Westland's Wonderful Whirlwinds
On 705 Squadron,during the winter of 1964/65, we flew both WW3 (Wright Cyclone) and WW7 (Alvis Leonides). The main differences have already been discussed. I can add that during night flying the flame from the Mk3 exhaust was at least 2 feet long and a lurid yellow colour. Most disconcerting as one approached the hover. The Mk7 flame was about a foot shorter and a much more efficient violet colour.
On the Mk7, an aircraft destined to spend much of its life at low level over the sea, Westland had positioned the engine air intake on the very lowest part of the nose. Similarly, as only they could, the identical Hydraulic and Engine Idle Cut-Off switches were placed adjacent each other on a sub-panel just below the centre console.
The Bendix cartridge starter is to be seen in post 2242 concealed behind a small blister shaped panel on the front of the engine clamshell doors. This unit had 6 "shots" (IIRC) contained within a revolving magazine that was rotated by means of a lever under the instrument panel. The Navy, in its infinite wisdom, had disconnected this feature fearful that an incorrectly indexed cartridge would blow the nose off. Also, only one cartridge was loaded at a time as it was felt the additional cartridges might "cook off" during flight.
When the cartridge was fired the expanding gasses acted on a piston that, by means of a suitable system of gears and levers, could rotate the engine through about one revolution. If one had got the mixtures and throttle setting correct, and had turned the Mags on, there was every chance that at least one, then eventually all fourteen cylinders would fire up and join the party. Experienced WW pilots took pride in only ever needing one cartridge..................students were different.
If carbon residue built up in the starter cylinder the piston could not move and the excess gas pressure was relieved overboard by rupturing a safety disc. If the safety disc did not blow there was a real danger that the whole unit would be blown off its studs, through the blister panel and lay in a smoking heap on the deck in front of the aircraft. So, the wiser start crew would hold the blister panel open at arms length whilst ensuring that the more sensitive areas of the body were not in line. If necessary the starter was beaten severely with a leather mallet to dislodge any carbon residue. Later, on ARK ROYAL, the stove pipe jockeys and engineers appeared nonplussed by this procedure and I'm sure they thought it was a punishment rather than a recognised maintenance practice.
When I left 705 as a student and went on to qualify on the wonderful new and shiny Wessex Mk5, I thought my Whirlwind days were over. But, a pier head jump in late 1965 saw me joining ARK ROYAL, on her Far East tour, as the junior pilot on the Ship's Flight. XM684 and XM685 were the last AVGAS fuelled aircraft in the fleet and we were the first Ship's Flight to complete a commission with the same aircraft that we started with. (Even though we ran it close). I grew to love the Whirlwind 7 and under the tutilage of POFMAN and a bunch of long suffering but excellent crewmen, I learned more about helicopter flying than I could possibly have done elsewhere.
XM685 now resides in the Newark Air Museum. Whilst in reasonable condition she is lifeless, in the wrong colour scheme and her place in naval history as the last AVGAS powered machine in the fleet goes unremarked.