p-51B/C

[Rjel]

5 hours ago, ShamrockOneFive said:

I'm not advocating for a change. I was just helping connect some folks on what was done in the past and how it's done now. IMHO I think having it as a modification seems very workable. Quirk with the head movement and all.

Well, as usually happens when replying to a thread such as this, the counter point I was trying to make likely wasn't clear and didn't necessarily reflect your comment alone. Another post was mentioning the B and C as separate aircraft. That led to my comment. I'm happy with the B/C as they are.

[Vishnu]

Jeez. Weather and temperature actually affect the speed of the aircraft?!?!??  If so, I'm impressed.

[Rjel]

3 hours ago, I./JG52_Woutwocampe said:

 

Well I would take it with a grain of salt. Try to do what the spit does, during the first 2 hours, when loaded with fuel. 

 

I just tried it for the first time, its a superb aircraft.

 

And yet, that was exactly what they did in the lead up to D-Day flying missions all over France and the Low Countries. That rather short flight across the channel would have easily left them with enough fuel to fly another 6 hours or more. Not every mission flown by P-51 groups was long range escort, especially during May 1944.

[LukeFF]

20 minutes ago, Vishnu said:

Jeez. Weather and temperature actually affect the speed of the aircraft?!?!??  If so, I'm impressed.

 

Yes ?

[Willy__]

27 minutes ago, Vishnu said:

Jeez. Weather and temperature actually affect the speed of the aircraft?!?!??  If so, I'm impressed.

 

i dont think rain affects it... but wind sure do! also temperature is the main thing, aircrafts will be a lot faster on winter maps!

[-=PHX=-SuperEtendard]

4 hours ago, CUJO_1970 said:

 

P-51B 81" with -7 engine gets a 43mph speed boost on winter map. I got it up to 432 mph on the deck, others even claim more. The G14 by comparison gets an 18mph speed boost, so no. Not the same.

 

The FW190D-9 gets no speed boost at all on winter map and is an absurd 56 mph (91kph) slower on the deck  - complete nonsense.

 

The P-51B with the -3 engine on 130 grade fuel gets a 31mph speed boost on winter map and can do 406 on the deck. No 150 grade required, no -7 engine either, it is just as fast as a K4 DC running all out at 1.98ata.

 

The -7 on 130 grade gets a 36mph speed boost and does 411 mph on the deck on Rhineland Winter.

 

The perceived speed increases in winter are caused by the IAS reading above what it should be, if you take a TAS calculator and adjust for the different temperature compared to standard conditions you will see that the true air speed is mostly equivalent to the standard speed at 15ºC sea level, there will be some differences based on the radiator behaviour and how they affect the drag of the plane (more or less drag by having it closed).

The exception to this is the Dora that is much slower compared to the rest of the planes because of it's engine manifold pressure regulator, it will develop much less manifold pressure in cold temperatures. Only 1.64 ata instead of 1.8 ata at max throttle in the winter maps in QMB which are -15ºC at sea level.

For example taking the Me 262 which it's speed gauge displays TAS above 400 km/h:



Indicated airspeed 826 km/h, true air speed 780 km/h. Measured the time it took the plane to clear one of the 10 km squares and it was consistent with 780 km/h speed.
 

[BlitzPig_EL]

Temperature density on winter maps is modeled?

 

Wow.

[354thFG_Drewm3i-VR]

The new p-51 is now my second favorite plane behind only the cw Spit IX with 150 octane. It can run from anything minus the me-262 which it can easily clobber in a dogfight. Great addition to the sim!

[DeafBee]

15 hours ago, -332FG-drewm3i-VR said:

The new p-51 is now my second favorite plane behind only the cw Spit IX with 150 octane. It can run from anything minus the me-262 which it can easily clobber in a dogfight. Great addition to the sim!

Same for me. Such a great plane to fly.  I think my favorite Spitfire Mk.IX is getting jealous. ?

[Jaegermeister]

I'm still trying to find any problems with it... so far I have failed miserably. 

