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

[pbehn]

Resp:
Until Pearl Harbor, it would have been political suicide for the US Govt to enter into a second WW. Yes, the US had plenty of Irish, but there were English (my family), German, Italian, French, etc.. I can only speculate how the US could have entered the European war if Hitler had not first declared war on the US on 11 January 1942. Too much at play.

You mean formally enter with a declaration.

 

[Navalwarrior]

You mean formally enter with a declaration.

Resp:
Yes.

 

[Kevin J]

Resp:
Yes.

I was thinking more along the lines of the Irish saying, oh shit, the Germans have invaded England, and asking the Americans if they'd like access to the Treaty Ports that England had handed back in 1937.

 

[FLYBOYJ]

All I'm saying is we have benefit of hindsight. Looking back on all the P-38 development problems, delays, low Mach number etc., the Army would have been well served making a small number of P-38s and a much larger number of P-51s.

We do - the USAAF didn't. Look into the development problems, the reasons for delays and the low Mach number issues (that were basically unknown until the P-38 was developed) and the final fact that only a handful of these aircraft were expected to be built and I'd say the Army came out a head with what was known at the time. When Lt. Kelsey submitted the design spec that resulted in the P-38 do you really think he anticipated the need for adequate cockpit heating? Do you think he had the foresight to know we would be escorting B-17s over Germany during the winter months at high altitudes?

 

[AlfaKiloSierra]

The comparison will be made at 25000ft, the altitude of the B-17 raids.

Speed at 25000ft:
P-47D with -63 or -59 engine (cleared for 70" on June 24, 1944): 439 miles true speed http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-level.jpg
P-51 with -7 engine (cleared for 75" on April 29, 1944): 437 miles true speed http://www.wwiiaircraftperformance.org/mustang/na-p51b-150grade-level.jpg
P-51 with -3 engine (no data available for 75"): 440 miles true speed with 67", possibly faster with 75" http://www.wwiiaircraftperformance.org/mustang/fx953-level.jpg
(Note, the -7 engine was tuned for lower altitudes; at 25000ft the -3 engine is superior).
In this aspect, there is little to choose between the three airplanes; the difference in speed is not as great as allowable variation. Even weight change can cause a speed change of more than 3 miles.

Rate of Climb at 25000ft:
P-51, -3 engine, 67": slightly less than 2500 ft/min at 9200lbs of takeoff weight http://www.wwiiaircraftperformance.org/mustang/fx953-climb.jpg
P-51, -7 engine, 75": 2350 ft/min at 9680lbs http://www.wwiiaircraftperformance.org/mustang/na-p51b-150grade-climb.jpg
P-47, -63 engine, 70": 2400ft/min at 13600lbs http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-climb.jpg
(Note, this entire part can only be used as reference, as I have made it very clear that the weight for the three airplanes are different. Further, such weights are impossible to achieve in combat, as it takes large quantities of fuel to fly to Berlin and back. In most cases the P-51 would fight with full internal fuel except an empty fuselage tank if fitted; the same can be said about the P-47. The actual rate of climb depends heavily on the fuel load at which the airplane enters combat.)

Range:
P-47D-25 and on: 2100 miles at 10000ft (no data available for 25000ft; knowing the P-47's performance, it is safe to say that the range at 25000ft is at least somewhat longer)
P-47D-23: 1850 miles at 10000ft, same as above
P-47D-1 thru P-47D-22: 1700 miles at 10000ft, same as above
P-51 with fuselage tank: 2600 miles at 10000ft (no data available for 25000ft) www.wwiiaircraftperformance.org/p-47/p-47-tactical-chart.jpg
P-51 without fuselage tank and with -3 engine: 2250 miles
P-51 without fuselage tank and with -7 engine: 2290 miles
(Note: the P-51 data included the values of 1800 miles and 1850 miles for the P-51D variant. It is relatively easy to see that the large external tank available to the P-51B and C variant was not included. Due to the similarity in data otherwise, the P-51D can be inferred to have a range of 2600 miles when equipped with the external tank.)

