lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> << Questions??? ERic-- >> The wealth of information provided was impressive. I understand how each cylinder has its own control circuitry and how a failure of one cylinder's control circuitry is taken up by the controller of the opposing cylinder. These paired cylinder controllers are called ECU's and it takes three of them to run the 550. Each of the three appears to be tied to just two cylinders. I have just one yes-or-no question: On the IOF-550 (not the four cylinder), if we lose or unplug one whole ECU do all six cylinders keep running? It appears that if the two cylinder controls in each ECU are electrically separate and fed from separate voltage sources, then the "6 computer / 3 ECU" system does have individual computer redundancy, but not redundancy in the event of one ECU box or it's cable going down as a unit. It also seems that the engine cannot run on one computer, but takes at least three evenly distributed between the cylinders (two for the 240). Obviously, the terms "ECU" and "computer" are not synonymous in this case and this is confusing. The reliability calculation becomes more complicated, but is still less than it would be if one computer could run all 6 cylinders. Again, this is not everyone's definition of redundancy. I'm asking what that is, and that admittedly diverse answer can only come from the customer base. TCM, Lycoming, and all other engine control vendors could consider the answers on this list to be an uncontrolled market survey. I know I'm curious. Eric Ahlstrom Star Aerospace LLC >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>