Diamond’s DA40 – What a gem!
Paul Phelan flies Diamond’s newest four seat trainer/tourer
There’s been a notable turnaround in Diamond aircraft’s sales since Hawker Pacific took on its regional representation, and the well-known Austrian/Canadian manufacturer now enjoys a strong and growing presence in the Australian and New Zealand markets.
Diamond’s biggest-yet sales boost, at least in our region, came with an impressive order from New Zealand’s Massy University, announced at Avalon last March. The (almost $5m) deal was for two Diamond DA42 twins and 12 DA40 singles, with the entire fleet expected to be operating by the end of this year.
The newest offering has been the DA40-XLS, with multiple endearing features. Hawker Pacific at Bankstown had proudly wheeled out its new and well-groomed demonstrator, VH-DIV, and demo pilot Richard Tomlin walked me around the aeroplane. The first impressions are of simplicity and style. The aircraft manages to be very roomy internally while also appearing relatively small and sleek, its all-composite airframe suggesting low drag, and its long tapered and wingleted mainplane also promising glider-like aerodynamic efficiency.
The aircraft is a blend of super-sleek composite structure, advanced aerodynamics based around the relatively high-aspect ratio (10.65:1) of its 12m wingspan and simple but sturdy modern low-maintenance structures and systems. Its design has delivered a truly delightful-looking four seater that is already carving out a market share with private operators as well as flying schools.
The XLS’s fuselage has been slightly stretched in all directions, and it’s powered by a fuel-injected 180 hp (134.2kW) Lycoming IO-360, a totally-proven engine model but now powering a three-bladed MT constant speed propeller and with three-lever conventional controls. In the prop’s low-weight vibration-reducing wood-composite blade design, the wooden core is sheathed in a fibre-reinforced plastic coating with an anti-abrasion stainless steel cladding strip along its leading edges. I was about to find that the three blade configuration produces a markedly smoother sound, and less apparent vibration in all flight regimes, than the old familiar sounds of yester-century.
Maximum power is 180 HP (134.2kW) at 2700 RPM at sea level in ISA, with maximum continuous power pegged at 160 HP (119.3 kW).
Lower drag means a lesser lust for thrust, which translates into improved fuel economy, higher cruise speeds and climb rates per horsepower, enhanced payload/range, and happier accountants. The smooth, flowing, rivet-free surfaces account for much of the drag reduction, the rest being the ease and relatively low cost of building semi-monocoque composite structures in any shape, unrestrained by the higher manufacturing costs that limit creativity in aluminium designs. If you take a look at the beautiful Lockheed Super Constellation almost every fuselage former in that elegant aeroplane is a different size to accommodate its streamlining – which may explain why DC-7s were cheaper to build.
Similarly the wings are formed around robust front and rear spars and bonded sandwich-construction between a top and a bottom wing shell, with built-in standard 76 lit (or optional 94 lit) embedded aluminium tanks with flush over-wing fuelling points. The tricycle landing gear comprises two spring-steel main legs anchored to the main spar but angled outward to a generous 2.97 metre track.
The ailerons, electric flaps (interconnected by a torsion tube), rudder and elevator are of similar construction, while the horizontal stabilisers mounted on the sandwich-construction T-tail have twin spars with no sandwich. Ailerons, elevators and flaps are operated by low-maintenance steel push-rods, while the rudder is activated by fail-safe dualised cables. Ailerons have four hinges, the elevator five, and the three-position flaps, which are notably longer than the ailerons, have a reassuring six hinges. There’s also a long ventral directional stabilising fin, with a hardened ground bumper at its lowest point, to protect the large 0.47 m² rudder in a tail-down flare.
Flap area is over 1.5m2 , maximum landing flap extension speed (VFE) is a reasonably comfortable 91KIAS, while VFE with takeoff flap is 108 KIAS. Manoeuvring speed is also 108 KIAS, and normal approach speed varies with weight between 88 and 71 KIAS. Never-exceed speed (VNE) is a comfortably high 189 KIAS. If all that sounds a bit technical to the average ‘let’s-get-in-and-go pilot’, the numbers are very meaningful in the lives of instructors, who will observe that (for example) flying this very low-drag aeroplane will quickly train students to manage their descents and approaches carefully to conform to normal arrival and circuit profiles – just like the jet they may soon find themselves flying.
So let’s take a look inside.
First, on both sides there’s a small step attached to the firewall just forward of the leading edge to help you up to the non-skid inboard wing walk-way, and there are convenient hand-grips to help you. (Any thoughtful grandperson would probably provide a small kitchen step unit to get Nana and Papa onto the wing a little more comfortably.) The huge one-piece canopy is hinged from the top of the instrument panel coaming, opening upward and forward, so there are no obstructions to front seat entry, which is simply a matter of stepping down into the cockpit using convenient hand grips.
