P-63: real performance?

[tomo pauk]

Hello, people,

Following discussion in another thread, I've decided to start a new thread about P-63 performance. Seems like there is a discrepancy between manufacturer claims and actual test results. Also, some charts have projected figures/lines, for future models with future engines.
Here is Jeff's post, maybe we could use it as a starting point:

...
Data for the P-63A-10 came from a graph at Mike's sight. It is titled COMPARATIVE PERFORMANCE OF P-63 AIRPLANES. Its marked CONFIDENTIAL at the bottom and top. Down on the lower left it dated 5 JUNE 1944. Three A/C are listed: P-63A-10, P-63C-1 and P-63E-1. Under the date is the following: HDD,JWA.RHR.FWR.
It appears to be a military graph but by the date I would guess the C-1 and E-1 are calculated. This is around the correct period for the A-10 testing, so who knows.
Actually AHT does give the same roll rate at 275 mph as the NACA graph. Look at the graph on page 410. I think the 100 degrees per second on page 416 is a misprint. The graph in AHT takes a nose dive around 320. I think I'll stick with the NACA until more info is published.
Your right about the "no maneuver position" statement. Right before that it states,"A flap position indicator consisting of a paint stripe along the flap near the leading edge was visible to the pilot." I wonder what that (the statements back to back) is all about?
...

Jeff

...

 

[GregP]

This is one of the reasons why I don't like online charts that don't have the original document number on them ... the conditions of the test / chart aren't apparent.
MUCH better to show the entire document so the test, conditionsm weight, % MAC, etc. are known ... along with the actual aircraft flown. I'll look at the P-63 and get back.

As I recall it made about 422 mph at best altitude (around 22,000 feet or so), climbed MUCH better than the P-51 and rolled better, too ... but I'll go check and get back. Memory has proven false in the past. I can tell you this from personal experience, if we had bought it FOR the USAAC, we would not have been disappointed. Solidly built, solid performance, and a good aircraft.

However, if I had been in the procurement function, I might not have bought it for the USAAF in large numbers due to the quality of current equipment in the pipeline and the probability of the war winding down. We had the P-38, P-39. P-40, P-47, P-51, P-61, and P-80 jet and the war was being won. Should you create another logistics chain and train a new bunch of A&P mechanics with the war in the state it was in? Especially with jets on the way? Tough call even thought I LIKE the P-63.

We'll have one (the Palm Springs bird) flying at our airshow next weekend as fas as I know. Come to Chino and see it and the rest.

We'll taxi our Yokosuka D4Y Judy, fly the Tora, Tora, Tora Val, the Boeing P-26 and Seversky AT-12 (a really great performer in the air), and have a LOT of WWII hardware in the air. We expect 4 or 5 P-38's ... and a P-63. Lotsa' stuff flying!

Might as well come and see it if you are anywhere close.

 

[wuzak]

http://www.wwiiaircraftperformance.org/P-63/P-63A_42-69417_TSCEP5E-1938.pdf

 

[CORSNING]

Hey tomo,

Back on Spitfire/Hellcat they are still discussing the Allison engine and Aozora posted neat published stuff. But I got out of there before anyone realized that they didn't put Allisons in Spits and Cats and blew up the whole off topic thing.

GregP,
I looked up the Yokosuka D4Y at the museum. One article says it was originally had an Aichi Atsuta Liquid cooled V-12. Is that right? (I know I'm off topic already, but I want to know.)

Jeff

 

[CORSNING]

I read the report on the P-63A-9 42-69417 and studied the graphs. On the performance sheets I've worked up it looks like this:

9/21/44
V-1710-93 / 1,820 hp. / 75"Hg

Height..Speed/Climb
Meters...mph/fpm
S.L........366/3600
.1,000...376/3690
.2,000...385/3655
.3,000...392/3525
.4,000...397.5/3360
.5,000...400/3060
.6,000...394/2695
.7,000...390/2240
.8,000...386/1830
.9,000...381/1460
10.000..377/1045
11,000..370/650
12,000..342/240

Maximum velocity: 400.5mph/16,000 ft.

Combat Ceiling (1000fpm): 33,200 ft.
Operational Ceiling (500fpm): 37,200 ft.
Service Ceiling (100fpm): 40,400 ft.
Combat Weight: 8,950 lbs.
Wing Load: 39.09-lbs./sq.ft.
Power Load: 4.918-lbs./hp.
Armament: 1x37mm + 4x0.5in.

