Scramble to 20,000ft Reference Section..Spitfire I

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Killratio
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Scramble to 20,000ft Reference Section..Spitfire I

Post by Killratio »

Guys, some handy operating notes, whether for general "hard" flying or climb type challenges in the Spitfire I.

I've put them here to avoid having to search through the pages of Styggron's "Challenge" thread
and because strictly, that thread was for the IIb. At some stage I will drag out the same information for the II.
I think I have the Merlin XII somewhere but not sure. I have about 4 different issues of the Spitfire II notes....

These come from my copies of the Spitfire I Pilot's Notes and the Merlin II, II and IV Notes for Pilots.

I hope you find them useful/interesting.

Pilot's Notes, Climbing.

(Note although it is blurry and looks like it could be "2800" max climb RPM is "2600"... the original is clearer).

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Pilot's Notes, Maxima/Minima

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Rolls Royce Operational Notes for Pilots on Merlin II, III, IV.

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One that is buried away somewhere in the notes but not in the above is the Minimum RPM at 12lbs/sq in ... which is 2300rpm. Minimum RPM at 6 1/4 is 2080 which IS in the notes above (and actually they've given 10rpm margin over what is the REAL safe minimum, which is 2070!!).


Also note that the "Pilot's Notes" were a living, breathing document. Any given copy you find will have updates to this or that date. It is perfectly possible to find a set which gives a 135C maximum radiator temp. That is because later, in view of experience AND necessity, the figures were relaxed. In addition, I have 275 odd maintenance/modification releases which sometimes precede changes and were, at other times, released to confirm what was already being done at squadron level. (Armour plate and rear view mirror releases being perfect examples of the later.) You will also see inconsistencies between RR pilot's notes on engines and RAF Pilot's Notes on the aircraft, relating to the engine. (RR 60C Rad for opening up, RAF Spitfire 70C Rad) This can be due to many factors, placement of sensors in the aircraft , radiator effectiveness, generalisation between engines, etc , etc. You can often find contradictions within the SAME set of notes!!

In short, if you take the most conservative of all the stated figures, you can't go wrong....THEN learn where you can cheat! ;)
<Sent from my 1988 Sony Walkman with Dolby Noise Reduction and 24" earphone cord extension>


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gulredrel
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Re: Scramble to 20,000ft Reference Section..Spitfire I

Post by gulredrel »

Thanks Darryl.
Will the engine produce 12 psi boost after fiddling with the prop and having 2600 rpm, cause the supercharger isn't turning that fast as in full fine pitch prop settings?
"Give me a ping, Vasili. One ping only, please."

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Killratio
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Re: Scramble to 20,000ft Reference Section..Spitfire I

Post by Killratio »

gulredrel wrote:Thanks Darryl.
Will the engine produce 12 psi boost after fiddling with the prop and having 2600 rpm, cause the supercharger isn't turning that fast as in full fine pitch prop settings?
The Merlin will produce 12 lb/sq in at a minimum of 2300 rpm according to Rolls Royce. I haven't tested it specifically Jens. Ungoverned and at 3000rpm, it will produce something more than 18!
Although the supercharger is engine geared, the maximum boost is not wholly dependent on the RPM simply because excess pressure is vented via the boost control. So it might look like this:
(illustrative, not actual!!)

3000rpm 18 generated - 6 vented = 12 power
2600rpm 16 generated - 4 vented = 12 power
2300rpm 12 generated - 0 vented = 12 power
2100rpm 10 generated - 0 vented = 10 power BUT stress on engine as all inputs are TRYING to produce 12 but airscrew is holding it back.

Hope that helps?

cheers

Darryl
<Sent from my 1988 Sony Walkman with Dolby Noise Reduction and 24" earphone cord extension>


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gulredrel
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Re: Scramble to 20,000ft Reference Section..Spitfire I

Post by gulredrel »

Thanks for the explanation. Will have an eye on it before ruining my engine :twisted:
Glad to have a simulated Merlin.
"Give me a ping, Vasili. One ping only, please."

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Killratio
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Re: Scramble to 20,000ft Reference Section..Spitfire I

Post by Killratio »

My pleasure!
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Styggron
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Re: Scramble to 20,000ft Reference Section..Spitfire I

Post by Styggron »

Thank you for posting these
Accufeel V2, C172 , B377+L049+COTS, B17G, Piper Cub,Commanche,Cherrokee,Spitfire,Bonanza, P47,P40,both Mustangs
Aircraft Factory Avro Anson, Albatros DIII,Heinkel He-219, F4U Corsair, P51H Mustang, Avro 504, BF109
Watch my incompetent flying Twitch

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