Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: HoHun on July 11, 2004, 03:33:37 AM
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Hi everyone,
I just found some information relevant to the topic below which I took from a recent monster thread (http://www.hitechcreations.com/forums/showthread.php?postid=1229708&highlight=pressure+spitfire+altitude#post1229708).
From Duncan Smith, "Spitfire into Battle":
"One of the greatest thrills was having twelve Spitfire Mk IXs in battle formation at 43,000 ft in the knowledge that no German fighter could touch us."
(You might have seen that quote before.)
"In fact, the limiting factor rested in the flying equipment available to do the job because existing oxygen and ventilation sytems could no longer be considered entirely efficient to meet the exacting conditions. Without pressurisation at such great altitudes, the physical discomfort from fatigue and pain from 'bends' limited the flight-time we could endure to barely five minutes or so."
(Two paragraphs down from the first quote. I think this highlights nicely why the race for altitude was finally abandoned!)
Regards,
Henning (HoHun)
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Hi Angus,
>Oh, and HoHun, you're right. Spitfire IX with a Merlin 61, my mistake calling it a HF.
>It is good at high altitude none the less.....
Roger that! I'd say it represented the peak of the race for altitude :-) For some reasons, that race was abandoned shortly after the introduction of the (Merlin 61) Spitfire IX. The Luftwaffe had geared up for production of the Fw 190B, which would have been the high-altitude Focke-Wulf with suprisingly good performance up high, but canceled it right before it was to go on the production lines. Subsequent Spitfires got engines designed for lower altitudes, and the P-51 swapped its high-altitude Merlin for a medium-altitude one, too.
I'm not sure what the reasons were for this paradigm change - it might be that stratospheric flight without pressure cabins was fairly dangerous in itself, even before you ever met an enemy up there.
Regards,
Henning (HoHun)
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Hello
Nice.
I once talked with a pilot who took a Spitty up to 49000 feet. I asked him if it had been uncomfortable, and he said "not really"
Getting to 49K he would have exceeded those 5 minutes by far in the alt bands above say 35K.
The cold peaks before 30K he said, and as a sidepoint, he found it to be colder in the high alt bands over the med than i.e. over Britain.
I do recall some pilots mentioning it being painful to keep flying that high, joints started aching etc.
This particular pilot mostly hated long escort missions (P51) cruising at 30K+ for hours (5 hours or so I think), those were the really cold arse missions he said. The ride was P51.
A Spitty would never be up that high that long, so I wonder how it worked.
The human body does not instantly submit to lowering pressure, it comes a bit gradually, as you'll know, your legs will swell more on longer flights etc.
Also, I wonder what being arse cold did as an effect, well, it slows down your bloodstream (veins schrinking) but that again slows the effect of low pressure.
Anyway, there is another factor with the super high flying that has not been mentioned yet.
The aircraft were not that tight, and going viciously between alt bands woud "Ice" the whole interior, the windscreen included.
Surprizingly, many aircraft never had a cure for this, - Gunther Rall mentions scraping Ice in his 1944 model 109G.
Some Spits had a cure in the form of a little tube from the outside to the windscreen, keeping it free, but those were field mods (1942 onwards). I wonder about the US planes. At least they incorporated electrically heated suits for high flying and some more gadgets.
Anyway, would be nice to know more.
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Angus,
From what I know, in order to reach extreme altitude in an unpressurized environment you have to pre-breath 100 percent oxygen at sea level.
It is kind of like SCUBA diving in reverse. By breathing the O2 at the higher pressure of Sea Level your body off gasses Nitrogen. There is a table very similar to Dive tables in that it gives the amount of time you must breath O2 at sea level to reach the target altitude. It includes a time limit at which you can stay at that altitude.
Cold makes you more susceptible to decompression sickness.
Crumpp
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Hi Angus,
>I once talked with a pilot who took a Spitty up to 49000 feet. I asked him if it had been uncomfortable, and he said "not really"
Hm, that's 15 km. Are you sure he had no pressure cabin or at least a pressure suit?
http://www.dfrc.nasa.gov/Research/AirSci/ER-2/pshis.html
http://www.astronautix.com/craft/wiltsuit.htm
>The human body does not instantly submit to lowering pressure, it comes a bit gradually, as you'll know, your legs will swell more on longer flights etc.
I think there's a lot of variation between individuals and even for the same individual depending on the varying level of fitness and adjustment. The 5 min certainly aren't edged in stone, but if you wouldn't need pressure cabins, why was so much effort put into them?
I found the following article quite interesting:
http://www.avweb.com/news/columns/182156-1.html
Just as airmen of WW1 ignored the dangers of high altitude flying when they went up without oxygen, WW2 pilots climbed beyond safe altitudes, too. To a certain degree, it paid off because it gives you the altitude advantage, but cruising routinely at unsafe altitudes can add to operational attrition exceeding the tactial advantages. It's my impression that this point might have been reached in 1942, reversing the trend towards ever higher altitudes.
