The
following account of living with the Wright Turbo Compound engine comes
from an anonymous contributor who was obviously intimately involved
with this cantankerous engine. (Although often referred to by its military
designation R-3350, the ultimate version of the engine
which powered the Qantas Super Constellations was more correctly known
by its civil designation of 972TC18-DA3 or just DA3 for
short).
Reminiscences of a
Connie Line Engineer.
- Of standing in the dusk at the end of the Darwin runway and
hearing the first 1049 with tip tanks and radome coming over the
"hump" at full power - all four engines firing well, PRTs glowing
softly in the failing light, gear up - a really magnificent flight
memory. I suspect it was EAC bound for Singapore.
- Flying in the aircraft - the progressive quietness
as each engine was moved into high blower and the props coarsened
out for high altitude cruise. When limitations were subsequently
imposed on high blower (to save impeller bearings) the aircraft
seemed noisier all round.
- The never ending engine changes - on and on, culminating
with the disastrous Queen Mother's flight, (VH-EAA March 1958) where
at least three of the four engines were changed. Tales of changing
engines to the extent that they even refitted a u/s one by mistake,
because there were so many on the tarmac that day in engine stands.
- Engines starting up after inhibiting - flames and
smoke everywhere, even flame extending to singe the horizontal stabiliser
de-icer boots. The never ending use of vanadium pentoxide for inhibiting
cylinders.
- Dismay at seeing a newly overhauled DA3 returned
one week later with a broken front master rod - bell mouthed cylinders,
disassembly by crow bar and oxy cutting torch - all that effort
wasted.
- Grease and oil everywhere, the stench of cold degreaser
still reminds me of those engines. Grease from the propellor hub
had to be scooped out by hand. The foreman who drove apprentices
to distraction with the endless cleaning of oil trays and buckets.
Oil even blowing around when emptying the huge oil trays. Rag, more
rag and yet more rag to clean up. Looking for oil leaks - wash down
with white spirit and then run the engine - how any oil leaks were
ever found was a miracle, let alone a cracked cylinder base.
- The engine that came in with a PRT wheel in
zone 2 - it had cut clean through the chrome moly engine support
mount - supposedly at 14,000rpm. Four drilled PRT blades would break
out and shear off the remaining PRT blades.
- Tedious hours spent lining up exhaust ball joints
and still they would leak.
- Synchronising the dual fuel injection pumps, fiddling
with the vernier adjustment at night, torch in hand. Admonition
never to put your hand in front of the injectors while they were
being tested - and gruesome tales by those who did.
- The repeated timing of the magneto, and that wretched
device the "Time Rite" that seemed to have a mind of its own when
it came to timing the engine - the simple box and three lights seemed
far more effective.
- Of "Rocket", turbanned like a pirate, setting the
valve clearances - rocker box caps off - start from the top or start
from the bottom, you still got covered in oil.
- Tall tales and true of Tony and Al who could reputedly
change cabin superchargers single handed.
- Special tools of every shape, size and description
to get at cylinder hold down bolts and nuts - especially when PAL
nuts replaced lockwiring - and even some form of plate that was
punched over the hexagon surface to ensure cylinders were held down
tight. Lockwiring of cylinder bolts was enough to send you demented.
- Of the DC-4 EBK returning from overseas, bumping
the nosewheel at each corner by braking hard to get steerage. When
we opened the aft cargo door there were two Canberra Avon engines,
one u/s R2000 from the DC-4 and yet another dud DA3 to be winched
out and sent for overhaul. I sometimes felt the main purpose of
the DC-4 was to move DA3s about the world after Constellations.
- The endless search for cylinder head cracks - God
knows how many hours were spent minutely examining cylinder heads
for cracks. The limits on fins cracking and missing must have employed
Tech Officers for years.
- Scooping seagull remains from the carburettor intake
- all legs and eggs! The stench of cooked birds, feathers and bits
and pieces all round the cylinder baffles - what a task to remove
them in the cold and damp of a winters morning.
- Engine runs at full power - the noise and vibration
was unspeakable - the engine checks, magnetos, prop synch and that
device of the devil, the ignition analyser with the myriad patterns
to memorise - HT failure, LT failure, front bank, aft bank - on
and on.
- Of the aircraft that shed a propellor blade in
the USA and had to land at an Air Force Base - the investigation
and how the miscreant prop did not hit the fuselage or adjacent
engine. (VH-EAO August 1959).
- Feather checks, fine, coarse, reverse - the hum
of the Curtiss prop motor and "whack" of the prop brake as it went
in and out.
- Props hung around the hangar wall off large studs
like sentinels awaiting duty, one blade vertical.
- The ceaseless moving of engine rostrums - noise
being moved around - how anyone missed getting a hernia is beyond
belief, oily, greasy, heaving into place. Few wheels ever went round
- just skittered over the concrete tarmac.
- Of five foot bars to undo the oil filters in
zone 2 after the engine run - more dismay when the filter was
full of bronze and steel particles - another engine change for sure
- run the engine and hope it would come clean, but it never did.
The rain would start, the afternoon shift would be sent to the terminal
and wearily the engine change would go on.
- The intricacies of the PR-58E5 carburettor to understand,
with fuel injection- coloring in fuel head power enrichment valves,
idle circuits, fuel return circuits. George had mastered it and
so had every apprentice better master it. Of trying to concentrate
on a summers afternoon in the Hangar 20 tech school while some "experts"
were running DA3s at full power for a pressurisation check.
- Trying to understand BMEP, specific fuel consumption,
fluid couplings, compound gearing of PRTs back to the crankshaft
- a totally black art.
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