---------------------------------------------------------- RV7-List Digest Archive --- Total Messages Posted Mon 05/14/07: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:56 AM - Re: Initial biuld decisions (J. Brunke) 2. 09:01 AM - Re: Initial biuld decisions (Hinde, Frank George (Corvallis)) ________________________________ Message 1 _____________________________________ Time: 06:56:13 AM PST US From: "J. Brunke" Subject: Re: RV7-List: Initial biuld decisions Dear Carl, In your well written response you wrote: > there is some complexity, higher fuel line pressures, need for a return > fuel line to a tank and more expensive fuel selector, more difficult hot > starts. In my search for engines that started at Sun and Fun, I specifically asked the fuel return question to most of the engine sales people. Aerosport and Mattituck both said a return line is not needed in their fuel injection systems. I can't remember the response of the other engine groups, but reducing complexity is probably better for sales. I always assumed one would be required also. That eliminates some of the complexity issue and relief for me since I had already sealed up my tanks. That also means a less expensive fuel selector, so that might bring the injection system somewhat closer in price to the carb system. As for the hot start issue that could be a problem. Lycoming is now selling non certified engines and Jon ( the project manager, sorry I can't remember his last name), showed me a return loop that ties into the fuel line between the tank and the electric fuel pump. You run that for a few seconds and it cycles colder fuel foward of the firewall. That should solve the hot start issue. That adds complexity and on the fuel injected airplane I owned at one time, I would just open the oil filler door after landing and that seemed to work well to cool things down. During one quick fuel stop we landed, pulled up to the pumps, the FBO filled her up, we paid, and got right out of there. It started right up and it had been shut down for no more than 15 minutes. And that was in the middle of summer. OAT around 85 F. Sincerely, John Brunke ________________________________ Message 2 _____________________________________ Time: 09:01:09 AM PST US Subject: RE: RV7-List: Initial biuld decisions From: "Hinde, Frank George (Corvallis)" You could easily add an Airflow Performance "dump valve" to just about any FI system. This simply needs a return to either tank. It is only used to purge the hot fuel from firewall forward doing a hot start. It works, adds very little complexity and does not require any change to the standard selector valve. Frank -----Original Message----- From: owner-rv7-list-server@matronics.com [mailto:owner-rv7-list-server@matronics.com] On Behalf Of J. Brunke Sent: Monday, May 14, 2007 6:55 AM Subject: Re: RV7-List: Initial biuld decisions Dear Carl, In your well written response you wrote: > there is some complexity, higher fuel line pressures, need for a > return fuel line to a tank and more expensive fuel selector, more > difficult hot starts. In my search for engines that started at Sun and Fun, I specifically asked the fuel return question to most of the engine sales people. Aerosport and Mattituck both said a return line is not needed in their fuel injection systems. I can't remember the response of the other engine groups, but reducing complexity is probably better for sales. I always assumed one would be required also. That eliminates some of the complexity issue and relief for me since I had already sealed up my tanks. That also means a less expensive fuel selector, so that might bring the injection system somewhat closer in price to the carb system. As for the hot start issue that could be a problem. Lycoming is now selling non certified engines and Jon ( the project manager, sorry I can't remember his last name), showed me a return loop that ties into the fuel line between the tank and the electric fuel pump. You run that for a few seconds and it cycles colder fuel foward of the firewall. That should solve the hot start issue. That adds complexity and on the fuel injected airplane I owned at one time, I would just open the oil filler door after landing and that seemed to work well to cool things down. During one quick fuel stop we landed, pulled up to the pumps, the FBO filled her up, we paid, and got right out of there. It started right up and it had been shut down for no more than 15 minutes. And that was in the middle of summer. OAT around 85 F. Sincerely, John Brunke ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv7-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV7-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv7-list Browse Digests http://www.matronics.com/digest/rv7-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.