>The aircraft were not that tight, and going viciously between alt bands woud "Ice" the whole interior, the windscreen included.
The windscreen was actually affected worse, because it was a big block of armour glass that wouldn't adjust its temperature quickly. I think this problem was shared by all contemporary aircraft as I've also found it mentioned for US planes. A fresh air tube could mellow the symptoms, but not entirely prevent it either. (From what I've read, British test pilots liked the effective Me 109E ventilation, but of course without a sliding hood, it better should be effective :-)
>At least they incorporated electrically heated suits for high flying and some more gadgets.
I think the Luftwaffe had these, too, including electrically heated gloves which made operating the cockpit switches much easier. Eric Brown thought these compared favourably to the fur-lined British gloves "guaranteed to turn your fingers into a bunch of bananas".
As far as I know, heated suits were standard equipment with Bomber Command, too. I seem to recall that one crew member had a malfunction of the regulator and was left with the choice between frost bite and burns, eventually suffering the latter despite his attempts to adjust the temperature by cycling the suit between on and off all the time. (I'm not entirely sure on the RAF bit, though, it might have been the story of a USAAF crewman after all.)
>Anyway, would be nice to know more.
Yes, fascinating topic only seldom mentioned in the books! :-)
Regards,
Henning (HoHun)
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I'm guessing it was probably a spit VII that got to 49,000ft (pressurised cabin).
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Hi again,
Another interesting article from Deakin:
http://www.avweb.com/news/columns/182123-1.html
Have a look at the GLOC paragraph.
Regards,
Henning (HoHun)
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Nice links.
Got to give me some time for reading here.
For the 49K Spit, my memory sais IX, but I'll have to get to log books to verify. I am pretty sure it was not a pressurized cabin though.
That pilot flew Mustangs on longe range escorts to Berlin,- for the RAF, - P51C. They never got anything electrically heated and were basically freezing their butt off on those missions. He mentioned that they were always being promized heated gloves and suits etc, but never got any, unlike the Americans.
About that Oxygen status, I am a bit confused.
13K is often stated as a DO NOT GO HIGHER WITHOUT OXYGEN alt.
Well, once upon a time I climbed up to 12K and cruised there for an hour or so without noticing a thing. (Cessna 172). So, definately not chopped in stone I must say.
And I live at the humble elevation of 60 feet..........
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Yep,
The reason you prebreath is to prevent decompression sickness not Hypoxia.
About that Oxygen status, I am a bit confused.
The USAAF says 12,500 feet is the O2 cut off. Above that you must me on Oxygen. This is because the symptoms of Hypoxia can be insidious.
It is similar to Nitrogen Narcosis when SCUBA diving. I used to have students taking a Deep Diving Specialty do math problems at the surface and time them. We would then go to 130 FSW and do the same problems. On average it would take 5 times as long for them to do the math at that depth. Many of them would swear they felt nothing but the stopwatch told the real story.
Crumpp
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The generally accepted highest combat in WW2 was the interception of a JU86R over England by a specially modified Spitfire IX flown by Emanual Galitzine. where he managed to get to 44,000 feet. Galitzine wore an electrically heated suit btw.
I don't believe that the 49K story is accurate as I don't know of any Spits that got up that high, pressurized VIIs or not. The absolute ceiling on a Spit VII is 45,700 with the service ceiling 45,100.
Needless to say the physiological affects on pilots in unpressurized cockpits at those high alts was extreme.
There were some locally modifed Spit Vs in the Med used to chase JU86Ps and those pilots really struggled, and they didn't reach those altitudes as the single stage Merlins just couldn't do it, although they did manage to stop the Ju86P sorties. This of course led to the R model which could get to 45K
I'm a Spit fanatic, and have even had the pleasure of corresponding with and meeting Galitzine a number of years back, but that being said, I don't believe any Spits made 49K
Dan/Slack
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The high altitude performance competion was at altitudes where the high altitude bombers (B-17 around 30k) and reconaisance planes flew (Mosquitos, PR Spitfires etc. again something around 25-30k). Generally pilots were not asked if it was comfortable to fly at high altitude; the task was up there so they flew there. Some planes had pressuriced cabins, most not.
The next Merlin used in the Spitfires after the Merlin 61 was the Merlin 63 (reached service at spring 1943) which offered about same high altitude performance as the Merlin 61. Later HF Spitfires got the Merlin 70 which offered actually better high altitude performance than the Merlin 61 or 63. And some amount of HF Spitfires were produced alongside LF variants until the end of the conflict.
