If the golden age of the plastic airplane hasnt arrived, its about to. Cirrus is scooping up orders for its SR20, the Lancair Columbia may finally be rolling off the line in numbers and here comes Diamond with the long-awaited DA40-180 Star, a four-place follow-up to the Katana trainer.
If nothing else, the world doesnt lack for choice in four-place, fixed-gear aircraft, leading us to wonder if there are enough buyers to support all the manufacturers who hope to ply this increasingly crowded field.
For Diamond, the DA40 may be a must-do project and its coming late to the party. Diamond has been peddling the two-place Katana to the training market for more than five years, with moderate success.
Nonetheless, the company has found a two-place trainer selling in the $115,000 to $125,000 range to have limited appeal; very few Katanas have been sold to owners for sport or fun flying. The fact that Diamond never certified the Katana for IFR didnt broaden its appeal. All of which leads naturally-and necessarily-to the DA40 four-place, a more versatile design that can do triple duty as a trainer, line rental aircraft or as personal transportation. (If that sounds like a Cessna 172, thats exactly what Diamond has in mind.)
Parked on the ramp, the DA40 Stars looks like an inflated Katana and might as well admit it: For practical purposes, thats what it is. The Star is a clean-sheet design, to be sure, but it borrows heavily from the two-place Katana, conceptually and aerodynamically. Like the Katana, the Star is entirely composite, using pre-preg construction but more carbon fiber than the Katana, primarily for weight and strength considerations.
The Star is noticeably bigger than the Katana but not what youd consider a big airplane, at least by four-place standards. The exception to this is the wingspan, which, at 39.4 feet, shows the Stars not-so-distant antecedence as a motorglider.
Before it made certified powered aircraft, Diamond-then HOAC and before that, Hoffman-made motorgliders at its Austrian headquarters in Weiner Neustadt. Motorgliders still account for a substantial share of Diamonds business.
Like a glider, the Star has high-aspect ratio wings but instead of spoilers, it has two-thirds span electrically operated slotted flaps, with conventional ailerons outboard. Pitch control is via elevator mounted on a high T-tail. (The T-tail is nearly 7 feet off the ramp so any inspection other than routine pre-flight will require a ladder. The DA40 is 25 feet long. As does the Katana, the Star has stick operated push-pull tubes routed through roller bearings for aileron and elevator control, while the rudder is cable operated. For trim, Diamond installed a standard wheel in the center console with a cable-controlled anti-servo tab.
The prototype we flew didnt have electric trim although final versions may have, possibly with a coolie hat switch on the stick. The Katana has only a rocker-switch for electric trim control and given the choice, we would prefer manual trim via the wheel.
One of the odder things about the Star is the cockpit canopy and door design. It has a forward hinged bubble canopy-the Katana is a spring-loaded rear opening design-and a leftside hatch for the rear seat passengers, both of whom enter and exit from over the wing on the left side.
Stretch and Bend
Frankly, this makes the Star one of the more awkward airplanes to enter and exit, in our view. There are two steps mounted forward of the wing, thus entering requires clambering up over the leading edge onto the wing walk and stepping inside, before plopping down in the seat.
The angles and heights are such that theres no easy way to avoid planting your Nikes right on that new leather seat, thence to the floor, whose area is quite small. Getting out is a chore, too, since it requires hoisting yourself forward and up. Old guys with bad backs will squawk. The Katana has a pair of hand grips in the glareshield to help with exit and the Star will get these as well. In the meantime, grabbing a handful of the canopys hinge hardware works just as well, but its still an unnatural movement. Diamond is considering installing a step rear of the wing, but that wont make getting into the cockpit from the wing any more graceful.
Entering the rear seats through the side hatch is easier, since the hatch is quite large and the angles and shape work in the passengers favor. That said, scurrying into this airplane on a rainy day may not be a pleasant experience.
The front canopy especially exposes the interior to the elements so theres no time to dawdle; you need to get in and button down the top as soon as possible and even then, we suspect things will be moist for awhile.
Were not sure how potential buyers will react to this canopy design. Frankly, were unable to judge it without flying the airplane more than we have. It may prove to be more a convenience than an annoyance in the long term.
