Those of you who were not immediately bored rigid (mea culpa) by my recollections on time spent on the venerable 'Shack' (stimulated by a really great model) might be interested to know the original Shackleton requirement was for its Vipers to be used for two minutes only, as a take-off asset or to accelerate the a/c perceptibly in 'attack' mode!
Shackleton flight development Viper engines were converted from Jindivik Mk.4 Viper Mk.201s making it a worthy companion to the Shackleton - particularly as the original Viper 3 first flew from Bitteswell in the tail of a Lancaster in 1952.
The first Shackleton flight with Vipers was made with WR973 on the 29th January 1965 from Langar, Notts. Some 39 further flights were made mainly from Woodford. Early tests revealled the engine was windmilling backwards so to correct this an air scoop was fitted to the retractable intake door. The engine governor allowed the rpm to creep upwards on a full throttle climb to 10,00ft, which certainly took longer than the two minute Viper rating! Another little fault occurred when the air intake door closed on the engine when it was running at idle, if it had been on full throttle it would probably have eaten the door with undignified consequences!
During August WR973 went on to carry out tropical trials at Wheelus U.S. Air Force base in Libya, provoking the usual USAF question on seeing a Shackleton of "what is it?". Aircraft WR980 carried out cold weather trials in Norway with Flt.Lt. Keith Merit in command. Some time later, icing trials on the non antiiced (!) Viper were flown from Boscombe Down with WR989 under Flt.Lt. Bob Beeson. These were carried out behind the water spraying Canberra, which must have been a bit of fun.
In the early 1960s, the Jet Provost Viper 202s had three main problems in service, which are interesting to relate to the Shackleton. The first was vibration and the second was oil leaking into the front of the compressor, a menace maybe when using compressor air to pressurise a cockpit but ideal for stopping an engine from corroding in the maritime role of the Shackleton.
One problem however really hit the Shackleton's Vipers hard, especially later when they were fitted with an inching button for the throttle to allow the engine to cruise for about 4 hours ( until most of the oil in the small tanks was used up) substantially better than the original two minutes spec? The problem, hot streaks or pencils of flames from the combustion chamber burning the individual turbine nozzle vanes. The Mk.203 uprating made this even worse but the powers that be wouldn't listen to pleas to fit new engines with cast segmented nozzles then being offered as a Mod.
Although the Avro Shackleton Mk III Phase 3 service life was relatively short, some claim wrongly because of the extra weight and stress of the Vipers, it is some comfort to know that at least three aircraft with such engine installations remained preserved. All we need now is a conversion set and a new 1/72nd Mk III.
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No apology necessary as far as I am concerned. These personal experiences are far too valuable NOT to talk about. These is often little time in meetings to share these things but maybe you have enough stories and experiences to book in for a slot of your own at a future meeting? Since moving to Cass Hall, we are trying to make use of the more formal arrangement of the venue and hold talks/demonstrations etc.
Pleased to hear that. I feel we could invite quite a few 'notables' to give talks or do demos! I have a senior US naval buddy coming over from the States next year. His name is Oliver J Semmes, Great, great Grandson of Raphael Semmes, Captain of the CSS Alabama (American Civil War). Oliver and I were on 'opposite sides' in many an exercise where his F9F Panthers were intercepting our Shacks in the north Atlantic. Oliver would speak I'm sure.
That would be wonderful and I'm sure we would be pleased to host him. Kevin co-ordinates all this sort of gubbins so if you throw it across his bows, I'm sure he'll be more than happy to accept. Hopefully, your friend would be over here on a second Wednesday?