cosync
Posts: 635
Joined: Sat Nov 17, 2001 7:53 pm

Jetranger Governer RPM Switch

Sun Mar 17, 2002 12:53 pm

what does the governer RPM switch do? i know how the collective works and stuff but just dont understnad that switch?
 
Notar520AC
Posts: 1517
Joined: Sat Jul 21, 2001 6:53 am

RE: Jetranger Governer RPM Switch

Sun Mar 17, 2002 1:29 pm

I have never used the thing in any helicopter, but I from playing with it in the sim it looks like it just inches the main rotor RPM up and down in small incraments. Gee- you guys have a lot of questions I'm gonna have to ask my instructor!
BMW - The Ultimate Driving Machine
 
cosync
Posts: 635
Joined: Sat Nov 17, 2001 7:53 pm

RE: Jetranger Governer RPM Switch

Sun Mar 17, 2002 8:02 pm

well u know what i dont understand.
i dont undersand how the rotor RPM and the engine RPM can be diferent. there both the one shaft. like the 2 needles on the rpm gauge is what im talking about.
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Jetranger Governer RPM Switch

Mon Mar 18, 2002 6:30 pm

The RR Allison 250 is a double-spool engine so the second (engine) RPM is probably the core (high pressure compressor/turbine) RPM.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
cosync
Posts: 635
Joined: Sat Nov 17, 2001 7:53 pm

RE: Jetranger Governer RPM Switch

Mon Mar 18, 2002 6:36 pm

oh ok thats where my knowledge stops. no idea what double spool means
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Jetranger Governer RPM Switch

Mon Mar 18, 2002 7:32 pm

Time to hit some jet engine literature then!  Smile

In a single spool turboshaft engine, the compressor, driveshaft and turbine are all on one axle. In a dual spool, the low pressure compressor, low pressure turbine and driveshaft share one axle while the high pressure turbine and high pressure compressor are on a second one.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
cosync
Posts: 635
Joined: Sat Nov 17, 2001 7:53 pm

RE: Jetranger Governer RPM Switch

Mon Mar 18, 2002 7:53 pm

ahhh i see. pretty simple. so thats what the 2 needles are. so in a robinson R22 there would only be one needle.
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Jetranger Governer RPM Switch

Mon Mar 18, 2002 9:41 pm

Well, unless you have a separate indication since the engine isn't connected to the rotor at all times. Then there's manifold pressure or whatever they use to set the power...  Smile

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
UPS763
Posts: 195
Joined: Wed Nov 14, 2001 7:00 am

RE: Jetranger Governer RPM Switch

Mon Mar 25, 2002 8:57 am

Cosync,
In the R22 there are two needles, Engine and Rotor tach. In normal flight they should be joined at all times and operate at 97-104%. When practicing autos, throttle chops, etc., the trottle is complettley rollled of until you flare. So the needles are not joined during those procedures. When the engine and rotor are not joined the rotor speed has a range of 90%-110%. Anything below 80% your blades stall and thats all she wrote.

Matt

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