Looks very nice !
I have made the suggested cross brace from plywood. It also works as a block to hold the upper, header tank from sliding back (shown is a mock tank, not the real one). It will be 3 1/2 by 7 inches). The header tank is centered over the CG. My total fuel capacity will be 3.5 liters plus another 250cc in the air trap. The P-130 uses 500cc/min. I should get a good 7 min. of flight with plenty left over for a few go-arounds if needed.
You can also see the servos that actuate the main gear doors. These servos with hardware and arm weigh in at 17gm each. Again, I am going all electric. The aluminum cylinders with a foot of each air line also weigh in at 17gm each. They would have to be twice as long or more. Then there is the air line actuator, the servo to move it, the fill portal and pressure gauge as well as air storage tank. The weight saving in this circuit alone is significant.
