9 Tracks and a Paradox

Discussion in 'Warbirds International' started by squirl, Dec 15, 2004.

  1. -exec-

    -exec- FH Consultant

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    mah, you won't tell red wine from white :D
     
  2. RolandGarros

    RolandGarros Well-Known Member

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    Dont bring it into combat with full fuel aboard. I scored a triple in it last night (2 x spit5b + 1 x i-16-28) after rolling with 20% & landing with about 10%. Still a great turnfighter but heavily penalized by the fuel rule (which doesnt hurt short range fighters like the polikarpovs nearly as much)
     
  3. Glas

    Glas Well-Known Member

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    Personally, if I had built up a streak large enough to choose my fuel, I wouldnt take the Zero.

    Well, at least not if I wanted to preserve my streak ;)
     
  4. gryphon

    gryphon Well-Known Member

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    bomber streek conts so go bomb a few stratigic targets get streek and park that buff :). did that on gold and ki61 with 10-20% flew quite nicely.
     
  5. squirl

    squirl Well-Known Member

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    Centrifugal Force Divided by Centripetal Force

    @ the A6M issue.

    Keep in mind that even with 100% fuel, an A6M3 has a weight of only 5900 lbs.
    This provides a wing loading of 25.4 lbs./sq. ft.

    An empty Spitfire IX has a wing loading of 23.3 lbs./sq. ft. At 100% fuel, a Spitfire IX has a wing loading of 30.6 lbs./sq. ft.

    These data prove that the A6M should be an excellent dogfighter; even at 100% fuel.

    @ the Ki-61 turn.

    -Exec-, a 75 degree bank angle is the only bank condition that can result in a steady 360-degree turn done in 16 seconds at 206 mph.

    The fact that the equation says a plane can turn 360 degrees in one second is irrelevant. Is the formula for momentum invalid if it states it is possible to reverse direction near the speed of light? No. An almost infinite amount of G-forces would accompany that condition. The same applies to the formula for turning. A plane could turn 360 degrees in one second if it could sustain the G-forces and lift required. The truth, however, is that a plane cannot do that. It follows then, that if reasonable input is put into the formula, then reasonable data will come out. A 75 degree bank is reasonable. Putting unreasonable data into that formula will not disprove anything.

    The formula implies that a Boeing 747 and a P-47 will have the same turn radius and rate of turn if their airspeeds and bank angles are the same. What distinguishes one plane's turning ability from another's is the ability to maintain those numbers within the formula.

    Once again we come back to wings. I have broken the complex nature of wings down into the most basic semantics many times, but it seems another run-through is needed.

    -Centrifugal force is generated in a turn.
    -Gravity always acts on a plane.
    -In a turn, a plane must always produce lift to counter both centrifugal force and gravity.

    -Centrifugal force increases with airspeed, turn rate and/or mass.
    -Lift must increase to counter additional centrifugal force.

    -Having wings that produce lift are therefore desirable to counter centrifugal force, but lift is only one part.
    -The centrifugal force is derived from the mass of the plane.
    -The greater the mass of the plane, the more centrifugal force exists to counter the lift from the wings.

    It can therefore be concluded that:
    -A plane with more mass proportional to lift will produce more centrifugal force, making the process of turning for that aircraft proportionally much more difficult.

    This plane has two options:
    -Reduce rate of turn so the centrifugal force does not become too great or:
    -Stall

    The basic formula for the indicator of this ability is wing loading (mass of plane/wing area). This formula does not always hold true, however. The Spitfire has a wing that "cheats"; it has a large area but does not produce very much lift (low thickness to chord ratio). A much better representation is this formula: (mass of plane/lift produced by wings). This formula is the most raw form of this sort of physics: it is the quotient of the key factor of centrifugal force divided by the key factor in centripetal force. The lower this ratio is (a higher denominator) , the more amount of lift is available to counter the centrifugal force, meaning that the plane can turn without losing turn radius to centrifugal force.

    In summary, the formula for the turning ability of a plane is: (Centrifugal Force)/(Centripetal Force)

    The lower the ratio, the better the turner.
     
  6. squirl

    squirl Well-Known Member

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    Spitfire
    [​IMG]
    Ki-61
    [​IMG]
    The Ki-61 picture is of a model, but it is built to scale nonetheless.

