Author Topic: Perk the P51 B (Read 1959 times)

Kweassa · « **Reply #45 on:** September 13, 2002, 05:38:52 AM »

I still don't seem to see anyone with an effective counter-explanation for the top speed of the P-51D. ammo's post is very informative, but its basically a "guess" based on the P-51A. Hohun's post seems logical, too, but yes, it's basically an explanation on why the P-51D was slower than the factory charts... you can't conclude on how fast the P-51D was based on that.

Don't get me wrong, I find it hard to believe what Maddox disclosed, too... The image of the "lightning-fast P-51D" is still hard embedded into my brain, too.

I'm just stating that these different views and interpretations are pretty interesting to watch.

I remember the heated debate when IL-2 first came out concerning the roll-rate performances of the 190. One thing for certain is, like many things, there are different views on flight modelling of a certain plane.. and since IL-2 is probably the first case where the developers use research data that is not primarily based on Western tests, it is very interesting to note that maybe, just maybe some of the perceptions and images of a certain plane we held for so long might not be right. It's a possibility I guess

Whatever it is, I don't think we can just dismiss it as "roadkill".

...

Would there be any other instances of "real tests" concerning the P-51D other than the case Maddox refers to?

It'd be interesting to know...

Wilbus · « **Reply #46 on:** September 13, 2002, 06:43:32 AM »

Then again, when Il2 first came out the roll speed of all planes were total BS, specially the 109 and P39. (thinking about the Demo now)

Think they've got it pretty good now though.

-ammo- · « **Reply #47 on:** September 13, 2002, 08:44:08 AM »

hohun/kweassa--

I have been promised more information forth coming.

Kweassa · « **Reply #48 on:** September 13, 2002, 09:33:07 AM »

Another thing crossed my mind as I read Hohun's post.

Would the radiators on some planes effect the plane so much as drag down nearly 20mph from its top speed, and make the engines overheat up to such dangerous levels?

If so, maybe modelling some of the more various aspects of the planes in AH might be farely enjoyable.

Things such as engine overheat(not as drastic as IL-2 though..), management of radiators, a bit more profound RPM control, opening/closing cockpits for the planes known to fly them open in some situations.. and maybe supercharger gears and stuff..

If such management issues were put into AH, I have a feeling a lot of planes would feel totally different than we're used to

It'd be very cool to watch how managing the more detailed aspects of the plane would work on our normal sense of "dogfight"..

...

Oh dear. I've done it again.. I've hi-jacked the thread..

SpinDoc1 · « **Reply #49 on:** September 13, 2002, 10:11:22 AM »

Kweassa, this sounds like a similar idea I posted some time back. I suggested random parts/equipment failures to simulate the real life aspects of planes at the time. How many times have you read stories of P51's taking 48 fighter with 4 extra, and then when some planes had 'technical difficulties' the extras would fill in. This aspect of realism would greatly hamper the MA, but I think in the combat theater or as an option for something like H2H would challenge everyone greatly. Another example, in real life, the original P51b's couldn't fire while turning because the belt loaders for the .50's were at a 45 degree angle inside the wings, or else some guns would jam? How about gun jamming or overheating? That would be a VERY interesting aspect added to AH. I'm not saying we need these things, I'm just suggesting it as an addition once HTC creates most of the WWII planes. Hope HT is reading this thread, great posts guys!!!

Jason

Pongo · « **Reply #50 on:** September 13, 2002, 10:12:26 AM »

Funked.
Thats why I thought those numbers were interesting. they were USAAF and RAF numbers where they not?
The cooling system for the pony was supposedly heavily influenced by a visit of the designer to the ME factory.
I think that was in planes of fame volume one...

HoHun · « **Reply #51 on:** September 13, 2002, 12:10:53 PM »

Hi Kweassa,

>If so, maybe modelling some of the more various aspects of the planes in AH might be farely enjoyable.

Things such as engine overheat(not as drastic as IL-2 though..), management of radiators, a bit more profound RPM control, opening/closing cockpits for the planes known to fly them open in some situations.. and maybe supercharger gears and stuff..

I'm not sure it would make much of a difference for performance or even for pilot work load. The late-war planes had many automatic controls, and thermostatically controlled radators were pretty common too. Often, you'd only override the automatic to get full fuel economy.

The early-war planes varied a bit more in their degree of user-friendlyness, I think the Me 109 for example was quite good while the F4F required a lot of manual attention, with most other planes somewhere in between.