[Sobilak]

P-51B is my favorite plane. SpitIX is just behind.

In QMB dogfight with AI( Ace ) I'd used WEP 67Hg,  -3 engine, only vs Me262.

Vs 109G14, Fw190A8, Fw190D9   61Hg is sufficient to take adventage.

[CountZero]

Just now, Sobilak said:

P-51B is my favorite plane. SpitIX is just behind.

In QMB dogfight with AI( Ace ) I'd used WEP 67Hg,  -3 engine, only vs Me262.

Vs 109G14, Fw190A8, Fw190D9   61Hg is sufficient to take adventage.

its AI, you could win probably using p-40s or i16s

[CUJO_1970]

On 1/1/2022 at 4:10 PM, dogefighter said:

P-51B 81" can sustain 661 kph on Kuban Autumn at SL with 90% rpm, 0% oil rad and 60% water rad and mix auto rich. With these settings water temp is at max allowed 121C.

IRL Test of P51B at 81" / 3000rpm : 650 kph at SL http://www.wwiiaircraftperformance.org/mustang/rae1501.html

An error of 1.69% which is well within the devs 3% margin of error. Now, that P51 was in a pretty bad condition when they received it and had they also repainted the whole fuselage and not just the wings am sure it would have gained them a few more kph. In any case, as we can see the devs got this FM pretty much spot on, and the claim that P51B is too fast at 81" is false.

 

Where does it say that the P-51 was in "pretty bad condition"? It said the paintwork was, but that is normal for in-service aircraft from any nation - and would be more representative of an in service aircraft.

 

This aircraft was cleaned and underwent modifications prior to testing:

 

"On the Mustang III the wings were cleaned up and the bomb racks and a small bracket at the base of the whip aerial removed giving a total increase of 21 m.p.h. It is estimated that the separate effects were 12 m.p.h. for improved finish and 8 and 1 m.p.h. for the bomb racks and aerial bracket respectively. Replacing the exhausts by Spitfire type stubs gave a further increase of 1 ½ m.p.h.

 

Modifications were done to the aircraft that gave it a 21 mph speed increase. Further:

 

The adhesive patches over the gun ports were loose and were replaced by fabric patches before flight. Except for this minor altercation, the aircraft was flown as received.

 

In the cleaning up tests, the leading 2 ft. of the wing surfaces had to be stripped of paint and repainted. The rest of the aircraft was rubbed down only.

The bomb racks were removed and also a small projecting bracket at the base of the whip aerial.

At low altitudes and at 25 lb./sq. in. boost, the original exhausts are inadequate in providing the optimal exit area. The exhausts were therefore replaced by Spitfire type stubs representing approximately the correct area required. These were the only type available at the time. No exhaust shrouds were fitted in either case.

 

This was a machine specially prepared for a speed test. It had:

 

- Surface improved paint by stripping and repainting

-Remainder of aircraft polished

-wing racks removed (not applicable to our aircraft)

-modified aerial bracket

-gun ports covered

-modified/replaced exhaust stubs

 

It was at least 21 mph faster than typical service aircraft, most likely even a bit faster because the benefit of the sealed guns and the modified exhaust are not given. So, even this specially prepared aircraft is quite a bit slower than what we have in the game - being able to literally cruise on the deck at 409 mph. In summary - the top speed of the RAF Mustang III we have in the sim is quite a bit faster than this specially prepared aircraft. What other aircraft use this standard?

 

But we say of course "the claim that P51B is too fast at 81" is false" ?