    In the Spitfire photo, the Spitfire's left wing is prominent. One can easily see the thin wing that I described. The Ki-61, even though it is a model, has a thicker airfoil.

    These characteristics of the designs culminate in the concepts I described in my last post.

    Using this information, I have reached these conclusions long ago:
    -The Ki-61 has a lower centrifugal force/centripetal force ratio than the Spitfire IX.
    -The Ki-61 should turn better than the Spitfire IX.
    -better turn time
    -better turn radius

    If the Ki-61 can turn 360 degrees in 16 seconds at 206 mph, then the time taken by the Spitfire IX in the same conditions can be expressed as follows:
    Spitfire IX turn time >16 seconds.

    -Exec-, I have broken down the concepts into the most practical steps of explanation. The facts show that the Ki-61 should turn better than the Spitfire IX. If you cannot understand each individual concept and add them all up into the grand scheme of aerodynamics, then you are lost to all reasoning in this subject.
     
  7. -exec-

    -exec- FH Consultant

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    Re: Centrifugal Force Divided by Centripetal Force

    can you prove that sustained turning with 75° bank will take EXACTLY 16s per 360°?
    that the point we are talking all this long flame.

    you take 16s from e-loosing 90° bank maneuver from j-aircraft.com and your are trying to assign these 16s to sustained turn.

    it won't go, that's what i tell you.

    reasonable? we are talking about exact numbers, therefore give me exact limit for banks reasonable before it and senseless after that limit.
    heh. 90°senseless, 89°senseless, 88°senseless,....75°reasonable.
    where is the boundary?

    in fact this formula can be implemented in only in the direction from speed/time toward bank. that IS reasonable. reversing this formula from speed/bank toward time IS NOT reasonable. that's all.

    1942 airplane cannot maintain 313km/h in best-time sustained turn. some of 1944 can maintain it.
    you are free to disprove that.

    centrifugal force = centripetal force.
    (Centrifugal Force)/(Centripetal Force) = 1.

    so i'm stuck with this point and cannot go any further:

    PROVE THIS:
    STATEMENT 1 (DATA FROM J-AIRCRAFT)
    WE HAVE MANEUVER-L
    PLANE = KI-61-IB
    ENTRY SPEED = 313KM/H
    BANK = 90°
    AT LEAST 1 TURN MADE = 360. ONLY FIRST TURN IS TIME-STUDIED.
    FINAL SPEED OR SPEED LOSS = UNKNOWN
    ALTITUDE LOSS = UNKNOWN, BUT IT IS PRESENT

    TIME FOR MANEUVER-L = 16 SEC (TIME.L)

    STATEMENT 2 (BY SQUIRL)
    WE HAVE MANEUVER-B
    PLANE = KI-61-IB
    ENTRY SPEED = 313KM/H
    BANK = 75°
    UNLIMITED NUMBER OF TURNS (AT LEAST 10)
    SPEED IN MANEUVER = CONSTANT 313KM/H
    FINAL SPEED = ENTRY SPEED = CONSTANT 313KM/H
    ALTITUDE LOSS = 0M (NO LOSS)

    TIME PER 360° = 16S. LET'S NAME IT TIME FOR MANEUVER-S (TIME.S)

    SQUIRL, PLEASE PROVE THAT

    TIME.S = TIME.L

    THIS IS REQUIRED FOR -BW- TO CHANGE SUSTAINED TURN TIME FOR KI-61-IB (TIME.S) INTO 16S.

    I'M FUCKING TIRED WITH CONFUSUION "TIME.S=TIME.L"
    THE ONLY THING I HOPE THAT YOU, SQUIRL, CONFUSE TIME.L WITH TIME.S WITHOUT INTENTION TO FALCIFICATE THAT.
     
    Last edited: Jan 29, 2005
  8. -exec-

    -exec- FH Consultant

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    don't mess spitfire into that.
    i can talk about spitfire or about hien, but not similtaneously.
    spit discussion and hien discussion can be parallel, and never to cross together.
    or else you can consider me as "lost to all reasoning in this subject of putting spit and hien[with 1:72 too] into one mess".

    as far as i know, you discussed spit/hien comparison with presslufthammer, and hammer displayed you calculations of better spit turning. am i wrong?
     
