Boomerang

Broadly similar in appearance to a Tomahawk, the Boomerang is a little bigger, much stronger and, best of all, it has lost that 1970s T-tail. Construction is all-metal, and mostly of conventional semi-monocoque stressed-skin, using corrosion-resistant 6061- T6 aluminium, although the cockpit area is a sturdy 4130 steel tubing cage to protect its occupants. This incorporates two very strong, two-inch rollover bars, one around and above the windscreen, and the other immediately behind the cockpit, affording 12g of forward protection, rollover, and side intrusion protection. The whole is sheeted with non load-bearing aluminium panels and finished in top quality two-pack paint for maximum protection.

This modular construction allows simple disassembly for overseas shipping or major repairs. In the light of experience, the Boomerang has been designed to keep required maintenance to a minimum, but to make this easy when it is required, thus minimising running costs. Capital expenditure is comparatively small too, at $172,000 apiece ex-factory. So confident is Dean Wilson Aviation, that the company will give you a 50 per cent trade-in price against a brand new Boomerang after five years. Long term lease options are also in hand.

The Boomerang’s single-spar, parallel-chord wing is unconventionally bolted to the fuselage

With what is, to be honest, a pretty lowpowered engine, I was surprised to feel a real push in the back when I opened the throttle.

via its root ribs, rather than as a direct connection with the spar. Integral tanks carry 151 litres of fuel, of which 139 litres are useable, giving a massive six hour endurance at the average consumption of 25 litres per hour. Big, rod operated, single-slotted flaps (much larger than a Tomahawk’s) are extended electrically, with an infinite number of deflections available down to 40 degrees, while low drag, undercut carbon fibre wingtips finish the ensemble.

Both the fin and tailplane are twin-spar structures, and the tailplane’s leading edge is set well aft of the rudder hinge line – a very good thing for spin recovery and other high alpha handling. All flying controls are conventionally operated by stainless steel cables, with mass and horn balances on both elevators and rudder but just mass balances on the ailerons.

For extra safety, every movable surface has more attachment points than usual, with three husky hinges for the rudder, four hinges for each aileron and no fewer than six hinges on the elevator. The elevator trim is also unusual.

There are no tabs on any control surface, but a torsional rubber spring bias is housed in the rear fuselage and tensioned by a conventional trim wheel and linear indicator in the cockpit.

The wide-track main undercarriage uses two strong, tapered, steel spring leaves mounted on rocking blocks in the wings (rather than close together under the fuselage), while the longstroke, heavy-duty nose leg has a conventional nitrogen/oil oleo, with direct linkage steering.

The 600 by six main wheels have the usual differential hydraulic disc brakes, and the whole undercarriage is more rugged than on earlier aeroplanes so that it can easily cope with rough airfields and strips.

Eschewing the disadvantages and high revs of diesel or Rotax engines, the Boomerang uses the same conventional, reliable and well-known 118hp (88kW) Lycoming O-235 as its American predecessors. A 125hp (93kW) version is available (albeit with slightly reduced 1800 hour TBO), while an O-320 powered 160hp (119kW) version with constant-speed propeller is on offer. The cowlings are a combination of lightweight carbon fibre and sheet metal. Latched with two sturdy external catches incorporating Camlok fasteners on each side, these open fully to lie on the flat bonnet top and allow unhindered access and inspection.

Seen beside a Tomahawk, the Boomerang sits a little higher off the ground, but the steel step at each trailing edge gives you an easy hop up on to the wing-root walkways from which you can step down into the cabin. The twin car-type doors (rather than a true canopy) are more wind-resistant, make entry easy, and keep the seats dry in the rain. These seats are deeper to meet the recent, increased vertical deceleration (crash) requirements, so the occupants sit nice and high, with a good all-round panorama, although the forward view is perhaps little better than on other aeroplanes, thanks to an upper cowling which slopes somewhat less than its predecessors’ and a single, central, raked bracing strut to the windscreen.

The Boomerang’s no-nonsense cockpit is both functional and conventional, with no weird finger-operated brakes, strangely placed throttles, starting chokes, or other non-standard oddities. Being both higher and wider than a PA-38 or Cessna 152, there is plenty of head and shoulder room for both occupants, and the fixed (ie, not inertia-reel) four-point harnesses have been tested to withstand a whopping 26 g impact. The trim is admittedly basic, but more luxurious options will undoubtedly become available and, as Min says, “You need to be able to wipe off the vomit easily,” before quickly adding, “But nobody’s ever been sick in my aeroplane, and you can quote me on that. ” So I did.

