Late last November, Pipistrel founder, Brainstormer In Chief and head honcho, Ivo Boscarol, announced a major new aircraft project—the Alpha Trainer. Boscarol, widely respected for scheming up bold visions, then motivating his crack Slovenian team of designers, engineers and fabricators to bring them to life—no matter how ambitious they seem—made three big promises about the Alpha:
1. It would debut at Germany’s big Aero show in the Spring of 2012.
2. It would begin production a month later.
3. Its price would be $85,000 complete, including full instrumentation and a GRS airframe parachute system.
Now, sky-high ballyhoo isn’t uncommon in aviation, whereas follow-through decidedly is…unless your name is Ivo Boscarol. His Alpha report card delivered straight As: The S-LSA did debut at Aero and begin production in May— but it missed its price target…it’s cheaper! At $83,995 ($89,000 after shipping and setup), the price alone makes for one of the true value stories in all of light sport.
Yet the Alpha story goes way beyond economics. Its all carbon-fiber composite airframe derives from the same basic wing and fuselage as the Virus SW (Short Wing) speedster which, depending on engine, cruises at 147 knots—at a 3.6 gph fuel burn! Virus has won NASA efficiency prizes for its spectacular efficiency.
Pipistrel optimized the SW airframe to serve a training/sport-cruising mission by dropping in a Rotax 912 80 hp power plant, removing the speed brakes, propping it down to meet the LSA speed regime with a wooden/metal-reinforced two blader, and beefing up the composite gear to handle training hard knocks.
The result is a sleek, beautifully tuned trainer cum cruiser with impressive credentials: 108-knot cruise on just 80 hp with a conservatively spec’d fuel burn of 3.5 gph, 17:1 glide ratio and a full-fuel (I’ll say it again: full-fuel) payload of 507 pounds—enough for four hours/390 miles of flight with two, 250-pound passengers aboard (30-minute reserve). Contrast that with Airplane C, a well-known, $150,000 S-LSA that can only manage an anemic 337-pound full-fuel load.
Pick Me, Teacher!
At Oshkosh, I had the good fortune to be one of the first U.S. aviation writers to fly the Alpha. This new affordable S-LSA not only lives up to its advance hype: It exceeds it. I also think of it as a breakout aircraft that has an important lesson for the light-sport industry. That lesson: small, adventurous, innovative, stay-hungry companies will lead the way.
Pipistrel was a bit of a sleeper in the U.S. market until fairly recently. The Slovenian company has built quality, advanced-design, superb-flying composite aircraft for years now. And this is the same lean, mean band of innovators who won NASA’s $1.65 million Green Flight Challenge last year with its Taurus Electro G4 electric-powered aircraft. The G4 averaged more than 100 mph for two hours on the equivalent energy of less than one gallon of gas per passenger! Given current electric power technology, that staggering feat alone amply demonstrates Pipistrel adaptability and brilliance as an organization.
In the Alpha Trainer, the company displayed its confidence by taking a years- proven planform—the glider-sleek wings and bullet-shaped profile of the Virus and Sinus—and recrafting it into an all-purpose, economical, amazingly low-priced aircraft.
Alpha is no stripped-down, trainer-only LSA either. Seriously now: How many aircraft do we have in any aviation category that cruise at 108 knots on a fuel burn of 3 to 3.5 gph (auto or Avgas) and 80 hp? Yet Alpha still climbs out at better than 1,000 fpm. Even with our all-up demo flight load of 400 pounds and a full 15-gallon fuel load in the fuselage tank, we climbed at 900 fpm…and that was at 90 knots, on a warmish, humid morning, in a new airplane and engine not yet broken in. Yeah. Alpha’s got serious chops.
There’s more than enough performance here for students in the pattern, and touch-and-go, pattern-work fuel burn is around 2.6 gph.