The canopy hardware and latching mechanisms are sound and easy to manipulate and once inside and latched down, the airplane is quiet and secure. Visibility inside the cockpit is nothing less than astonishing.
The Katanas cockpit view is quite good but the Star surpasses even that standard, since its larger and has correspondingly more cockpit glass to look through. The view up is limited only by a frosted sunshield directly over the pilots heads. The lower edges of the canopy are about at elbow level, giving the sensation of sitting in a fishbowl.
Next question: Will the fish be frying in that bowl on a steamy Florida day? We cant say, since we flew the airplane on a blustery Ontario day when the direct March sunshine was welcome. The Katanas rear-hinged canopy has no ground ventilation position but pilots learn to prop it ajar manually to allow prop blast to make the cabin tolerable.
The Star will have a ground vent position for the canopy and it has excellent interior vents, a couple on the panel and overhead eyeball vents. Theres also a generous storm window and we suspect if this canopy design proves to be a solar oven, a scoop on that opening will help.
The prototype we flew was equipped with leather covered automotive type seats. By that, we mean the contours offer some lumbar support and have back/neck rests.
The seats dont adjust, either fore and aft, nor do they recline. Short-stuff pilots can move the rudder pedal aft, using a small T-handle and cable lock on the pedal/brake assembly, a design we thought worked better than other such attempts weve seen. One thing we didnt like was that the rudder cables are exposed along the cockpit sidewalls. In the Katana Eclipse, these were buried behind side pockets and in an airplane this expensive, we dont want such structural elements exposed.
The brakes are the standard toe mounts and they do the ground steering, since the airplane lacks a steerable nosewheel. Ground handling is very crisp and with one brake locked, the Star will turn on a dime.
Even with limited adjustment, we found the seats to be exceptionally comfortable and well-positioned, although they could so with foldable arm rest between the two seats for long cruises. We tried the rear seats briefly and our impression is that they have generous shoulder room but only adequate leg room. Even at that, toe room has been carved out from beneath the front seats with a couple of strategically placed slots.
The seats have a three-point restraint system-lap and shoulder harness-and are mounted on energy absorbing crushable foam and carbon structures designed to improve crash survivability. Field experience has shown the Katana is exceptionally crashworthy and our guess is that this will apply to the Star as well, despite its higher speed.
As far as we know, the Katana has been involved in only one fatal accident-a VFR-into-IMC encounter-and several in which the airplane was destroyed but the occupants walked, literally. Unlike the Lancair and Cirrus, the Star doesnt have a belly placard to tell rescuers how to extricate trapped occupants should the aircraft come to rest inverted. Nor does it have a secondary means of opening the canopy, as does the Lancair, which has pilot-removable door pins. Emergency egress will be through the rear passenger hatch, which also opens upward. Although the latest round of composite aircraft are undeniably more crashworthy, we think the trend toward canopies and gull-wing doors is less safe than conventional overwing designs, such as those used by Mooney and Piper, whose doors have minimal top fuselage exposure and thus are less likely to be unopenable if the aircraft flips.
But will this matter much in the real world of aircraft accidents? We simply dont know. If all such designs make it through the next five years with no apparent crash safety shortfalls, our concerns may prove unfounded.
As currently envisioned, the Star will come equipped with Bendix/King (nee AlliedSignal, nee Honeywell) Silver Crown Plus avionics, including a KLN 89B or 94 IFR GPS, should the thing ever make it to market. Naturally, Diamond would be insane not to offer Garmin radios as an option, since the market has a clear preference for the GNS 430 color mapcomm.
Diamonds Jeff Owen told us he expects most Stars to be shipped with more than a minimal IFR panel, and that means HSI, storm avoidance gear and an autopilot, a KAP 140 with altitude hold. Whether IFR-equipped or not, all of the Stars built will have the embedded mesh and wiring conduits necessary for IFR certification.
Compared to most four-place airplanes, the Star panel area is smallish; smaller even than older Mooneys. Theres room enough for the required avionics but not too many extras, in our view. Yes, you can fit a large-panel MFD into this cockpit, but it will take careful planning. (The panel is higher on the left side than the right, since the right is arced downward to improve visibility over the glareshield.)
