P-40 turn rate/Flight model check

[Venturi]

I know very well what Sakai expressed. Keep in mind he had high opinions about most of his opponents, which also tells that he was conscious of not underestimating any opponent. He also considered the same way F4F and few other aircraft, not to mention Hellcat. Does it say anything about aircraft flying qualities ? Not exactly. Interesting that you discount Sakai's opinion when it suits you.

 

I can provide another quote from a different place, New Guinea, when recalling 1942 combat experiences of RAAF No. 75 Squadron, pilot Pete Masters said:

"There was much more we know now that we didnt know before we got to New Guinea, like the ability of Zeros to outperform us, contrary to what we had learned before we arrived. We were told that Japanese Zero was an upgraded copy of he Harvard Trainer as used by the Empire Air Scheme in Canada. It was underpowered and flimsy with very light aluminum and canvas cladding sometimes joined by canvas at the extremities. It had no armour plate to protect the pilot, and although it was reputed to fly higher than the Kittyhawk, it was also much slower and inferior in almost all its characteristics, including firepower.

 

I am now sure that all this misinformation came about because very few Allied fighters had encountered Zeros in combat proper to New Guinea and those that had in Malaysia, the Philippines, or elsewhere had never had a chance to examine the real specifications of this amazing aircraft in close quarters. In fact when I at last saw a Zero on the ground and crawled all over it I too was amazed at the rigidity of its structure and its apparent fighting qualities from the cockpit. In our combat assessments at Port Moresby during the 44 days we fought, we soon concluded that head-to-head combat between Kittyhawk and Zero was unwise, and at all altitudes above 20,000 feet was simply dangerous.

 

They were much more maneuverable and could outclimb us in the ratio of two or three to one. What they didnt have was our weight and pilot protection with 1/2 inch armour plate behind the pilot and in the firewall. Our battle plans therefore always included a desire to get above the enemy, if possible into the sun, and then to break away and come back for another shot. If we had height we could always get away from the Zero but with equal skills as pilots on both sides, the Zero always had the advantage at the same height and also could maneuver much more effectively, especially above 20,000 ft where the Kittyhawk would tend to "fall out of the sky".   

Eagles of the Southern Sky by Luca Ruffato and Michael J. Claringbould, Tainan Research & Publishing 2012, page 278.

Obviously, they did not know how to fight against a Zero in a P40. Something that was learned just fine later on, in fact Cpt. Bong did well in a P38 against Zeros, which is a much less maneuverable plane than the P40. Same principles apply and they are AVG principles - do not dogfight against a more maneuverable opponent.

By the way, these were also the orders given to Luftwaffe pilots against the P-40... see where I'm going with this?

 

 

I'm not even going to address that linked article, it has no sources listed and contains multiple errors. Sure, and they are there only to prove a point, that your opinion is ALSO just opinion, and has the additional point of being 70+ years secondhand whereas the pilots were in the planes. Stick to numbers Venturi, like Crump, Holtzauge or Jtd do. Second hand opinions, particularly from very different front, wont tell you much. Thanks sonny, sounds like advice you should also take. By the way, the Zero's superiority in low speed maneuverability didn't help it from being competed with by the P40 just fine... 

Edited January 3, 2017 by Venturi

[Crump]

Here we go:

 

 

The problem of devising instrument systems for the accurate measurement of the speed and altitude of aircraft has been the subject of a great many research investigations during the past 50 years.

 

 

Since a trailing bomb, like static-pressure tube, may have static-pressure error, this error should be determined (by calibration in a wind tunnel) so that corrections for the error can be applied.

 

 

 

 

The accuracy with which free-stream static pressure is measured with a trailing- cone system depends on the configuration of the cone system (size and shape of the cone and position of the orifices ahead of the cone (ref. 6)), on the distance of the cone behind the aircraft, and on the type of the aircraft (size, configuration, aim; propulsion system). Because of the uncertainties associated with each of these variables, trailing-cone systems have not been considered suitable for the basic calibration of an aircraft static-pressure installation.

 

http://www.dtic.mil/dtic/tr/fulltext/u2/a280006.pdf

 

That is in 1974 NASA terms which I am sure was far less accurate than 1940 RAE measurements.

[=362nd_FS=Hiromachi]

 

 

Interesting that you discount Sakai's opinion when it suits you.

