P-39 D Aircobra vs. Me-109

[drgondog]

I look forward to it. I have been digging around and turned this one up that might be of interest. It gives the 190 a 160 deg/sec which is pretty impressive.
Flight Performance of Fixed and ... - Google Book Search

Great presentation - interesting that the 51 roll rate steadily increases with speed to point where it crosses over (exceeds) the clipped wing Spit, the Fw 190 and the P-47 at top speeds... but is chewed up in roll rates against all those at 250 kts.

I wonder why the 51 continually gets better as function of airspeed - not just better relatively but better quantitatively?

And does anyone want to do max rolls in an A-4 two or three times at 300 degrees/sec?

[Soren]

Great presentation - interesting that the 51 roll rate steadily increases with speed to point where it crosses over (exceeds) the clipped wing Spit, the Fw 190 and the P-47 at top speeds... but is chewed up in roll rates against all those at 250 kts.

I wonder why the 51 continually gets better as function of airspeed - not just better relatively but better quantitatively?

The P-51 featured great aileron control at high speeds, no doubt about it. The P-51's only problem at high speed was its elevators stiffening up considerably, making it feel like your driving a truck some -51 jocks say. This is one of the reasons that 109's sometimes succesfully pulled out of dives far earlier than the chasing -51 could. Now as to the FW190, well according to the pilots who flew it its controls were feather like & completely harmonized at all speeds, even at max dive speed, infact the controls were so light than one had to take care not to overstress the airframe at high speeds, esp. in pull outs.

However like I said the NACA chart isn't a valid source on the 190's roll rate as the a/c in question suffered from ill adjusted ailerons, something which causes permature stalling in turns and has a negative effect on roll rate, esp. as speed increases.

And does anyone want to do max rolls in an A-4 two or three times at 300 degrees/sec?

Very good point Bill, infact anything above 120 degree's pr. sec is way faster than needed and extremely disorientating.

[Glider]

I have done some rolls in a Hunter (360 deg/sec) and can assure you the first time around I was pretty confident that my brain was about 180 degrees behind the rest of my head.

[renrich]

The reason I question the 180 degree per second rate of roll in the FW is that in a test of the FW190A4 versus the F4U1 and F6F3 it was said that the rate of roll for the FW and F4U was equal. The F4U was a good rolling AC but I can't find any figures to justify a 2 second roll.

[FLYBOYJ]

However like I said the NACA chart isn't a valid source on the 190's roll rate as the a/c in question suffered from ill adjusted ailerons, something which causes permature stalling in turns and has a negative effect on roll rate, esp. as speed increases.

Soren, any information on how the ailerons were out of adjustment? - Looking at some schematics of the 190, aileron adjustment is a simple process, usually done at a turnbuckle or terminal eye, and if I remember weren't the 190's ailerons actuated with push tubes?

[davparlr]

The P-51 featured great aileron control at high speeds, no doubt about it. The P-51's only problem at high speed was its elevators stiffening up considerably, making it feel like your driving a truck some -51 jocks say. This is one of the reasons that 109's sometimes succesfully pulled out of dives far earlier than the chasing -51 could.

The Joint Fighter Conference gave the P-51 elevator control 5 out of 8 "good" vote (highest vote level) for force and 16 out of 19 voting "light" pressure. Effectiveness was rated "good" (again, the highest rating) by 19 out of 26 pilots (mostly Navy). There was also comments about the P-51 having good diving characteristics. There was no mention of elevator stiffening. Now they may not have tested the P-51 at extremely high diving speed, but I suspect they did a good job of yanking and banking and diving. Apparently the P-51 had very good elevator control over the great majority of the operational envelope (otherwise, I am sure the Navy would have loved to point it out).

