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View Full Version : Plz eplain Supercharger in Spits'n hurries to me.


Vengeanze
08-21-2011, 08:42 PM
Are there any? No stages? Auto? How do they work? Anything I have to think about or...?

JG53Frankyboy
08-21-2011, 09:45 PM
all flyable planes , except thevtigermoth, in game have sperchargers.
The Merlin III has a single stage, single speed one. so the pilot has nothing to care about it.....

whoarmongar
08-21-2011, 10:14 PM
In RAF fighters you have a boost gauge, this is your blower, you have a little white marker on the gauge, this is your max safe prolonged use boost marker, you may exceed this boost but not for long periods, saying that iv never killed an engine by overboosting it, but mostly by overheating and overreving engines.

JG53Frankyboy
08-21-2011, 10:30 PM
actually a supercharger is made that an engine can mantain these max boost settings at heights above sealevel (to generalize it ;) )
the maximum height the supercharger able to do so is called full throttle height (FTH) . above this height the boost and poeroutput of the engine drops

mcler002
08-22-2011, 09:51 AM
http://en.wikipedia.org/wiki/Supercharger

Basically its getting more air into the engine!

I use it as a boost to take off and when i fly at high altitudes

Cheers

Vengeanze
08-22-2011, 11:49 AM
Thanks boys.

In IL-2 and PF the supercharger was two-stage and manual so was a bit confused when I read that the British fighters had one and I couldn't find a switch for it.

Some of you talk about boost when talking supercharger. Do you mean that the supercharger only kicks in when Boost Cut-Out is ON?

JG53Frankyboy
08-22-2011, 12:31 PM
no.
as already said here, a supercharger is bringing more air ( oxygen) to the engine. that enables the engine to pruduce more power.
with increasing height , the air become thinner, and till the FTH, a supercharger is able to supply the engine with enough air to mantain the max poweroutput. above that the power drops.

Vengeanze
08-22-2011, 01:06 PM
oki doki. Thank you.

Blackdog_kt
08-22-2011, 03:04 PM
The boost gauge measures relative pressure: zero boost is the ambient air pressure on a standard day at sea level. In other words, it's approximately equivalent to 1 Ata in Luftwaffe instruments or 29.95 inches of mercury for US instruments, which use a scale of absolute values.

So, running at zero boost is actually the maximum, non-supercharged throttle setting. Anything higher than that is extra pressure for more power.

The supercharger "kicks in" when the ambient pressure is not enough to give the intake manifold pressure commanded by the pilot, which is usually on two occasions

a) When commanding more than zero boost at sea level: the ambient pressure is about equal to zero boost on most days/weather conditions, so the supercharger kicks in to give you the extra bit you are trying to achieve.

b) When at more than sea level: whenever the outside pressure is less than the pressure the pilot is trying to achieve, the supercharger provides the extra pressure.

In other words, flying at -2 boost at sea level doesn't need supercharging, but flying at the same -2 boost at 30000ft probably needs supercharging because the outside air is too "thin" to provide even that reduced value.


The difference between RAF aircraft and those of other air forces (despite the different units of measure and the relative nature of the boost scale) is that whatever your chosen boost setting, there is an automatic system that tries to maintain it: as you climb higher and ambient pressure decreases, the supercharger kicks in to provide the "missing" pressure. Your throttle functions more like a "pressure selector" mechanism and an automatic system does the throttling up/down for you to maintain that pressure, along with managing the supercharger.

This doesn't happen with Luftwaffe and US aircraft, where the pilot directly controls the throttle plate on the intake manifold and needs to manually throttle up when climbing to get back the "missing" pressure and throttle back when descending to keep within the limits as ambient pressure rises closer to the ground, in order to maintain the engine operating limits.

However, similar limits for superchargers apply to all of them: above a certain height, even at full throttle the supercharger can't provide every bit of missing pressure to have the engine running at its maximum rated manifold pressure. This is the full throttle height already mentioned by the other people in the thread.

I hope this helps somewhat ;-)