RAF 150 octane

[Angus]

Data is from Duncan Smith, who lead his squadron in formation at that altitude. I'll look it up just in case.
I think Quill mentions that as well.
Now if you adjust the Turbocharger for higher alt, have lower wingloading due to extended wings, and in the case of  the Spit VII, - a Pressurised cockpit, how far do you get.
I have heard one claim of 49K, but I will have to get into the guy's logbooks to see it. Might happen one day though.

[justin_g]

The original document quoted DOES NOT "clearly state" that 130 octane is the fuel grade being used with +21lbs boost.

On 23.2.44 it mentions "service trials" with 130 Octane fuel. No boost level mentioned.

On 31.3.44 it mentions plug fouling as a result of the switch to 130 Octane fuel. No boost level mentioned.

THREE MONTHS LATER

On JULY 18th we see: "The modification of the aircraft to take 21 lbs boost continues." No mention of fuel type being used.

[Squire]

Im not sure what your getting at. If its not 150 octane fuel then what is it?

http://www.spitfireperformance.com/merlin66_18_25b.jpg

[Kev367th]

Even better

http://www.spitfireperformance.com/no1_25lbs.jpg

http://www.spitfireperformance.com/spit14at21.jpg

http://www.spitfireperformance.com/125wing-replacement-aircraft.jpg
New type hood I assume means change to bubble type canopy.

[justin_g]

Originally posted by Squire
Ok, but if what your saying is accurate then this doc also needs explaining to me.

http://www.spitfireperformance.com/no610orb.jpg

So, what fuel are they reffering to with 610 Sqn?

It indicates 130 octane fuel, with 21 lbs boost. Read the whole doc.

I was pointing out that the document does not state that 130 octane fuel was being used with 21 lbs boost. Also 130 octane is not a typo, they really mean 130 octane(a.k.a. 100/130, in US terminology).

1. It states that in Feb/March the Sqn switched fuel to 130 octane(no boost level mentioned), and that they had spark plug trouble as a consequence.

2. Then, 3 months later, they were modifying their aircraft for operation at 21 lbs boost, with no mention of the fuel grade then in use(presumably, 150 octane).

[Squire]

It was a presumption based on faulty info I had from another source. My bad. In any case I beleive the question has been satisified, at least for me.

[Neil Stirling1]

This as of 16th March 1944,

http://hometown.aol.co.uk/JStirlingBomber/130.jpg

Neil

[Scherf]

Hi Neil:

Thanks as ever for posting on this subject. I'm interested to see 60 O.T.U. on the list - it was the Operational Training Unit for Fighter-Bomber Mosquitos. I'm also intrigued to see the Merlin 21/23 as the test bed engine for the mossies - until now I've only ever seen the Merlin 25 in connection with 150 Octane.

For what it's worth, Lewis Brandon mentions in his wartime memoirs that when 157 Sqn. went over to chasing V-1s, the aircraft were modified by having their nose cones strengthened, stub exhausts fitted and the engines converted to use 150 Octane. He then says that with the exception of the exhausts, those modifications were retained when they went back to conventional night fighting. I believe they were using Mk.XIXs at the time - generally equipped with the M25 IIRC.

I'm on the road yet again, so I can't check in the book for the direct quote - will try to do so when I get back, though that could be weeks yet.

Cheers,

Scherf

[Neil Stirling1]

Thanks Scherf.

The information I have, is that as of July 1944, 96, 85 and 157 sqn were using 150 grade and increased boost, later 68 and 125 sqn Mosquito XXX's were modified and lastly the 1945 Edition of the Mossi FB VI Pilots notes clears +25lbs boost with 150 grade.

I look forward to hearing from you.

Neil.

[Karnak]

The surprising thing is that they are talking about doing so to Merlin 21/23 Mossie VIs.  I'd have expected them to use the more powerful Merlin 25 Mossie VIs for the task.

[Scherf]

Thanks for that Neil - seems to confirm what Brandon says.

