Huge Progress on CAC Boomerang restorations by Greg Batts

It has been some time since a report has been done on work being carried out by Combat Aircraft Constructions (CAC) at their workshop near Archerfield Brisbane, on several CA12 Boomerang fighters being A46-77, A46-55 and A46-54.

CA12 Boomerang A46-77

This Boomerang has taken a milestone step with the mating of the fuselage to the wing centre section on Christmas Eve 2022. The step occurred with only minor and solvable hitches.

Previously the new undercarriage outrigger mounts had been installed prior to the wing tanks being fitted on both sides and the tank doors attached. Two overhauled undercarriage retract rams have been installed to the outrigger mounts and hydraulic piping connections to the centre section made and installed. The next step was to complete the over wing fillets, followed by the trailing edge fillets that lead back onto the lower monocoque pan. These fillets are difficult to remanufacture due to their continuous changes in shape as they proceed back over the wing to the fuselage rear.

Having completed this, the fuselage was then painted in its two-colour Green/Brown scheme with Sky Blue under surface. All of the fuselage stencils have now been applied. With this done the whole tail assembly has now been removed along with the fillets and Wooden Fuselage Covering to allow the internal fit-out to progress. Most internals components are ready to instal, with this proceeding over the next couple of months.

While the wooden fuselage covering is off it will have its squadron markings (MH-S) applied to both sides in Medium Sea Grey colour.

It is planned to have the undercarriage overhauled and installed prior to Christmas. New rims, tyres and tubes are held for fitting. Brakes will be next. Once standing much more fitting out will be completed focusing on electrics, hydraulics and cockpit fit-out. Main fuselage fuel tank is currently under build and its plumbing will be attached once in the airframe. With cables in, it will be tail assembly back on followed by return of the Wooden Fuselage Covering. 2024 should be exiting as we head out to the noisy end of the aircraft.

CA12 Boomerang A46-55

This Boomerang has now advanced in its restoration project. The cockpit tube frame has been X-rayed and found to be totally sound, so it was blasted, treated and primed, and then its cockpit 4 colour scheme applied. It is now in the process of having all of its internals overhauled and being refitted. As this occurs the lower monocoque pan has been placed in the jig and stripped completely. It was found to be in need of repair and this has now been completed. New tail wheel pivot castings have been CNC’ed, as the original magnesium ones were unacceptable. The skin had previously be made new, so this was paint stripped for inspection and reprimed ready to be rivetted back on over the next month. Work will then centre on the rear fuselage frame, with X-raying and any repairs necessary being done. Blasting, treating, priming and painting to follow.

Once all this is completed the three components will be joined back up and realigned ready for more extensive fit-out. Readers will remember that the airframe was full of all its components when obtained by Greg Batts making the task of fit-out a much easier one. The tail assembly will be a conversion from Wirraway to Boomerang. The Vertical fin is currently under modification to Boomerang configuration. This should be finished within the next month. Next will be Horizontal Stabilisers. Elevators and rudder are held to complete the tail assembly.

The Wooden Fuselage Covering is made and currently having its metal work attached. This should be completed by month end. So much advancement and the following months and year should see major advances in this project.

CA12 Boomerang A46-54

This Boomerang has made leaps and bounds toward flight. Moved from the workshop to Toowoomba Airport’s Aerotec hangar, the aircraft has had its Propellor fitted for the first time in 60+ years along with refitting of the outer wings. Next to follow was the ailerons, with these presently undergoing positions setting and cable tensioning.

The enormous task of finalising the paperwork got under way, as inspections were being carried out. The aircraft underwent a weight and balance test requiring the manufacture of a ballast box and a mounting structure to be fitted into the rear of the fuselage above the tail Jacking casting.

Problems were expected to occur, and this arose out of a faulty altimeter which continued to fail test. Four additional altimeters were obtained across Australia with all also failing. Finally, this was solved and a working altimeter refitted, but the move forward was again plagued by leaking screws of both oil coolers, resulting the removal of most of the underside panel work of the nose to allow the complete removal of the cooler apparatus to a bench, where new crush washers and sealant were installed, stopping the leakage. Then the task of reinstalling the whole apparatus back into the aircraft and reconnection of systems and reattaching all the panel work.

Any minor matters have been handled along the way, and the aircraft is about to start engine runs to prove systems. All going well we will most probably see flight test in the near future.

Interestingly, along the way of doing the paperwork, prior history of the aircraft in service needed to be established. An extensive search commenced for data that has resulted in record from many pilot log books of flights in the aircraft. Of particular note were two entries noted below.

As first flight since 1945 approaches, Warbirds Online looks forward to seeing this Boomerang at Airshows for the pleasure of all to see in the air again.

© John Parker 2023