PDA

View Full Version : Mustang III performance issues



Viper2005_
01-27-2006, 11:32 AM
The Mustang III is too fast at altitude.

It appears that it has 81" Hg performance whilst only drawing 70" Hg. This isn't just a boost gauge issue, as the supercharger gear change takes place at the wrong height too.

At 81" Hg (+25 psi boost) full throttle height in MS gear should be about 8,000 feet, with supercharger gear change taking place at around 12,000 feet. Full throttle height in FS gear should be around 20,000-21,000 feet.

In game, supercharger gear change takes place at about 15,000 feet which is exactly what one might expect were the engine rated at 70" Hg.

Full throttle height in FS gear in game is about 25,000 feet.

This means that excessive performance is available between about 8,000 feet and 15,000 feet, and again above about 20,000 feet. By 25,000 (7500 m) feet the aircraft is capable of very excessive speeds (~770 km/h according to wonder woman view on the crimea map).

It seems that the P-51C was given extra power to turn it into a Mustang III without alteration of the engine's full throttle height.

<span class="ev_code_RED">This issue is especially important if we're going to get a +25 psi Spitfire as the same pitfall awaits.</span>

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

Brain32
01-27-2006, 12:45 PM
You did not say P51 was best at everything and you even try to prevent same thing happening with the mew Spitfire, now watch your thread being ignored.
I for one completely agree with you, this issu has been mentioned before and Robban made the tests: http://forums.ubi.com/eve/forums/a/tpc/f/63110913/m/7321095783

robban75
01-27-2006, 01:54 PM
Originally posted by Brain32:
Robban made the tests:

I'd just like to add that I have always made tests with wind and turbulence on. For speeds without wind, detract 6-8km/h from the top speed.

The speed test below is made without wind and turbulence.

Crimea, full fuel default loadout, rads closed. In meters and km/h(TAS).

Mustang III

SL - 650
1K - 675
2K - 705
3K - 730
4K - 730
5K - 720
6K - 760
7K - 771

The Mustang III, as well as P-51B/C/D, lose between 40 and 60(!) km/h in top speed with wing racks fitted! http://forums.ubi.com/images/smilies/blink.gif

XyZspineZyX
01-27-2006, 02:52 PM
Airspeed isnt dependant on wind. So with or without wind you would get the exact same figures.

robban75
01-27-2006, 03:13 PM
Originally posted by Skunk241981:
Airspeed isnt dependant on wind. So with or without wind you would get the exact same figures.

IAS isn't, but TAS is affected(in-game) when wind is turned on.

For example, with wind I get 621km/h at sealevel with the D-9'45. With wind off I get 612km/h. Perhaps true airspeed really is ground speed. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Willey
01-27-2006, 03:27 PM
621 in the 45? I always thought the 44 was faster, like the real one - and like the previous FB versions... should test them again, as well as the P-47 25lb vs the D-27 (can't see any speed and climb difference there, at least up to 3k)

Viper2005_
01-27-2006, 03:54 PM
I've posted a thread on the warclouds forums including a zipped track.

http://www.war-clouds.com/forums/viewtopic.php?p=3937#3937

p1ngu666
01-27-2006, 04:33 PM
http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif i didnt know it was too good up high

770 kph = 478.455818 mph

http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Von_Rat
01-27-2006, 08:13 PM
doesn't that make it faster than the ta152, even at the ta's best alt.

in other words its faster at 7500m than the ta152 is at its best alt, which is 9000m.

VW-IceFire
01-27-2006, 09:06 PM
As I understand it...the real overboosted aircraft gained performance at low altitudes and gain some performance all the way upto their best rated critical altitude and above that they were the same as the lower boosted versions.

This is true of the Spitfire LF.IX with 150 fuel/+25lb boost. I imagine this is also true of the Mustang Mark III with the same type of configuration. So the guess here is that the game is boosting power above best speed/critical altitude as well as at lower altitudes.

Am I correct? Does the graph only diverge after rated critical altitude?

The-Pizza-Man
01-27-2006, 10:58 PM
http://www.spitfireperformance.com/merlin66hpchart.jpg

The HP produced converges as it becomes supercharger limited rather than engine durability limited. You can see the big difference it would make at certain altitudes. At 12,000' a +25lb boosted engine is producing over 400 hp more than the +18lb engine. But there is no difference at 20,000' and beyond because the engine then becomes supercharger limited. So above 20,000' the Mustang III shouldn't be any faster than your stock standard boosted Mustang.

EDIT: I just took out the picture from spitfireperformance because I realised it had a big "do not distribute or copy" on it. You can just click on the link to look at it now

p1ngu666
01-27-2006, 11:55 PM
u could get the higher boost at higher alts, if u was going really fast, ud get more air into the engine then http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

im surprised its so good cos last time i flew it up high it seemed to lack umph http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif
even 190A's seemed better http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Von_Rat
01-28-2006, 01:09 AM
Originally posted by Viper2005_:
I've posted a thread on the warclouds forums including a zipped track.

http://www.war-clouds.com/forums/viewtopic.php?p=3937#3937

good work viper.

maybe this should be sent to oleg.

Viper2005_
01-28-2006, 12:15 PM
Originally posted by p1ngu666:
u could get the higher boost at higher alts, if u was going really fast, ud get more air into the engine then http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif


If you read the chart ( http://www.spitfireperformance.com/merlin66hpchart.jpg ) carefully you'll see that the data assumes 400 mph ram with 80% pressure recovery and 100% temperature recovery.

AFAIK the game accounts for ram pressure, so FTH increases at high speed. However because the Merlin (and most other late-war engines) were regulated by an automatic boost control unit you won't see more boost, just an increase in the FTH at high speed.

Viper2005_
01-28-2006, 12:24 PM
Email sent to the bug reporting address.

Bremspropeller
01-28-2006, 02:31 PM
I recon the Marque III has got the P-51H FM http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Viper2005_
01-28-2006, 03:32 PM
Having done the sums on this, the effect is almost identical to that which would be obtained by fitting the Mustang III with a Griffon 61 with a WEP rating of +18 psi @ 2750 rpm. Because the added weight of the Griffon isn't modelled it's somewhat optimistic, but never the less it's pretty close!

Xiolablu3
01-29-2006, 01:58 AM
Originally posted by p1ngu666:


im surprised its so good cos last time i flew it up high it seemed to lack umph http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif
even 190A's seemed better http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

I agree mate, I was trying to sort out the p51 wobbles last night and I was having a hard time catching a fw190A4 on the deck in the Mustang III http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

(Not scientific test of course, just me messing about in QMB.)

alert_1
01-29-2006, 04:52 AM
I agree, Fw190 should be town down a bit there are many pilots accounts how Fw190 wasnt even to get off the ground and in the Oleg world it's regularly shooting planes down. It need to be solved ASAP!
http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

robban75
01-29-2006, 05:00 AM
Originally posted by Xiolablu3:
I was having a hard time catching a fw190A4 on the deck in the Mustang III http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

(Not scientific test of course, just me messing about in QMB.)

That is interesting, since the Mustang III is more than 100km/h faster on the deck. http://forums.ubi.com/images/smilies/blink.gif

Kurfurst__
01-29-2006, 05:09 AM
There's nothing wrong with the Mustang III, it's just have been mislabeled. Should be P-51H. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

770, now that's an offender.

Re bomb racks, as per this test :

http://www.spitfireperformance.com/mustang/p51b-speed-wf.jpg

The speed loss to bomb racks was 8mph/13kph at SL, and 13mph/21kph at rated alt, so there's definietely too much loss from there if they kill 40-60kph.

Xiolablu3
01-29-2006, 05:16 AM
Originally posted by robban75:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
I was having a hard time catching a fw190A4 on the deck in the Mustang III http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

(Not scientific test of course, just me messing about in QMB.)

That is interesting, since the Mustang III is more than 100km/h faster on the deck. http://forums.ubi.com/images/smilies/blink.gif </div></BLOCKQUOTE>

I understand this mate, but it seems to take a very long time to get up to speed, plus if you are even slightly climbing it slows it down a lot.

I hardly ever fly the P51/Mustang because of the wobbles, so I am not a very good p51 pilot. Just my observation from a couple of quick QMB's last night.

Low_Flyer_MkII
01-29-2006, 06:12 AM
Might be of interest.

http://i6.photobucket.com/albums/y231/Low_Flyer/must01.jpg
http://i6.photobucket.com/albums/y231/Low_Flyer/must16.jpg
http://i6.photobucket.com/albums/y231/Low_Flyer/must17.jpg
http://i6.photobucket.com/albums/y231/Low_Flyer/must18.jpg

Viper2005_
01-29-2006, 10:26 AM
Wrong engine I'm afraid. The Mustang III in game has the V-1650-7. The V-1650-3 was never uprated to +25.

