as docs are missing.
    635 Km/h is the usual and sustainable 100% powersetting ("Steig- und Kampfleistung") rating at 6000m (at 6300m we should expect a slightly faster figure, around 640 Km/h).
    Pay attention to the time to altitude figures (at 100%):
    0 to 3000m (9930 ft.): 156 sec. (2.6 min)
    0 to 6000m (19860 ft.): 366 sec. (6.1 min)
    0 to 10000m (33100 ft.): 822 sec. (13.2 min)
     
  7. Chingachgook

    Chingachgook Banned

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  8. Hop

    Hop Member

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    Whether the speeds could be reliably attained in combat depends on a couple of things about the quoted 416 mph figure.

    First, is it corrected for compressibility and atmospheric conditions?

    Secondly, what condition was the aircraft in? Polishing alone could increase speed by a fairly large amount, filling in gaps and changing external features could make a very large difference.

    As an example, take the Spitfire V.

    First production standard aircraft tested was W3134.

    It had a maximum speed of 371 mph at 20,100ft without a snowguard, and 364.5 with a snowguard.

    The Royal Aircraft Establishment later tested a Spitfire V to see what effect minor alterations would have on speed. They found:

    Changing from fishtail to ejector exhaust stubbs increased speed by 7 mph (W3134 probably had fishtail exhausts)

    Removing the carb ice guard raised speed by 8 mph.

    Fitting a fairing to the rear view mirror increased speed by 3 mph

    Cutting the ejection chutes flush with the wing increased speed by 1 mph

    Sealing cracks, rubbing down and polishing the leading edge increased speed by 6 mph

    Waxing the rest of the plane increased speed by 3 mph.

    I don't know the surface quality of W3134, so it's not safe to apply the last 2 mods to it, but just changing the exhaust stubbs, fairing the mirror and cutting the ejector chutes down would increased W3134s speed to 382 mph. The RAE test, which started out with a Spitfire V in 1943 doing 357 mph, ended up with it doing 385.5 mph.

    So, 371 mph probably represents a typical squadron service Spitfire Vb. 385 mph represents one with a little cleaning up.
     
  9. Chingachgook

    Chingachgook Banned

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  10. pbfoot

    pbfoot Active Member

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    i mentioned this in another post but the single greatest factor in increasing speed aside from waxing is the simple removing the dirt and dust from inside the aircraft
     
  11. Sarge714

    Sarge714 New Member

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    JSBSim: Open Source Flight Dynamics Model in C++

    It's at least an order of magnitude above any of the current retail FM's. It's structured right and flexable/adaptable. Necessary items for WW2 flight modeling.
     
  12. delcyros

    delcyros Well-Known Member

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    The Bf-109F model already is the aerodynamically cleanest variant of the 109 family. The testmodel was factory new but nothing special on it other than that the engine performed the power it was designed for (unlike the DB 601 of the british test 109F2). I conclude that the 416 mph may be achieved in combat in case it was allowed to use this powersetting ("Start- und Notleistung") in combat. Top speed was flown on a measured mile with Askania Theodolits and recalculated for atmosspheric circumstances as it was typical by that time.
     
  13. bomber

    bomber Banned

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    Try Targetware and see what you think... ?
     
  14. Twitch

    Twitch Member

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    As Hop points out there are many factors to consider in fiddling with top speed of various aricraft. A 2-3 minute WEP use is dubious at best to categorically state that 416 MPH was a true usable velocity to quote as an everyday speed to expect.

    Certainly no manuscript attributes more than 390 as a top end for the F-4 even Heinz Nowarra in Germany who had all the records of Messerschmitt to draw upon in his 1964 book The Messerschmitt 109.


    Rechlin performance evaluations for other aircraft state some higher than standard top speeds observed also. The Do 335 is another that flew better at Rechlin than it was observed to do in final form for Luftwaffe service.

    A speed advantage is not an end-all decides-all factor in combat either. Every time a faster plane manuevered it bled speed away so that in an engagement with contemporaries the F-4 would have had no stand-out advantage. It climb is initally 4,350 FPM but that's not consistant through all altitudes either.

    Contemporary Spits had equal armor and far greater firepower unless we look at the F-4/R-1 with "gondola" guns which degraded both speed an maneuverability performance through additional weight and drag.

    Part of the flaw of performance comparisons is that rarely are two opponents at the optimum altitude in near identically performing crates anyway. Where a low altitude can give one ship an advantage it is lost at a higher level. More rare still is the scenario where a plane, with even a 50MPH speed advantage, could pull away from a trailing opponent and not expect to be shot all to hell. Nothing in WW 2 could outrun cannon and machine gun rounds! Unless the lead plane had a very large advantage of distance he would not be able to flat outrun his pursuer. The trailing plane certainly would be able to set up a gun solution for a kill as the faster lead plane poured on the coal.

    Speed by itself is not a decisive factor unless we compare jet with piston of 150-200MPH advantage.

