Inadvertent backup systems

N941WR · #1 07-31-2006, 09:58 AM

Yesterday while showing my project to a fellow RV builder and now flier it occurred to me how lucky we homebuilders are.

As I?m building my simple Day / Night VFR airplane I have managed to include a LOT of redundant features. The funny part is that I didn?t design the electrical system with a lot of redundancy in mind because I intend to keep this thing VFR only.

As I talked through the systems it just hit me like a ton of bricks.

The duel Pmags I?m installing give me triple redundancy by being self powered and being able to run off the ships electrical system.

The Garmin 396 has an internal battery so it has backup power.

The Dynon D100 EFIS has a 2.5 hour backup battery so, again, it has backup power.

If I bring my hand held radio with me then I have just about everything I need.

More actually, because I don?t need the radio to get back on the ground.

What have the others of you done that falls into this category?

dan · #2 07-31-2006, 10:20 AM

E-bus alternate feed...if the master/battery contactor fails, the essentials can still be powered.

XM Roady2 and ipod...gotta have redundant music sources!

vlittle · #3 07-31-2006, 10:33 AM

Bill, my 9A is almost the same setup as yours, except my engine monitor *also* runs off of backup power.

This was a deliberate choice by me, and when I had a master switch failure at 8500' over the mountains, it served me well.

I had primary flight instruments, primary nav, primary engine instruments and secondary nav/comm all running of of internal battery backup.

Since I have manual trim, I was in fine shape to finish the flight. I only wish I had manual flaps.

As a note, a local builder has put manual flaps into his -9. Since the flaps only deploy to 32 degrees, he came up with an arrangement for new flap linkage that should work well.

Good show,
Vern Little

Davepar · #4 07-31-2006, 10:47 AM

For a while I was thinking about a back-up alternator, but as you mention there's already triple back-up with dual P-mags:
1. alternator fails, I switch to battery
2. battery fails, P-mags automatically switch to internal generator
3. one P-mag fails, the other will keep running

N941WR · #5 07-31-2006, 10:58 AM

Quote:

Originally Posted by vlittle

As a note, a local builder has put manual flaps into his -9. Since the flaps only deploy to 32 degrees, he came up with an arrangement for new flap linkage that should work well.

Not to let the thread drift but that is something I would like to see a picture of.