Crumpp Posted December 3, 2015 Posted December 3, 2015 The topic is the lift polar for the Bf-109K4 and using the 2D data for the airfoil. Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Hummingbird Posted December 3, 2015 Posted December 3, 2015 Of the wing Hummingbird...NOT THE AIRFOIL POLAR. In that case it is 1.53 to 1.55. That is the 2R1 12 airfoil polar.
Crumpp Posted December 3, 2015 Posted December 3, 2015 You are killing me. Now, do you understand Aspect Ratio has no effect on 2D airfoil data? Why is that? 2D airfoil data has an infinite Aspect Ratio. Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Crumpp Posted December 3, 2015 Posted December 3, 2015 In that case it is 1.55. Ok now we are getting somewhere. 1.55 - .2 - 1.35 to ballpark the aircraft's CLmax. That is within the Mtt Bf-109G polar. Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Hummingbird Posted December 3, 2015 Posted December 3, 2015 (edited) What are we talking about and what is the point here? The actual aircraft Clmax or something else? There are many 2D Clmax curves for the 2R1 and similar 24xx going upwards of 1.8, just as with the 23xxx series. Thought we were looking at the Clmax of the whole wing here. Edited December 3, 2015 by Hummingbird
Crumpp Posted December 3, 2015 Posted December 3, 2015 There are many 2D Clmax curves for the 2R1 and similar 24xx going upwards of 1.8, just as with the 23xxx series. Exactly. What are the Re? What is the Chord of the section? Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Hummingbird Posted December 3, 2015 Posted December 3, 2015 (edited) Exactly. What are the Re? What is the Chord of the section? Re = 8.0*10^2, 2R1 12, NACA 2412, 23009 & 23012 all floating around 1.6 CLmax. And there are charts for the exact same Re showing them all floating around 1.75 to 1.8. Incidentally I seem to remember that the Germans arrived at a 1.5 CaMax polar for the Fw190 at Charlais Meudon as well (0.02 higher than 109V24). But FW AG lists a CaMax of 1.58. Hence why I refered to this as a more accurate representation of the overall CLmax of the whole wing as both planform, airfoil choice and slat design is similar: Edited December 3, 2015 by Hummingbird
Hummingbird Posted December 3, 2015 Posted December 3, 2015 (edited) On a sidenote I just had an online dogfight with an P-51 and he was able to stay on the tail of my K-4 in a sustained turn at 380 km/h for 3 circles. He ended up turning inside me and shooting me down. Pulled just enough to sustain 380-400 km/h in the level turn, yet he still outturned me. So you were right when u said that the P-51 now turns like a Zeke ingame. In addition to this the 109 engine is now quite easily damaged with throttle changes for some reason. Edited December 3, 2015 by Hummingbird
Crumpp Posted December 3, 2015 Posted December 3, 2015 Do you have the whole report because I do not see any airfoil data on that page. What I read is they changed the design of that wings slat. Give me something I can see that ties that page to the Bf-109. Outside of slats, I see nothing. I might have it and will look for it. Incidentally I seem to remember that the Germans arrived at a 1.5 CaMax polar for the Fw190 at Charlais Meudon as well (0.02 higher than 109V24). But FW AG lists a CaMax of 1.58. Yes they did. In that case I have the data sheet used by Focke Wulf to make performance predictions and a plethora of 2D data with known Reynolds numbers/chords as well as know wind tunnel conditions for the entire aircraft's polar. An excellent analysis could be made which is one reason why I shared it. It says 1.58. For Mtt, I have a calculated turning performance report, RAE turning performance report that agree but only really represent the possibility of the root airfoil. I have a wing polar from the Bf-109G series that seems to be applicable. I don't know for sure and need more data to make a concrete conclusion. The polar was given to me, is labeled clearly, and I was told it was the Bf-109G lift polar. That is why I used the 1.41 because it agreed with RAE, Mtt, and Bf-109G polar. Good stall speed and weight data would be nice if anyone has it. You do realize that this polar clearly shows the Clmax is ~1.55? http://forums.eagle.ru/showpost.php?p=2581185&postcount=85 The radiator flaps must be at 40 degrees to achieve a Clmax of 1.55 is all. Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
ED Team NineLine Posted December 3, 2015 ED Team Posted December 3, 2015 On a sidenote I just had an online dogfight with an P-51 and he was able to stay on the tail of my K-4 in a sustained turn at 380 km/h for 3 circles. He ended up turning inside me and shooting me down. Pulled just enough to sustain 380-400 km/h in the level turn, yet he still outturned me. So you were right when u said that the P-51 now turns like a Zeke ingame. In addition to this the 109 engine is now quite easily damaged with throttle changes for some reason. Or you got outflown... ;) Forum Rules • My YouTube • My Discord - NineLine#0440• **How to Report a Bug**
Crumpp Posted December 3, 2015 Posted December 3, 2015 On a sidenote I just had an online dogfight with an P-51 and he was able to stay on the tail of my K-4 in a sustained turn at 380 km/h for 3 circles. He ended up turning inside me and shooting me down. Pulled just enough to sustain 380-400 km/h in the level turn, yet he still outturned me. So you were right when u said that the P-51 now turns like a Zeke ingame. In addition to this the 109 engine is now quite easily damaged with throttle changes for some reason. So it begins.... How much fuel did you take? http://forums.eagle.ru/showthread.php?t=154014 Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Crumpp Posted December 3, 2015 Posted December 3, 2015 You can go all way to the stall point. Just do not go below that first nibble speed. Answers to most important questions ATC can ask that every pilot should memorize: 1. No, I do not have a pen. 2. Indicating 250
Hummingbird Posted December 3, 2015 Posted December 3, 2015 So it begins.... How much fuel did you take? http://forums.eagle.ru/showthread.php?t=154014 I was at 50% at that point, he was probably below that, but regardless of that he shouldn't be able to follow a sustained turn like that.
Hummingbird Posted December 3, 2015 Posted December 3, 2015 Or you got outflown... ;) SiTh I was holding it level at SL, so was he. I was interested to see if he could follow if I pushed as far as holding 380 km/h level, and he could, infact he not only stayed with me he also turned inside me and shot me down. Had I known that the ingame P-51 could turn like a Spitfire I wouldn't have tried that ;) But it was a test and indeed the Mustang atm turns a lot better than it used to, at least as far as I can tell.
Hummingbird Posted December 3, 2015 Posted December 3, 2015 I've set up a WW2 DACT server for anyone wishing to test it out further.
gomwolf Posted January 19, 2016 Posted January 19, 2016 About CLmax... Flügel allein means wing alone. It looks CL diagram without slat. I got polar drag of NACA 2R1 14.2 with Reynols number 20mil. It is almost same with CL diagram of closed radiator. I attached it. And.. I asked this to Flugmuseum Messerschmitt few month ago. They are the most experienced organization about Bf109 in these dyas. They answered my question. Bf109G-4. 2,650kg. 140km/h. Without flap and undercarriage. CLmax is around 1.7. 1
Hummingbird Posted January 19, 2016 Posted January 19, 2016 Flügel allein means wing alone. It looks CL diagram without slat. I got polar drag of NACA 2R1 14.2 with Reynols number 20mil. It is almost same with CL diagram of closed radiator. I attached it. And.. I asked this to Flugmuseum Messerschmitt few month ago. They are the most experienced organization about Bf109 in these dyas. They answered my question. Bf109G-4. 2,650kg. 140km/h. Without flap and undercarriage. CLmax is around 1.7. Yeah this is exactly as listed on some MTT papers.
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