There is very little to choose in the speed and rate of climb performance at 25000ft, any difference is more than likely made up for by the uncertainty of combat situations. The P-51 has an advantage in range, this is more pronounced if the fuselage tank is installed. P-51 has superior rate of turn and the P-47 has superior rate of roll at 25000ft, where the indicated airspeed is low. The P-51D equipped with the -7 engine substantially outruns the P-47 below that altitude; however this is not related to the discussion. The P-47 has a marked advantage in protection and firepower. For missions within the combat radius of the P-47 and altitude above 25000ft, the P-47 has slightly superior speed and possibly rate of climb; however, such a situation is unlikely to occur in Europe. In the Pacific, this role is filled by the P-47N (the only variant to out-range the P-51D). The P-51 is probably operationally more useful as an escort fighter than the P-47D due to the longer range, lower fuel expenditure and ease of maintenance.

P-51H and P-47N are, of course, not taken into consideration here because neither flew escort missions in WWII. The P-51H never saw combat and the P-47N attacked some ground targets near the end of the war.

 

[Navalwarrior]

I was thinking more along the lines of the Irish saying, oh shit, the Germans have invaded England, and asking the Americans if they'd like access to the Treaty Ports that England had handed back in 1937.

Resp:
It was important in more ways than one that the British held off an invasion via the 'Battle of Britian' in that the US would need a 'hunk of land' to operate from. If England had fallen, then a base in Ireland would have been difficult to secure with the Germans flanking Ireland on two sides; England and France. Just my two cents.

 

[fubar57]

Resp:
It was important in more ways than one that the British held off an invasion via the 'Battle of Britian' in that the US would need a 'hunk of land' to operate from. If England had fallen, then a base in Ireland would have been difficult to secure with the Germans flanking Ireland on two sides; England and France. Just my two cents.

 

[PAT303]

It is always interesting to weigh up the pros and cons, some people have some novel ideas as to why the Hurricane wasn't the best fighter, always fun to set them on the right path.

I have to agree with you, the RAF would have been better off with more Hurricanes instead of wasting time money and resources on the Spitfire Typhoon Tempest and Mustang.

 

[pbehn]

I have to agree with you, the RAF would have been better off with more Hurricanes instead of wasting time money and resources on the Spitfire Typhoon Tempest and Mustang.

At last some sense in the forum. In fact that is pretty much what did happen in 1940. The Spitfire was lucky to survive a review and if war came in 1938 not 1939 it possibly wouldn't have. The Typhoon was postponed, the Tornado was cancelled and the Mustang wasn't ordered until the crisis was over.

 

[Navalwarrior]

I have to agree with you, the RAF would have been better off with more Hurricanes instead of wasting time money and resources on the Spitfire Typhoon Tempest and Mustang.

Resp:
I suspect the loss was greater for the Lufwaffe in that a dogfight w the RAF used up precious fuel, causing ditching in the Channel on their route home to France.

 

[drgondog]

That is a good rule of thumb but for the P-51 and P-38 it gets a bit tricky as certain theaters had priority.
Merlin P-51s tended to go to Europe (NE Europe specifically) first.
P-51Bs start to show up in Italy and in the India/Burma/China theaters in April through June/July of 1944.
In the Pacific only 8 Merlin P-51s show up by Nov of 1944.

IMO the Mustang wasn't ready for deployment as an air superiority fighter until the Merlin engined variants came along.

Kevin J - I agreed your comment but limit agreement to high altitude escort/air superiority for ETO/MTO bombing campaigns. The P-51 and P-51A were deemed better than all the existing AAF (per Flight Evaluations at Eglin Field) fighters from SL to 20,000 feet - comparing 'in period' to P-40N, P-39Q, P-38G and P-47C. The majority of AAF ops in other theatres were below those altitudes. The P-51/P-51A would not have been better than P-47C and P-38G as interceptors for engagement above that altitude but there were a lot of air battles below 15000 feet and beyond the range of any US fighter save the P-38G equipped with ferry tanks as combat tanks not available until mid-1943.
.

