Bf-109 vs Spitfire vs Fw-190 vs P-51

[davparlr]

1.) Two were built, both were prototypes.
2.) It wasn't ready.

It is interesting that you consider the Ta-152 as being ready when it first began combat operations only months after the first flight of the prototype in August of '44, which crashed along with other prototypes (of course this is what you consider a non-rushed development cycle) while you make an unsupported comment that the P-72, whose prototype was flown in Feb. '44 and in production, would not have been ready if needed. Oh, I forgot, it is not German.
Considering the fact that the P-72 was basically a re-engined P-47 and the Ta-152 had a highly modified fuselage, new wing, and a new engine, I suspect the P-72 prototypes were more ready than the Ta-152 was when it first entered combat.

3.) By the time it would've been ready it would've already been outperformed by German a/c.

Not by any propeller driven aircraft. To beat that 480 mph airspeed at SL, any prop plane you named would have had to have one heck of a new engine, sporting probably a 50% increase in power.
Of course, all these planes were obsolete by this time.

1944 was the beginning of the jet age, and the Germans were the leaders in this field.

Undeniable. However, the allies were catching up fast. The Germans would have leaped ahead with the use of swept wings, but the allies would have caught up in a year.

Nope, not at all. The Me-262, He-162, Ta-152 Fw190 D-12 13 were NOT could-have-been a/c.

Me-262-outstanding aircraft and would have been competitive for several years.
He-162-marginal performance for a jet. Not much advantage except for producibility. Not much faster than the Meteor, P-80 being much superior. It probably would have killed more inexperienced German pilots than allied pilots. Single engine reliability of early German engines had to be a nightmare.
Ta-152, Fw-190D-12 13. These are not super performers above latest allied aircraft (P-51H, P-47M/N, F4U-4, British?). I would bet even with a new engine (I have no performance figures on those engines). The allies, except for the Navy, had moved on to jets (generating loss of interest in the P-72, XP-56, and others).

But if you want to discuss prototypes could-have-been's I told you that the Germans were ready to put the Jumo 004E Jumo 213EB into production, and these were NO prototypes, these were finished designs.

I don't anything about jet engine development, but I think others have argued this with you.

Furthermore the Go229 production design was finished and the a/c was ready to enter production, two production examples were already 90% complete.

It amazes me how you assume that all German engineering is perfect and all proposed aircraft behave as planned and all development proceeds flawlessly. The Go229 was probably five to seven years away from combat capability or cancellation. Zero lateral stability was an obvious problem, requiring constant pilot attention to prevent the aircraft from becoming a Frisbee. Close coupled pitch stability also would have to be investigated thoroughly. Stall characteristics – unknown. On and on. Going into production with only one unsuccessful flight was massively risky. I suspect the Go229 would not have been a successful fighter without modern computerized flight controls.
Having said that, it was an amazingly advanced design, just too far ahead of technology.

Also the first P.1101 prototype was 90% complete,

This aircraft had potential to be the first swept wing aircraft the allies would have faced, and could have been quite successful in the fixed wing sweep mode. With in-flight variable wing sweep, however, success was several years off.

and the Ta-183's design production plans were finished.

Again, from plans to combat is often a rocky road. Based on Tank effort in Argentina, this design was several years away from combat capability. In fact it seems that the Mikoyan design team was more capable of solving the problems of this design than was the Tank team.

Depends how you define significant challenge. Fact of the matter is that with the Jumo 213EB there was no Allied prop job in development which could match the Ta-152's performance, and with the Jumo 213J it was far superior in every parameter of performance from SL and up

All, hypothetical. I know nothing about these engines, but unless they generated 2300 hp or greater would it approach the P-51H at low altitude, although, depending on the power profile, could lower the altitude where is was superior. And, unless it generated 3000 hp would it approach the P-72. And, how much Q loading would those long wings withstand, also, their drag performance is not the best for high Q flight.

.

BUT, like it had always been, these new German a/c would be out-numbered the day they took to the sky, and seeing that both fuel experienced pilots was in very short to no supply there really was no a/c which could save the Germans from the inevitable defeat.