Dual padded yokes protrude from the black instrument panel which holds the ‘standard six’ VFR dials and gauges directly ahead of the pilot. Unfortunately, experts determined 30 years ago that semi-matt light grey was the best colour for panels. Over on the left are

The Boomerang’s ailerons are comparatively light, and some rudder is needed for all turns (perhaps an inch of pedal deflection for a medium turn) but that is perfect in a trainer.

a clock the ADF dial, with primer and key-operated magneto switch below, while above and slightly to the right of the main instruments is a row of four amber and red lights warning of low oil pressure, alternator failure, low fuel pressure and an impending stall. I would have preferred to see the suction gauge positioned between the vacuum-powered instruments (AH & DG) but it is below and to the right, rather out of your IFR scan – bad, that.

The tachometer is at top dead centre of the panel, with the main radio stack below it (including a moving-map Garmin GNS 430 GPS as standard) and secondary engine and fuel gauges at the bottom. Identical plungers for the carburettor heat and parking brake flank these, with the flap selector and its indicator to the right. The ADF and transponder are in front of the instructor (or passenger) with a carbon monoxide detector, the ammeter and cabin heat plunger over on the far right. Circuit breakers for the 12-volt system are grouped in the bottom right corner, and the five electrical switches are below and to the right of the left control yoke. Finally, the panel is flanked by a couple of swivelling fresh air vents. IFR instruments and avionics are available, with a full EFIS cockpit as another option.

Centrally below the panel, a neat grey quadrant carries the throttle and mixture levers with an adjustable friction control on its right flank. The throttle moves fully open when the friction is loosened (or the cable breaks) – a good safety feature, and the mixture lever needs pulling back through a positive detent to stop the engine – both nice touches.

Moving lower, this quadrant morphs into a slim central console. This holds the rotary left/right/off fuel cock, which has a simple strip of spring steel as a baulk to prevent inadvertent selection of the off position, and the neat pitch trim wheel with its indicator. A stowage area behind the seats will carry up to 20kg of baggage, and there is a fire extinguisher on the floor ahead of the right seat.

The forward rollover bar is handy for pulling your seat forward. Height, tilt angle and back rake are not adjustable, but both seats slide one foot fore and aft on two sturdy steel rails with very positive stop pins operated by a lever below the front of the squab. The harnesses are attached to the airframe rather than to your seat, so you need to adjust the seat before strapping in. Each harness has four separate adjustments, one for each strap, which seemed a little unwieldy, but the result was both comfortable and very secure.

The cockpit has loads of headroom; both occupants could wear air force bone domes without clashing their heads together. Like a Tomahawk, the roof is solid, so you don’t get sunburned.

The wraparound rear panel is an inexpensive single-curvature perspex sheet, as are the door windows, and all transparencies can be obtained in a variety of tints. To close up, you gently pull each door shut, push down its locking lever, and then secure the Piper-like overhead latch. There is no slamming needed here, and production doors were recently stiffened and strengthened, with re-positioned armrests.

With an empty weight of 622kg, this, the first airframe sold, was not-unexpectedly a tad overweight. Nevertheless, within its 825kg maximum takeoff weight it would easily lift myself and Min plus 90 litres of fuel (equivalent to a 152’s full tanks, or over three hours worth). True production airframes are expected to be able to lift the full 151 litres of fuel (30 litres more than even a PA-38) with the same payload.

What can I say about starting a Lycoming? Nothing, so I won’t – it just starts. Both occupants have differential toe brakes, and there is a separate parking brake. Releasing this and addinga puff of power got us rolling away from our grassy tie-down, and once on the tarmac I was able to throttle back to near idle. The nosewheel steering is direct (with no intervening springs) and thus feels more positive than on some American aircraft. The brakes and turning circle are just as you would wish, so there were no surprises, although cabin ventilation on the ground was perhaps a little less than optimum. The air inlets are currently in the forward fuselage sides; re-siting them to behind the outer propeller disc (in the fin or wing leading-edges) should greatly improve cockpit air delivery.

Takeoff from a hard runway is made flaps-up, and the trim wheel is not set to neutral, but to a red dot a centimetre behind this. With what is, to be honest, a pretty low-powered engine, I was surprised to feel a real push in the back when I opened the throttle. Accelerating down the centreline, I noticed a need for right rudder as I gently took the pressure off the nosewheel, but then we did have a 10kt crosswind. The Boomerang’s maximum demonstrated crosswind is 12kt, and it handled our conditions with ease.

