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stalkervision
06-28-2008, 03:52 PM
Is the max speed with "wep" or without "wep" included? http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif

if so what is it's max speed without "wep"

ElAurens
06-28-2008, 06:09 PM
In game or in real life?

stalkervision
06-28-2008, 06:15 PM
Originally posted by ElAurens:
In game or in real life?

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

Bearcat99
06-28-2008, 06:16 PM
That's a good question... I am curious myself.

stalkervision
06-28-2008, 06:24 PM
I'm a total p-51 newbee. I always see max speed for the 51 but it just occured to me is this with or without wep? http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif

Brain32
06-28-2008, 06:56 PM
OK, OK, what is happening here? A gang fishing trip? http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

ElAurens
06-28-2008, 07:37 PM
Ok, my copy of "America's Hunderd Thousand" says that P51 top speed numbers are at War Emergency Power.

luftluuver
06-28-2008, 07:40 PM
Originally posted by ElAurens:
Ok, my copy of "America's Hunderd Thousand" says that P51 top speed numbers are at War Emergency Power.

At what boost?

berg417448
06-28-2008, 07:44 PM
Lots of Mustang info here:


http://www.spitfireperformance.com/mustang/mustangtest.html

Skoshi Tiger
06-28-2008, 07:58 PM
The problem with determining the Maximum speed of the mustang (or any other aircraft for that matter) is that when one wing falls off, the resultant asymetrical configuration causes the aircraft to decelerate and LOOSE speed!

Has anyone had both wings fall off at exactly the same time and experienced acceleration due to the reduction of induced drag caused by the wings?

stalkervision
06-28-2008, 08:15 PM
Originally posted by berg417448:
Lots of Mustang info here:


http://www.spitfireperformance.com/mustang/mustangtest.html

Thanks buddy. It just might be here. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ElAurens
06-28-2008, 09:17 PM
"America's Hundred Thousand" lists these boost pressures in HG".

For the V-1650-3, and V-1650-7:
Normal 46
Military 61
Combat 67

The V-1650-9 as used in P51H raises the combat boost to 80" HG.

Skoshi Tiger
06-28-2008, 11:17 PM
Originally posted by ElAurens:
"America's Hundred Thousand" lists these boost pressures in HG".

For the V-1650-3, and V-1650-7:
Normal 46
Military 61
Combat 67

The V-1650-9 as used in P51H raises the combat boost to 80" HG.

So when you read those WWII pilots talking about pulling 70" of mercury , They were seriously thrashing their engines! I wonder if they told their maintenance crew?

JtD
06-29-2008, 12:47 AM
The boost allowance for the P-51 was different. At some time, there were 60" (-3 engine), at some time up to 80" boost allowed. Also depended on the theatre of operation and the role the fighters were in. Technical background would be the quality of the fuel, but there were also service experience / maintenance quality as well as tactical considerations. It's thus a bit pointless to look for the max. speed, as there were many.

ElAurens
06-29-2008, 06:45 AM
http://forums.ubi.com/images/smilies/agreepost.gif

Absolutely.

For instance there is no mention in AHT about the boost levels of Pacific P51s running 150 fuel, the Mustangs at Iwo ran quite high max MP as I recall.

And then there is the difference in airframes, not jsut the difference between B/C and D models (B/C were faster), but external equipment, I.E. bomb and or rocket racks.

There really is no one absolute figure for top speed of any military aircraft, especially aircraft in the field.

scaredycat1
06-30-2008, 09:43 PM
Originally posted by Skoshi Tiger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ElAurens:
"America's Hundred Thousand" lists these boost pressures in HG".

For the V-1650-3, and V-1650-7:
Normal 46
Military 61
Combat 67

The V-1650-9 as used in P51H raises the combat boost to 80" HG.

So when you read those WWII pilots talking about pulling 70" of mercury , They were seriously thrashing their engines! I wonder if they told their maintenance crew? </div></BLOCKQUOTE>

I think there was a piece of wire across top end of the the throttle track, if you pushed above 100% it broke the wire, so the crew chief would know.

