CAC Boomerang Restorations July 2019

It’s some time since we reported on the progress that Greg Batts of Combat Aircraft Constructions at Archerfield, Brisbane is making with the restoration of a number of CAC Boomerang aircraft to airworthy condition and in the interim much has happened.

On the day of our visit 4 CAC Boomerangs were on the workshop floor undergoing restoration. CA-12 Boomerang A46-54 (Greg’s own project) is inching ever closer to its first flight with the host of seemingly endless small tasks coming to a conclusion. The hope is to fly this aircraft this year however the inevitable delays in details may get in the way of this schedule.

Recent activity on A46-54 has seen the propeller spinner back plate that attached to the 3E50 Counter Weight propeller hub redesigned and manufactured from scratch as it does not fit to the replacement 23E50 Hydromatic propeller hub being used. It was necessary to design and manufacture a new Back Plate for that hub, so that the original Boomerang Spinner could be retained. The propeller itself has been sent to a local Queensland specialist for assembly and testing prior to being fitted to the aircraft.

The Carburettor for the Pratt & Whitney R-1830 Twin Wasp radial engine, 1,200 hp (895 kW) was sent to the USA for rebuild by a specialist and has just arrived back after a prolonged process and is reported to now be fitted to the aircraft. The engine is a genuine R1830-90 used for the Boomerang by CAC and was rebuilt for the project some time ago and is already in place in the aircraft. Final system connections to it should complete within a month.

Whilst the vast bulk of the aircraft systems, instruments and components are completed and fitted to the airframe, several instruments are being refurbished and fitted and the last of new control cables are also being fitted. New flap rods are now being installed and connected to flaps. Once all of this is complete a full aircraft inspection will be done and then the fabric covered wooden shell of the fuselage will be refitted for the last time and painting of some areas of the aircraft undertaken. All of this activity should see A46-54 ready for first flight trials before Christmas, however as mentioned Warbirds can be cantankerous beasts so we have our fingers crossed.

A46-54 is located in Greg’s workshop which is not situated on the airfield so when the aircraft is completed in the near future it will have its wing outer panels removed and the entire aircraft will be transported to Caboolture airfield near Brisbane Queensland for reassembly and trial flights. Progress on other aircraft in the workshop has also been excellent.

CA-12 Boomerang A46-55 had at the time of our last visit only just been taken out of storage prior to restoration being commenced and since then progress is amazing. The fuselage which was remarkably complete internally has been stripped out of all components for a new bespoke wooden shell to be constructed.

Regular readers will be aware that the Boomerang wooden shell is unique to each aircraft given the nature of CAC Boomerang construction and no two shells are identical. The shell for A46-55 is the first one Greg has used which is constructed from Australian sourced Hoop Pine as the previous shells were all constructed utilizing North American sourced timbers which have proven to be almost impossible to obtain recently. The Australian material has proven to be an excellent replacement and in some ways even better.  The majority of the metal components have now been made and fixed to the wooden shell.

A46-55 will now have the shell removed again to allow for the refurbishment of the internal frame and will then be fitted out with all of the hydraulic, electrical and fuel systems as they are refurbished as well as the seat, cockpit fittings, controls and instruments. The canopy is in the process of being rebuilt.

A new North American Harvard Mk IV center section is in the process of being converted to CAC Boomerang configuration. Readers of previous articles will be aware that this Harvard item is similar to the Boomerang component and can be converted to be a near exact match, however it is a time consuming and complex task. Once this wing center section is complete it will be mated to the refurbished fuselage.

New build outer wings will be constructed while most of the tail assembly is already in storage awaiting rebuild. The firewall and metal forward fuselage panels have also been trial fitted and the engine mount is still to be refurbished. It is expected that progress on the rebuild of A46-55 will accelerate from here on in. This aircraft is currently owned by Greg and is available for purchase by interested parties in a configuration to suit the buyer.

CA-12 Boomerang A46-77 has also progressed for its Queensland based owner and is awaiting the modification of the Harvard MK IV center section as with A46-55 whilst a host of smaller items are also now being completed to allow for the completion of the fuselage.The fuselage shell for A46-77 has been completed for some time and temporally fitted for alignment of other parts. A Pratt & Whitney R-1830-90 Twin Wasp radial engine is held along with the 23E50 Propeller for this project.

CA-12 Boomerang  A46-92 rebuild schedule has recently been accelerated for its internationally based owner. The wooden shell has had fabric covering applied and is temporarily in place with activity continuing on it to attach most of the metal work progressing at a pace. Again a Harvard Mk IV center section has been obtained and will be converted for this airframe. The forward cockpit frame has also been repaired and is awaiting refitting in place of the current one fitted temporarily.

We will report again as work progresses on this very impressive workshop dedicated to Australia’s own indigenous fighter, the CAC Boomerang. The highlight of this year should definitely be the first flight of Greg’s own “ Boomer” A46-54 .

Warbirds Online extends our thanks Greg Batts and the team at Combat Aircraft Constructions for allowing us access to this unique facility.

© John Parker 2019