Wasn't the P-51 the best escort fighter of the war?

[Reluctant Poster]

Attached is:

There is an inersting psection on rear fuselage tank

Also there are charts ta the end showing how the fuel is to be utilized during a mission

 

[Reluctant Poster]

No it doesn't. What is the internal fuel of the P-51B? You can quite easily load up a Spitfire with enough fuel in drop tanks to get to a place it cant fight back from. Why are the P-38M and P38J different in range with the same drop tanks? Could it be internal fuel? The escort escorted for part of a long range mission. They had to take off, form up as a squadron or group, then form up with the bombers wherever that was, cruise with the bombers at a speed suitable to engage the enemy, have enough fuel to engage the enemy for 15-20 minutes and then fly home.

Actually they used the relay system. Each fighter group was assigned to cover the bombers for a specific portion of the journey

 

[pbehn]

Actually they used the relay system. Each fighter group was assigned to cover the bombers for a specific portion of the journey

I know, that's what I posted.

 

[Reluctant Poster]

I know, that's what I posted.

Misread it

 

[pbehn]

Misread it

Here, with my bold for emphasis No it doesn't. What is the internal fuel of the P-51B? You can quite easily load up a Spitfire with enough fuel in drop tanks to get to a place it cant fight back from. Why are the P-38M and P38J different in range with the same drop tanks? Could it be internal fuel? The escort escorted for part of a long range mission. They had to take off, form up as a squadron or group, then form up with the bombers wherever that was, cruise with the bombers at a speed suitable to engage the enemy, have enough fuel to engage the enemy for 15-20 minutes and then fly home.

 

[Reluctant Poster]

Here, with my bold for emphasis No it doesn't. What is the internal fuel of the P-51B? You can quite easily load up a Spitfire with enough fuel in drop tanks to get to a place it cant fight back from. Why are the P-38M and P38J different in range with the same drop tanks? Could it be internal fuel? The escort escorted for part of a long range mission. They had to take off, form up as a squadron or group, then form up with the bombers wherever that was, cruise with the bombers at a speed suitable to engage the enemy, have enough fuel to engage the enemy for 15-20 minutes and then fly home.

I meant I misread your post

 

[pbehn]

I meant I misread your post

In peacetime, with no opposition, a P-51 could take off with maximum internal and external fuel in UK, fly to Berlin, fly back to UK (but not land) then turn around and fly to Berlin again and return to UK to land. That gives an idea of how much was used in "contingency", it wasn't a question of covering a distance, but of staying with the bombers while they were covering the distance.

 

[MiTasol]

This begs the question of why the RAF settled for 2 pitch vs constant speed in the first place, particularly in view of the last minute conversion to constant speed by DH technicians during the Battle of Britain. Hamilton Standard (which DH had the licence for) was making CS units well before the war. In fact Rotol used modified Hamilton Standard control units for their CS propellers.

Constant speed props require a governor and a govenor drive pad - both of which early engines of many brands were NOT fitted. You can only fit a CSU to engines that have the pad (and related internal gears etc) and on some engines that required an engine modification that usually included a reduction gearbox change.

 

[DarrenW]

Why did it take until 2012 to release the P-39N figures? I had not seen those numbers at any time before then. Excellent performance I thought. Thanks in advance.

Not to make light of the awesome achievement that is wwiiaircraftperformance, but sometimes the same data found there has been available to the general public for more than 50 years. For instance, the performance figures for the P-39N that you find so rare are also listed on page 447 of the very popular book, Combat Aircraft of the World, from 1909 to the Present (John W.R. Taylor), which was first published in 1969:

They are identical to what can be found here:

http://www.wwiiaircraftperformance.org/P-39/P-39N_FS-M-19-1487-A.pdf

 

[P-39 Expert]

Not to make light of the awesome achievement that is wwiiaircraftperformance, but sometimes the same data found there has been available to the general public for more than 50 years. For instance, the performance figures for the P-39N that you find so rare are also listed on page 447 of the very popular book, Combat Aircraft of the World, from 1909 to the Present (John W.R. Taylor), which was first published in 1969:

View attachment 581571

They are identical to what can be found here:

http://www.wwiiaircraftperformance.org/P-39/P-39N_FS-M-19-1487-A.pdf

True, this information has been available for a while but this is totally inadequate for any type of evaluation. Only with wwiiaircraftperformance.org did we get the full report with impressive climb numbers and speeds at all altitudes. Why did it take until 2012 for release of these figures? Just asking.

