Alert: This article is dated and some links may no longer lead to the desired destination. —DJ 0121 Maybe you’ve heard: “You can’t build a three axis airplane that can safely remain under the 254-pound weight limit.” Some allege: “You can’t buy a three axis Part 103 ultralight that actually meets the rule.” I’ve said this many times… WRONG! You have a few choices for Part 103 airplanes that perform well and they aren’t all trikes or powered parachutes (though several qualifying candidates do come from these segments). I’ll soon post fresh articles on the Kolb FireFly and Phantom X-1. Each can meet Part 103. Now, we have what may be the first all-new Part 103 ultralight in many years. ZJ Viera was designed in Europe by Marek Ivanov, CEO of Interplane Aircraft (photo). At Sebring 2008, plenty of attendees spent time examining the two examples present; one was the original monowheel (which I tend to prefer) and a tri-gear variation.
Email: Interplane@cmail.czZbraslavice, -- - Czech Republic
Fantasy Air USA and LSA America in central North Carolina sell three SLSA: Interplane SkyBoy, Fantasy Air Allegro 2007, and Flying Machines Mystique. They’ll soon also have the Part 103 ZJ Viera. *** In addition to distributing LSA nationally, Fantasy Air USA runs a profitable flight training operation. Proprietors Doug and Betty Hempstead report 33 students have completed training with an average of 28 hours to obtain their Sport Pilot certificate. Using the Allegro at $70/hour + $30 for a flight instructor, they’ve kept the cost below $3,000 — compared to $8,000 or more to get a Private license. Doug reports average burn of just 2.5 gph during instruction (training is flown slower than cruise speeds). Many students drive 1-4 hours to obtain training, though a map on the office wall shows a growing network of Allegros used in flight training.
In my work for the LSA industry since its birth in the summer of 2004, a common lament I’ve heard is that we have “too many…” new aircraft names, company names, importer names. These statements were from people actively working with the industry so newcomers are surely confused. *** Although I believed I had good information, for some time in SPLOG postings and in articles I’ve written, I’ve called Mystique an airplane from Interplane, the folks who build Skyboy and more (see photos). But Flying Machines, another Czech company, is Mystique’s creator. Thanks to Pascal Nelson of Greensboro NC for catching the error. Other websites I’ve visited also have it wrong, and while I’m curious how that happened, it’s now corrected everywhere on ByDanJohnson.com. *** Flying Machines was formed in 2004 and builds two versions of the FM250, the Vampire (for Europe) and Mystique (for U.S.).
You can hardly doubt the headline. A cruise through our SLSA List will show almost a quarter of all (12 of 50) designs that have won certification are from the Czech Republic. Even the USA counts only 11 SLSA models so far. Yet perhaps showing global cross-pollination, at least two Czech producers are owned by Americans (Czech Aircraft Works and Interplane). Even inside the Czech Republic one company often builds parts used by others. Since the Soviets withdrew 17 years ago, the Czech Republic has embraced recreational aviation with excellent success. *** Of course, Germany, Italy, France and Spain plus East European producers in Poland, Romania, and Hungary have also made their impact in the American LSA market. So, ASTM‘s LSA committee will hold its next standards writing and review session in Prague, Czech Republic. I’ll be going as will several other American leaders, partly as a significant gathering of EU aviation officials will also meet in conjunction with the ASTM meeting.
Way back in time, back before Light-Sport Aircraft…well, five or six years ago, Skyboy was one of the hot ultralight models. Prices were low, flight qualities were good, and cabin comfort was excellent. It also had a unique look. But after a fast start, Skyboy seemed to lose direction. Even a name change was attempted to reposition the design. Waves of new SLSA were stealing the show. *** Yet Skyboy is back! Interplane remains the manufacturer, but now Doug and Betty Hempstead of Fantasy Air USA and Allegro fame have picked up the Skyboy. And they got it SLSA approved, number 41 in the SLSA sweepstakes. The North Carolina company is establishing itself as a supplier of modestly-priced yet intriguing SLSA, the Allegro for sixty something, and now the Skyboy for a remarkably low $47,500. Lots of options can be added, but for well under $50K you get a fairly well equipped, ready-to-fly airplane.
Recognize that tail? You’ve seen it twice before on designs that earned Special Light-Sport Aircraft approval: Interplane’s Skyboy and FlyItalia’s Sport Rider. Designer Jaro Dostal’s signature is the shark fin vertical stabilizer. Skyboy is sold in the U.S. by LSA America. SportRider (MD-3 Rider in Europe) is not presently available in the USA. *** Now from the fertile mind of Dostal comes the Shark. It will be produced by Comp-Let, a producer of composite parts for many companies including Diamond, Aeropro, and FK Lightplanes. Jaro’s design bureau is leading the development effort. “SportShark will fit LSA rules with a larger wing, simpler flaps, fixed landing gear and prop,” declared Comp-Let. “We are finishing the aerodynamic design calculations (forces, structure, stability). Designers prepared a cockpit mockup. We have started to work on a fuselage model. The plan is to fly a prototype by spring 2008.
