Suggested, complete Spitfire lineup for Aces High

[MiloMorai]

Originally posted by Karnak
Spitfire LF.Mk Vb, Merlin 45M at +12lbs boost for 1941 to mid 1942.

According to S:tH, the 45M was Mod 969 and was introduced 20-4-43.

[mw]

Nice list Karnak!  

[Squire]

Yes, the L.F. Vbs with the Merlin 50Ms (low alt rated) were +18 lbs boost (emergency setting) and were introduced spring 1943. Many with clipped wings, some with standard.

...you will hear the screaming in the MA for many miles if they ever introduce it too, hehe.

[Nashwan]

During the battle, 10 July-10 Oct, 22 000 tons was issued.... 22/6=ca.3.5 weeks, let`s be generous and say, enough for either

a, only a month b] if everyone uses it.[/b]
b, 3-4 months if only 25-33% of the fighters are using it.

No, 22,000 tons is enough for 100% of the  fighters, if the bombers aren't using it.

And as the 22,000 tons figure is given by Wood and Dempster as fuel used by FIGHTER Command, I think it's safe to say the bombers weren't using any of it.

22,000 tons = 6,844,444 gallons.

The Spitfire or Hurricane carried a maximum of about 85 gallons, so assuming each sortie used the maximum amount of fuel (ie assuming the planes landed with empty tanks), 6,844,444 gallons is enough for something over 80,000 sorties.

That's over a period of 13 weeks, which works out at about 6200 sorties per week.

Actuall fighter command sorties, according to Hooton, Eagle in Flames:


(the Luftwaffe figures do not reflect fighter bomber sorties)

As you can see, 22,000 tons of fuel is enough for over 6,000 sorties per week, and the RAF didn't actually fly that many operational sorties, although non operational ones would account for the difference.

The RAF had ample fuel, and issued Fighter Command with more than enough 100 octane fuel for every fighter sortie flown in the BoB.

[MiloMorai]

Thanks Nashwan for confirming my rough calculation.

[Angus]

So, they indeed DID fly totally on 100 octs.
That means that our Spitfire is not a BoB comparable model, - it rather would belong to France in May 1940, or over the Home front in 1939.
The airscrews were later to it, but bear in mind that the top speed of the coarse 2 bladed ones was actually a tad higher than on the 3 blade early rotol ones.
A Spitfire with a 3 blade rotol already outclimbs the 109E4 (the data I have) on 87 octs.
Top speed would be in the 109's favour.
But with 100 octs....
And for high alt, the Mk II entered in the BoB....

Anyway, Karnak is the man, that is the list

[Karnak]

Spitfire Mk Vs aren't really my thing and I was merely listing the engine that kev367th listed.  

Which engine was the Spitfire Mk V using in 1941 and '42 at +12lbs boost?  That is the one that we should have.

[Squire]

Merlin 45 on most of them, for the Spitfire Vb. +12 lbs.

...also I think the LF VIIIs were rated at +16 lbs (like the Merlin 66 LF IXs) not +18lbs.

[Karnak]

Merlin 45 at +12lbs boost for the Spitfire Mk Vb then.


I understood the Merlin 66 to be rated at +18lbs boost on 100 octane and +25lbs boost on 150 octane.

I'll have to go over my data again when I get home, if I have time tonight.

[mw]

Here's the short version of Battle of Britain Spitfires and 100 octane fuel.   +12 lb boost was obtained on Spitfire Is, Hurricanes and Defiants  by operation of the boost control cut-out and could only be employed in conjunction with 100 octane fuel.  Emergency use of +12 lbs./sq.in boost was officially adopted 20 March 1940 with the release of the Air Ministry's Air Publication A.P.1590B/J.2-W..   Below is documentation of use of emergency boost, only obtained with 100 octane fuel, by Spitfire Squadrons during the Battle of Britain: 19, 41, 54, 64, 65, 66, 72, 74, 92, 152, 222, 234, 602, 603, 609, 610,  611, 616 = 18 squadrons.  I havn’t got around to checking on 266 yet.  Spitfire Squadrons  began converting to 100 octane and +12 boost in March 1940:



Spitfire Squadrons used it over Dunkirk in May 1940:

19 Sqdn., F/LT Brian Lane, 26 May 1940: “I gradually drew away from E/A using 12 lb. boost”


and right on through the Battle...

