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.
main undercarriage mounted on 40mm fibrelam spacers (to gain more prop clearance)
Main suspension with stronger ‘carry-thru’ (not butt welded) axles and upgraded pultrusion rods (made from Plexinate P-100 polyurethane resin with 73% glass content)
upgraded nose-leg with machined spacers, adjustable retaining strop and welded webs (supporting the trailing arm pivot)
fuel transfer valve (wing tank to main tank) – 3/8″ bore shifts 28 litres in 10 mins
The tail boom has been fitted into the centre section and the nose cone has been repaired and trimmed to fit around the footwell fairing. Now its time for painting the fuselage.
Recently, I’ve done hours of fibre-glassing, filling and sanding on the fuselage rear footwell and wing centre section to get them reinforced and smooth for painting. Side windows have been cut out (between the front and rear canopies) to widen the pilot’s field of view. An improved fuel transfer system has been fitted, so by twisting a lever the pilot can quickly transfer fuel from the wing tank down to the main tank. The wiring loom, new brake cables, new elevator trim cable and new elevator Teleflex cable have now been threaded into place, and the kevlar sides have now been glued onto the fuselage.
RAANZ has approved some mods, so Bruce has constructed an up-rated 450kg main undercarriage and added a deeper footwell for passenger comfort (with a streamlined fibreglass fairing). Lots of fun has been had machining undercarriage inserts, axle spacers, threaded inserts (for fitting rod ends) and window latch parts.
Shadow B-D (ZK-KLH) stripped down before restoration
Bruce’s personal project is re-building and modifying ZK-KLH, a Shadow B-D microlight. Murray Hagen originally built this aircraft in 1989, alongside its sister CFM kit plane ZK-TTE. After seven years of flying, dogged by many engine failures, one day the Rotax 532 finally gave up. The result was a ‘less-than-happy’ landing breaking the main landing gear and damaging a wingtip.
During storage one of the big Fiordland earthquakes damaged the wing leading edge, a prop blade was broken and pesky starlings had picked huge amounts of foam out of the centre section ribs. Fortunately Murray was able to supply spare foam, plywood, new wingtips, new main landing gear, a replacement prop (custom built by Brent Thompson) and an unused Rotax 582 engine.
The wing’s 1.2m plywood leading edge has now been repaired. Much of the restoration work on the fuselage and wings has now been completed. The aluminium joining tubes of the tail feathers have been crack-tested – some replacements and reinforcing were neccessary. UHMWPE bushes have been fitted inside the tail boom to stop wear on the tailplane mounting tubes. The tail surfaces have been re-covered with polyester fabric.