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View Full Version : Hey Robban- some new (and timely) P-51D test data



lrrp22
01-16-2006, 04:17 PM
Mike Williams of spitfireperformance.com has uncovered some very detailed test data for the P-51D. The P-51 seems to be a hot topic of late, so this data might prove useful.

http://www.spitfireperformance.com/mustang/p51d-15342.html

Here's a quick synopsis- all data for full combat load with wing racks fitted, but only 25 gallons of fuel in the 85 gallon fuselage tank (81% fuel):

Speeds

0 meters/ft- 603kph/375mph
1000/3281 - 628/390
2000/6562 - 650/404
3000/9843 - 669/416
4000/13123 - 665/413
5000/16404 - 658/409
6000/19685 - 676/420
7000/22966 - 694/431
7925/26000 - 711/442

Add 12-13 kph at sea level up to about 20-21 kph at high altitude for speeds without wing racks.

An interesting aside- it looks like 4th FG Ace Don Gentile was one of the two test pilots...

LRRP

lrrp22
01-16-2006, 04:17 PM
Mike Williams of spitfireperformance.com has uncovered some very detailed test data for the P-51D. The P-51 seems to be a hot topic of late, so this data might prove useful.

http://www.spitfireperformance.com/mustang/p51d-15342.html

Here's a quick synopsis- all data for full combat load with wing racks fitted, but only 25 gallons of fuel in the 85 gallon fuselage tank (81% fuel):

Speeds

0 meters/ft- 603kph/375mph
1000/3281 - 628/390
2000/6562 - 650/404
3000/9843 - 669/416
4000/13123 - 665/413
5000/16404 - 658/409
6000/19685 - 676/420
7000/22966 - 694/431
7925/26000 - 711/442

Add 12-13 kph at sea level up to about 20-21 kph at high altitude for speeds without wing racks.

An interesting aside- it looks like 4th FG Ace Don Gentile was one of the two test pilots...

LRRP

faustnik
01-16-2006, 04:30 PM
Nice! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Can't wait to redraw those!

ICDP
01-16-2006, 05:05 PM
Nice link and a good read LRRP.

I read this and got testing with the P51D-N20. Crimea map with 100% fuel 12:00 noon, 100% ammo and no wing racks. All speeds are TAS.

Top speed SL: 597kph 371(mph)

Speed at 26000ft: 714kph (444mph)

All in all quite close to the speeds from the test you posted the link to. All the P51 needs is the un-synched .50mgs and the wobble fixed http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

lrrp22
01-16-2006, 05:36 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
Nice link and a good read LRRP.

I read this and got testing with the P51D-N20. Crimea map with 100% fuel 12:00 noon, 100% ammo and no wing racks. All speeds are TAS.

Top speed SL: 597kph 9371(mph)

Speed at 26000ft: 714kph (444mph)

All in all quite close to the speeds from the test you posted the link to. All the P51 needs is the un-synched .50mgs and the wobble fixed http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

If you want a sobering suprise, add wing racks and try again! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif


Seriously though, the new numbers are definitely at the upper range of tested data but it is USAAF *test* data (not manufacturer) of a production example that has been instrumented and corrected to NACA standard conditions.

LRRP

robban75
01-20-2006, 04:33 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lrrp22:
Mike Williams of spitfireperformance.com has uncovered some very detailed test data for the P-51D. The P-51 seems to be a hot topic of late, so this data might prove useful.

http://www.spitfireperformance.com/mustang/p51d-15342.html

Here's a quick synopsis- all data for full combat load with wing racks fitted, but only 25 gallons of fuel in the 85 gallon fuselage tank (81% fuel):

Speeds

0 meters/ft- 603kph/375mph
1000/3281 - 628/390
2000/6562 - 650/404
3000/9843 - 669/416
4000/13123 - 665/413
5000/16404 - 658/409
6000/19685 - 676/420
7000/22966 - 694/431
7925/26000 - 711/442

Add 12-13 kph at sea level up to about 20-21 kph at high altitude for speeds without wing racks.

An interesting aside- it looks like 4th FG Ace Don Gentile was one of the two test pilots...