 

[tomo pauk]

Thanks for the feedback, people.

 

[CORSNING]

One of the graphs on Mike's sight is headed "Bell Aircraft Corp. - SOURCE". The information under the heading Condition 1 reads: P-63A, 8168 lbs G.W., Allison V-1710-93 (E-11), 11.0' SHORT SHANK PROP., WER USED; ARMY FLIGH TEST DATA. I am not sure what to make of this part of the graph dated: REC'D 4 DEC 43 FROM JFP.
Condition 1 works out something like this:
V-1710-93 / 1,460 hp. / ?"Hg

12/4/43
Height...Speed/Climb
Meters....mph/fpm
S.L........347/4000
.1,000...360/3995
.2,000...372/3950
.3,000...382/3880
.4,000...397/3730
.5,000...402/3490
.6,000...409/3070
.7,000...415/2660
.8,000...412/2240
.9,000...404/1850
10,000..393/1430
11,000..382/1040
12,000..N.G./660

Maximum Roll Rate: 110deg./sec.

Combat Ceiling: 36,500 ft.
Operational Ceiling: 40,600 ft.
Service Ceiling: 43,600 ft.

Combat Weight: 8,168 lbs.
Wing Load: 32.935 lbs./sq.ft.
Power Load: 5.595 lbs./hp.
Armament: 1x37mm + 4x0.5in.

Jeff

 

[eagledad]

Hello!

From what I have read, the P-63's major problem was that it lacked range on internal fuel. It was this feature that played the biggest role with the US not using the P-63 in a combat role. The P-63A-1/5 carried only 136 gallons of fuel internally, compared to 184 gallons in a P-51B-1, 300 gallons in a P-38J-1, 269 gallons in a P-51B-5, 420 gallons in a P-38J-15, and 305 gallons in a P-47D-20. An Air Force Test run at Eglin AF Base in March of 1944, gave the P-63 a combat radius at 25000 feet of only 65 miles on internal fuel, and 340 miles at 20000 feet on internal fuel + a 75 gallon drop tank. Of course, the P-63's radius would be even greater at a lower altitude.

Eagledad

Eagledad

 

[CORSNING]

eagledad,

That is absolutely correct. While the P-63 was capable of cruising low/slow for over 2,500 mls and more, BUT once it dropped its exterier fuel tanks it was limited to about 500 - 600 mls.

Jeff

 

[CORSNING]

The following information is taken from GRAPH 52 located in AHT. It is the MFR. data for the P-63A-8.

V-1710-93w / 1,800 hp. / 75"Hg?
No Date given.
Height....Speed/Climb/Time to climb
Meters....mph/climb rate/Time to height
S.L........378/4900/----
.1,000...393/4775/--.7
.2,000...405/4575/-1.4
.3,000...413/4325/-2.0
.4,000...420/3970/-2.7
.5,000...424/3520/-3.45
.6,000...423/2925/-4.6
.7,000...418/2500/-5.9
.8,000...414/2095/-7.35
.9,000...407/1675/-9.15
10,000..393/1180/11.15

Combat Ceiling (1000fpm): 34,060 ft.

Combat Weight: 8,213 lbs.
Wing Load: 33.117 lbs./sq.ft.
Power Load: 4.56 lbs./hp.
Armament: 1x37mm + 4x0.5in.

This graph also includes USAAF DATA, P-63. The numbers look real close to CONDITION 1 numbers from the Bell graph dated 4 DEC 43 that I have already posted. I have done workups on P-63A w/water injection, P-63C-1, P-63D and P-63E-1 but they are all from graphs that were calculated. I am out of time right now but could post those also if anyone is interested.

tomo,
I posted the P-63A-10 on the SPITFIRE/HELLCAT thread, but will post it more completed here if you would like. Let me know.

Thanks for the intrest Guys, Jeff

 

[tomo pauk]

Bring them on, Jeff, appreciate it

 

[CORSNING]

I had to go back to the other post and correct the Combat (1,000 fpm)/Service (100 fpm) ceiling numbers. Sorry Guys, I was at work on breaks. These following figures are from the graph COMPARATIVE PERFORMANCE OF P-63 AIRPLANES. It is dated 5 JUNE 1944. This is close to the time that the A-10 would be in the testing stages so I do not know if this is actual or calculated data.

