Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
To an extent, yes. The Germans figured out they could wait for the escort fighters (mostly P-47s) to turn around and then lay into the bombers. Obviously both planes were fighting in the PTO as well, but in the ETO it was the P-51 that took the fight to the enemy in a huge way. Unsurprisingly, it was not a turbocharged fighter.Well that worked right up until the P-47s stared flying relays. One group flying over the Dutch airfields, another flying with bombers and yet a third flying directly to the target area at economical cruising speed to meet up with bombers and escort them back. By the time the Mustangs began to show up in any real numbers the P-47s were being fitted with under wing drop tanks, while still shorter ranged than a clean Mustang a Range of 790 miles at just under 300mph wasn't too shabby. Late model Ds could carry even more fuel. Uneconomical to be sure but that might have had something to do with the size and weight of the P-47 and not necessarily the type of supercharger on the engine.
You are the one who keeps compalining about high altitude performance, An early P-47 D was about 20mph faster than a B model Mustang at most altitudes over 30,000ft.
The contemporary P-47D-10 in ETO at same time as P-51B-1 and -3 would not exceed the 51B in anything except rate of roll, which was superior. Dive and zoom is a toss up. Acceleration and turn and climb and level speed and range go to the 51B. The critical altitude of the D-10 was 25K, for the P-51B-1 29K so the advantage went to 51B-1 for all high altitudes..
Top speed with full internal load of fuel for the P-47D-10 w/Paddle props @2700 Rpm and 56Hg/WI was ~ 430 and went down hill as altitude was increased over 25K. The 51B-1 critical altitude was 29.8K feet and had top speed of 437 with full internal load and 50% higher climb rate..
By the time the P-47D-25 arrived, of course the high altitude performance increased to par with the 51B at 25K, slightly faster at 23K, when using the higher octane fuel at 70in Hg. Then the 47D-25 and newer increased speed above 30K as higher hp engines were installed
The P-51B-1 at 30K was faster than the 47D-25 at 30K at only 51" Hg and still had a better climb rate.
If you want to boost P-47D performance comparisons vs the P-51 you want to compare P-51D vs the contemporary 47's as it had the 1650-7 Merlin set for better performance (vs 51-1 and -3 and -5) at middle to 25K than the 1650-3 engine.
and then there was the range 'thingy' advantage which was stepped up again with the 85 gallon fuse tank mods until the production -5.
The P-47s were strictly relegated to Penetration and Withdrawal Support until the late model D's arrived in numbers and by that time most were going to 9th AF as the 8th was filling up with Mustangs to replace the P-38 ad P-47 Groups.
The premier 47 group, the 56th, virtually never went past Hanover/Kiel to the North and Stuttgart to the South until December 1944. Their last huge month was March - coincidently the start of the Berlin missions - and by that time the 4th, 354th, 355th, 357th and 363rd were equipped with Mustangs and the limit of 47 range was Dummer Lake.
Clay is right that LW tactics, pre Mustang, was to wait for the 47s to turn back. There were only two P-38 groups through February and they were easy to spot and therfore decide whether to engage or go somewhere else along a 100 mile bomber stream.
To an extent, yes. The Germans figured out they could wait for the escort fighters (mostly P-47s) to turn around and then lay into the bombers. Obviously both planes were fighting in the PTO as well, but in the ETO it was the P-51 that took the fight to the enemy in a huge way. Unsurprisingly, it was not a turbocharged fighter.
The contemporary P-47D-10 in ETO at same time as P-51B-1 and -3 would not exceed the 51B in anything except rate of roll, which was superior. Dive and zoom is a toss up. Acceleration and turn and climb and level speed and range go to the 51B. The critical altitude of the D-10 was 25K, for the P-51B-1 29K so the advantage went to 51B-1 for all high altitudes..
Top speed with full internal load of fuel for the P-47D-10 w/Paddle props @2700 Rpm and 56Hg/WI was ~ 430 and went down hill as altitude was increased over 25K. The 51B-1 critical altitude was 29.8K feet and had top speed of 437 with full internal load and 50% higher climb rate..
By the time the P-47D-25 arrived, of course the high altitude performance increased to par with the 51B at 25K, slightly faster at 23K, when using the higher octane fuel at 70in Hg. Then the 47D-25 and newer increased speed above 30K as higher hp engines were installed
The P-51B-1 at 30K was faster than the 47D-25 at 30K at only 51" Hg and still had a better climb rate.
