p-47, p-51, p-38......

[drgondog]

BTW, i haven't looked at actual numbers, but i've read several articles that say the p-47 was the most successful fighter, when you talk kill ratios and targets destroyed. It could've been the sheer numbers of them, 15,000+, that were deployed in the war that might generate this opinion

The facts would support another conclusion - at least in the most competitive air to air combat theater of the war - the ETO. The 51 simply far outscored the 47 - largely because of it's combination of range and performance[

I still have some scrubbing to do but here are the 8th AF numbers (approximate of awards to losses)

47 air to air 1550 to 214. air to ground 739 to 214
51 air to air 3328 to 326, air to ground 3212 to 570

and the 47 was operational for more than 8 more months in the ETO
/B]



.......and there was also the p-47M and P-47N, that saw combat late in the war. The P-47J was an awesome plane, but was never massed produced because it was later decided it would save time to use the C and D airframes at a cost of a fraction of the performance....hence the M and N were born.

And the P-51H was as good or superior in level speed with all the other advantages in manueverability

You can have your opinion, as do I, i still believe the p-47 out dove the 51.

The difference is that I keep looking at Test reports that say otherwise?

You certainly are correct about a pilots account having some biased, but if the man flew both planes and still says the 47 could dive faster, i think their is some merit there. I'll see if i can't dig up another pilots account.

See what the air to air ratio was between Jugs and Mustangs in combat. They will be hard to find. Absent that Test reports and data are far more reliable than the 'pilots impressions' absent real comparative tests?

 

[billswagger]

Did the P-51H ever see combat in WW2???

 

[Vincenzo]

No, neither P-47N

 

[Magister]

No, neither P-47N

You're joking right?

 

[Vincenzo]

no, the P-47N don't saw combat in WWII

 

[Vincenzo]

ok i'm in wrong

 

[drgondog]

The first P-47Ns were delivered to USAAF in December 1944. The first P-51Hs were delivered to USAAF in February 1945.

The 47N was deployed to 318th FG at Le Shima in April 1945 and flew B-29 escort missions. I have not found any awards or claims of Japanese fighters so what is the definition of 'combat'? It was flying combat operations.

The reference to April 1945 is contained in Olynyk's Stars and Bars for history of 318th FG

Republic P-47N Thunderbolt

Both ships were delivered in multiple group strength before VE Day but the 51H was deployed to statesude interceptor swuadrons.

 

[Magister]

P-47N's at Le Shima

~318thFighterGroup.IeShima.html



Oscar Perdomo - Ace In A Day

Oscar F. Perdomo

 

[drgondog]

P-47N's at Le Shima

~318thFighterGroup.IeShima.html



Oscar Perdomo - Ace In A Day

Oscar F. Perdomo

Yep, I didn't look far enough. Perdomo's scores August 13th over Korea may have made him the last ace of WWII

 

[Magister]

Note that the performance figure for the "N" model is at combat weight but considerably below the approximately 21,000lb maximum loadout weight. This is also post 44-1 fuel as the horsepower of the "D" model is listed at 2,600.

 

[TheMustangRider]

I was about to mention Oscar Perdomo which by the sources I have read flew a P-47N in the Pacific and was the last American ace in a day of the war.

 

[billswagger]

I still think the P-47 was the faster diver.

The RAE include some details of a US dive test on the P-47. Starting at 27,700 ft the aircraft was put in to a steep dive, with angle rapidly approaching 67 degrees. By 19,000 ft the speed had reached Mach 0.861.
in which case, dive flaps were deployed and the plane safely pulled up, well intact.
It is suggested that the 51 may have dove equally as fast, but would begin to come apart. When the 51D (mkiv) achieved mach 0.85, the front lip of the wing began to peel back, and the plane developed a severe yaw. it was not considered a safe and flyable plane afterward.
I think numbers can be deceiving and that further explanation explains what plane was capable of making the fastest, most recoverable dive, with minimal damage to the aircraft. That would be the P-47....hands down.IMO

 

[drgondog]

I still think the P-47 was the faster diver.

The RAE include some details of a US dive test on the P-47. Starting at 27,700 ft the aircraft was put in to a steep dive, with angle rapidly approaching 67 degrees. By 19,000 ft the speed had reached Mach 0.861.
in which case, dive flaps were deployed and the plane safely pulled up, well intact.

That is interesting, where did you find the source?

It is suggested that the 51 may have dove equally as fast, but would begin to come apart. When the 51D (mkiv) achieved mach 0.85, the front lip of the wing began to peel back, and the plane developed a severe yaw. it was not considered a safe and flyable plane afterward.

Equally interesting - what did they mean by 'front lip'? The source of the Mk IV tests I presented to you from Mike Williams site (earlier in this thread?) described the shock wave and the bulge in the ammo cover door. Where can I find your reference to 'front lip'?
I think numbers can be deceiving and that further explanation explains what plane was capable of making the fastest, most recoverable dive, with minimal damage to the aircraft. That would be the P-47....hands down.IMO

Opinions are important but prolific - with the sources you mention above there is at least one reference to a higher dive speed in a controlled test above .83 for the Jug. Please direct me to the source?