 

Now we can also see - the P-51B with -7 power plant and 67" can with no problems do 391 mph on the deck on Kuban (no 150 grade required):

 

 

This is of course also quite a bit faster than actual test data shows

 

http://www.wwiiaircraftperformance.org/mustang/mustangtest.html

 

Spoiler

 

 

A. P-51B-5 43-6883
WRIGHT FIELD TEST
Flight Tests on the North American
P-51B-5-NA Airplane, AAF No. 43-6883  371 MPH

Maximum speed at sea level (67" Hg. manifold pressure & 3000 RPM)

     371.0 MPH
Army Air Forces Material Command
Flight Test Engineering Branch
Wright Field, Dayton, Ohio
24 April 1944
--------------------------------

B. NORTH AMERICAN
4-25-44 V-1650-7 67" HG
The P-51B-15 airplane, AAF No. 43-24777
 361 MPH

 

(These tests were also with gun racks removed)

 

It is the same story with the other P-51B aircraft at all engine and boost settings, as it is with the P-51D as can easily be demonstrated by testing in the sim and then comparing to actual test data - which is plentiful in the case of the Mustang.

=======================================================

 

Of course I'm sure this will be seen as an attack on the P-51 by many. But - for my favorite aircraft the FW190A series - would I be happy if the A8 is doing 375 or 380 mph on the deck? Nope - not realistic is it? Simply ask if you want seal clubbing or do you want something realistic.

 

The P-51, both B and D models are good enough to stand on their own merits without the need of these buffs and other "gamer" settings that can be exploited.

 

 

Edited January 4, 2022 by CUJO_1970

[CUJO_1970]

On 1/1/2022 at 3:28 AM, -=PHX=-SuperEtendard said:

The exception to this is the Dora that is much slower compared to the rest of the planes because of it's engine manifold pressure regulator, it will develop much less manifold pressure in cold temperatures. Only 1.64 ata instead of 1.8 ata at max throttle in the winter maps in QMB which are -15ºC at sea level.

 

Thanks for the info on the speeds/calibration! (but even after converting the speed gains do not seem plausible)

 

As far as the above, I don't understand how this can be with Dora unable to reach full boost - especially as German flight tests specifically reference the motor reaching full boost 1.7ata 1900PS (early D9) and 1.8ata 2100PS (after MW50) during these same flight conditions in cold temps in both December and January months during the war.

 

This is a topic though for another thread so I'm going to ask a bout it in a new one so this one doesn't wonder further off topic.

 

Thanks again.

[AndytotheD]

The Dora uses a different method of measuring the charge air going into the engine. Instead of using boost pressure, it uses mass air flow. Colder air is denser and will generate less pressure for a given mass. 

[Denum]

On 12/31/2021 at 8:54 PM, Vishnu said:

Jeez. Weather and temperature actually affect the speed of the aircraft?!?!??  If so, I'm impressed.

Oh yeah.

 

Trying flying the P47 on a hot summer map then go for a rip in the winter.

 

You'll really notice it there! 

[[-=BP=-]Slegawsky_VR]

2 minutes ago, [-=BP=-]Slegawsky_VR said:

VR G2, 

Hood is without sound

- missing sound and chain is moving.

?

 

[ACG_Cass]

7 hours ago, CUJO_1970 said:

B. NORTH AMERICAN
4-25-44 V-1650-7 67" HG
The P-51B-15 airplane, AAF No. 43-24777
 361 MPH

 

(These tests were also with gun racks removed)

 

Only the 75" was run without wing racks - http://www.wwiiaircraftperformance.org/mustang/p-51b-24771-level-blue.jpg

 

"It will be noted that all tests were run with the wing racks installed. Speeds would be approximately 12 mph faster with the wing racks removed as shown by the dash line curve on the Speed vs Altitude Curve"

 

Also shows 364, not 361. 

http://www.wwiiaircraftperformance.org/mustang/P-51B_24777_Speed_Altitude.jpg

 

Here you have 362, again with wing racks so that would need to be corrected. 

 

And here you have the engineerings divisions charting of the flight test data that shows it hitting 385mph at 67"

 

http://www.wwiiaircraftperformance.org/mustang/p-51b-engdiv-na-flighttestdata.jpg

 

 

Also here's a D with wing racks hitting 375mph at 67"

 

http://www.wwiiaircraftperformance.org/mustang/p51d-15342.html

 

From that you can see the speed increases (IAS, TAS would be even more) available from the oil and coolant shutter positions at 15,000ft 46" 2700rpm. These gains being higher at sea level running at full speed seems possible.   