If you want to boost P-47D performance comparisons vs the P-51 you want to compare P-51D vs the contemporary 47's as it had the 1650-7 Merlin set for better performance (vs 51-1 and -3 and -5) at middle to 25K than the 1650-3 engine.
and then there was the range 'thingy' advantage which was stepped up again with the 85 gallon fuse tank mods until the production -5.
The P-47s were strictly relegated to Penetration and Withdrawal Support until the late model D's arrived in numbers and by that time most were going to 9th AF as the 8th was filling up with Mustangs to replace the P-38 ad P-47 Groups.
The premier 47 group, the 56th, virtually never went past Hanover/Kiel to the North and Stuttgart to the South until December 1944. Their last huge month was March - coincidently the start of the Berlin missions - and by that time the 4th, 354th, 355th, 357th and 363rd were equipped with Mustangs and the limit of 47 range was Dummer Lake.
Clay is right that LW tactics, pre Mustang, was to wait for the 47s to turn back. There were only two P-38 groups through February and they were easy to spot and therfore decide whether to engage or go somewhere else along a 100 mile bomber stream.
Drgondog, i think we went back and forth on another thread a few months ago that brought comparisons of the P-51B and P-47C (might have been an early D).
It was determined that the 47 had a better zoom climb performance, out of level flight and even more so out of a dive. The P-51 had the edge in acceleration while the P-47 had better dive performance, however in most respects they were similar in performance.
Needless to say, the range of the Mustang is what gave its prowess. In a lot of ways i think its over rated as a fighter (IMO), but the remarkable thing is that the 51 was able to fly such long distances and still compete as a fighter plane.
Sorry, I was going by numbers from here: P-47 Performance Tests
See numbers for P-47D-10 dated 11 October 1943 and
http://www.wwiiaircraftperformance.org/mustang/p-51b-24771-level-blue.jpg
I see that I made a mistake in using the numbers from the P-51B-15 instead of the B-1.
I have read other places that the paddle blade props weren't fitted to new planes until the -20 or -22 aircraft. Of course older aircraft could easily have been refitted.
I am not trying to say that the P-47 was better than the P-51 but Mr. Allison's seeming contention that the AAF was helpless and or useless before the advent of the Mustang is wearing a bit thin.
Drgondog, i think we went back and forth on another thread a few months ago that brought comparisons of the P-51B and P-47C (might have been an early D).
It was determined that the 47 had a better zoom climb performance, out of level flight and even more so out of a dive. The P-51 had the edge in acceleration while the P-47 had better dive performance, however in most respects they were similar in performance.
You have to be careful on the timing and the model - the 47C was compared against the P-51A (as well as P-38F) and what you say is true.. but not when comparing the 51B-1 vs the 47D-10 in comparable timeframes
Needless to say, the range of the Mustang is what gave its prowess. In a lot of ways i think its over rated as a fighter (IMO), but the remarkable thing is that the 51 was able to fly such long distances and still compete as a fighter plane.
All opionions are worthy. The key is that the Mustang killed the Luftwaffe over Germany, not the P-47 and not the P-38 and not the Spit and not the Tempest and not the Yak and not the Laag.
All opionions are worthy. The key is that the Mustang killed the Luftwaffe over Germany, not the P-47 and not the P-38 and not the Spit and not the Tempest and not the Yak and not the Laag.
another key is that with out the Spitfire, (or YaK) we would've never needed the P-47 or 38.
with out the 47 or the 38, we wouldn't have needed the later Mustang.
Each plane had its place in the war.
All planes shot down the Luftwaffe, if you'd like to hype up the Mustang for doing it over Germany then so be it.
Not helpless, not useless, just not nearly as good as they could have been if they had not obsessed over turbocharging to the exclusion of multi-stage supercharging. I think better decisions could have led to a reliable P-38 in the ETO (which would have dramatically improved the survival rates of our bombers). Also better P-40 performance, especially in North Africa and probably in Asia versus the A6M Zero.Sorry, I was going by numbers from here: P-47 Performance Tests
See numbers for P-47D-10 dated 11 October 1943 and
http://www.wwiiaircraftperformance.org/mustang/p-51b-24771-level-blue.jpg
I see that I made a mistake in using the numbers from the P-51B-15 instead of the B-1.
I have read other places that the paddle blade props weren't fitted to new planes until the -20 or -22 aircraft. Of course older aircraft could easily have been refitted.