Low_Flyer_MkII
01-29-2006, 10:40 AM
I'll get my coat... http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

VW-IceFire
01-29-2006, 10:51 AM
Originally posted by Xiolablu3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p1ngu666:


im surprised its so good cos last time i flew it up high it seemed to lack umph http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif
even 190A's seemed better http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

I agree mate, I was trying to sort out the p51 wobbles last night and I was having a hard time catching a fw190A4 on the deck in the Mustang III http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

(Not scientific test of course, just me messing about in QMB.) </div></BLOCKQUOTE>
Thats odd...his top speed is going to be so much lower that it'll look like he's standing still.

Viper2005_
01-29-2006, 11:18 AM
I'm sorry if my reply came across as a little terse Low_Flyer. I've got the same set of notes myself, but I've never been able to lay my hands on notes for the Mustang III fitted with the V-1650-7 which is most frustrating!

Low_Flyer_MkII
01-29-2006, 11:24 AM
No worries mate http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

p1ngu666
01-29-2006, 11:30 AM
Originally posted by VW-IceFire:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p1ngu666:


im surprised its so good cos last time i flew it up high it seemed to lack umph http://forums.ubi.com/groupee_common/emoticons/icon_confused.gif
even 190A's seemed better http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

I agree mate, I was trying to sort out the p51 wobbles last night and I was having a hard time catching a fw190A4 on the deck in the Mustang III http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

(Not scientific test of course, just me messing about in QMB.) </div></BLOCKQUOTE>
Thats odd...his top speed is going to be so much lower that it'll look like he's standing still. </div></BLOCKQUOTE>

yep, perhaps it just lacks acceloration (up high) or something like that

it wasnt a test by anymeans, if u wanted we could run some side by side tests http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Viper2005_
01-29-2006, 03:16 PM
I think that further investigation is worth while.

I shall therefore investigate the P-51B, the P-51C and the Mustang III in game to obtain a side by side comparison of their performance, which hopefully will allow the effect of the engine to be isolated.

<span class="ev_code_RED">P-51B</span>

Maximum speed at sea level: 587 km/h (365 mph)

FTH in MS gear ~ 14,500 feet with ram.
Maximum speed at MS FTH: 670 km/h (416 mph) radiator set to AUTO, 695 km/h (432 mph) radiator closed.

S/C gearchange altitude ~ 19,400 feet in the climb at maximum power.

FTH in FS gear ~ 25,000 feet with ram.
Maximum speed at FS FTH: 685 km/h (425 mph) radiator set to AUTO, 728 km/h (452 mph) radiator closed.

At 30,000 feet top speed was 660 km/h (410 mph) with the radiator set to AUTO, at which point the engine was giving 54" Hg boost and 3100 rpm.

With the radiator closed a speed of 714 km/h (444 mph) was obtained, at which point the engine was giving 55" Hg boost and 3100 rpm.

This suggests that the P-51B in game is fitted with the V-1650-3 engine. Its performance appears to be fairly accurate, though two problems are apparrant.

i) as with most aircraft in game, cooling is a major problem. The radiator shutters should be almost fully closed at high altitude and overheating should not be a problem:

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

As such closing the radiator should make almost no difference at altitudes above about 15,000 feet and it should be possible to run flat out at high speed with the radiator shutters fully closed above this height without causing engine damage through overheating.

Radiator drag with the shutters (both water and oil) fully opened should cost about 34 mph IAS at 18,000 feet when the aeroplane is running flat out. This equates to around 45 mph TAS on a standard day. As such the radiator drag in game is somewhat optimistic, but the need to open the radiator in the first place is unrealistic and so the net result is that the P-51B, like most aeroplanes in the game, has its performance at altitude severely limited by the need to cool the engine.

ii) FTH in FS gear is around 3500 feet too low. It is as though the V-1650-3's FS gear has been replaced with that from the V-1650-7. To test this hypothesis I will conduct tests in the P-51D-5 (all P-51Ds were fitted with the V-1650-7).

<span class="ev_code_RED">P-51C</span>

Maximum speed at sea level: 562 km/h (349 mph) radiator AUTO, 593 km/h (368 mph) radiator closed.

MS FTH ~14,500 feet with ram (~13,700 at climb speed).

Maximum speed at MS FTH: 665 km/h (413 mph) radiator AUTO, 699 km/h (434 mph) radiator closed.

S/C gearchange altitude ~ 19,500 feet in the climb at maximum power. As this is dependent upon rate of climb and airspeed in the climb it is safe to assume that the S/C gearchange parameters are identical for the P-51B and the P-51C.

FS FTH ~24,500 feet (~24,000 ft in the climb).

Maximum speed at FS FTH 688 km/h (427 mph) radiator AUTO, 727 km/h (451 mph) radiator closed.

From this it seems reasonable to conclude that the P-51B and P-51C are identical within the limits of experimental error; the P-51C in game is also fitted with the V-1650-3 engine; the same issues apply.

<span class="ev_code_RED">P-51D-5</span>

Maximum speed at sea level: 574 km/h (356 mph) radiator auto, 605 km/h (375 mph) radiator closed. Acceleration noticably faster, as it should be given the extra power supplied by the V-1650-7 at low altitude.

FTH in MS gear was 9,500 feet in the climb, 10,500 feet with ram.

Maximum speed at MS FTH 645 km/h (401 mph) radiator AUTO, 684 km/h (425 mph) radiator closed.

S/C gearchange height ~17,000 ft in the climb.

<span class="ev_code_GREEN">This would appear to confirm that the Mustang III in game is correctly fitted with a V-1650-7 which has incorrectly been given 81" Hg performance with 71" Hg manifold pressure, as the Mustang III shows a slightly (but insufficiently) lower FTH and supercharger gear change than the P-51D-5.</span>

FTH in FS gear was 24,500 ft with ram

<span class="ev_code_YELLOW">This would appear to confirm that the V-1650-3 and -7 in game have the same FTH in FS gear which is another error, costing the P-51B and C high altitude performance without the increased low altitude performance made available by the -7 engine's lower MS gear. I shall next test the Spitfire to see if this problem covers Rolls-Royce Merlins in game as well as Packard Merlins.</span>

<span class="ev_code_RED">It is worth pointing out that the P-51B & C hit their published maximum speed in FS gear despite the altitude reduction associated with the FS gear error, and as such most likely have too little drag.</span>

At this point my P-51D suffered engine failure. Seems like a good time to post my findings...

*Heck that took a lot of editing!*

Buzzsaw-
01-29-2006, 05:16 PM
Salute Viper

While you're investigating the P-51's, maybe you would like to do an investigation of the stall characteristics, instability and wing loss issues.

If you put the same degree of research into those, you might discover the P-51's are completely mismodelled in regards to wing loss, stall and stability, and that the FM as portraying in IL-2 does not bear any resemblance to the actual aircraft.

Personally, I'd be happy to trade some speed for an aircraft which actually flies with some stability, can be aimed, and does not stall on a razor's edge.

Viper2005_
01-29-2006, 05:24 PM
Such things are unfortunately rather harder to test...

Buzzsaw-
01-29-2006, 05:28 PM
Salute Viper

Good copout. Any excuse to continue the usual bashing of any inaccuracies which favour allied aircraft, while ignoring those which cripple them.

Brain32
01-29-2006, 05:44 PM
Well what issues? I encounter and meet many P51 pilots who actually know what they are doing, but they don't come here and whine. Maybe you guys should stop with the merry go around circling fights?

Buzzsaw-
01-29-2006, 05:46 PM
Salute

No one flys the P-51's online anymore.

The syncronized .50 cals are pathetically ineffective, they can't be aimed because of the aircraft's instability issues, the aircraft stalls instantly without warning on any kind of hard maneuvering, the wings rip off at speeds which the P-51 was cleared by the USAAF to maneuver at, and the fuselage tank instability is a constant with no way to empty the 85 gal behind the seat tank first as was done historically.

And Viper is in an uproar about the top speed... http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Viper2005_
01-29-2006, 06:06 PM
If you were to take the time to read what I have written you will notice that I have pointed out areas where the P-51 is underperforming as well as overperforming in the game.

The objective of this thread is to highlight a quantifiable performance problem, because it so happens that I can do that with the tools available to me.

I cannot measure stick force per g in game since I have no way of measuring the stick forces applied by my virtual pilot.

Little purpose would be served by measuring long and short period oscillations since I don't have any data with which to compare the results this time consuming process would generate.

If you are better able than me to do such things then perhaps you would care to post some test data taken from the game, and some real life data with which to compare it. Otherwise kindly take your whine else where.