For rear seat passengers a single upward-opening door is hinged fore-and-aft at the fuselage centreline, and getting aboard from the left wing is just as easy. Both doors are amply supported by gas struts, and easy to manipulate while seated, even by untrained passengers. Door locking is super-safe, and the huge forward canopy, when locked in place, becomes part of an extraordinarily strong protective roll-cage structure. Hawker Pacific’ sales executive Stephen Pembro was able to produce some frighteningly impressive images, some of unfortunate events and others in certification tests, that conveyed the awesome survivability of these safety structures – and similar levels of safety exist in all aspects of Diamond’s design.
The cabin designers have thought of everything. Space is ample even for the over-sized pilot or passenger. Seats, being part of the airframe for added structural safety, are not fore-and-aft adjustable because there’s plenty of space. Rudder pedals however can be adjusted on the ground by a process that’s simple once you get used to it (like your new car.) Lateral space is ample for all four seats, and there are thoughtful little touches like foot-insets under the rear of the front seats, which effectively add maybe 20 cm of unexpected foot space for the back seaters who were already doing pretty well anyhow.
The leather seats have high backs, and the upholstery is of luxury sports car quality. Individual control sticks are mounted to the front of the seat between our knees, and left hand operated while resting an elbow on a convenient armrest, with the right hand taking care of the throttle, flaps and avionics. Press to talk, electric trim switch and autopilot disengage are all provided on the LH stick, and there’s a mechanical trim wheel on the console beside the engine controls. Although part of the structure, the carbon fiber/Kevlar hybrid material seats have removable furnishings and the seats themselves can easily be removed for inspection of the underlying control systems. Leather covers on the control sticks prevent loose objects from falling into the control system area.
The park brake lever is also on the centre console under the instrument panel. The lever is pulled downwards until it catches; brake pressure is built up by multiple operation of the toe brake pedals, and stays engaged until the park brake is released by pushing it upwards.
The windscreen is a single wrap-around unit right back to a point behind the pilot’s shoulder unobstructed even by a centre post, giving total visibility in an arc that takes in everything forward of the wingtips’ trailing edge; and the nose is low enough to allow you to see the tarmac about three metres ahead. The overhead section of the canopy is however locked to the rest of the fuselage when the canopy is closed, providing an integral roll cage that extends to a point forward of the front seat occupants’ heads. Once seated and settled in with the three-part harness sorted out, there’s a satisfying level of comfort and ease of movement.
Integrared avionics suite
VH-DIV is fitted with a two-screen Garmin 1000 avionics suite, with the customary trio of conventional dials – A/H, altimeter and ASI, and providing a primary flight display (PFD) on the left with multifunction display (MFD) on the right. PFD and MFD displays can be presented in round-dial or in modern pictorial format at the push of a button, and we choose the 21st Century imagery. The Garmin system also incorporates the optional synthetic vision add-on, which I’m looking forward to seeing demonstrated with real hills around us up Warragamba way. Various presentation formats can be selected for the full engine condition display. A typical display shows manifold pressure, RPM, fuel & oil pressures, EGT and CHT for each cylinder, fuel flow, voltage, amps and oil temp.
There’s a built-in array of warning systems on the annunciator panel for alternator, voltage, fuel pressure and contents, oil pressure, insecure door and other systems, each accompanied by an attention-getting aural alert that directs your attention to the panel, which is tested before flight. Where it’s appropriate, these can be cancelled by pressing the “acknowledge button.”
Between the front seats there are also connectors for up to four headsets, and the avionics system allows conversation between all four occupants to converse in comfort. The pilot can however isolate the audience from interrupting essential radio coms.
Completing the simple pre-start checklist we give the engine a generous Lycoming-sized prime for an easy start, score a taxy clearance, and we’re away. The castoring nosewheel responds splendidly to differential braking with no grab or jerk and just light foot pressure, and does everything I want it to do so keeping on the taxiway centreline presents no problems. This aircraft is as easy to handle on the ground as any I’ve flown. Tight taxy turns can be easily and smoothly executed, but I need to keep reminding myself there’s more than the customary amount of wingspan when I’m close to other aircraft.
The park brake lever is also on the centre console under the instrument panel and is simply pulled downwards until it catches. Brake pressure is built up by operating both toe brake pedals, and stays until the park brake is released by pushing the lever upwards again.
Either during taxying or holding, good cabin ventilation is achieved with the canopy in the “cracked-open” position, and there’s no cramped-up feeling at all, with plenty of clearance between the two of us. With the canopy locked there are still movable ventilation nozzles in the instrument panel. There are also spherical ventilation nozzles in the roll bar on the left and right sides next to the front seats as well as on the central console above our heads. They are opened and closed by twisting.
The intercom, which is part of the integrated Garmin system, is of high clarity and has convenient volume controls so I can choose my own intercom, navaid and VHF volumes and minimise unnecessary background.
Richard operates the Garmin and handles ATC comms while I roll down the taxiway reminding myself to do a Garmin 1000 course while I’m still young enough to absorb new information. As a relative newcomer to this technology level I really enjoy the ability to sit there in a comfortable cabin and watch Richard pushing a few buttons until the entire flight to Richmond and beyond is displayed on the MFD’s nav display. A bit of situational awareness, overworked phrase that it is, never did anybody any harm!