True. At this time, the allies could have had only P-40s and Spitfire Vs swarming like bees around a hive over the Luftwaffe home bases and the outcome would have been the same.

 

[KrazyKraut]

It is interesting that you consider the Ta-152 as being ready when it first began combat operations only months after the first flight of the prototype in August of '44, which crashed along with other prototypes (of course this is what you consider a non-rushed development cycle) while you make an unsupported comment that the P-72, whose prototype was flown in Feb. '44 and in production, would not have been ready if needed. Oh, I forgot, it is not German.
Considering the fact that the P-72 was basically a re-engined P-47 and the Ta-152 had a highly modified fuselage, new wing, and a new engine, I suspect the P-72 prototypes were more ready than the Ta-152 was when it first entered combat.

Please, YP-80 prototypes crashed too killing at least two test pilots as did the XP-72 prototype when the Jernstadt blew the supercharger (to be fair it crash landed). Prototypes crash, rushed development or not. And the airframe of the -72 was also significantly redesigned. Btw, your evaluation that the XP-72 was more combat ready than the Ta is based on what exactly? That it's American?
Fact is it never entered production, other contemporary US design evolutions did. There simply was no more use for a piston interceptor. Even if the war had continued into 1946 for whatever reason, the next US interceptor would've been the P-80 and not the XP-72.

Me-262-outstanding aircraft and would have been competitive for several years.
He-162-marginal performance for a jet. Not much advantage except for producibility.Not much faster than the Meteor, P-80 being much superior. It probably would have killed more inexperienced German pilots than allied pilots.

He-162 had in many ways superior performance to the Me-262 so how exactly was its performance marginal? Its only problem was a rather limited range, which was a design choice because it was of little concern at that time. Structural integrity problems had already been largely solved apart from a still too fragile rudder, but yes it was more of a plane for experienced pilots. But then it most likely was the cheapest of all the 1st generation jets. And where exactly was the P-80 so "much superior"? Speed? Climb? Maneuverability? Critical Mach? Accident rate? Costs?

Again, from plans to combat is often a rocky road. Based on Tank effort in Argentina, this design was several years away from combat capability. In fact it seems that the Mikoyan design team was more capable of solving the problems of this design than was the Tank team.

They also had a shitload more budget behind them. The MiG-15 is also not more of a copy of the Ta-183 than the Bearcat is of the Fw-190: They copy design principles but the actual outcome is very different. The Pulqui IIs development was troubled, no doubt, but I love how you immediatly imply this to be due to a lack of capability on the German designer's part.

 

[kool kitty89]

The He 162's range was nearly as good as the Me 262's at just over 600 mi (~970 km) cruising at altitude. The disadvantages with the 162 were some structural problems with the oversensitive rudder assembly, which wouldn't have been difficult to fix, and not a problem if the Pilot knows to be careful about it. And the other being lack of rear visibility due to the engine, and smaller armament. (it wouldn't have been best as a bomber killer)


The P.1101 was the closest next gen a/c to becomeing a reality. In flight variable sweep was never to be part of the design, and the adjustable sweep of the prototype was for testing purposes only.


I agree that the Ta 183 wouldn't have been ready in a practical time period, the P.1101 was the way to go. (possibly swept wing varients of the Me 262 and He 162 as well)



The coment on the Ho 229 is flat wrong. Flying wings can be designed to be stable without modern fly by wire systems, Bill has discussed this before. (I believe it was in the last few pages of the "What plane (any side) would you develop further" thread) How do you think the N1M, N9M, or all the other Horten brothers' flying wing projects worked?

According to tests flights of the Ho IX (both the Glider and Powered prototypes) showed good handeling characteristics with only a slight lateral instability.

However the lateral controls (rudder input provided by airbrakes near the wing tips) would have resulted in slow yaw control. (making aiming somewhat difficult) Increasing the size of the airbrake-"rudders" would have helped though.