<span class="ev_code_RED">This thread is sober.</span>

Brain32
01-29-2006, 06:08 PM
=S=
Lets go now:

No one flys the P-51's online anymore.
Not true and Viper and I know that very well because we are hooked up on the same server quite often, today the sky was full of P51's and P47's and they owned the sky flying smart and using their planes advantages, we were caught pants down.
So what are the real problems here? Instability? Yes it's definitely a problem, .50 cals? Yes they are a bit funky,but I think your main problems are your cannon equiped friends(HINT:Kill steal) because after only one well placed .50 burst smart fw/me pilot will be RTB
Wing break, I never expirienced this with reasnoble manouvering even at extreme speeds and I'm not the only one http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif That annoying high speed snap stall? Been there, done that but was my fault actually, it happened o me only once.
What P51 pilots really need are only 2 things:
Fix of the wobble problem, and .50 desync(if that will help aiming).

Buzzsaw-
01-29-2006, 06:29 PM
Salute

Much data has already been posted on this board outlining in detail the G limits of the P-51, the various USAAF memos regarding the fuselage tank, charts on the performance characteristics of the U.S. M2 .50 cal weapon, as well as stall characteristics, and stall speeds of the aircraft.

If Viper is really interested in presenting a balanced view of the current Game P-51 FM, then he would illuminate those issues as well, instead of focusing solely on those aspects of the P-51's FM which are overmodelled.

And when someone actually has the temerity to point out this ommission, we get the usual ****ging from other Blue fanboys telling us how wonderful an aircraft the P-51 is, and how we just need to learn how to fly it. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Tator_Totts
01-29-2006, 06:33 PM
Originally posted by Brain32:
=S=
Lets go now:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> No one flys the P-51's online anymore.
Not true and Viper and I know that very well because we are hooked up on the same server quite often, today the sky was full of P51's and P47's and they owned the sky flying smart and using their planes advantages, we were caught pants down.
So what are the real problems here? Instability? Yes it's definitely a problem, .50 cals? Yes they are a bit funky,but I think your main problems are your cannon equiped friends(HINT:Kill steal) because after only one well placed .50 burst smart fw/me pilot will be RTB
Wing break, I never expirienced this with reasnoble manouvering even at extreme speeds and I'm not the only one http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif That annoying high speed snap stall? Been there, done that but was my fault actually, it happened o me only once.
What P51 pilots really need are only 2 things:
Fix of the wobble problem, and .50 desync(if that will help aiming). </div></BLOCKQUOTE>

I agree just one more thing the stall seems wrong. I have not flown much since this patch came out but if I remember try doing a medium speed nose up yoyo turn to the right. And you do not need full deflection and see what happens. I will have to dust off my joystick to give you more exact figures.

Buzzsaw-
01-29-2006, 06:59 PM
Salute

Just as a sample, here is a page from the Mustang manual, detailing the stall characteristics.

http://img76.imageshack.us/img76/3283/must145jm.jpg

Note that it states:

"...when no fuel is carried in the fuselage tank, slight tail buffeting occurs about 3 - 4 mph above the stall, at which the right wing drops GENTLY..."

The current Mustang FM has ALL stalls modelled on an aircraft with the fuselage tank full, something which was emphatically counteracted by orders that pilots were to burn the fuselage tank first, before even the drop tanks.

High speed stall is noted as:

"...If the aircraft is stalled in a steep turn, either wing will drop very rapidly. THE STALL IS PRECEDED BY PRONOUNCED JUDDERING. Recovery is IMMEDIATE if the pressure on the control column is released."

High speed stall in the game is preceded by no warning, and recovery is very difficult.

This type of information has been posted on this board many times before.

Viper2005_
01-29-2006, 07:09 PM
Can we please try to stay on topic ladies and gentlemen?

This thread is about the level flight performance of the Mustang III and the performance of its engine, the V-1650-7 with respect to speed and altitude.

Surprisingly enough this means that posts relating to such subjects as the stability of the P-51, the Browning M2's effectiveness or otherwise, the stalling behaviour of the P-51, the structural performance of the P-51's wings or indeed for that matter pretty much anything else are <span class="ev_code_RED">OFF TOPIC</span>.

Therefore, if you want to discuss them you should start your own thread for the purpose. Feel free to PM me if you would like my input, but <span class="ev_code_RED">please keep this thread on topic. </span>

Buzzsaw-
01-29-2006, 07:38 PM
Salute Viper

Thanks for acknowledging that you don't want to discuss the multiple issues which are crippling the performance of the P-51's, but would rather just talk about the one issue which lends it a slight advantage.

geetarman
01-29-2006, 07:40 PM
Originally posted by Viper2005_:
Can we please try to stay on topic ladies and gentlemen?

This thread is about the level flight performance of the Mustang III and the performance of its engine, the V-1650-7 with respect to speed and altitude.

Surprisingly enough this means that posts relating to such subjects as the stability of the P-51, the Browning M2's effectiveness or otherwise, the stalling behaviour of the P-51, the structural performance of the P-51's wings or indeed for that matter pretty much anything else are <span class="ev_code_RED">OFF TOPIC</span>.

Therefore, if you want to discuss them you should start your own thread for the purpose. Feel free to PM me if you would like my input, but <span class="ev_code_RED">please keep this thread on topic. </span>

As a Mustang lover, I appreciate your efforts. Appears we have a too fast MkIII, a B and C that don't do as well as they should up high, and a D that doesn't do as well as it should at lower alts. Is the opposite also true then?

Viper2005_
01-29-2006, 08:42 PM
Geetarman, as far as I can tell, the D is the only Mustang which has reasonably accurate engine performance with regard to full throttle heights (FTH in MS gear is about 1000 feet too low; FTH in FS gear is bang on the money).

However, I didn't complete level speed runs in FS gear with the P-51D-5, and carried out no testing whatever of the P-51D-20 so I cannot claim to have collected a complete set of data by any means.

In MS gear the performance data I have collected brackets the numbers published by North American in Report No. NA-46-130, which may be found here:

http://www.spitfireperformance.com/mustang/mustangtest.html
(scroll down)

I can carry out testing in FS gear if you would like, but as it does not relate directly to the question of the Mustang III's performance I would rather place the results of any such testing in another thread.

The problem with this flight testing business is that I don't have access to precise information about the aircraft I'm testing in game. Considerable detective work was required to even work out which engine the P-51B and C are modelled with, as for weight and balance, your guess is as good as mine!

More data with regards to modelling assumptions would make testing much easier!

lbhskier37
01-29-2006, 09:45 PM
Wow did anyone see what just happened in this thread? Kurfust came in and pointed out a game flaw that is hurting the P51 (bombrack drag)! This is historic!

But same old Buzzsaw coming in and crapping on a usefull thread. I guess any thread about the P51 that isn't claiming it is completely unflyable is luftwhining http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Buzzsaw did you close your eyes and skim over the parts where Viper is claiming the B and C are too slow at altitude? Seems like someone else is sinking down to be taken about as seriously as Hayateace.

fordfan25
01-29-2006, 10:17 PM
Originally posted by robban75:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brain32:
Robban made the tests:

I'd just like to add that I have always made tests with wind and turbulence on. For speeds without wind, detract 6-8km/h from the top speed.

The speed test below is made without wind and turbulence.

Crimea, full fuel default loadout, rads closed. In meters and km/h(TAS).

Mustang III

SL - 650
1K - 675
2K - 705
3K - 730
4K - 730
5K - 720
6K - 760
7K - 771

The Mustang III, as well as P-51B/C/D, lose between 40 and 60(!) km/h in top speed with wing racks fitted! http://forums.ubi.com/images/smilies/blink.gif </div></BLOCKQUOTE>

why with out wind and turbulence. those are not missing when thay tested the real fighters IRL?

Buzzsaw-
01-29-2006, 11:26 PM
Originally posted by lbhskier37:
But same old Buzzsaw coming in and crapping on a usefull thread. I guess any thread about the P51 that isn't claiming it is completely unflyable is luftwhining http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Buzzsaw did you close your eyes and skim over the parts where Viper is claiming the B and C are too slow at altitude? Seems like someone else is sinking down to be taken about as seriously as Hayateace.

Ibhskier you have never posted a single thing in your whole history on this board which is not biased and blue based.

I have had you **** all over legitimate threads of mine innumerable times. You and the rest of the 109 whiners have yet to explain the UFO like stall characteristics of that aircraft, the fact it suffers no torque effects, or that requires next to no adjustment to rudder trim whatever the speed.

This thread's title is 'MUSTANG III PERFORMANCE ISSUES', and that is the focus. Not the B or C.

This is the one aircraft which can legitimately outtrun most Axis aircraft, which SHOULD outtrun them, so of course, the attack is on it.

Blue fanboys are not satisfied with the poor stability, bad stall, wing loss and ****ty guns of this aircraft, so they have to attack the one thing which it may be overmodelled in, that being speed. (and I am not so sure the speed results given are accurate, I don't get anywhere near those figures)

Viper2005_
01-29-2006, 11:45 PM
Look at the track if you doubt the speed obtained.

http://www.war-clouds.com/forums/viewtopic.php?t=402

Hristo_
01-29-2006, 11:50 PM
Knowing Viper, he most likely double checked before posting. I'd take his word before anyone else's in this thread (no disrespect intended).

