09/02/2003

Pressure Carburetors

Delphi Engineering in conjunction with others did a complete test and report
on a pre 1910 Curtis Engine supplied to the Wright Brothers and production
used in their flyers into the teens. 

It was fuel injection.  Not carbureted - Fuel Injected. 

On the production engine from 1906 thru 1912.   OBTW, heard of the discussion 
of piston ports - you know, those holes at the bottom of the cylinder 
uncovered by the piston near BDC.  

And, according the history of flight by NASA the Injection Carburetor aka 
Pressure Carburetor -development was started by the British in Farnsbourgh in 
1918. 

This "carburetor" used an aeroid bellows to vary the fuel thru a pressure fed
nozzle.  Ignore the fact that if the Super engineers had invented it, it would
very closely resemble a controlled fuel injection. 

Now a little note from the history of the spitfire and its rolls royce
engines.

"Carburetor design

One of the great problems as discerned by pilots was the tendency for the
carburetted engine to cut out under negative 'g'. Luftwaffe pilots learned to
escape by simply pushing the nose of their aircraft down into a dive, as their
fuel- injected engines did not cut out under these circumstances. By 1941 Miss
Tilly Shilling in Farnborough had developed a partial cure for the problem. A
diaphragm across the float chambers with a calibrated hole allowed negative
'g' manouvres, and was fitted as standard from March 1941. Sustained zero 'g'
manouvres were not sorted out until somewhat later. In 1942 an anti-g version
of the SU carburetor was fitted to single and two-stage Merlins. 1943 saw the
introduction of the Bendix-Stromburg carburetor which injected fuel at 5psi
through a nozzle direct into the supercharger and was fitted to the Merlins
66, 70, 76, 77, and 85. The final development was the SU injection carburetor
which injected fuel into the supercharger using a fuel pump driven as a
function of crankshaft speed and engine pressures, which was fitted to the 100
series Merlins."

Note that the Bendix-Stromburg Injection Carburetor was made by dufass non
Kraut american engineers and by this time in the war was standard equipment
for almost all american engines produced.  So much for what allied pilots
would toss the kraut salad for fuel injection - but hey - don't let the facts
of history interfere with your later day never been there done that version of
what really happened.

And that all packard built Rolls Royce Merlin ( You do know they built more
than RR did didn't you? ) starting with the first one in around 1943 had
Injection or Pressure Carburetors.  Production.  Right in the parts bins next
to the Nordon Bombsight and the American Made British Engineered German Code
Machine decoders.

"The development of high-altitude bombers required the development of an
engine with a higher full-throttle height. Rather than move to turbochargers,
Hooker suggested adding two superchargers in series. Since a high altitude
supercharger of the right size had already been developed, the output from the
Rolls-Royce Vulture supercharger was simply fed into the supercharger of a
Merlin 46. The only modification required was the incorporation of a cooling
stage after the two supercharger stages to prevent premature fuel detonation
during compression in the cylinders. The new engine, the Merlin 60, had a
full-throttle height of nearly 30 000 feet. A redesign changed the
supercharger gearing and introduced a 2-piece cylinder block to produce the
Merlin 61. This engine produced spectacular effects when fitted to a Spitfire.
Although intended for the Mark VIII, it was possible to fit it to the Mark V
airframe, and this became the Spitfire Mark IX/XVI series. The extra cooling
necessary became evident by the enlarged radiator under the left wing."

Intercooled non turbo two stage supercharging with intercooling that actually
flew during WWII.