[drgondog]

The Joint Fighter Conference gave the P-51 elevator control 5 out of 8 "good" vote (highest vote level) for force and 16 out of 19 voting "light" pressure. Effectiveness was rated "good" (again, the highest rating) by 19 out of 26 pilots (mostly Navy). There was also comments about the P-51 having good diving characteristics. There was no mention of elevator stiffening. Now they may not have tested the P-51 at extremely high diving speed, but I suspect they did a good job of yanking and banking and diving. Apparently the P-51 had very good elevator control over the great majority of the operational envelope (otherwise, I am sure the Navy would have loved to point it out).

51 elevator was only stiff in same regime as 109 and 190 and 47 and 38 and, and... namely in the initial compressibility range. Allegedly the 51 had lighter control forces than both the Fw and Me 109 at high speed, which may have contributed to perception of out turning both ships at high speed and altitude, and maybe reality based on stick forces contrasted with Lift Co-efficient.

The huge 'no-no' for recovering from a compressibility dive was keepa the han offa the trim wheel... it was ready to recover when you could move the stick.

What 51 piloys should absolutely not do is fast roll in the high speed dive - or pullout - that yaw force on the tail plus the wheel door uplock failure in the B/C is what broke the few Mustangs lost to Structural failure.

Roger on the Navy gleefully pick fun on Air Force

[renrich]

My source shows best elevators: F4U1D,F6F5,P51D,P47D. This is the 1944 fighter conference.

[Nikademus]

If you look at the number of kills/ losses in the South Pacific things really started to change at the latter end of 1942. I know JoeB may chime in here with info on "overclaims" by both sides, but the fact remains that the Japanese started loosing large amounts of fighters and most of them were Zeros. I don't think pilot rotation had anything to do with it, at least on the USAAF side....

The factor would be less apparant in the Pacific due to the smaller scale of the fighting, but it was still there. For example the battle of 7 Aug, 42 in which Tainen Air Group spanked the 3 CV CAP over Lunga can in part be attributed to recent rotations after the big Midway battle. In other words, some hard lessons had to be relearned the hard way as oft happened in the Desert.

After the campaign ramped up, yes, losses increased greatly but this was due more to the debilitating circumstances by which the Japanese accepted battle over the singular base of Lunga. Rotation on the US/USN side would have had less impact because they were fighting defensively over their own base and the scale of combat and losses did not see a mass of conscripts coming into the cockpits in multiple squadrons as in the larger scale battles/campaigns of the Western Desert. For the Japanese.....lack of rotation of key "Experten" would be felt more keenly in 43 once the pilot training system broke down under the stress.

[JoeB]

The factor would be less apparant in the Pacific due to the smaller scale of the fighting, but it was still there. For example the battle of 7 Aug, 42 in which Tainen Air Group spanked the 3 CV CAP over Lunga can in part be attributed to recent rotations after the big Midway battle. In other words, some hard lessons had to be relearned the hard way as oft happened in the Desert.

After the campaign ramped up, yes, losses increased greatly but this was due more to the debilitating circumstances by which the Japanese accepted battle over the singular base of Lunga. Rotation on the US/USN side would have had less impact because they were fighting defensively over their own base and the scale of combat and losses did not see a mass of conscripts coming into the cockpits in multiple squadrons as in the larger scale battles/campaigns of the Western Desert.

As I said in a previous post we might find examples of rotational policies affecting Pacific campaigns but that particular example is doubtful. Of the two USN squadrons losing planes in the Aug 7 '42 battle, VF-5: 5, VF-6: 4, (VF-71 didn't suffer any losses) VF-6 had been at Midway, the other sdn that had seen any real action at Midway, VF-3, had had its carrier sunk and the other two carriers hadn't been available for Midway. But anyway the Tainan Air Group, though it had never met USN fighters before, had seen more air combat in the Pacific War than any of the Zero carrier sdns and far more than any USN fighter squadron at that time.

