P-39 D Aircobra vs. Me-109

[Soren]

Found the German report on my harddrive, here we go:

[Soren]

The adjustment of the ailerons was a problem plagueing the early FW190 especially, not that it couldn't be done, it was just a very sensitive procedure.

[FLYBOYJ]

The adjustment of the ailerons was a problem plagueing the early FW190 especially, not that it couldn't be done, it was just a very sensitive procedure.

I went to the link you gave me but none of the photos showed up - again I'd like to see the procedure on adjusting the Fw 190s ailerons. Not saying that mis-adjusted ailerons would not cause a problem, I question how difficult the process could actually be. Even with a series of pushtubes, push-rods and bell cranks "solid rigging" is the easiest flight control system to maintain and adjust. Many times the factory will give dimensions on specific push-rods that should provide the specified control surface deflection. In my experience (and this includes warbirds) if you have all the push-rods and push tubes set correctly and cannot get the proper surface deflection, that usually means you have something bent or mis-aligned - a control surface bracket, part of the airframe or even the control surface it self. If this procedure is that difficult I would also look at the precision of the airframe and the actually parts that make up the control system.

[renrich]

I have read the report ot the flight tests of the FW190A4 versus the F4U1 and F6F3 three or four times and I can find no mention of misadjusted ailerons. In fact the report mentioned how easy it was to roll the FW and there was no mention of any vibration of the controls except at very high speeds. One would think if the FW was not performing in a manner typical for the German AC, the Navy would either note that like they did another couple of problems or they would have fixed the problem. As it was the Navy concluded that the Corsair and Hellcat were both superior in combat. Of course nothing was said about the fact that both Navy AC carried approx 100 gallons more fuel so in extremis all the had to do was keep turning or looping until the FW ran out of fuel and then dispose of it at their leisure. One wonders if that 600 pounds of extra weight the US planes carried had any effect on their performance.

[drgondog]

I have read the report ot the flight tests of the FW190A4 versus the F4U1 and F6F3 three or four times and I can find no mention of misadjusted ailerons. In fact the report mentioned how easy it was to roll the FW and there was no mention of any vibration of the controls except at very high speeds. One would think if the FW was not performing in a manner typical for the German AC, the Navy would either note that like they did another couple of problems or they would have fixed the problem. As it was the Navy concluded that the Corsair and Hellcat were both superior in combat. Of course nothing was said about the fact that both Navy AC carried approx 100 gallons more fuel so in extremis all the had to do was keep turning or looping until the FW ran out of fuel and then dispose of it at their leisure. One wonders if that 600 pounds of extra weight the US planes carried had any effect on their performance.

Gene (Crumpp) is rebuilding an Fw 190 with his restoration group in Florida. As I recall he says a.) easy to spot if out of rig, and b.) easy to adjust (pre-flight) so I don't think this represents much of a test 'distraction' or operational issue.

[Soren]

The high speed vibration of the controls is the key, this doesn't happen in a FW-190 with properly adjusted ailerons as explained in the German report. The German report also notes how difficult it is to adjust the ailerons correctly on the FW-190. It was a very real problem.

Also Crumpp is the one who has pointed this problem with the NAVY tests out, and he works on an actual FW-190. The NAVY report notes ailerons vibrations at various speeds, clearly indicating improperly adjusted ailerons. This also explains the FW-190 poor turn performance in those tests.

[renrich]

The Navy report I read did not mention any aileron problems or vibrations except at speeds approaching the dive limits which I believe they attributed to compressibility. As I mentioned the Corsair was one of the best rolling AC in the US inventory and very high roll rates have been attributed to it so it is no slur to be equated with it in the roll category. I do wonder about 2 second 360 rolls.

[Mitya]

You need to read up on the aerial conflict in the east.

Like I said many times there weren't even 1/10th of aircraft present that the Soviets would claim, and this is documented fact. A similar example is the outrages Soviet claims at the battle of Kursk.

