XP72 "superthunderbolt" vs TA152 How would they stack up?

jim said:

Mid war 109s suffered from aerodynamic point of view as well. Simply from middle 42 to early 44, 109 received not one significant improvement in any way, engine or airframe or controls.
In WW1 germany also lacked competitive high power engines but still ,by excellent work in airframes and wings , created aircrafts fully equal (if not superior ) to the alleid fighters and pilot friendly (Fokker DVII , DVIII, Siemens DIV) .But in DVII case, it was MvR who had the final word how should be build. In WW2 aircraft programs was a chaos between Udet, Milch, RLM , Goring, aircraft companies, Hitler, political friends etc...Somewhre among them was the General der Jagdflieger but without any important impact.
I dont know if the Spitfire was overall better but certainly had a more orthodox and logical evolution

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The Me 109G1 and G2 weren't too bad from an aerodynamic point of view, they didn't have the gun bulges yet and retained the retractable tail wheel and such refined aerodynamic features which came across from the Me 109F however with the DB605A engine restricted to 1.3 ata (about 1350 metric hp) the Me 109 was significantly behined the Merlin 61, Merlin 66 and Merlin 70 that equiped contemporary Spitfire IX's and VIII and offered up 1500-1720hp at a higher altitude.

From the Me 109G2 onwards all sorts of aerodynamic degradations progressively appeared in the G3, G4m G5, G6: cowling bulges when the 13.2mm guns replaced the 7.62's, wing bulges when the main wheels were enlarged, loss of the retractable tail wheel when it was enlarged, larger more draggy aerials.

The result is that the speed from 400.5mph for and Me 109G1 to 387mph for an Me 109G6. Speed of the Me 109G-6 went back up to 397mph in the second half of 1943 when the engine was rated to 1.42ata boost after faltering attempts.

Had The Me 109G6 retained a retractable tail wheel and had the gun bulges been engineered to be smooth (as was possible and even flight evaluated) the Me 109G6 probably would have made 397mph at 1.3 ata and 410 at 1.42 ata or thereabouts.

Had the engine produced 1.42ata from the begining it also clearly would have been much better.

It's hard to blame German engine manufacturers given the fuel they had to use and if the DB601A1a vs DB601N is a worthwhile comparison then about 10% more power could be extracted from the early 96/115 grade C3 fuel as opposed the 87 grade B4. The BMW 801 did rather well so its not quite right to say they had no good engines.

To me it seems compromising the the airframe (gun bulges, loss of retractable tail wheel) as opposed to actually improving let alone maintaining aerodynamic qualities was a mistake. It would have been worth waiting a few months longer for a proper solution.

By accepting compromised solutions tooling and parts promulgated throughout the manufacturing system and became even harder to achieve a proper modification.

Contemporary Spitfires had 10-20mph more speed and 10%-15% more power being able to sustain 408mph , this even after the DB605A1a had been released to 1.42 ata.

Engine power didn't improved till the DB605AM of March 1944 which offered around 1700hp, aerodynamic improvements came at the same time, but only on the versions with the enlarged supercharger of the DB605ASM which offered the same power but at higher altitudes. This is when the Me 109 restored its competiveness but it still wasn't enough as the new engines still went into airframes with the same drag issues and much potential was wasted.

I think this came at a considerable cost in pilot attrition.

GregP said:

By the way davparlr, your location says "Southern California." Where are you located? I'm in Rancho Cucamonga.

Any chance of you making out to Chino some Saturday to see the Planes of Fame Museum? Like to meet you.

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I live in Carson about three mile south of the Goodyear blimp.

I've been to Chino several times even went to the May airshow a couple of years back. I was absolutely amazed. I never thouht I would see some of those planes much less see them fly. I am planning on taking my son some Saturday. I would be delighted to meet you. You work there, right?

Actually no. I am a volunteer at the Planes of Fame and do aircraft restoration work on Saturdays. I work for Joe Yancey building Allison 1710 V-12 engines.

If you want a neat trip, come any Saturday and ask where the restoration hangar is. Once there, ask for Greg Pascal. I'm there every Saturday working on the Bell YP-59A Airacomet. I'd be happy to show you around. Lately I have been helping out the guys on a North American O-47 and T-6 cowling repair (just worn out ... so new cowling formers are needed and almost completed).

If you want a neat second trip, we can take a 25-minute ride to Rialto and I'll show you Joe Yancey's Allison shop. We have about 100 Allison engine ready for restoration and you can see them whole, in pieces, and in various states of assembly, including a complete, ready-to-run left turning engine from Lefty Garnder's White Lightning P-38 on a run stand. It is Joe's airshow engine.