Do I ? I think you are seeing more than there is.

 

 

 

Obviously, they did not know how to fight against a Zero in a P40.

They did know how to fight them as is stated in mentioned above quote. To utilize altitude advantage, gain speed and energy, hit target and disengage. Nothing different from later tactics. What they lacked was combat experience, but this could be applied to so many other squadrons.

 

 

 

in fact Cpt. Bong did well in a P38 against Zeros, which is a much less maneuverable plane than the P40. Same principles apply and they are AVG principles - do not dogfight against a more maneuverable opponent.

But that wasn't your initial point. Eric Shilling assumptions were vague, he was drawing conclusions on matters he had no personal experience with and this was taken as a fact. Not opinion.

 

 

 

Sure, and they are there only to prove a point, that your opinion is ALSO just opinion, and has the additional point of being 70+ years secondhand whereas the pilots were in the planes.

I never said it's anything more. It is my opinion, however its also based on sources which I quote and indicate. Anyone can write an article over the web this days, what makes the difference is ability to verify it which in such cases cannot be done.  

 

 

 

Thanks sonny, sounds like advice you should also take. By the way, the Zero's superiority in low speed maneuverability didn't help it from being competed with by the P40 just fine... 

I learned that long ago, dont you worry. This is why I've spent years accumulating documents about Zeros and will use them when time comes for Midway.

You mean like No. 75 Squadron P-40 E-1s ? Or 49th Fighter Group with later support of RAAF No 77 Squadron over Darwin in 1942 ? P-40 was a good aircraft, no doubt about that and it did what it was supposed to do, but it also had flaws.   

[MiloMorai]

The US government didn't think too much of the P-40 and Curtiss.

http://www.aviation-history.com/engines/Truman_Committee_SRes71.pdf

[Crump]

 

Old versus New Past

 

In the past the PEC flight test technique used circular differential pressure indicating gauges, a static pressure bomb or cone and a nose boom for total pressure as well as side slip angle.

 

 

• The gauges have systematic errors due to the design and are difficult in use, as the indicator needle is always fluctuating during flight. They need to be calibrated before the use, considering the hysteresis and friction.

 

• The difference in length of the sensing lines can introduce errors.

 

• Only limited use for climb and descent – Lag Error

 

• The analysis is time consuming as all the calibrations have to be included.

 

• The tests are very time consuming as every flight condition needs to be stabilized before the readings can be taken. (that means the atmosphere must be smooth too)

 

file:///C:/Users/Owner/Downloads/assets-European-Telemetry-and-Test-Conference-etc2014-34.-European-Telemetry-and-Test-Conference-6.3-etc2014%20(1).pdf

[Venturi]

 

Yes, compared to the P51 available at same time, it is behind there is no doubt.

 

The US government didn't think too much of the P-40 and Curtiss.

http://www.aviation-history.com/engines/Truman_Committee_SRes71.pdf

Sure. The P51 should've been the choice, with a two stage Allison instead of the packard Merlin, no doubt.

 

But to say the plane was totally outclassed in 1940 and 1941 by its contemporaries the Zeke and Me109e, is false.

 

It performed worse in some areas, and better in others. As I have said before, no one plane of any major nation was completely outclassed by another's in all regards. The 1940 hurricane could outturn the 109e but was slower and could not climb as well. The 1940 Spit could outturn the 109 and was marginally slower than the 109e.

 

By all accounts the P40e could outturn the Bf109e at high speeds, most usually because of much better high speed control authority, could roll at high speeds more quickly for the same reason, had a similar top speed and dove much better. Downsides, it accelerated less well. It climbed poorly. It is not a world beater. It is not the best or second best. But it is better than a hurricane and it could hold its own if flown with kilnowlefge of its strengths vs the opponents weaknesses.

 

Right now, it has no comparative strengths and I pity the poor fool who flies it in multiplayer or in single player alike. It also does not represent history accurately, which is more important.

Edited January 4, 2017 by Venturi

[Farky]

 

"A more forward centre of gravity position of 17.1" aft may be obtained when the aeroplane is in light loaded conditions of Tare weight PLUS (!!!) a light pilot of 170 lb. and fuel reduced as in para. 4.2" i.e. "... fuel reduced to a suply sufficient for a half hours running of the engine at maximum power permissible at ground level". Ok - so then oil, which is 158lbs? That magically disappeared from the "empty" aircraft which flew? What other things were double-counted for?