Dustysquareback
07-01-2008, 11:49 AM
Originally posted by scaredycat1:
I think there was a piece of wire across top end of the the throttle track, if you pushed above 100% it broke the wire, so the crew chief would know.

Yup. My grandfather broke through his (P-51C, CBI) running from a Tojo on the deck. The crew chief was miffed - but when he saw the 13mm holes in his tail - he forgave him http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

BigKahuna_GS
07-03-2008, 03:17 PM
For instance there is no mention in AHT about the boost levels of Pacific P51s running 150 fuel, the Mustangs at Iwo ran quite high max MP as I recall.

And then there is the difference in airframes, not jsut the difference between B/C and D models (B/C were faster), but external equipment, I.E. bomb and or rocket racks.

There really is no one absolute figure for top speed of any military aircraft, especially aircraft in the field.
__________________________________________________ __________________________________________________ __________________________________________________ ___



The P51's on Iwo Jima operated on 115/145grade fuel and 81"MAP/HG.

The RAF Mustang Mark III & Mark IV were combat flown at 25lbs overboosted grade150 fuel. US 8thAF P51s operated at 75"MAP/HG on 150grade fuel.

The Corsairs on the fast carriers that were tasked with Kamikaze intercept ran on 115/145grade fuel and were overboosted to 65"MAP conservative and
possibly as high as 70" MAP. I have been trying to track down docs confirming this. This was according to Corsair combat pilots.

http://www.wwiiaircraftperformance.org/mustang/mustang-tactical.html

BOOST PRESSURE CONVERSION TABLE

Inches of HG Lbs. per SQ/IN.
22"------------------------ -4
26"--------------------------2
30"--------------------------0
34"-------------------------+2
38"-------------------------+4
44"-------------------------+7
48"-------------------------+9
54"------------------------+12
60"------------------------+15
67"------------------------+18


Mustang Mark III Max Climb on 150 grade fuel & 25Lbs boost ---very nice climb rate increase.

http://www.spitfireperformance.com/mustang/fx858-fig-4.jpg


Mustang Mark III max speed on 150 grade fuel & 25lbs boost (18lbs boost performance was estimated)

http://www.spitfireperformance.com/mustang/fx858-fig5.jpg

Viper2005_
07-03-2008, 06:22 PM
450 mph TAS is a reasonable approximation.

As pointed out on the front page of the original "Spitfire Performance" Website:


Any particular machine off the production line, however, may vary from the average in top speed and climb because of differences in engine power and general finish. The usual variation for single-engined fighters is up to 3% in top speed, and 150-200 ft./min. in rate of climb; heavy bombers vary up to 4% in top speed, and 150-200 ft./min. in climb.

http://www.spitfireperformance.com/spittest.html

3% of 450 mph is 13.5 mph.

That is without even starting to consider the effect of different fuel & ordnance loads, not to mention "local" mods...

As to boost, the reality is that superchargers were generally optimised for the top right-hand corner of the envelope (i.e. FTH).

Below FTH you can get more power from extra boost if the rest of the engine can handle it, but you also get more drag roughly in proportion. As such, top speed remains roughly at the number you first thought of.

IRL you win slightly because of the increased Reynolds number and reduced prop helical tip Mach number.

However, quite a lot of period charts for boosted aeroplanes were simply extrapolated by extending a vertical line down from the top speed at the original FTH to the FTH at the new boost limit. Good enough for Government Work.

***

This engineering perspective is and was of only limited relevance to the fighter pilot.

Air combat is rather like poker in the sense that it is a game played for high stakes upon the basis of extremely imperfect information.

If "Janes" says that my aeroplane can out run yours in straight and level flight at whatever altitude, what that really means when the metal meets the meat (in a guns fight at the edge of reasonable guns range) is that if I run I've got a somewhat better than even chance of getting away from you. I might be unlucky; you might have more E than I thought, your aeroplane might be "above average" (as might your technique), or whatever...

Anyway, if you do a good job, the other guy never sees you. You kill him whilst he's cruising & enjoying the view.

<span class="ev_code_red">Never forget that the objective of the exercise is to kill (or at least disable) the enemy, not to fight him.</span>