LRRP </div></BLOCKQUOTE>

Very interesting! http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

How do these "new" top speeds compare to other tested Mustangs? Was this Mustang specially picked? Or was it just another Mustang? And was it specially prepared? http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

616km/h SL speed at WEP! Would that be with 1720hp? A well polished D-9 would probably need almost 2200hp to reach that speed! http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

robban75
01-20-2006, 04:36 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lrrp22:
If you want a sobering suprise, add wing racks and try again! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
</div></BLOCKQUOTE>

Ah, yes, the Mustang(any version) loses tons of speed when the racks are fitted! http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

It's a major bug!

Slickun
01-20-2006, 08:32 AM
Wow. Unbelievably fast compared to the contemporary "437" we are all so familiar with.

442 WITH wing racks? that is screaming.

Note all the speeds are with racks and 67" hg.

Nice find, lrrp!

lrrp22
01-20-2006, 05:47 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by robban75:
Very interesting! http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

How do these "new" top speeds compare to other tested Mustangs? Was this Mustang specially picked? Or was it just another Mustang? And was it specially prepared? http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

616km/h SL speed at WEP! Would that be with 1720hp? A well polished D-9 would probably need almost 2200hp to reach that speed! http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif </div></BLOCKQUOTE>

Hiya Robban,

That's a stock P-51D-15-NA in full combat configuration at 9,760 lbs and 67" Hg/1700 BHP. The purpose of the test was to confirm the values in the Flight Operating Instructions so stock service condition was required. All performance numbers are reduced to standard NACA atmospheric conditions.

Those speeds are definitely on the upper end of what might be expected for that configuration but well within the normal 2-3% variation. The 26,000 ft high blower critical altitude is a bit higher than normally quoted 24,500 to 25,000 ft and that accounts for an extra 2-3 mph, but again, its nothing special.

One thing to note- this and all other USAAF Mustang performance tests are conducted with the radiators set to 'Auto'. These top speeds were all achieved with the Oil Cooler flap and Radiator Flap slightly open. As you know, to reach max speeds in PF radiators must be fully closed.


LRRP

lrrp22
01-20-2006, 06:18 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by robban75:

How do these "new" top speeds compare to other tested Mustangs? Was this Mustang specially picked? Or was it just another Mustang? And was it specially prepared? http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif </div></BLOCKQUOTE>

Here's a quick comparison with P-51B-15-NA 43-24777 in an almost identical configuration as 44-15342. All speeds in feet/mph:

SL-- 364, 375 3% difference
5k-- 385, 396 2.8%
10k- 408, 417 2.2%
15k- 404, 411 1.7%
20k- 414, 421 1.7%
24k- 426, 435 2.1%
26k- 424, 442 4.1%

24,000 ft is 43-24777's high blower full throttle height which is on the lower end of the range. That accounts for the bigger difference at 26k.

So basically, 43-24777 and 44-15342 probably represent the lower and upper end of normal performance for that configuration.

LRRP

Slickun
01-20-2006, 09:29 PM
Well, lrpp, the tests are at a lower weight than most we see. Nearly all the tests are done at well over 10,000 pounds.

The test you published is a configuration many LW fighters faced....a lot of fuel burned off, wing racks.

442 with a fuselage tank over half empty and wing racks.

SithSpeeder
01-21-2006, 09:35 AM
Wow, great find.

At that same site, if you go up a bit in the structure, you'll find a lot more Mustang variant data (including the Mustang III).

OK, so it looks like the top level speed is undermodelled in our game as well.

* _54th_Speeder *

lrrp22
01-21-2006, 11:01 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SithSpeeder:

OK, so it looks like the top level speed is undermodelled in our game as well.

* _54th_Speeder * </div></BLOCKQUOTE>

Sith,

I wouldn't go that far. That P-51D test is definitely at the upper end of the normal range- a few mph less in-game can't be called wrong. The P-51B/C are a few mph too slow at altitude, but the Mustang III is too fast.

I would like to see the P-51 reach its top speeds with radiators set to auto though. It would also be nice if it didn't pay such a huge price for wing racks but that is something we're stuck with 'til BoB.

LRRP

SithSpeeder
01-22-2006, 12:02 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Add 12-13 kph at sea level up to about 20-21 kph at high altitude for speeds without wing racks. </div></BLOCKQUOTE> lrrp--you don't think that's significant? To me, that's the difference between getting hunted down and outlasting them in a firewalled extension.