The Museum opens at 9:00 am. We have an event on the first Saturday of every month. The featured aircraft on the first Saturday of April is our P-38 Lightning.

Best regards, - Greg

GregP said:

Actually no. I am a volunteer at the Planes of Fame and do aircraft restoration work on Saturdays. I work for Joe Yancey building Allison 1710 V-12 engines.

If you want a neat trip, come any Saturday and ask where the restoration hangar is. Once there, ask for Greg Pascal. I'm there every Saturday working on the Bell YP-59A Airacomet. I'd be happy to show you around. Lately I have been helping out the guys on a North American O-47 and T-6 cowling repair (just worn out ... so new cowling formers are needed and almost completed).

If you want a neat second trip, we can take a 25-minute ride to Rialto and I'll show you Joe Yancey's Allison shop. We have about 100 Allison engine ready for restoration and you can see them whole, in pieces, and in various states of assembly, including a complete, ready-to-run left turning engine from Lefty Garnder's White Lightning P-38 on a run stand. It is Joe's airshow engine.

The Museum opens at 9:00 am. We have an event on the first Saturday of every month. The featured aircraft on the first Saturday of April is our P-38 Lightning.

Best regards, - Greg

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Thanks. I sent you a private message with my email address. I would love to see those places.

davparlr said:

I live in Carson about three mile south of the Goodyear blimp.

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Get a lot of shade by goodyear overcast do you?

GregP said:

...If you want a neat trip, come any Saturday and ask where the restoration hangar is. Once there, ask for Greg Pascal. I'm there every Saturday working on the Bell YP-59A Airacomet.

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Greg,

At the risk of a reprimand for departing from the thread's theme... What engine are you using in the retored Airacomet? Surely not the original GE I-16?

Hi oldcorw,

We are using two overhauled General Elexctric I-16 engines that have been fitted with mnodern bearings. I thought all the lines around the I-16 were either fuel or oil, but there is one line that has a mixture of compressed air and oil mist, and it is played right onto the bearings to keep them lubricated. We resotred the engines in the 1990's and have had them pickled since then. When we were done, they started and ran just fine and made rated thrust.

We have one "spare," and it will likely go into our Ryan FR-1 Fireball when we get through with the YP-59A. We recently (well, twp yeara go anyway) obtained a copy of the Ryan Fireball airframe maintenance and repair manual, and it is a real candidate for reatoration to flight status in the future ... with an I-16 (later called a J-31).

OK, end of departure from thread. If we want to discuss this further, let's start a new thread, OK?

jim said:

Mr GregP
1) Its an extraordinary claim that a piston engine airplane with maximum speed 503mph could cruise at 490mph. In my opinion is totaly unacceptable
2) Ta 152 wing profile provided extra edge in agility
3) In a quiq search in Internet found max speed pf 480-490mph. In "P47 in action" indeed says 503mph
4) XP 72 would be in action the earliest spring 45. Jumo 213 EB or DB603LA would be the current choises for the TA of around 2300hp
5)Ta 152H-1 normal take off weight 4625 Wing area 23,5 m2 2050 hp = 196 kg/m2 2,25,kgr/'hp
XP72 normal take off weight 6560kgr wing area 27,9 m2 3000 hp = 235 kgr/m2 2.18 kgr/hp
Ta 152 also has smaller frontal area and is generaly smaller. These evidences do not indicate a big diference in rate of climb
5) Ta 152 s mechanicaly driven supercharger was faster reacting during dogfights than turbos . ( without Mw 50 or Gm1 in use)
Performance wise these aircrafts appear quite similar and more powrful engines (3500hp for XP 72 and 2400/2600/2800 for the Ta) would not change the balance alot. Ta always would be more agile and cheaper .Xp72 more numerus
I used wikipedia for xp72 data

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Try looking at: Republic XP-72 Super Thunderbolt High-Altitude Fighter - History, Specs and Pictures - Military Aircraft

Author there reports the 480mph speed was in flight testing WITHOUT the turbos engaged! Keep in mind we're talking about a 3500hp aircraft. The XP-47J flew 504 in level flight.

They estimated top speed with the contra-rotating props at 550mph. Though neither prototype broke 500mph in the flight testing that was done.

mikeyz99 said:

Author there reports the 480mph speed was in flight testing WITHOUT the turbos engaged!