The Fw 190B was basicly the Fw 190A with the GM-1, seems that one of the prototypes had a larger wing but otherwise the Fw 190B offered quite little imrovement over the Fw 190A at high altitude and the Bf 109G with GM-1 did better so the was not much reason to produce Fw 190B. The developement of the Fw 190 (with BMW 801) was going towards multipurpose fighter use and high altitude developements were continued under designation Ta 152 from late 1942 onwards (which all featured new larger wings as well as other engines). The Fw 190D was, according to Kurt Tank himself, a stop gap solution until the Ta 152 reached production and actually late Fw 190D variants were multipurpose planes again.The only real high high altitude version of the BMW 801 to reach limited service was 801J of the Ju 388, otherwise the high altitude performance of the BMW 801 was quite limited even with the GM-1.
The Germans or Focke Wulf never abanoded race for high altitude performance, they were just unable to field their high altitude piston engine developements; the Ta 152H was too little too late, most other piston engined high altitude developements were failures.
Regarding the change from the V-1650-3 to V-1650-7 in the P-51. This was decided at autumn 1943 because USAAF had allocated all P-51Bs to tactical fighter use and RAF also wanted medium and low altitude performance. All P-51 developements after the P-51D (P-51F, P-51H etc.) featured high altitude engines and actually some late P-51Ds got V-1650-9 too. Still even with V-1650-7, the P-51 did better than most german fighters at high altitude.
gripen
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Gripen, if the P-51B was assignd to the tactical role, then why was there still Bs flying deep into Germany with the 'heavies', a year later?
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Originally posted by MiloMorai
Gripen, if the P-51B was assignd to the tactical role, then why was there still Bs flying deep into Germany with the 'heavies', a year later?
The whole story can be found from the "P-51Mustang: Developement of the Long-Range Escort Fighter" by Paul A. Ludwig. The first unit in the ETO to receive the P-51B was the 354th FG of the 9th AF, the second unit to receive it was 357th FG of the 9th AF. The Mustangs were allocated for 9th AF (ie a tactical AF) but the crisis in the day light offensive late 1943 forced USAAF to think again and so these units were assigned for escort task with known results. Basicly USAAF had allocated it's best high altitude fighter for tactical purposes.
gripen
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Originally posted by gripen
Basicly USAAF had allocated it's best high altitude fighter for tactical purposes.
gripen
Well, many would argue that the P-47 was the AAF's best high altitude fighter. However, it lacked the range to be its best escort fighter. That role belonged to the P-51. You are correct that the AAF assigned the Mustangs to the 9th Tactical AF. Standard bureaucratic stupidity. It was typical of the AAF to assign by squadron availability rather than by aircraft type. Once Gen. Arnold became aware that the P-51 was the answer to deep escort needs, most Mustangs went to the 8th AF Fighter Command. By late 1944, only the one 8th AF fighter group flew anything but the P-51 (56th FG flew P-47s throughout the war). P-38s and P-47s were transferred to the 9th Tactical AF where their superior durability and load lifting capability could best be exploited.
As it was, the 8th AF managed to get the first P-51 groups placed under 8th FC control. Virtually all of the new P-51s arriving in Britain were immediately assigned to 8th AF groups. The 4th FG flew its first P-51 escort missions with some pilots having less than 10 hours of Mustang flight time. On the job training, so to speak.
The overwhelming problem faced by the Luftwaffe, beyond a shortage of trained pilots and decreasing stocks of fuel, was the fact that the 8th AF now possessed a fighter that could loiter over Luftwaffe fighter bases, effectively ending the ability to rearm and attack the bombers on their return flight. For many Luftwaffe pilots, the most dangerous portion of the mission was simply getting back down on the ground without being shot out of the landing pattern. This was an especially effective method of cancelling the advantage of the Me 262. Germany could and did disperse their fighters all over the countryside. However, this greatly impacted command and control, as well as general logistics. As the British and American Armies advanced nearer the German border, things only got worse as the shorter range fighters (Spitfires, P-47s and Typhoons) could now reach Luftwaffe fighter bases.
My regards,
Widewing
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The Germans or Focke Wulf never abanoded race for high altitude performance, they were just unable to field their high altitude piston engine developements; the Ta 152H was too little too late, most other piston engined high altitude developements were failures.
Bureaucratic infighting caused their engine developments to be failures. NOT through a lack of materials technology availability. The beliefs the Germans could not develop adequate supercharger technology or lacked high strength alloys are a myth.
Crumpp
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It's unbelieveable too that the decision was made to regulate the P51B's to a tactical role. Of all the allied fighters in service at the time the P51B was the best suited for dogfighting the FW-190A.
The Spitfire Mk IX was the performance equal of the FW-190A. It held some advantages but the FW-190 had some cards too. Each of the planes strength canceled the others weakness and pilot skill was left to decide the outcome.
The P51B had advantages in level speed, dive, and a "slight' turn advantage. Only in roll rate and climb did the FW-190 hold any cards.
The level speed advantage was commanding. 50 mph rising to 70 mph at some altitudes. This translated to a better zoom climb if the P51 was at speed also.
