P-47: We could easily out-turn the Jerry

[hogenbor]

A few days ago I encountered a Ta-152H in a P-51B at about 25k. To my amazement I had no trouble at all overtaking him and when I got on his tail he could not shake me off no matter what he did. Easy kill if there ever was one.

[MiloMorai]

One can not only look at the wing loading, the 'power to weight' also has to be considered.

Also, to be considered is the weight of the a/c when in combat. The P-47 had burned off ~1000lb of fuel by that time.

From the Russian graphs, it can be seen that Allied fighters, even the P-47D-25, were much faster than the K-4 above 8-9km.

[bozon]

Originally posted by Kurfürst
... the thunderbolt had extremely high wingloading, making it unlikely to be as goodwilled as a spit when manouvering well above the clouds.
 

True that the jug had a high wingloading, but not as high as some people think. One must remember that the jug is a flying tanker with 370 gallons of internal fuel (3 times the 109 fuel load). The N model had even more internal fuel in the wings.

This means that the fuel load you use for calculating the wingloading is critical. A fuel empty jug has a better wingloading than a 190A8 if I remember correctly. For actual battle condition the result is somewhere in between since you are neither empty nor full. It's the same with all planes, but if you have a beer can sized fuel tank like a 109, it's less of an issue.

I belive this is the case with some P38 figures as well.

Bozon

[rabbidrabbit]

Originally posted by StarOfAfrica2
Lag roll is useful in any plane like that, i.e. one that doesnt turn as well as their opponent.  FW's use it alot also.  Say you are in a Jug or a FW and chasing a spit.  He goes into a hard flat turn to the left.  Instead of trying to follow him, you roll to the right and when you come around 270 degrees in your roll you pull out facing the spit (hopefully) at about 90 degrees from where he started his turn.  It requires a plane with a good roll rate, proper timing, and not overdoing the g-forces in the roll or you'll spin out.  The nice thing is, if you screw up the timing the spit is still committed to the turn and you can zoom out of the fight and get separation.  It will take him a bit to get around where he can chase you and by then you are out of range.  Get some space, get some alt, and try again.

Care to describe that better?  I must be missing something.

[Kurfürst]

Originally posted by MiloMorai
One can not only look at the wing loading, the 'power to weight' also has to be considered.

[/B]

This is very unlikely to favour the P-47, the heavies s-e fighter of ww2...

From the Russian graphs, it can be seen that Allied fighters, even the P-47D-25, were much faster than the K-4 above 8-9km. [/B]

The only allied fighter that was faster above 8km than the K-4 to my knowladge was the Spit XIV. All the rest were slower, some even as fast, particularly the P-47D and P-51D, neither of which can even hit the top speed of the K-4. You are welcome to show some data - the K-4`s top speed was 705 kph/8km, 595 kph/9km, 681kph/10km, 660 kph at 11km. The data I have seen show the P-47D slower than this.

One thing to consider about these altitudes that neither of these fighters had pressurized cocpits, making flights at this heights very tiresome - and rare.

[MiloMorai]

Originally posted by Kurfürst
The only allied fighter that was faster above 8km than the K-4 to my knowladge was the Spit XIV. All the rest were slower, some even as fast, particularly the P-47D and P-51D, neither of which can even hit the top speed of the K-4. You are welcome to show some data - the K-4`s top speed was 705 kph/8km, 595 kph/9km, 681kph/10km, 660 kph at 11km. The data I have seen show the P-47D slower than this.

One thing to consider about these altitudes that neither of these fighters had pressurized cocpits, making flights at this heights very tiresome - and rare.

Why don't you post the Russian graphs you are so fond of. There is one with the K-4, Spit and P-51.

from data supplied in this thread

P-47
690 km/h @ 09.2 km

K-4
595 kph/9km

The Russian graph shows ~690kph@ 8km, ~675kph @ 9km and ~660kph @ 10km, so it its understandable why don't care to post it.

Flying at such heights was not rare for American pilots - read some combat reports.

Then there is statements by 109 pilots that flying at such heights was like walking a tightrope.

