pixelshader Posted February 2, 2014 Posted February 2, 2014 On first try I hit a max mach number of 0.96 at around 3500m. I wonder if a LaGG could do better, or maybe if I could get someone to shoot my wings off first..
J4SCrisZeri Posted February 2, 2014 Posted February 2, 2014 Boumm!!! How comes your wings didn't rip off at that speed?
Fifi Posted February 2, 2014 Posted February 2, 2014 (edited) Yeah, DM should be improved in that particular matter! Edited February 2, 2014 by Fifi 1
LLv34_Flanker Posted February 2, 2014 Posted February 2, 2014 S! Well, the FM needs more work than DM first it seems 1
Finkeren Posted February 2, 2014 Posted February 2, 2014 Well the high speed dive tests of the Spitfire in 1943-44 reached 0.96 Mach, and the worst they ever got was a broken propeller, so I don't see why the Bf 109 should lose its wings 2
Finkeren Posted February 2, 2014 Posted February 2, 2014 Because Gunther Rall said they would. LOL! Good one
DD_bongodriver Posted February 2, 2014 Posted February 2, 2014 (edited) I came in and got to the leader of the wolf pack and got his left wing. Flames you know. With this tremendous amount of fuel you get a flame. Then I cut to the right and I was hunted. Then they chased me. I should tell you the numbers. It was 800 4-engine bombers, B-17, B-24. This is a parade of 2 hours. They had cover of 1200 fighters from the Hartz mountains down to Stutgard. Always in 4, 4 or other formations. So it without chance. Anyway, I was chased by P-47. I knew exactly that in a dive P-47 is much faster than 109. And the P-47 has a much higher structural strength. They can go up to 1400 kilometers per hour. The 109, if you go to 1000, pull it up, you risk that the wings come off. So I went down from that, bang, bang, bang. I was chased by what we call line abreast, 4 p-47s. And all that shooting here and all of a sudden bang. The left hand was on the throttle and came off and the thumb was off. Finally, I managed. This was a very traumatic thing, certainly. I pull up, when I was down, to the stalling point. The couldn't follow me because these P-47 wanted to fly back to England. And I want to get rid of my airplane. I don't care for the airplane, I want to get out of this. I managed that. This was very difficult because I was hanging outside. I couldn't operate with this hand, nothing. Finally it worked and I pulled the parachute way down and I came down safely and was hanging on a tree. Gunther Rall. 4th paragraph in the 'back to germany' chapter of this web link http://www.virtualpilots.fi/hist/WW2History-GuntherRallEnglish.html the Spitfire was selected for the dive tests it did because at the time it was the aircraft with the highest limiting mach number. Edited February 2, 2014 by DD_bongodriver
Emgy Posted February 2, 2014 Posted February 2, 2014 Pixelshader didn't pull up though, he dove straight into the ground.
DD_bongodriver Posted February 2, 2014 Posted February 2, 2014 Pixelshader didn't pull up though, he dove straight into the ground. That's true, guess it solves the problem of pulling wings off your 109, just lawn dart it instead, mind you it is rumoured that in a high speed dive you couldn't pull out in a 109 anyway.
JtD Posted February 2, 2014 Posted February 2, 2014 Well the high speed dive tests of the Spitfire in 1943-44 reached 0.96 Mach, and the worst they ever got was a broken propeller, ... That's not true in many ways. First, the Mach 0.96 was measured with inadequate instruments and the figure is highly unreliable. Second, this speed was recorded in the 1950'ies, third it wasn't during high speed dive testing but during a flying incident. The highest speed measured in the 1943-44 window was Mach 0.92, and even this figure is questionable because of inadequate instrumentation. Also, the British did lose complete aircraft in high speed dives due to structural failures. Even the aircraft of the successful Mach 0.92 dive was a more or less complete write off after the test, with the entire aircraft bent and twisted, including the wings which were swept back. Speeds in excess of about Mach 0.9 basically were impossible with WW2 fighter aircraft, in particular production variants. An aircraft like the 109 would not attain 0.96 as in the video, wouldn't do it at 3500m if it did, and it wouldn't still have its wings if it did. It's physically impossible. WRT video, with the exact atmospheric conditions unknown it actually is possible that this was supersonic. Good to see the lateral instability being modelled, but bad to see such high speeds.