I am not trying to say that the P-47 was better than the P-51 but Mr. Allison's seeming contention that the AAF was helpless and or useless before the advent of the Mustang is wearing a bit thin.
another key is that with out the Spitfire, (or YaK) we would've never needed the P-47 or 38.
with out the 47 or the 38, we wouldn't have needed the later Mustang.
Each plane had its place in the war.
All planes shot down the Luftwaffe, if you'd like to hype up the Mustang for doing it over Germany then so be it.
BillS - please check your facts against the statement I made - "The Mustang killed the Luftwaffe over Germany" - that is where the battle for air supremacy was a.) lost before the Mustang, when all other fighters were either restricted from target escort by range (P-47, Spitfire, etc) or P-38's high performance issues in the F and G and early J's, and b.) where the LW was losing ~1000 pilots per month in March, April and May 1944.
If you think it is hype - look at the statistics of German aircraft shot down on Target escort versus Penetration and Withdrawal escorts.
Not helpless, not useless, just not nearly as good as they could have been if they had not obsessed over turbocharging to the exclusion of multi-stage supercharging. I think better decisions could have led to a reliable P-38 in the ETO (which would have dramatically improved the survival rates of our bombers). Also better P-40 performance, especially in North Africa and probably in Asia versus the A6M Zero.
It's not just that they should have known the turbo wouldn't be ready, they should have known that it would never fit in a smallish single engine fighter like the P-39 or P-40 because it was too large. That should have been obvious in 1938. I think they could have speeded up development with more funding.The Army may have been slightly obsessed with the Turbo-charger but not to the extent you seem to think.
They did test (pay for) at least one two-stage supercharged plane in 1939.
Work on the turbo for the Allison started in early 1933. GE (not Allison) got the $10,006 contrat to supply a turbo in 5 months. this early model was only supposed to provide sea-level air pressure to the engine supercharger up to 20,000ft.
By 1937-38 progress was not good enough for service work.
Allison did start work on a mechanical 2 stage supercharger on Nov of 1938. They did get experimental versions under test by 1940.
Now in 1940 they were still trying to improve on GE's rather poor performing superchargers, which Allison did. Just not the extent of improvement that R-R was getting per impellor.
as an example Allison was getting 1150HP at 3000rpm at 21,000ft using 49.7in of boost. This doesn't sound bad except for the fact that the engine was developing around 1630 Indicated HP. 147hp for friction, oil pumps, coolant pumps and other drives, aproxomatly 120 hp needed by the engine supercharger and about 220 HP needed to drive the auxilary stage. This early test engine also used a single speed drive for the aux supercharger. This was soon changed to a variable speed hydraulic drive. The first set up was intended for the Curitiss P-60 while the second set up was actually flown in Bell XP-39Es.
"The fuselage was lengthened by 1.75 feet to accommodate the longer -47 engine."
"Empty and loaded weights were 6936 lbs and 8918 lbs respectively, making the XP-39E the heaviest of all Airacobra variants. During tests, a maximum speed of 386 mph at 21,680 feet was attained, which was much better high-altitude performance than other Airacobra variants. An altitude of 20,000 feet could be reached in 9.3 minutes."
"About two weeks after its maiden flight, the first XP-39E crashed during spin tests on March 26, 1942."
These quotes are from:Bell XP-39E Airacobra
It took R-R 15 months to do the work on the two stage Merlin and they already had the Vulture supercharger sized for about a 1700HP air flow at altitude.
So in 1938 the Army would have had to figure out that the Turbo wouldn't be ready even 4 years in the future, and try to speed up Allisons work by well over one year to get any numbers into service by spring of 1942.
Allison would not only have to figure out the configuration but also substationaly improve basic compressor perfomance. Improving compressor efficency has the triple benifit of requiring less power to drive the supercharger for a given airflow (power) meaning more power to the prop. Lower heating of the charge temperature meaning higher air density and more power. And the lower charge temperature also offers either a higher boost limit or a greater safety margin from detonation. In a two stage system a more efficent compressor also means you can use a slightly smaller intercooler.
It's not just that they should have known the turbo wouldn't be ready, they should have known that it would never fit in a smallish single engine fighter like the P-39 or P-40 because it was too large. That should have been obvious in 1938. I think they could have speeded up development with more funding.
They can't. Neither can they say for sure that turbochargers will work just fine. The prudent thing would be to develop both turbochargers and superchargers and then chose the superior system based on operational performance.How could they know the trubo wouldn't be ready?
They can't. Neither can they say for sure that turbochargers will work just fine. The prudent thing would be to develop both turbochargers and superchargers and then chose the superior system based on operational performance.