So, if his tests and backup data claim that MkIII is off in one aspect of its performance, better come up with proof that it isn't. Personal attacks and clouding the issue with gameplay concessions won't cut it.

Von_Rat
01-30-2006, 01:26 AM
Originally posted by Buzzsaw-:
Salute Viper

Thanks for acknowledging that you don't want to discuss the multiple issues which are crippling the performance of the P-51's, but would rather just talk about the one issue which lends it a slight advantage.


buzzaw if you got proof about other p51 issues send them to oleg, i too think like you, that p51 suffers badly from inaccurate modeling.

if you don't have any proof then shutup. viper is not under any obligations to prove your right.

robban75
01-30-2006, 01:38 AM
Originally posted by fordfan25:
why with out wind and turbulence. those are not missing when thay tested the real fighters IRL?

Only ground speed is affected by wind, IAS and TAS is unaffected in reality. But for some strange reason wind adds speed in-game. Every plane is 6-8km/h faster with wind, which makes true airspeed more like ground speed.http://forums.ubi.com/images/smilies/blink.gif

With wind I can reach close to 780km/h with the Mustang III.

Buzzsaw-
01-30-2006, 08:21 AM
Salute

More of the usual bashing by Blue fanboys who don't want to acknowledge the hypocrisy of their stance.

If the posters were really interesting in obtaining an accurate Flight model for the Mustang's, they'd look at all the issues relating to this aircraft, instead of focusing on the one which shows an advantage.

The reason they don't is simply that they are not interested in accuracy, they are just interested in gaining whatever advantage they can for the Blue side.

Any balanced assessment of the Mustang's performance would indicate that it is overall, drastically undermodelled, and handicapped by incorrectly set parameters. But rather than acknowledge that, and push for a complete overhaul of the way it flys, this group of blue cheerleaders prefers to leave the grossly mismodelled aspects that cripple it in place, while insisting that its too high speed be corrected to historical levels.

Meanwhile of course, they ignore all the other issues which bear on their own preferred aircraft, since an objective examination of those would result in a loss of those artificially created advantages.

p1ngu666
01-30-2006, 08:35 AM
*hands buzzsaw flameproof clothes*

lbhskier37
01-30-2006, 08:50 AM
Fix the frickin wobble and guns for all I care, just quit flaming Viper. Has anyone in here mentioned anything about the guns, wobble, and even wing shear being correct? Do you flame Tagert for doing climbrate tests for the P38 without mentioning the .50s?

And about MY 109 whining, I'd like to see you find a recent post of mine complaining anything about the 109. The only time I fly that plane is when I am in a coop with my squad that only includes 109s. Normally I will even go red and fly P38s or P47s before 109. Frankly I don't know what the issues with the 109 are becuase I don't fly it, if it is wrong than it should be fixed. I'm all for all aircraft to be as representative as they can be in this game. If you actually look at any of my "whines" in the recent past they have all been about getting more bombers and mid/early war planes in here instead of all these latewar stuff that flew when the war was already decided.

Viper ignore this **** and continue doing what you are doing. It would also be nice to see this FTH stuff done with the P47late and the G6-AS. I know for sure the G6-AS is messed up (too fast at low alt, too slow at high alt) P47late I'm not sure, maybe Oleg did the same thing. P47 late should get a big boost at low altitudes and above the critical alt should be the same as the P47D27. And just subjectively when I flew it, it doesn't seem to be the case.

Hetzer_II
01-30-2006, 10:28 AM
*hands buzzsaw flameproof clothes*

*kicking his nuts would be better... but i bet he would feel nothing...*

Viper2005_
01-30-2006, 11:29 AM
It's harder to do the P-47 because I don't know where to get the real life data from - ditto the Bf-109 and Fw-190. Is there a site like that provided by Mark Williams for other WWII combat aircraft? I could take some data from the curves he uses for aircraft comparisons, but without background information such curves can be very misleading. With Luftwaffe aircraft I'm afraid that my German isn't really good enough to get the subtleties out of test reports so I would have to rely upon translations.

If you post data then I'll test fly the game.

My next project for the Mustang III is likely to be weighing it.

This is easier said than done, but I think that I have developed a viable test procedure.

I shall glide test the aircraft to determine L/D max.

I shall then record the EAS at L/D max with a full fuel load.

Next I shall repeat the procedure with a 25% fuel load (or if I have the time, I'll run the tanks dry and test with 0% fuel).

Since the EAS at L/D max varies as the square root of the weight I can therefore work out the mass ratios between two different fuel loads.

As the mass of the fuel is known within pretty tight limits I can therefore work backwards to determine the mass of the aeroplane.

The procedure is valid for all of the aeroplanes in the planeset. It is likely to be rather time consuming, since lots of glides will be needed. As such, I suggest that those of you who are interested in different aeroplanes start gliding them.

Once the weight of the aeroplanes under test is known it will be possible to carry out far more useful experiments.

I think that there may also be a viable method for the determination of the CoG of most of the aeroplanes in the planeset via ground testing.

Briefly this approach would involve deliberately nosing over the tail draggers by hard braking and measuring the angle at which they fall forwards rather than backwards since at this point the CoG must be vertically above the contact point of the main gear.

Such an approach would be especially applicable to the Mustang since the aft tank should cause very large CoG changes with variations in fuel load.

This simple method would locate the CoG somewhere along a line which would cut through the fuselage. However to locate the CoG accurately, triangulation is required. As such, further tests will be needed, although I haven't yet worked out how best to carry out such tests.

In addition, this simple method will give the CoG gear down, which may be somewhat different from the CoG gear up. But at least it's a start.

lrrp22
01-30-2006, 01:14 PM
Mr. Mustang III checking in! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

First off- with radiators closed and no wing racks the Mustang III is definitely too fast at altitude. I discussed this with Robban earlier and we decided that the issue definitely needed to go to Oleg.

However, there are two issues which need to be looked at first€¦

First, as mentioned previously, wing racks reduce Mustang top speeds anywhere from 40 to 100 kph while the historical reduction was in the 12-22 kph range. IIRC, with wing racks fitted, the Mustang III€s top speeds are in the ballpark at higher altitudes, but way too slow at low altitudes. The P-51B/C/Ds are drastically too slow at all altitudes with racks fitted.

Second, all P-51s in-game are very drastically affected by radiator flap setting. With radiators set to auto, again, the B/C/D are way too slow while the Mustang III is still probably too fast at higher altitudes but again considerably too slow at lower altitudes. So- in order for the B/C/D to reach close to historical speeds, they have to be run with radiators set to 'closed'. Therein lies the problem- all of the published P-51 speeds were tested with radiator flaps set to 'Automatic'. During those tests, top speeds were reached with the larger radiator exit flap typically opened around 7.25 inches. Those tests indicate that the coolant and oil temperatures all remained normal through the entire test regime, even in combat power climbs, and even at higher boost levels. In-game, the B/C/D only reach top speeds with the radiators set to €˜Closed€ and quickly overheat once top speed is reached. The Mustang III is around 40 kph too slow at sea level with radiators set to €˜Auto€ and probably pretty close to the correct 710-715 kph at 7400 meters. With both wing racks fitted and radiators set to €˜Auto€ it looks like all the in-game Mustangs are drastically too slow compared to historical data.

So, basically, we have to pick our poison with regards to Mustang speed performance: either we accept drastically undermodeled speed performance while using historical radiator settings and/or wing racks, or we accept Mustang III speeds that are (way) too fast at high altitudes with radiators closed/no wing racks. As it stands now, the B/C/D *are* drastically undermodeled at all altitudes both with radiators set to the historical €˜Auto€ setting and with wing racks. The other side of the coin is a Mustang III that is considerably too slow at some altitudes with radiators set to €˜Auto€ and/or with wing racks, but highly overmodeled at some altitudes when in clean/radiators €˜Closed€ configuration.

I€m going to have to find some time to re-test the various configurations, but I€m pretty sure the above impressions will hold true. Then again, the new Beta might make this conversation irrelevant.

LRRP

robban75
01-30-2006, 01:32 PM
I say fix the wing rack bug. It's more important IMO. The B/C/D suffers the most from this. Mustang III pilot will have to promise to stay at low altitudes! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

lrrp22
01-30-2006, 02:42 PM
Originally posted by robban75:
I say fix the wing rack bug. It's more important IMO. The B/C/D suffers the most from this. Mustang III pilot will have to promise to stay at low altitudes! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Not gonna happen! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif Oleg made it perfectly clear that the current FM can only model one type of wing/bomb rack. Unfortuantely, that bomb rack is 3-5 times as draggy as the Real World P-51's was.


