Well if you've read this thread from the start, you'll know the a/c is already flying, but back to the build story..
STage 2 - the engine.
Having spent the last couple of months covered from head to foot alternately in glue/paint/dust, I was really looking forward to a bit of what I saw as ‘proper’ building – getting covered head to foot in oil. Accordingly, I was very excited when we took delivery of a shiny new Rotax 912ULS on the 6th January.
I had never seen an aero engine out of an airframe before, and was struck at how small and light the engine was. I thought it was beautiful and even Mrs M9, whose artistic temperament is generally indifferent to things mechanical, agreed it was very pretty.
The engine is supplied by Rotax ready to bolt straight on to most installations. However the design of the Pioneer engine frame required adjustments to be made to one of the water pump inlets, which required turning through 5deg.
The aluminium water pump inlet bend is heat shrunk onto the pump body, and accordingly requires heating before it can be turned. I first attempted it using a paint stripping hot air gun, but despite applying the most force I dared on a screwdriver inserted in the inlet, it refused to budge.
I chickened out at that point, and hot –footed it round to Frank’s water pump in hand. His hot air gun was obviously made of far sterner stuff than mine, and the inlet turned easily once hot enough.
The engine is mounted into the frame on four rubber vibration dampers. It is an extremely tight fit, the vibration dampers are under considerable compression. It took three of us to fit, a friend and I deftly manoeuvring the engine, with Mrs M9 delicately sliding the mounting bolts into position. Well that’s how the manual said it should be done. Reality was Mate & I alternately heaving and shoving engine, and Mrs M9 whacking bolts with a 4lb rubber mallet. After numerous bruises and broken fingernails, hefty contributions to the swear box, and about three hours, the bolts were all in place and torqued up.
The rest of the firewall-forward installation was fairly straightforward. The oil cooler and air filter boxes, battery, starter solenoid, fuse box, fuel booster pump, and gascolator were all secured to the firewall with rivnuts. The radiator was mounted on the frame under the engine, and the various lube, coolant and fuel piping systems were installed. The engine wiring loom was supplied mostly complete by Alpi, and only required the appropriate connectors to be crimped onto the ends for connection. Bowden cables were then installed through the firewall for throttle, choke, carb heat, and cabin heating. The stainless steel exhaust installation required lagging with heat-proof tape prior to installation – more work for the wire-locking pliers.
On to the cowlings. The kit comes with two halves of the carbon fibre moulded cowling. The mouldings require trimming to size, connectors fitting, and a NACA vent installed on the lower half.
First job was the trimming. To correctly position the cowling, Frank had supplied a template which bolts onto the prop driveshaft. The cowling halves are clamped and taped to this, then marked off against the fuselage. The cutting is easy enough with a hacksaw or disc cutter, and when sanded gives a nice smooth edge.
The hole for the NACA fresh air vent was cut with a Dremel – a tool I found to be absolutely indispensable during the build. Installing the thirty-odd cowling connectors proved to be time consuming, but was simple enough.
The prop and spinner went on next. Once they were on, I was itching to do a trial run of the engine, and being a Scouser, was of course well educated in the art of hot-wiring. However discipline prevailed, and I resolved to wait until the panel and wiring loom were properly completed.
Stage two had taken a little over two hundred man-hours. (Total to that point 560). Stage three was to be panel and wiring, and then another part I had been somewhat wary of – windscreen and canopy.
To be continued in part III…