 

[bada]

OOh an, after so much pages, i hoped to see some aerodynamical sudies, with nice graphs and all that kind of stuff, but instead i see only a pissing contest of who made the best piston operationnal airplane, and in this case, the best operationnal, serial build still is the ta 152
and don't come with some x-planes.... otherwise there are some V-planes also than kicked the behinds!


davparlr
Considering the fact that the P-72 was basically a re-engined P-47 and the Ta-152 had a highly modified fuselage, new wing, and a new engine,

aah? highly modified fuselage??? where??? can you tell me?

the fuselage is a standard Anton fuselage (as are all the 190!) lenghtened as the d9 with simply a bigger tail to compensate the higher torque of the jumo, just like on the A9 version with the 801TS version...
There is nothing highly modified here, Tank took the same recepy as he did for the D9 but readapted the tail for the torque.

New wing? yes! very clean wing

New engine? nope, already in use on the ju88 high alt version.

Now: about the Ta183:

dont compare this plane to the pulqui, those planes have nothing to do with eachother!

The Ta 183 was desingned and windtunnel tested by Mutlhropp and the pulqui was a tank's shot to rebuild the Multhropp desing and to try to make it lighter, that's why the pulqui is a high wing and the ta183 an median wing plane. Muthropp designed a whole centrale structure able to sustain the forces in flight on the wings, tank tried to eliminate this feature caus in his eyes, it was too heavy, so the only solution was to adopt low wing or high wing config. he took the second option and we all know what the results were

KoolKitty:For the flying wing: i will ask you a question:
by what means do you think the BV141 was able to fly??? it's fully asymetric!
it's aerodynamicaly incorrect! but it flew and it flew very well (from accounts). The solution is simple:
they used an automatic aileron, rudder and flaps stabilisator! this very small mecanisme could have been installed on the Ho229, but the horten brothers weren't aware of that system, because they were ....will not say that here, much too vulgair.
This mecanisme was build by Patin but don't remember right now the number of that stuff, have to do some search.
This patin stuff compensated constantly all the slip and roll than could occur on the bv141, the pilot didn't even noticed it when it was working.

Now: i hope to see some nice charts here soon!

 

[kool kitty89]

He meant it was a new engine for the Fw 190 airframe. (though the 190D had already been using the Jumo 213)


Also I was wrong about the N1M, it had some stability problems. (as did the Ho I)


And while the Patin stabilization system certainly would have helped, the Horten brothers had already found a sucessful aproach for stability.

Bell-shaped lift distribution!



I agree that this thread is getting way off topic, I'd like to see it get back on too.


Soren can you post some of those Fw 190/Ta 152 data tables? (the ones with the A-8, A-9, D-9, D-13, 152 H, etc)



And Bill do you remember which thread we had that discussion on the stability of flying wings recently. (it wasn't the further development one...)

 

[kool kitty89]

Ok, it wasn't Bill, and it wasn't about the Ho 229 either. It was about the viability of large flying wings on the "players in a prolonged war" thread.

The YB-49 could not make the trip one way with weapons. It had a ferry range of 3575 miles.



I am not sure this is correct. According to the book "Northrop, an Aeronautical History" (published by Northrop), "Early YB-49 flight testing turned up inadequate rates of yaw oscillation damping, a condition that is vital for a stable bombing platform. As a corrective action, a Minneapolis Honeywell Electronic Yaw Stabilization System, or "Little Herbert" was installed. This bombing autopilot made the YB-49 into a very stable platform."

According to the book, the exact cause of the crash of the YB-49 is not known. It is believed that "excessive positive acceleration as would occur in a severe gust, pull up, or pitch-up" caused the wing to fail. The aircraft was very clean and would accelerate rapidly (as would the B-2, which I have flown in the simulator) and over-speed followed by a pull-out could have been a factor. It also said that that wind tunnel test demonstrated that the wing would not tumble.