 

[billswagger]

i had a feeling we could go round and round on this so rather than revisiting various articles and posts that i've read, i decided to get something straight from the horses mouth.

http://www.wwiiaircraftperformance.org/mustang/p-51d-dive-27-feb-45.pdf
This also backs what i said previously. See pg 2 C. and pg 3,4, and 5...although the entire record is a good read.


I'm still digging for information on the p-47, which ought to clear up its ability to safely out dive the P-51D(mkIV)....although i still hold a lot of merit for the pilots account i posted earlier.

 

[drgondog]

i had a feeling we could go round and round on this so rather than revisiting various articles and posts that i've read, i decided to get something straight from the horses mouth.

http://www.wwiiaircraftperformance.org/mustang/p-51d-dive-27-feb-45.pdf
This also backs what i said previously. See pg 2 C. and pg 3,4, and 5...although the entire record is a good read.

This is the report and website I directed you to for the MK IV (P-51D) Dive tests past .84M.. see post 19

I'm still digging for information on the p-47, which ought to clear up its ability to safely out dive the P-51D(mkIV)....although i still hold a lot of merit for the pilots account i posted earlier.

Good luck - I have been digging for comparable P-47 Dive tests from RAE or USAAF exploring critical mach dive limits.

 

[billswagger]

The problem i have with dive tests is that although the plane might have reached 0.84 - 0.85 mach, no pilot would ever dare to take the P-51 into that kind of speed, with out the fear of it falling apart.
...quoting from post 19
"7. Maximum Limit of Combat.- The airplane has been dived to a maximum Mach number of 0.85 and on several occasions to 0.84. In EACH CASE the pilots reported that the vibration became extremely heavy beyond 0.80. In EACH DIVE to 0.84 or above the vibration became so severe that the airplane was damaged. THE LEADING EDGE OF THE WING FLAP WAS BUCKLED BETWEEN RIVIETS, COOLANT RADIATOR CRACKED AND HYDRAULIC LINE BROKEN DUE TO VIBRATION on various dives to 0.84 and above. In extreme war emergency the airplane can be dived to a Mach number of 0.83 (400 m.p.h. Indicated Airspeed at 25,000 ft.), if a very gradual pull-out is made."



I think the P-47 was a plane that they dove with confidence, and with little detail on how fast they were actually going, all we can rely on are pilots accounts...P-47 Compressibility Dive - 510th Fighter Squadron
that suggest the p-47 could go beyond the speed of a P-51 in a dive.
I'm still looking for where i read that the 47 achieved 0.861 mach in a test dive. It was centered around the topic of dive flaps, but with all the information that comes across my laptop in a day, i'm having trouble finding that source, but i will find it.

Bill

 

[drgondog]

The problem i have with dive tests is that although the plane might have reached 0.84 - 0.85 mach, no pilot would ever dare to take the P-51 into that kind of speed, with out the fear of it falling apart.

But the test pilots without being chased, or chasing someone in a combat engagement repeatedly dove it to .84 to validate the safe limits of .75-.80.

The simple fact is that a lot of Mustang pilots were diving at Indicated air speeds in that range per the various Encounter Reports just on the Mike Williams website containg this report.

...quoting from post 19
"7. Maximum Limit of Combat.- The airplane has been dived to a maximum Mach number of 0.85 and on several occasions to 0.84. In EACH CASE the pilots reported that the vibration became extremely heavy beyond 0.80. In EACH DIVE to 0.84 or above the vibration became so severe that the airplane was damaged. THE LEADING EDGE OF THE WING FLAP WAS BUCKLED BETWEEN RIVIETS, COOLANT RADIATOR CRACKED AND HYDRAULIC LINE BROKEN DUE TO VIBRATION on various dives to 0.84 and above. In extreme war emergency the airplane can be dived to a Mach number of 0.83 (400 m.p.h. Indicated Airspeed at 25,000 ft.), if a very gradual pull-out is made."

I read that and I passed that on to you. Why read it back to me? How does that support your thesis? What you are repeating is similar to issues with all fighters, including even the me 262, for dives exceeding .80 M. The 51 was better than most (and particularly not experiencing 'Tuck Under' pitch issues at transonic transition.

I think the P-47 was a plane that they dove with confidence, and with little detail on how fast they were actually going, all we can rely on are pilots accounts...P-47 Compressibility Dive - 510th Fighter Squadron
that suggest the p-47 could go beyond the speed of a P-51 in a dive.
I'm still looking for where i read that the 47 achieved 0.861 mach in a test dive. It was centered around the topic of dive flaps, but with all the information that comes across my laptop in a day, i'm having trouble finding that source, but i will find it.

Bill

Bill - Until you find it, all you're doing is repeating opinions not supported by fact regarding the P-47 dive limits. BTW if the 47 had .86 M cited as the absolute limit, in comparison to a 51's .85 M - then at 15K that would be about 10 feet/sec difference. Less at higher altitudes

BTW - what methodolgy existed to get a dive speed to 3 digits (.861M) of precision?