Still, it would be nice to have the "character" of an aircraft reflected in the way you describe, even if it might not impact performance very much :-)

I'd actually be ready to hit the "raise gear" key 28 times after each takeoff in the Wildcat to simulate cranking up the wheels manually! ;-)

Regards,

Henning (HoHun)

Wmaker · « **Reply #52 on:** September 13, 2002, 12:11:09 PM »

Quote

Originally posted by funkedup
I'm talking about manufacturer's data, not USAAF or RAF data. If people want to say that NAA was lying then the discussion ends, because we can apply that to any other organization who tested aircraft.

I generally agree that if we start throwing lying accusations around with out any proof we could easily do that in every direction. Mr. Gruenhagen obviously thinks he has the proof to say so. Personally I'm not going to judge if it's true or not. But I can understand if a purchaser has doubts on manufacturers data. But as I said: I see what you mean.

"Report: NA-5798
Title: "Flight Test Performance for the P-51B-1
Date: January, 1944
Test Weight: 8,460 lbs
High Speed: 453 mph true airspeed at 28,800 feet at 67" HG and 1298 HP, war emergency power, high blower, critical altitude."

HTC's help pages show Normal loaded weight of 9245 lbs for the P-51B-15. That's 785 lbs higher than the P-51 in NAA test. Weights of P-51B vary 9200 lbs to 9400lbs depending on the source. So they are well inline with HTC's weight. Also I doubt the NAA-test a/c had its wing hardpoints attached. This is just a guess based on various pics I've seen of P-51B-1 test a/c. Since your quote on the test doesn't have a a/c serial number it's hard to determine if any of those pics match the plane in NAA test. F4UDOA said somewhere on this board that to his knowledge F4U-1 is the only plane in AH where hardpoint drag is taken into account because it was almost always attached in operational planes. I don't remember seeing pictures of operational P-51Bs without their wing hard points. So I don't know if they are calculated in the FM or not. I think they should be though.

I tested AH's P-51B's top speed at 29000ft (altitude where HTC's speed chart shows the highest speed). I got a result of 440mph with WEP on.

So, the difference is 13mph which well inline with the weight difference and the hard point drag IMO.

Quote

Originally posted by funkedup
Just be glad HTC modeled the B so conservatively.

I'm feel very tempted to use the big W-word here but since the discussion has been very civil and interesting here so far I'll try to cool it.

J_A_B · « **Reply #53 on:** September 13, 2002, 01:13:30 PM »

"Would there be any other instances of "real tests" concerning the P-51D other than the case Maddox refers to?"

This is why Oleg's case is BS....his claim of "lack of real tests" is simply false. It just isn't true.

If you want, look up for example tests in 1957 of the last ANG P-51D before it was donated to Wright-Patterson's museum. Those tests were done with the airplane in normal WW2 config and matched the 437 MPH figure. The Navy tested the P-51B and did a fair amount of work with the "D" too. There are numerous Army tests available for different versions of the P-51. If all that wasn't enough there is information available from other countries that used the P-51D as well as from private collectors, although in the case of private colectors you must take note of what modifications have been made to the airplane (a few surviving P-51D's are kept very close to WW2 condition). There is more good data available for the P-51D than for any other WW2 fighter that I know of.

Why aren't I looking it all up and posting it myself? I don't feel like wasting several hours of my life refuting a claim as obviously false as Oleg's claim. The fact is, Oleg's "material" is nothing more the the absolute worst data he could find. Whether it is left over Russian propaganda from the cold war or just an attempt to get attention (free advertising) I don't know. I suspect it's a combination of both though.

(I read Oleg's quote, then think of a lot of players in AH who complain about the Yak-9U and LA7..."Russian planes couldn't have been THAT good!")

J_A_B

H. Godwineson · « **Reply #54 on:** September 13, 2002, 01:19:37 PM »

The P-51B was aerodynamically cleaner than the later D model Mustang. The bubble-canopy imposed a drag-penalty, although it was slight. Therefore the B model was a few mph faster than the D model. Top speed of the D model, depending on loadout, would be above 440mph.

Comparing the performance of the P-51D to that of the Ta-152 is like comparing apples and oranges. The Ta-152 was designed for high-altitude interception, it's main targets being Allied bombers. It's engine was maximized for operation beyond the reach of any Allied fighter. This made it ideal for its main role, and for photo-reconnaissance. While it would out-perform the P-51 at altitudes above 35,000 feet the Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.

