Thank a lot to all who expressed their opinions, they are very helpful for my overall approach in using vacuum-driven instruments ! I do not intend to fly IFR but would like to enjoy the turbulence-free winter flying in Canada, which is subject to severe icing and quickly changing weather. What I know regarding the dry vacuum pumps, is that they break every 500hrs or so in my flying club C-152/C-172's, the extreme temperatures are probably contributing a lot to shorten their operating life. I will continue to explore the use of "no energy loss" vacuum but will also consider a belt-driven wet vacuum pump from automotive engine. Many of you are probably considering exhaust gases augmented cooling, venturi-assisted cooling air output ports, etc. - there is enough "energy" for a decent suction, I believe. I have been designing for many years touchscreen-enabled devices, I may probably design my own low-cost electronic AI. EFIS-simulated artificial horizon is for sure a good solution for getting out from IMC... but I have a preference for independant from electrical power solutions. By -20?C, the battery is not the best power source...
Stefan Ottawa, ON, Canada s_sbal "at" hotmail.com