[gwshaw]

Originally posted by Kurfürst


This is very unlikely to favour the P-47, the heavies s-e fighter of ww2...

[/i]

This is against my better judgement, but here goes.

Combat weight about 50-60% higher than a Fw 190A, say 8500 lbs vs 13000 lbs. Wing area about 53% greater than a Fw 190A. Not a whole lot to pick and choose between them.

Power loading, the Fw 190A has a large advantage in low gear up to about 1km at 1.42 ata, even over a D-25+ with 2535 hp available. Although at the 72 in Hg figure of 2875 hp or so the P-47D is nearly equal to the Fw 190A @ 1.65 ata. As soon as the Fw 190A has to shift into high gear the P-47D is about equal at 60 in Hg 2300 hp and better at 64 in Hg 2535 hp.

Above about 1 km the P-47 has a power loading advantage, and at bomber escort altitudes it has a huge advantage in PsubS.

The only allied fighter that was faster above 8km than the K-4 to my knowladge was the Spit XIV. All the rest were slower, some even as fast, particularly the P-47D and P-51D, neither of which can even hit the top speed of the K-4. You are welcome to show some data - the K-4`s top speed was 705 kph/8km, 595 kph/9km, 681kph/10km, 660 kph at 11km. The data I have seen show the P-47D slower than this.

One thing to consider about these altitudes that neither of these fighters had pressurized cocpits, making flights at this heights very tiresome - and rare. [/i]

In 1944 testing of the P-47N prototype a P-47D-35 (IIRC) clocked in at 450 mph @ approx 30,000 ft. Which fits right in line with calculated figures for a D-25+ w/o wing pylons.

As for P-51 figures, here is a cut and paste of some P-51 testing:

U.S. Navy Patuxent River Comparison Tests V1650-3 engine at 67" MAP/3000R
Test Weight 9423#
Max Speed   450 mph @ 29200'
       426 mph @ 12600'

Eglin Field tests    V1650-3, 67"/3000RPM
Test Weight 9640#
Max Speed   435 mph @ 27000'
       420 mph @ 13100'
(with wing pylons attached)

Wright Field EE 393 tests      V1650-3 67"/3000RPM
Test Weight 9200#
Max Speed   450 mph @ 28200'
      420 mph @ 15300'

So, with wing pylons attached the -3 engined was definitely a bit faster above 8km then the K-4. And without pylons both -3 and -7 engined models could manage 450 mph or so, about the same peak speed as the K-4, but about 10 kft higher. Leaving aside the question of whether or not the K-4 ever had the fuel to make those figures.

Greg Shaw

[HoHun]

Hi Hogenbor,

>A few days ago I encountered a Ta-152H in a P-51B at about 25k. To my amazement I had no trouble at all overtaking him and when I got on his tail he could not shake me off no matter what he did.

It's certainly true that the P-51B makes a great high-altitude fighter :-)

But with MW50 injection, the Ta 152H-0 should actually outrun the P-51B above 7 km. If it doesn't, I'd suspect it lacks this injection.

The Ta 152H-1 with MW50 injection would outpace the P-51B by about 20 - 30 km/h above 6 km. At 11.5 km, the Ta 152H-1 can also use GM-1, which gives ridiculously good performance.

Still, considering that the P-51B is 1943's standard fighter which uses a normally-boosted Merlin while the Ta 152H-1 is 1945's specialized high-altitude aircraft with two types of special injection, I'd say the P-51B gives a very good account of itself :-)

Regards,

Henning (HoHun)

[HoHun]

Hi Greg,

>Combat weight about 50-60% higher than a Fw 190A, say 8500 lbs vs 13000 lbs. Wing area about 53% greater than a Fw 190A. Not a whole lot to pick and choose between them.

I'd say it's close enough that wing loading alone will not allow any realiable conclusion :-) Do you have any idea of what the Clmax of the P-47 wing might have been? That might allow more accurate estimates.

(I agree that the better power loading up high would obviously have favoured the P-47D over the Fw 190A.)

>In 1944 testing of the P-47N prototype a P-47D-35 (IIRC) clocked in at 450 mph @ approx 30,000 ft.

