lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> In a message dated 7/31/2001 9:18:23 PM Pacific Daylight Time, lancair.list@olsusa.com writes: << Do you have anything else connected to the gear up circuit ? >> This brings to mind Tim Ong's excellent landing lights. These babies are clamped to the landing gear leg and should not be on while the gear is in the wells. Consequently, Tim has designed a circuit with relays and whatnot intended to keep power off the lights while the gear microswitches are open. I have not studied Tim's circuit, nor anyone else's circuits which depend on the state of the landing gear (a two-speed elevator trim circuit comes to mind as it was discussed in this forum years ago). I'm not saying that Tim's or the other circuits can gererate a sneak circuit of the type Sven alludes to. However, it's more "stuff" hanging off the gear circuit, which I wanted to avoid. I replaced my SPDT gear down switch with a DPDT switch (from Pacific Coast Avionics, I think). I use one pole for the gear up-down circuit in the usual manner. I use the other pole to interrupt power to the landing lights. This replaces the relay in Tim's circuit. They are two completely isolated circuits, except for the fact that they share different halves of the same switch. (Oh, yes. There's a separate "landing light on-off" switch in series with the landing gear switch -- the landing gear switch simply ensures that the lights are not on while the gear switch is in the UP position) If I were so inclined, maybe I could leave the landing lights switched on and wait for the glowing wings to indicate that the gear switch was DOWN but the gear was still in the wells....or put a plexiglass plug in the wing skin (like the BD-5 fuel gauges) and if the plug is glowing, the gear's up....but I won't. - Rob Wolf LML website: http://www.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com.