1960s Mk 3 AH

[seven g]

Can anyone remember the direction and magnitude of the acceleration errors with the Mk 3 AH in early jets (T.11?). I seem to remember they were largely corrected in the Mk 4 AH fitted to the JP, although acceleration in that aircraft wasn't much to talk about.

[57mm]

Sounds like a question for an A1!

[Yellow Sun]

Originally Posted by 57mm

Sounds like a question for an A1!

An A1 could explain it with his hands in his pockets.

😀YS

[aw ditor]

The T11 (Vampire) wasn't exactly a rocket ship either., on the rare hot Summers day in Lincolnshire. Especially with a heavyweight QFI in the other seat who's diet consisted largely of Holes Ales' (Newark) Ltd.

[Chugalug2]

Originally Posted by seven g

Can anyone remember the direction and magnitude of the acceleration errors with the Mk 3 AH in early jets (T.11?). I seem to remember they were largely corrected in the Mk 4 AH fitted to the JP, although acceleration in that aircraft wasn't much to talk about.

My Ground School notes from 1961/2 at RAFC cover the Mk3 AH even though our course was the first to train on the JP. I quote from the relative paras :-

Acceleration Errors These, caused by inertia in pitch erection mercury switch and pendulosity of gyro unit, are not compensated for but should not exceed a false nose up indication of more than 2.5 degrees caused by the pitch erection switch. The pendulosity causes a slight roll error to port not exceeding 2 degrees..

The Mk 3B acceleration errors were less than the Mk3 due to increased gyro pendulosity. The Mk 3C was the same as the 3B but incorporated an ON/OFF flag.

None of them had an Upper Sling Swivel, but the .303 SMLE padlocked to my bed did!

[seven g]

Thanks Chug. Sounds about what I remembered. Younger generation can't believe it!

[SpazSinbad]

Trainee RAN FAA & RAAF Vampire Pilots had FoG (fear of god) blasted into them about the Artificial Horizon PRECESSION during take off acceleration as we called it in dem tymes. However one Midshipman trainee died at PEARCE during his first night solo take off as seen in this report.
“RAAF Series 2 - ADF Aircraft Serial Numbers | A78, A79 and N6. De Havilland DH-100/DH-115 RAAF / RAN Vampire | A79-653 4175 T.35 According to aircraft status card aircraft "crashed, exploded and burned whilst on a training flight" 21/01/66 1AFTS Pearce WA.” :
ADF-Serials Vampire
“Briefly the story is that due to the known precession of the Vampire Attitude Indicator during the Takeoff Run, it was known to allow for that by — after liftoff at night — to fly with about a five degree to port attitude, with nose slightly higher than usual for climb. This overrode the precession which — if followed — would cause the aircraft to fly as Hammond did — to the right and down. All Vampire students (pretending IMC/night) were shown this effect by flying towards the hills (with instructor) during the day after an instrument T/O on RW36. The Vampire aircraft all pointed towards to the same black spot in the hills to the east of airfield (if following AI after T/O).”