Spitfire IX/Merlin 61 at high altitude

[Crumpp]

BTW Milo,

Price does specifically say the test's were conducted before the P51B entered service in the European Theater.

Crumpp

[Crumpp]

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

[gripen]

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

[MiloMorai]

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).

[Guppy35]

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.

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

[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

[Guppy35]

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

[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

[Guppy35]

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

[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

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

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

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

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

[Crumpp]

Anybody know the type of oxygen system that was onboard that Spitfire that reached 40,000 plus feet AGL?

Crumpp

[Glasses]

Crump thanks

[Crumpp]

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

[Guppy35]

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

[Guppy35]

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