build, restore, upgrade + repair microlight aircraft
late 80’s CFM ‘Shadow’ microlight aircraft
My wife and I, assisted by Malcolm Swanson, unloaded the Shadow microlight at the Fiordland Aero Club’s hangar at Manapouri Airport.
Over the next few days, I worked on installing the gearbox, radiators, carbs, etc. My wife helped by gluing the blue closed-cell foam foam padding onto the seat bases/backrests, securing the electrical wiring inside the cockpit and applying the vinyl labels to the instrument panel.
Nearly 8 years apart, both these photos are taken at Murray Hagen’s home near Manapouri.
Murray and his mate, Danie Gouws, built two Shadow B-D kits in his large shearing shed. Murray’s Shadow microlight aircraft first flew in 1989 as ZK-KLH. while Danie’s plane was registered as ZK-TTE (after Tuatapere, the nearest town)
So here it is, the same Shadow, but considerably restored and improved. Almost everything has been dismantled and re-assembled, with repairs as necessary.
The ‘points’ ignition Rotax 532 has been replaced by a new Rotax 582 with dual CDI system. Larger radiators for better cooling. Larger footwell for rear passenger. Landing gear uprated from 395kg to 450kg. Extra side windows.
Immediately after our Christmas and New Year holiday with our family at Lake Manapouri, I headed back home to Invercargill.
The aim was to prepare the Shadow for transport 150km to the Manapouri Airport for final assembly, engine start and test flying.
My son patiently fitted the various sensors to the engine and connected a myriad of coloured wires up to the voltage regulator and/or the wiring loom.
I concentrated on miscellaneous tasks, such as fitting seat belts, setting up the pull-start system, mounting the oil injection tank and fabricating a horizontal fuel pump mount. I also checked the operation of coolant temp sender, thermostat and gauge, and the fuel sender and its gauge.
Finally the Shadow was loaded onto our yacht trailer for the trip back inland to Manapouri.
The original fuel tank, made from panels of aluminium honeycomb core sandwiched between phenolic skins, was looking a bit sad. It deserved some attention.
The tank’s interior was in good condition, except that the fuel outlet mesh screen (made from a “tea leaf strainer”) had come adrift. However, the exterior seams had some worn areas.
After careful sanding, I filled any voids with epoxy filler, then glassed each seam. After final finishing, the tank looked much more presentable.
I created a large finger strainer from 0.3mm brass mesh and soldered it into the outlet fitting. Hopefully this will prevent larger bits of rubbish getting into the fuel line and clogging the fine filter.
It was satisfying to get the new Rotax 582 out of its box and sitting on the Shadow’s engine frame at last.
But it was only there temporarily, as I took it off and put it on repeatedly while I did a series of jobs before it can be installed properly.
A small change in the 582 crankcase moulding necessitated grinding out two clearance scallops in the rear engine plate.
Next, I custom-made some exhaust mounts, taking care to have muffler tilted to the same angle as the rear bulkhead. The cylinder head mount neatly skirts around the spark plugs and features an access hole for the temperature sender. Stainless bands hold the muffler to its webbed mounting plate. Two LORD rubber mounts will help absorb vibration.
Lastly, I wanted to align the pull-start cover and re-route the starter cord, so it didn’t rub on the rear hanger tubes. I added a ‘turning’ block to achieve this.
Now it’s off to Leitch Motorsport, so Barry can weld on the 12 loops which take the 6 springs holding the manifold and elbow ball-joints together.
Over the past few weeks, I’ve been able to return to re-building my 1989 CFM Shadow ZK-KLH.
The next task was to make new canopy windows. Unfortunately, I couldn’t source tinted 1.5mm polycarbonate in New Zealand, so had to settle for clear windows. The old windows made good patterns, not only giving me the correct outline shape, but also allowing me to pre-drill the rivet holes.
Each rear window had a single central latch which resulted in bent lower tubes, so I opted to replace these with twin latches to securely hold the window closed. I machined new latch axles from solid alloy and filed two ‘flats’ to positively locate each inner lever (i.e. it no longer relies on friction to stop the inner lever from rotating out of alignment). Overall, these new latches are stronger and more secure, but only a few grams heavier.
