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

[davparlr]

Dav, I don't believe that RB was at sea level though. I don't believe the Tempest could manage 416 mph at SL. My book shows the fastest US WW2 fighter at SL was the F4U4 at 380 mph. I know there are numbers floating about which show various other AC as faster than that but I don't believe those numbers are accurate or they are not for standard production airplanes. Same book shows P47M at about 370 mph at SL.

After some research, all I could find was that Las Vegas was selected because of its high altitude. So, I suspect that the record was made at low altitude (otherwise it would matter what the base altitude was). Since Vegas is about 2200 ft pressure altitude, the record was probably run below 5000 ft. (3000 may be reasonable).

I am a big fan of the book you recommended, America's Hundred Thousand, but, although good (I have used it quite a bit), I do not think it is the best reference for perfomance. Performance by model is limited (by necessity) and descriminate between fuel (P-51B performance is significantly improved with high octane gas) is non existant. My favorite source is fligh test data, which spitfireperfomance has a great library, or manufactures data (estimating error has to be considered here). Now, I wil tell you that data on the F4U-4 drives me crazy. I have looked at your book, flight test data, and Navy data, and it all looks like they are testing different aircraft! For instance, rate of climb at SL goes from 3600 ft/min from your book to 4800 ft/min from the Navy document. All at combat power!

480 mph at SL for the XP-72 is high. My calculations were wrong. It is more like 450-460 mph. as an estimate.

 

[davparlr]

maybe if you want to talk about prototypes, we can start about the Do-335,

I am not sure you would really want to do this with the P-72, since it is about 5000 lbs heavier and only 150 hp more. Ceiling P-72-42,000, Do-37,400, range P-72-1200 miles, Do-870 miles.

that needed to shut down an engine to be able to sustain the cruise speed of the p51d whan it was brought back to england

I doubt very seriously that the Do-335 could maintain alitude at idle on both engines much less maintain 325 mph true.

funny for a 10tons plane to have the same cruise speed on one engine as the half weight mono-engine fighter, don't you think?

Yes, I had a big laugh.

don't get it

A wing change has a significant impact on an aircraft. There are changes in stall behavior, roll rate, climb rate and angle, airflow across the aircraft, stability, airspeed under various load factors and aoa, trim response, etc. All of these have to be evaluated and documented in flight test.

at the end of 44 Tank wasn't a desinger anymore, it was the General director of the Fw company!
he wasn't envolved in the engeenering of the new edged projects. and the Ta prefix was simply given by the RLM as gift to Tank for it's work for the LW. Nothing else, multhropp was a young engineer, with modern ideas.(he worked for the us after the war )
If you invent something for the company you're working for, will the final product or the prototype of this product have your name or the name of your company?

Interesting information.

the ta 152 never has this engine , so where could i find those charts?
Just like the p72 never flew operationnaly and was never tested as it, so why bother?

Good. I don't have to find the charts for the P-72, if they exist.

Please, stop the pissing contest and let's focus on the 3 planes we can obtain real data for: p51D22/25,109G/K and the 190 (any version) and let's forget about the small series or the x-planes.ok?

It's okay with me, but keep the comparisons to actual aircraft, not with possible changes.

Also, as I state before, this whole site is biased in that it compares aircraft that had no significance in the war. In reality, the critical battles of the war included the P-51B/D, Bf-109 G, and Fw-190A-6.

and about the A9:

I was just making comment, not arguing anything, I could care less. You could have just said my source was wrong.

 

[kool kitty89]

davparlr, I think Bada was just saying the new wing was clean as a positive comment, not claiming that a new clean wing wouldn't change the a/c. (also note that it had boosted ailerons to improve roll)



And on the 3-blade prop, it seems I was wrong about it being standard (I hadn't read the P-72 article in a while) and also wrong about the problems of that particular prop. This propeller didn't seem to suffer from any significant problems except it seems it was not very available at the time. (not in production yet?) The only other prototype to use it iirc was the YP-60, and that had its own isues.

 

[renrich]

Dav, I know what you mean about some performance data driving you crazy on F4U4. I even see some inconsistencies in the evaluations of the fighters in the joint fighter conference in 1944. I do believe that Dean's book is fairly conservative but probably reflects the performance of the standard production airplane in the field. The other book I use, "The Great Book of WW2 Airplanes" agrees almost exactly with Dean on US fighters and the performance figures. Soren, regarding your statement about the Germans being ahead in all the technical fields, they were indeed very advanced in many areas but let us not forget that the British muddled about and were ahead in radar and stayed ahead, also asdic or sonar was good for them. As far as piston engined fighters, the British fighters were overall the equal of the Germans and their bombers as well as the American's were much superior. Remember that the US had to design aircraft for a different mission than Germany and Britain. Neither Germany or Britain had competent shipboard aircraft. The US and Japan excelled at that. There are many other examples in that area. I would not say they were ahead in math or physics as the atomic bomb came to life in the US.

