PDA

View Full Version : was the merlin 266 ever cleared for 25lbs boost?



thefruitbat
11-27-2009, 04:27 PM
Hi, i've been flying the new beta spit MkXVI's that have just been released somewhere. Now, these were temporarily accidently moddeled with 25lbs boost, which has been changed to 18lbs boost for the final.

Now, to my queston, was the 266 actually ever cleared for 25lbs boost? I've found a document over at spitfire performance that clears 150 fuel for 2nd TAF for

'up to 5 squadrons of spitfire XVI with merlin 266 engines <span class="ev_code_RED">if these are cleared at 25 lls. boost</span>.'

on the 20/11/44, so any ideas, i've searched through here to, and seen 21lbs mentioned as well???

cheers fruitbat

thefruitbat
11-27-2009, 04:27 PM
Hi, i've been flying the new beta spit MkXVI's that have just been released somewhere. Now, these were temporarily accidently moddeled with 25lbs boost, which has been changed to 18lbs boost for the final.

Now, to my queston, was the 266 actually ever cleared for 25lbs boost? I've found a document over at spitfire performance that clears 150 fuel for 2nd TAF for

'up to 5 squadrons of spitfire XVI with merlin 266 engines <span class="ev_code_RED">if these are cleared at 25 lls. boost</span>.'

on the 20/11/44, so any ideas, i've searched through here to, and seen 21lbs mentioned as well???

cheers fruitbat

Daiichidoku
11-27-2009, 08:51 PM
http://img.photobucket.com/albums/v479/Daiichidoku/0568.gif

Buzzsaw-
11-27-2009, 09:08 PM
Salute

Yes, the Spitfire XVI's equipped with the Packard manufactured Merlin 266's were cleared for +25 boost from January of '45 till early April of '45.

However, it was found that unlike the Rolls Royce Merlin 66's which equipped the Spitfire IX's, the Merlin 266's in the Spit XVI's had reliability problems when using that boost level, and a decision was taken in late March and early April to reduce boost level back to +18.

The problem was in the process of being solved, through the intervention of North American based Packard engineers, but they were not able to provide the solutions before the war ended. The same reliablity issues appeared in July of '44 for the Rolls Royce Merlins running at +25 boost, but the Rolls Royce engineers based in England were on the spot and were able to deal with those problems much faster.

Although the basic design was the same, there were differences between the Rolls Royce Merlin 66 and the Packard Merlin 266, parts were not interchangeable.

Kurfurst__
11-28-2009, 03:51 AM
Twenty pager be sure! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Kettenhunde
11-28-2009, 07:44 AM
http://forums.ubi.com/images/smilies/partyhat.gif

Kettenhunde
11-28-2009, 08:05 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> a decision was taken in late March and early April to reduce boost level back to +18. </div></BLOCKQUOTE>

Interesting that date corresponds to the withdrawal of the fuel from service.

As I understand the history of 100/150 grade use in the Merlin 66 Spitfires, we have two squadrons used in during service trials as part of the ADGB approved in May 1944. The fuel was withdraw from use when the anti-diver campaign was concluded.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Early in March, 1944 Service Trials with Spitfire IX L.F aircraft operating at + 25 lbs./sq.in boost and using 150 grade fuel were commenced at Milfield. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> In view of the success of the trials at Milfield, Wittering and Southend, the trials were extended on the 3rd may 1944, to include all aircraft in No.1 and 165 squadrons, at Predannack. </div></BLOCKQUOTE>


The fuel was still undergoing trials until August 1944.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> All pilots reported most favorably on the value of the high boost pressures obtainable with 150 Grade Fuel, however, Technical Staff felt that before the fuel was introduced on a large scale that the causes of backfires must be established and that at least 12 engines should complete 200 hours each. 3 </div></BLOCKQUOTE>

http://www.wwiiaircraftperform.../16-june-44-doc.html (http://www.wwiiaircraftperformance.org/150grade/16-june-44-doc.html)

in September 1944 it was withdrawn from ADGB use.

http://www.wwiiaircraftperform.../150-grade-fuel.html (http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html)

So it was in service trials for quite some time due to maintenance difficulties without general operational approval.

