Living with the DA3.
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
- 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
- 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
- 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
- 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.
Rocket was subsequently
identified as Peter John Wilson (9 Feb 1934 - 16 Dec 2009)
Mean Effective Pressure
the engineer known as "Rocket".
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