Spitfire & Hurricane flight model & engine performance thread. (1.09 patch)

[JtD]

It does matter, because it was necessary to modify the automatic boost control in order to have it deliver 12lb when in override. It would always have been possible to override it, but in the worst case you could end up with boost exceeded 30lb and destroy the engine instantly.

[Kurfürst]

Indeed JtD.

[bongodriver]

And there you have it....12lbs boost up to 1000' for take off or for a maximum of 3 minutes otherwise.

I'm sure nobody is suggesting 3 minutes was used to get to 1000'

[JtD]

A different system, bongodriver. It was limited to low altitude and could not provide boost at higher altitudes. Simply put, it had a full throttle altitude of 1000 feet, which would give you less than 9lb at altitudes exceeding 4000 feet. It's really just a take off setting.

[Osprey]

Originally Posted by JtD

It does matter, because it was necessary to modify the automatic boost control in order to have it deliver 12lb when in override. It would always have been possible to override it, but in the worst case you could end up with boost exceeded 30lb and destroy the engine instantly.

Not with the Spitfire II which is what Kurfurst is talking about. This has a Merlin XII engine designed for 100 only.

I am not sure why Kurfurst agreed with you in the subsequent post unless he forgot which aircraft he was talking about

Originally Posted by JtD

A different system, bongodriver. It was limited to low altitude and could not provide boost at higher altitudes. Simply put, it had a full throttle altitude of 1000 feet, which would give you less than 9lb at altitudes exceeding 4000 feet. It's really just a take off setting.

I agree, I don't have a problem with that, but it's the clearance to use it I'm talking about.

When I was 18 I didn't have clearance to take my engine in my Ford Fiesta 1300S into the red all of the time but when my six was occupied by another kid in an Escort or Golf I pulled the tit and away we went down those country roads like dickheads. After a while I blew the camshaft out of the side of the block, I'm pretty sure Ford didn't recommend this.



I should scan a photo of my heap of crap, I would've killed for one of these.

[bongodriver]

Originally Posted by Osprey

Not with the Spitfire II which is what Kurfurst is talking about. This has a Merlin XII engine designed for 100 only.

I am not sure why Kurfurst agreed with you in the subsequent post unless he forgot which aircraft he was talking about



I agree, I don't have a problem with that, but it's the clearance to use it I'm talking about.

When I was 18 I didn't have clearance to take my engine in my Ford Fiesta 1300S into the red all of the time but when my six was occupied by another kid in an Escort or Golf I pulled the tit and away we went down those country roads like dickheads. After a while I blew the camshaft out of the side of the block, I'm pretty sure Ford didn't recommend this.



I should scan a photo of my heap of crap, I would've killed for one of these.

A fellow country road boy racer........My 2.0L Mk4 cortina was a beast.

[Osprey]

Originally Posted by bongodriver

A fellow country road boy racer........My 2.0L Mk4 cortina was a beast.

Dang! I edited my post from 'Cortina' to 'Escort' because I figured nobody would remember the old monster. Oh yes, I loved the Cortina, my mate had one and Christ - how am I alive today!?! Then there was the Capri 2.8i - that was for the big league

[Osprey]

I read the rest. Firstly, Kurfurst, would you mind not ranting please, your post looks like it comes from a luftwhiner and you've lately managed to curtail that. As such people began to take you more seriously. Your comments about RAF fliers are offensive, when have you ever heard me rant about 109 boost use? My only complaint with your figures is that your graph is 30 kmph faster than any actual test and nobody can account for it - that's why you are in a constant argument and the only people who agree with you are the 109 fliers with an agenda for Spit bashing.

It should ALL be modelled for ALL types, then it's up to the pilot if he breaks it. In the future with scripting (and even now with Banks co-op) you will only get one flight, one life and one engine so fine - break it and die in the channel. Let's concentrate on getting 1C to model this as close to the evidence we have at our disposal as possible and use some damn common sense!

[JtD]

Originally Posted by Osprey

Not with the Spitfire II which is what Kurfurst is talking about. This has a Merlin XII engine designed for 100 only.

Also with the Merlin XII. You would need to modify the automatic boost control so that it would be limited to 12 lb boost when disengaged. IIrc, this was done with reducing the cross section of the bypass.

Originally Posted by 41Sqn_Banks

However I doubt that any Merlin XII had a unrestricted boost cut-out.

I agree, but I'd look at it the other way round - I can't be sure it always had. Do you have the Merlin XII handbook?

[klem]

Originally Posted by JtD

Also with the Merlin XII. You would need to modify the automatic boost control so that it would be limited to 12 lb boost when disengaged. IIrc, this was done with reducing the cross section of the bypass.I agree, but I'd look at it the other way round - I can't be sure it always had. Do you have the Merlin XII handbook?

There appears to have been two methods of bypassing the boost control.

The throttle had a gate, at which the normal max 9lbs boost was produced. At the gate you could shift the throttle to the left then forward to achieve +12.25lbs for takeoff.

Emergency combat boost of +12lbs was also available with the throttle at the normal max position (+9lbs) by pushing forward the red tab we are familiar with froim the Spitfire MkIa/100 octane.

Why there should have been two methods I don't know. I have the attached on my hard drive for the Spitfire MkII, I'll try to find out more if we have a copy of an original Manual at the museum.