 

[davparlr]

And afterall: 3 out of 5 is SO much worse than 1 out of 2, right? That's a whole 17%.

Actually, statistically, 3 out of 5 is much more significant that one out of two. Check it out in a good statistics book.

 

[pbfoot]

Because wherever the XP-72 is discussed, it is said that the Aeroproducts propeller was the intended one since torque was too extreme with the standard 4-blade. Since the crash did not seem directly related to the propeller (rather the pilot being seemingly a bit over ambitious) I see no reason not to order the safer design into production, since as mentioned that was the major (only?) difference.

For a kind of similar case the YP-80A was called into production before the respective prototype even flew.

davparir has actual experiance with aircraft I'm kinda curious about your background as to be so sure about your statements

 

[kool kitty89]

He wasn't arguing with Dav there, that was pertaining to my statement, which I admitted was wrong.

THe 4-blade prop was only used on the 1st prototype as an intrim measure as the 6-blade contra-rotating prop wasn't available. (I don't know why it wasn't later refitted with a new prop though, only the 2nd one got it)

I was going off memory, and needed to re-read the article.

 

[KrazyKraut]

double post; see below

 

[KrazyKraut]

Actually, statistically, 3 out of 5 is much more significant that one out of two. Check it out in a good statistics book.

So, which statistical test would you suggest to prove your hypothesis? My first guess is any statistical test will fail because the sample sizes are much too small (2 and 5). Feel free to correct me, it's been a while since I've done this:

Tests for group difference:
Approximative two group Gauss-test: Not applicable since sample sizes are smaller than 30 (5 and 2 respectively).

Two group t-test: Only applicable if sample size or variances are equal in both distributions. Since we already know that sample sizes aren't we will check for equal variances with an F-Test.

Two group F-Test:

1=crash 0=no crash

XP-72:
sample mean mu(xp)=0.5
sample standard deviation s'(XP)=0.71

Ta-152 H:
sample mean mu(ta)=0.67
sample standard deviation s'(ta)=0.55

Nullhypothesis: s(xp)=s(ta)

F-Test statistic: v = s'(xp)^2 / s'(ta)^2

v=0.5/0.3=1.67

critical values for F-distribution F(1;4)=7.71

v<Fcrit, we cannot reject the Nullhypothesis of variances being equal;



Now the two group t-test:
Nullhypothesis: mu(xp)>or=mu(ta);

H1: mu(xp)<mu(ta) i.e. mean crash rate of XP-72 s is smaller than that of Ta-152 H at significance level alpha=0.05

and now it's getting ugly

t= [mu(xp)-mu(ta)] / sqrt{[(2-1)*0.71^2+(5-1)*0.55^2]/(2+5-2)] * [(2+5)/2*5]}

t=-0.71
tcrit(5;0.96) (left-tail) = -2.015

t>tcrit

H0 cannot be rejected; mean crash rate of XP-72 is not significantly smaller than that of Ta-152 H

Feel free to correct me on any mistakes.

 

[davparlr]

. Feel free to correct me, it's been a while since I've done this:

There is no way I will correct you as it has probably been a longer while since I have done this.

Actually, I was addressing the confidence level of the two tests. I believe that if five aircraft are tested and compared to two, the confidence of the first test being more accurate than the second is significant. Say another Ta-152 is tested and flies well. Now, six Ta-152s were tested and three failed. Two P-72s were tested and one failed. Now the failure rate of both aircraft is the same, 50%. However, the confidence that the failure rate of the Ta-152 is 50% is much higher than the confidence of the failure rate of the P-71 being 50%. So, when I said that 3 out of 5, is more significant than 1 out of 2, it is probably like plus or minus 30% for the Ta-152 to plus or minus 55% for the P-72, depending on the confidence level. This is intuitive in that a sample of 100 for 100 aircraft would yield 100% accuracy. The sample size is very small.

In reality, this is oversimplifying everything. We have no reasons for loss of the Ta-152s, it could be everything from massive structural failure to a "stroke". Sampling is not random, etc, etc. There is no doubt that, with three failed prototypes, and 50 hours of flying time (if this is true), the Ta pre-production program, and maybe production program (at least to enter combat) was a high risk program (such as was the P-80). I think that high risk programs were standard operation procedures for WWII. It is obvious the Germans evaluated and weighed the risk as acceptable.