But that combat also ended up mainly a one off statistical outlier. USN F4F combats v Zeroes before that, ie. Coral Sea and Midway, went 14:10 in favor of the F4F's, that one 2:9 in favor of the Tainan, but after that through the climax of Guadalcanal campaign (mid Nov '42) 23:22; in a mixture of carrier battles, G'canal defence, and convoy attack actions (see Lundstrom "First Team" s vols). Marine F4F's did somewhat better than that in a larger number of mainly G'canal defence missions (approx 90:70 see tables in Frank "Guadalcanal", air combat losses only but includes a few Zeroes downed by non-F4F's and vice versa). And no single combat before or after was as decisive for either side as that Aug 7 one.

The results don't actually vary that much from the typical Guadalcanal high altitude defence scenario to other scenario's, nor very noticeably after the Zeroes got bases closer to Guadalcanal, a lot of things were always changing. But rotational issues can largely be ruled out as an effect in the main defence of Guadacanal simply because the F4F force was an agglomeration of Marine units on considerably overlapping tours plus Navy units sent in ad hoc when their carriers were disabled; there wasn't any complete switchout of experienced units once there *was* much real experience. Likewise the Zero OOB was constantly changing and overlapping with analogous components: the prewar Tainan, newly activated units, carrier sdns detached to shore bases, plus a few carrier strikes met by landbased planes from Guadalcanal.

One definite and important Pacific War rotation policy in 1942 was most very high hour US naval pilots were rotated to training commands right after the war started, *before* seeing any combat, to jump start a huge expansion of the force. The average hours in USN F4F sdns dropped substantially in the first few months of the war, before they saw any combat with Zeroes at all. But it wasn't a matter of combat experience being rotated out since the USN had virtually none, in contrast to JNAF which had a lot from 1937-41 in China even when the Pac War started.

Joe

[FLYBOYJ]

The factor would be less apparant in the Pacific due to the smaller scale of the fighting, but it was still there. For example the battle of 7 Aug, 42 in which Tainen Air Group spanked the 3 CV CAP over Lunga can in part be attributed to recent rotations after the big Midway battle. In other words, some hard lessons had to be relearned the hard way as oft happened in the Desert.

You're citing one situation which I don't believe was the norm of the Pacific War. Look at some of the confrontations with the 9th 39th FS in Dec 1942 when practically the whole group were newbies, let alone transitioning into a new aircraft...

[FLYBOYJ]

Soren, any information on how the ailerons were out of adjustment? - Looking at some schematics of the 190, aileron adjustment is a simple process, usually done at a turnbuckle or terminal eye, and if I remember weren't the 190's ailerons actuated with push tubes?

I checked out a cut away of an Fw - it seems that ailerons were actuated with push tubes. Again I'd like to find out about this aileron misadjustment - if it was true it was an easy fix.

[Soren]

I checked out a cut away of an Fw - it seems that ailerons were actuated with push tubes. Again I'd like to find out about this aileron misadjustment - if it was true it was an easy fix.

Nope, it was actually a real pain in the a** to adjust correctly, go ask Crumpp he has all the details on this, and has experienced this pain in the a** procedure himself.

In the NAVY report the improper adjusted ailerons are mentioned as-well as that they had very negative effect on the turn performance and roll rate of the a/c.

Renrich,

The Navy tested their FW190 with ill adjusted ailerons, hence the results against the F4U & F6F.

___________________________


Will sure be a blast when the newly flying FW190's will be compared to other WW2 fighters

[FLYBOYJ]

Nope, it was actually a real pain in the a** to adjust correctly, go ask Crumpp he has all the details on this, and has experienced this pain in the a** procedure himself.

Again in what way? The process is basically the same on a number of aircraft - you might have to use rig boards to get the right deflection but I'm telling you we are not talking about something that would of been complicated so mechanics in the field would have a hard time doing it - I have my doubts about this - there are only so many ways to adjust a push rod and torque tube.

[Soren]

There's a reason for the Navy report mentioning this problem FLYBOYJ, and Crumpp has all the details, I'll sent him a message.

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