Day 230

Today we made a box to mount the long range fuel transfer pumps. We had a few issues to overcome regarding these pumps.

First issue was that Sling has the system designed for one pump to pull the fuel from the tanks to fill the main tanks simultaneously. However the wiring harness we received from Midwest Panels is designed for the use of two pumps, one for each tank that can be drawn from independently.

Second issue we ran into, the build manual does not go into any detail as to how or where anything is supposed to be mounted, regarding the long range system. It just gives a diagram showing how the system is meant to work… Which we have to modify anyways because we’re going to be utilizing a two pump system anyways. That being said, we had difficulty figuring out where we wanted to mount the in-line pumps. We tried to see if they could mount underneath the front seats along the main spar (which is where the fuel lines run from the wings to the center console) but there just wasn’t enough room for them to fit.

We then moved on to trying to somehow make them fit along the center channel, underneath the console. This was difficult to figure out because there is not much space here. Everything is running through this arena; The main wiring to the fuselage, all antenna cables, fuel lines, brake lines, throttle cable, rudder cables, and not to mention the brake/ throttle quadrant, Flap actuator and Fuel selector. (Yeah, everything) We have no choice though, but to try and make them work here because there is absolutely nowhere else they can go.

So we came up with a mounting box idea that would house the two pumps on top of one another, trying to keep everything as compact, yet versatile as possible. We designed it to sit just above the wiring and cable harnesses, allow the rudder cables to pass through without interference and to allow enough space for all the rest of the lines to pass over. We also designed the apparatus to be removable so that if there needed to be maintenance done to the pumps, or access to the wires and cables below this could be accomplished.

We used aluminum angled brackets, spacers, rivets, rivet nuts and bolts to hold everything together. The mount is held up at a hight that allows the rudder cables to pass through and cut a section of the angle brackets out so that they would not interfere on the sides. And the top was mounted at a hight so as to not interfere with anything either. Pretty confident it will be a strong mount and will work for the system.

The next project will be to get all of the fuel lines and fittings to fit and work in the small space.