Keeping the Nation’s Historic Aircraft in the skies
Swordfish W5856 is having a pair of main undercarriage tyres fitted and Chipmunk WX 608 has just had an electrical problem resolved. It had been noticed that W5856 was using a bit more oil than usual. When the normal after flight oily marks were being wiped off the fuselage, a faint spray pattern was noticed at the lower rear corner of the oil cooler and on close inspection a leak was detected. After draining the system the mainly copper oil cooler was removed and taken to the welding bay and cleaned thoroughly inside and out before a repair was attempted. Finding the correct temperature grade of solder was a challenge; too hot and the copper might distort and adjacent soldered seams open up, too cool and it might not adhere well or survive normal operating conditions. The well repaired unit was refitted and the system slowly replenished by pumping in oil from a port close to the base of the engine thus avoiding trapped air pockets.
A walk around W5856 with Andy the flights experienced sheet metal technician afforded a view of some of his recent repairs:
- A trim tab fitted to the fine tube at the rear of the starboard aileron with tiny solid rivets.
- A patch near the oil cooler and 2 panels riveted to either side of the cockpit for radio mods.
- A very fine stainless steel fairing at the upper end of the fwd main undercarriage strut.
- Lying below the oil cooler this fairing and more particularly the strut inside gets pretty contaminated, however the new stainless fairings are sealed top and bottom with modern high tech mastic materials.
After the most recent piston check a ground run was carried out and during the usual magneto drop checks a backfire was noticed. These checks test each of the two ignition systems from magneto to plugs and when the latter were removed a plug from the top (No 1) cylinder was fouled up. The magnetos and plug leads were all tested and fortunately the problem was solved by cleaning the contacts in the distributor cap and replacing the spark plug. W5856 is having a rest before departing North on 9 Sep public appearances at Southport and the following weekend at BAE Brough before the trip home to Somerset. Thanks to RAF Woodvale, BAE Warton and Sherburn-in-Elmet she will stay north rather than returning to/from RNAS Yeovilton thus saving some precious hours.
The Chipmunk has also had an electrical problem as a generator warning light lit up on engine start. Typically this means either the generator on top of the engine or voltage regulator buried down in the cockpit are at fault and both were replaced.
As well as removing the securing bolts and electrical lead there is a cooling duct above the generator which directs air to the commutator and this also had to be dis-connected. Subsequently when bench tested in workshops the voltage regulator was found to be regulating the gennie output at a lower than normal voltage and will be corrected by altering an adjustment screw. The 4 engine mounting bolts were also recently replaced as they reached life expiry. The engine weight was taken by a small hoist and bolts replaced one at a time and after torqueing up the castellated nuts the stainless steel bolts had to be carefully drilled with a fine cobalt bit to take the split pins This work also permitted the rubber bushes in the engine mounts to be inspected and all were found to be in good condition.
The Sea Fury continues to be looked after by the team. The wings are now folded for safety and better use of space and this is easily done by using a cockpit mounted hand hydraulic pump. Work continues in the back offices to return her to flight.
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