Hm, that was with a R-2800 "C" engine, but the old D-type wings? Do you know the weight of the prototype? That looks like another useful data point :-)

>As for P-51 figures, here is a cut and paste of some P-51 testing:

>Max Speed   450 mph @ 29200'

That's the one I'm using in my above comparisons :-)

>So, with wing pylons attached the -3 engined was definitely a bit faster above 8km then the K-4. And without pylons both -3 and -7 engined models could manage 450 mph or so

Agreed on the -3, but in my opinion the -7 would be a bit slower in terms of absolute speed due to its lower full throttle height. (I'd say the Patuxent River data shows the speed dropping off unrealistically quickly for the -3 engined P-51, by the way.)

That the -7 engine was preferred over the -3 still is puzzling me!

Regards,

Henning (HoHun)

[StarOfAfrica2]

Originally posted by HoHun
Hi Widewing,

>Listen, there's a wealth of data on the P-47, all of which establish it performance without question.

Do you have a set of data which lists speed, climb and power/critical altitude for one specific aircraft along with the weight? In analyzing P-47 performance, I have only found partial sets so far, which were partially contradictory.

Regards,

Henning (HoHun)

Found this at Rare Aviation while doing a search for another project of mine I'm doing for a friend.  Perhaps it would help?  

http://rareaviation.com/ppandpaieran.html

It says the book is "P47B, P47C, and P47D Airplanes - Erection and maintenance instructions."

They also have pilot's manuals for many WWII aircraft.

[ATA]

P47 creation of a Soviet guy working for another Soviet guy in USA:)
And they say Soviets cant bilt crap:)

[Kurfürst]

Originally posted by MiloMorai
Why don't you post the Russian graphs you are so fond of. There is one with the K-4, Spit and P-51.

[/B]

I am not fond of the Soviet graph on the K-4, as I have better source, detailed and accurate specifications - directly from Messerschmitt.

from data supplied in this thread

P-47 - 690 km/h @ 09.2 km

K-4 - 695 kph/9km

Which proves your earlier statement, "Allied fighters, even the P-47D-25, were much faster than the K-4 above 8-9km." is absolutely incorrect. It was not faster, and esp. not MUCH faster. Looking at those figures, a 6 ton monster w. a turbocharger, and a 3 ton fighter with a simple single staged mechanical supercharger, it is appearant why they found installing huge turbochargers into fighter airframes simply an inefficient method in Germany.  


The Russian graph shows ~690kph@ 8km, ~675kph @ 9km and ~660kph @ 10km, so it its understandable why don't care to post it.

Yes it`s understandable. I put my reliable primary sources above secondary sources, if the former are available.


Flying at such heights was not rare for American pilots - read some combat reports.
Then there is statements by 109 pilots that flying at such heights was like walking a tightrope.

Sure-sure. I can pick as many qoutes of 109s flying at such heights as you wish, including how P-38s gave up to follow old G-6s to such altitudes, but what for. Ceiling of the K-4 was 42 325 ft, this tells it all.

[Kurfürst]

Originally posted by gwshaw
Combat weight about 50-60% higher than a Fw 190A, say 8500 lbs vs 13000 lbs. Wing area about 53% greater than a Fw 190A. Not a whole lot to pick and choose between them.

Power loading, the Fw 190A has a large advantage in low gear up to about 1km at 1.42 ata, even over a D-25+ with 2535 hp available. Although at the 72 in Hg figure of 2875 hp or so the P-47D is nearly equal to the Fw 190A @ 1.65 ata. As soon as the Fw 190A has to shift into high gear the P-47D is about equal at 60 in Hg 2300 hp and better at 64 in Hg 2535 hp.

I didn`t check the numbers, such would be more interesting shown graphically. The turbocharged Jug had constant output up to high altitudes, whereas the FW 190`s dropped off - the BMW 801 was a rather poor performer at high alts, hence the natural division of jobs between 109s and 190s on the Western front.




Above about 1 km the P-47 has a power loading advantage, and at bomber escort altitudes it has a huge advantage in PsubS.

