Thu Jan 13 2011

Mounting antennas

Got back to mounting my antennas today. I've decided to mount the ADS-B antenna right below the elevator servo, on the centerline of the fuselage. Because of the rib between the F-706 and F-707 bulkheads, I had to trim 1/2 inch off the side of this doubler.

Got the two screw holes match drilled, then used a unibit to open up the center hole for the BNC connector to 9/16 inch.


Looks good from the outside, too.

Having previously talked to Navworx, I learned the transponder antenna needs to be no less than 60 inches from the ADS-B antenna. This positioned it just forward of the F-710 bulkhead.

Transponder antenna installed.

Later in the evening, I started working on the fuel lines. Actually, before doing that I needed to cut a strip of rubber for the fuel filter to clamp tab. I had cut one of these pieces too short previously and Van's doesn't give you one iota of extra rubber strip, so I ordered some more a while ago.

Ready for the fuel pump and filter.

After clamping the pump and filter to the F-7115A mounting plate, I positioned them in the forward fuselage. The Red Cube (FT-60) fuel flow transducer needs to go in this area, too. It's sure going to be crowded.

I started my plumbing work on one of the interconnect lines between the filter and the pump. This is the first bend.

It was made with this cheap-o tubing bender.

The outside of the tubing got kind of flattened.

...and I ended up with a gouge on the outside of the tubing. I think this was caused by the tubing not being quite straight, so it didn't lead in to the groove correctly.

After checking AC 43.13-1B, I found that some flattening is OK as long as the flattest part isn't less than 75% of the original tubing OD. No problem there. Scratches can be burnished out as long as they don't exceed 10% of the wall thickness. I think that gouge would have been OK. But the minimum bend radius for 3/8 tubing is 15/16 inch. My bender is making bends that are 3/4 inch radius. Drat. Looks like I need a new bender.