The first image shows the recommended distribution of components for the electric version of the Cularis. (Click for higher resolution). In this configuration, the plane balances at the CGO with 3 weights (supplied in the kit) fixed under the tail plane. The component weight budget is
This gives a total of 670gm. The manufactures claim an all up weight of 1680gm with a wing loading of 30.5g/dm2.
In this image, I have added the Pentax A30 camera and a PicoPilot with PicoGPS. The camera is about 8mm wider than the center opening in the fuselage, so I will have cut back the sides for it to fit. I will also machine out a stepped hole in the base for the extended lens to sit in and see through. If I try to locate the camera further back, then I will have to machine out the two servo openings as well.
The addional weight is
However, I think the real problem is not the weight but the COG. A simplified calculation of the moments of the camera, the autopilot and the new position of the Tx about the COG, suggest that I will have to add about 70gm to the tail in order to bring the plane back into balance. So the total additional weight will be in the order of 283gm. This will increase the all up weight to 1963gm with a 16% increase in wing loading to 35.6g/dm2.
Although it may be standard practice, I am not really happy about have separate Fight and RX batteries. There are two things to charge and check before each flight and it just seems more elegant to have a single power source with a switch mode SportsBEC. With some searching, I found a DuraMax UltraPro 3s 3600mA Li-po with a flat form factor. The dimensions are 145mm x 50mm x 16.2mm. With a small amount of machining, this will fit in the space previously occupied by the Rx battery. The weight at 280gm
plus a Sports BEC is only 35gm more than the previous battery configuration. The real gain is in the balance, as the new heavier battery is behind the COG.
By moving the Rx and autopilot back as shown, the balance weight reduces to 25gm, so in all this solution is a little lighter than the previous one and I get more battery power