I acknowledge that I haven't been as active on the build thread as I'd like, but I have a family and friends who were getting a bit jealous of the time I was devoting to Byron's plane and demanded their fair share! I haven't been totally idle, however, and I have now completed the cone.
From the CofG calculations, and a decision to fit the extra two servos in the tail, I knew that I needed to fit all three batteries as far forward as possible. I therefore removed the battery box built to hold the Relion 2600 Ah ignition battery, and constructed a new battery box to hold the two Relion 5200 Ah flight batteries as well. As before, the battery box was constructed of 3mm birch ply and lined with 5mm foam rubber around and between the batteries to isolate them as much as possible from vibration. The box was screwed onto the firewall with 6 x 18mm brass wood screws and the batteries were retained with a velcro strap.
I moved the ignition 20mm higher to releive some strain on the high tension lead to the left cylinder which also required me to move the hole for the ignition wiring and reinstalled the grommet to prevent chafing. I removed the Smart-fly engine cutoff and reinstalled it across the top rear of the cone to keep the 'ignition stuff' on the right and separate from the 'radio stuff' on the left. This change also provided a neater wiring solution all round.
Byron wanted all of the electrical connections between the cone and the fuselage to be accessable on the 'outside' of the cone so I drilled two 25mm holes on each side and fitted them with grommets. The last hole was drilled at the front top of the cone and fitted with a grommet for the hall sender cable.
I was bit worried that the 3mm tap washers I had used to damp some of the engine vibration might crack under repeated use so I made up some engine vibration dampers from 6mm heavy duty 'laminated' rubber which were used to space the engine mounting plate from the firewall. I used large diameter washers and spring washers, held in place with a generous application of Locktite, to secure the engine onto the cone.
I needed to extend a few leads and shorten others to make sure all the connections fitted on the outside of the cone between the two wiring holes. I fitted three Ernst battery charging plugs in the fuselage on each side of the Emcotec and made up the extension leads for the 2 x flight batteries and the 3 x battery charging leads. Making the extensions for the battery charging leads was interesting because it was the first time I had made servo plugs using the connectors and special crimping tool (which after much searching I eventually found at Taits Hobbies in Geelong).
At this point, I spiral wrapped all of the cables and worked out the positions for the cable tie anchors which were epoxied in place in the cone and forward fuselage. When the epoxy was dry, I used 2mm cable ties to hold all the cables in their pre-determined positions, being careful to ensure that the battery cables were not 'anchored' in a way that would prevent the easy removal of the batteries for charging or maintenance.
As soon as I've finished tidying up the cables in the fuselage and fitted the fuel tank plumbing, I'll attach the cone to the fuselage connect up the cannisters and Locktite all the attachment bolts
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