FLYING!

All of the hard work from the previous decades of parts collection and restoration came down to one defining moment at 4.30pm local time on Valentine’s Day, 14th February 2003 at Toowoomba airport, Queensland when A46-122 roared down the runway for the first time since 1945 and took to the air once more. It just seemed surreal….perhaps it was really the Aerotec Boomerang in a different paint scheme!....no it really did happen. Wayne Milburn performed a superb job in conducting the first post-restoration flight of “Suzy-Q”.

Copyright © C.Justo

Many thanks must go to Lynette Zuccoli and the Aerotec crew for their long-standing assistance, not just for their input into the restoration and certification process, but also for allowing me to fly some of their warbird aircraft over the previous ten years, and in so doing, instilling the knowledge and attitudes that go hand in hand with operating this type of machine. This experience over an extended period came to the fore when the time arrived for me to at last fly my own Boomerang. Initially, poor weather delayed this long awaited event, however Friday 7th March 2003 became the day that this dream finally became reality.

Suzy-Q has since attended many airshows, fly-ins and gatherings of wartime Boomerang veterans, receiving a favourable response from all of those who have had the opportunity to see the aircraft up close on the ground, as well as performing an aerial display. To date (Oct 2003) the Boomerang has been displayed at the following venues:

• Caboolture Fly-in
• RAAF Base Amberley F-111 30th anniversary
• Queensland Air Museum open cockpit weekend at Caloundra
• Bundaberg Airshow
• Qld Vintage Aeroplane Group Fly-in at Wattsbridge Airfield
• Qld Vintage Aircraft Association Fly-in at Temora
• Boomerang Veteran Reunion at Hoxton Park Airfield
• Archerfield Airshow
• Warwick runway exstension celebration (above image)
• No 83 SQN RAAF Reunion at Yamba
• Goondoowindi Fly-in
• Scone Airshow
• EAA Toowomba Chapter Annual Dinner at Toowoomba Airport

It is expected that the Boomerang will attend many more events in the years to come.

Click the icon to hear what a Boomerang sounds like overflying at 220 knots. (mp3/228kb)

Flying the Boomerang

CA-13 Boomerang
Wingspan	36'0" (10.97M)
Length	26'9" (8.15M)
MTOW	3492 KG
Range	930 NM
Fuel Cap	160 Imp Gal
Engine	CAC R1830 (Pratt & Whitney) 14 Cyl Radial 30 Litre Disp 1200 HP
Propeller	DeHavilland Australia (Hamilton Standard) 3E50 - 3 Blade, CSU
VNE	360 KT
Run Up	2000 RPM
Take Off	48" / 2700 RPM 80 KT (600 L/HR)
Climb Out	34" / 2350 RPM 140 KT
Cruise	26" / 2050 RPM 160 KT (160 L/HR)
vFlap	110 KT
Base Leg	100 KT
Final Approach	90/85 KT

Many people have asked me what the Boomerang is like to fly. In an attempt to answer this in some detail, I have put together some points from a typical flight:

Pre-Start

Once all of the preflight checks and paper work have been completed, the propeller is pulled through to clear any oil which may have accumulated in the lower cylinders as well as getting a feel for the general engine condition, compressions etc. The cockpit is entered from the left hand side wing walkway, using a conveniently positioned footstep located in the fuselage side. Once seated, you notice that the cockpit is quite ‘roomy’, including armrests just inside the canopy rails and heel slides elevated above the cockpit floor on which to rest your feet. The cockpit floor just visible through the lower fuselage tube framework, ducting, conduits and electrical boxes is actually the upper skin of the wing centre-section.

As the Boomerang’s ancestry finds its roots in the Wirraway and Harvard / T-6 North American Aviation trainer design, the cockpit layout is in some ways similar, with a control shelf on the left hand side which contains the switch for the auxiliary fuel boost pump, the fuel selector, oil cooler exit door control quadrant, elevator and rudder trim wheels, landing gear and flap control levers, manual hydraulic pump and cowl gill control levers, as well as indicator toggles for the landing gear and flap positions. Above this and within easy reach of the left hand is the throttle quadrant assembly which also incorporates the fuel mixture and propeller pitch control levers. The main instrument panel has been installed in “Suzy-Q” as per the original CAC layout, however the sub instrument panel below has been modified to include some modern day concessions….two VHF communications units and a transponder. On either side of the main instrument panel are sub boxes which incorporate such items as the magneto switch, 8 day clock and starter switch.

An original P8 compass and mount nestles between the rudder pedals. As your gaze pans to the right hand side of the cockpit, the main electrical panel occupies the forward area with its many switches, rheostats and fuse panel. Below this is the tail wheel lock quadrant whilst above the main electrical panel another relic from the Boomerang’s past has been installed. This is a morse key switch that operates three identification lights located under the wing centre section, and which are still operational. Further aft is another reminder of its wartime days, this being the IFF equipment (Identification Friend of Foe). The seat height is adjustable by moving a lever on the right hand side of the seat, whilst visible in the cockpit floor on either side of the seat are the fuel tank gauges for the wing centre section tanks.

