Staines, UK 1972, June 18th.
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The tailplane (in the days before we called them horizontal stabilizers) was moved by 3 hydraulic jacks in response to pitch (or a/p) inputs. The "elevator" wasn't really an elevator at all, it was a massive geared tab moved by a simple mechanical linkage to the stab. I suspect what you encountered was a failure of that linkage, which would indeed allow the tab to float freely.
PS I wrote "our" because I worked at de Havilland at the time, not because I designed the system.
Join Date: Jan 1999
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Post #59
Wow! Takes me back 45 years! Excellent link. Couple of points:
- at the bottom of each HSI is the 'drift shutter'; when switched right the caption was blank and in heading mode the autopilot/flight director would fly the heading demanded by the heading bug. When selected left the caption AUTO appeared and Doppler drift was applied. The APFD would then fly the track demanded by the heading bug.
- the moving map (Doppler driven) was never used because it was too unreliable; IIRC the original design featured a pen to physically draw a record of the track actually flown on the map.
- the T3 had an extra yaw damper to compensate for the reduced directional stability caused by the lengthened forward fuselage; flight with dampers off was demo'd during training - very unsettling!
- the boost engine reliability was poor - fortunately it was only needed occasionally - high aircraft weight on hot days or on short or contaminated runways (snow/slush).
The hydraulic systems were labelled green, blue & yellow. When needing to go back to the cabin to use the toilet the pilots would refer to 'just going back to offload the yellow hydraulics'.
Wow! Takes me back 45 years! Excellent link. Couple of points:
- at the bottom of each HSI is the 'drift shutter'; when switched right the caption was blank and in heading mode the autopilot/flight director would fly the heading demanded by the heading bug. When selected left the caption AUTO appeared and Doppler drift was applied. The APFD would then fly the track demanded by the heading bug.
- the moving map (Doppler driven) was never used because it was too unreliable; IIRC the original design featured a pen to physically draw a record of the track actually flown on the map.
- the T3 had an extra yaw damper to compensate for the reduced directional stability caused by the lengthened forward fuselage; flight with dampers off was demo'd during training - very unsettling!
- the boost engine reliability was poor - fortunately it was only needed occasionally - high aircraft weight on hot days or on short or contaminated runways (snow/slush).
Yes the "all-flying" tailplane, like the other primary controls, was driven by three hydraulic jacks, one for each hydraulic system.
Discorde
I baulked at reading the link at the detail and shear complexity of the Trident. It certainly was a great but complicated aircraft.
I'm surprised nowadays that I understood it all let alone knew how to tweak the systems like the cabin on a GIB or GLA descent with brakes and 10500 reverse.
Doesn't mention the sixpence/half a crown feeling at Nicosia with the approach lights fast approaching on take off though.
I'm surprised nowadays that I understood it all let alone knew how to tweak the systems like the cabin on a GIB or GLA descent with brakes and 10500 reverse.
Doesn't mention the sixpence/half a crown feeling at Nicosia with the approach lights fast approaching on take off though.
I remember it’s nickname was the gripper due presumably to the takeoff performance you are referring to blind pew. I mainly flew Boeings with such a surplus of performance that a full power takeoff was unusual. I did experience a jumpseat takeoff in a trident from Luton of all places and remember getting a very good view of the end of the runway. I seem to remember someone had also written ‚fastest over the threshold‘ on the back of the cockpit door. So performance overall seems to have been interesting. I do however associate it with happy holiday memories as a child mainly going to Geneva on skiing trips.
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It certainly was a great but complicated aircraft.
I remember it’s nickname was the gripper due presumably to the takeoff performance
'You're witnessing de Havilland's attempt at the world land speed record.'