Was it just ADGB with 150 octane, or did some 2nd TAF squadrons have it as well? There were both nightfighter and fighter-bomber mossies on 2nd TAF, as you no doubt are aware.

Will get you the quote from Brandon when next I'm home - as I say though, that could be some weeks.

Cheers,

Scherf

[Crumpp]

The information I have, is that as of July 1944, 96, 85 and 157 sqn were using 150 grade and increased boost, later 68 and 125 sqn Mosquito XXX's were modified and lastly the 1945 Edition of the Mossi FB VI Pilots notes clears +25lbs boost with 150 grade.

According to Dr Brett Stolle of the USAF Museum, only aircraft that consistanly ran 150 grade fuel were those involved in "Operation Diver" and in some cases "Operation Crossbow".

The British defence against the V-1 was codenamed Operation Diver.

When the attacks began in mid-June of 1944 there were fewer than 30 Tempests in 150 Wing to defend against them. Few other aircraft had the low-altitude performance to be effective. Initial attempts to intercept V-1s were often unsuccessful but interdiction techniques were rapidly developed. These included the hair-raising but effective method of using the airflow over an interceptor's wing to raise one wing of the Doodlebug, by sliding the interceptor's wingtip under the V-1's wing and bringing it to within six inches (15 cm) of the lower surface. Done properly, the airflow would tip the V-1's wing up, overriding the buzz bomb's gyros and sending it into an out of control dive. At least three V-1s were destroyed this way.

The Tempest wing was built up to over 100 aircraft by September; Griffon-engined Spitfire XIVs and Mustangs were polished and tuned to make them almost fast enough, and during the short summer nights the Tempests shared defensive duty with Mosquitoes. Specially modified P-47 Thunderbolts (P-47Ms) with half their fuel tanks, half their 0.5 in (12.7 mm) machine guns, all external fittings and all their armour plate removed were also pressed into service against the V-1 menace. There was no need for radar — at night the V-1's engine could be seen from 16 km (10 miles) or more away.

http://en.wikipedia.org/wiki/V-1_flying_bomb

Although trials were entered to try and get the fuel into general service, it simply caused too many problems.  The allies had enormous industrial potential but even they could afford to replace the engines on the frequency general use would have required.

This is further evidenced by Neils document, at the top is specifies "German Bumble Bomber":

http://www.spitfireperformance.com/spit14at21.jpg





Hopefully I will have some T.O.'s to post  from him soon.

Britain's 2 TAF consisted of four RAF Groups: No. 2 Group, No. 83 Group, No. 84 Group, and No. 85 Group. Of these four, only the first three were really available for the air-land battle in Normandy; 85 Group was under the temporary operational control of No. 11 Group, attached to an RAF home defense command.

http://www.usaaf.net/ww2/dday/ddpg4.htm

Operation Crossbow:

http://www.usaaf.net/ww2/preemptivedefense/pdpg4.htm

All the best,

Crumpp

[Neil Stirling1]

No V1's in Cornwall or in May 1944.

http://hometown.aol.co.uk/JStirlingBomber/Lizard.jpg

Date of conversion of 2nd TAF, 15 December 1944.

http://hometown.aol.co.uk/JStirlingBomber/date.jpg

Fuel now being introduced.

http://hometown.aol.co.uk/JStirlingBomber/knob.jpg

Delivery of Spitfire Mk XIV's modified for +21lbs boost.

http://www.spitfireperformance.com/125wing-replacement-aircraft.jpg


Please give Dr Brett Stolle of the USAF Museum my E-mail address and I will talk to him.

Neil

[Angus]

Our only Icelandic fighter pilot was chasing divers in the late autumn 1944. He flew a P51C at the time.
He caught some, but needed a shallow dive to catch up with them.
He told me that already at the time, both Tempests and Spit XIV's were faster and able to catch the V-1's in a level run.
"Faster than my Mustang" he said.

[Neil Stirling1]

Mossi FB VI Pilots notes

http://hometown.aol.co.uk/JStirlingBomber/FB+VI.jpg

http://hometown.aol.co.uk/JStirlingBomber/FB+VI+a.jpg

Neil