 

I am not author of this report, so I don't know about oil. All I'm saying is that report do not describe Tare weight as a "light loaded condition with zero ammunition, and fuel sufficient only for 1/2hr running at max power, with a 170lb pilot.". That's it.

 

 

Weight in RAF report is right, because it is the result of the actual weighing. There is no room for speculations and is it fully consistent with some other data. Not all of them of course, but most of them. So then how is there not room for speculation? You realize this means CLmax must be around 2.0... show us some data before concluding this because I for one have one USAAF source saying one thing, and another saying something different.

...

So who is right? More importantly, which is the "standard" load and what is that load in the game? 100% fuel? You do not know so it is premature to assume.

 

Again, I am just saying that Boscombe Down guys do not "messed up on the weights" or "fudged the weights". Weight in RAF report is right, because it is the result of the actual weighing. As for different sources with different weight - there are also USAAF reports with full standard weight over 8500 lbs. More about them tomorrow.

 

Who is right? All sources are valid, it is about different definitions of standard load and different equipment. Again, tomorrow. But real quick - there wasn't universal "standard load" for all air forces around the world.

 

 

By the way, the guns weight varies too, RAF report - 463lbs for 6x .50cal... USAAF report - 384 lbs

So does the oil, RAF report - 17.5gal, 158lbs ... USAAF report - 16gal, 120lbs (1.5gal of oil does not weigh 38lbs!)

Wireless... RAF report - 160lbs plus another 147lbs for accessories, USAAF report - already has radio in "empty" or "tare" weight of 5982lbs!

Gun camera... RAF report - 10lbs, USAAF report - ABSENT in standard load, but when present, 3lbs!

 

Etc, etc, etc.

 

Right, weight varies for lot of items.

Guns are lighter in US source, misc. Equipment for guns is heavier.

US pilot + Parachute is lighter.

Wireless - diferrent radios and accessories

Gun camera - different type. RAF report is with underwing type gun camera, US with gun camera on gunsight.

Armor plate - in RAF report part of the Tare weight.

Fuel load - slightly different.

Oil - of course that 1.5gal of oil does not weigh 38 lbs. But 5.017 US gal of oil does weigh 38 lbs. Again, US vs. Imperial units. 17.5 Imperial gallons = 21,017 US gallons (158 lbs).

 

More details tomorrow.

 

EDIT: --------------------------

 

 

As for P-39 - let developers do their work first. It will be easier since it is MAP-regulated.

 

Bad news, P-39L ( model in BoK ) wasn't equipped with automatic MAP regulator.

Edited January 4, 2017 by Farky

[Venturi]

Well, great. Let's see how the P39 goes..

[ACG_KaiLae]

Probably better if someone gets the Bell docs while they are there so 1CG have good info to begin their research from?

[Holtzauge]

Quote it all you want.  

 

 

 

 

 

Probably why the RAE whined so much when the NACA said the Spitfire Clmax was so much lower than the RAE "measurement", LMAO!!

 

 

Well the NACA Clmax figure of 1.15 actually supports what I’m saying and I’m surprised you got this so wrong given how prone you are to delivering lectures: When the RAE became aware of the NACA test, they wrote a technical note on it (TN 1106). In this they in classical British understatement tradition commented that the Clmax measured by the NACA “appear to be unduly low” and that the NACA’s conclusion that the excellent stall warning is obtained at the expense of a high maximum lift coefficient “is not borne out by the Royal Aircraft Establishment measurement”. The RAE measurement they refer to was the 1.36 value measured with a trailing static head and in the note they also explain the reason for the deviation: NACA had used a plane flying in formation to calibrate and as the famous British aerodynamicist M. B. Morgan notes “as a method of measuring stalling speeds this is thought to be unreliable”. Also noteworthy in TN 1106 is this statement by Morgan: “The only reliable method of obtaining Clmax in flight is by use of a swivelling pitot and a trailing static head. It is admittedly awkward but has been done successfully on the Spitfire, Me 109, Whirlwind and Buffalo.”

