Boost Cut Out

[=FI=Murph]

I would appreciate some advise on when to use boost cut out in both the Spit and Hurri. When should it not be used? Can it be used constantly as long as rpms and temps are kept within proper limits?

[Baffin]

The control is actually a boost cutout Override feature. In the Rolls Royce (RR) Merlins, the boost is automatically managed by the engine in order to keep the Boost pressure (Manifold Pressure) within limits. RR realized that in an emergency, the pilot must be able to override the automatic feature to apply unrestricted, maximum power. The boost cutout override does exactly that.

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Excerpt from: OP2GvSAPINST_3710.1B.pdf (You may download this using any search engine)

*Use of +12lb/sqin Boost: AP1590B/J2-W

1. Requires the use of 100 Octane Fuel.
2. Will maintain +12 PSI boost to about 10k feet. Boost will drop above this height. Max (unregulated) boost = +17PSI
Overboost Note
The Boost Control Cut-Out enables higher boost pressures. The use, in an emergency, of this high boost pressure is a definite overload condition on the engine and therefore all occasions on which it is essential to make use of this +12lb./sq.in. must be reported by the pilot and recorded in the engine log book so that the engineer officer may be able to assess the reduction in life between overhauls and the need for special inspections.

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IL-2 Cliffs of Dover unrealistically allows the use of BCO with varying negative impact. Sometimes it will lead to engine failure/overheat, and sometimes it seems to work all day long. Your application depends on how realistically you want to operate the engine. The above information is how the BoB pilots had to do it, not how you have to in CLoD. Different combinations of prop & power are used depending on speed & altitude. Enjoy!

[ATAG_Monkeynut]

This thread from the other day is not quite on topic, but it does explain when I usually use it in clod:

http://theairtacticalassaultgroup.com/forum/showthread.php?t=11843

As Fidget said, the way it works in game is not quite like real life. There of plenty of pilot memoirs that say they pretty much flew with it on all the time and didnt have the problems we'd have in clod. Although I'm sure they probably seriously shortened the engine life in their aircraft!

[=FI=Murph]

It says under 10K ft- does this mean I should avoid using it above that altitude?

[Baffin]

In real life, it's an emergency procedure. In CLoD, it's a "Feature". Use it the way you want to.

[ATAG_Septic]

It says under 10K ft- does this mean I should avoid using it above that altitude?

Hi Murph,

It's not so much a need to avoid using it, it's that there's no benefit to using it much higher. I can't remember at what height it becomes ineffective but you can check your boost gauge for effect.

Septic.

[=FI=Murph]

It seems like lower RPMs i.e., courser pitch setting, would be more important than boost at higher altitudes for getting more speed. Is that correct? Is it modeled that way in game?

[Bounder!]

I always think that's a bit of a fallacy tbh Murph and can't say I've seen performance chats for CSP that show lower rpms = greater top speed, quite the opposite. Use lower rpms to keep the engine cool and more efficient but in combat use recommended combat settings if temps allow (2800-3000rpms 6/12lbs boost). Regarding altitude, manifold pressure will drop as you gain altitude and you'll find over 10,000ft you will get lower than 12lbs boost - so you can have boost cut out engaged over 10,000ft but you wont get some/any benefit as you go higher.

[edit] If you are interested in how boost cut out works, <see this post> (http://theairtacticalassaultgroup.com/forum/showthread.php?t=7529) on the ATAG forums.
Getting the most out of your Spitfire/Hurricane in pure top speed terms is a balance between the greatest throttle + rpm setting you can run vs how much you can close your radiator (all without exploding your engine due to overheating!).

[ATAG_Lewis]

I don't use it at all.....When I first started flying CLOD I didn't want to complicate things by using it and figured I would get use to flying without overheating to start with and then introduce the 'Boost Cut-Out' when I was more confident that I had sussed out the basics....However in this process I started getting kills....and then more kills.....and then I got to the point where I never use it at all..because I didn't feel I was going to get anything more from it

I guess I should start using it now and then....to maximise my aircrafts potential....

I am just saying that its not the be all and end all...you can fly perfectly well and clock up those kills without using it at all if you like...

[dburne]

I have gotten to where I use the boost cutout in mine, currently flying the Hurricane in Hun in the Sun's campaigns.

If I am about to engage some fast planes, like 109's or 110's, I will go ahead and activate it and use it during combat, I am just careful not to exceed the 100% throttle setting until I really do need it. I find it comes in handy at certain times.

As long as I don't over abuse it, it has not burned me.

[Nightdare]

May I make a small Hijack?

At current I got a hotkey on my throttle to enable BCO
But after enabling to go 110% throttle, I need to hair the throttle back and push forward again
I'd prefer to simply have 100% throttle on the lever, and the added 10% on a hotkey, but the ingame hotkey menu (it appears there are several
keys for BCO/Boost throttle/Full throttle/WEP) doesn't seem to agree with my idea

How to map accordingly?

[Baffin]

May I make a small Hijack?

At current I got a hotkey on my throttle to enable BCO
But after enabling to go 110% throttle, I need to hair the throttle back and push forward again
I'd prefer to simply have 100% throttle on the lever, and the added 10% on a hotkey, but the ingame hotkey menu (it appears there are several
keys for BCO/Boost throttle/Full throttle/WEP) doesn't seem to agree with my idea

How to map accordingly?

The BCO is controlled by the throttle lever in the real airplanes. There is no switch, simply the red "gate" to prevent inadvertent use by the pilot. The system you have is accurate... you have to push "through the gate" to bypass boost protection.

Some throttle controller software allows programming the BCO as the throttle passes a certain point. (Sort of like an afterburner detent) It depends on your controller...

[Nightdare]

I'm aware of that, but my throttle doesn't have an afterburner notch
would've loved a real life action, but will have to settle for the next best thing