Frankly, at this point I don't know what to do with regards to the Mustang III. Here's what I'd like to see happen: knock 50-60 kph off its top speed at high altitudes; leave the low altitude speeds the same *But* give all Mustangs their top speeds with radiators partially open on the 'Auto' setting.

On a related note- with the K-4 going to 1.98 ata *and* having its manueverability increased?!, I really hope that the Mustang's wobbles and treacherous handling (and synched guns, and wing shear, and max dive speed... http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif ) are improved. Somehow I doubt it. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Viper2005_
01-30-2006, 03:01 PM
The problem is that the efficiency of the cooling system is chronically "undermodelled" in the game. This applies to almost all of the aeroplanes in the game.

As such aeroplanes with automatic radiators are at a quite dramatic disadvantage because operation at high power invariably results in fully opened radiators and red hot engines.

In the case of the P-51, the actual radiator drag seems if anything slightly optimistic. However, the fact is that the radiators shouldn't be open most of the time, and as a result the aeroplane underperforms with the radiators set to auto.

The P-51 slightly overperforms with the radiator closed; that's fair enough given that IRL with the radiator set to AUTO it would be perhaps an inch or so from the flush position during high power operations.

I think that the first step should be to get the engines right with regard to boost and FTHs.

Then the cooling bug should be stomped on. This would benefit all the aeroplanes in the game. The P-47D stands as proof that this is possible within the engine. It is pretty much alone amongst the aeroplanes modelled in the game in having reasonable overheating performance.

Once this is dealt with the bomb rack issue will fall into place; it will become glaringly obvious that they produce grossly excessive drag and hopefully this will then be corrected.

Maybe if there's a 4.04 patch...

Incidently I just found the P-47 performance reports on Williams' site. I will investigate http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

lbhskier37
01-30-2006, 03:04 PM
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 robban75:
I say fix the wing rack bug. It's more important IMO. The B/C/D suffers the most from this. Mustang III pilot will have to promise to stay at low altitudes! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Not gonna happen! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif Oleg made it perfectly clear that the current FM can only model one type of wing/bomb rack. Unfortuantely, that bomb rack is 3-5 times as draggy as the Real World P-51's was.


Frankly, at this point I don't know what to do with regards to the Mustang III. Here's what I'd like to see happen: knock 50-60 kph off its top speed at high altitudes; leave the low altitude speeds the same *But* give all Mustangs their top speeds with radiators partially open on the 'Auto' setting.

On a related note- with the K-4 going to 1.98 ata *and* having its manueverability increased?!, I really hope that the Mustang's wobbles and treacherous handling are improved. Somehow I doubt it. http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif </div></BLOCKQUOTE>

I would think the speed at alt thing could be an easy fix, all Oleg has to do is adjust the hp vs. alt curve. As for the speed with radiators, I think this is more of a global thing that needs to change. At altitude pretty much any plane should be able to fly full speed with radiators closed. I'm willing to bet that when Mustang speed tests were run in real life the radiator even on auto stayed closed, at least for speed tests at altitude. I think in PF the radiator and overheating are just a really big simplification of engine management and won't be improved until BoB. In reality I think "overheating" was less common than in this sim, and is just a replacement for all the other stuff that would go wrong with an engine that was mishandled. Since it currently is an issue that hampers pretty much all aircraft I think the overheat issue will be left alone until BoB. I'm looking forward to seeing what BoB brings to engine management and durability, maybe we will see overcooling, detonation from running too low RPM at high boost, overspeeding in dives, realistic 190 engine management, and realistic emergency systems (like in the 190 if its automatic system fails, and for US planes if the CSP fails).

lrrp22
01-30-2006, 03:18 PM
Viper,

I'm with you, mostly. I say 'mostly' because I don't think that P-51B/C/D speeds are at all optimistic with radiators closed. All the listed top speeds were achieved with radiators partially open while in-game those speeds can only be reached with radiators closed and right at the edge of overheat. Even then, 67" Hg speeds in clean configuration are at the lower end of service tests for the most part(for example, 710 vs 725 kph for the B/C). The exception of course being the Mustang III at high altitude, where it is way too fast- until you set the radiators to 'auto', then I think it is pretty close.

Viper2005_
01-30-2006, 03:50 PM
I'm getting ~ 450 mph from 67" Hg with the P-51B & C despite their FTHs being some 3,500 feet too low .

At 24,500 feet they should "only" be capable of about 438-440 mph.

Likewise, my 30,000 ft in the P-51B run gave the correct speed whilst drawing 5" Hg too little boost (due to the FTH bug).

It is a reasonable assumption IMO that at these altitudes the performance with the radiator closed is the same as that which should be obtained with the radiator set to AUTO.

Therefore there appear to be two possibilities:

i) the power curve has been tweaked to compensate for the FTH bug

ii) the drag curve has been tweaked to compensate for the FTH bug

Testing could be carried out to ascertain exactly what's going on, but at the moment the performance of the P-51B & C appears optimistic at 24,500 ft and 30,000 ft <span class="ev_code_red">in relation to the indicated horsepower supplied</span> (I have not tested the C at 30,000 ft but it is identical to the B within the limits of experimental error at all other heights, and it seems reasonable to assume that this relationship holds in the absense of concrete data).

The other area of optimism is the actual quantity of radiator drag with everything wide open, at least in relation to this report:

http://www.spitfireperformance.com/mustang/p51b-12093.html

I certainly would not seek to complain about this in the context of the current FM. But I would hope to see it fixed along with the other issues associated with the Mustang III.

Really the P-51D is a different animal and as such I think it should be discussed in another thread. Suffice it to say that I think the P-51D is more accurately modelled than the Mustang III at present with regard to FTHs, though I have not carried out high speed runs in FS gear, nor have I examined the P-51D-20.

As I'm sure you can imagine, I'm finding flight testing to be a somewhat time consuming process!

lrrp22
01-30-2006, 04:28 PM
Hi Viper,

I'm glad to hear you're getting 450 mph, albeit at the wrong altitude! Sounds like the MS and FS gear full throttle heights are a mix of V-1650-3 and -7 at this point.

What penalty are you getting for open radiators? IIRC, I get around 25 mph which matches the historical loss for the coolant radiator flap but is 9 mph short for both coolant and oil cooler flaps. However, I think it would be extremely difficult to get both to open fully during level flight in real life.


Originally posted by Viper2005_:
I'm getting ~ 450 mph from 67" Hg with the P-51B & C despite their FTHs being some 3,500 feet too low .

At 24,500 feet they should "only" be capable of about 438-440 mph.

Likewise, my 30,000 ft in the P-51B run gave the correct speed whilst drawing 5" Hg too little boost (due to the FTH bug).

It is a reasonable assumption IMO that at these altitudes the performance with the radiator closed is the same as that which should be obtained with the radiator set to AUTO.

Therefore there appear to be two possibilities:

i) the power curve has been tweaked to compensate for the FTH bug

ii) the drag curve has been tweaked to compensate for the FTH bug

Testing could be carried out to ascertain exactly what's going on, but at the moment the performance of the P-51B & C appears optimistic at 24,500 ft and 30,000 ft <span class="ev_code_red">in relation to the indicated horsepower supplied</span> (I have not tested the C at 30,000 ft but it is identical to the B within the limits of experimental error at all other heights, and it seems reasonable to assume that this relationship holds in the absense of concrete data).

The other area of optimism is the actual quantity of radiator drag with everything wide open, at least in relation to this report:

http://www.spitfireperformance.com/mustang/p51b-12093.html

I certainly would not seek to complain about this in the context of the current FM. But I would hope to see it fixed along with the other issues associated with the Mustang III.

Really the P-51D is a different animal and as such I think it should be discussed in another thread. Suffice it to say that I think the P-51D is more accurately modelled than the Mustang III at present with regard to FTHs, though I have not carried out high speed runs in FS gear, nor have I examined the P-51D-20.

As I'm sure you can imagine, I'm finding flight testing to be a somewhat time consuming process!

Viper2005_
01-30-2006, 04:52 PM
RE FTHs, that's exactly my view (I think I posted to that effect on page 2 - yellow text).

The V-1650-3 at present has the same FS gear as the -7 which almost completely defeats the object of the -3.

I get about 25 mph radiator drag, and I think that we should be be getting rather more than that. Remember that the 34 mph thing was at 18,000 feet so you need to do a TAS conversion. It comes out to about 45 mph if memory serves; the higher you go the bigger the effect is likely to be, though this only matters in the game as the radiator should be shut at high altitude.

Personally I think that the radiator drag error is a good thing given the radiator suitability error (to use period terminology).

However, I hope to see it fixed in the longer term.