 

Frankly, I don’t understand why you are so obsessed with trashing the trailing pitot system and keep posting all those red underlined snippets? In addition who are you to refer to the Royal Aircraft Establishment as "whining" and make a blanket statement that they could not reliably measure airspeed in the 40’s when a professional like Morgan says the opposite? Do you really think anyone will take a self proclaimed experts googled cherry pickings seriously when they are contradicted by a respected aerodynamicist who was later knighted for his service to the crown?

 

So please stop posting all this nonsense and let’s see what the archives turn up when it comes to P-40 stall measurements and not dismiss anything out of hand shall we?

 

LMAO!! indeed. Only perhaps not in the way you envisioned Crump.........

Edited January 4, 2017 by Holtzauge

[Kurfurst]

Do you really think anyone will take a self proclaimed experts googled cherry pickings seriously when they are contradicted by a respected aerodynamicist who was later knighted for his service to the crown?

 

Does this also apply for homegrown charts of questionable provenance for aircraft performance picked over dismissed real life tests performed by the finest engineers and test pilots of their time?

[MiloMorai]

Does this also apply for homegrown charts of questionable provenance for aircraft performance picked over dismissed real life tests performed by the finest engineers and test pilots of their time?

 

Like your homegrown charts ?

[JtD]

Would it be possible to stay focussed on the P-40? It would be a shame if the topic got closed before the issues are.

 

In case of doubt, the ignore function is your friend.

[Holtzauge]

I agree completely: I think it would be good to see ANY new info on the P-40 slow speed characteristics irrespective of HOW it was measured. Once we have that we can THEN judge the validity.  Let's not discount any data beforehand based on preconceptions about what they could and could not do back then.

[DD_Arthur]

Would it be possible to stay focussed on the P-40? It would be a shame if the topic got closed before the issues are.

 

In case of doubt, the ignore function is your friend.

 

+1.  This has been an interesting thread.  

[ACG_KaiLae]

Would it be possible to stay focussed on the P-40? It would be a shame if the topic got closed before the issues are.

 

In case of doubt, the ignore function is your friend.

I'd also be annoyed to open a new one. At any rate, again, I believe we are at an impasse until Crump gets the Curtiss-Wright documentation. And, once again, thank you Crump.

[Venturi]

If any one is nearby, this location should also contain archival Curtiss-Wright documents relevant to the P-40:

 

 

Buffalo History Museum 
Research Library

Buffalo, NY 14216 United States

Edited January 5, 2017 by Venturi

[Farky]

Well, great. Let's see how the P39 goes..

 

We'll see. And Battle of Midway will be very interesting also, because non of the US aircraft there was equipped with a automatic MAP regulator.

 

--------------

 

Weight of P-40E - as I wrote, there wasn't a standard load. I do not have time and energy today for debate about weight of P-40, sorry. I will come back to this topic later if you want. Just few things - weight sheet in USAAF manual TO 01-25CF-1 issued April 25, 1941 and revised 9-5-1941 is calculated and is little bit optimistic (and very likely without self-sealing tanks). For example take a look here for the actual weight - http://www.wwiiaircraftperformance.org/P-40/P-40E_40-384_PHQ-M-19-1300-A.pdf (8011 lbs without ammo) or here http://www.wwiiaircraftperformance.org/P-40/P-40E_40-633_FS-M-19-1580-A.pdf (8035 lbs without ammo). Pretty close to Boscombe Down numbers.

 

Crump can grab some documents about weight in NASM of course (If I remember well, some weight checks of production airplanes are there). But I think it would be a waste of time.

 

------------------

 

 

Probably better if someone gets the Bell docs while they are there so 1CG have good info to begin their research from?

 

Why do you think they do not have good information? They decided to make the P-39, so I assume that they know what they're doing.

 

Obviously, the more informations the better. But frankly, we pay for the game so they have the resources to get informations from the archives by themselves. They also do not share the documents with us (which of course is absolutely fine).

[Venturi]

If true than we are still looking at 8500lbs and clean sea level stall speed of 86-90mph TAS.

OK, perhaps. If that is the case, (aug 1941 is still pre war for the US) and they were stall testing at 20-30% "non-overload tank" fuel state - IE maybe 30gals left - that would also put them at 8000lbs with the above clean stall speed. But then I rather doubt that - no proof as of yet that was the case.

We'll see. And Battle of Midway will be very interesting also, because non of the US aircraft there was equipped with a automatic MAP regulator.

 

Well,, I hope they can figure out how a non-regulated supercharger works. I think they could, they just need to understand that boost is unregulated... and they need a better engine model...