It next was in operational use in the 2nd TAF in February 1945 but was again withdrawn from service in April 1945 after a series of fatal accidents.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Senior Intelligence Officer of 126 (RCAF) Spitfire Wing, 2 TAF, noted in his daily operational summary on 20 April 1945 after the crashes of two Spitfires; "The incidents followed a number of engine problems that were attributed to the introduction of 150-grade fuel in early February. Pilots mistrusted it, and were no doubt relieved when the AF brass decided to revert to 130-grade. The vast majority of pilots, I'm sure, were beginning to wonder if the additional seven pounds of boost they got from 150-grade fuel were worth the price being paid."[11]
</div></BLOCKQUOTE>

-Berger, Monty and Street, Brian Jeffrey.Invasion Without Tears. Toronto, Canada: Random House, 1994 (1st ed) ISBN 0-394-22277-6

In summary, the fuel had a few airplanes undergoing service trials with operational use limited to 3 months in the 2nd TAF only.

All the best,

Crumpp

http://forums.ubi.com/eve/foru...141078357#9141078357 (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/1701049157?r=9141078357#9141078357)

thefruitbat
11-28-2009, 08:30 AM
Thanks for the info so far, pretty much answers what i needed to know.

So it would be reasonable to assume that there were 5 squadrons operating MkXVI at 25lbs between feb and april 1945... Correct?

Also, Kurfurst, i know this is going back a bit, but in the thread that crazy ivan started before the spitIX 25lbs got released, asking for info, you mention 21lbs boost, do you have any info on that?

thanks in advance,

fruitbat

Kettenhunde
11-28-2009, 08:58 AM
Fruitbat,

I will say use extreme caution with any internet article posted from a gaming site.

Original sources are great but do not read into them or project meaning that just does not exist.

For example we see the conclusion being drawn that fighter aircraft from the ADGB continued to use 100/150 grade after the trials. Of course this would be disobeying a direct order and contrary to the strict regulation of aircraft maintenance.

The "evidence" is a couple of combat reports...

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Its unclear as to the degree to which this decision was carried out as of November 1944 Fighter Command was apparently still using 2,000 tons of 150 grade fuel per month. 35
Combat Reports show that the the UK based Mustangs of ADBG were in fact still running high boost, only made possible through the use of 150 grade fuel, on operations over the continent and Germany in 1945. 36, 37 </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> 65 Squadron (S/L Westersra) Mustang III (Funtington, B.7 25Jun, B.12 15Jul) YT </div></BLOCKQUOTE>

http://www.wwiiaircraftperform...pearson-5april45.jpg (http://www.wwiiaircraftperformance.org/mustang/combat-reports/65-pearson-5april45.jpg)

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> 129 Squadron, Mustang III (Coolham ) DV </div></BLOCKQUOTE>

http://www.wwiiaircraftperform...-davis-23march45.jpg (http://www.wwiiaircraftperformance.org/mustang/combat-reports/129-davis-23march45.jpg)

http://www3.sympatico.ca/angels_eight/2tac.html

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> On D-Day, Flying Officer Ashworth proceeded to No. 83 Group Support Unit at Redhill in Surrey where he flew Mustangs. He was then posted to No. 65 "East India" Squadron.

June 10, he moved with the Squadron to a newly captured aerodrome in Normandy. The Squadron formed part of the 2nd Tactical Air Force and was engaged on strikes against enemy railway yards, communications and troop concentrations. Corran Ashworth had a busy month of bombing in France, and on the 14th of June he was on reconnaissance (12 Planes) in the area of Rouen. He shot down a Me BF 109 G6 of the 2/ JG5: the pilot was not wounded but his plane was totally destroyed. He followed up with an Fw-190 near Argeantan on 17 June. </div></BLOCKQUOTE>

http://www.corranashworth.info/

Both are members of the 2nd TAF and once again, the time line fits with the 2-3 month operational use of 100/150 grade by the RAF before its withdrawal from service and not the conclusion the article leads the reader to follow of continuous use outside of either the limited service trials or the operational use by the 2nd TAF.

Use your best judgment!

Kettenhunde
11-29-2009, 11:39 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">So it would be reasonable to assume that there were 5 squadrons operating MkXVI at 25lbs between feb and april 1945... Correct? </div></BLOCKQUOTE>

I don't know what 5 squadrons you refer too.