Crumpp
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Crumpp, then why was the 004A re-engineered to use less 'durable' metals for its turbine blades in the 004B if what you say is true? :confused:
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Originally posted by Crumpp
It's unbelieveable too that the decision was made to regulate the P51B's to a tactical role. Of all the allied fighters in service at the time the P51B was the best suited for dogfighting the FW-190A.
Crumpp
It was an unproven commodity at the time those decisions were being made. And even after the Mustang was given to the 8th AF it suffered it's share of teething troubles well into the Spring of 44., with motor mount trouble, plug troubles etc.
Clearly they saw the need for the Merlin 51 quickly as the 357th was 'traded' to the 8th AF for a P47 group that was originally designated for the 8th. And the 354th was used in the escort role while still 9th AF.
Dan/Slack
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Because they did not need it. They accomplished the same thing with easier to manufacture materials.
The Germans took on a different philosophy than the allies for developing A/C engines.
The engineering challenge was fitting an engine of size weight and capability into a tiny airframe and to ensure that power was available when needed. If you notice the LW fighters are dimensionally smaller than their allied counterparts.
Rather than concentrate on large boost pressure increases from large multistage superchargers the Germans took the approach of small manifold pressure increases with a higher compression ratio. To further increase the "on demand" power they used pwer boost systems such as MW-50, MW-30, and GM-1. Their system was very efficient for their needs and worked well. The DB-605D engine developed 2000 hp on takeoff. Easily on par with the Gryphon 65.
This myth becomes readily apparent when you consider a substantial portion of Luftwaffe fighters were manufactured using "Electron", a magnesium alloy which was lighter than aluminum. Instrument panels, wheel hubs, engine bearers, and many other components were made of electron.
This not to say the 109 was not obsolete by the last years of the war. In a trained pilots hands it was a deadly opponent. However, it had developed in some ways into an unforgiving thoroughbred which the vast majority of poorly trained late war Luftwaffe pilots could not effectively use it's advantages nor survive long enough to learn.
Crumpp
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Crumpp, then why was the 004A re-engineered to use less 'durable' metals for its turbine blades in the 004B if what you say is true?
My previous post is answer to your statement Milo.
Crumpp
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"It's unbelieveable too that the decision was made to regulate the P51B's to a tactical role."
All the earlier Mustangs were used for ground attack extensively with considerable success. That is the reputation it had at the time; that has oviously been overshadowed by subsequent events.
The early P-51B's still didn't have sufficient range anyway (no gas tank behind the cockpit yet).
The USAAF had never shown much interest in using the Mustang as a fighter.
9th Air Force was asking for more aircraft.
Without the benefit of hindsight, where would YOU have deployed them?
They made a mistake and it was soon rectified. It's an understandable mistake.
J_A_B
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Without the benefit of hindsight, where would YOU have deployed them?
USAAF conducted extensive tactical trials of the P51B against a captured 190A. The performance of the P51B as a fighter was known quantity.
Crumpp
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Yeah you mentioned that already.
My point is that I can see why the Army deployed it where they did. I never said it was a correct choice.
J_A_B
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Yeah someone must have been stuck in the "Mustang is a ground attack plane" mindset. From what I have read the mustang pilots were itching to tangle with Luftwaffe and did not relish the tactical role. Especially down low behind enemy lines in an inline engine fighter, knowing one hit to the radiator and your done.
Guess though most fighter pilots were of a similar mindset regarding any mission not purely fighter to fighter. Reminded me of Oblt. Hans Phillip Commanduer of JG 1 in October 1943.
"Against 20 Russians trying to shoot you down, or even 20 Spitfires, it can be exciting, even fun. But curve in towards 40 Fortresses and all your past sins flash before your eyes."
Crumpp
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Everest is @ 24.000 ft and more.
Hilary and many others was there without masks.
Ofcourse others had problems.
I think the best pilots for high alts @ wwii would be, heh....
Gourkas the famous warriors :)
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Originally posted by Crumpp
Yeah someone must have been stuck in the "Mustang is a ground attack plane" mindset. From what I have read the mustang pilots were itching to tangle with Luftwaffe and did not relish the tactical role. Especially down low behind enemy lines in an inline engine fighter, knowing one hit to the radiator and your done.
Guess though most fighter pilots were of a similar mindset regarding any mission not purely fighter to fighter. Reminded me of Oblt. Hans Phillip Commanduer of JG 1 in October 1943.
"Against 20 Russians trying to shoot you down, or even 20 Spitfires, it can be exciting, even fun. But curve in towards 40 Fortresses and all your past sins flash before your eyes."
Crumpp
I think you are missing the point Crumpp. You mention late 43 as when the thinking was use the 51 in a tactical role. The 354th was loaned to the 8th in December 43 for escort duties. And the 357th was 'traded' for a Jug group and the 363rd FG in 51s didn't arrive until February 44. and the 4th FG only started transitioning to the 51B in late February.
It didn't really become operational in any numbers until early 44 and during that time well into March-April it was suffering with many teething troubles with motor mounts and bad plugs, as well as needing the additional fuselage fuel tank mod done.