 

http://www.wwiiaircraftperformance.org/mustang/P-51D_15342_Shutter_Calibrations.jpg

 

 

I really don't feel like the achievable speeds are that unrealistic based on all the data we have on the plane. 

[ICDP]

So is the P51B the new clown wagon? 15-20mph too fast at SL but all the usual suspects call it "fine".

Edited January 4, 2022 by ICDP

[Rache-der-Boote]

39 minutes ago, ICDP said:

So is the P51B the new clown wagon? 15-20mph too fast at SL but all the usual suspects call it "fine".

 

Oh look, an Axis apologist with the "Tester" tag. What a surprise!

[LuftManu]

From what I read and saw, the 51 seems reasonable and on point with sources. I won't add anything more as some gentleman has alrady given too much time to explain basic things.

 

 

[purK]

Is this a bad time to ask for 150oct fuel for P38? ?

But seriously, the P51B seems to match these irl speed tests quite well with the proper settings and air temps. As for the speed "tricks", even 109s/190s have some tricks up their sleeves to add some more kph, it's not something specific to the P51.

 

Edited January 4, 2022 by Krupnski

[357th_Dog]

1 hour ago, ICDP said:

So is the P51B the new clown wagon? 15-20mph too fast at SL but all the usual suspects call it "fine".

So years of prophanging, super-300 level 109's and hyperalpha 190's but now the P-51B is the problem?

Maybe you should have done a better job as a tester

[ACG_Cass]

1 hour ago, ICDP said:

15-20mph too fast at SL

 

According to what? Specifically, what data/tests have told you that it's 15-20mph too fast at SL.

[Barnacles]

Just now, ACG_Cass said:

 

According to what? Specifically, what data/tests have told you that it's 15-20mph too fast at SL.

Probably the IRL tests which specifically mention they were done at 3000 rpm with auto rads. So in game of course you're going to be able to get better speeds, using manual radiators and reducing rpm. (which IRL tests show reduce drag / prop / losses) 

[ICDP]

Like the times I have pushed for the P47 to have altitdue power corrected as it is currently too low?

Or how I pointed out that the P51D performance was too low as our in sim P51D could only reach real speed without bombrack, yet real tests were done WITH bombracks.

Or how I asked why the in game 190A3 was too fast at altitude.

 

It's funny how these people getting at me are the ones showing their true bias.

 

The problem with some planes allowing these "boosts" due to reducing prop pitch etc, is that we have no real world test data showing how much performance should be affected.  So in the end we get guesswork.

Edited January 4, 2022 by ICDP

[StaB/Tomio_VR***]

P-51B doesn't have G-suit if mission is set after Sept. 1944 ??

[purK]

3 minutes ago, StaB/Tomio_VR*** said:

P-51B doesn't have G-suit if mission is set after Sept. 1944 ??

No it doesn't get a G-suit, although it really would be nice to have it as a selectable aircraft mod since they definitely still used P51Bs after Sept. 1944. Same thing for the P47D22.

[BlitzPig_EL]

Gents, let's all leave our national biases out of this, also let's not go down the road of personal bashing.

 

We all want to get at the truth, or we should want that, so let's calm down, present our data, and not just our "feels", and let the team sort this out.  We know that they are looking at the B's supercharger gear change programming, because something is amiss there. (It's very different from the D, even with the same -7 engine).  Has anyone tested the B at sea level using the settings used for the "in the day" figures that are out there?  If yes, and the numbers fall within a few percent of the real numbers, then we are good.  If using gamer tricks, which is done no matter which "side" people fly for, results in out of the ordinary performance, for any plane, then there is a deeper issue buried in the physics programming of the sim, and isn't a matter of "nerfs" or "buffs" for individual aircraft.

[MeoW.Scharfi]

47 minutes ago, ICDP said:

Like the times I have pushed for the P47 to have altitdue power corrected as it is currently too low?