Speaking of cruise, some performance specs for Alpha appear to be a tad conservative. Take the published 3.6 gph at 108 knots at 5,000 rpm. At charming little Brennand Air Park north of Oshkosh, I met a gaggle of graduates from Purdue University’s vaunted aviation program. These young hot sticks have been doing some teaching in the Alpha for Don Sharp, Pipistrel’s Midwest dealer and a 30,000-hour CFI/pilot himself. Sharp got the first U.S. Alpha. All the Purdue boys say Alpha’s fuel burn at cruise is more like 2.8 to 3 gph.
Alpha received its ASTM-conforming S-LSA certificate at Oshkosh. I flew it the very next day. Simply put, it’s a dream to fly. Launching out of Brennand (dimensions: 2400×20 feet—no way. It’s more like 16 feet!), demo pilot and CFI Sean Looloian showed me the ropes during an hour’s worth of air work. We did approach, departure and accelerated stalls, slow flight, Dutch rolls, high-bank turns and roll reversals, and topped it all off with landings at dinky little Brennand—a landing challenge in any aircraft.
The cockpit is well organized. I love the new, bright and clear analog/digital 31⁄8-inch steam gauge-style instruments. The sufficiently roomy panel forgoes a big EFIS screen in favor of those round gauges, Garmin Aera 500 portable GPS in an AirGizmo dock, Garmin GTX 327 transponder, ICOM IC-A210E radio and 406 MHz ELT.
The rudder pedals are adjustable in flight. My only nag is the seat padding, which didn’t support the lumbar area and was noticeably uncomfortable for my tailbone. Tine Tomazic, Pipistrel’s R&D/test-pilot wizard, told me the seat has already been redesigned and will incorporate better support.
Visibility for a streamlined, high-wing aircraft is plenty good—forward, overhead, to the side and even to the rear. The cruise attitude is slightly nose down so the over-the-glare shield sight picture is excellent. To the sides, my eye level was about six inches below wing bottom (I’m 5’11”). The overhead window is placed perfectly to provide excellent topside views around a turn. As mentioned in my Virus pilot report previously, the overhead spar carry-through presents a bit of a forehead obstacle for taller pilots. Sitting in the cockpit will be important in evaluating Alpha’s potential for you.
In flight, thanks to its glider-ish pedigree, Alpha flies like a dolphin swims: joyfully,nimbly, beautifully. It’s fully alive in the air. I felt right at home as soon as I took the controls; this is what a clean sport aircraft should feel like.
Some specifics: Roll rate (45-to-45-degree bank=2.0 seconds) is phenomenal. Roll pressures are two-finger-light. Pitch/roll/yaw are beautifully harmonized. Rudder control is highly effective with minimal input. Only modest pedal deflections make Alpha dance beautifully in yaw. In fact, the Purdue pilots told me their Alpha students learn from Lesson One that less is more: gentle, smaller-range control inputs are considered de rigeur.
Alpha’s glider-slippery airframe teaches energy management in a hurry. I dove slightly coming out of a turn at 93 knots and we sped up to107 knots, just like that. The Alpha will make a conscious, Fred Astaire-style pilot out of anyone: There’s no need to yank this bird around the sky like a ham-handed, wooden-footed dancer. Graceful manners beget superior results with this lovely bird.
The airplane exhibits almost no adverse- yaw tendency even with fast stick deflection, yet good rudder skills do enhance performance and overall enjoyment. Once at cruise, a tap on the electric trim switch and Alpha holds its position like a rock. That’s also true of turn performance: Bank to 30 degrees and it stays at 30 degrees, with neither over-bank nor roll-out tendencies—another trait that will serve students and experienced pilots well.
Indeed, my benchmark LSA for all-around enjoyable, crisp, smooth, intuitively “right” handling has been the Remos GX—until now. The Alpha is my new Main Squeeze.