  9. squirl

    squirl Well-Known Member

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    Centrifugal force n : the outward force on a body moving in a curved path around another body (force acting outwards on plane)

    Centripetal force n : the inward force on a body moving in a curved path around another body (lift)

    More research will come later.
     
  10. -exec-

    -exec- FH Consultant

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    offtopic:
    actually i gratuated from applied-math faculty of local university.
    and they read a two courses of mechanics to us.
    at least i can check english-russian dictionary and to understand terms "centripetal force" and "centripetal acceleration" at once.
    not meaning i knew out those terms in the school.
    :shuffle:

    ok. to be more math-ly correct:
    |centrifugal force| = |centripetal force|
    vector form of the formula is centrifugal force = -1·centripetal force.
    centrifugal force / centripetal force = -1.
    :D
    what can you get from that, since all sustained turns and any curvilinear motion have the centrifugal force = -1·centripetal force despite of plane type ;) don't answer this question. just joking.
    ________________________________

    so. we (me and you) finished at the point where you must prove 16s/360°@75°"sustained"=16s/360°@90°"energy loosing".

    go on, pls.
     
    Last edited: Jan 29, 2005
  11. gryphon

    gryphon Well-Known Member

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    i know its mosly off topic but i found it an intresing read and some staments that cought my attention.

    of intrest to curent flaming:

    maby i16 is NOT over modeld and japn had easy time like alsop beleaves?

    ?? curent flight models in fh id much rather trade p38 for a p40 verse ki. ??
    again i wonder if p38 is modaled right or not? p40 can survive to dive at same speed that a p38 sufers control issies yet performs better every over way except lvl flight speed. by freehost standerd why would u want a p38 to combat ki?

     
  12. squirl

    squirl Well-Known Member

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    There is insufficient information to determine the exact conditions of that turn. I dont think any airplane can maintain altitude in a 90-degree banked turn. I put forward the 75 degree bank angle as an exclusive situation that perfectly matched the results of the test in the information I received.

    My original intent in this thread was to prove, using engineering concepts, that the Ki-61 is a good turn fighter. I had to use engineering concepts because real turn data was seemingly impossible to find. It took an enormous search and some cooperation from hard-to-reach people to obtain the data we do have; but even this precious data "is not good enough."

    As I have shown, I can extract a great amount of information from concepts that use easy-to-find information (weight, wing area, aspect ratio, wing camber and wing geometry). I don't want to sound repetetive, but I have made all of these conclusions from those 5 simple factors:

    Case #1:
    -The Spitfire IX has a wing loading of 30.8 lbs./sq. ft.
    -The Ki-61-Ib has a wing loading of 32.1 lbs./sq. ft.
    Conclusion: In this basic evaluation the Spitfire IX should turn slightly better than the Ki-61-Ib.

    Case #2:
    -The Ki-61's wing loading is only 4% more than the Spitfire IX's.
    -Other factors in the Ki-61's wing design make it produce more lift than the Spitfire IX's wing. These are ranked in importance:
    1. The Ki-61-Ib has a more cambered (curved) wing; wings with more camber produce more lift (especially because the speed of the air on the top of the wing has an exponential effect on the amount of lift produced).
    2. The Ki-61-Ib has a tapered wing; according to Private Pilot Manual, tapered wings are "...relatively efficient with reasonable weight, drag, and construction costs, as well as [highlight]good slow-flight capability[/highlight]." The same text states that elliptical wings are "...more efficient in terms of weight and drag, but [they] have [highlight]less desirable slow-flight characteristics [/highlight]and [are] more expensive."
    3. The Ki-61-Ib has a wing with a higher aspect ratio; higher aspect ratio wings produce less drag for the same amount of lift.
    Conclusion: In this more technical evaluation, the Ki-61-Ib should easily out turn a Spitfire IX.

    Case #3:
    -Planes have design trade-offs.
    -One trade-off is that the amount of lift is inversely proportional to airspeed (lift causes drag).
    -Engine horsepower is not very influential in top speed (it has some influence but other factors, such as wing design and skin drag, are more relevant).
    -If the Spitfire IX is faster than the Ki-61, then it is likely that its wing produces less proportional lift.
    -If the Ki-61 produces more lift than the Spitfire IX, then this is the major contributing factor to the fact that the Ki-61 is slower than the Spitfire IX.
    Conclusion: In this literal evaluation, the Spitfire IX is the faster plane, the Ki-61 is the better turner.