Also keep in mind that USAAF experience with the Mustang was in the recce/ground attack role with the Allison engined Mustangs. The A36 in particular having proven itself an effective ground attack bird in Italy.
Bottom line is as the Merlin Mustang arrived it was put in the role it was best suited for.
Dan/Slack
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Well, my point was just that the reason to change from the V-1650-3 to the V-1650-7 was that USAAF allocated the P-51 for tactical purposes and RAF also wanted low altitude performance; RR developed the Merlin 65 for the Mustang (same as the Merlin 66 but with different reduction gear ratio).
Regarding the USAAF use of the P-51B there is couple things to note. In 20th August Gen. Arnold allocated all coming P-51Bs and a bit later most of the Mustang IIIs from RAF (according to agreement between Arnold and Portal) to 8th AF. But for one reason or another at mid October Gen. Eaker deciced to give them to 9th AF. 354th and 357th FG were just loaned for escort duties due to situation from 9th AF until end of the January and 354th and 363rd FG continued in escort tasks after that despite they were still part of the 9th AF. Actual date of the official decision to use the P-51B as an escort fighter and to allocate all coming P-51B to a strategic AF was 24th January.
Despite various teething problems the P-51B did well and actually better than the P-47 or the P-38 during big week. The Only FG to perform better (in the amount of kill claims) than 354th or 357th FG during big week was the 56th FG which had been around about a year at that time and it should be also noted that the 56th was a very large group, they usually launched over 100 fighters for a mission. Another thing to note is that in March 1944 six FGs operated at least partially with the P-51B (357th, 354th, 4th, 363rd, 352nd, and 355th) and in May 1944 the 8th AF had more operational P-51s than operational P-47s.
gripen
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I think you are missing the point Crumpp. You mention late 43 as when the thinking was use the 51 in a tactical role. The 354th was loaned to the 8th in December 43 for escort duties. And the 357th was 'traded' for a Jug group and the 363rd FG in 51s didn't arrive until February 44. and the 4th FG only started transitioning to the 51B in late February.
Late 43 is when the quote was made and is not refering to the P51B. I can't find any reference in any of my post to a timeframe on the P51B.:confused:
Crumpp
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Originally posted by Crumpp
My previous post is answer to your statement Milo.
Crumpp
Let me quote from the 262 book.
"Some 6 months of very labourous work was required before a partial remedy to the vibration problem was found by substituting steel blades for the original light alloy stator blades."
"It also used many scarce heat-resistant metals such as nickel, cobalt and molybdenum in all 'hot' engine parts."
"Franz accepted that once the Jumo T1 (aka 004A) had proved that the turbojet principle was sound, his team would have to redesign it as a production engine using materials that were more readily available."
What is this Gryphon engine you mention? Do you mean the R-R Griffon engine?
Crumpp, what date for that 51B/190 comparison trial?
Gripen if the 56th launched 'over 100 fighters' then the 3 FS of the 56th would have had at least 33 a/c in each squadron. Is this the establishment of a USAAF FS? Could the 47 reach Berlin in Feb 44?
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The engine is the Gryphon 65. The one powering the Spitfire Mk IVX.
The Gloster Meteor first flew in 1943 and beat the ME262 into operational Squadron service in 1944 by three months although by the end of the war the Germans did have many more operational jet fighters than the British. The Meteor would have entered service much earlier had the British efforts not been dogged by material shortages and poor decisions in the early war years although it did arrive in time to fill a requirement for high speed aircraft to catch the V1 flying bombs (Buzz-Bomb) in a new terror campaign initiated in the last stages of the war. Only one Squadron, 616 Squadron Royal Auxiliary Air Force operated Meteors in the WWII mainly in the ground attack role as they were not allowed early on to fly too deep into enemy territory due to the secrtecy surrounding the materials used in the Derwent engine which made it much more reliable than the axial-flow turbojets of the ME262 although had they met in combat the ME262 would probably had the upper hand as it was the faster of the two aircraft in addition to being lighter although the Meteor III which reached 616 Squadron before then end of the war went some way towards addressing this deficit.
http://www.meteorflight.com/
Turbine engine technology pushed materials technology to the very limit of 40's standards. It was just the nature of the beast and not a reflection on anything particularly German.
Material Shortages were a daily fact of life in WWII even for the Allies. The United States even adopted a strict rationing policy.
Don't know the exact date on the P51B test. Alfred Price just list's it as Winter 43/44. I am looking for a copy of the actual report from the USAAF.
Crumpp
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Originally posted by Crumpp
The engine is the Gryphon 65. The one powering the Spitfire Mk IVX.
The Spitfire XIV used a Griffon engine. Rolls-Royce never had an engine named the Gryphon.
