Nimrod Rudder Pedal Movement ?

[XV148]

I am in the process of restoring the flight deck of the Prototype Nimrod XV148. Last month I refitted the rudder bar and pedals to the Prototype and now have just been refitting the rudder limiter. This seems to seriously limit the movement of the pedals and I want to make sure this is set and operating correctly.

Is there any former Nimrod pilot, NLS or ground crew that can provide some advice or input on the amount of movement there should be in the pedals both on the ground and in the air.

Many thanks
Martin

[Wensleydale]

No matter how you set it - it still won't do a U-turn.

[davejb]

Didn't need U-turns
...we just popped the airbrakes and let 'em fly on by...

[oxenos]

It did make stall turns difficult.

[olddog]

As I recall (Slightly clouded by time) The rudder movement was progressively reduced at speeds above 160kts thrugh the Q Feel system and also when the bomb doors were open to prohibit excessive yaw. Therefore on the ground the rudder limiter should be fully withdrawn with the indicator (to the right of the throttle quadrant) showing "out" or "bomb doors open - out" depending on the bomb doors being open or closed. With the bomb doors closed full rudder should be available on the ground.

[OilCan]

almost there..

The 'Q' pot head fed pitot statics to the 'Q' pot for elevator feel and the rudder limiter..(2 seperate buckets)

Below 160 knts the rudder limiter would be fully withdrawn allowing the full +-25 deg of rudder deflection.....unless the bomb doors were open... then the electrical actuator would extend the stopped cone to the 4th stop and limit deflection to about +- 9 deg (this would equate to approx 205 knts)

Above 160 knts the pitot static rudder limiter would progressively reduce deflection to +-4 deg by about 280-300 knts. :8

[XV148]

Many thanks for the responses. I am thinking that the limiter must be set in 'limiting' position as the rudder pedals don't want to move that much. The indicator is half way to the out indicator. There are electrical connections and I am tempted to run some 28v to them to see what happens. The rudder bar and pedestal came from different donor Nimrods and have been joined in XV148.

The pedal positions are working correctly through the rudder trim wheel. As the pedals only move at most two inches each way, there is some work to be done to get the right movement.
Thanks again

[olddog]

You might try the override lever? You should be able to lift and pull back to manually select "out". This would then rveal the full ammount of rudder pedal movement available. As I recall, it requires a fair amount of a pull to overcome the spring pressure but if you can't move the actuator it is probable that something is seized!

[OilCan]

not quite...

The override lever will only overcome the pitot static element of the rudder limiter. If the electrical actuator is extended (ie. Bomb doors open), then the override lever will not overcome it. - a potentially hazardous situation resulting in restricted rudder deflection for the remainder of the flight.

With zero airspeed and the bomb doors closed the stopped cone should be completely withdrawn allowing full unrestricted movement of the restrictor lever arm attached to the rudder layshaft. It sounds to me like the actuator is extended - which is probably how it was when it was removed ie. Bomb doors open. :8

olddog

the 'fair amount of pull' you recall wasn't spring pressure, twas pitot pressure, unless of course there was a siezure in which case it could range from efin difficult to impossible. Solution - more weetabix ;):ok:

[XV148]

What you say makes perfect sense as the bomb doors were indeed open when the donor aircraft was scrapped. When i restored (removed, cleaned and rebolted the unit back to the centre pedestal) I don't recall being able to push the brass coloured cone into the limiter unit, however I wasnt specifically checking that at that time.
I had in the past firmly pushed the bomb door lever back but there was certainly non movement from the white marker. I will try this again although I am guessing that the cone extender will be very stiff/hard to push in. I wonder what will happen if I attach 28v to the actuator ?
I will try over the next few days and let you know the results.
Many thanks
Martin

[CometCrew]

Hi Martin
I'm a volunteer at the de Havilland Aircraft Museum. I'm currently restoring the cockpit of a Comet 1, F-BGNX, which is progressing pretty well, but have the opportunity to restore two other cockpits, one of which is of XK695...one of three ELINT Comet 2's.
Unfortunately, we're missing the Throttle Pedestal and I wondered if you knew the whereabouts of the pedestals from any of the scrapped Nimrods...
Regards
Alan