On Sunday, July 22, 2018 at 6:26:09 PM UTC-7, 2G wrote:
On Sunday, July 22, 2018 at 4:22:42 PM UTC-7, OHM Ω http://aviation.derosaweb.net wrote:
On Tuesday, July 17, 2018 at 9:36:26 PM UTC-5, Roy B. wrote:
Circuit breakers (not fuses)
ROY

I don't have a comment on which instruments to purchase. I only want to agree with Roy on circuit breakers over fuses. Also I feel that you should not use small value breakers (or fuses) less than 4A or you will pay a price in lost volts.

I prefer 5A+ combo breaker/switches (i.e. Tyco W31) over plain breakers.. Tyco's are bulky as compared to Klixon but the Tyco eliminates a separate switch and a additional failure point. I don't agree with using a plain breaker as a switch.

One other thing I like separate on/off switches for those avionics that don't have their own internal power off capability (I have two such devices - ClearNav and FLARM Core) to be able to reset a device or if you need to save dwindling power at the end of a long flight.

Best of luck.

John OHM Ω

John,

My problem is that I have identified 16 breakers and fuses. Some have to be fuses per Schleicher (about 4), so that leaves 12 breakers. The Tyco is over twice the area of the Klixon, by about 0.5 sq in. That means I have to come up with another 6 sq in of panel area, or 1 1/2 instruments. That just ain't happening.

Tom

Klixon breakers are rated for 5000 operations at full load and 30V. A decent toggle switch is rated for a lot more, but how many times are you going to switch it? That's 7 years at twice a day. A separate switch is nice, but adds wiring, takes space, and reduces reliability.

Out of curiosity, which circuits does Schleicher insist are fuses, and was there any rational to go along with it? The specs of glass fuses and good thermal breakers are functionally identical. From experience I know that Kixon breakers are more reliable than the glass fuse holders AS uses.

One more thing to point out is the micro rotary switches that AS uses for power switching are not really rated for typical currents. The ones supplied in mine (similar to NKK MRY106) were a 2A AC, 1A DC switch. I've seen lots of these in gliders. I replaced them with NKK MRT23 switches, rated for 3A DC, and paralleled the two poles for 6A.

I'd ask for a LED indicator pilot light on a couple of circuits: the Pump 2 and the Refuel Auto. These are easy to leave on and you don't want to.