From another thread...
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Robban75 posted these, thanks Thumbs Up

Alt -- K-4 - P51 - La7 - D-9 - D-9'45

0m --- 590 - 608 - 612 - 614 - 621
1000 - 602 - 618 - 627 - 631 - 632
2000 - 624 - 646 - 643 - 643 - 628
3000 - 650 - 677 - 630 - 650 - 655 </div></BLOCKQUOTE>
At 0m, adding 12-13 kph puts the 51D tied with the D-9'45, right?

I remember running from a TA (admittedly not a D-9'45, but hear me out) after bouncing some of his buddies. I ran at 3000m. He slowly closed on me, trying to pepper me from long range. After this went on for about 5 minutes, he said his engine was overheating. Two minutes later, he had to bail as the engine went into its death throes. The chase shouldn't have even happened because he shouldn't have been able to close on me. YMMV.

* _54th_Speeder *

luftluuver
01-22-2006, 05:28 AM
Good find Lrrp.

A big <span class="ev_code_YELLOW">THANKS</span> http://forums.ubi.com/images/smilies/25.gif to Neil and Mike for making this data available on their site. Where would we be without them? http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Hetzer_II
01-22-2006, 05:36 AM
"Where would we be without them? Wink"

we would be where we are.. so....

geetarman
01-22-2006, 08:47 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Hetzer_II:
"Where would we be without them? Wink"

we would be where we are.. so.... </div></BLOCKQUOTE>

so -- it's nice to find a site that has good info on mustangs - got a problem with that?

VW-IceFire
01-22-2006, 08:55 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lrrp22:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SithSpeeder:

OK, so it looks like the top level speed is undermodelled in our game as well.

* _54th_Speeder * </div></BLOCKQUOTE>

Sith,

I wouldn't go that far. That P-51D test is definitely at the upper end of the normal range- a few mph less in-game can't be called wrong. The P-51B/C are a few mph too slow at altitude, but the Mustang III is too fast.

I would like to see the P-51 reach its top speeds with radiators set to auto though. It would also be nice if it didn't pay such a huge price for wing racks but that is something we're stuck with 'til BoB.

LRRP </div></BLOCKQUOTE>
Certainly a few MPH deviation between test data and the game is a minor issue at best and really not something that we should worry about. When were out 15 or 25 mph on any aircraft then there is a more serious deviation.

I'm still not convinced that the ultra boosted Mark III is too fast...I mean it was meant to be too fast really http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Slickun
01-22-2006, 10:37 AM
405 on the deck, after a little bit of paint re-do on the wings.

That was a squadron plane, well used, that got 405 on the test. A few more mph were squeezed out with a couple of simple mods, like Spitfire stacks and some sort of antenna base or something.

IIRC the Tempest and Mark 14 that were also tested had severe problems with operating at high boosts. Did one catch fire or something?

luftluuver
01-22-2006, 02:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Slickun:
IIRC the Tempest and Mark 14 that were also tested had severe problems with operating at high boosts. Did one catch fire or something? </div></BLOCKQUOTE>

No the Tempest, and Typhoon, did not catch fire from using high boost. They caught fire even when using 9lb boost. Had nothing to do with the boost pressure.

Slickun
01-22-2006, 07:08 PM
I think they actually caught fire during the high boost test.

luftluuver
01-22-2006, 09:46 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Slickun:
I think they actually caught fire during the high boost test. </div></BLOCKQUOTE>I didn't know that combat missions were classed as testing.

Slickun
01-23-2006, 07:29 AM
Ah.

I get it!

http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

It just took me awhile, thanks for showing patience.

lrrp22
01-23-2006, 09:35 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VW-IceFire:
I'm still not convinced that the ultra boosted Mark III is too fast...I mean it was meant to be too fast really http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I mean at higher altitudes- it should be just about as fast as the P-51D at high altitude but it is *much* faster at 25,000 ft. <span class="ev_code_YELLOW">*</span> It's good at lower altitudes.

LRRP

<span class="ev_code_YELLOW">*</span>However...with rads set to auto I believe it hits right around 710 kph, which is right where it should be. Since all top speed tests were conducted with rads set to Automatic, it may be right while the P-51B/C/D's may be too slow in that regard.