condition levers

[homebrew]

I seem to have forgotten. Do the propeller control levers simply change the andgle of the propellers to maintain a constant rpm, kind of like a piston? Also, what is the function of the condition levers in flight other than continuing to provide fuel? Our plane has a low idle and high idle setting. I'm just starting out on the training and not sure what these settings will achieve. Thanks for your help.

 

[T-Gates]

The condition levers are used to set the idle stop for the engine. In Low Idle on the 1900 they are set to 65% N1, in High Idle, they are set to 72% N1. Increasing them to High Idle will reduce spool up time allowing for more stopping power in reverse and also will reduce the electrical load on the generators when the load is greater than 75%.

Hope this helps,

--03M

 

[EagleRJ]

In a nutshell, the condition levers combine the functions of the propeller control and the mixture. Most condition levers have a governor range near the top of the lever travel that adjusts the prop speed. Some have a flight range and a ground range. Below that are detents for feathering the prop, and at the very bottom, fuel cutoff to shut the engine down (although this is done with seperate levers in some planes).

The propeller speed is usually controlled by a hydraulic governor just like with a constant speed piston engine. That will vary also, depending on if the engine is direct drive (like a Garrett) or is a free turbine (like a P&WC PT6).

 

[GulfPilot]

PT-6 engine installations are typically equipped with 3 engine controls

1) POWER LEVER..adjusts fuel flow rate to the engine..throttle equivalent in a piston airplane when moved behind the flight idle gate, it manually takes control of the prop governor to adjust blade angle for beta- range operations...RPM is then dependant on the position of the CONDITION LEVER

2) PROPELLOR LEVER..adjusts propellor rpm by setting the prop governor to maintain the requested propellor rpm...prop lever on piston it also simultaneously sets the n1 overspeed governor to a specific value slightly above (3% comes to mind) which allows the fuel control to remove fuel from the engine in event the prop governor fails.

3) CONDITION LEVER adjusts engine idle speed by resetting engine idle fuel flow. Once the power levers are advanced beyond the idle speed range of the CONDITION lever, the CONDITION LEVER will have no effect on engine parameters..it also usually has the idle-cutoff function for most pt-6 installations.

SO IN A PT-6 powered airplane so equipped with separate condition levers...the condition lever is connected to the fuel control unit..it controls N-1 rpm by regulating fuel flow.

TPE-331 (garrett, Honeywell Air research)

1) POWER lever...

a) Fuel control (manual fuel valve) for controlling engine power while operating in the flight range (forward of flight idle)

b) Prop pitch control..for selecting beta range operations (ground idle/reverse) aft of flight idle position


2) SPEED LEVER...is connected to the:

a) prop governor, for selecting a requested rpm in the flight range

b) underspeed fuel governor, for selecting a requested rpm when the engine is not being operated in the prop governing mode..I.E. beta range (on the ground only please!!)

TPE 331 engine installations are typically NOT equipped with a separate condition lever, as the "speed lever" performs this function

Hope this helps...many moons have passed since i taught these types.

 

[Beantown]

I just wanted to say that everyone above did an awesome job explaining and answering this question. I wish there were more posts like this one and not so many of people b!tching and threatening. Great jobs guys/gals. -Bean

 

[T-Gates]

I agree!

 

[FracPilot]

Condition levers

In a nutshell, the condition levers combine the functions of the propeller control and the mixture. Most condition levers have a governor range near the top of the lever travel that adjusts the prop speed. Some have a flight range and a ground range. Below that are detents for feathering the prop, and at the very bottom, fuel cutoff to shut the engine down (although this is done with seperate levers in some planes).

It seems to me that the above explains how the Brasilia works - but not most PT6 powered engines. Gulfpilot explained how the controls work in most PT6 equipped airplanes, including the entire King Air line(90 through 1900) and I believe the Starship.