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Given that the R-4360-13 engine the XP-72 was powered by was fitted with a supercharger (a single stage one at that), instead of a turbocharger, that's entirely possible...

There are a lot of conflicting reports about the top speed of the XP-72. Three general speed brackets are usually given: 480 or 483 mph with "broken" supercharger at sea level or 3200 ft. 490/493/494 mph at 25,000/33,000/33,500 ft with a two stage, fluid coupled supercharger. 502/504/505/507 mph at 33,000/34,500 ft with a turbosupercharger.

The higher two figures are probably projections, for various iterations to be fitted with R-4360-19s. Bodie's 'Thunderbolt' has a test pilot quote that states the aircraft never broke 500 mph in level flight.

mikeyz99 said:

They estimated top speed with the contra-rotating props at 550mph. Though neither prototype broke 500mph in the flight testing that was done.

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Top speed with contra-rotating props is usually lower not higher. Look at the various late-war Spitfire/Spiteful prototypes for examples.

The Republic estimate of 550 mph was the estimate of the upper limit that they could take the airframe. 505 mph was projected for a 4000 hp version, powered with a R-4360-19 with an infinitely variable 'fluid coupled' supercharger. 540-550 mph was also bullied about for a turbocompounded version of the P-72.

Jabberwocky said:

Given that the R-4360-13 the XP-72 was powered by was fitted with a supercharger (a single stage one at that), instead of a turbocharger, that's entirely possible...

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The XP-72 was fitted with an auxiliary supercharger - mounted in the rear, where the turbo was on the P-47 and driven by an extension shaft. It may, or may not, have been connected.

The R-4360 would require two of the turbo systems that the P-47 carried - two C-series turbos plus the associated intercoolers and plumbing.

This is what Bodie's book on the P-47 says about the XP-72 series:



Bodie says Carl Bellinger got to 480 mph at sea-level without using War Emergency Power, and the engine fitted was not the definitive -19 series with the "remote blower" unit. There has to be some doubt about this claim; nevertheless the XP-72 was capable of flying faster than the production Ta-152. Both were probably close to the limits of piston-engined fighter performance without the development of radically different propeller technology. Gross weight of the XP-72 was 14,760 lbs; production aircraft would probably have been heavier.

(The XP-47J flew at 505 mph, according to Bodie, "at a density altitude of 34,450 feet with 2,730 hp." During official trials it reached 484 mph @ 25,350 feet and 2,770 hp; weight = 12,400 lbs).

Siegfried said:

The Ta 152 was running well ahead of the XP-72 in terms of timeline.

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While Siegfried stated that the "timeline" of the Ta-152 was well ahead of that of the XP-72, he's wrong on that score: the proper Ta-152H prototype, the Fw 190 V-33/U1, didn't fly until July 1944, while the C series prototype, Fw 190 V-21/U1 first flew in November 1944. The first XP-72 flew in February 1944 and the second in June.

Aozora said:

Bodie says Carl Bellinger got to 480 mph at sea-level without using War Emergency Power, and the engine fitted was not the definitive -19 series with the "remote blower" unit. There has to be some doubt about this claim;

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480mph at sea level....very unlikely.

The whole point of the remote supercharger was to maintain the CoG as per P-47 (which had the rear mounted turbocharger). If it wasn't fitted there must have been quite a bit of ballast.

This report has the maximum speed at sea level of a P-47D as 333mph with 2210hp.

For an XP-72 to do 480mph at sea level would require over 6600hp assuming the same drag as a P-47D, or a 55% reduction in drag with the early version R-4360, rated at 3000hp.

Comparisons are entertaining, and you always end up learning something previously unknown. Rgeardless of conflicting data from biased sources, can it be categorically stated that the Ta 152 was the fastest operational piston driven fighter of WW2? There will always be examples of aircraft that achieved higher top speeds, but to the best of my knowledge, none of these saw combat. The developmental potential of the Ta 152 had not been achieved by 1945, but the advent of the Jet age made any more progress in piston driven fighter aircraft academic. From all accounts, considering the the chaos that was Germany at the time, it was a remarkable achievement.

Good point, Pattern14.

The arrival of viable turbojets made the horendously-complex large piston engines obsolete, especially in light of the difference in maintenance requirements. I'd put up with engine changes in jets before i'd ask to change 56 spark plugs.