The overall performance of the Mustang III at 67" Hg is pretty close to the book figures if you fly clean and shut the radiator. It has some engine issues in slow flight (I can't obtain less than 30" Hg at sea level, and I can't maintain 2700 rpm to sufficiently low boost, so that I can't fly the correct landing profile, although much to my surprise it will climb with everything hanging in the breeze at 46" Hg, even with full fuel, just as the book says!).

As for bomb rack drag, it has always struck me as excessive on almost every aeroplane. Interestingly the Fw-190A8 and A9 have no performance penalty that I can detect for their bomb rack; as far as I can tell they are unique in this respect.

lrrp22
01-30-2006, 05:03 PM
Ah, I completley missed the IAS qualifier. Wow, I wonder what kind of penalty the 109's four wing radiator flaps and single oil cooler flap incurred?

A question: what throttle setting are you using to reach 67" Hg with the Mustang III? All I can get is 61" at 100% with an immediate jump to 70" (why 70"?) on the MAP guage from 101-110%. We should be able to set the throttle at any increment from 61" to 75" Hg but the gauge just doesn't work right currently.

Oleg was reluctant to model an RAF +25 lbs boost gauge in the mk III since we didn't have any proof that the U.S. gauge was replaced, but I've since found a photo of a 19 Sqn Mustang III with a +25 lbs gauge. It's probably too late to get the cockpit model modified, but I think I'll send the request to Oleg anyway!

LRRP

Viper2005_
01-30-2006, 05:29 PM
I've already gone through most of this in the thread already.

If you'll look closely you'll see the flat out the Mustang III gives between 70" Hg and 71" Hg. It should give between 80" Hg and 81" Hg since that would be 25 psi.

I can't get 67" Hg out of it at all. In the WEP range I find that moving the throttle modulates rpm.

However this doesn't matter since actually the Mustang III is just a P-51B/C in RAF service. It so happens that we've got one fitted with a V-1650-7 rated to +25 psi, but actually a substantial proportion of the RAF's Mustang IIIs were fitted with the V-1650-3 just like the P-51B & C in game.

For this reason I have used them as the basis of comparison, throwing up the V-1650-3 FTH bug as a result.

As for the 109, I suspect that the impact of open radiators would be no greater than for a Mustang because its baseline drag (especially cooling drag) is rather larger.

"On Design" the Mustang is very good with regards to cooling drag and as a result the contrast associated with going "off design" is all the more impressive.

lrrp22
01-30-2006, 06:21 PM
Yeah, I'm quite aware of what the Mustang III was in RL and what it does in-game. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif I was just wondering how you know that the Mustang III in-game is accurate at 67" Hg since there is currently no way to set the throttle to 67". I've tested it at 61" at SL and it is very close. I haven't quite figured out why we get 70" on the MAP gauge as oppossed to pegging at 75" Hg as it should.

Viper2005_
01-30-2006, 08:34 PM
Well, I don't.

I know that the P-51C is reasonably accurate at 67" Hg (in MS gear; the FS gear bug is another issue entirely).

As such it seems reasonable to assume that the Mustang III is accurate @ 67" Hg in MS gear since they should be the same aeroplane.

AFAIK the Mustang III has the same aerodynamics as the P-51C in game, and as such their performance should be equal at any given boost pressure. I haven't tested this, but experience suggests that at the very worst it isn't too far out.

lrrp22
01-30-2006, 08:48 PM
Viper,

The in-game P-51C features the V-1650-3 engine (P-51C-1-NT while the Mustang III has the -7 (P-51C-5-NT), so speeds should very 10-20 mph at most altitudes. At equal power settings the Mustang III should be within 1-3 mph of the P-51D at all altitudes. IIRC, it is.

Time for some more testing!

Viper2005_
01-30-2006, 09:05 PM
Yes I realise that. Had you read my earlier posts on page 2 you would realise that I have covered this ground. My point is that their aerodynamics should be identical.

As such, if the one is accurate at 67" Hg then so should the other, bearing in mind that that the V-1650-7 appears to give roughly the correct power in MS gear based upon testing of the P-51D-5.

This of course rests upon the assumption that the V-1650-3 gives the correct power in MS gear.

At present a large number of assumptions are required to hold my test data together. When I have the time I shall carry out further testing to nail down as many of those assumptions as possible.

However, please be advised that I have a degree to work on, and therefore progress may not be as fast as you might wish.

In the meantime I suggest you re-read the earlier parts of this thread in which I set out the details of my investigation in order that the need for further repetition is avoided.

lrrp22
01-31-2006, 01:15 AM
My latest Mustang III test results:

Mustang III
110% throttle, 100% fuel
Radiators set to 'Auto' (historical test setting)

SL--------615 kph
5,000 ft--651 kph
10,000 ft-692 kph
24,500 ft-716 kph

Those speeds match speeds for historical test conditions quite closely except at SL and 5k ft were they are around 30-40 kph too slow, and 10,000 ft which is 10-15 kph too fast.

Test at +25 lbs boost FS gear FTH of 16-17,000 ft next.

LRRP

Viper2005_
01-31-2006, 04:54 AM
Testing with the AUTO setting unfortunately serves to hide the performance of the aeroplane behind the universal cooling bug which blights almost ever aeroplane in the game. It especially punishes those with automatic radiators, since as a result of insufficient radiator suitability, after a short period of high power operation the AUTO setting results in fully opened radiator shutters and a massive drag penalty.

For this reason it seems more sensible to use a manual radiator setting to approximate the radiator position that the AUTO setting should provide, until the cooling bug is fixed.

I have conducted all of my testing with the radiator closed; perhaps I should conduct sea level runs with the radiator slightly open...

BigKahuna_GS
01-31-2006, 10:08 AM
S!
_______________________________________________
i didnt know it was too good up high
770 kph = 478.455818 mph
_______________________________________________



Maybe Oleg is making up for the P47M and the 72"MAP P51D Mustang on grade 150 fuel he left out of the sim. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

By the way Viper the P47D on 150 grade fuel is 10-15mph too slow depending on various altitudes.


http://www.spitfireperformance.com/p-47/p47-26167.html
Flight Test Engineering Branch
Memo Report No. Eng-47-1774-A
15 July 1944

FLIGHT TESTS ON THE REPUBLIC
P-47D AIRPLANE, AAF NO. 42-26167
USING 44-1 FUEL
I Introduction

Flight test have been conducted at Wright Field on the P-47D airplane, AAF NO. 42-26167, at the request of the Power Plant Laboratory, Engineering Division. These tests were made to determine the increased performance of the airplane using the higher powers allowable by use 44-1 fuel as compared with powers allowable with the standard fuel, grade 100/130, Spec. No. AN-F-28. From 15 April to 30 June 1944 approximately 30 hours were flown by Captain R. B. Johnston.

The P-47D is a single engine, high altitude figher. It is equipped with a Pratt & Whitney R-2800-63 engine furnished with a water injection system and a four-bladed Curtiss Electric controllable propeller, blad design No. 836-2C2-18.

II Summary

Preliminary tests were run to clear the airplane for performance with higher powers with and without water injection. Detonation equipment was installed to determine if any flight condition became marginal as to detonation, cooling or improper operation of auxiliary parts. No detonation was observed in level flight up to 65.0" Hg. without water and 70.0" with water. No detonation was observed in climb up to 65" Hg. without water. Detonation occurred at 65.0" with water in climb but was remedied by using a No. 18 water jet. Cylinder head and carburetor air temperatures remained below the limits in level flight. Excessive cylinder head and carburetor air temperatures were encountered in climbs, limiting the duration of any climb to a point where limits are reached.

The airplane and engine handled well at all altitudes at the higher powers. At 70.0" Hg., water injection, a maximum speed of 444 MPH was obtained at 23,200 feet. At 65.0" Hg., with water a high speed of 439 MPH at 25,200 feet and a maximum rate of climb of 3260 ft/min. at 10,000 feet were obtained. At 65.0" Hg., without water a high speed of 430 MPH at 25,400 feet and a maximum rate of climb of 2850 ft/min. at 12,000 feet were obtained. At 56.0" Hg. without water a high speed of 418 MPH at 29,600 feet and a maximum rate of climb of 2330 ft/min. at 12,000 feet were obtained. At 52.0" Hg. without water a high speed of 412 MPH at 31,400 feet and a maximum rate of climb of 2030 ft/min. at 12,000 feet were obtained.

III Condition of Aircraft Relative to Tests

A. Flight tests were conducted at a take-off gross weight of 13,230 lbs. with the c.g. at 29.9 MAC, wheels up. This weight corresponds to the full combat weight of the airplane aand includes full internal fuel, 15 gallons of water and ballast for 300 rounds of ammunition per gun.

B. All tests were conducted with landing gear retracted and wing flaps neutral. In level flight the cowl flaps were closed and the oil and intercooler flaps neutral; in climb cowl flaps, oil intercooler flaps were wide open. Gun blast tubes and wing racks were installed and all antennae were in place.