P-63A-10 6/05/44
V-1710-93w / 1,825 hp. / ~75"Hg

Height....Speed/Climb/Time
Meters...mph/fpm/to height
S.L........383/4980/-----
.1,000...394/4825/--.6
.2,000...407/4625/-1.4
.3,000...415/4350/-2.1
.4,000...421/3950/-2.9
.5,000...423/3450/-3.9
.6,000...422/2950/-4.9
.7,000...412/2525/-6.1
.8,000...407/1960/-7.6
.9,000...394/1500/-9.4
10,000..376/1025/11.8

Combat Ceiling: 32,900 ft.
Operation Ceiling: 36,250 ft.
Service Ceiling: 38,500 ft.

Armament: 1x37mm + 4x0.5in.
Wing Load: 34.645 lbs./sq.ft.
Power Load: 4.71 lbs./hp.

 

[GregP]

The "A" version of any plane isn't the best. Even the first Spitfire was a shadow of the ones being flown in 1944. According to WWIIaircraftperformance.org charts, they tested a P-63A-10, P-63C-1, and a P-63E-1 on 5 Jun1944. This site seems to be quoted a lot in this forum, so I'll use it. The results were as follows:

1) P-63A-10: Top speed was 423 mph at 17,500 feet. Initial rate of climb was 5,000 feet per minute.

2) P-63C-1: Top speed was 434 mph at 18,250 feet. Initial rate of climb was 4,700 feet per minute.

2) P-63E-1: Top speed was 445 mph at 25,000 feet. Initial rate of climb was 4,500 feet per minute.

This is from the second chart down in this page: P-63 Performance Tests . The primary text on this page is about the XP-63A, none of which ever saw service. The charts show which variants are for which curves. The first chart down shows 422 mph. The third chart down is interesting. It shows a comparison of the P-63A, P-63C-1, and P-63D. It shows the P-63A at 415 mph Military power, 431 mph at WER, and the P-63D at 450 mph or so (I doubt this speed and would like to see the test conditions, weights, etc.). The chart says all models had wing guns but there is very little in the way of specifics such as weight, finish, and configuration. I am suspicious of charts without a clearly readable document number. I won't say this chart is wrong, but also won't hang much confidence on it.

Other tests showed the P-63A-10 about 410 mph in some cases and about 420 in others. Ray Wagner in "American Combat Planes" has the P-63A at 408 mph but does not give a dash number. That speed corrresponds within 2 mph with a P-63A-9 test that I have seen. He also has the P-63D at 437 mph, but that was a one-off bubble canopy test mule.

So … the data are all over the place with top speeds from 408 mph to 445 mph depending on variant. To me a 37 mph top speed variation shows these planes were in different configurations and were probably not all that similar to one another. I could be wrong here, but it appears the Bell P-63 series in General wasn't all that well documented, no doubt since most were going to the Soviet Union. The performance of front line fighters was rarely as good as for factory fresh planes since they sat outside, got dirty, and had normal wear and tear glitches. Maybe what we're seeing in these data are a few fresh planes with some well-used and not immaculatey-maintained units thrown into the mix. In any case, all the charts show the P-63 outclimbing the P-51 and being a bit slower at best altitude while being about equal at sea level. All the charts show 408+ mph top speeds ... the text in places simply doesn't agree with the charts.

The Russians loved the Kingcobra and the USAAF never particularly embraced it. Being at the end of the piston fighter era, it never got the chance to show itself to its home country's air force. In retrospect, the Bell P-63 probably wasn't even needed since the war wqas being won with existing equipment.

 

[tomo pauk]

The chart might be dated 5 Jun1944, but that does not mean the curves were result of the flight test - maybe they were manufacturer's estimates. The 1st P-63C was delivered to the USAF in December 1944, the 1st P-63E in May 1945.
The different versions of the P-63 were equipped with distinctively different engines, so the spread in top speed should be notable, once the planes were above 25000 ft. Not just the auxiliary supercharger drives were different, the placing of the carburetor was changed, and the max rpm was upped to 3200.

The Russians loved the Kingcobra

Disagree - they insisted the airframe was too weak, so Bell reinforced the fuselage, and produced reinforcing kits that were to be installed on delivered planes.

In retrospect, the Bell P-63 probably wasn't even needed since the war wqas being won with existing equipment.

+1 on that.

 

[CORSNING]

These figures come from the BELL AIRCRAFT CORP.-SOURCE graph and are listed under CONDITION 2. In this section it also states: WER WITH ALCOHOL-WATER INJECTION DATA CALCULATED MODIFIED TO CORRESPOND TO FLIGHT TESTS WITH RAM.

