Monday, February 23, 2009
A tail tale
My goal for the winter on the project was to get an electrical system designed and to get everything in the tail of the airplane put together so I can rivet up the top skin as soon as the weather warmed and human flesh can stand holding a bucking bar for longer than 10 seconds.
Since I have relatively little electrical past the baggage area, I'm on track. A few weeks ago I laid out the strobe wire runs and on Sunday I finished up wiring the cables at the power supply end.
The Van's mounting plate for the power supply is handy, but when you really look at it, it makes a wiring run a little problematic, at least compared to the folks who stick the thing under the baggage area. I'm going to have to pick up some of the sticky nylon zip-tie mounts and stick a few on the belly to guide the strobe cables properly and keep them from flopping around.
In the picture below, you can also see that I soldered wires to the drain wire, and ground them on the j-stringer that's part of the bottom skin. I could have grounded them to the mounting plate (and I probably will do that for the power ground, but I'm not convinced there's great metal-to-metal contact there. Part of it is I'm not well schooled in how much metal-to-metal contact there needs to be there.)
The other thing I'm doing is running the antenna cable to the top of the plane. I'm going to have the antenna sticking out in the breeze where I'm sure it will work should I need to activate the emergency locator transmitter from a panel switch. Once I ditch, the plane will probably flip, making the location of questionable value, of course.
As you can see, I'm running the antenna forward along the main rib, forward of the elevator bellcrank assembly (it doesn't interfere), and then up the inside of the bulkhead back toward the exit point in the skin.
I have to order a few more DG-3 Adel clamps for this.
I have some concern about the remote magnetometer for the Dynon that has to be installed behind the 707 bulkhead, I believe. There's no current running in the antenna, of course, but I don't know if the mere presence of the wire will screw things up.
The only other wire that needs to run from the tail area, is the panel-mounted switch wire for the ELT. Once I add that -- maybe next week -- and get everything secured, I'll get the skin clecoed and buttoned up. Assuming I can find some riveting help, of course.