Sorry but the Soviets were the record holders when it came to outrages propoganda claims, and there are plenty of examples, infact let me present another quicky: The famous duel between Vasili Zaitsev and Major König/Thorvald, well it just so happens that there never was any Major König or Thorvald in Stalingrad, infact there wasn't a single scharfschütze in the city let alone a Major.

PS: The story about Budanova and Litvyak is complete hogwash as-well, read LW records and you'll realize this quickly.

And you read about war on the Soviet-German front not only to German sources? And Soviet and Russian did not read? A question for the sake of curiosity... I think, that, чотбы normally to know a history of the conflict it is necessary to esteem not only one side, but also another. Whether not so?
Example p-39:
Any propogand...

[kool kitty89]

What do the top 2 pictures have to do with the P-39?

[kool kitty89]

2 other things to note, the P-39 featured the NACA 23000 airfoil on the outer portions of the wing. (0015 at root)

And that take-off ratings and military power ratings don't necessarily equate to the max output, or WEP.

The only models that were rated for 1150 hp max were ther early ones (-D/D-1 and P-400) with the -35 engine.

On the D-2 take-off was rated at 1,325 hp with it's -63 engine. Similar engines were used on most models up to the N variant -and some refitted M's-. (which featured a higher blower ratio which limited max boost due to higher air temperatures, but allowed a significantly higher critical altitude of ~17,500 ft for 1125 hp mil power with high speed level flight ram air. similar engines were used on the P-47M/N ans P-51A, and could produce 1,480 hp at 10,400 ft with ram, but were limited to 1,200 hp take-off by carb air temp and 57" Hg limit)

Except for the early allisons of the P-39D/D-1/P-400 (-35) which were limited due to strucural limits of the spur gear iirc (same for the P-40B/C's -33), all 8.8 rato blowe allison engines were rated for a WEP of 60" hg which resulted in 1,570 hp. Albeit with a relatively low crit alt for these power levels.
These included the P-39D-2's -63 engine (and all other P-39's up to the M model) and the P-40D/E/K.

As mentioned earlier the more powerful 9.6: 1 blower was limited to 57" Hg due to risk of detonation (the 8.8 could go up to 70" w/out problems, though there were risks of structural failure due to the high power levels). This allowed a crit alt of 10,400 ft for 1,480 hp in level flight, and 1,125 at 17,500 ft. (lower alts for climb) These engines were the -81, -83, and -85. (and -99) in USAAF designations. And were used on the P-39N/Q (-85) and some M's, as well as the P-40M/N and P-51A (-81)

This gave the late model P-39Q (with no wing guns and a 4-blade prop) a top speed of ~396 mph at ~12,000 ft at WEP. (the P-51A could manage 415 mph, and the P-47M 378 mph) with initial climb of


See: http://www.raafwarbirds.org.au/targe...39%20abuse.pdf
Perils P40 Archive Data
Bell P-39 Airacobra


note these take-off ratings and how they drop at the P-39N/Q



And also:

[kool kitty89]

Also as far as performance is concerned the P-39 was superior to the contemporary P-40 in all but roll-rate and range, being ~equal in sustained turn, depending on configuration.

Another thing though was that the P-40 was easier to fly and had a larger cockpit. (the P-39's short canopy limited pilot height to ~5'8" -thanks to the USAAC's redesign to the low profile canopy -which also limited view)

The 2-other harmfull changes made at Wright field (besides the turbo) was clipping the wings quite a bit (thus increasing wing loading and possibly limiting space for internal stores) And lengthening the P-39's rear fusalage, shifting the CoG aft and worsening the already mediocre stability. (the only positive changes were the improved nose streamlining, enlarged tail fin, and ellimination of the fusalage radiator/oil-cooler intakes and adding the wing root ones)


The P-40 Tomahawk had a max fuel capacity of 157 US gall (may have changed on late models, the P-40N's was 122 gal) while the P-39's max internal load was 120 US gal -limited to 87 (variable to mod back to 120) or 92 US gal (fixed N/Q) on late models. Both the P-40 and P-39 could carry up to a 170 US gal drop tank (more on the P-40N with 3x racks).