Min suggested we rotate at 60kt, to climb at 70 (for improved cooling and forward vision, plus commonality with the Tomahawks on her fleet, despite the Boomerang’s true ‘best rate’ climb and glide speed being 67kt). Unlike the Tomahawk, however, there was a crisp feel to the Boomerang’s elevator, and rotation was smooth and steady, with none of the Tomahawk’s sudden bite when its T-tail comes down into the propwash.

We were airborne within 15 seconds of applying power, passing 500ft in under 45 seconds, and 1000ft in 1:45, although to be fair this spirited performance was helped by a breezy 15kt ground level headwind. Dean Wilson quotes sea level climb performance as a gradient of 8. 6 per cent or one to 11. 6. I make this 566ft/min, and very close to what we achieved on a cool, ISA day. Presumably because of a different wing incidence, the Boomerang’s climb attitude is rather more nose-high than a Tomahawk’s, and you do need a little constant rudder pressure to keep the slip ball centred throughout the climb.

Levelling at 3000ft and setting 75 per cent power gave us an IAS of 88kt, according precisely with Minovation’s flightplan TAS of 90kt with an average consumption of 25 litres per hour. Even down at 1500ft, and with a conservative 2300rpm set, we got a steady 85kt IAS.

As Min said, it’s not designed to be a fast aeroplane, but a trainer, and as such it is ideal. The Boomerang is smooth and stable in cruising flight, and visibility is excellent for map reading, even downwards despite its low wing, and partly thanks to the doors’ low windows – and their new armrests are in precisely the right place for comfort.

Min also praised the Boomerang’s high temperature performance. Even on the hottest WA days, with air temperatures well exceeding 40°C, which ground some other light aircraft, its oil temperature never exceeded 82°C – well within limits.

Incidentally, another modern training type repeatedly has its EFIS fail in high temperatures, again grounding it because, if you don’t know your engine temperatures, you cannot know whether they are being exceeded.

General handing is lovely. The Boomerang’s ailerons are comparatively light, and some rudder is needed for all turns (perhaps 2cm of pedal deflection for a medium turn), but that is perfect in a trainer. Okay, so it doesn’t have an Extra’s roll rate, but it rolls well for an un-tapered wing, and it’s a little beauty to throw around the sky. Yes, it has yokes which I generally don’t like (and these had loose padding, making them woolly to hold, although by now this will have been fixed), but it handles more like an aeroplane with sticks.

Perhaps it’s not quite a Chipmunk or Stampe, but nevertheless, it’s responsive and light. Despite its unorthodox pitch trim arrangement, at no time didthis feel in any way different to a conventional elevator trim tab.

DW 200 BOOMERANG

(technical specifications)
Powerplant
One normally-aspirated,
four-cylinder,
horizontally-opposed
Lycoming O-235-N2C
producing 118hp
(88kW) @ 2800 rpm.
TBO 2400hr. 125hp
(94kW) Lycoming
O-235J2A with 1800hr
TBO is optional.
Propeller: 180cm (71in)
diameter, two-bladed,
all-metal, fixed-pitch
propeller.
Performance
(Manufacturer’s quoted)
Sea level Vne 152kt
75% cruise 95kt
Stall, full flap 46kt
Sea level climb rate
566ft/min
Max endurance 6hr
Weights
Equipped empty 622kg
Max takeoff 825kg
Max baggage 20kg
Standard fuel 151 ltrs
Load factors +4.4/-
2.2g
Dimensions
Length 6.46m
Wing span 9.80m
Wing area 13.7m2
Manufacturer
Dean-Wilson Aviation
Ltd, PO Box 452,
Kingaroy, QLD 4610
Website
www.dwaviation.com
Price
Featured aircraft
A$172,000

My tape clearly says. “This is such a sweet aeroplane” and, rolling out of a steep turn, I was sorely tempted to pull up into a loop. Min dissuaded me, saying, “I don’t do aerobatics. I’d rather stick a pencil in my eyes! Look I’ve got one here ready”. So I didn’t. However, when it has spinning clearance, I am looking forward to getting stuck in.