C. The airplane was finished with standard, service camouflage finish.

IV Flight Characteristics

A. Taxiing and Ground Handling

This airplane is easy to taxi and handles well on the ground as compared to other fighter planes with conventional landing gear. The brakes are touchy for the first one or two times used but after this they are smooth and respnd well without excessive pressure. The tail wheel is full swivel when unlocked and responds very easily. There is a handle on the right side of the cockpit to lock and unlock the tail wheel., When in the "lock" position the wheel locks when returned to the center for taxiing straight and for take-offs and landings. At times it is hard to unlock the tail wheel after landing but it unlocks if the cable leading back from the handle is "flipped".

Crosswind has very little effect on taxiing and ground handling. The tail wheel reacts well and the airplane handles sell in rough ground landings.

B. Take-off

Handling for take-off is good. WIth tail wheel in "lock" position, the airplane rolls straight and torque is very easily corrected for by using rudder and a few degrees right rudder trim. Aileron and elevator trim tabs are set in the neutral psoition for take-off. At lower power settings the take-off roll is very long but is greatly decreased by high power. Take-offs were not measured but they seem very short with War Emergency power and improve the pilot's confidence in the airplane. After the airplane is airborne, only a small change in rudder and elevator trim tabs is required to maintain climb.

All take-offs were made without flaps.

C. Stability

When trimmed in level flight for rated or normal power, the airplane is statically and dynamically stable directionally and longitudinally. Laterally, it has neutral stability. Also, when trimmed for 180 MPH glide, the stability is the same as with power.

D. Trim and Balance

Trim is easily maintained by using the aileron, elevator and rudder trim tab controls which are conveniently located on the left side of the cockpit. The trim tab controls work easily and are very sensitive. It takes considerable practive to trim the airplane and keep it trimmed because as on trim control is changed it requires changing others. At all altitudes and speeds the airplane can be trimmed to fly hands off. The auxiliary fuselage tank causes little extra trim when the gasoline from it is used first. If it is not used firstm the airplane becomes slightly tail heavy. When opening shutters or putting down wheels and flaps, a medium amount of trim is needed.

E. Controllability

Control can be maintained in all attitudes and speeds up to the diving limits. Changes in speed require change in trim and if trim is not made or controls held, the airplane yaws violenly. Thus, it requires quite a bit of practice for the pilot to maintain perfect control. For this reason, this airplane is not good on instruments. When the airplane gets out of trim it is very hard to retrim it on instruments.

F. Maneuvrability

No acrobatics were tried but rolling into turns and changing directions is very easily accomplished because of very light aileron forces. Rudder and elevator have somewhat heavier forces but not objectionably so. The radius of turn is large and the stick forces become very heavy in a turn requiring both hands on the stick.

The water control switch is objectionable because it must be held "on" by the pilot. This occupies the pilot's left hand and he cannot trim the plane or use both hands on the stick which is necessary to make a tight turn.

G. Stalling Characteristics

There is sufficient warning to the pilot of a stall. Slight buffeting of elevators can be felt in the stick, especially with cowl flaps open. Landing is not recommended with cowl flaps open because f false warning of stall and buffeting of elevator. Another warning of a stall is a jerking of the stick to the left. It will snatch the stick from the pilot's hand if he is holding it lossely. The stall is normal and the nose falls straight forward and normal recovery is easy.

H. Spinning Characteristics

No spins were attempted.

I. Diving Characteristics

Acceleration in a dive is fast with control forces building up and becoming high above 350 MPH indicated. There is little vibration except as the speed approaches compressibility. A normal amount of trim is required but the forces on stick and rudder could be held by the pilot. However, the trim tab controls are easily accessible and the airplane can be trimmed easily for a dive.

In a pull out from a trimmed eive of approximately 450 MPH indicated the stick forces increase with the number of "g's" applied during pull out. At apporximately 5 "g's" the forces are very heavy. There is no tendency toward stick reversals.

J. Operation on reduced Number of Engines

Not applicable

K. High Altitude Trials

Several flights were made over 30,000 ft. and no objectionable characteristics were noticed. The airplane performs and handles very similar to the way it does at lower altitudes. Sufficient heat from the engine and heater keep the pilot comfortable.

L. Approaches and Landings

There is good visibility to the sides and front for approaches though the nose partially blocks view ahead and below. Three point landings are very easily made in this airplane with full flaps and elevator trim well back. It will flare out nicely or can be forced on the ground by pulling the stick back abruptly and it will stay on the ground. Ground roll is straight wth very little tendecny for the nose to swing. Brakes can be applied with safety either to stop the roll or the keep the roll straight though the rudder is effective down to a very slow speed. Ground roll is fairly long though brakes can be safely used and greatly shortens this distance.

M. Night Flying

No night flying was done

N. Noise and Vibration Level tests at Crew Stations

Not applicable

O. Pilot's Report on Vision and Cockpit Layout

Vision is generally good from the cockpit. In level flight vision over the nose is good though this decreases with speed. For take-off with cowl flaps open and tail down the pilot can only see out the sides. The canopy is clear and there is no distortion. The struts are placed so that the pilot can look around them as necessary. The only blind spot is a cone af about 15? around the tail. A rear view mirror is installed but is very little help.

Cockpit layout is very good with conventional controls in convenient places and plenty of room for the pilot's comfort. There are no projections which catch clothing. Adjustable seat, rudder pedals, safety belt and harness can be easilty adjusted on the ground or in the air. The cockpit is easily accessable with sliding canopy and sufficient hand holds and steps for the pilot. The emergency exit is satisfactory with a handle that releases the canopy which slides back out of the way. Also, the panels on each side can be released in case of nosing over on its back.

The instruments are very well grouped and are easy to see with the flight instruments in the center and engine instruments grouped around them. The electrical panel is on the lower left side of the cockpit and is easily accessable.

P. Crew Report on Layout of Indivdual Stations

Not applicable

V Performance Data

A. Airspeed Calibration

1. The location of the airspeed position correction are given in Fig. 1.

B. Speed in Level Flight

1. The maximum speed at 2700 RPM. 70.0" Hg. (water injection) was 444 MPH at 23,200 ft.

2. At 65.0" Hg., 2700 RPM, water injection, a high speed of 439 MPH was obtained at 25,200 ft. With the water off at 65.0" Hg., 2700 RPM, 430 MPH was obtained at 25,400 feet.

3. The high speed at 56.0" Hg., 2700 RPM, was 418 MPH at 29,600 feet. The high speed at 52.0" Hg., 2700 RPM was 412 MPH at 31,900 feet.

4. Curves of Speed vs Altitude are given in Fig. 2 for a take-off gross weight of 13,230 lbs.

5. Power data for level flight is given in Fig 3, 4, 5.

C. Climbs

1. The service ceiling for 2700 RPM was 38,000 feet. The maximum rate of climb for 2700 RPM, 65.0" Hg., water injection was 3260 ft/min. at 10,000 feet. Without water at 65.0" Hg. the maximum rate of climb was 420 ft/min. less.

2. The rate of climb at 56.0" Hg., 2700 RPM, was 2330 ft/min. at 12,000 ft. and at 52.0" Hg., 2700 RPM, 2030 ft/min. at 12,000 ft.

3. Results of climbs made at take-off gross weight of 13,230 lbs. are given in Fig. 6 and Fig. 7.

4. Power data for climb is given in Fig. 8, 9, 10.

D. Stalling Speeds

Stalling speeds are given in the following table.


Wing
Flaps Landing
Gear Shutters Power IAS
MPH*
Up Up Closed Idling 116
Up Up Open Idling 116
Up Down Closed Idling 114
1/4 Down Closed Idling 109
1/2 Down Closed Idling 105
3/4 Down Closed Idling 101
Full Down Closed Idling 98
Up Down Closed Idling 114
Up Down Open 35" Hg. 2200 RPM 107
Up Up Open 45" Hg. 2550 RPM 103
Up Up Open 35" Hg. 2200 RPM 106
Up Down Open 45" Hg. 2550 RPM 104
Up Down Open 35" Hg. 2200 RPM 107

*This speed is the ship's uncorrected indicator speed, and is effected by attitude of airplane and balance of airspeed lines.

VI Curves

All data given in the following curves has been reduced to NACA Standard Atmospheric Conditions.

Speed in Level Flight
Rate of Climb & Ceiling
Time to Climb

VII Conclusions

A. The R-2800-63 can be operated at 65.0" Hg., 2700 RPM, in level flight and climb without water injection when using 44-1 fuel. It can be operated at 70.0" Hg., 2700 RPM with water injection with 44-1 fuel. Climbs at high power must be limited because of high cylinder head temperatures and carburetor air temperatures. Short climbs can be made without dificulty.

