Merlin engine in Ace's

[BulletVI]

http://www.spitfireperformance.com/spit1vrs109e.html

Ok from the above link read what P/O David Crook has said in his first paragraph.its about a 1/4 of the way down the page

Now to me that sounds like he throttled up to 3000 rpm then initiated his push past to gain wep. ????

[RTHolmes]

not hunting around to find that, why dont you just quote it?

[Chalenge]

Bullet you should have realized by now that the RPM control is pitch control of the propeller. Lower RPM is broader pitch and higher RPM is thinner pitch or in other words when you decrease RPM to minimum you are in effect feathering the prop. When the engine can no longer produce a certain minimum of power it cannot maintain the propeller at higher RPMs. This is why at certain extreme altitudes the engine must be left at FT and only the engine RPM controls managed for maximum endurance or even left at highest RPM attainable for that altitude just to remain flying.

[BulletVI]

not hunting around to find that, why dont you just quote it?

i couldnt copy and paste it but here you are


A quote from P/O David Cook

     " It was obviously a matter of moments only before we where in the thick of it. I turned my trigger onto Fire, Increased the engine revs to, 3000 rpm by slipping the constant speed control fully forward. And pulled the plug, i.e. Pushed the small handle on the throttle quadrant that cuts out the automatic boost thus allowing one to use emergency power. "

Now to me that says he increased rpm's to 3000 then used wep to gain more power. Not what we have in game throttle up to 2750 rpms say and use wep and now have 3000 rpms ???? i dont know how you shall interpret this quote  but you are free to do so in any way

[Chalenge]

The constant speed control is a propeller control not an engine control.

[BulletVI]

The constant speed control is a propeller control not an engine control.

yes he had his throttle at max and his constant speed control at full as well to reach 3000rpm then wep to give more power thus more power more engine revs ok. so with wep on what would his revs be ? well that depends on hw much extra boost was supplied to the engine. If its plus 2 boost the the engine is now doing say 3250 rpm's ?????

[Chalenge]

No 3000 RPM. If you take any Merlin airplane up in AH (as far as I know) the RPM control is designed to deliver 3000 RPM whenever the engine is in WEP. Of course I dont know anything about Spitfires but I would bet that IRL if you moved to emergency boost without also setting the RPM correctly that it would not be as effective in combat. I dont believe that RPM would go above 3000 without wrecking the propeller.

[RTHolmes]

yes he dialled in 3000rpm and broke the wire on the boost. just like in AH, except we have one button which does both.

[jamdive]

i couldnt copy and paste it but here you are


A quote from P/O David Cook

     " It was obviously a matter of moments only before we where in the thick of it. I turned my trigger onto Fire, Increased the engine revs to, 3000 rpm by slipping the constant speed control fully forward. And pulled the plug, i.e. Pushed the small handle on the throttle quadrant that cuts out the automatic boost thus allowing one to use emergency power. "

Now to me that says he increased rpm's to 3000 then used wep to gain more power. Not what we have in game throttle up to 2750 rpms say and use wep and now have 3000 rpms ???? i dont know how you shall interpret this quote  but you are free to do so in any way

No bullet, why is this so hard to understand? It clearly states that he got the engine to run at 3000 rpm by increasing the prop rpm AND initiating boost. Stop twirling words in a manner to support your pointless argument.

[BulletVI]

Well there as we all know umpteen ways of looking at it and interpreting this story but to me it sounds like you can take the merlin engine up to 3000 rpms and use your wep for 5 minutes as any longer will cause engine damage. Oh and i was reading abit about prop rpms as well if the engine is at 3000rpm depending on the reduction gearbox setup the prop can be doing 9000rpms that i read in my collection of Air-plane the world encyclopaedia of aircraft from 1914 - 1999.

[gyrene81]

Amazing how the airframes engineer genius couldn't copy and paste the text...