Or how I pointed out that the P51D performance was too low as our in sim P51D could only reach real speed without bombrack, yet real tests were done WITH bombracks.

Or how I asked why the in game 190A3 was too fast at altitude.

 

It's funny how these people getting at me are the ones showing their true bias.

 

The problem with some planes allowing these "boosts" due to reducing prop pitch etc, is that we have no real world test data showing how much performance should be affected.  So in the end we get guesswork.

 

And yet you call the P51B "the new clown wagon" because you THINK it's a few mph too fast.

Every plane in here gets a few kph out when decreasing the prop pitch otherwise the prop causes too much drag, except Tempest and P38.

Everyone keeps calling the Tempest an UFO plane but infact it's still too slow at sea level, it should be a bit slower than P51B with 81 inch.

[CountZero]

biggest gain in speed on 51s is not reducing rpms, that gives you few mph and less and less more MP you use, its seting radiators to best position what makes it so mutch faster then when things are left on auto. Why would that be considered gamer tricks lol are we not closing and opening radiators on other airplanes to get better speed, problem on 51s is auto control dont know 1/3rd open is best position so it offten closes it more and thats reduction in speed in this airplane unlike in others where usealy 0% is best position.

 

edit:

Its like insisting that you should fly yak7 or p-39 with 0% rads, insted whats best postion for them like 50-60% open, and call it gamey if you use best drag position and gain speed insted using 0% and be slower.

Edited January 4, 2022 by CountZero

[ACG_Cass]

3 hours ago, ICDP said:

So is the P51B the new clown wagon? 15-20mph too fast at SL but all the usual suspects call it "fine".

You can't come flying in on a forum, not comment on any of the other data and throw in a statement like that and not expect to rustle some jimmies. Even @CUJO_1970 is looking through tests and data and posting reasoned arguments around why it doesn't seem right to him. 

 

The number that matters is the one that matches the test at the same conditions. Flushing your rads should give you a speed boost is reasonable, there's actual data from tests they conducted on it and less drag = more speed usually makes sense. The RPM trick would work IRL but would be horrible for the engine and no-one is going to min-max in the same way we do in the game. You can absolutely argue that the final number you can reach is a little too much, but if they ran a test with the settings we have with the idea they will scrap the plane when it lands, I don't think the figures would be too far away. 

 

 

[MisterSmith]

We haven't quite crossed into full ad hominems or prohibited FM discussions here but scale it back or there will be some timeouts coming. There is enough on the FM's to move it to that thread but I'll let it stand as there is also enough general B/C talk to keep it in General for the moment.

 

Discuss data all you want in the appropriate forums but the personal stuff has to go. Going too deep into FM, other that the speeds, will probably get it moved.

 

Your friendly neighborhood Smith

[354thFG_Drewm3i-VR]

6 hours ago, ICDP said:

So is the P51B the new clown wagon? 15-20mph too fast at SL but all the usual suspects call it "fine".

Did you even read the post from Cass above yours? The TAS is pretty much dead on. 

Edited January 4, 2022 by -332FG-drewm3i-VR

[-250H-Ursus_]

Well the snowball is currently descending from the mountain. 

P-51B is great, has the same weak spots as a P-51D for facing in combat so is not THE deal in combat. Still a fearsome foe 

[CUJO_1970]

10 hours ago, Krupnski said:

Is this a bad time to ask for 150oct fuel for P38? ?

 

You can, but why would you want to?