The wing had much potential as shown by the fact that the B-2 is almost the same size as the YB-49. Its cancellation is questionable and a couple of things stand out, first, why were all the aircraft scrapped (a travesty and it crushed John Northrop and ruined his health), and, the Secretary of the Air Force (Stuart Symington) joined Consolidated when he left government. The book mentioned none of this.

 

[Soren]

Claidemore,

No Ta-152 was shot down, and Aufhammer's a/c wasn't hit either, you just presume it was based on some after action report mentioning 109's.

Fact is that Sattler crashed without any enemy action, and later on after the dogfight Reschke Aufhammer both went back in formation, and neither Aufhammer or Reschke mention anything about his a/c being shot down.

Reshke claims that Herman Stahl and his Ta152 were lost in a combat with Yak 9s on April 24/45.

And where the heck did you get that from ??

 

[Soren]

I have to agree with the others here. Just because no one saw him get shot down, does not mean he was not shot down. Soren, in the heat of combat you dont allways see everything.

In the heat of combat ?? Adler Sattler dived crashed whilst all three were flying in formation toward the target area, there was no combat of any sort, which is the point I've been trying to stress for some time now.

However Claidemore seems to believe that Reschke and his wingman, despite seeing Sattler start to dive out of formation and then crash without responding, somehow missed Sattler's a/c being shot at and hit. My question to this is how the heck do you your first wingman miss seeing your second wingman getting shot down whilst flying in formation with you when you both noticed him from the moment he started to dive and then crash ????

 

[Soren]

KK Bada, good posts both of you.

I'll address them later today or tommorrow.

 

[kool kitty89]

Soren, Bill's post made some good points on what could have happened:

For that type 'unexplained' loss of control there are usually three root causes - natural and very sudden death (unlikely but possible), stray rifle bullet or projectile killing the pilot instantly, or a mechanical failure like oxygen causing unconsciousness (no radio warning of trouble) - also unlikely particularly at low altitude.

Any other explanations?

And not to draw the side arguments out any further, but I think the biggest limiting factor of the P-72 would have been the engine, inless P&W realy put pressure on getting it into production fast, I dont think too many would have been available. (certainly not in the numbers the R-2800 was being turned out in)

And there were also maintenence difficulties with that engine throught its service life. (not so much reliability, or even the oil leaks -common to all very large radials- but some odd characteristics with operation)

As said before, I think the P-47J was the better choice. (range was already good enough for escort duties- even with the 305 US gal of the early P-47's and fuel efficiency was better than other P-47's-, but encorporating the P-47N's wing -or adding the P-47J's nose to the P-47J- would have been even better, and with improved maneuverability, speed would drop but probably still nealy 490 mph at 32,000 ft) Also note that at 2,100 hp military power the XP-47J managed 470 mph.

 

[Soren]

Didn't see Bill's post, but yes all are possible under certain circumstances, and personally I believe the first one based on Reschke's description of what happened.

 

[Kurfürst]

Not by any propeller driven aircraft. To beat that 480 mph airspeed at SL, any prop plane you named would have had to have one heck of a new engine, sporting probably a 50% increase in power.

480 mph at SL with a 3000 HP engine in a 6+ ton aircraft?

Wikipedia nonsense. The purpose-built, tiny Heinkel and Messerschmitt racers did something like 465 mph near SL with a 2900 HP engine...

Much more realistic specs are for the XP-47 were 490 mph at 25,000 feet, with a 3450 HP engine. Its good, but aint that hot allowing for production tolerances, operational equipment, and it certainly would take some time to clear 3450 HP for operational use for the R 2800.

Republic XP-72

Probably similiar as the P-51H case, the intial company calculations were rather impressive, the actual performance of the aircraft with operational equipment, from flight tests was rather closer to the P-51D than the projected specs.

 

[kool kitty89]

Kfurst the XP-72 used the massive 28 cylinder, 4 row, 71.49L "corn cob" R-4360 "Wasp Major" radial engine of 3450 hp. Late models produced 4,300 hp.
It weighed a good 1500 lbs heavier than the R-2800. (although less than 3 in larger in diameter)

It was basicly a further development of the XP-47J concept, up-engined and strengthened airframe.