At 3000ft we ran through our HASELL checks and tried a little slow flying for the engine to cool. Control response is still excellent at 60kt, with even lighter pressures, as you would expect. Continuing the deceleration and trimmed to 60, the high-pitched stall tweeter starts at around 59kt, followed by the merest shiver of buffet at 55, and a fair amount of sink (with the additional aural prompt, “Recover, recover” coming from my right).

Pulling as hard as I could, and with the yoke hard against the back-stop, it was impossible to induce a proper g-break (nose drop). Sweet as ever, the mere application of power and reducing the backpressure immediately got her flying again.

The flap selector switch is spring-loaded to the down position, but locks in position when selected up. The Boomerang’s wide-chord flaps cause a big pitch-down on deployment, although this barely needs trimming out, since the aeroplane continues flying at much the same speed, just with a lower nose attitude.

Unfortunately, the early flap motor fitted when I flew the aeroplane did not have the power to run them to full deflection, even at an airspeed significantly below the 80kt flap operating limit.

This shortcoming has since been rectified with a stronger motor.

Nevertheless, Minovation generally recommends limiting flap extension to below the maximum speed, and its students usually land with just 15 or 20 degrees of flap. This is because all that drag just isn’t needed except for short field landings, and it complicates their arrivals by making the hold-off too short for a student to accomplish the required fine height adjustments before running out of airspeed.

With full (40 degrees) flap – or as near as we could get to it thanks to that weak motor, we got the horn at 50kt, and a real stall at 47kt with a small right wing drop. Again, this is a good trait in a trainer, and those numbers were just what the makers claimed, with both improved stall handling and performance over the old Tomahawk.

Min’s circuit power is 2300rpm, reducing to 1500rpm with 10 degrees of flap as you turn base, then making the approach at 70kt, and reducing this with a little more flap (up to 20 degrees) on short final to 65kt. Even with less than full flap, you do need to pull hard on the yoke during the hold-off to make a proper mainwheel-first landing and prevent a sudden drop in that final second. Min recommends not just chopping the power in the flare, but closing the throttle gently, to lower the aeroplane softly to the ground. As she said, “If you just chop the throttle, it will go kerlponk onto the ground, like an old Arrow. ” This need for a little finesse is another good trainer trait, but easily mastered, and I have to admit my first attempt went well, with a gentle, nose-high touchdown with the stall-warner howling, right among the piano keys. Quickly retracting the flaps and opening the throttle got us back into the air in a second for another go, which went just as well. The only unusual characteristic I noticed on our full-stop landing was an inability to hold the nosewheel off the ground for very far, thanks again to that limited elevator authority.

The subsequent photo shoot was also a pleasure, the Boomerang again proving its responsiveness and nimbleness. I thought it nicer to fly and easier to position in formation than a Tomahawk, Cherokee, Archer or any Cessna.

My only (small) comment was a slight lack of rudder power in the sideslipping head-on shots and peel-aways, even at close to the 110kt Va (its Vne is 152kt).

Now fully certified in the normal category to FAR 23 (after the usual mammoth and financially punishing struggle against the certifying forces of evil), certification is anticipated in the utility category, to allow spinning. Significant orders have already been received from a number of Australian and Indian flying training schools, and the Boomerang comes with a two year or 1000 hour guarantee on Dean Wilson manufactured components. Despite there being a great demand, DWA’s factory offers to provide your Boomerang within four months from initial order placement.

I have to confess that I liked the Boomerang.

It would make a nice private plane as well as a good trainer. It doesn’t fly itself, like a Cessna, which I believe to be a good thing in a trainer, and it has far better external visibility. It is clearly tougher than a Tomahawk, with more interior space and a better short, rough field capability, and it felt like a bigger, more stable aircraft. Its performance with the basic O-235 engine is fine, and with the higher-power version, or better still, with the projected O-320 Lycoming, it will be impressive. There were a few details that could be better, but they were all small. The manufacturer clearly listens to constructive criticism, and several improvements are already in the pipeline.

I predict that the bigger engine will engender a larger fin, enhancing directional stability and helping to control a slight tail dance evident in turbulence at lower levels. In addition, spinning certification will almost certainly call for a broader-chord rudder – another potential overall improvement. Otherwise, I believe this airframe is well sorted, and clearly built to last.

I reckon Dean Wilson has a real weapon in the current trainer-replacement war – especially if your Tomahawk’s spar is getting tired. If you would like to fly this one, contact Minovation on (08) 9414 1064, email: [email protected], or visit to: www.minovation.com.