 

"In the spring of 1944, a technical expert with some drums of 150-octane gasoline showed up at our airbase. This they claimed would give us 10 percent more power on our engines. The stuff was so corrosive everybody had to wear rubber gloves when fueling an aircraft. After one or two ships tried it out, we loaded the whole group and took off on a mission. After 90 minutes out on low cruise, many engines began to run rough followed shortly thereafter by many engines throwing a rod. The whole mission was aborted and we staggered back to England. On landing, examination of the plugs showed every one to be so fully leaded that they looked like a solid chunk of metal. Every plug in the squadron had to be changed plus half of the engines. Needless to say, the expert and his gasoline were drummed out of England. The test unit in the United States never tested the gasoline under our conditions"

-Major General Ed Giller, USAF

https://en.wikipedia.org/wiki/Edward_B._Giller

 

- Now in time despite this they tested new 150 grade fuel composition that did work on the Allison in the P-38 (at least theoretically)

 

However: the engine required extensive modifications including a new water pump and a coolant system pressurization kit...and during this time of testing engines continued to fail for other reasons, and on regular fuel: the engine and it's systems could never deal with extreme cold high altitude conditions, particularly in winter time in Europe and the whole system didn't lend itself to pushing it even further when it was barely working in the first place.

 

This is discussed in Callum Douglas excellent new book The Secret Horsepower Race on p. 376 and 377 etc.  In short, the engine failed constantly, both on the bench (one within 90 seconds) but especially in the cold air over Europe, especially in winter, and for a large variety of reasons.

 

Finally: the only way to get the P-38/Allison system to work with 150 grade/high boost was to completely delete the whole intercooler system and replace with new system in P-38J (in addition to the other modifications already mentioned) and eventually the P-38 passed it's war emergency rating at 3000 rpm with 150 grade fuel.

 

But - the engines continued to fail. The whole engine and it's ancillary support systems were just not engineered for these high boost setting and by the time Allison could ever get things to work it was way too late.

 

So people keep asking for 150 grade fuel for P-38 but it is not a real option historically. Just be glad we have P-38 at all...and especially smile next time you fly it at high altitude on any winter map ?. What we should be asking for with P-38 instead of ones that weren't used is to asked for those that were used P-38F/G/H

 

 

 

17 hours ago, dogefighter said:

In summary - the top speed of the RAF Mustang III at +25 lbs we have in the sim is spot on.

 

Edited January 5, 2022 by CUJO_1970

[AndytotheD]

According to the same book the P-38J was cleared for 150 octane on May 6th 1944 (ref pg 377). According to a source on WWII Aircraft Performance every 8th Air Force fighter was apparently using 150 octane by D-Day and the P-38, while on its way to being phased out, was certain it still very much among this number. 

[purK]

4 hours ago, CUJO_1970 said:

 

You can, but why would you want to?

So people keep asking for 150 grade fuel for P-38 but it is not a real option historically

 
Feel free to read this thread, there's plenty of evidence for it. The entire 8th AF, including the 479th FG more specifically started receiving shipments of 150 octane fuel to their airfield (Station 377 Wattisham) on June 10th, 1944. The main change required was some new spark plugs.?
 

 

 

Edited January 5, 2022 by Krupnski

[Bremspropeller]

18 hours ago, Krupnski said:

No it doesn't get a G-suit, although it really would be nice to have it as a selectable aircraft mod since they definitely still used P51Bs after Sept. 1944. Same thing for the P47D22.

 

That raises other, interesting questions.

How were the airplanes modified for the g-suits (hose-connectors, air-supply, etc) and where was the modification incorporated?

 

I went through several unit-histories over the last two days and I couldn't find a lot of pics of pilots wearing g-suits in the first place.

Turns out, a lot of pictures of pilots and their aircraft are just for posing and photo-ops...

 

That in turn raises another question: Were most photos just really posed, or was the percentage of flown missions in g-suits really low? Were all aircraft equipped with connectors? Were the suits just not flown often (maybe out of convenience)?

 

Then there's the question how the mods were shipped to the frontline-depots or squadron MX. Would they priorize 8th AF units and only then go for the 9th?

IMHO the g-suit would be a good item to make a modifier, rather than just hard-wire it to a date.

[Rjel]

I've found since flying the B that I've only experienced blacking out twice. I got dimmed vision once or twice more but overall, very little. I think the introduction of pilot physiology has improved my flying so that I'm not yanking and banking so much or so often as I did before.