 

[Blue Yonder]

I believe the P-51D Mustang would be the best bet.
The 109 had few crashes on landings and takeoffs, landings more often then takeoffs, due to the landing gear being small and narrow. But the 109 was similar to the Spit in this aspect. I have spoken with several pilots on this topic (the alleged landing and takeoff crashes statistics) that flew during the war along with sifting through several archives and was unsuccessful in locating any statistics verifying this.

 

[Soren]

Davparlr,

The Ta-152 wasn't in any way a high risk program, the development had been underway for some time and the a/c had been thuroughly tested as well. Furthermore the problem plagueing Ta-152 was never structural but always related to the engine and its supercharger gears. The structural design was perfect and very rugged, and like all who flew the bird mention it was a dream to fly, absolutely fantastic.


Read "Focke Wulf Ta 152 High Altitude Fighter" by Dietmar Hermann.

 

[kool kitty89]

We've been through the take-off/landing issues with the 109 before. It was a nuisance, but not a serious problem. (and very few a/c were actually lost -damaged to unreparable extent- due to such accedents)

 

[Kurfürst]

The Ta-152 wasn't in any way a high risk program, the development had been underway for some time and the a/c had been thuroughly tested as well. Furthermore the problem plagueing Ta-152 was never structural but always related to the engine and its supercharger gears. The structural design was perfect and very rugged, and like all who flew the bird mention it was a dream to fly, absolutely fantastic.

... and, in any case, there was the Bf 109K-14 programme as backup for a very high altitude bomber interceptor, should it have been really needed.

But, they were the cure for a disease never materialized (über-high flying über-fast B29s - as told by Japanese pilot rumors) it turned out.

 

[Soren]

The Ta-152 wasn't designed to counter the B-29, it was designed purely as an airsuperiority fighter. Nothing was known of the B-29 when the Ta-152 was designed.

 

[Kurfürst]

... then why the extreme high altitude engine, the extreme wingspan..? GM-1..?

If you read RLM discussions, from mid-1943 onwards, there is profound interest in extreme high altitude engines and interceptors... DB 628 for example (a two-stage, four-speed DB 605A basically).

 

[Soren]

Because the LW wished an a/c with complete aerial superiority at all altitudes over any Allied fighter, and a high ceiling is a crucial factor to achieving this. Furthermore the B-29 wouldn't be flying any higher than the German fighters already in service by mid 44 were capable of, and therefore designing a new a/c specifically to counter the B-29 was pointless since the a/c in service already were more than capable of dealing with the B-29 if it ever came.

However the P-47 P-51 both featured better high alt performance than most German fighters in mid 1944, which was a problem. German fighters were usually superior to Allied fighters from SL and up to 25,000 ft, but the bombers usually flew above that altitude. The Ta-152H would eliminate this problem and would enable pilots to stay WAY above any Allied escorts and attack the bomber streams at will, the Ta-152H having a 2.5 to 3 km higher service ceiling than any Allied fighter in service. And with its far superior maneuverability, speed climb rate nothing could match the Ta-152H in a dogfight.

You should read Dietmarr's book, it's worth every penny and filled with original documents. It also explains the often reoccuring urban myth of the Ta-152 being designed to counter the B-29.. it wasn't, it was designed purely as an airsuperiority fighter capable of taking on any Allied fighter and always win.

 

[Soren]

Also the Jumo 213E wasn't really an extreme high altitude engine, but the GM-1 system made it a great performer at high altitudes. However the high service ceiling of the Ta-152H can be attributed more to its wing, which is mostly what allowed it to go that high (15.1 km).

 

[Kruska]

Hello Soren,

I don't know Soren. By the time the USAAF would have send the B-29's to Germany (Thank God it never happened) it would have maybe been around August/September 45. Let's forget the A-Bomb – even though it was designed/meant for Hitler Germany – these Ta-152 which would not have been around in any significant numbers before September 45 would have had to face F-80's and British Vampires as B-29 escort planes rather than just US props.

Regards
Kruska

 

[kool kitty89]

F-80's couldn't make the range to pennetrate deep into germany and still have enoughfuel to fight for any meaninful amount of time before turning back. (that's if they had the larger 230 US gal tip-tanks, with 165 gal, much less, with the 265 gal tanks also later used on the F-80 it might have made it. If it could have been modified to carry the 300 gal P-38 tanks it should have had the pennetration range -however, it would have required strengthening the wing, as the 265 gal tanks were already threatening to overstress the tips-)

That's if operating from England. From mainland Europe it's another story.


And the P-80 is the only allied jet with near the range required for escort.

Vampire Mk.I and (particularly) the Meteor are out.