Jump to content

Panthera

Members
  • Content Count

    876
  • Joined

  • Last visited

Community Reputation

429 Excellent

About Panthera

  • Rank
    Member

Recent Profile Visitors

926 profile views
  1. Just to supplement JtD analysis, here's a neat NACA chart on amongst other things the L/D of different flap designs:
  2. Well that's 608 kg lighter than in my calcs so that certainly changes things, but out of interest how does the Fw190D9 compare with a similar fuel percentage and 2071 hp in your C++? Btw don't think I ever asked this before, but does your C++ program take into account the increase in Cl with a higher AR ? Would be interesting to plug the Ta152H into it.
  3. It does, but percentage wise it's about the same for both aircraft, and the effect is indeed significant. However as I mentioned before a larger part of the P-38's wing reference area is taken up by fuselage & nacelle structure, and thus you run into the problem of less percentage wise area optimally shaped for generating lift. For sure, I totally agree. Yes, I see no reason why you shouldn't be able to enter an accelerated stall with the flaps down, esp. since this will actually lower the critical AoA of the wing.
  4. If anything it would be nice with a toggable G meter for FM testing Just like we have a toggable true speed indicator.
  5. I'm not saying propwash doesn't play a role, I'm saying it isn't really going to play more of a role for the P-38 than it does for the Fw190 in terms of percentages which is what matters, esp. if we start considering wing reference area taken up by fuselage & engine nacelles. Furthermore the propwash intensity produced by the Fw190 is over the covered area is going to be higher. At 7940 kg vs 4270 kg you would need about a 11% higher Cl to achieve the same load factor, which I don't see as realistic flaps up all things considered. From an AR of 6 to 9 you usually don''t see more than a 7.5% increase, and that's with less reference wing area taken up by fuselage & nacelle structure. I prefer a more precise method, like measuring the sustainable load factor Otherwise I'd have to record my turns, rewatch them and then trust in the ASI etc, which I guess is possible but not usually how I'd do it Anyway IMHO the P-38 should not be outturning the Fw190, P-51 or P-47 flaps up, it can possibly match them, but that's it IMO. As for the 109, and esp. the Spitfire, not a chance.
  6. Instantanous turn rate is where the P-38 loses out to the Fw190 however, due to the higher wing loading. (Both use the same airfoil) As for the 109, the P-38 shouldn't really have a chance here, it's just way too far behind in lift/weight and thrust/drag. Well the problem 1 is I am away from my main pc for the time being, and problem 2 is that I haven't found a way of properly testing it in IL2 as it lacks all the necessary gages, such as a G meter for example. Well realistically the Fw190 should be the one turning slightly better flaps up, so that's an issue IMO. Prop wash shouldn't really effect the P-38 any more than the Fw190, and the P-38 does suffer from have a larger part of its reference wing area taken up by engine nacelles + fuselage. That said the higher AR will actually increase the CLmax, but it won't be by 10% from 6 to 8.2. I believe it's usually around 7.5% from 6 to 9. So the Fw190 should realistically be able to go slower flaps up at the weights you listed. Again they should be close in terms of turning, but the overall advantage should go to the Fw190 all things considered. I don't expect the FMs to be final though either.
  7. Hmm so am I, and I'm getting 1.52 as well, not sure where the 1.65 came from (?), must have misremembered the number. Also could've used weight^2/span^2 myself, but thought it best to explain the equation behind this. Anyway we've now roughly compared the Fw190 with the P-38 and seen that without flaps the P-38 shouldn't really be able to outturn it, esp. not with ease which is what I'm hearing people saying it's doing ingame. With flaps it should be able to rival the Fw190, P-47 & P-51 in the turn, but the 109 and esp. the Spitfire it is really nowhere near.
  8. I guess it comes down to using different figures, I'm relying on the Jumo 213A performance charts which lists 2071 hp with MW50 at SL. I we use 1600 hp for the P-38 then we get a 1.54 ratio difference in power, compared with the 1.65 ratio difference in thrust required using the 7940 kg & 4270 kg weights. Let's not forget the Fw190 has flaps of its own But yeah, using your own figures you're arriving at a similar result as myself.
  9. Ah ok, I read it abit differently, didn't notice the 109's Cl curve stretched further.
  10. Interesting, I still don't understand how the 109 is lower than the P-51, doesn't make much sence IMHO, the 109's power off CLmax should be slightly higher based on everything I've seen. As for the Tempest it's obviously way off, 1.75 is what I'd expect at full power at very low speed.
  11. I see, that's rather low IMHO, unless it's power off. Power on is where the 109 should really shine compared to the slatless aircraft in terms of Clmax - that is at speeds where it's actually able to pull enough AoA have them come out. Haha yeah, that is a pretty hilarious chart 😄 The Spitfire XIV should be above the rest in terms of turning.
  12. I used 7940 kg for the P-38 and 4270 kg for the Fw190. AR is span^2 / wing reference area where I get 6.02 and 8.22 respectively. The Cdi is then calculated as described. The 2050 hp figure was a quick rounding down assuming 2100 ps, which upon looking uo the actual ratio of ps/hp is actually 2071 hp. And I'm ofcourse comparing the Fw190D9 here. Best I could find for the Allison was the 1490 hp, but we can take 1700 aswell in which case we get a ratio of 1.64 which is undoubtedly better than before but I'm still not seeing it beat the 190 round the turn.
  13. Whilst it's true that the high AR helps, we must remember the big size difference between these aircraft on top and the extra Cl and thus drag the P-38 is experiencing in order to conduct the same turn due to its higher WL. But we can compare the AR of for example the Fw190 at 6.02 with the 8.22 of the P-38 and then calculate the Cdi using a Cl compensating for the difference in WL: Cdi = (Cl^2) / (pi * AR * e) P-38 Cdi = (1.118^2) / (pi * 8.25 * 0.8) = 0.060 Fw190 Cdi = (1.0^2)/(pi * 6.02 * 0.8) = 0.066 So that's a 10% difference in Cdi at the same load factor, and this then ofcourse has to be multiplied with the wing reference area of both aircraft, in which case we get a figure about 1.65 times higher for the P-38, whilst the HP available is only ~1.45 higher if my reference numbers are correct (1490x2 / 2050x1). We ofcourse need actual thrust produced to be accurate, and to get a full picture of the drag we also need the Cdo for both aircraft. But with all that taken into consideration I see an advantage for the Fw190 here, even if it's small.
  14. Yeah that's the problem, I really don't see how it should be able to do this considering its major disadvantages compared with the other aircraft mentioned in terms of wing loading, size & therefore drag comared with power required. All the P-38 has is a decent power to weight ratio, but it only has a small advantage here over the P-51 & P-47, and not enough to offset the big disadvantage in the other areas. In terms of aerofoil the P-38 uses the same 230xx series as the Fw190, F6F & F4U, a good high lift airfoil, but not one which would give it anywhere near the Clmax needed to compensate for the huge disparity in wing loading. Hence if what you say about how the aircraft is currently stacking up in IL2 is true, then IMHO there is a big error in the flight modeling.
  15. If it's outturning those aircraft then IMO it is overperforming quite significantly, esp. if its without flaps, as I don't see how it is to overcome its much less favorable wing & power loading to achieve it. IIRC the opinion of German pilots was also that it was the easiest of the Allied fighters to deal with.
×
×
  • Create New...