Rotorcraft Engine Controls 1

[Schuyler]

I am trying to understand engine controls (gain and phase margin) as it relates to rotorcraft engine airframe compatability. Can anyone recommend a basic easy to read resource for this (i.e., engine controls for dummies).

 

[Sparweb]

Shapiro, Principles of Helicopter Engineering, 1956. I admit, it's old, but half of the heli's flying today were designed in the stone age anyway...

Steven Fahey, CET

 

[nlappos]

A great deal of literature is available in the American Helicopter Society forum proceedings. There are some key technical problems with engine/rotor dynamics. The biggest is stability in the 2 Hz regime, where the engine control could cause rotor/drivetrain resonant response. The second major area is basic response to power application, which is at the near-DC response end. What type of helo and what type of engine are you studying?

 

[Schuyler]

Can someone please provide a basic explanation of a turbine engine surge and stall. The specific application is for Rotorcraft (Turbo-Shaft Engines. What are the specific differences between and surge and stall? What causes them? How do you prevent them? Does this happen only in the compressor area of the engine? Thanks For Your Help

 

[karlbamforth]

In very simple terms.
Stall is what happens when the compressor blades stall, similar to an aeroplane wing, often caused by ingesting something.
Surge is what happens immediately after a severe stall condition, the high pressure air downstream of the compressor surges forwards. In an axial flow type engine the compressor is normally destroyed as the air surges forwards, some of the resulting debris will then be reingested and generally destroy the hot section of the engine. I have seen this happen at close quarters on a military jet running at high power at night. Quite spectacular, loud bang, sheets of flame coming from both intake and exhaust, followed by silence disturbed only by the noise of aircrew running away.