SKG51_robtek Posted February 2, 2014 Posted February 2, 2014 Afaik one had to trim the 109 nose heavy just to stay in a steep dive with somehow reasonable stick forces. Given enough height there should be no problem to come out of the dive by carefully returning the trim to neutral. In a fight however one would be a perfectly still sitting duck for the attacker with the better suited plane in this situation.
siipperi Posted February 2, 2014 Posted February 2, 2014 Not sure if wings can rip off at this point. Before Christmas I tested high G turn after max speed and nothing happened. Haven't tested since.
pixelshader Posted February 2, 2014 Author Posted February 2, 2014 (edited) That's not true in many ways. First, the Mach 0.96 was measured with inadequate instruments and the figure is highly unreliable. Second, this speed was recorded in the 1950'ies, third it wasn't during high speed dive testing but during a flying incident. The highest speed measured in the 1943-44 window was Mach 0.92, and even this figure is questionable because of inadequate instrumentation. Also, the British did lose complete aircraft in high speed dives due to structural failures. Even the aircraft of the successful Mach 0.92 dive was a more or less complete write off after the test, with the entire aircraft bent and twisted, including the wings which were swept back. Speeds in excess of about Mach 0.9 basically were impossible with WW2 fighter aircraft, in particular production variants. An aircraft like the 109 would not attain 0.96 as in the video, wouldn't do it at 3500m if it did, and it wouldn't still have its wings if it did. It's physically impossible. WRT video, with the exact atmospheric conditions unknown it actually is possible that this was supersonic. Good to see the lateral instability being modelled, but bad to see such high speeds. You are right, I forgot all about Stalingrad being so cold. The 0.96 number is with standard atmosphere of -7.75 degrees at 3500m (I am using http://www.hochwarth.com/misc/AviationCalculator.html), but it's probably colder than that on the ground. If I subtract ~20 degrees it is actually a hair over mach 1 at 3500m. I don't know the relation between ground temp and temp at altitude but it is definitely possible that it was supersonic. Edited February 2, 2014 by pixelshader
J4SCrisZeri Posted February 2, 2014 Posted February 2, 2014 Well the high speed dive tests of the Spitfire in 1943-44 reached 0.96 Mach, and the worst they ever got was a broken propeller, so I don't see why the Bf 109 should lose its wings Something was wrong earlier in the other sims then, including il2 1946 I remember loosing my wings several times with a bf109, during a dive, past 800-850 kmh
HagarTheHorrible Posted February 2, 2014 Posted February 2, 2014 Interestingly Gunther Rall mentions a problem with the slats during his first combat with French Hawks.
Finkeren Posted February 3, 2014 Posted February 3, 2014 I might well be wrong about the Spitfire trials, but I wouldn't trust Ralls word on this either. Even though he flew more hours in the 109 than almost anyone else, he was no test pilot and the conditions he flew under weren't exactly controlled or able to give any reliable data.
Panzerlang Posted February 3, 2014 Posted February 3, 2014 I believe it's somewhat well established that a 262 was taken to beyond the speed of sound (not proven). The pilot described features of the experience that tally with SS flight records of later years.
DD_fruitbat Posted February 3, 2014 Posted February 3, 2014 Sits back and reaches for the popcorn....
BlackDevil Posted February 3, 2014 Posted February 3, 2014 (edited) Yeah, DM should be improved in that particular matter! Can you specify, what you don´t like ? Wing falling off due to speed without g is just stupid nonsense. Edited February 3, 2014 by BlackDevil
JtD Posted February 3, 2014 Posted February 3, 2014 The dive limit for the Bf 109F-4 was 750 km/h indicated, according to the handbook. German regulations of the time required a 30% speed reserve against structural failure, which means the wings would fold back at 975 km/h indicated. When the regulations the 109 was constructed after were laid down, transonic drag increases were pretty much unknown, and the real air frame stress at 975 km/h would be considerably larger than what was the basis for the calculation. In the video, you can see speeds in excess of 1000 km/h, which alone would be enough to rip a wing clean off or the plane apart. No g load necessary.