126 wing RACF as quoted below was operating Spitfire Mk IX Merlin 66's. It was not until after the cessation of hostilities that the wing converted to Spitfire Mk XVI's post war.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Senior Intelligence Officer of 126 (RCAF) Spitfire Wing, 2 TAF, noted in his daily operational summary on 20 April 1945 after the crashes of two Spitfires; "The incidents followed a number of engine problems that were attributed to the introduction of 150-grade fuel in early February. Pilots mistrusted it, and were no doubt relieved when the AF brass decided to revert to 130-grade. The vast majority of pilots, I'm sure, were beginning to wonder if the additional seven pounds of boost they got from 150-grade fuel were worth the price being paid."[11] </div></BLOCKQUOTE>

-Berger, Monty and Street, Brian Jeffrey.Invasion Without Tears. Toronto, Canada: Random House, 1994 (1st ed) ISBN 0-394-22277-6

All the best,

Crumpp

thefruitbat
11-29-2009, 12:09 PM
I get that running at 25lbs boost had problems, and caused some accidents, and that it was withdrawn in april'45, but as you already say yourself, the 2nd TAF was using it between feb '45 and april '45.

403 squdron changed its mk IX's for mk XVI's in Belgium, in dec'44, and by VE day, 19 units had switched.

There were plenty of mk XVI's running around in the 2nd TAF between feb '45 till the end of the war, mainly in the fighter bomber role, as the XIV was considered the new main air supiriority fighter.

Kettenhunde
11-29-2009, 02:20 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I get that running at 25lbs boost had problems, and caused some accidents, and that it was withdrawn in april'45, but as you already say yourself, the 2nd TAF was using it between feb '45 and april '45. </div></BLOCKQUOTE>

It looks like about ~10 weeks worth of operational use before being withdrawn.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> 403 squdron changed its mk IX's for mk XVI's in Belgium, in dec'44, and by VE day, 19 units had switched. </div></BLOCKQUOTE>

OK!

thefruitbat
11-29-2009, 02:41 PM
Source here, Late Mark Spitfire Aces 1942-45 by Alfred Price,

http://books.google.co.uk/book...v=onepage&q=&f=false (http://books.google.co.uk/books?id=880o3Wwzn0MC&pg=PA27&lpg=PA27&dq=Spitfire+Mk+XVI+2nd+TAF&source=bl&ots=UnDArPd9hX&sig=wcxYAWilh1ytsCu0oNex-6jdUA0&hl=en&ei=0sESS4bwC8Ss4Qa8i_GBBA&sa=X&oi=book_result&ct=result&resnum=9&ved=0CCIQ6AEwCA#v=onepage&q=&f=false)

fruitbat

stalkervision
11-29-2009, 02:55 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kurfurst__:
Twenty pager be sure! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I just wish I had the innate talent to come up with topics like this. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

thefruitbat
11-29-2009, 03:21 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by stalkervision:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kurfurst__:
Twenty pager be sure! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I just wish I had the innate talent to come up with topics like this. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif </div></BLOCKQUOTE>

Hey!, it was an honest question http://forums.ubi.com/images/smilies/halo.gif

I'd hoped for a simple yes or no, lol!

Kurfurst__
11-30-2009, 02:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Also, Kurfurst, i know this is going back a bit, but in the thread that crazy ivan started before the spitIX 25lbs got released, asking for info, you mention 21lbs boost, do you have any info on that?

fruitbat </div></BLOCKQUOTE>

I don't recall the thread, but everything I've seen so far that the end of November 1944, the 2nd TAF IXs were cleared for +25, the Griffon XIVs and Packard XVIs for +21; the limits appear stayed as such until the problems with 150 grade resulted in the fuel withdrawn (and as a result to the normal boost of +18 allowable on 100/130 grade).

Operational use of the new boost limits began in the end of January/early February 1945, when 150 grade was first issued/consumed for combat use in the 2nd TAF.

thefruitbat
12-01-2009, 12:13 PM
I've only ever seen documents mentioning 25lbs for the XVI, can you remember where you saw 21lbs referenced, would like to know more.

cheers fruitbat