The rear windows also have a full-length lower tube (with a matching horizontal cut-out in the rear bulkhead), so that the lower rear corner of the window is not floppy. Where each latch is drilled, there is an alloy sleeve to strengthen the tube and reduce the tendency for the axle hole to wear.
PS: You can see the small side windows that were added to the canopy shroud. They will give the rear passenger a better forward view.
Last weekend, the Shadow microlight project took a big step forward towards completion. That occurred when the fibreglass nose cone was glued onto the honeycomb fuselage tub.
Then began the long job of mixing lightweight fairing powder with 2-pot epoxy and carefully filling every hole, crevice and hollow. Once the epoxy has set, I spray on a faint guide coat of colour paint, followed by even more hours of sanding down the filler. The coloured guide coat shows up any imperfections in the surface, so the process needs to be repeated until you’re happy with the smoothness. Since the aircraft is old, I stopped well short of perfection – it will look OK from a distance..
Today I masked up the fuselage, then sprayed an adhesion coat onto the fibreglass nosecone, kevlar side panels and thin plywood canopy shroud. Hopefully that will help the water-based paint to stick well.
A few weeks ago, the new Rotax 582 ‘Blue-top’ engine arrived. It is fitted with oil injection and a by-pass cooling system. This system is an improvement over the 582 ‘Silver-top’ model because it keeps the coolant circulating within the engine block, while the engine is warming up. When the thermostat does open, it diverts hot water to the radiators and closes off the by-pass.
Wiring up electrical systems gives me the ‘heebie jeebies’ – I’m never very sure whether the sneaky little electrons will go where I want them to go or if the wires will suffer a melt-down (thereby letting ‘the smoke get out’ of them).
I’d already spent hours on the computer working on wiring diagrams – colour-coded wires, switch banks, earth buses, filtered avionic supply, etc. That’s all very nice, but eventually someone has to cut
actual wires and crimp on actual connectors. I’ve sat at the nose of the Shadow for quite a few hours tentatively cutting, labelling and crimping. After the first session, I’d done five wires, and only made two mistakes! One was too short. Another had the wrong label.
The final result is OK I think, but needs a better way to support the bundle of wires.
Now completed the covering of the wing’s centre section.
With the help of my brother-in-law and his wife, we flipped the fuselage/wing centre upside down (and carried it back into the workshop) so I could work on the underside of the wing stub. It was very easy to cover it with lightweight Poly-Fiber fabric and then gently heat shrink it smooth. I was pretty pleased with the zipped access panels that I’d sewn in before gluing the fabric on.
The brushed-on sealing coat was Wattyl “Solagard Gloss” water-based roof paint (with Floetrol conditioner) thinned with BarsBugs. This flows across and through the weave, gripping the polyester fibres much better than conventional fabric sealers. Next were several sprayed coats of Solagard Gloss/Floetrol thinned with water.
My brother and I carried the inverted fuselage/wing centre out of the workshop and flipped it back onto its wheels. Then, I could cover the top surface of the wing’s centre section. It took some ingenuity to sew and glue fabric shelves along each side of the tail boom, so that I could eliminate the foam shapes that normally surround the boom as it exits the centre section.
I also fitted the underwing luggage locker. It’s a hinged divinycell tub, which can hold a sleeping bag and small tent. In the open position it give easy access for connecting the port-side aileron pushrod. When its closed the luggage is prevented from fouling the pushrod. The starboard-side aileron pushrod is accessed thru the zips mentioned above. There is a 28 litre fuel tank above and aft of the pushrod, which more than doubles the Shadow’s range.
Today I wheeled the Shadow out of the workshop and took some photos to show progress on my re-build. It’s looking like an aircraft again.
It’s been a satisfying couple of days. Yesterday I’d attached the wing centre section and tail boom to the fuselage. Obviously the undercarriage had been mounted underneath to hold it off the ground.
Over the past week I’ve been able to tick off a whole bunch of tasks from my list, including assembling the polyurethane flexi-rod tail skid, mounting the fuel transfer valve with its on/off control rod, crimping the limit wires for the rudder pedals, nose-leg suspension and flap lever. In addition, I have sprayed the instrument panel black, made the polycarbonate side windows and finished sanding the leading edge of the wing centre section.
Very pleasing to see this amount of progress in a week.