Brano Posted February 3, 2014 Posted February 3, 2014 Gunther Rall says that thunderbolt could do 1400km/h in dive? Well,that one certainly sounds like me with several beers flushed down my throat and saying ''True story,my friend'' But I think he was exaggerating on purpose.
DD_bongodriver Posted February 3, 2014 Posted February 3, 2014 Sits back and reaches for the popcorn.... toffee or salted?
69th_chuter Posted February 3, 2014 Posted February 3, 2014 (edited) Very interestingly, to me, anyway - lol, I've just been researching 109 dive tests. The ones most pertinent to the game are tests done by a 109F fitted with G wings (with aileron travel reduced by 50% to prevent pilot overcontrol) and, after the first dive, what they called in the report the G tail (the tall tail). Dives started from nearly 11 kilometers at 240 kph and an aircraft weight of 2900 kg. Angle of dives were about 75 degrees after rolling over (as opposed to bunting or pushing over) with power set at 100% after initial dives at idle then 1.0 ATA. Trim was set at +1 deg 15 sec. Ultimately, max true airspeed was found to be 906 kph at an altitude of 5.8 km with max mach of 0.805 at 7.0 km. The same test with engine at idle and prop on auto (all tests in auto) set at 1500 rpm achieved a max speed of 880 kph at 3.8 km. (This would seem to indicate the prop was a significant part of the drag.) In the first tests the aircraft lost directional stability above 800 kph which was followed by lateral instability (rocking or "conoeing"). Installation of the G, or tall, tail eliminated the yawing but nothing was found to prevent the ailerons from snatching back and forth causing the aircraft rocking, pilots generally making it worse. With the trim set at the mentioned +1 deg 15 sec (and a twice as big fixed elevator trim tab that eventually became standard) a pull out could be performed without trim change, another half second nose down trim and the elevator alone could not bring plane out of a dive without trim assistance, but it was considered too easy to dial in too much trim resulting in overstressing when the aircraft reached lower altitudes during pull out to recommend it. Also, it became nearly impossible to dial in more nose down trim at speed so it had to be set before dive. The first part of the dive required holding the stick forward with reducing force until at 4 km it was neutral. Added: Max indicated speed was 737 kph at 4.5 km Edited February 3, 2014 by chuter
69th_chuter Posted February 3, 2014 Posted February 3, 2014 Oh, an interesting side note: the tests were performed between Feb 15 and Mar 12, 1943 and mention was made that on cold days at altitude the stabilizer jackscrew grease would freeze making trim adjustment difficult if not impossible. The recommendation was to use a lower temperature grease in the future ... 1
J2_Trupobaw Posted February 4, 2014 Posted February 4, 2014 On first try I hit a max mach number of 0.96 at around 3500m. I wonder if a LaGG could do better, or maybe if I could get someone to shoot my wings off first.. What's sure it that you did not break the ground barrier .
BlitzPig_EL Posted February 5, 2014 Posted February 5, 2014 Gents, we have been over this ground multiple times in the past. No aircraft from the WW2 period ever broke the speed of sound. No Spit, no 109, no P47, and no 262. I don't care if they were diving straight down from low earth orbit, the laws of physics don't allow aircraft with big honking props on the front, or two very draggy compressor inlets in the case of the 262, to go that fast. The fact that it happens in video games is just an artifact of poor modeling. The fact that people believe it happened in real life is an artifact of too much schnapps. 1
Jaegermeister Posted February 5, 2014 Posted February 5, 2014 (edited) What's sure it that you did not break the ground barrier . Not true, according to the instrumentation, he continued to proceed at 15kph well after impact. Edited February 5, 2014 by Jagermeister
silent_one Posted February 6, 2014 Posted February 6, 2014 The games only , what 38% finished and your complaining about the modeling. lol.
Mogster Posted February 6, 2014 Posted February 6, 2014 Sims just don't adequately model the airframe and control forces at those speeds, especially when the aircraft isn't designed for transonic flight.
Rama Posted February 6, 2014 Posted February 6, 2014 It was said by the dev that the new FM models the compression (so a part of what happen at high speed during transonic flight). Some did experience it?
DD_bongodriver Posted February 6, 2014 Posted February 6, 2014 The games only , what 38% finished and your complaining about the modeling. lol. Game is 38% FM's are 90%
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