The XP-47J itsself used the same 2,800 hp R-2800-57C engine as the P-47M/N, and actually acheived 507 mph in testing at 32,000 ft. With 470 mph at 2,100 hp millitary power, and 435 mph at 1,700 hp max continuous.



I agree that the 480 mph SL figure seems wrong.

 

[KrazyKraut]

The He 162's range was nearly as good as the Me 262's at just over 600 mi (~970 km) cruising at altitude. The disadvantages with the 162 were some structural problems with the oversensitive rudder assembly, which wouldn't have been difficult to fix, and not a problem if the Pilot knows to be careful about it. And the other being lack of rear visibility due to the engine, and smaller armament. (it wouldn't have been best as a bomber killer)

I have seen figures ranging from ~600 km to 970 km plus one source indicating flight endurance was only around 30 minutes (probably the last one simply quoted the Volksjaeger requirements though). Is there a good book about the Sparrow?

 

[davparlr]

Please, YP-80 prototypes crashed too killing at least two test pilots as did the XP-72 prototype when the Jernstadt blew the supercharger (to be fair it crash landed). This has nothing to do with rushed development. And the airframe of the -72 was also significantly redesigned. And your evaluation that the XP-72 was more combat ready than the Ta is based on what exactly? That it's American?

Many prototype aircraft crashed including the P-38, and I don't think that is significant, however, if you look at the Ta-152 development, we see the first prototype, Fw-190V-33/U1 flew on July 12, '44, crashed July 13, '44. The second prototype, Fw-190V-30/U1 flew August 9, '44, crashed August 13, '44 (13 seems to be a bad number). A third prototype, V-18/U2, crashed October 8, '44. Two prototypes made it through. Now remember the XP-72 flew February 2, '44. I would bet that the XP-72 had more flying hours than all of the prototype Ta-152s when preproduction started on the Ta-152, and possibly before the Ta-152 went operational (wikipedia (??) states only 50 flying hours were complete by end of January, '45). If this is true, then it is not unreasonable to assume that the P-72 had more bugs worked out of it than the Ta-152H-1, and was therefore more "ready". Now, all of this info was taken from a couple of sources and may be in error. If so, I'm sure it will be pointed out.

Fact is it never entered production, other contemporary US design evolutions did.

The P-72 was primarily designed as a interceptor. It was determined that the Allies did not need an interceptor and it already had an advanced escort, if necessary, (P-51H) in development, and the development funds were moving towards jets. Cancellation of the P-72, after production start, was not due to performance (it was excellent) but rather lack of a mission. One source said that the P-72 program was cancelled around VE day. So I guess both the Ta-152 and the P-72 were both cancelled at the same time. Soren said "there was no Allied prop job in development which could match the Ta-152's performance, and with the Jumo 213J it was far superior in every parameter of performance from SL and up", which I think is probably wrong (I don't know, maybe that 213J engine could produce 3000 hp).

There simply was no more use for a piston interceptor. Even if the war had continued into 1946 for whatever reason, the next US interceptor would've been the P-80 and not the XP-72.

That's also true with the Ta-152H.
[

He-162 had in many ways superior performance to the Me-262 so how exactly was its performance marginal? Its only problem was short range, which was a design choice because it was of little concern at that time. Structural integrity problems had already been largely solved apart from a still too fragile rudder, but yes it was more of a plane for experienced pilots.

I will have to defer to your statement about performance, however, my opinion that the aircraft was seriously flawed for its initial design goal, e.g. that poorly trained pilots could fly it, has not changed. In addition, I would not be surprised if it did indeed kill more Germans than enemy. The limited endurance was a game loser for early German jets. The most dangerous time for a German jet was taking off and landing. If the He-163 had a 30 minute endurance, that means it would be exposed to the most dangerous part of the mission twice as long as an aircraft with an hour endurance, i.e. for every hour mission time the He-163 would have to be exposed to take/off landing four times, whereas an aircraft with one hour endurance would be exposed twice. Adding the additional fuel to increase endurance of this thrust limited aircraft would have significantly affected aircraft performance.