 

[drgondog]

The comparison will be made at 25000ft, the altitude of the B-17 raids.

Speed at 25000ft:
P-47D with -63 or -59 engine (cleared for 70" on June 24, 1944): 439 miles true speed http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-level.jpg
P-51 with -7 engine (cleared for 75" on April 29, 1944): 437 miles true speed http://www.wwiiaircraftperformance.org/mustang/na-p51b-150grade-level.jpg
P-51 with -3 engine (no data available for 75"): 440 miles true speed with 67", possibly faster with 75" http://www.wwiiaircraftperformance.org/mustang/fx953-level.jpg
(Note, the -7 engine was tuned for lower altitudes; at 25000ft the -3 engine is superior).
In this aspect, there is little to choose between the three airplanes; the difference in speed is not as great as allowable variation. Even weight change can cause a speed change of more than 3 miles.

Rate of Climb at 25000ft:
P-51, -3 engine, 67": slightly less than 2500 ft/min at 9200lbs of takeoff weight http://www.wwiiaircraftperformance.org/mustang/fx953-climb.jpg
P-51, -7 engine, 75": 2350 ft/min at 9680lbs http://www.wwiiaircraftperformance.org/mustang/na-p51b-150grade-climb.jpg
P-47, -63 engine, 70": 2400ft/min at 13600lbs http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-climb.jpg
(Note, this entire part can only be used as reference, as I have made it very clear that the weight for the three airplanes are different. Further, such weights are impossible to achieve in combat, as it takes large quantities of fuel to fly to Berlin and back. In most cases the P-51 would fight with full internal fuel except an empty fuselage tank if fitted; the same can be said about the P-47. The actual rate of climb depends heavily on the fuel load at which the airplane enters combat.)

Range:
P-47D-25 and on: 2100 miles at 10000ft (no data available for 25000ft; knowing the P-47's performance, it is safe to say that the range at 25000ft is at least somewhat longer)
P-47D-23: 1850 miles at 10000ft, same as above
P-47D-1 thru P-47D-22: 1700 miles at 10000ft, same as above
P-51 with fuselage tank: 2600 miles at 10000ft (no data available for 25000ft) www.wwiiaircraftperformance.org/p-47/p-47-tactical-chart.jpg
P-51 without fuselage tank and with -3 engine: 2250 miles
P-51 without fuselage tank and with -7 engine: 2290 miles
(Note: the P-51 data included the values of 1800 miles and 1850 miles for the P-51D variant. It is relatively easy to see that the large external tank available to the P-51B and C variant was not included. Due to the similarity in data otherwise, the P-51D can be inferred to have a range of 2600 miles when equipped with the external tank.)

There is very little to choose in the speed and rate of climb performance at 25000ft, any difference is more than likely made up for by the uncertainty of combat situations. The P-51 has an advantage in range, this is more pronounced if the fuselage tank is installed. P-51 has superior rate of turn and the P-47 has superior rate of roll at 25000ft, where the indicated airspeed is low. The P-51D equipped with the -7 engine substantially outruns the P-47 below that altitude; however this is not related to the discussion. The P-47 has a marked advantage in protection and firepower. For missions within the combat radius of the P-47 and altitude above 25000ft, the P-47 has slightly superior speed and possibly rate of climb; however, such a situation is unlikely to occur in Europe. In the Pacific, this role is filled by the P-47N (the only variant to out-range the P-51D). The P-51 is probably operationally more useful as an escort fighter than the P-47D due to the longer range, lower fuel expenditure and ease of maintenance.

P-51H and P-47N are, of course, not taken into consideration here because neither flew escort missions in WWII. The P-51H never saw combat and the P-47N attacked some ground targets near the end of the war.

