Engine Mount & Update

Update on my SSDR, mainly on the engine installation. Based on the feedback I received on the mounting, combined with my dissatisfaction with available space, I tracked alternative mounts and did a rework.

I got some second hand but serviceable Lycoming and continental mounts. As I could fit the Lycomings I opted for them as they are very substantial.

Moving the cross mounts to an underslung position gave much more clearance, I made up larger cross mounts with bigger clearance holes on the side bolts, so they can be insulated as well.

I was planning to start routing the rudder pedals, and noticed in my somewhat hasty decision to put the arms on the hingepoint, the stabilator obstructs them entirely.

I needed to start on the exhaust, I cut up the monstrous Rotax head unit, made much lighter mounting plates, blasted what was left, cut off the connection point, and welded back together with out the excessive flanging. I used an exhaust calculator to produce dimensions to suit the engine specs, and printed off templates, making up a rough and ready expansion chamber exhaust. I will borrow an original Rotax to give a performance baseline and see how it runs. Below: Mig welded experimental exhaust, still a lot to add its short about 4 sections.

At the same time I noticed some workshop rash had put a large scraped dent in the rudder, so I drilled the skin off, annealed and planished the main dent out, stress revealed as much as possible with a quick bead blast and re anneal, then put a doubler on, which gave a reasonable finish on the repair. I moved the arm down and included a reinforcement doubler to move the load into the skins in shear rather than try torque through the thin spar.

Pictures show the result and fin in position.