The USAAF Report I quoted earlier From Ethell's Mustang said the 51 out accelerated the Jug (P-47D-10) in dive then maintained the lead.. suppose the 47 reached .86M as quick as the cleaner, faster accelerating P-51B-1.

How long would it take to catch up at 10 ft/sec?

 

[billswagger]

this is going beyond the scope of what i was intending to answer.

If you want to ignore the facts of what your own sources say that's fine.
To site a dive test that supports the P-51D reaching 0.84-0.85M is a misleading figure considering the plane was unsafe to fly afterward. This is where siting dive tests gets pretty harry, because one: the planes are tested at optimum conditions....two: they are pushed to extremes in these dives, to find where the limitations of the aircraft are.
IMO, the P-47 was a sturdier and much more reliable plane that was capable of a faster dive than the p-51D in combat. (that is, if you wanted to make it home afterward)
The P-51D was faster in many other ways, but could not safely dive past .80M
Obviously, it is a difference of opinion. You have sited the sources that support your end, as i have sited pilot's accounts and even looked further into your sources that support my opinion.
Maybe it is better to just agree to disagree.

(BTW critical mach of the P-47 was 0.83M. this sounds like a misprint. Maybe they mean that's the fastest it could dive.)

 

[drgondog]

this is going beyond the scope of what i was intending to answer.

If you want to ignore the facts of what your own sources say that's fine.
To site a dive test that supports the P-51D reaching 0.84-0.85M is a misleading figure considering the plane was unsafe to fly afterward.

Bill - how am I ignoring 'my own sources'? A.) did the Mk IV cited in the test bring the pilot home? B.) was the dive speed for that MkIV cited as .85?

I believe the answer is "yes"


This is where siting dive tests gets pretty harry, because one: the planes are tested at optimum conditions....two: they are pushed to extremes in these dives, to find where the limitations of the aircraft are.

We are still in synch, so?

IMO, the P-47 was a sturdier and much more reliable plane that was capable of a faster dive than the p-51D in combat. (that is, if you wanted to make it home afterward)

The problem Bill is that you have to continuously insert "IMO" when you talk about dive performance on the P-47. You cite references which state 'their opinion'.. but so far no set of planned tests, data reduction and dive speeds cited for the tests. Did I get this right? Or did I miss something?

The P-51D was faster in many other ways, but could not safely dive past .80M.

I believe that was close to the conclusion of the Mk IV test but the language was "Should NOT" vs "Could Not".. as the same 51 experienced (apparently) several dives at .84 and beyond - then the phrase Could not safely dive past .80M seems to be erroneous - or it would not have made it to test flight number 2. Am I missing something in the interpretation?

Obviously, it is a difference of opinion. You have sited the sources that support your end, as i have sited pilot's accounts and even looked further into your sources that support my opinion.
Maybe it is better to just agree to disagree.

My opinion about the dive speeds attained by a Mustang in a dive under controlled conditions, repeated, and reports written were extracted from published sources - and reproduced from actual tests performed by the RAF for the specific purpose of writing their own version of the Operating Manual for the P-51D.

You seem to cling to pilot first hand experiences in which their speed attained values are based on the instrumentation supplied by the manufacturer and only a close approximation of real IAS at velocities in the .55 M range. So far you haven't entered into evidence any theoretical transposition of those pilots readings of IAS into corrected TAS but you want to believe somehow that the P-47 was faster in a dive based on anecdotal recollections?

(BTW critical mach of the P-47 was 0.83M. this sounds like a misprint. Maybe they mean that's the fastest it could dive.)

No, Critical Mach is the Speed at which the Aircraft in question first experiences a transonic experience in the formation of a shock wave. Where do you find the figure .83 M cited as the critical Mach Number for the P-47?

Bill - I am happy to find out through you (or anyone else) that there are technical test agencies similar in function (RAF, USAAF, Republic Aviation, etc) that actually conducted controlled tests to obtain the dive speeds in a technically sound manner - and presented their repeated test results in a Report. This to me would an added value to my own knowledge. While crushing to my ego, there is a little part of me that has a 'happy smile'.

Unfortunately for me I am a trained and educated Aero Engineer and I struggle with 'first hand belief systems' not based on fact (guilty in some non engineering fields - like I stiil have illusions that our Republic will survive).

I am not denigrating your own belief systems - just contrasting why I am unmoved by your logic and facts so far.

 

[Magister]

Where do you find the figure .83 M cited as the critical Mach Number for the P-47?

Relevant to this discussion (post WWII testing):

Curtiss was able to obtain a P-47D-30-RE from the Air Corps. Fitted with one of several different "supersonic" propellers, Fisher undertook a long and risky flight test program that incorporated high Mach dives from high altitudes. Typically, Fisher would climb above 35,000 ft. He would then push over into a steep dive, allowing his airspeed to build beyond 560 mph (true airspeed). He would then execute a pullout at 18,000 ft. Several of these dives resulted in speeds of Mach .83. However, that was as fast as the P-47 could go.

Pushing The Envelope With Test Pilot Herb Fisher