Start Up

Once settled into the cockpit the pre-start checks can proceed: Switches and radio off, Master on, circuit breakers in, fuel selector to desired tank for start, oil cooler shutter door closed, cowl flaps open, mixture idle cutoff, throttle set, brakes set, call “Clear” and fuel boost pump on. With 15 psi of fuel pressure registering on the gauge, position the right thumb over the starter switch whilst the right index and middle fingers are depressing the fuel prime switch. Depress the starter switch and count nine blades through the windscreen as the engine cranks over, turn the magneto switch to “Both” then maintain the prime until the engine fires shortly afterwards. Move the mixture control to Auto Lean and watch for oil pressure to register immediately whilst keeping the RPM to a low idle for the first 30 seconds. With the throttle then advanced to show 1000 RPM and the propeller pitch lever in fine, the fuel boost pump switch can be turned off and the Generator switch turned on. This is where the aeroplane stays until the oil warms to 40 degrees C and the cylinder head temps to 150 degree C. As such there is plenty of time to do up the harness, put on the flying helmet and gloves, keep a watchful eye on the engine instruments and conduct some initial checks….lower and raise the flaps to test the engine driven hydraulic pump, open and close the hydraulically operated cowl flaps, select different fuel tanks and generally concentrate all thoughts on the immediate task ahead.

Taxi

With temperatures in the correct range it is time to taxi but with caution. The Boomerang has a very high and broad nose due to its tail wheel configuration and large radial engine, so direct forward visibility does not exist. The only option to navigate safely past cone markers and other aircraft is to weave from side to side during the taxi to ensure a clear path ahead. At the run up bay the nose is pointed into wind, cowl flaps partially closed to reduce air loads on them, scan the instruments again, move the mixture lever to Auto-Rich, hold her on the brakes then conduct the engine run-up…..time to exercise some of those 1200 horses. Select the desired fuel tank for flight then throttle up the engine gradually but smoothly to 2000 RPM which should indicate field barometric pressure on the manifold pressure gauge. Check the magnetos, both left and right for mag drop, cycle the propeller (from fine to coarse pitch and back again) to get the oil circulating through this assembly and checking the RPM decrease during this operation, then retard the throttle way back to check the idle RPM. Bring the engine back up to 1000 RPM and open the cowl gills. Complete the cockpit checks: Elevator and rudder trims set, throttle friction, mixture rich, mags both, fuel on desired tank (still), flaps up, prop pitch fine, air speed indicator glass intact, altimeter set to QNH, full and free movement of the controls, canopy fully open, harness secure.

Take Off

Copyright © Glenn Alderton

Moving onto the active runway and lining up it’s time for those final pre-takeoff checks: mixture rich, fuel boost pump on, cowl flaps three quarters closed, oil cooler shutter door closed, roll the aircraft forward to straighten then lock the tail wheel and all should be set to go! Now to concentrate on keeping straight down the runway as the throttle is advanced and the noise up front gets louder! At the appropriate rolling speed and counteracting any tendency to swing with sufficient rudder input, the tail is gently raised until the carburetor intake scoop on top of the engine cowl is just above the horizon. This gives the Boomerang a slightly tail low attitude, allowing it to fly off when it’s ready. By now the throttle lever is at the stop with 48 inches manifold pressure and 2700 RPM whilst enjoying the acceleration as the speed builds rapidly. At around 80 knots the Boomerang wants to fly. Moments later, having left the ground and with a positive rate of climb established, the left hand leaves the throttle lever and moves the undercarriage lever on the left hand shelf to the rear to retract the landing gear. Left hand back to the throttle quadrant and start to bring the manifold pressure and tachometer gauges in stages back to 34 inches MP and 2350 RPM as the aeroplane climbs out at 140 knots. Check that the undercarriage transit lights have gone out and that the gear indicator levers show both up, then bring the undercarriage selector lever back to the neutral position.

Cruise

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As desired the engine power is then further reduced to cruise settings of 26 inches and 2050 RPM. The fuel boost pump can now be turned off as the Boomerang sings along in level flight with cruise power giving 160 knots indicated air speed, the mixture also being leaned as appropriate. A check of the oil pressure gauge shows it sitting solidly on 80 psi and perhaps slight adjustments are needed to the cowl flaps to maintain a cylinder head temp in the order of 200 degrees C as well as to the oil cooler shutter door to hold the oil temps between 60 and 90 degrees C, this usually being stable around 70 degrees. The canopy can be closed to reduce some noise and slight turbulent air in the cockpit, but it can be left open if desired to take in a magnificent uninterrupted view. By sliding the canopy forward to the last notch in the canopy rail before it is fully closed (leaving about a 50mm gap between the canopy and windscreen frames), enough cooling air is still permitted to enter the cockpit and it makes map reading a more comfortable exercise. Close the canopy fully from here and two things will happen the nose will rise slightly as the small amount of lift generated by the upper curve of the canopy moves forward (therefore necessitating a small elevator trim change) and the temperature inside the cockpit starts to increase, reminding you that you have a 30 litre engine generating lots of power and residual heat only a short distance in front of you.