 

[drgondog]

Attached is:

View attachment 581543

There is an inersting psection on rear fuselage tank
View attachment 581544
Also there are charts ta the end showing how the fuel is to be utilized during a mission

Good examples of Bureaucrat efficiency. The 8th AF figured all this out in April 1944, 8 months before this report.

The 110gal externals pushed range to enable escort (and Combat) by the 355th FG on May 13, 1944 - 750 mi combat radius. The group policy was to take off on LH main, with 85 gal in fuse, use 20-25 of the 85 to climb out and then switch to external tanks for the remainder of the target leg to Posnan, Poland.

When dad led the last Shuttle mission, they burned 20 of the fuse tank, before switching to 110s. They engaged over Warsaw, shooting down four 109s and then completed mission to Piryatin Ukraine. He had 8 hours in his log and he was the last to land, knowing that the guys following had less fuel. IIRC they punched the 110s nw of Belin before switching to the fuse tank.

BTW, the elevator bob weight kit was installed on all 8th AF P-51B/C and D-5 and the first production run occured for the P-51D-10-NA in July 1944 timeframe.

 

[Greyman]

Why did it take until 2012 for release of these figures? Just asking.

Maybe my joke was a little obtuse earlier.

I'm sure a more detailed explanation is possible but the short answer is; 'Because its not their job'.

That site is researched, edited, coded, and curated in their spare time without a dime from any of us. Not to mention the web hosting fees.

If they want to spend the next two years of what spare time they have eating cheetos and playing nintendo instead of dealing with that site -- that's obviously completely up to them.

This clip is a wee bit harsh, but it's what comes to mind:

 

[Sturzkampfflugzeug]

It depends on where they are escorting, what they are escorting, and when they are escorting. As you may know, flak guns were everywhere along with airfields. This was a factor in whether the aircraft would make it through enemy lines. About ten percent of US bombers are shot down. Probably a slightly higher percentage of US fighters were shot down. If a flak position was just positioned right, it could potentially ravage a whole squadron. This also depends on the aircraft formations. In 1944, flak was responsible for about 3,501 American planes being shot down, enemy fighters had about 600 less in that time. Kinda impressive, right? And scary. So, to try to answer your question, yes, and no at the exact same time.

 

[tomo pauk]

It depends on where they are escorting, what they are escorting, and when they are escorting. As you may know, flak guns were everywhere along with airfields. This was a factor in whether the aircraft would make it through enemy lines. About ten percent of US bombers are shot down. Probably a slightly higher percentage of US fighters were shot down. If a flak position was just positioned right, it could potentially ravage a whole squadron. This also depends on the aircraft formations. In 1944, flak was responsible for about 3,501 American planes being shot down, enemy fighters had about 600 less in that time. Kinda impressive, right? And scary. So, to try to answer your question, yes, and no at the exact same time.

3500 aircraft down in 1944 makes for about 10 aircraft a day. Yes, every aircraft shot down meant a bad fate for crew members, but it was not that a great return of investment for 10000 (ten thousand) of Flak of 75mm and bigger deployed between Brittany and Berlin in 1944, and a similar number of light Flak.
IOW, not impressive vs. the numbers involved in ww2.

 

[P-39 Expert]

Maybe my joke was a little obtuse earlier.

I'm sure a more detailed explanation is possible but the short answer is; 'Because its not their job'.

That site is researched, edited, coded, and curated in their spare time without a dime from any of us. Not to mention the web hosting fees.

If they want to spend the next two years of what spare time they have eating cheetos and playing nintendo instead of dealing with that site -- that's obviously completely up to them.

This clip is a wee bit harsh, but it's what comes to mind:

Please, in no way was I disparaging that fine site or Mike Williams. At all. Just wondering where those figures had been for the last 65 years. Maybe they have the only copy.

 

[Reluctant Poster]

Good examples of Bureaucrat efficiency. The 8th AF figured all this out in April 1944, 8 months before this report.

The 110gal externals pushed range to enable escort (and Combat) by the 355th FG on May 13, 1944 - 750 mi combat radius. The group policy was to take off on LH main, with 85 gal in fuse, use 20-25 of the 85 to climb out and then switch to external tanks for the remainder of the target leg to Posnan, Poland.

When dad led the last Shuttle mission, they burned 20 of the fuse tank, before switching to 110s. They engaged over Warsaw, shooting down four 109s and then completed mission to Piryatin Ukraine. He had 8 hours in his log and he was the last to land, knowing that the guys following had less fuel. IIRC they punched the 110s nw of Belin before switching to the fuse tank.

BTW, the elevator bob weight kit was installed on all 8th AF P-51B/C and D-5 and the first production run occured for the P-51D-10-NA in July 1944 timeframe.