[Sgt_Joch]

more info, source is "Black Cross Red Star", vol. 2, p.57. 

 

Pilot comments from both a Soviet ace who flew the type and a German ace who flew against them that a P40 could out turn a 109.

 

 

 

[Kurfurst]

I agree completely: I think it would be good to see ANY new info on the P-40 slow speed characteristics irrespective of HOW it was measured. Once we have that we can THEN judge the validity.  Let's not discount any data beforehand based on preconceptions about what they could and could not do back then.

 

Well then. Can you provide ANY new info on the P-40 slow speed characteristics by a respected aerodynamicist?

 

This is Nikolai Golodnikov, flew P-40 with 2nd GvSAP.

 

We completely abandoned the defensive circle as soon as they re-equipped us with the P-40. The P-40 was equal to the Bf-109F and therefore we had no reason to resort to the defensive circle. No reason at all.

 

The Tomahawk and Kittyhawk had different armaments. The Tomahawk had four machine guns—two synchronized heavy machine guns in the nose and a pair in each wing. I have already forgotten the caliber of the wing-mounted machine guns, because we immediately removed them. Perhaps they were standard [they were .30 caliber—JG].

The Kittyhawk did not have [nose-mounted] synchronized machine guns. It had only six (three in each) wing-mounted heavy machine guns. We removed two of these machine guns immediately, leaving four.

 

Even during the war I recognized the fact that the Allies considered it inadvisable and almost impossible to conduct aerial combat in the P-40. We considered the P-40 to be a full-fledged fighter plane.

When we began to use the P-40, we immediately discovered two deficiencies that reduced its value as a fighter. 1. The P-40 was a “slug” in acceleration, rather slow to acquire speed. This weak dynamic resulted in a low combat speed. It had trouble maintaining the speed required for combat. Speed is essential for a fighter. 2. It was weak in the vertical, especially the Tomahawk.

We compensated for poor acceleration by holding the engine at higher revolutions and cruising at a higher speed. We corrected the second deficiency by removing a pair of machine guns. That was all. The fighter came up to par.

Now everything depended on you, the pilot. Keep your head! And work the stick intensively.

It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced.

 

 

Soviet figures for P-40 turn times, 1000m.

 

P-40C 18 secs

P-40E 19,2 secs

Edited January 6, 2017 by VO101Kurfurst

[Sgt_Joch]

I have been doing my own tests, P40 vs 109 F2, 1000 meters altitude, 50% fuel.

 

with combat power, the 109F2 is about 30 kmh faster than the P40:

 

 

 

Time to do a 360 degree turn at 1000 meters is about the same for both, 18-19 secs. Turn radius and speed loss is comparable also.

 

The relative performance seems to match the available flight tests, hard to say what if anything is wrong.

 

The real issue IMHO, is the same one we have with the 109 engine, i.e. whether the engine time limits are too strict.

Edited January 6, 2017 by Sgt_Joch

[Willy__]

I have been doing my own tests, P40 vs 109 F2, 1000 meters altitude, 50% fuel.

 

Try to do all the tests on the autumn map. All planes are [much] faster on the winter ones.   

Edited January 6, 2017 by JAGER_Staiger

[303_Kwiatek]

I have been doing my own tests, P40 vs 109 F2, 1000 meters altitude, 50% fuel.

 

with combat power, the 109F2 is about 30 kmh faster than the P40:

 

109_combat.jpg

 

P40_combat.jpg

 

Time to do a 360 degree turn at 1000 meters is about the same for both, 18-19 secs. Turn radius and speed loss is comparable also.

 

The relative performance seems to match the available flight tests, hard to say what if anything is wrong.

 

The real issue IMHO, is the same one we have with the 109 engine, i.e. whether the engine time limits are too strict.

 

If it would be for autum map it would be ok comparing to RL data. I wonder also about F-2 casue from game data it got much worse turn time then even G-2 where F-2 should be similar to F-4.

[Sgt_Joch]

I did the same tests on the Automn map and added the E7. i.e., combat power, 50% fuel, 1000 meters altitude, autolevel on.

 

speeds are slower, but relative performance stays the same.

 

The F2 is about 30 kmh faster than the P40E;

 

The P40E is about 45 kmh faster than the E7.

