ALPHA Halifax Question

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DaveB
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Re: ALPHA Halifax Question

Post by DaveB »

It's not easy Chris although it has been tried. The end result is or has been a custom gauge written in C++ to simulate one stage of supercharging but I've never come across one that's worked with any great success. There are parameters in the aircraft.cfg to stipulate one type or another but that's where the control ends.. normally aspirated or supercharged.

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gannet
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Re: ALPHA Halifax Question

Post by gannet »

Hi,
I hope I haven't got hold of the dodgy end of the stick here, but I think the DC-6/7 from calclassics are turbocharged...at least it says so in the cfg. :cpu: ..as is Manfred Jahn's beautiful Constellation in all it's models. You need to change the settings to fly to altitude. Does supercharging do something else?

Andy.

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DaveB
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Re: ALPHA Halifax Question

Post by DaveB »

Hi Andy :hello:

No mate.. you've not got the wrong end of the stick. Some engines were/are supercharged while others are turbocharged. The end result is similar though the way it gets there isn't the same. FS works with (as default) turbocharged or none turbocharged.. eg, normally aspirated. There are variations on fuel feed to add to the complication but generally.. a piston prop will be either turbo or none turbo.

With some supercharged engines, you can control when the supercharger is used to increase boost (air/fuel) to the engine so it can be switched in or out. Turbo chargers are, to the best of my knowledge, running all the time.. they work by putting a turbine in the exhaust to shove the exhaust fumes back into the cylinder.. recycling the exhaust gasses and unspent fuel if you will. You can adjust various parameters in FS as to the alt max boost will be achieved so at lower alts, there's less turbo effect and at higher alt's the effect is greater.

FS doesn't really do supercharges so you end up having to cheat by making the engine turbocharged or leaving it un-turboed and increasing it's pwr in the cfg :)

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Re: ALPHA Halifax Question

Post by emfrat »

The key to internal combustion engine performance is how much air you can push through the carburettor(s) in a given length of time. Air provides the oxygen that lets the fuel burn, and that is where the power comes from.
On the ground, at sea level, the air is at full atmospheric pressure - a tad under 15 psi. The higher you go, the lower the air pressure - and that means less oxygen. At around about 10,000' the loss is enough to seriously affect the engine performance.
So to get the oxygen back, you increase the pressure by actually pumping the air in, instead of just letting it be drawn in by the vacuum in the cylinders. This is called supercharging.
"Supercharger" refers to mechanically-driven pump, like the one on the front of a 'blower' Bentley, driven off the nose of the crankshaft.
"Turbocharger" refers to a pump driven by a turbine rotating in the exhaust stream.
The Connie engines used a compound system - there was a supercharger with a two speed gearbox, driven by the engine, augmented by an exhaust-driven turbine which recovered slightly more than the horsepower lost in driving the mechanical supercharger.

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