Spit Mk1 Boost?

[=XIII=Wedge]

So given that we currently have an earlier Spitfire using only 87 octane fuel:-


With the ABC enabled (normal situation)

• The maximum boost obtainable will be +6.25 lbs.
• Once set the selected boost (datum) will be maintained regardless of changes in altitude up to the rated altitude.
• Above rated altitude the pressure will drop off, but the datum point will remain the same.
• Pilot workload is reduced and there is no risk of overboosting the engine.

With the ABC disabled (done by operating the cutout)

• The maximum boost obtainable would be +17 lbs @ sea level.
• Any rise above + 6.25 would have disasterous impact on the engine due to pre-ignition of the fuel.
• Provided that the pilot retarded the throttle they would have manual control of the boost, but would have to be careful not to overboost the engine.
• The indicated boost pressure would change as the altitude changed.

Assuming that this is a correct description then from a game design point of view their are a few options.

1. The operation of the cutout would only be of value if the game simulated failures to the ABC unit either through the damage model or the physical weathering setting.
2. If this was not the case then the cutout option could be removed (Only the sadistic would take pleasure from using the cut-out to intentionally overboost a Merlin)

If any of my assumptions are incorrect then please let me know.

Does this seem like a reasonable analysis of the issue?

[Osprey]

I feel more clever already

[TomcatViP]

Really ?

If you get 6.25 op. WHy wld you hve 17 then ?

Just a reminder 6.25x2=12.5
6.25x3 = 18.75

So nearly two third of Merlin "power" (let's say for a second that boost ctr linearly the available power) was spared from the normal eng op that was used to qualified the type in the RAF FC !

What do you think they tried to spare Sidney pride ?

What is to be sure is that I m getting old with that endless debate as much as if the time on the CoD forum was highly boosted !!

[Osprey]

With every post of yours the more I realise that you know nothing about the subject. He plainly says that you would fatally damage the engine by going up to that rating. Furthermore the ABC job is to stop that from happening but you can disable it in order to achieve some increased power for a short period (WEP) or manage your own boost pressures.

Did I understand that correctly Wedge?

[TomcatViP]

I think you are the one that do my dear.

If you think that the FC was modifying the Merlin's engines like a car tuner will do, tht is a real problem.

As I have alrdy said it's not my personal thinking that prevail in my word. You are wrong on the all line. If I had a personal idea on the subject I won't bother other with my own thinking.

I think you 100octer and 17lber shld read this with much attention and stop lobbying every forum that deal with the Spitfire and smokes any discussions with insult and name calling etc.. etc..;

As I alrdy said, this theory does not makes any sense either on historical or mechanical grounds.

If there was a switch for emergency boost right on summer 1940 it certainly wasn't for a 17lb boost that even in 1944 still posed some problem.

Oh yeah let me guess, if you unfold your SpitPufPuff.com doc you certainly are already with injected nitroglycerin and so on at this same date.

The fact is that guys like you are bitching so much on every forum with YOUR idea of the spit (not the real one) that no sim devs can makes a FM with serenity.

What is senseless is that if such is done, it would be a really good plane to fly and fight.

By the way stop bad mouthing on me Osprey that's getting pretty boring. You don't know me. Thx

[pupo162]

Originally Posted by TomcatViP

I think you are the one that do my dear.

If you think that the FC was modifying the Merlin's engines like a car tuner will do, tht is a real problem.

As I have alrdy said it's not my personal thinking that prevail in my word. You are wrong on the all line. If I had a personal idea on the subject I won't bother other with my own thinking.

I think you 100octer and 17lber shld read this with much attention and stop lobbying every forum that deal with the Spitfire and smokes any discussions with insult and name calling etc.. etc..;

As I alrdy said, this theory does not makes any sense either on historical or mechanical grounds.

If there was a switch for emergency boost right on summer 1940 it certainly wasn't for a 17lb boost that even in 1944 still posed some problem.

Oh yeah let me guess, if you unfold your SpitPufPuff.com doc you certainly are already with injected nitroglycerin and so on at this same date.

The fact is that guys like you are bitching so much on every forum with YOUR idea of the spit (not the real one) that no sim devs can makes a FM with serenity.

What is senseless is that if such is done, it would be a really good plane to fly and fight.

By the way stop bad mouthing on me Osprey that's getting pretty boring. You don't know me. Thx

you clearly missed the point.

the plane could go to 17+ boost, but would go BOOOM if they tried to go that way. Im sure eventually they got aroudn that problem and managed better engines who could go more than +6.5.

Even myself who thinks of a pittie as a uselless kite, can get the fair point wedge is making.

[TomcatViP]

Believe me or not but military services do test planes to remove any Go&Boom features.

If there was such a lever, it wld be instantly sealed, locked and patched with every possible red tapes

Bench test is not Flight test that is no Op Tests that are not them self Op limits. And I did it short.

[SEE]

Originally Posted by =XIII=Wedge

So given that we currently have an earlier Spitfire using only 87 octane fuel:-


With the ABC enabled (normal situation)

• The maximum boost obtainable will be +6.25 lbs.
• Once set the selected boost (datum) will be maintained regardless of changes in altitude up to the rated altitude.
• Above rated altitude the pressure will drop off, but the datum point will remain the same.
• Pilot workload is reduced and there is no risk of overboosting the engine.

With the ABC disabled (done by operating the cutout)

• The maximum boost obtainable would be +17 lbs @ sea level.
• Any rise above + 6.25 would have disasterous impact on the engine due to pre-ignition of the fuel.
• Provided that the pilot retarded the throttle they would have manual control of the boost, but would have to be careful not to overboost the engine.
• The indicated boost pressure would change as the altitude changed.

Thanks guys, just one qestion. At alt 17K and above, the manifold pressure in Clods Spit Mk1 drops significantly (less than 2 Ibs per Sq.in.) - full throttle - straight and level - The boost cut out has no effect as pointed out earlier in the thread. So, based on the above - this appears to be incorrect for that altitude?

[Crumpp]

The maximum boost obtainable would be +17 lbs @ sea level.

The maximum boost is only +12lbs at sea level in emergency override in the Spitfire Mk I.

That is all the Merlin II and III were capable of handling and that was a definite over boosting of the engine.

[Skoshi Tiger]

Although not Merlin engines, I assume these engines were running above their maximum allowed boost!

http://www.youtube.com/watch?v=aUkXriHjQeI

http://www.youtube.com/watch?v=vq5cj...ture=fvwp&NR=1

Well at least it put a smile on my dial!

Cheers!