There`s no question about the P-47D being greatly superior to the FW 190A at such altitudes. Not so much compared to the A-9 or D-9, though. Real life testing between P-47d and 190A w/o boost however revealed pronounced superiority of the 190 in manouvers requiring 'hanging on the propellor'.

In 1944 testing of the P-47N prototype a P-47D-35 (IIRC) clocked in at 450 mph @ approx 30,000 ft. Which fits right in line with calculated figures for a D-25+ w/o wing pylons.

The P-47M/N was indeed very fast, very late, and very rare. I though we are talking about the D version, which was in question. Certainly the N was by no means represenative of D performance.


As for P-51 figures, here is a cut and paste of some P-51 testing:

U.S. Navy Patuxent River Comparison Tests V1650-3 engine at 67" MAP/3000R
Test Weight 9423#
Max Speed   450 mph @ 29200' - 724km/h at 8900m.
       426 mph @ 12600'

Yes, results for P-51B with the high altitude engine, without bombracks, which were standard fitting on them for droptanks.. Even at SL, these chopped down 8-12mph, and at such heighst -20mph is rather probable - minimum. IIRC the report even mentions special handling of the surface as well..


Eglin Field tests    V1650-3, 67"/3000RPM
Test Weight 9640#
Max Speed   435 mph @ 27000' - 700kph 8230m
       420 mph @ 13100'
(with wing pylons attached)

Suppose another P-51B/C, lowest drag variant, best altitude engine, now with the standard pylons. A tad bit slower than K-4 at 705kph at the same altitude.


Wright Field EE 393 tests      V1650-3 67"/3000RPM
Test Weight 9200#
Max Speed   450 mph @ 28200'
      420 mph @ 15300'

Again without standard wingracks.


So, with wing pylons attached the -3 engined was definitely a bit faster above 8km then the K-4.

P-51B/-3 w. pylons : 700kph 8230m
K-4 : 705 kph at 8000m
So certainly not.


And without pylons both -3 and -7 engined models could manage 450 mph or so, about the same peak speed as the K-4, but about 10 kft higher. Leaving aside the question of whether or not the K-4 ever had the fuel to make those figures.

Point is they never flown without pylons in USAAF service. Standard fitting, required for long range sorties.

We have already concluded the -3 engines made the sleeker P-51B as good as the K-4, not much difference to speak of.
The V-1650-7 had poorer power output than the -3 at altitude, which would make it slower, plus if we speak of the most common config (draggier P-51D w. V-1650-7, wingracks), it is definieately at speed disadvantage to the K-4 at altitude.

What graphs Neil Stirling posted show the D version to achieve some 663 kph at 10000m - that`s 20 km/h slower than the K-4 at 681 kph at the same altitude, and about as fast as a G-10 or /AS types. Two staged versions of the DB 605 D would rule out the even playing fields for the comparisons, though.

I don`t get your fuel comment. Without fuel either the P-51 was some 700 km/h slower than the 109K and vica versa. Otherwise the type of fuel or the use of MW did not effect the altitude performance above 7000m or so at all, just as 150 grade fuel couldn`t.

All this said, the -3 performances were a bit useless - the bombers flew at much lower altitudes, having poorer superchargers themselves, fuel economy and bombing accuracy also being important. The USAAF realized just as the RAF did that the Merlin 61 and the V-1650-3 offered advantages that are of little use during the typical heights of combat sorties, and switch to the 66/-7, which had less power at altitude, but offered their performance at a much more practical altitude range - up to about 16 000 ft.

If you can provide the graphs, I can put them all in an excell curve vs. altitude, if u r interested.

[MiloMorai]

So, you only use the Russian graphs when it suits your agenda.  Post your more reliable data, if you really have any.

Nice editing job of my post,btw.

it is appearant why they found installing huge turbochargers into fighter airframes simply an inefficient method in Germany.

Sure, then why was a German company developing the Bv155 high altitude fighter late in the war? The Bv155 was originally the Me155, a 1943 design, that was to have a turbo-supercharger connected to its DB engine. Messerschmitt gave up because they could not get past the engineering problems.

I never said that the Germans did not fly at 30kft +.

[Kurfürst]

Why would me or anybody post actual data for you, hmm?