    Let me make it clear that I am not waging an all-out war against the Spitfire. I am simply proving that the Ki-61 should turn better than the Spitfire IX, using aerodynamic concepts. The Spitfire was a good turn fighter, but the Ki-61 was better :). The Spitfire, for example, should be able to easily out turn a 109 F2, but that is a different "battle" that needs fought.

    I cannot directly determine actual turn times from the concepts I used in evaluating the turning ability of the two planes. I can only make the following statement(s):

    Ki-61-Ib's turn rate>Spitfire IX's turn rate
    Ki-61-Ib's turn radius<Spitfire IX's turn radius

    -Exec-, you mentioned that I cannot tie the Spitfire IX and the Ki-61 together in the same conversation. However, one can do so. If I were to say, "the Ki-61 turns better," you would not be able to make any conclusions. On the other hand, if I said, "The Ki-61 turns better than the Spitfire IX," you could make a conclusion. The Ki-61 and Spitfire IX are indeed tied together, in relativity. Relativity is the core of air combat; relativity determines the margin of strengths in one plane over another plane's strengths.

    I may not have specific data showing what the actual turn performance of the Ki-61 was; but I have data showing the actual turn performance margin the Ki-61 had over the Spitfire IX.

    At this point, I think that we have found all the information we are ever going to find about the Ki-61's turning capability. The only option left us is to base a conclusion off of solid research that applies to all planes, using numbers that are of unquestionable accuracy (weight, wing area, aspect ratio, wing camber and wing geometry). I have already done this, and I stand by my conclusion that the Ki-61-Ib should have a superior turning capability relative to the Spitfire IX.

    By the way, thank you, gryphon, for the interest and research :).
     
    Last edited: Jan 29, 2005
  13. Allsop

    Allsop Well-Known Member

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    As zembla has said, they arnt worried about exact information "his words" but a good idea of how something performed as compaired to others- here squirl proves that the ki61 has about a 4% deviance from the spitfire ix....So why is it such a hastle to give a good plane its good performance back?
     
  14. Zembla JG13

    Zembla JG13 FH Beta Tester

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    Nono, you're twisting my words. That's how I said I'd like it to be... I don't speak for the developers.

    But I guess squirl agrees with me that relativity is more important than 5kmh of top speed differences instead of 10.

    That's just my vision though, and its no guarantee the developers share that.

    <Z>
     
  15. RolandGarros

    RolandGarros Well-Known Member

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    Fight at 20,000' like it was in WW2 & you'll trade your curtis for a lockheed without hesitation
     
  16. gryphon

    gryphon Well-Known Member

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    lol ive never acculy seen a fight that high. been that high only a few times and had to dive down to find a fight :)
     
  17. squirl

    squirl Well-Known Member

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    I've heard some talk that these issues are fixed in 1.64; I hope I am hearing right.
     
  18. Allsop

    Allsop Well-Known Member

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    No action takes place at operational altudes because reds have no need to go that high and golds must stay low to try to get them.

    The ki61 performed well in its handling regardless of altitude- a good turner is a good turner is a good turner.

    And as far as v1.64, we can only pray.
     
  19. RolandGarros

    RolandGarros Well-Known Member

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    Above about 25,000' the P-47 was the a great turnfighter, but a pig at low alts. most normally aspirated planes would be lucky to make even a standard rate turn at 25,000'
     
  20. Allsop

    Allsop Well-Known Member

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    wOW GARROS! YOU NAMED ONE PLANE! GOOD JOB!

    Fact of the matter is- between the russian low altitude planes. And the low level bombers like the pe2 and il2. That you will almost never see a red above 15k feet unless its to intercept a buff, or because they decided they want to take the scenic flight. Squads like the kg51 here actaully take the time to climb their buffs "most of the time" to a good safe altitude before going to their target. But theres no need for fighters really to ever go that high as usually they will ask for escorts ahead of time, or the fighters are doing their ting on the sub 10k side of things.

    BTW- The p47 is and never will be a true turn and burn aircraft. A brick, Is a brick, just maybe a little less so at 25k feet...but could that be dilusion from lack of oxygen?