Pre takeoff checks completed in the run-up bay, we’re cleared initially to track to Richmond at 3,000’ for vectoring to Richmond’s Runway 28 ILS, and we’re cleared for lineup.
Maximum Take off weight is 1200kg, for which chart VR is 59 KIAS and best ROC at our weight with flaps at takeoff setting (15°) is 60 KIAS. With full throttle applied, rudder control comes almost immediately making centreline tracking easy. The DA40 doesn’t have to be dragged into the air and rotation back pressure is low, producing a very positive initial climb. We accelerate to 80 KIAS for a better view of Bankstown’s famously busy circuit – although it’s pretty quiet today – and climb rate remains about 1,120 fpm.
Richard wants to show me the full range of autopilot capabilities while I admire the view, so he talks me through engaging the AP in vertical speed mode. There’s no rudder trim and my main role at this point is to substitute for it with a little right foot pressure.
Welcome to automation. The Garmin GFC700 autopilot automatically re-trims itself to make the selected airspeed while locking onto the cleared GPS track and levelling out at our cleared 3,000’ altitude, again re-trimming for straight & level flight. The only pilot input required up to this point is to adjust the engine controls according to the desired flight regime – oooops, and to keep a bit of right rudder on.
We’re vectored and cleared to intercept the ILS at 2,500’, and all we need to do is control the speed with throttle. Large throttle movements are needed to reduce speed in this remarkably low-drag machine, and I reflect that maybe Diamond might be thinking about an upper-wing speed brake, which they already have in gliders.
Even on a clear day, it’s amazing to watch the precision with which this aircraft intercepts altitudes, glideslope and localiser, and we’re soon on final with the runway straight ahead. Breaking off at the 200’ minimum, we’re cleared to track south to the training area on climb to to 6,000’ for some upper air manoeuvring. Elevator trim changes for configuration transitions are modest, and manual handling is a pleasure with light control forces, nicely balanced through all three axes.
I liked this aeroplane from the walk-around and I like it even better as I get to know it. At altitude I explore lower-speed manoeuvring, an often neglected skill aspect in training, and again I find the controls light and responsive, making stabilised straight and level flight and rate one turns easy at all speeds right down to 60 KIAS with flaps 15. Medium and steep turns are also a breeze once I’ve figured out the nose position.
No problems with the unusual
Richard suggests we try a stall or two. The hardest part is losing speed, because this low-drag aeroplane wants to climb at almost anything above idle power, and a straight 1G flapless stall, occuring at around 52 KIAS, merely results in height loss with aileron control still available. In landing configuration I get a similar result but back at about 42 KIAS, and I think I’d have to work pretty hard to achieve anything very frightening. The only criticism I have in this area is that there are probably better aeroplanes in which to teach recovery from more typical stall situations such as wing drops and incipient autorotation (not of the helicopter variety!) It’s also useful to explore a little sideslipping and a sideslip flare in the landing configuration, because that’s what you do in a crosswind and not all aircraft react in the same way. In this case the outcome is reassuring, and although we’re not expecting a crosswind we’d not be concerned if there was one.
All the while I’m noticing very modest cabin noise levels, and a high cabin comfort level that will be apprectiated in cross-country touring, as well as by instructors who have to sit out some pretty long days. Along with that comes some obviously carefully thought-out ergonomics, those unseen attributes that have you walking away after a flight without feeling you’ve been stressed, uncomfortable, or overworked. These comfort issues have real safety and effectiveness relevance, and the DA40 passes with top marks. We didn’t do all that much straight and level, but at various power settings I did observe performance that amounted to something close to 15-20% better than various comparable and mature four seat single-engined types in the 180 hp range.
Another aspect I’d have liked to explore in less-visual conditions is the synthetic vision add-on. Right there on the PFD’s background image, behind the attitude and other data, is a scenic image that actually shows me the hills ahead that I wouldn’t be able to see at night or in cloud, and it’s even fun to watch as the bits of ground turn red to indicate that you’ll hit them if you keep flying the way you’re going.
On the way back to Bankstown I can’t help appreciating the DA40‘s superior pilot vision as well as the way Garmin’s kit highlights any nearby transponding aircraft on our PFD – and the traffic has hotted up a little during our absence. We’re cleared for a couple of touch-and-go’s in only mild turbulence, and as expected from recent experiments the DA40’s handling proves it to be an excellent aeroplane close to the ground. It is responsive, easy to control with precision near the ground, and not at all demanding to achieve a satisfying landing.
There’s no doubt that the DA40 will fit neatly into any training role where the aim is to develop solid stick and rudder skills while also learning to optimise flight using advanced avionics. And this aircraft will certainly also be a very satisfying personal transport for family touring or for the business owner.
Anything else you need to know? Just call:
Stephen Pembro - HAWKER PACIFIC
Phone: 61(2) 9708 8597 Mobile: 61 (0)418 212 124
Email:Stephen.pembro@hawkerpacific.com