All Pipistrel aircraft have true soaring potential. And although the Alpha isn’t marketed as a motorglider, the 17:1 glide ratio is nothing to sneeze at. There’s no reason, on a soarable day, you couldn’t throttle back to idle to catch a thermal or a cloud street and cop some free energy.
Manage That Energy!
The Alpha stalls only with the greatest reluctance, at roller-coaster-like high deck angles and with benign docility even then. Easing the stick forward gets you flying again, power on or off. The high-aspect-ratio, clean composite wing delivers excellent cruise performance. Yet a new wing-tip design deliberately invokes drag when it’s most needed: during the landing phase.
The full-span flaperons, when deployed, interact with the wing tips to create additional drag. This allowed Alpha’s designers to eliminate the added weight and complexity of dive brakes, a staple of the Virus and its sister ship Sinus. By setting up a stronger vortex at the tips, glide angle is sufficiently degraded. An added benefit: students don’t have to learn dive-brake use during training.
Good glide control is still required to avoid undue drama in the landing phase: Alpha is a slippery bird even with those flaps-down, draggy tips. The optimal landing routine includes slowing below 70 knots abeam midfield, pulling on one notch of flaps (15 degrees), then slowing to 50 knots for the second, final flap setting (25 degrees).
I made three landings, including two where we came in deliberately high to confirm that, in the absence of speed brakes, a strong slip helps sufficiently to degrade glide angle without building unwanted speed. No, it’s not like throwing out a barn door as in a Cessna 172. That low-profile tail boom pulls substantially less drag than boxier airframes. But slipping is effective. I saw sink rates near 800 with no flaps and near 1,200 fpm with full flaps.
Touchdown was a breeze: I kicked her straight a few feet above that minuscule Brennand strip, countered the slight crosswind with lowered wing and a bit of rudder, then at under 50 knots, tugged an easy flare and set the bird comfortably down.
Roll response is a bit “dopier”—more sluggish—at 50 knots as expected, but effective rudder management helps maintain alignment right through the flare. Alpha really is easy to land…but keep that speed below 50 or expect a long float and possible go around.
I consider the Pipistrel Alpha Trainer to be a real breakthrough. Implemented at flight schools in sufficient numbers, it could become the Piper Cub for an entire generation of new pilots who will learn the importance of deft three-axis control and energy management…and have lots of fun in the process. The Alpha is a major step forward, and lest we forget, at a price that few LSA with conventional construction have been able to achieve. That alone should rightfully deliver it to training ramps across the country…and private hangars, too. Well done again, Pipistrel!
The Importance of Aspect Ratio
|Ever notice the difference between the wing of an albatross and a hawk? Although both are soaring birds, the albatross’s wing is more efficient, because the ratio of its long span to the narrow chord bestows a higher-lift/lower-drag efficiency that the hawk will never achieve.
In nature, birds like the albatross that fly long distances have high-aspect wings, which minimize fatigue (lower fuel burn). Hawks, by contrast, benefit from low-aspect-ratio wings that give them better maneuverability on the hunt.
Aircraft designers invoke “high-aspect” wings such as in the Pipistrel line of aircraft, for applications where high efficiency is considered primary in importance, such as optimizing weight and fuel economy without sacrificing performance.
Consider two airplanes: the Piper Cub and the Pipistrel Alpha Trainer. The Cub has an aspect ratio of 6.9, while the Alpha sports 11.8. The Cub wing looks noticeably less “narrow” than the Alpha’s. Predictably, the Cub wing produces less lift and more drag per square foot than the Alpha wing.
Not all airplanes need or want a high-aspect wing. Also, they can be more challenging to design: longer, narrower spans benefit from composite technologies that makes high-strength/low-weight, cantilevered (no struts) designs possible.
Remember the early biplanes, with two “stubby,” strut and wire-braced, low-aspect wings? That was necessary in part because aerodynamicists, although they recognized the benefits of clean, streamlined structures and high-aspect-ratio wings, didn’t have the materials and construction skills back then to build them.