But the limiting factor for radius is max clean range which was ~850 mi for the P-40 (over 1,000 mi at minimum cruise), later limited to ~660 mi with the P-40N; and ~720 mi for the P-39 (120 gal) or 522 mi with 87 gal. (both cruising at ~200 mph)

The P-63 carried only 100 gal internal, so despite an impressive "yardstick" range of nearly 2,500 mi (with 2x 75 and 1x 175 US gal drops) the max combat radius was under 600 mi.

Ther armaments are another issue and changed somewhat on both a/c and could be a matter of circumstance, use, and pilot prefrence. (Tomahawk carried ~50% more .50's but 1/2 the .30's and the P-39 had the cannon as well. comparing the early models. the tomhawk would run out of .30's first the P-39 out of .50's and the 20 mm carried only 60 rounds while the 37 mm carried 30-33 rounds -usually a 1-hit kill if you could hit a fighter)

[Mitya]

What do the top 2 pictures have to do with the P-39?

"Or at you Alission works out 100...150 hours, or 30 hours, and even it is less, but you force down Bf-109 and FW-190..." For what 2 upper books you ask? Here go: ß Ïîìíþ -- I Remember - Ãëàâíàÿ
If I am not mistaken, the most successful ace on P-39 has brought down on Pacific ocean 5 airplanes of the opponent, then flight on F6F... In the USSR on it many aces completed war...
In the USSR removed a part of inventory, for example oxygen bottles. And what for they are necessary, if battles do not go above 4000 m? From Cobras removed wing to machine gun - weight much, and to sense hardly. A part of armouring removed...What performances of the Cobra after such will be? On your digits, unfortunately, it to not find...
P-39Q10 it is already possible to consider as the Soviet fighter. Him have made on wishes of the Soviet pilots and recommendations TSAGI.
P-63 especially.

[kool kitty89]

Ok, so those are books on the topic.


Did they remove the 4x .30 inch wing guns as well, or just the 2x .50 wing guns of the P-39Q? (removing the Q .50's added ~15 mph I think)

The under-wing mounted .50's had a lot more of an effect on performance than the internal .30's.



One thing to note as well is that the Il-2 Sturmovik computer game Ил-2 Штурмовик (игра) — Википеди� has a fairly comprehensive limrary on the aircraft featured in it. Particularly the Russian (or Lend-lease) planes. One interesting point is that turn times are listed for many planes as well (at 1,000 metres).


I was also aware that the Russians tended to "abuse" theis Allison engines of lend-lease aircraft (runing them at high sustained power levels and RPM) to give them a performance advantage when entering the fight. That, of course, severely limited engine life. (this was particularly common with the P-40 due to its lower performance)



Here's a similar discussion: http://www.ww2aircraft.net/forum/avi...a-12342-3.html (P-40 vs. ME-109)

[Mitya]

Ok, so those are books on the topic.


Did they remove the 4x .30 inch wing guns as well, or just the 2x .50 wing guns of the P-39Q? (removing the Q .50's added ~15 mph I think)

The under-wing mounted .50's had a lot more of an effect on performance than the internal .30's.



One thing to note as well is that the Il-2 Sturmovik computer game Ил-2 Штурмовик (игра) — Википеди� has a fairly comprehensive limrary on the aircraft featured in it. Particularly the Russian (or Lend-lease) planes. One interesting point is that turn times are listed for many planes as well (at 1,000 metres).


I was also aware that the Russians tended to "abuse" theis Allison engines of lend-lease aircraft (runing them at high sustained power levels and RPM) to give them a performance advantage when entering the fight. That, of course, severely limited engine life. (this was particularly common with the P-40 due to its lower performance)



Here's a similar discussion: http://www.ww2aircraft.net/forum/avi...a-12342-3.html (P-40 vs. ME-109)

Yes! You are absolutely right in use of technics. Therefore results on Pacific ocean and somewhere on Kuban so differ from action P-39...
Russian cheater's. )))
OFFTOP: and you in IL-2 play?

[Soren]

Let us not use a game as reference plz, it is after-all a game.