 

 

 

 

 

[Sgt_Joch]

I have been flying QMBs against AI 109, it is possible to outfight them in a P40, but it requires more planning, maneuvering and luck than in a Yak.

 

However, the key to the P40s historical reputation was not 1-vs-1 performance, but use of tactics that its superior radio equipment allowed:

Therefore despite its deficiencies in speed and maneuverability, its sluggishness even in climbs (in this basic characteristic it fell behind the Bf-109, Yaks, and LaGGs), in the hands of experienced aerial warriors this aircraft turned out to be a threatening weapon. A special set of "group tactics" was developed for its use, in which an insufficiency of aircraft was compensated for by good coordination within flights and echelonment by altitude [8]. Therefore a majority of the victories in the 126th IAP were group victories: HSU S. G. Ridnyy (AN965)-9 personal plus 17 in group; HSU V. G. Kamenshchikov-7 + 10; and regiment commander V. M. Naydenko-5 + 11 [9]. Twelve pilots became aces (five or more victories), and 31 pilots of the regiment were awarded orders and medals for the battle for Moscow.

http://lend-lease.airforce.ru/english/articles/romanenko/p-40/

 

The article does not go into detail, but it is an established fighter tactic. There are many variations, but basically, you have a leading element, 1-2 AC at a low altitude, followed by a cover element some distance back and at a higher altitude, far enough away not to be spotted, but close enough to intervene rapidly. If German fighters take the bait and attack the leading element, the cover element will dive down and attack them from the rear.

 

The "Flying Tigers" used the same tactics against the Japanese and Pokryshkin developed it further over the Kuban:

Pokryshkin's innovative tactics of using different fighter types stacked in altitude, the so-called 'pendulum' flight pattern for patrolling the airspace, and the use of ground-based radar, forward based controllers and an advanced central ground control system led to the first great Soviet Air Force victory over the Luftwaffe.

https://en.wikipedia.org/wiki/Alexander_Pokryshkin

 

That type of tactic works well if all ACs have good reliable radio equipment to maintain SA and coordinate their actions, so ideally suited for P40s and P39s. It would not work well with early Soviet fighters which either did not have any radio or only had a radio receiver. Unfortunately, that is not reflected at all in the sim where everyone can have perfect communication through Teamspeak.

Edited January 7, 2017 by Sgt_Joch

[Sgt_Joch]

another test, P40, 3000 RPM, 56 inch manifold pressure, 1000 meters, 50% fuel.

 

I turned off engine damage to see what it could do. As you can see below, playing with the radiators to prevent a overheat, it gets close to 555 KMH or almost 60 kmh faster than a 109F2 in combat power.

 

Obviously, allowing a 56" WEP with a 5 minute time limit, as some have suggested makes no sense IMHO since the P40 would be a lot faster than the best 109 in 1941-early 42.

 

According to all historical accounts, the P40 was slower in combat than a 109F.

 

 

 

 

Edited January 7, 2017 by Sgt_Joch

[Farky]

Well,, I hope they can figure out how a non-regulated supercharger works. I think they could, they just need to understand that boost is unregulated...

 

I believe that developers know how it works, V-1710-39 in game seems ok regarding the MAP regulation. But I'll check this again, since I am not 100% sure.

[ACG_KaiLae]

Why do you think they do not have good information? They decided to make the P-39, so I assume that they know what they're doing.

 

Obviously, the more informations the better. But frankly, we pay for the game so they have the resources to get informations from the archives by themselves. They also do not share the documents with us (which of course is absolutely fine).

 

 

I assume a mostly Russian based development team might have easiest access to Russian documents. I also doubt that they have someone that they can just send over to the smithsonian. It's not that I doubt their competence, but more stuff is better. If they already have them great, if not, well, then they do and better results possibly.

[Farky]

I assume a mostly Russian based development team might have easiest access to Russian documents. I also doubt that they have someone that they can just send over to the smithsonian. It's not that I doubt their competence, but more stuff is better. If they already have them great, if not, well, then they do and better results possibly.

 

Come on, in 21st century you don't need send someone to the other end of the world for some papers. Most archives will send you an electronic copy of documents you want, personal experience. Only things you need to get archival documents in 2017 are basically PC with internet access and credit card. It's much faster and cheaper (if you live nearby) go there in person of course.