In the prototype we flew, the engine instruments were the same Moritz gauges Mooney is using in its new aircraft, although production versions will have the Vision Microsystems multi-function engine gauge display, an LCD-based system. Our preference is the Moritz; the Vision systems look fine in homebuilts, but not in a $180, 000 certified airplane.
The electrics are controlled with a row of well-labeled rocker switches along the bottom panel, with the circuit breakers mounted far right, as per older Mooneys. And there are a ton of CBs, fully six rows of four to eight each. A set of critical system annunciators are positioned in the pilots scan just left of the radio stack.
Interestingly, there are nine round cutouts in the pilots main scan area, meaning there may be more room for indicators than for the boxes to drive them. For service access, the glareshield pops up, opening up the entire behind-the-panel area. Lighting is both internal and external, using an electroluminescent strip bonded to the underside of the canopy.
Ergonomically, we give the cockpit an A minus, our only serious misgiving being how tolerable it will be in hot weather. The stick, console-mounted throttle, prop, mixture and trim all come easily to hand and the backseat is accessible from forward for retrieving odds and ends.
As currently conceived, the Star has a Lycoming IO-360 engine, the same 180 HP parallel-valve variant used in the Cessna 172 and 172SP.
In general, this engine series has proven reliable and seems a good choice for the Star, in our estimation. For smoothness of operation-not to mention 20 more horsepower-Continentals IO-360 ES would have been a better choice. Indeed, as this project moves forward, that engine might appear as an option, says Diamonds Jeff Owen. We were surprised to note that the engine is equipped with Unisons LASAR electronic magnetos, making Diamond the first airframer to offer this system. Theyre an option, not standard.
The Star prototype we flew had a three-blade MT wood/composite prop, which initial deliveries will be fitted with. Diamond is considering a two-blade prop, which will offer better cruise speed perhaps at the cost of a slower climb rate and more noise. Thats fine by us. We dont like these light props much, since they have no flywheel effect and alter engine response in ways we consider unpleasant.
In addition to the three-bladed prop, the Star prototype also has highly baffled muffler system to meet European noise requirements. Permit us a moment of wild-eyed, frothing at the mouth: We grow weary of airplanes dumbed down to meet ludicrous noise standards in Europe, a sentiment thats spreading to the U.S. like fungus.
We dont want to be good citizens and cooperate with the airport neighbors, we want them to move away and stop their incessant whining about airplane noise. (We now return you to your regularly scheduled article.)
When composites became practical for light aircraft, the thinking was they would allow stronger aircraft structures at light weights. And that would mean little airplanes with greater payloads and range. Made sense on paper, didnt work out in reality.
None of the current crop of composites have exceptional weight-to-payload ratios. All compare favorably but dont exceed the numbers for established metal designs or similar power and weight.
Nor does the Star rewrite the book on that count. The draft manual gives gross weight as 2535 pounds, with typical empty weights estimated to be about 1650 pounds, for a useful load in the 885-pound range, a bit more than the Cessna 172 and New Piper Archer but quite a bit less than the 1180 pounds a typical Cessna 182 will carry.
We ran some weight and balance problems-again, using the draft manual-and found the CG envelope somewhat narrower than a Cessna 172-7.5 inches for the Diamond Star versus 12.5 inches for the Cessna. Both envelopes narrow at higher gross weights and while the Star is generally narrower in CG, it tends slightly to forward outloading, not rearward. With two 170 pilots, full gas and 65 pounds of baggage, the CG is near the forward limit but in the envelope. Fill the seats with 170 pounders and 30 pounds of bags, and youre down to 35 gallons of gas but still in CG. In practical terms, this is a three-person airplane with full fuel and reasonable baggage.
Speaking of baggage, the Star can carry more weight than bulk. The baggage compartment is quite small, although theres an optional ski tube extension that runs deep into the tailcone. The tube is huge and will hold far more than skis but will require feeding the stuff back into the tube and then retrieving it.
Both rear seats fold forward to make this easier. The Stars tanks carry 43 gallons of fuel-42 usable-giving it a still-air range of about 560 miles, with 45-minute reserves, the same as a Cessna 172 but better than an Archer.
