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To add to Scott's reply, yes, the system is essentially a copy of the "Bendix" system now built by Precision Airmotive. At one time it ws the only non-certified system available, but now Precision also makes a system for experimental aircraft. To the best of my knowledge the experimental system is the same as the certified one - it just doesn't come with a pedigree. The very same engine-driven diaphragm pump can be used, and an electric backup pump is (almost?) always fitted. Since the supplied pressure does not effect fuel flow the electric pump is just that - a backup. Gary Casey
Does the Airflow Performance fuel injection use an engine-powered pump, or does it rely on the electrical pump for fuel delivery all the time? Is there a difference in the principle of operation of this system compared to the standard Lycoming fuel injection system or the Silver Hawk system? Gary Fitzgerald
Gary, The Bendix injection system for smaller Lycomings requires that the throttle body have a minimum fuel pressure to operate through the spider properly. It doesn't care how the minimum pressure is
maintained. Typically, the engine driven provides pressure in excess of the minimum and that help reduce inline vaporization. Typically, an electric pump is also designed to deliver this excess pressure fuel. In these systems, pressure regulation occurs at the pump. In Other systems, pressure may be regulated by regulation at the throttle body by sending excess fuel back to the tank from whence it came. If you are interested, you should study complete aviation fuel systems that you may be able to find on the internet. To answer your question, most fuel system do no rely on non-engine driven pump to maintain the pressure although certain specialized my require such high constant pressure that a separate pump designed to maintain that pressure is used. Scott Krueger |
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