Author Topic: Spitfire IX/Merlin 61 at high altitude  (Read 1946 times)

Offline MiloMorai

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Spitfire IX/Merlin 61 at high altitude
« Reply #15 on: July 12, 2004, 07:38:26 PM »
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:

Offline Guppy35

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Spitfire IX/Merlin 61 at high altitude
« Reply #16 on: July 12, 2004, 08:27:51 PM »
Quote
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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Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #17 on: July 12, 2004, 08:28:46 PM »
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

Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #18 on: July 12, 2004, 08:32:15 PM »
Quote
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

Offline J_A_B

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Spitfire IX/Merlin 61 at high altitude
« Reply #19 on: July 12, 2004, 08:49:06 PM »
"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

Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #20 on: July 12, 2004, 09:15:40 PM »
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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

Offline J_A_B

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Spitfire IX/Merlin 61 at high altitude
« Reply #21 on: July 12, 2004, 09:36:56 PM »
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

Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #22 on: July 12, 2004, 09:48:08 PM »
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

Offline Hades55

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Spitfire IX/Merlin 61 at high altitude
« Reply #23 on: July 12, 2004, 10:06:42 PM »
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 :)

Offline Guppy35

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Spitfire IX/Merlin 61 at high altitude
« Reply #24 on: July 13, 2004, 12:09:25 AM »
Quote
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
Dan/CorkyJr
8th FS "Headhunters

Offline gripen

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Spitfire IX/Merlin 61 at high altitude
« Reply #25 on: July 13, 2004, 04:45:36 AM »
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

Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #26 on: July 13, 2004, 05:43:05 AM »
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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

Offline MiloMorai

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Spitfire IX/Merlin 61 at high altitude
« Reply #27 on: July 13, 2004, 06:13:54 AM »
Quote
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?

Offline Crumpp

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Spitfire IX/Merlin 61 at high altitude
« Reply #28 on: July 13, 2004, 06:59:08 AM »
The engine is the Gryphon 65. The one powering the Spitfire Mk IVX.

Quote
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

Offline MiloMorai

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Spitfire IX/Merlin 61 at high altitude
« Reply #29 on: July 13, 2004, 07:13:56 AM »
Quote
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



Notice the info board under the prop shaft