Two comments, maybe more:

The most interesting period to discuss air superiority relative to escorting B-17 and B-24s was October 1943 after 8th AF lost the air battle over Germany - to D-Day, when the destruction/Attrition of the LW was most critical. That said, the primary US escort fighters in any significant numbers are:
P-38J-10/-J-15 with and prior to the 55gal LE tanks; P-51B-1/-5 without 85gal fuse tanks (Dec 1943-early Feb 1944) and then with 85gal fuse tanks. 1650-3 exclusively until early April 1944, then a mix - but dominantly 1650-3 w/67" MP; P-47C/D-10 through December with R-2800-21, then add some D-11 and retro WI for the R-2800-63 power. Note that while 75" was approved for 44-1 fuel, the fuel didn't arrive in the ETO until late June.

For your cited performance data from Mike Williams fine site;
1. Note that none have wing racks during the tests until the P-51B-7 w/1650-7 was tested with and without racks and at 67" and 75" April 1944. The P-51B racks reduced speed by ~10mph at 67"MP at 29K.
2. The Take-off Gross weights in those tests are a.) at 100% max internal combat load at take off for their P-51B-5 test; 97% for the P-47-10 w/WI and -63 engine; c.) 98% for the P-38J-15.
Not a huge factor for speed on GW but huge for ROC. Additionally the P-47D (all) lost about 15-17mph with Wing pylons - ditto the P-38. So ALL the top speed cited are overstated, but the P-51B is the least overstated.

Next - there is Range and there is Combat Radius for planning purposes - dependent entirely on the fuel remaining internally after punching the external tanks and drawing down the fuel necessary fo 15min MP and 5min Combat Power.
1.) P-51B/D with 269gal = 375 mi; P-47D with 305gal = 230 mi; P-38J with 410gal = 275mi.

So - if you wish to make a point regarding the P-47D vs P-38J vs P-51B prior to D-Day, please consider the conditions of the flight tests vs operational consideration day to day over ETO.

Since there are no publicly available rich set of performance tests at full internal combat weight for either the P-38J (with fully functional -89/-91 above 20K in ETO conditions) or The P-47D with -63 engine you will have to resort to guessing to understand how badly those factors affected the P-38 and P-47D ROC figures - but they are significantly lower than the P-51B-1/-5 with 1650-3 engine at 30K. At reduced (equivalent percentage) internal fuel load, the P-51B performance superiority widens. Interestingly the drag of the external pylons is not so much a factor from the stated test flights because climb rates are at speeds in the range of 160mph where the relative Parasite drag of the pylons is less.

 

[DarrenW]

Not to be picky but the P-47D's speed and climb figures cited by AlfaKiloSierra were actually with wing pylons installed:

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-front.jpg

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-side.jpg

 

[michael rauls]

Just saw this. Great question.
While I've seen this take place on other sites, I was writing about this site (forum). And although I was not referencing member activity or tenure as it related to the points I wrote of, I would not draw any strong relationships between those two variables and any lack or proclivity thereof; especially since I've never paid attention to those aspects.

When I referenced the "Sage" ones, I was writing about the contributors who typically offer data from multiple archives that do not always agree, and their rich and balanced analysis as it pertains to the OP's original point(s) and/or question(s). They also help to refocus the sprawling "mini-debates" that may erupt from an increasing number of fighters and comparisons being pulled into the OP's topic. They tend to do this while also delving into needed topics such as aerodynamics, BFM, interviews, old stories from family and friends that were there, etc, all of which give needed context to understand the many elements and systems in place that affect the analyst being looked at. As a result they are often referenced and their opinion, data, and insightful post hoped/asked for.

These contributors do not need to be long time members, and I don't even know if they are, but they are wonderful to read. This in no way means that other posters have not offered great depth, data from diverse literature, and content expertise in engineering, fighter tactics and training (shout out to flyboy and others on that one), and aerodynamics.
As far as the bias and other topic references, they pertained to numerous threads that have come up over the years; whether it's Corsair vs Mustang (recent), the older Bf 109 thread(s), or threads about 'how would xx fighter have done if it had been in this theater', etc, etc. Such threads had wonderful premises and great content do I enjoyed those aspects. However these were also examples of what I write about that necessitated more and more sifting.