12/04/43
P-63 W/W.I.
V-1710-93w / 1,800 hp.? / ?

Height...Speed/Climb
Meters..mph/fpm
S.L.......381/4600
.1,000...393/4460
.2,000...402/4280
.3,000...412/4060
.4,000...419/3880
.5,000...427/3440
.6,000...430/3070
.7,000...423/2260
.8,000...414/2240
.9,000...404/1850
10,000..393/1430
11,000..382/1040

Combat Ceiling: 36,500 ft.
Operational Ceiling: 40,600 ft.
Service Ceiling: 43,600 ft.

Armament: 1x37mm + 4x0.5in.
Wing Load: 33.266 lbs./sq.ft.
Power Load: 4.583 lbs./hp.
Combat Weight: 8,250 lbs.

You will notice that climb rates starting around 8,000 m and speeds around 9,000 m are the same as the P-63A without water injection from this graph. No time to height graph was provided.

 

[CORSNING]

There definitely was a problem with the airframe and it was corrected in the A-7 I believe. I don't have time now to look it up but I believe all corrections were made BEFORE large supplies of the A/C were sent to USSR.
AND as far as I can tell ALL weights of the A/Cs are given on the graphs. Keep in mind some of these graphed A/C are calculated.

 

[CORSNING]

V-1710-117w / 1,800 hp.

Height...Speed/Climb/Time
Meters..mph/fpm/to height
S.L.......381/4650/----
.1,000...394/4575/--.6
.2,000...407/4480/-1.4
.3,000...417/4270/-2.1
.4,000...428/3950/-2.9
.5,000...433/3450/-3.9
.6,000...434/2950/-4.9
.7,000...432/2550/-6.1
.8,000...427/2000/-7.6
.9,000...419/1550/-9.4
10,000..407/1080/11.8
11,000..N.G./600/N.G.
12,000..N.G./175/N.G.

Combat Ceiling: 32,900 ft.
Operational Ceiling: 37,000 ft.
Service Ceiling: 39,750 ft.

Armament: 1x37mm + 4x0.5in.
Wing Load: 36.02 lbs./sq.ft.
Power Load: 4.96 lbs./hp.
Combat Weight: 8,933 lbs.

 

[CORSNING]

Its time to set the record straight. The USAAF didn't buy into the P-63 because they just didn't need it. They were covered with the P-51, P-47 and P-38. And then there is the P-80, JETS. They just didn't need another prop venture. The USSR was not disappointed with P-39 because it could match the opposition at the heights they needed it to fight. The P-63 could continue to match the newer opposition and they were made available to them.

Now on the graph thing. I have been studying performance graphs very closely for over two years now. (Looking at them waaaay longer than that). It is extremely helpful if a chart is provided so that the lines on the graph can be more accurately translated. This is not always the case. I have notice that most performance indicating graph lines no matter how narrow or wide, are usually (not always) centered on the exact figure they are representing. Many times I have enlarge a graph 400 % to get more accurate readings. The speeds I have listed are within 1 mph (definitely no more than 1 mph off). The climb rates are much rougher to narrow down and I do the best I can to keep them within 5 fpm. On graphs the right edge of the vertical line is the starting point for whatever number it is representing.

That being said, I can safely say that the climb rates of the A-10, C-1 and E-1 are a lot closer to 4980, 4650 and 4450 than they are 5000, 4700 and 4500 respectively.

You Guys all have a good night. I'm signing off for today, Jeff

 

[GregP]

Many charts show speed but don't tell you if it is IAS, CAS or TAS, and some don't tell you if the speeds shown are mph or knots!

It's much easier to tell if the speeds are in kph since the numbers will jump out at you ... anything over 490 or so has to be kph for a propeller plane in WWII.

I stilil want document numbers that I can find somewhere else besides ONE place on the internet ... but sometimes it just isn't there.

 

[CORSNING]

GregP,
Do you want numbers that all the publishers are pushing around in publication or do you want the numbers from the original documents that the masses have bypassed in order to get the book published on time? All the charts I have studied are very specific about metric or english measure. I actually haven't seen any authentic ones that aren't. If you wish to believe the P-51D's maximum speed is 437 mph and the P-47D's is 429 mph, go for it. Personally I'm going to do the best I can at digging up the truth even if it hurts. That's exactly what I have been doing for quite some time. I have compiled graph information on several Spitfires, Mustangs, Fw-190s, Hurricanes, Zekes, Tonys, etc. etc. etc..... and plan to continue.

Have a good night, all of you, Jeff