P/O David Crook, with No. 609 Squadron at Middle Wallop, published an interesting account in his book of his most successful day of the Battle of Britain, 30 September 1940:

        It was now obviously a matter of moments only before we were in the thick of it. I turned my trigger on to 'Fire', increased the engine revs. to 3000 r.p.m. by slipping the constant speed control fully forward, and '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.
        A few seconds later, about six Me. 109s flew across right in front of us. I don't think they saw us till too late as we were coming out of the sun. Michael was leading Blue Section and I was leading Green, and immediately we swung our sections round and turned on to the tails of the enemy. They saw us - too late - and tried to escape by diving.
        We all went down after them in one glorious rush and I saw Michael, who was about a hundred yards ahead of me, open fire at the last Messerschmidt in the enemy line. A few seconds later, this machine more or less fell to pieces in mid-air - some very nice shooting on Michael's part. I distinctly remember him saying on the R.T., 'That's got you, you bastard,' though he never recollects it!
        The victim that I had selected for myself was about 500 yards ahead of me, and still diving hard at very high speed. God, what a dive that was! I came down on full throttle from 27,000 feet to 1,000 feet in a matter of seconds, and the speed rose with incredible swiftness - 400 m.p.h., 500, 550, 600 m.p.h. I never reached this speed before and probably never shall again. I have a dim recollection of the sea coming up towards me at an incredible rate and also feeling an awful pain in my ears, though I was not really conscious of this in the heat of the moment. I pulled out of the dive as gently as I could, but the strain was terrific and there was a sort of black mist in front of my eyes, though I did not quite 'black out'.
        The Messerschmidt was now just ahead of me. I came up behind him and gave him a terrific burst of fire at very close range. The effect of a Spitfire's eight guns has to be seen to be believed. Hundreds of bullets poured into him and he rocked violently, then turned over on his back, burst into flames and dived straight down into the sea a few miles off Swanage. The pilot made no attempt to get out and was obviously dead. I watched him hit the water in a great cloud of white foam, and then turned round to see what else was going on.
        A few of our Spitfires were chasing Messerschmidts all over the place and obviously a very nice little massacre was in progress, as a few seconds later I saw another Hun go into the sea. I then saw another Me. 109 going back to France as hard as he could and I chased him, caught him fairly easily, and put a good burst into him. He swerved slightly, his cockpit covering broke off the machine and flew just past my head and he then dived steeply.
        I waited to see him hit the water, but he was only shamming, as he flattened out again just above the sea, and continued full speed for home, though his machine was now smoking and obviously badly hit.
        For the first time in this war, I felt a certain pity for this German pilot and reluctant to finish him off. From the moment I saw him, he had no chance of escape as my Spitfire was so much faster than his Messerschmidt, and the last few moments must have been absolute hell for him. I could almost feel his desperation as he made this last attempt to get away.
        But if I let him go, he would come back to England another day and possibly shoot down some of our pilots. In the few seconds during which all this was happening, I did not consciously make these reflections; my blood was up anyway and I was very excited, but distinctly remember feeling rather reluctant.
        However, I caught him up again and made no mistake this time. I fired all my remaining ammunition at very close range, and he crashed into the sea, going at a terrific speed, and disappeared immediately. I circled round the spot, but there was no trace of anything. 71

It's a real shame Bullet doesn't read with better comprehension...that entire page is about the Spit I with a constant speed propeller compared to the Bf-109Es in 1940.

[BulletVI]

yup sorry google chrome is weird on copy and paste from copyrighted pages and sutch But hey if you are 2 Dumb to understand me then i am not the Dumb one you are. all i am saying if in game we get 3000rpm with the wep on then to me that sounds wrong from what i have read it sounds like we can get 3000 rpm before we use wep and wep is that lovely little extra boost we get for diving on our target or for the escape

[Chalenge]

Bullet... end of story here... the RPM gauge in AH is prop RPM. You can prove it to yourself easily. Takeoff in your favorite airplane (probably the Spit XVI) and climb to 10k or so. Leave the airplane in auto-climb (in case you want to get back to auto-climb its ALT-X) and once you get to the target altitude shut the engine off. After the nose settles you will be back at your climb speed but you will be nose down gliding. Now pull the RPM back with either your RPM axis ir with the minus key "-" from the keypad. You will notice that your nose will raise a little relative to the horizon. Now if RPM was related to the engine how does it effect trim attitude? Simple! Its prop RPM! It has nothing to do with the engines manifold pressure.

[RTHolmes]

um no - the cockpit gauge shows the engine speed in rpm, the AH "rpm control" controls the prop speed (via its pitch.)

[Chalenge]

um no - the cockpit gauge shows the engine speed in rpm, the AH "rpm control" controls the prop speed (via its pitch.)

Check again.