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View Full Version : Need info on the Spitfir IX 25lbs



GregGal
02-27-2008, 01:31 AM
What was its historical background? when did they increase the boost to 25 lbs, and why? was it commonly introduced on every Spit IX?

I know the spit is a bird very likely to overheat. I fancy 25lbs boost doesn't help that very much. (I usually fly without that info line on the right hand side wich sais (throttle 100%, Engine overheating, etc...)

Thanks!

Kurfurst__
02-27-2008, 05:38 AM
It entered operational trials in March 1944 with two Squadrons; subsequent technical difficulties with the engine and limited supplies of 150 grade fuel that was required for this boost (the USAAF escorts) was using up most of it meant that it remained limited to that extent.

Despite continuing technical problems (ignition) in november 1944 it was proposed that 20 Mk IX Squadrons in the 2nd TAF on the continent would convert to this boost; 150 grade supplies to the 2nd TAF begun in early 1945; an unknown number of units converted to the new boost, that was however almost immidiatelly recall after a number of fatal accidents attributed to the fuel; aircraft converted back to normal 18 lbs boost, as in 1943.

GregGal
02-27-2008, 06:03 AM
I see! Thank you! So it was only some kind of an experimental version.

luftluuver
02-27-2008, 06:06 AM
Originally posted by Kurfurst__:
It entered operational trials in March 1944 with two Squadrons; subsequent technical difficulties with the engine and limited supplies of 150 grade fuel that was required for this boost (the USAAF escorts) was using up most of it meant that it remained limited to that extent.

Despite continuing technical problems (ignition) in november 1944 it was proposed that 20 Mk IX Squadrons in the 2nd TAF on the continent would convert to this boost; 150 grade supplies to the 2nd TAF begun in early 1945; an unknown number of units converted to the new boost, that was however almost immidiatelly recall after a number of fatal accidents attributed to the fuel; aircraft converted back to normal 18 lbs boost, as in 1943.
Nice to see admittance that the USAAF used 150 fuel.

Now Kurfurst has troubles getting and keeping his facts straight. There was no shortage of 150 fuel. The spark plugs could foul up but were easily cleaned with a burst of throttle (this would be on P-51s doing escort duty ie at cruise speeds). The accidents were caused by improper training of the pilots when flying a/c using 150 fuel.

Oh yes, 25lb boost was being tested as early as Oct 1943. Full service approval for the use of 25lb boost was given March 10 1944.

JG53Frankyboy
02-27-2008, 06:22 AM
http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html

Xiolablu3
02-27-2008, 07:02 AM
From that link :-

The Royal Aircraft Establishment (RAE) reported in Technical Note No.Aero.1501(Flight) that a Mustang III (Merlin V-1650-7), flying at +25 lb./sq.in. as received from Squadron, obtained 382 mph at sea level. 404 mph was obtained at sea level after "cleaning up" the aircraft by removing the bomb racks and aerial bracket, repainting the wing's leading edge and rubbing down the aircraft'


Mustang III 25lbs boost - 382mph with bomb racks and 404mph at sea level when clean, WOW!



http://www.wwiiaircraftperformance.org/2taf150_112044.gif


It was decided that the Second Tactical Air force would change over from 100/130 grade fuel to 100/150 grade fuel from the 15th December 1944. :-


http://www.wwiiaircraftperformance.org/150grade/date-of-change.jpg



http://www.wwiiaircraftperformance.org/150grade/are-using-4a.jpg

Xiolablu3
02-27-2008, 07:35 AM
Sorry to go OT but I just had to post this...


http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif I just googled 150 grade fuel and found this piece by Kurfurst, (possibly very old?) 'A response' to Mike Williams piece about the 109K4 vs Spit XIV, funny reading!

http://kurfurst.atw.hu/articles/MW_KvsXIV.htm

Kurfy, you have to wonder, reading that piece, just how the Germans managed to lose when they had such superior aircraft AND had on hand 1000 Me109's flying in early 1945! Add to that a few hundred Me262, a lot of Fw190's, some He162's.

Just what were all these planes doing at that time? Surely thats an INCREDIBLE force of power right there. At least 2000 planes which are JUST the fighters!?!? ADd all the other units of 410's, Ju88's, 188's, AR234's, Heinkels, Stukas etc etc...

Why were the Luftwaffe so rarely seen in late '44- early '45 when they had this incredible strength on hand? German AA gunners were shooting at everything in the skies at this time, (BoddenPlatte) as they could be so sure that they were Allied planes and not German. German tanks covered in twigs and trees to protect themselves from the air..

Mottos of 'Where is the Luftwaffe?'...they had all these planes yet they were not flying?


Something is very amiss there....

And to top it off theres a porn advert at the top, http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

JG53Frankyboy
02-27-2008, 08:09 AM
even 1 million planes are worthless if you are lacking trained pilots to man them and fuel to fill their tanks...................

Manu-6S
02-27-2008, 08:22 AM
SpitIX 25lbs?

http://bp2.blogger.com/_n06_7jikkGQ/ReM32Fm5NJI/AAAAAAAAAF8/6kGEI6A71NM/s400/homer_angry2.gif

Jaws2002
02-27-2008, 09:36 AM
Originally posted by Xiolablu3:
Sorry to go OT but I just had to post this...


http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif I just googled 150 grade fuel and found this piece by Kurfurst, (possibly very old?) 'A response' to Mike Williams piece about the 109K4 vs Spit XIV, funny reading!

http://kurfurst.atw.hu/articles/MW_KvsXIV.htm

Kurfy, you have to wonder, reading that piece, just how the Germans managed to lose when they had such superior aircraft AND had on hand 1000 Me109's flying in early 1945! Add to that a few hundred Me262, a lot of Fw190's, some He162's.

Just what were all these planes doing at that time? Surely thats an INCREDIBLE force of power right there. At least 2000 planes which are JUST the fighters!?!? ADd all the other units of 410's, Ju88's, 188's, AR234's, Heinkels, Stukas etc etc...

Why were the Luftwaffe so rarely seen in late '44- early '45 when they had this incredible strength on hand? German AA gunners were shooting at everything in the skies at this time, (BoddenPlatte) as they could be so sure that they were Allied planes and not German. German tanks covered in twigs and trees to protect themselves from the air..

Mottos of 'Where is the Luftwaffe?'...they had all these planes yet they were not flying?


Something is very amiss there....

And to top it off theres a porn advert at the top, http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif


There was no shortage of planes in LW at that point in the war. They just didn't have pilots, or fuel or both.

A lot of brand new aircraft were bombed and destroyed at aircraft factories, waiting delivery, on route, or just sitting on the ground.

lrrp22
02-27-2008, 12:06 PM
Originally posted by Kurfurst__:

Despite continuing technical problems (ignition) in november 1944 it was proposed that 20 Mk IX Squadrons in the 2nd TAF on the continent would convert to this boost;

Ignition/backfire problems were completely eliminated by mid-summer of '44. ADGB was very satisfied with the use of 150 grade/+25 lbs boost by September.


150 grade supplies to the 2nd TAF begun in early 1945; an unknown number of units converted to the new boost, that was however almost immidiatelly recall after a number of fatal accidents attributed to the fuel; aircraft converted back to normal 18 lbs boost, as in 1943.

Source? What you fail to mention is that it was only 4-5 sqn's of Mk XVIs that reverted. There is absolutely no evidence that any of the far more numerous Spit IXLF or Spit XIV sqns reverted.

BTW, the use of 150 grade/+25 lbs boost by ADGB Mustangs in 1945 has now been definitively confirmed for both of the main Mustang bases.

Brent