    The tuning of engines is not a static thing. If we look at the Tempests on Diver duty intercepting V-1s we see that these planes were retuned from factory specs to bring the power band in a low altitudes. A chat with a crew chief from any service will confirm the fact that the engines could be hopped up or detuned as needed for short power bursts or longevity.

    I can flatly state that at no time was Johnnie Johnson, Peter Brothers, Bob Tuck or any RAF ace I've talked to ever "outrun" by 109s or 190s of any model. P-51s didn't run away from 109s or 190s either even with a top speed advantage. Speed held no decisive advantage in head on firing passes either.

    Aircraft on all sides had varying performance within the same squadron due to many factors noticable by pilots finding it hard to keep up with their mates even in cruise formation. Every engine and plane had use to assorted degree rendering some of them less than factory fresh in the performance area at given times.

    Top speed is a characterizarion of two dimensional performance in a 3 dimensional world of combat. When an opponenent encountered an enemy with good horizontal performance he took the fight vertical to his plane's advantage. Even diving away with the use of a speed advantage is does nothing to defeat and destroy an enemy.

    I guess the real question is do you want to run away or fight?
     
  15. Smokey

    Smokey Member

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    But there were some examples of outdated piston engine fighters, weren't there? Like the I 16 versus the Bf109F and G and the Zero against the Corsair, P 38, Mustang and late Spitfires?
     
  16. Chingachgook

    Chingachgook Banned

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  17. delcyros

    delcyros Well-Known Member

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    Hi Twitch, I always use to enjoi our disussions!


    Probably. As pointed out above, speed depends on more issues. Individual state of airframe and engine beeing the most important. German planes always suffered from a briefer allowed use of WEP than -let´s say- US planes.
    2-3 min. are very worthy for rapid climbs and stand up acceleration. That´s what opens the distance in run and that what´s closes the distance in a chase, both very credible advantages for the F4.
    However, note that the WEP was forbidden to use by special maintenance orders for a certain timeframe (reasons for this are unknown).

    That´s wrong. The documents given in the source are primary sources, Nowarra had secondary docs on hand and never dealt with the sources itself. And as the author points out, german primary sources do consistently show a 670 Km/h max. WEP /6700m speed figure for 1942-43. He knows more than just a few.
    Even if You decide to neglect the WEP, the max. speed (30+ minutes sustainable, unlike those of the Spits!) at "Steig- und Kampfleistung"- powersetting for 6000m is consitently 635 Km/h (394 mp/h) at 6000m and more like ~400 mp/h at 6700m respectively. That is still superior and unlike other planes with boost fairly sustainable.

    In comparison to what? Rechlin -except from Karlshagen maybe- had the most decent speed measuring devices avaiable. Perhaps other measurements were less sensitive? The example with the Do-335 is misleading as You are comparing two unidividual planes. The Do-335 AV-prototypes at Rechlin were flown without guns and ammo unlike those to be used by Luftwaffe Ekdo. This has been noted on the -335 testcharts. None such notes occur in case of the 109F4 tests (similar testresults are also reported from Augsburg with a 665 Km/h max. speed using WEP at 6800m).
    Initial climb is given for "Steig- und Kampfleistungs"-powersetting. At WEP its more like 4500-4650 fpm, gradually reducing with altitude.
    Tell that the red republicans at Spain! Or the french in 1940. Or the japanese in 1944. A speed advantage of at least 20, better 40 mp/h is comfortable for ww2 fighters. And it´s getting more important once pilots adopt for the energy thinking.
     
  18. Chingachgook

    Chingachgook Banned

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  19. Glider

    Glider Well-Known Member

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    I have read this thread with nterest but at the end of the day I have never read or heard about any Allied Pilot in a MkV who felt that he was at a disadvantage against a 109F. I am not saying that the Spit had clear superiority, but that they were an even match with victory down to the best led units and or tactical position.

    I do not believe that 416 was achieved in regular combat in a 109F. If it had the SpitV would have suffered the sort of casualties that the did against the FW190, which was truly capable of 410 in normal combat conditions.

    I do agree that if a plane had a speed advantage of 20 to 30MPH over an enemy aircraft then that had a considerable advantage which would have been noticed by the opponent. As mentioned above, the RAF to the best of my knowledge didn't consider the SpitV to be outclassed by the 109F so any additional performance of the 109F must have been limited.

    An obervation about the filters fitted to the Spit in the desert, which certainly had an impact on the performance. The RAF didn't fit them for the fun of it and I was wondering what the Germans did to deal with the problem of the sand. If anyone can help with this it would be appreciated as its something that has always interested me.
     
  20. Hop

    Hop Member

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    Do you have a source for that? There was an extensive discussion on another board, with the author of the site that published the documents on the F4 test, and nobody was able to offer proof either way about whether the figures were adjusted for compressibility.

    From what I remember of the discussion, there were no other tests giving similar figures.
     
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