As mentioned earlier, visibility from the Boomerang in the flying attitude is excellent, with the stubby camouflaged wings complete with roundels, machine gun ports and cannons protruding from the leading edge as well as the vibration of the R1830 up front being constant reminders of the sort of beast that you are piloting. Control inputs are very positive with the ailerons being lighter than the rudder and elevators. The Boomerang has a very powerful rudder and the skid ball should be checked from time to time to confirm that the aeroplane is in balance, particularly during maneuvers and attitude changes. Spectators on the ground can usually hear the whistling noise generated by airflow over the open machine gun ports some time before they actually pinpoint the aeroplane in the sky, however this noise is not heard from the cockpit during flight, except during steep turns. During the war these gun ports were normally taped over with cloth to keep contaminants out of the machine gun barrels, but the ground crews knew if the guns had been fired during the sortie if the whistle could be heard on the Boomerang’s return to the airfield.

Copyright © Glenn Alderton

The Boomerang also has quite a pronounced ‘step’, whereby the aeroplane flown with a slight tail down attitude will induce extra drag and decrease the indicated cruise speed to 155 knots with little height gain. Conversely if a small forward pressure is applied to the stick whilst the aeroplane is trimmed for level cruise flight at 160 knots, the speed will climb to 165 knots with only a minimal rate of descent. A cruise power descent at 500 feet per minute will soon achieve an indicated airspeed of 185 knots. Being such a rare and historic aeroplane, I do not subject the airframe and systems to anything more than moderate aerobatics, so a few gentle aileron rolls are well handled by the Boomerang. It does these superbly with its effective and fairly light ailerons. Bring the power up to at least 2300 RPM and 30 inches manifold pressure whilst at altitude, have at least 180 knots ‘on the clock’ during the maneuver, raise the nose slightly, check and roll with full aileron deflection, allowing the nose to gently drop throughout the roll. When upright again with wings level, the nose which by now is slightly below the horizon, can be raised to the level attitude again. For most display routines, the engine settings are left at 34 inches and 2350 RPM.

Landing

Copyright © Glenn Alderton

Being mindful of fuel consumption which at take-off power is in the order of 600 litres per hour and at cruise settings 160 litres per hour, it is machine in which you normally set out with a specific task in mind to accomplish, whether it be flying enroute to a display or practice for an exhibition routine. As such the time soon arrives to set up for an approach and landing. In order to prolong engine life it is best not to “split the needles” too much in the lower power ranges, so in an attempt to slow the aeroplane down the power settings are brought back to 19” MP and 1900 RPM. At 130 knots indicated the undercarriage selector lever is moved forward smartly, the gear unlocks and drops out of the wheel wells. A clunk on either side, two green down lights and visual indicators in the wing surfaces confirm that the wheels are down and locked. Return the gear lever to the neutral position. The added drag helps to slow down the aeroplane further and at 110 knots the flaps can be lowered a few notches. With

Copyright © C.Justo

downwind checks completed the turn onto base is commenced at 100 knots and the pitch control lever is gradually moved to the fine position. A few more stages of flap and the turn onto final should see the Boomerang with 90 knots indicated and flying down the required glideslope for the runway threshold. Any changes to the glideslope angle are accomplished with small throttle movements. Perform the PUF checks on mid-final (Propeller pitch fine, Undercarriage down and locked, Flaps as desired). Full flap at this stage will normally assist with providing a slower touchdown speed as the Boomerang crosses the boundary fence at 85 knots. All energies are now concentrated on judging the flare and touchdown for a preferred “wheeler” landing (touchdown on main wheels first with slight tail down attitude).

Copyright © C.Justo

At this point any trickle of power left on at touchdown is removed by reducing the throttle to the idle stop and allowing the aeroplane to bleed off its energy whilst keeping straight down the runway. No brakes are applied until the tailwheel has been gently lowered to the runway, the high nose now blocking all forward view. Time for judicious use of the brakes as all you have available to keep straight is good peripheral vision, and an inner thought that you are thankful to have remembered to have locked the tailwheel just prior to take-off. With the aeroplane now at an almost complete standstill and ready to turn off the runway, the tailwheel is unlocked and the taxiway entered. After-landing checks can now be completed: turn off landing lights if used, identify the flap lever and raise the flaps then centralize the lever again, turn off the fuel boost pump, open the engine’s cowl flaps, open the oil cooler shutter door and ease the shoulder straps so that you have at least half a chance of seeing what is ahead of you as you weave your way back up the taxiway.

Once parked, turn off the avionics master switch, check oil pressure at 800 RPM then bring the power back up to 1200 RPM. If stopping for long periods move the pitch control lever into coarse whilst maintaining RPM then move the mixture lever to idle cutoff. The engine now starved of fuel winds down to a stop. With the propeller now motionless and the silence deafening the magnetos are switched to OFF as are the Master and Generator toggle switches. As the harness and helmet is removed and you exit the cockpit, all of the good feelings of having just completed another flight in this amazing and historic Australian designed and built flying machine of 60 years ago start to wash over you…..yes all the years of effort to bring it back to life were well worth it!