 

I get your "more stuff is better" point, but if developers think they have enough informations, why waste time. They know best what they need. If they do not have enough informations, they can ask the community for help. They may even look for specific information and ask if someone has this info, they did this before. But it is their job to get the adequate documentation for the game developement.

 

 

[Venturi]

I believe that developers know how it works, V-1710-39 in game seems ok regarding the MAP regulation. But I'll check this again, since I am not 100% sure.

Just going off dev numbers. The gauge tells no truths since it stops at 50"

[Sgt_Joch]

so after looking through the in game specs, I ran some more tests and as I suspected, the Allison performs better at altitude. Again tests are at combat power, 50% fuel, auto level on, Moscow winter map.

 

As you can see, the P40 and 109F2 have exactly the same speed at 4000 and 5000 meters.

 

The P40 can no longer maintain a 42 inch boost above 4500 meters because of its single stage supercharger while the 109F2 can maintain 1.25 ata until above 5500 meters.

 

so the sweet spot to enter combat is between 4000 and 5000 meters.

 

 

 

 

 

 

 

 

 

 

 

p.s. - tips to combat the 109F2:

 

-merge between 4-5000 meters;

 

-do not do a climbing turn. P40 acceleration/climb rate is too poor;

 

-do a diving turn so you can pick up speed/energy  ( i.e. a " Low Yo-Yo" maneuver). Watch the MP gauge and maintain 42" boost or less while diving;

 

-use flaps as required (10-15%) to maintain low speed turn radius. Make sure to "step on the ball", the P40 will stall out at low speed if side slipping;

 

-once you are on the 109s tail, it is easy to stay there, unless he extends away.

Edited January 8, 2017 by Sgt_Joch

[Crump]

Well the NACA Clmax figure of 1.15 actually supports what I’m saying and I’m surprised you got this so wrong given how prone you are to delivering lectures: When the RAE became aware of the NACA test, they wrote a technical note on it (TN 1106). In this they in classical British understatement tradition commented that the Clmax measured by the NACA “appear to be unduly low” and that the NACA’s conclusion that the excellent stall warning is obtained at the expense of a high maximum lift coefficient “is not borne out by the Royal Aircraft Establishment measurement”. The RAE measurement they refer to was the 1.36 value measured with a trailing static head and in the note they also explain the reason for the deviation: NACA had used a plane flying in formation to calibrate and as the famous British aerodynamicist M. B. Morgan notes “as a method of measuring stalling speeds this is thought to be unreliable”. Also noteworthy in TN 1106 is this statement by Morgan: “The only reliable method of obtaining Clmax in flight is by use of a swivelling pitot and a trailing static head. It is admittedly awkward but has been done successfully on the Spitfire, Me 109, Whirlwind and Buffalo.”

 

Frankly, I don’t understand why you are so obsessed with trashing the trailing pitot system and keep posting all those red underlined snippets? In addition who are you to refer to the Royal Aircraft Establishment as "whining" and make a blanket statement that they could not reliably measure airspeed in the 40’s when a professional like Morgan says the opposite? Do you really think anyone will take a self proclaimed experts googled cherry pickings seriously when they are contradicted by a respected aerodynamicist who was later knighted for his service to the crown?

 

So please stop posting all this nonsense and let’s see what the archives turn up when it comes to P-40 stall measurements and not dismiss anything out of hand shall we?

 

LMAO!! indeed. Only perhaps not in the way you envisioned Crump.........

 

 

So we can say that in your opinion, only Supermarine could reach their design CLmax.  Grumman, Messerschmitt, Curtiss, Focke Wulf, and everyone else are completely suspect or unable to do what you claim Supermarine did....achieve their design coefficients of lift.

 

You do know being able to do that is a fundamental requirement of aeronautical engineering.

[unreasonable]

So what was the Spitfire CLmax? 1.36?

 

The wing was 2213-2206.

 

NACA gives 2212 CLmax as 1.60, 2213 can hardly have been more than 0.01 - 0.02 different

 

If 1.36 was the design CLmax interesting that it is almost 0.24 less that the airfoil.