Here is a pic of the Griffon 65
(http://www.aircraftresourcecenter.com/AWA1/601-700/walk618_Griffon-engine_Chetwynd-Chatwin/01.jpg)
Notice the info board under the prop shaft
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BTW Milo,
Price does specifically say the test's were conducted before the P51B entered service in the European Theater.
Crumpp
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LOL
No wonder I had so much trouble finding any info online about the Griffon engine.
I had to look it up in printed reference material and never even noticed.
Thanks.
Crumpp
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MiloMorai,
I don't know the reason why some P-47 groups had strenght well above the normal strenght of a group which should be around 60-70 operational planes.
Regarding the range of the P-47D in February, it certainly could not reach Berlin then. Later P-47D models with larger internal fuel capacity probably had a range very close to Berlin.
gripen
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gripen, the internal fuel increased from 307 to 370 gal (US) in the D-25. Two 108gal(US) (216gal) gave an increase in range of ~150miles (according to Baugher's site).
From one of those range radius drawings, in June 43, the P-47 could reach 230 mi without external fuel. Can't see an extra 65 gal, internal, being enough. It would give more flying time after the drop tanks were dropped though.
These numbers could be 'messed up' some since the diagram gives 375mi (a 145mi increase) with a belly tank(size unknown).
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Originally posted by Crumpp
Late 43 is when the quote was made and is not refering to the P51B. I can't find any reference in any of my post to a timeframe on the P51B.:confused:
Crumpp
Yep you are right. Your initial response was to gripen's post about the 51B in late 43. I tied it to that. My mistake.
In regard's to the test against the 190. I wonder if in fact it was one of the 5 Rolls Royce modified P51 Mustang X's with the Merlin 65 that was used and not a standard P51B?
Dan/Slack
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MiloMorai,
Depending on source, late P-47D models (370 gal. internallly) appear to have combat radius around 475 miles with drop tanks ( 2x 108 gal.) and Berlin is about 500 miles from East Anglia. AHT gives combat radius with 150 gal. drop tanks but I don't know if these were used in ETO.
gripen
edit: Corrected tank size
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Originally posted by gripen
MiloMorai,
Depending on source, late P-47D models (370 gal. internallly) appear to have combat radius around 475 miles with drop tanks ( 2x 108 gal.) and Berlin is about 500 miles from East Anglia. AHT gives combat radius with 150 gal. drop tanks but I don't know if these were used in ETO.
gripen
edit: Corrected tank size
If you look at the photo evidence, you'll be hard pressed to find photos of operational ETO based P47s carrying two 108 gallon tanks. The earliest I can find an image is of a 9th AF P47 post D-Day with two 108 gallong tanks. There was also 1 photo of 78th FG Jugs in mid summer 44 with two 108s and a 150 on the centerline for a long range ramrod mision, and one other of 2 56th FG P47Ms late in the war with two 108 gallon tanks.
In general you'll see single 108 gallon tanks on the centerline or the later flatter 150 gallon single tank on the centerline. I'm not sure why this is the case.
Prior to May 44 the Mustangs were lugging 75 gallon metal drop tanks, before getting the paper 108 gallon tanks in May. Later there were 110 gallon metal tanks too.
OK found one more photo of a razorback Jug with 3 108 gallon tanks from the 353rd FG. It was in the Warren Bodie book on the Jug. He states that even with these three tanks, the Jug could not escort to Berlin and back, but that the extra 324 gallons of fuel nearly doubled the range of the Jug.
Scan is of that Jug, ID'd as a P47D-15RE.
Dan/Slack
(http://www.onpoi.net/ah/pics/users/169_1089754714_3tankjug.jpg)
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Darn Guppy!
You may have solved one big question I had. On the NACA roll rate report it lists an XP-51. As late in the war as these test's where conducted that makes NO sense. The prototype P51 was tested back in early 1940 or 1941. Way too early to be applicable to the NACA test. It would have been EASY to get a P51B, C, or possibly even a D for their test purposes.
HOWEVER, a Mustang X fits the NACA test perfectly for the time frame and would explain the descrepancy between that test and the tactical trials conducted in England with a P51B.
According to the NACA test a Mustang X could roll with a 190 at speeds around 390 mph IAS. According to the USAAF test's in England on the P51B the FW-190 outrolled the P51B at all speeds.
Crumpp
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Originally posted by Crumpp
Darn Guppy!
You may have solved one big question I had. On the NACA roll rate report it lists an XP-51. As late in the war as these test's where conducted that makes NO sense. The prototype P51 was tested back in early 1940 or 1941. Way too early to be applicable to the NACA test. It would have been EASY to get a P51B, C, or possibly even a D for their test purposes.
HOWEVER, a Mustang X fits the NACA test perfectly for the time frame and would explain the descrepancy between that test and the tactical trials conducted in England with a P51B.
According to the NACA test a Mustang X could roll with a 190 at speeds around 390 mph IAS. According to the USAAF test's in England on the P51B the FW-190 outrolled the P51B at all speeds.
Crumpp
Probably adding to the confusion.
