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Rudder Diverter Valve


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Was just trying to work out the rudder diverter valve a little. I know it is solenoid operated. But in what position is it when power is taken away from it? (Full pressure or the lower 1275) and what position would it fail in?

If its full pressure is there any thing the crew would need to keep in mind while flying with full rudder pressure?

Thanks for the help in advance.

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with power off it is diverted to 1275. with flaps above 15% you will 1275 and below it will be undiverted to full pressure. It can fail in either position but depending on where it is failing you will get very different readings and actions of the diverter valve.

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Avoid abrupt or full rudder deflection with FLAPS lever positioned 15 percent or greater (high rudder boost) and air speed 210 KIAS or greater.

(Ref.FM 382C-14E sec1 limitations page 5)

To my understanding; the point of having this system (two range of rudder control pressure full and reduced) is:

1- To have full authority of rudder control (full pressure) during T/off and Landing (low speeds).

2- To have reduce authority/less sensitivity during climb/cruise (high speeds).

Hence that high pressure (3,000) if used during high speed leads the rudder control to be very sensitive to induce a big amount of yow for any small input (hi speed/hi pressure) which may leads - if sudden or full rudder deflection is committed - to damage the rudder mechanical linkage or leading the aircraft to inter unintentionally a prohibited manoeuvring zone.

For system to work engineering set up a diverter valve, reducer, transmitter and a switch actuated at 15 % and above on the flap control lever (Hence take off and landing is normally accomplish with flap lever more than 15%).

That 15% switch will close the circuit through (C/B 28v Ess Dc) once flap lever15% or above leading the diverter valve to be energized thus bypassing the reducer and directly providing full system pressure (3,000psi).

Once flap lever is raised up (after takeoff) to less than 15% electrical continuity will be cut-off thus diverter valve will be de-energized leading the hydraulic pressure to be routed through the reducer (1275 psi).

Simply: Any time lever less than 15%, C/B out, or loss of Ess Dc power; will lead the diverter valve to be de-energized = reduce pressure 1275 psi.

Tips during flight: (If failed HIGH) rudder input to be used smoothly and with caution during high speed; (if both failed LOW) charted air minimum control speed to be increased 13 knots.

For only one system failed low, I haven’t got reference of how much speed to be increased.

Edited by tenten
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Yes, SEFEGeorge

Pulling the wing flap control C/B and setting the flap lever to the desired position to provide the proper rudder boost pressure (3000) is a procedure on the FM and was mentioned during the following emergencies and non-standard operation procedures:

1- During loss of flap electrical control system.

2- During manual flap extension.

3- During Flaps up Take-Off.

As well as it is under warning on SMP 777

Quoting: WARNING

Flaps up air minimum control speed charts assume effective rudder boost pressure of 3,000 PSI. To ensure rudder high boost operation, pull the wing flap control circuit breaker and position the flaps control lever to a setting greater than 21 percent.

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“The Airplane Model” is C-130H

The “382C-14E” = is the “Airplane Configuration Code” (maybe the “14E” for sup-modification code)

Oh cool thanks for that.

Thank you to the other replys as well. Its great to be able to find so much information.

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Hint: Rudder diverter button doesn’t have mechanical detent to remain engaged; it should be depressed and held against spring load to provide the full pressure.

Any idea when this feature is to be used??

I can only guess at using it during loss of electrical power to get the higher boost and lower VMCAs, although it would be impractical to hold the button...so that doesn't seem likely. Or is it just used for ground mx?

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  • 3 months later...

is that a newer thing, work on 66's and havent seen or heard of a button to activate the diverter panel or valve. seems kinda weird cause u would need two guys in the cargo door for utility and booster. and during troubleshooting couldnt u just put ur hand on the valve and feel for it opening and closing

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