The Ta-152H might have been the fastest combat aircaft of WWII, though the P-47N wasn't behind by enough to matter in an encounter. 467 mph versus 472 isn't enough to hang your life on, even if your name is Harry Houdini. In point of fact it was obsolete with the arrival of the jets, but this fact ahd not caught up to reality by mid-1945, and the piston fighters were still a force to be respected, especially in operations with any significant range requirement where the new jets were simply not a factor yet.

In the war the Ta-152 had a below-average success with 7 victories versus 4 losses in one month of combat, but the potential was clearly there had the war gone on. The P-47N DID make the war and did make combat, but not in Europe. It's a what if and the 43 or so Ta-152's that made combat could never have hoped to comtend with the 1,816 P-47N's produced.

But one on one it would have been very interesting for both pilots. It would have been great to do that in mock combat, but it would not be worth anyopne's life to find out for real, at least to me. We know what happened and Ta-152 development was aborted before any significant progress was made in debugging the first models. I'm sure it could have been developed since the planes that were fielded were the first production variants and were really just a rather large number of prototypes with no spare parts.

Conversely, the XP-72 could also have been developed into a first-rate combat piston fighter ... but, by then, the P-80 could have been in squadron service. Of course, it would NOT have made ot up to 50,000 feet, but the Ta-152 would be the generally lower-performing mount of the two.

Since I brought in the P-80, the Germans would probably have fielded the Me 262 instead of the Ta-152 themselves, and we'd have had a jet war, with the pistons fighting each other, and the P-72 vs. Ta-152 could have happened if the war had gone on for some time. Thank heavens it didn't.

I don't believe this comparison could ever really be addressed with any degree of what might be called accuracy. If the data avilable for the Ta-152 isn't exactly great, think of how little real information is out there for the XP-72! As I stated about 8 pages ago, I think the two would have been a good matchup, but the pilots would make the difference.

I think with even pilots the XP-72 would win a dogfight, but it would be close for sure. And if the 152 pilot is even marginally more skilled, or vice versa, that would be the decider. Outside of a dogfight, the 72 would be better suited for ground attack obviously (4x 37mm would tear all but the mighty Tiger II to shreds), but the 152 would be a better bomber interceptor due to its speed and altitude, and thats what both sides needed respectively, the USAF needed multirole, the LW needed bomber interceptors.

The 37mm M4 cannon had a MAXIMUM armor penetration of 1 inch at 500 yards.
The Tiger 2 had a MINIMUM armor thickness of 25MM ( that real close to 1 inch) and maximum armor thickness of about 7 inches in forward areas and the turret.
That doesn't sound like a formulae for shredding the Tiger IMO.

All the 37 mm cannon would really have to do is disable one tread and it would then be a sitting target waitning to be dispatched. Certainly a still-sangerous target, but a target nevertheless.

A tank was NOT a good place to be when aircraft with big guns were about and snoopping around for someplkace to expend unsued ammunition.

In American Combat Planes by Ray Wagner (1980) the XP-72 is shown with a top speed of 490 mph, 300 mph cruise, 20,000 feet in 5 minutes. These data are much more in line with what I expected from a prototype with the high altitude systems not figured out yet.

The need for the P-72 tended to fade as the R-2800 was brought even higher power levels.

"Two XP-72 prototypes were ordered on June 18, 1943"

P-47ds with water injection were pulling 2300+hp in Oct. 1943. Later Versions went over 2500hp and the M and N versions could hit 2800hp with WEP which is getting close to the 3000hp offered by the R-4360. Granted the R-4360 is at military power and not WEP but BOTH the 2800hp R-2800s and the early R-4360s were a bit lacking in reliability. The R-4360 may have been running behind schedule also.

Just ordered a book from amazon on the Ta 152, by Dietmar Harmann. Going by the reviews, it is THE book to get on this plane, in terms of factual content. Then again, maybe his mates reviewed it favourably for a case of fine German beer' so I guess I'll have to read it for myself. Because I usually spend time in the R/C modelling forums, it never fails to amaze me on the amount of misinformation and urban myths about advanced German aircraft. A lot of the stuff is often just outright fabrication. " virtually unstoppable Me 262's", Arado Ar234 immune to allied fighters, He 162's with combat kills etc etc. The vast majority of us were not there when it happened, so we have to rely on historical evidence and recorded statements and military records. As a kid in the 1960's and 70's, all I had was library books and monthly magazines from the local newsagent, with stories and tales of WW2 air combat and such. Now we have an information overload on the net, where Wikipaedia will provide information on just about anything, enabling anyone to become an armchair expert. Such is progress.