First image is of the first Mustang X modified by Rolls Royce with the Merlin 61 and first flown on October 13, 1942.
Second image is of the first North American built XP51B first flown on November 30, 1942.
I'm guessing you are stil looking at one of the XP51Bs for that testing.
The 4th and 5th Rolls Royce built Mustang Xs were sent to Duxford for evaluation by the USAAF however in January and February of 43. I've seen a couple photos of one of them in USAAF markings as well.
I wonder if the USAAF tests in England were with the Mustang X that did not have the more streamlined nose and radiators while the NACA tests were with one of the XP51Bs?
Edited to note that two XP51s were used throughout the war by NACA, 41-038 and 41-039. Both were Allison engined.
Dan/Slack
(http://www.onpoi.net/ah/pics/users/169_1089772458_mustangx.jpg)
(http://www.onpoi.net/ah/pics/users/169_1089772430_xp51b.jpg)
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This is my original post under the NACA Spitfire thread. In that thread the majority of the poster's agree that the spitfire roll rates in the NACA are invalid because the airframe was "tired".
What are the specs of the Mustang X? Was it a better performer than the P51B? I would have to know that in order to even speculate. The NACA test was probably the two XP51's they had on hand. Do you know if that test is the result of actual flight test's or is a slide rule comparison?
Crumpp
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That could explain the discrepancy in the NACA roll rates on the FW-190 with the Luftwaffe and RAF reports. Unfortunately it is the only record in existence of the "measured" roll rates. The RAF test praises the roll rate of the 190 saying:
"Incrediable alieron rolls which would tear the wings off a 109 or a Spitfire were possible."
"Appears to the following pilot to simply flick 180 degrees in a roll no Spitfire could possibly follow"
"Extremely fast, precise, and controllable rate of roll."
The Luftwaffe calls the roll rate:
"A significant advance in fighter aircraft performance which will have positive result in combat."
The 190A5/U4 the USAAF tested was in "good condition" for a crash-landed captured aircraft. In fact though, it needed extensive repair on the engine and airframe that is listed under the test set up. Including missing main wing spar bolts. It was a "tired" airframe. Does anyone have the Detailed Aircraft Set up for the NACA roll rate test's?
Also in reference to that 190A5's condition:
In glancing over the Luftwaffe FW-190A1 thru FW-190A9 Technical manual I noticed a large section devoted to aileron adjustment. In fact, jigs and templates for aileron adjustment are listed as part of the special tools FW-190's needed for maintenance. At the top of each page was what appeared to be a caution statement saying improper adjustment of the ailerons had an adverse effect on the maneuverability of the 190. This is confirmed by Hpt. Gollabs report to the RLM on 190 performance. It is also appears to be part of the maintenance crews pre flight and post flight checks to confirm the proper adjustment.
All the test flight reports I have seen ONLY the German and the USAAF test mention aileron problems in a turn with the 190. The German report warns against improper aileron adjustment AND denotes it's adverse effect on the 190's turn performance. The USAAF test simply notes aileron flutter, reversal, and tip stalling.
Here is the actual verbiage from the RLM report:
http://www.terra.es/personal2/matias.s/fw190.html
My Pilots Manuals and Technical Manuals for the FW-190 are in the possession of a German engineer and pilot friend of mine who is checking my translations and attempting to answer some other questions. When I get them back their will be more info on this posted at the above website.
Obviously no one is claiming the 190 should outturn Spitfires or any other plane, which historically it could not. This does though point to the obvious lack of detailed technical knowledge the allies had in the day to day maintenance of Luftwaffe Aircraft and calls into the question using strictly allied sources as the end all word in German Aircraft performance. And questions the NACA report results as the definitive answer to roll rate performance.
Let me know your thoughts on this.
Crumpp
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There are some other replys and answers under that thread. I don't want to Hijack this one. Please check it out and let me know your thoughts.
Crumpp
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Anybody know the type of oxygen system that was onboard that Spitfire that reached 40,000 plus feet AGL?
Crumpp
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Crump thanks :D
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http://webs.lanset.com/aeolusaero/Articles/Oxygen%20Systems%20history--Pt1.htm
One of the most overlooked aspects of High Altitude combat is the efficiency of the Oxygen system.
The Allies copied the Germans in the beginning but went from High pressure to low pressure tanks. The allies used compressed Oxygen and an overpressure delivery system by the end of the war. The overpressure system is "leaky" by nature and pretty much impossible to get 100 percent O2 delivery. The overpressure releases around the seal of the mask momentarily breaking it. When the pilot inhales the seal is reestablished. Some ambient air though leaks past until the pressure differential closes the seal.
The Germans did not use an overpressure system as standard O2 delivery on their single engine day fighters. They used a high pressure, on-demand type regulator with a sensor, which regulated a breathing mixture of air and pure O2 depending on altitude. High-pressure liquid oxygen tanks fed it. Since it is on demand and at absolute pressure the seal remains intact and a higher percentage of O2 reaches the pilots lungs.