Regards, Shuckins

Wilbus · « **Reply #55 on:** September 13, 2002, 01:42:03 PM »

Quote

Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.

Sorry but the wing had no proeblems what so ever with high speed dives, it couldn't handle as much G loading as the earlier 190's due to longer wing but the wing was greatly strenghtened and could handle a good amount of G's.

It was actually on par with, if not superior with the P51 D at all altitudes not only above 35k. Combat reports also report it being on par with or superior the Spit 14 and Tempest at most alts aswell, except for the tempest greater low alt speed and spits better climb at the deck (not much better) and it's better turn rate.

Will post a nice little comparion "chart" (text only) which was made in Germany near the end of the war.

HoHun · « **Reply #56 on:** September 13, 2002, 01:52:07 PM »

Hi Shuckins,

>Comparing the performance of the P-51D to that of the Ta-152 is like comparing apples and oranges.

The original comparison at the beginning of this thread was between the P-51B and the Ta 152, and I think this is a fair comparison as the P-51B had the engine that was originally developed to give the Spitfire IX superior high-altitude performance.

Of course, the Ta 152 was highly specialized and used more advanced technology as it came out much later, but the P-51B was a very good high-altitude fighter too, and if it outperforms the Ta 152 at the latter's best altitude in AH as Wilbus claims, I'd say there's no fruit mix-up problem involved ;-)

>the Ta-152's wings proved to be too fragile for high-speed dives, limiting it's usefulness in combat.

I don't think speed was the problem, but the Ta 152's long wings were G limited. I think they were designed for around 6.5 G, meaning that it had a safety margin for up to 9.75 G by standard design practices. The P-51 could be stressed quite a bit more, so it really had the edge in instantaneous turns. The Ta 152, however, undoubtly had the edge in sustained turns.

At high altitudes, high G situations aren't much of a concern as the thin air just doesn't provide enough lift to overstress the wings. The Ta 152H-0's climb & combat power top speed of 720 km/h @ 10.7 km work out to just 400 km/h IAS, which just isn't enough for more than (maybe) 6 Gs.

Accordingly, the (comparatively) low G resistance of the airframe didn't matter much in the role it was designed for. At lower altitudes, this might have been different, and I think a Fw 190D-12 with the D-9's sturdy airframe and the Ta 152H's engine might actually be a better overall compromise :-)

Regards,

Henning (HoHun)

funkedup · « **Reply #57 on:** September 13, 2002, 01:55:26 PM »

Quote

Originally posted by HoHun
Hi Funked,

>If you can't see the superiority of the P-51 radiator/oil cooler ducting over the 109, you shouldn't be posting here.

You shouldn't dismiss it so lightly :-)

The Me 109 radiator, after it was completely redesigned for the Me 109F, featured a boundary layer bypass duct and continuously variable intake and outlet cross sections, and that's technologically very similar to the P-51's radiator system.

The actual layout of course differed, but the late-series Me 109 radiators were quite sophisticated and much more efficient than the early-series underwing "boxes" :-)

Regards,

Henning (HoHun)

Good point, you are right. I thought of Me radiators and pictured an Emil.

Wilbus · « **Reply #58 on:** September 13, 2002, 02:00:10 PM »

Hohun said it pretty good, for the Ta152 H-0/1 the max G was said to be 6.5, all designers use a safety margin of, usually 50%.

Another thing was that pilots during WW2 never pulled 9 G's, nor did they hardly ever pull more then 6, maybe 7 tops so losing a wing due to high G's wasn't common. The Ta152 DEFIANATLY did not have any problems what so ever with high speed dives, it was designed for high speed at all altitudes and could dive just as good, if not better, as any other 190.

Btw, here's the old speed chart that goes above 30k. Only have it for the Ta152 though

F4UDOA · « **Reply #59 on:** September 13, 2002, 03:49:51 PM »

Wow,

Of all of the A/C in A/H I would actually question the real life performance of it would be the Soviet built fighters ala the La-7 and Yak-9. If I'm not mistaken aren't the AH models flown on pre-production no-combat loaded test planes??

The most undermodeled I believe would be the Japanese plane set. When tested they virtually all were superior to commonly accepted test data albeit with better fuel that the Japanese had at the time.

As far as allied A/C go the Brits tested Navy and AAF birds while the Navy was tested the Mustang, FW190, Zero and others repeatedly.