[Holtzauge]

 

Well the NACA Clmax figure of 1.15 actually supports what I’m saying and I’m surprised you got this so wrong given how prone you are to delivering lectures: When the RAE became aware of the NACA test, they wrote a technical note on it (TN 1106). In this they in classical British understatement tradition commented that the Clmax measured by the NACA “appear to be unduly low” and that the NACA’s conclusion that the excellent stall warning is obtained at the expense of a high maximum lift coefficient “is not borne out by the Royal Aircraft Establishment measurement”. The RAE measurement they refer to was the 1.36 value measured with a trailing static head and in the note they also explain the reason for the deviation: NACA had used a plane flying in formation to calibrate and as the famous British aerodynamicist M. B. Morgan notes “as a method of measuring stalling speeds this is thought to be unreliable”. Also noteworthy in TN 1106 is this statement by Morgan: “The only reliable method of obtaining Clmax in flight is by use of a swivelling pitot and a trailing static head. It is admittedly awkward but has been done successfully on the Spitfire, Me 109, Whirlwind and Buffalo.”

 

Frankly, I don’t understand why you are so obsessed with trashing the trailing pitot system and keep posting all those red underlined snippets? In addition who are you to refer to the Royal Aircraft Establishment as "whining" and make a blanket statement that they could not reliably measure airspeed in the 40’s when a professional like Morgan says the opposite? Do you really think anyone will take a self proclaimed experts googled cherry pickings seriously when they are contradicted by a respected aerodynamicist who was later knighted for his service to the crown?

 

So please stop posting all this nonsense and let’s see what the archives turn up when it comes to P-40 stall measurements and not dismiss anything out of hand shall we?

 

LMAO!! indeed. Only perhaps not in the way you envisioned Crump.........

So we can say that in your opinion, only Supermarine could reach their design CLmax.  Grumman, Messerschmitt, Curtiss, Focke Wulf, and everyone else are completely suspect or unable to do what you claim Supermarine did....achieve their design coefficients of lift.

 

You do know being able to do that is a fundamental requirement of aeronautical engineering.

 

 

This is has to be a new world record in straw man construction: I have said NOTHING of the kind! How on earth can you misinterpret and misrepresent what I wrote and make it out like I said that? Its simply absurd!

[Crump]

That is what your saying....

 

It is not a strawman Hotzauge.  Nobody is "against" you.  Just trying to figure out your logic is all.

[ZachariasX]

Yes, here

http://www.dtic.mil/dtic/tr/fulltext/u2/a801175.pdf

see page 10,

 

they give the 2212 a Clmax of 1.6 at a R.N.:3.220.000. At least that is what I can make of the graph.

 

It's old stuff, measured in 1931...

[Crump]

So what was the Spitfire CLmax? 1.36?

 

The wing was 2213-2206.

 

NACA gives 2212 CLmax as 1.60, 2213 can hardly have been more than 0.01 - 0.02 different

 

If 1.36 was the design CLmax interesting that it is almost 0.24 less that the airfoil.

 

I do not know where Holtzauge gets the 1.36.  In looking at RAE documents, I have found the Clmax as high as 1.82 for power on effects in a turn.

 

That is what I am trying to find out.

 

I agree that the design Clmax for the Spitfire is ~1.6.  

 

You can see that in the POH numbers:

 

Weight 7150lbs 

Stall Speed = 78KIAS

 

PEC = + 3.4Kts

 

Normal wings = -5.2Kts

 

76 knots....

 

Well it requires 74 knots to equal a Clmax of 1.59 which well within the 3% margin of error for level speed measurement and agrees with engineering convention by meeting the NACA 2213 measured airfoil characteristics.

Yes, here

http://www.dtic.mil/dtic/tr/fulltext/u2/a801175.pdf

see page 10,

 

they give the 2212 a Clmax of 1.6 at a R.N.:3.220.000. At least that is what I can make of the graph.

 

It's old stuff, measured in 1931...

 

 

That is not really the same airfoil but it is close.

Edited January 8, 2017 by Crump

[Holtzauge]

I do not know where Holtzauge gets the 1.36.  In looking at RAE documents, I have found the Clmax as high as 1.82 for power on effects in a turn.

 

Yes 1.82 is with power on. The 1.36 is with power off. This is kind of basic Crump and something you learn rather early on in aerodynamics classes. I'm sure if you google it you can find some more info. Try also googling slipstream effects. That should point you in the right direction.

[Holtzauge]

That is what your saying....

 

It is not a strawman Hotzauge.  Nobody is "against" you.  Just trying to figure out your logic is all.

 

Priceless!