In fairness to those bureaucrats, they were not living in the age of the internet. They may not have had the full story of what the 8th was doing. Also the mission profile would have been different, particularly in view of the much higher performance of the B-29. I think the fact that they tried to duplicate the actual missions in tests was a good thing.

 

[Reluctant Poster]

Constant speed props require a governor and a govenor drive pad - both of which early engines of many brands were NOT fitted. You can only fit a CSU to engines that have the pad (and related internal gears etc) and on some engines that required an engine modification that usually included a reduction gearbox change.

My point is that the conversion was relatively simple. DeHaviland converted every Spitfire in front line service in the field, in 4 weeks. In another 4 weeks they converted the Hurricanes.

The full story is told here:
Stories of the Battle of Britain 1940 – Constant-Speed Propellers — Battle of Britain | 1940 | Reference | Spitfire Mk. I

 

[drgondog]

In fairness to those bureaucrats, they were not living in the age of the internet. They may not have had the full story of what the 8th was doing. Also the mission profile would have been different, particularly in view of the much higher performance of the B-29. I think the fact that they tried to duplicate the actual missions in tests was a good thing.

I agree on the mirror testing, but the existence of the elevator bob weight in all contemplated P-51D destined for Pacific should not have been a 'question'. That note would have been on the travelling documents for every Mustang - if installed by kit as the early -5s, or by effectivity on the T.O. Even a WW P-51B retired from combat in 1944 had the kit installed.

Notable is the fact that 90+% of all missions flown in escort of B-29s were flown with 160gal tanks.. Also notable is that the extremely long leg over water before reaching Jap fighter intercept possibility obviated complex fuel management processes. Contrast versus 8th AF where an intercept could occur after 100 miles from takeoff until well after D-Day.

 

[Reluctant Poster]

I agree on the mirror testing, but the existence of the elevator bob weight in all contemplated P-51D destined for Pacific should not have been a 'question'. That note would have been on the travelling documents for every Mustang - if installed by kit as the early -5s, or by effectivity on the T.O. Even a WW P-51B retired from combat in 1944 had the kit installed.

Notable is the fact that 90+% of all missions flown in escort of B-29s were flown with 160gal tanks.. Also notable is that the extremely long leg over water before reaching Jap fighter intercept possibility obviated complex fuel management processes. Contrast versus 8th AF where an intercept could occur after 100 miles from takeoff until well after D-Day.

Yes. One thing that I have always found intriguing is that the P51s flying B29 escort certainly violated the 70% rule of thumb. In fact they carried more fuel outside the aircraft than within. Mitigating that somewhat would be the fact that fuel consumption would be higher while carrying full drop tanks due to the extra weight and the increased drag. I know that Spitfire XIVs could carry their drop tanks into combat, did the P51s do so as well?

 

[drgondog]

Yes. One thing that I have always found intriguing is that the P51s flying B29 escort certainly violated the 70% rule of thumb. In fact they carried more fuel outside the aircraft than within. Mitigating that somewhat would be the fact that fuel consumption would be higher while carrying full drop tanks due to the extra weight and the increased drag. I know that Spitfire XIVs could carry their drop tanks into combat, did the P51s do so as well?

What is your source for '70%' rule of thumb? The load outs for P-38J, P-47D and P-51B were all over the place as far as external to internal fuel fractions were concerned. Simply stated they carried the largest external combat tanks available for long range tanks.

Correct on the extra drag penalty; For P-51B/D the drag penalty for optimal cruise w/110gal tank was a drop from ~300mph TAS to 260mph TAS at 25K ft altitude. The 160 gal tank was slightly more in net drag. Several posters have noted (correctly) that significant increases in external fuel capacity resulted in not so great increases in tactical radius.

During the period beginning July 1943 through May 1944, the combat tank capacity grew from 75gal to 150 gal for P-38H, (300gal internal), P-38J (300gal then 410gal) P-47D (305gal internally), P-51B (184gal then 269gal). For the P-38H w/150 gal the fraction is 1.00, for the P-38J w/150 the fraction is 73%; for the P-47D the fraction for 1x75 is 24%, with 108 it is 35%, with 150 it is 49%, for 2x150 it is 98%; For P-51B w/2x75 (no fuse tank) =81%, w/2x75 (w/fus tank) =556%, w/2x110) = 82%

The fighter pilots I knew (and read about) liked to (and did) eject their externals before engaging. That said my father shout down two 109s with a stuck 110 that wouldn't punch off. This was about 50mi ene of Berlin and he continued on to Stettin before turning back for home. Landed at Manston due to the drag of the empty tank.