They also had a shitload more budget behind them. The MiG-15 is also not more of a copy of the Ta-183 than the Bearcat is of the Fw-190: They copy design principles but the actual outcome is very different. The Pulqui IIs development was troubled, no doubt, but I love how you immediatly imply this to be due to a lack of capability on the German designer's part.

I threw that comment because I knew it stir up comment. Tank was an outstanding aircraft designer/engineer and I am sure he had less monetary support than Mikoyan, but he and his design team did have far more experience and understanding of that particular design which should have mitigated this disadvantage. Mikoyan, no second rate design/engineer himself, was able to build an aircraft very similar to Tank's and to get in operational in a very short time, an impressive feat. Tank and his team struggled with his design getting it ready for operations.

They copy design principles but the actual outcome is very different.

You are right. One of them became one of the worlds great aircraft, the other struggled to work.
The point of it all was that Soren implied that this aircraft was combat ready once a production aircraft was delivered. It wasn't. It was most like two to three years off

 

[renrich]

Kurfurst, I agree. I believe 470 or 80 at SL,TAS with a P72 or whatever is highly speculative. What is the record for a prop plane? I believe it is held by Rare Bear and it is around 470 mph and ,maybe not at SL. Perhaps at 5000 or so feet.

 

[davparlr]

The coment on the Ho 229 is flat wrong. Flying wings can be designed to be stable without modern fly by wire systems, Bill has discussed this before. (I believe it was in the last few pages of the "What plane (any side) would you develop further" thread) How do you think the N1M, N9M, or all the other Horten brothers' flying wing projects worked?

All of Northrop's, who had much more experience in flying wing aircraft than the Horton's, had vertical stabilizers.

According to tests flights of the Ho IX (both the Glider and Powered prototypes) showed good handeling characteristics with only a slight lateral instability.

However the lateral controls (rudder input provided by airbrakes near the wing tips) would have resulted in slow yaw control. (making aiming somewhat difficult) Increasing the size of the airbrake-"rudders" would have helped though.

Actually, I am not sure this is correct. A small amount of drag on a wing tip should input a good amout of yaw rather quickly.

A pure flying wing aircraft can be built with some stability (except in the lateral axis without veritcal stabilizers). Roll stability is normal, however pitch stability is very low and yaw stability goes from okay to close to zero depending on the size of a vertical stabilizer.

None of the aircraft you mentioned went through the intensive flight test required of a fighter. Normal stalls, high g stalls, cross controlling, high roll rates, abrupt pitch inputs, high angle of attack flight, high speed dive recovery, negative g operation, weapons operation, more.

I believe these test would have revealled certain characteristics of a flying wing that would require extensive patchwork redesign, for certain a vertical stabilizer on the the Ho 229. Making a flying wing into a fighter is a whole different problem than making one for a bomber or glider for for just flying around in lazy circles.

 

[davparlr]

OOh an, after so much pages, i hoped to see some aerodynamical sudies, with nice graphs and all that kind of stuff, but instead i see only a pissing contest of who made the best piston operationnal airplane, and in this case, the best operationnal, serial build still is the ta 152

I have shown data, post 231, that shows the P-51H clearly superior to Ta-152H below 25,000 ft. It was said that if the P-72 did come it would outclassed by an upgraded Ta-152. So, if you want me to present data on the P-72, provide the data for the upgraded Ta-152 and the other "V" planes.

davparlr
Considering the fact that the P-72 was basically a re-engined P-47 and the Ta-152 had a highly modified fuselage, new wing, and a new engine,

aah? highly modified fuselage??? where??? can you tell me?

the fuselage is a standard Anton fuselage (as are all the 190!) lenghtened as the d9 with simply a bigger tail to compensate the higher torque of the jumo, just like on the A9 version with the 801TS version...
There is nothing highly modified here, Tank took the same recepy as he did for the D9 but readapted the tail for the torque.

