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appulluk
04-28-2006, 12:10 AM
I've been reading Chuck Yeagers autobio and I believe he mentioned his X1 being in Zero-G at some point and the engine cutting out. It reminded me this seems to happen in a few planes in IL-2, the engine cuts out if I dive or pull too sharply, typically in 1930's biplanes.

But I can't find any information about what causes the engine cut-outs, and more info on zero-g (stuff like charts n' data to help understand it beyond words). Any idea?

appulluk
04-28-2006, 12:10 AM
I've been reading Chuck Yeagers autobio and I believe he mentioned his X1 being in Zero-G at some point and the engine cutting out. It reminded me this seems to happen in a few planes in IL-2, the engine cuts out if I dive or pull too sharply, typically in 1930's biplanes.

But I can't find any information about what causes the engine cut-outs, and more info on zero-g (stuff like charts n' data to help understand it beyond words). Any idea?

rnzoli
04-28-2006, 12:36 AM
for the old planes (e.g., I-153P) , it was the carburettor, which mixed the fuel and air before letting it into the engine cylinders

the carburettor depends on gravity for proper operation and as soon as you get 0 or negative Gs on the engine, the engine is likely to lose power and completely stall due to mixture problems and fuel not getting into the engine

i don't exactly know how they solved it, but I presume that instead of the carburettor, another device was used for preparing the correct mixture of air and fuel, some kind of injector, but let's hear more from the experts

WTE_Galway
04-28-2006, 12:59 AM
the actual reason dependended on the engine

in the case of merlin powered birds like the hurricane it was caused by flooding .. under negative g the carburettor sucked in way to much fuel .. this was cured initially by a diaghram across the float chambers with a restrictor known at the time as "Miss Shilling's orifice". In 1942 an anti-g version of the SU carburetor was fitted. Further improved designs were used as the war progressed.

A good link that discusses this is here:

http://www.spitfiresociety.demon.co.uk/engines.htm


In other cases the problem was fuel starvation rather than flooding .. the engine simply couldn't get fuel under negative G, especially in carburettors with floats a design that that inherently does not like negative g conditions.

The best solution is of course fuel injection like the 109's used.

This problem persists to this day. Many modern GA aircraft are not capable of sustained inverted flight for much the same reasons.

Esel1964
04-28-2006, 01:10 AM
As far as the earlier planes go,it's typically a carb float issue(think the floating bulb in your commode,that controls water flow)it controls a 'needle' that shuts on/off the gas flow.
The same thing will happen in an off-road vehicle climbing an extreme incline.As far as the 4x4's go,you can get an 'all attitude' carb kit to fix this.

To see the float & float valve click below.

http://journeytoforever.org/biofuel_library/z-image/dranefig5-1.jpg

You'll notice if the float goes up,it shuts off the flow of fuel.The float valve(or needle) can be either above or below the float itself,it depends on where the 'needle' connects to the float.Behind the pivot point,means the needle would be on the bottom-as it is in most '40's-'50's American cars.
I'd bet the "all-attitude" technology for 4x's was in some primitive form derived from the aircraft industry.