41 Sqdn:, F/Lt. John Webster, 28 and 29 July 1940: "I returned home at 0 feet 12 boost"
http://www.spitfireperformance.com/webster-28-7-40.jpg

41 Sqdn., P/O George Bennions, 28 July 1940: “Using the emergency boost”
http://www.spitfireperformance.com/bennions-28-7-40.jpg

54 Sqdn., Al Deere, 26 May 40: “I gave chase using +12 boost”
http://www.spitfireperformance.com/deere-26-5-40.jpg

54 Sqdn., F/Lt George Gribble, 15 August 1940: “I dived to the attack, using 12 boost”
http://www.spitfireperformance.com/gribble-12lbs.jpg

54 Sqdn., P/O Colin Gray (NZ), 25 May 1940: “I pressed the emergency boost tit”

64 Sqdn., P/O Art Donahue, 5 August 1940, “I pushed in my emergency throttle”

65 Sqdn., Jefferey Quill: “It was only shortly before the Battle of Britain that we changed over to 100 octane.”

66 Sqdn., F/O Robert Oxspring, 6 September 1940: “I shoved the throttle through the gate for emergency power.”

72 Sqdn., P/O R. D. Elliott, 9 September 1940: “with the aid of MAX Boost (12 lbs)”
http://www.spitfireperformance.com/elliott-9-9-40.jpg

74 Sqdn., P/O John Freeborn, 24 May 1940: “I got away from it by using the boost cut out”.
http://www.spitfireperformance.com/freeborn-24-5-40.jpg

74 Sqdn., F/Lt D. P. Kelly, 28 July 1940: “I found it necessary to use boost cutout”

92 Sqdn., Geoffrey Wellum, “Press the emergency boost override”

152 Sqdn., P/O Roger Hall, 4 September 1940: “emergency boost must not be used for more than five consecutive minutes, but now the occasion seemed to warrant the risk”

222 Sqdn., F/O D. McMullen, 15 October 1940: “I overtook E/A easily without 12 boost”

234 Sqdn., P/O Bob Doe: “Once we were in the vicinity of the enemy, I would 'pull the plug', which was the release so that we could get extra boost”

602 Sqdn., F/Lt Robert F. Boyd, 18 August 1940: “My Spitfire easily outdistanced Me 109's at 10 lbs boost 2800 r.p.m”
http://www.spitfireperformance.com/boyd-18-8-40.jpg

603 Sqdn., P/O James Morton, 28 August 1940: “I was being followed so pressed the tit”

603 Sqdn., P/O Ronald Berry, 31 August 1940: “To overhaul him I had to press the emergency boost”
http://www.spitfireperformance.com/berry-31-8-40.jpg

603 Sqdn., Sgt Jack Stokoe, 1 September 1940: “pushed in boost override”
http://www.spitfireperformance.com/stokoe-1-9-40.jpg

603 Sqdn., F/O Brian Macnamara, 27 September 1940: “with full throttle and the red lever pressed”

609 Sqdn., P/O David Crook , 30 Sept 1940: “'pulled the plug', i.e. pushed the small handle on the throttle quadrant that cuts out the automatic boost control thus allowing one to use emergency power”.

610 Sdqn: Hawkinge, July 1940: Check the fuel bowser


611 Sdqn., 21 March 1940: “The new aircraft are one by one being converted for the use of 100 octane fuel”
http://www.spitfireperformance.com/no611-100oct.jpg

616 Sqdn., F/O Hugh Dundas, 15 August 1940, “rammed the throttle 'through the gate' , to get the maximum power output, permissible for only a very limited time.”

For the expanded version see: http://www.spitfireperformance.com/spit1vrs109e.html

[Guppy35]

A bit tough to argue with that mw

Nice work and thanks for posting the combat reports etc.

Dan/CorkyJr

[Neil Stirling1]

http://hometown.aol.co.uk/JStirlingBomber/100+a.jpg

http://hometown.aol.co.uk/JStirlingBomber/100+b.jpg

http://hometown.aol.co.uk/JStirlingBomber/150+a1.jpg

In addition Merlin 24 and 25 +25lbs with 150 grade and later in 1945 the Centaurus V +12lbs with 150 grade.

http://hometown.aol.co.uk/JStirlingBomber/150+c3.jpg

http://hometown.aol.co.uk/JStirlingBomber/150+b2.jpg

Neil

[Squire]

Right you are Karnak, I was thinking of the latter Mk Vs (+16).

+18 lbs with the Merlin 66, and Merlin 70 series on 100 oct.

[Crumpp]

The only problem I have with Mikes comparision is the fact he compares different boost settings.

His page list's a Bf-109E1 prototype at "climb and combat" power against a Spitfire at +12 boost or it's emergency power.

Use of +12 boost was a definate overload condition for the engine as noted in paragraph 11 of the AP 1590B/J.2-W.

http://www.spitfireperformance.com/ap1590b.jpg

The Bf-109E DB 601A was capable of 1.42ata, a rating which clearly is the equivelent of (+12) boost for the Merlin.

From the Bf-109E4 Flugzeug-handbuch:



An early  DB601A power curve:



All the best,

Crumpp

[Angus]

Wholly cow!
I'll save that thread.
If I get lucky, I'll have an interesting input in some 2 days.
All the best lads !