Okay, I will say that the Ta-152 fuselage was not modified much more than the P-72. It was longer than the D-9 and considerably heavier.

New wing? yes! very clean wing

Even a "clean" new wing is significant.

New engine? nope, already in use on the ju88 high alt version.

Now: about the Ta183:

Not the 213E with GM50 and nitro.

dont compare this plane to the pulqui, those planes have nothing to do with eachother!

The Ta 183 was desingned and windtunnel tested by Mutlhropp and the pulqui was a tank's shot to rebuild the Multhropp desing and to try to make it lighter, that's why the pulqui is a high wing and the ta183 an median wing plane. Muthropp designed a whole centrale structure able to sustain the forces in flight on the wings, tank tried to eliminate this feature caus in his eyes, it was too heavy, so the only solution was to adopt low wing or high wing config. he took the second option and we all know what the results were

So, your saying that Tank wasn't that good, huh. Didn't the Ta-183 have a Ta in the front and not Mu?

Now: i hope to see some nice charts here soon!

Actually, I think it is your turn, provide me with the charts on the Ta-152H with the 213J engine.

 

[davparlr]

480 mph at SL with a 3000 HP engine in a 6+ ton aircraft?

Wikipedia nonsense. The purpose-built, tiny Heinkel and Messerschmitt racers did something like 465 mph near SL with a 2900 HP engine...

Much more realistic specs are for the XP-47 were 490 mph at 25,000 feet, with a 3450 HP engine. Its good, but aint that hot allowing for production tolerances, operational equipment, and it certainly would take some time to clear 3450 HP for operational use for the R 2800.


Probably similiar as the P-51H case, the intial company calculations were rather impressive, the actual performance of the aircraft with operational equipment, from flight tests was rather closer to the P-51D than the projected specs.

I agree that the 480 mph SL figure seems wrong.

Kurfurst, I agree. I believe 470 or 80 at SL,TAS with a P72 or whatever is highly speculative. What is the record for a prop plane? I believe it is held by Rare Bear and it is around 470 mph and ,maybe not at SL. Perhaps at 5000 or so feet.

I only found one reference, non-wikipedia, to the XP-72 actually being timed at 3200 ft at 480 mph. I didn't really think too much about it. On review, we can apply some thumbnail aerodynamics to see if this is reasonable. We have data that shows the Tempest II, a similar radial engined aircraft weighing 8,917 lbs empty, with 2520 hp, as capable of doing 416 mph at SL and 425 mph at 5000 ft, which is about 420 mph at 3200 ft. Now, knowing that drag is the square of the speed, we can calculate the hp required for the Tempest II to obtain 480 mph at this altitude. The increase of speed from 420 to 480, (480/420) is 1.14. Squaring this we get 1.3. Multiplying this by 2520 hp, we get 3291 hp. The P-72, weighing 11,470 empty, has 3,450 hp. So adding in the extra weight, the 480 mph at 3200 ft is aerodynamically reasonable from a thumbnail look.


Renrich, Rare Bear, weighing 8500 lbs, set a worlds speed record of 528.3 mph with 4000+ hp. For the Tempest to achieve this speed using the above calculations, is 3983 hp, so calculations also appear reasonable.

So, I think we have no reason to believe the speed of 480 mph for the XP-72 at 3200 ft is outlandish.

 

[thrawn]

davparlr,

i find it highly doubtful, that the xp72 can manage 480mph at SL too.
I also think it is questionable that the Tempest II runs 416mph at SL. May I ask where you get this from?

In comparison, the Fw190A-9, a smaller and lighter fighter than the Tempest II, is capable of ca. 370 mph with 2250 hp at SL (if my memory is right), so i dont think that the Tempest with 300 hp more can go so fast, especially if you consider that the jump from 2000 hp to 2250 hp results in an speed increase of only 15 mph at the A9.

I think your calc is maybe wrong. Drag is square of speed and so is the required Thrust. Power is Thrust*speed, so Power must increase cubic with speed.

greetings

thrawn