10.05.2008, 08:11
The presence of an accelerator pump does not necessarily mean the engine will produce significant amounts of smoke every time the throttle is opened quickly. A properly tuned engine may not produce any discernible smoke, as the accelerator pump charge is burned completely. Only an improperly sized accelerator pump aperture will create large amounts of smoke, along with stumbling on acceleration and possibly fouled plugs. Metering is a function of the carburetor design, and some are more efficient than others.
Fuel injection systems, including the mechanical type employed in many WWII-era aircraft, can be tuned more efficiently still. Running extremely high fuel pressures (~500psi or more), these systems can be exceptionally efficient and are calibrated to precisely meter the fuel to the engine in all operating conditions. Injected engines are even less likely than carbuteted engines to exhibit significant amounts of smoke if in proper tune.
As I have stated before, a boost system MAY (depending upon the type of boost it provides) produce smoke along with increased power, but this will come along with other, likely detrimental, effects on the engine. To make a blanket statement suggesting that all fuel systems on all aviation engines produce similar amounts of unburned fuel smoke in similar operating conditions is vastly oversimplifying the situation.
Fuel injection systems, including the mechanical type employed in many WWII-era aircraft, can be tuned more efficiently still. Running extremely high fuel pressures (~500psi or more), these systems can be exceptionally efficient and are calibrated to precisely meter the fuel to the engine in all operating conditions. Injected engines are even less likely than carbuteted engines to exhibit significant amounts of smoke if in proper tune.
As I have stated before, a boost system MAY (depending upon the type of boost it provides) produce smoke along with increased power, but this will come along with other, likely detrimental, effects on the engine. To make a blanket statement suggesting that all fuel systems on all aviation engines produce similar amounts of unburned fuel smoke in similar operating conditions is vastly oversimplifying the situation.