Flies Like a Katana
We have to hand it to the plastic airplane makers; theyve paid attention to the handling quirks found in the typical spam can and all but eliminated them. The Cirrus SR20 and Lancair Columbia have superb handling and the Diamond Star can make the same claim.
Its stick forces are light in pitch and moderately stiff in roll, although the roll rate is quicker than youd expect for such long wings. We thought the trim stability was excellent, especially at slow speeds, where its possible to trim the airplane for 60 knots and have it complete a shallow banked turned with no pilot input whatsoever. We did find the rudder somewhat stiff, making the right amount of pressure tricky to calibrate.
Power off stall behavior is identical to the two-seat Katana: It takes effort to hold the nose high enough to provoke the stall and theres no break or fall off, unless aggravated by hard rudder input. The slightest relaxation of back pressure breaks the stall. Published stall speed is given as 49 knots, at gross weight.
In the pattern, the Stars power and long wings deliver a brisk initial climb rate and quick acceleration to 80 knots. (One of the Rotax-powered Katanas weak traits was anemic climb, especially on warm days.) The airplane literally levitates off the runway in what seems a near level pitch attitude. Even in an 80-knot climb, visibility over the nose is excellent.
As in a Mooney, theres a slight nosedown moment with flap extension but its not nearly as pronounced and is easily trimmed off. We found that the airplane trimmed effortlessly to 65 knots for approaches, although in calmer conditions, we would use 60 knots or even 55 at light weights. The Star is the easiest airplane weve encountered to land, bar none. It has little tendency to float and the sight line over the nose makes childs play of feeling for the runway with the wheels.
Because of that bubble canopy, the leftseat pilot never loses sight of the runway so pattern work is like sitting in a living room with a picture-window view of the airport. We predict that the Star will make a first-rate and fun multi-purpose trainer in ways that the Katana hasnt.
Cruise speeds are adequate, but not blistering. At 6000 feet, we recorded a TAS of 141 knots, at about 67 percent power. Not bad but with the three-blade prop, the Star looks faster than it is. With a two-blade prop and some tweaking, 145 knots ought to be achievable.
Worth noting is that the Star we flew-serial number 4-had nearly 1000 hours on the airframe, the result of an intensive Beta test program Diamond conduction in Austria, flying the airplane up to 12 hours a day to wring out potential maintenance problems.
What broke? A mixture cable, an electric fuel pump, a check valve in the fuel system-gummed up, actually-brake pads and, obviously, a bunch of tires.
If Diamond set out to build a composite Cessna 172-at least in terms of overall performance and payload, we would say theyve succeeded with the Star. The DA40 is nearly 20 knots faster, climbs better and uses about the same fuel for the same payload as the Cessna 172.
Comparisons with the Cirrus and Lancair are inevitable in our view, despite Diamonds intent to position the Star elsewhere. All three are low-wing composites with fixed gear. But the other two aircraft are faster, carry more and are significantly higher in price so the Star holds its own in the value equation. You pay less, you get less.
In our opinion, the Star will be a natural step-up for anyone who trained in a Katana or for flightschools in need of a docile four-place IFR trainer or rental. At $185,000 for an IFR-equipped version, its priced with the Cessna 172SP but below the 182.
We think Diamond will have to hold the line on that price; if it escalates above $200,000, a Cirrus or 182 may beckon. As an owner-flown transportation machine, the Star is certainly more interesting to fly than a Cessna 172 or Archer.
Our only misgivings concern the canopy and related ingress/egress issues and hot weather operations. Were not sure how many buyers will find the forward-hinged design and rear hatch too exotic for their meat-and-potatoes tastes.
Otherwise, we think the DA40 essentially delivers on its design brief, even if its a tad slower than promised. Diamonds task will be to find a niche between pure trainers and the uncertain Cirrus and Lancair buyers who want something less expensive but dont like the staid offerings from Cessna and other manufacturers.
contact- Diamond Aircraft; 1560 Crumlin Sideroad; London, Ontario Canada N5V 1S2; 519-457-4010; www.diamondair.com.
by Paul Bertorelli