At times even a thread about a fighter's engineering specs, design features, or mission profile will devolve into numerous fighter comparisons were the topic seems to stray into proving what fighter was the best. lol.
In the end, there are a lot of great people here, and my intent was not to speak to anyone's character. Again, we all have biases; so there's nothing wrong with that. I was merely pointing out my frustration with how bias can and does taint the content, and for me, make it less enjoyable than it used to be to read.

My point in citing the "regulars" here was that they provide like 98% of the posts. Not that only there posts should be considered for reference just because. My bad for not making that clear.

 

[drgondog]

Not to be picky but the P-47D's speed and climb figures cited by AlfaKiloSierra were actually with wing pylons installed:

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-front.jpg

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-side.jpg

I wasn't clear that I was pointing out flaws in 11-43-May 1944 ETO performance data in reference to -63 engine with WI.

 

[Reluctant Poster]

Agree but remember the RAF mainly "area bombed." "You can't miss with a shotgun."

The Report on Oil wasn't addressing area bombing, it was an apples to apples comparison of the accuracy of USAAF and RAF on the same targets. Specifically the Leuna, Ludwigshafen-Oppau and Zeitz synthetic oil plants. These plants represent about a 1/4 of all bomb tonnage (29,956 tons) dropped on all synthetic oil plants.

For those that are interested I have found a complete copy of the report online:
Oil division final report. Oil division ...

 

[FLYBOYJ]

The Report on Oil wasn't addressing area bombing, it was an apples to apples comparison of the accuracy of USAAF and RAF on the same targets. Specifically the Leuna, Ludwigshafen-Oppau and Zeitz synthetic oil plants. These plants represent about a 1/4 of all bomb tonnage (29,956 tons) dropped on all synthetic oil plants.

For those that are interested I have found a complete copy of the report online:
Oil division final report. Oil division ...

I tried to scan the document and could not find anything that showed bombing methodology - precision vs area.

 

[drgondog]

The Report on Oil wasn't addressing area bombing, it was an apples to apples comparison of the accuracy of USAAF and RAF on the same targets. Specifically the Leuna, Ludwigshafen-Oppau and Zeitz synthetic oil plants. These plants represent about a 1/4 of all bomb tonnage (29,956 tons) dropped on all synthetic oil plants.

For those that are interested I have found a complete copy of the report online:
Oil division final report. Oil division ...

The RAF daylight raids were precision bombsight employed attacks. The RAF use of 2 and 4K pounders exclusively where USAAF used everything from incendiaries to 2K but mostly 500 and 1K bombs. The damage assessment favored RAF use of heavier bombs

 

[Reluctant Poster]

The RAF daylight raids were precision bombsight employed attacks. The RAF use of 2 and 4K pounders exclusively where USAAF used everything from incendiaries to 2K but mostly 500 and 1K bombs. The damage assessment favored RAF use of heavier bombs

Read the report. The RAF raids were at night

 

[Navalwarrior]

Kevin J - I agreed your comment but limit agreement to high altitude escort/air superiority for ETO/MTO bombing campaigns. The P-51 and P-51A were deemed better than all the existing AAF (per Flight Evaluations at Eglin Field) fighters from SL to 20,000 feet - comparing 'in period' to P-40N, P-39Q, P-38G and P-47C. The majority of AAF ops in other theatres were below those altitudes. The P-51/P-51A would not have been better than P-47C and P-38G as interceptors for engagement above that altitude but there were a lot of air battles below 15000 feet and beyond the range of any US fighter save the P-38G equipped with ferry tanks as combat tanks not available until mid-1943.
.

Resp:
drgondog, do you have a date of the above Flight Evals at Eglin Field? I'm thinking May 1943. Thnx.