The German mask systems did a better job of delivering more O2 to the pilot but at a lower pressure. The allied system of overpressure though makes maximum use of the O2 that does reach the lungs by increasing the Partial Pressure and thereby increasing O2 absorption.
Crumpp
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Originally posted by Crumpp
Anybody know the type of oxygen system that was onboard that Spitfire that reached 40,000 plus feet AGL?
Crumpp
Galitzine, who flew the interception of the Ju86R, said they were specially selected and trained for the high altitude flight in the modified Spit IX. Quoting Galitzine from Price's "Spitfire-A Documentary History"
"To conserve our strength and delay the effects of oxygen shortage at high altitude, we were enjoined to make all our movements slowly and deliberately. Enverything had to be done in an icy calm manner".
There is no mention of a special oxygen system, just the heated flight suit. The Spit had also been modified by having all armor plate removed as well as the machine guns etc. It did have a normal wingspan, not the pointed tips of the VII.
The Spit VII, being a dedictated high alt fighter had the pressurized cockpit.
Dan/Slack
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Originally posted by Crumpp
This is my original post under the NACA Spitfire thread. In that thread the majority of the poster's agree that the spitfire roll rates in the NACA are invalid because the airframe was "tired".
What are the specs of the Mustang X? Was it a better performer than the P51B? I would have to know that in order to even speculate. The NACA test was probably the two XP51's they had on hand. Do you know if that test is the result of actual flight test's or is a slide rule comparison?
Crumpp
The only info I caould find is from Gruenhagen's book "Mustang-The Story of the P51 Fighter"
It shows speed comparisions and includes the Mustang X. Not sure if it helps or not.
Dan/Slack
(http://www.onpoi.net/ah/pics/users/169_1089779597_mustangdata2.jpg)
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Guppy35,
The combat radius values in the AHT appear to be a bit contradictory; for the early P-47D it gives 425 miles with 305 gal. internally and 300 gal. externally (2x150gal.), for the late P-47D it gives 600 miles with 370 gal. internally and 300 gal. externally. Probably later radius is for very slow speed cruise power setting which was unpractical in the ETO but possible in the PTO.
Crumpp,
I don't know which NACA test you are talking about? AFAIK NACA never tested roll rates of the Fw 190. The curve for the Fw 190 in the NACA 868 (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif) comes from the RAE tests as well as curves for the Spitfires, Typhoon and Mustang (XP-51), P-51B data comes from NACA's own test. The RAE report claims that the tested Fw 190 had heavier ailerons than other two they had that time.
The Mustang had several different aileron combinations during war years. Early Mustang I (same as XP-51) had geared tabs and quite small trow in ailerons which resulted light ailerons througout speed rang, later models had internal balance with or without sealing and larger throw (throw could be changed in the field). In addition NACA and RAE tested several experimental combinations.
gripen
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Thanks Gripen.
Have you seen the RAE report? In just thumbing thru the NCAC 868 report it seems they used a combination of actual flight test and wind tunnel evaluations on actual wings.
They do not list WHICH A/C are based on flight test and WHICH are from wind tunnel extrapolation.
They do say that the wind tunnel test's do acount for a wide range of variables which will effect performance and can only give a general estimate.
Crumpp
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They do say that the wind tunnel test's do acount for a wide range of variables
Change that to "DO NOT ACCOUNT for a wide range of variables"
Crumpp
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Crumpp,
I have copy of the report (RAE TN No. 1231), it's available from the PRO (http://www.nationalarchives.gov.uk/) as DSIR 23/12865 or AVIA 6/10353.
I have seen most of the original reports they used to create that chart in the NACA 868 (Zero, P-63, F4F, P-40F, P-47 and F6F). Basicly all are real test light data sets (some curves might be extrapolated from 30lbs values and Zero data set does not contain exact control force measurements).
gripen
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Then that would explain the discrepancy in the Tactical Trials of the P51B and the FW-190 conducted in England and the NACA 868.
NACA 868 probably accurately reflects the curve of a 190's roll rate it does not accurately reflect the speed of the roll.
Do you know the name of that report so I can check it out?
Thanks
Crumpp
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Nevermind Gripen,
You already named the report. This is what happens when you post after running 5 miles!
LOL
Thanks
Crumpp
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Gripen I have used every combination of the report numbers you gave me to search the National Archives. It is not showing up. Can you give me some more Information on that report.
Thanks
Crumpp
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Crumpp,
Just follow the link (http://www.nationalarchives.gov.uk/) then choose "Search our cllections" and "> our catalogue (PROCAT)". After that catalogue page opens, now type DSIR 23/12865 to the "go to reference" in upper left corner and click enter. And there you are; "F W 190 aircraft: fighter aileron comparison".
gripen
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Got it.
The PROCAT was key.
Thanks for the help.
Crumpp