B. A gain of 19 MPH can be realized by using 65.0" Hg., 2700 RPM over 56" Hg., 2700 RPM. 8 MPH can be gained at 65.0" Hg. by using water injection. With water injection at 70.0" Hg., 2700 RPM, 7 MPH can be gained over 65.0" Hg., 2700, water injection.

C. In climb operation a gain of 510 ft/min. by using 65.0" Hg., 2700 RPM over 56.0" Hg., 2700 RPM can be realized. 410 ft/min can be gained at 65.0" Hg., 2700 RPM using wate injection. No 70.0" Hg. climbs were made.

VIII Recommendations

1. It is recommended the Pratt & Whitney R-2800-63 engines be rated at 65.0" Hg. with and without water injection when using 44-1 fuel or its equivalent.

2. It is recommended that the use of 70.0" Hg. be further investigated.

3. It is recommended that pilots using these higher powers be cautioned concerning the high cylinder head temperatures and carburetor air temperatures which may be encountered in extended climbs or level flight.


Main P-47 Performance Trials


http://www.spitfireperformance.com/p-47/p47d-44-1-level.jpg


http://www.spitfireperformance.com/p-47/p47d-44-1-level.jpg

Viper2005_
01-31-2006, 10:49 AM
http://forums.ubi.com/images/smilies/353.gif http://forums.ubi.com/images/smilies/1241.gif

If you want to talk about the P-47 then I suggest you start a thread about it. Please do not spam my thread with data relating to the wrong aeroplane (which is easily available anyway from Mark William's site; in such cases a link would suffice).

This thread is intended to relate specifically to the Mustang III.

I am quite happy to test other aeroplanes and discuss the results, but THIS IS NOT THE PLACE.

BigKahuna_GS
01-31-2006, 11:17 AM
S!


____________________________________________
Viper2005_ Posted Mon January 30 2006 10:29
It's harder to do the P-47 because I don't know where to get the real life data from - ditto the Bf-109 and Fw-190. Is there a site like that provided by Mark Williams for other WWII combat aircraft?
_______________________________________________


______________________________________________
Ibhusker--It would also be nice to see this FTH stuff done with the P47late and the G6-AS. I know for sure the G6-AS is messed up (too fast at low alt, too slow at high alt) P47late I'm not sure, maybe Oleg did the same thing. P47 late should get a big boost at low altitudes
and above the critical alt should be the same as the P47D27.
_______________________________________________



Hmmm Excuse me but I think you and Husker brought up the P47. I simply just provided the links and info so chill out on the spamming ok ?


This thread will stay on course just fine provided there isn't over reactions.
_

Viper2005_
01-31-2006, 11:58 AM
Incidently I just found the P-47 performance reports on Williams' site. I will investigate http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

I dislike quoting myself, but the above was taken from the bottom of Page 3. In other words, old news.

As I am sure you have noticed, this thread has suffered a lot of distractions. As such I am actively trying to nip all O/T discussion in the bud in order to keep this monster on track as best I can.

JG5_UnKle
02-01-2006, 09:29 AM
Bump - good work guys.

Well, most of you http://forums.ubi.com/images/smilies/blink.gif

Slickun
02-01-2006, 02:53 PM
Enjoying this immensely.

BTW.

My Pop, many times, agreed almost word for word with the stall and spinning characteristics of the P-51 that we find in the pilot's handbook.

lrrp22
02-01-2006, 03:57 PM
Originally posted by Slickun:
Enjoying this immensely.

BTW.

My Pop, many times, agreed almost word for word with the stall and spinning characteristics of the P-51 that we find in the pilot's handbook.

Howdy Slickun,

Here's what the RAF's AFDU had to say about Mustang handling:



FLYING CHARACTERISTICS

6. The Mustang III is very similar to fly and land as the Mustang 1. <span class="ev_code_yellow">It is therefore delightfully easy to handle. It is as easy to fly as a Spitfire IX with the exception that the rudder is needed whenever changing bank </span>(in order to prevent skid, and to prevent the sight from swinging off). This soon becomes automatic. The engine feels very smooth.


Hmmm.

LRRP

Slickun
02-01-2006, 04:26 PM
I quizzed him fairly often about Mustang vs T-Bolt handling.

Stalls and spins, in his book, were worse in the Jug, something to be avoided.

The Mustang he described much as the P-38 guys describe it...kind of mushing outward. He'd mimic pushing the stick forward. I was struck by this, because I had been "indoctrinated" by many message boards to the fierce and sudden stall and spin characteristics of the Mustang. He did what he usually did, kind of gave me a quizzical look and would describe how he remembered it.

The Pony didn't give as MUCH stall warning as the Jug, but it gave plenty, according to Pop. He said the wings kind of waggled a bit, but you were ready for it because, well, you knew you were getting close to the stall point.

We never talked about 150 octane fuel at all. Wish I would have.

Oh yeah. Dad said the P-51 did a GREAT hammerhead stall. Straight up, stop, and it fell off juuust right. Couldn't do it in a P-40, could kind of do it in the P-47, but you weren't sure which way you were going to fall off. He came out of some with blood shot eyes.

The-Pizza-Man
02-01-2006, 04:36 PM
Someone should try and test it against this
http://www.zenoswarbirdvideos.com/Images/P-51/P-51OLL.gif

Slickun
02-01-2006, 05:17 PM
8 g's at 260 mph indicated stall speed. At speed a pilot could pull all the g's one could stand and not worry about stalling.

Viper2005_
02-01-2006, 06:58 PM
At the limiting speed of 505 mph, it therefore follows that around 30 g would therefore be available if the pilot was strong (and stupid) enough to pull that hard.

AFAIK, IL2 is arranged such that all aircraft break at 15 g.

From this diagram it follows that 15 g is available at around 356 mph IAS which is 572 km/h on the speedbar.

This is testable.

Slickun
02-02-2006, 07:43 AM
That is at 8000 pounds. Most D models, in combat, would be weighing more. B/C/III models is a closer match.

zeno303
02-02-2006, 02:44 PM
FWIW, I read that the 56th FG group pilot's were initially not happy about switching over to P-51s from Jugs, until they realized that their kills went up after the change over to Mustangs.

For all you T-Bolt gearheads out there, I will be posting one of my all time favorite videos "At the Matinee" http://www.zenoswarbirdvideos.com/MATINEE early next week. (I can't be more specific right now on when the video will post because my DSL is down until my idiot DSL provider can fix what they perpetrated.)

"P-47 Assembly" shows how a bunch of mechanics could asssemble a P-47C in a field with wrenches, screw drivers & muscle. Gives some good looks under the Jugs skin. Not to be missed.

Zeno
www.zenoswarbirdvideos.com (http://www.zenoswarbirdvideos.com)

luftluuver
02-02-2006, 10:38 PM
Originally posted by zeno303:
FWIW, I read that the 56th FG group pilot's were initially not happy about switching over to P-51s from Jugs, until they realized that their kills went up after the change over to Mustangs.[/URL]

The 56th FG stayed with their Jugs to the end. At the end they were in P-47Ns. Sure you did not mean the 4th FG.

zeno303
02-03-2006, 08:38 AM
Originally posted by luftluuver:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by zeno303:
FWIW, I read that the 56th FG group pilot's were initially not happy about switching over to P-51s from Jugs, until they realized that their kills went up after the change over to Mustangs.[/URL]

The 56th FG stayed with their Jugs to the end. At the end they were in P-47Ns. Sure you did not mean the 4th FG. </div></BLOCKQUOTE>

That's what I get for relying on my foggy memory. You're right, the 56th did stick with the Jug til the end of the War. FWIW, my primary 56th FG source, "Beware the Thunderbolt, The 56th Fighter Group in WWII," by David McLaren, forward by Hub Zemke, says that the last Jug flown my the 56th was the "M" model.

You may be right that the quote about the P-51 came from a pulot in the 4th FG. I will now be quietlty driven crazy trying to remember where I actually read it. http://forums.ubi.com/images/smilies/blink.gif

Zeno
www.zenoswarbirdvideos.com (http://www.zenoswarbirdvideos.com)

Slickun
02-03-2006, 12:04 PM
And, I read somewhere that the 56th was to recieve P-51H's to replace the P-47M's after war's end.

Bet that went over like a turd in a churn.

LLv34Mokkeri
02-05-2006, 03:11 PM
Originally posted by Buzzsaw-:
Salute

No one flys the P-51's online anymore.

:


Not true I fly it and I like it.

Slickun
02-06-2006, 07:48 AM
BTW, Zeno, you have a GREAT site.

zeno303
02-06-2006, 08:24 AM
Originally posted by Slickun:
BTW, Zeno, you have a GREAT site.

Thanks Slickun!

BTW -- just uploaded the new video features playing "At the Matinee" for February. (Four!)
http://zenoswarbirdvideos.com/MATINEE.html

I'll post the official announcement with all the details here in a day or two.

Regards,

Zeno