Easily one of the most fascinating airplanes to appear and show well as the airshows of 1999 was the east European-built Skyboy, sold in this country by Interplane. In truth it’s not only sold here by this outfit, Interplane is the name of the company building these aircraft in the Czech Republic. It may not be of American heritage but from what I could tell it quickened the heart of Yankee pilots. Under the direction of Jaroslav Dostal, a veteran of the LET Aircraft Company which builds 19- and 40-passenger commuters, a group of talented designers created several sport aircraft of which Skyboy is one. It’s abundantly clear these men knew their job as one examines the workmanship on the fully factory-built Skyboy being marketed to American ultralight trainers. Yet the shapely exterior is not the whole story. As you open the door of the Interplane Skyboy you see a nicely finished interior that invites your entrance.
|Empty weight||490 pounds|
|Gross weight||1,000 pounds|
|Wing area||164 square feet|
|Wing loading||6.1 pounds per square foot|
|Kit type||Fully Assembled2|
|Build time||300-400 hours|
|Notes:||1Trainer has larger wing due to European microlight rules (N-numbered EX version has 145 square feet of wing and a 30.5-foot span).|
2Kit manuals not examined.
|Standard engine||Rotax 582|
|Power||65 hp at 6,500 rpm|
|Power loading||15.2 pounds per horsepower|
|Cruise speed||75% power) 65 mph|
|Never exceed speed||70 mph|
|Rate of climb at gross||700 feet per minute|
|Takeoff distance at gross||250 feet|
|Landing distance at gross||150 feet|
|Standard Features||Rotax 582, ASI, altimeter, water temp, tachometer, and fuel gauge, mostly enclosed cabin with wide seating area, folding tail, quick-release pins in wing, in-flight trim, remote choke, convenient full shut-off, shock-absorbing gear, steerable nosewheel, mechanical brakes, dope-and-fabric wings and tail.|
|Options||Hydraulic brakes, engines up to 81-hp Rotax 912, electric starter, 4-blade prop, additional instruments, fully-assembled option, doors, and ballistic parachute in progress as of April 2000.|
|Construction||Aluminum airframe, fiberglass fairing, hydroformed aluminum wing ribs, dope-and-fabric wing coverings. Made in the Czech Republic by American-owned company; distributed by U.S.-owned company.|
Cosmetic appearance, structural integrity, achievement of design goals, effectiveness of aerodynamics, ergonomics.
Pros - To American pilots this is a new, never-seen-before design, but the team behind it are accomplished engineers for a large aircraft builder. Certainly the design is unique among U.S. creations while still having a sleek appearance. Configured for American consumption, even the factory is now owned by Interplane, a U.S. company. Intended for the trainer market in many ways (see other categories).
Cons - No matter its strengths, it's a foreign design that not everyone in America will want; may limit eventual resale though nothing is sure at this early point. Testing was assured but not verified by documents or photos. Can meet Part 103 exemption, but at a loss of some items pilots like.
Subsystems available to pilot such as: Flaps; Fuel sources; Electric start; In-air restart; Brakes; Engine controls; Navigations; Radio; (items covered may be optional).
Pros - Feature-laden design with in-flight trim, electric start (on test plane), hydraulic toe brakes, dual throttles and flight controls, remote primer, and cabin fuel valve. Easy engine repair access (especially while ultralight sits on tail). Clean refueling through outside fill point. Adequate room for radios. Several gauges are part of base equipment list.
Cons - Lots of features but no flaps which some consider essential for training aircraft (to assure broader experience). Electric starting may not allow plane to make exemption weight (depending on other optional choices). Brakes only installed on left side in evaluation Skyboy (such weight savings are needed to comply).
Instrumentation; Ergonomics of controls; Creature comforts; (items covered may be optional).
Pros - One of the most comfortable seating arrangements I've ever experienced; excellent leg support (the floor angles to fit your body). Y-stick control is quite workable (though not unique). Beautiful door system with gas pistons to aid entry and reduce likelihood of wind damage. Secure latches and large air vents also add value. Factory says cabin can be heated for cold weather use. With center stick, cabin seems roomier than those with dual center joysticks. Nicely finished interior.
Cons - It's hard to criticize this cabin. No easy seat adjustment was observed; differing cushions will work but may not always be available. Brakes on both sides seem important for a full-fledged trainer; you must save the weight somewhere else (if possible). No obvious cargo area, though some possibilities exist for creative builders.
Taxi visibility; Steering; Turn radius; Shock absorption; Stance/Stability; Braking.
Pros - Forward visibility is very good. Steering is enhanced by differential brakes (though these were only on the left side). Shock absorption is excellent; good range of movement in motorcycle-type hardware. Lateral stance is also very good. Ground clearance is generous; with stout gear off-field landings should not pose a big problem.
Cons - Upward visibility for pre-takeoff taxi checks is restricted by seating back into the cabin. No brake controls on right side. Nosewheel is lightly loaded, reducing steering effectiveness in some situations. Turn radius was not particularly tight.
Qualities; Efficiency; Ease; Comparative values.
Pros - Wonderful ground-effect performance with extended time for roundout and flare; excellent characteristic for students. Main gear is very absorbent, being designed for training. Excellent approach visibility over the low nose fairing. Slips were effective at controlling the approach path. Controls are authoritative enough to handle reasonable crosswinds.
Cons - Well out of ground effect, the Skyboy seemed to exhibit a higher sink rate (though this was not measured). No flaps will inhibit some training of students for these surfaces. Slips are effective but flaps are often a good alternate, especially for less experienced pilots. Soft left aileron and rudder restricted side slips somewhat.
Quality and quantity for: Coordination; Authority; Pressures; Response; and Coupling.
Pros - Y-stick proves very workable for the training environment (and adds cabin space versus center joysticks); instructor and student don't need to "hold hands" as on some models. For training, Skyboy handling was a good combination of lightness (less muscle needed) but moderate response (not sudden). Adverse yaw was modest. Good crosswind capability. Steep turns went well; plenty of pitch stick range.
Cons - Some right turn tendency was noted in test plane, requiring some opposing control. It was hard to clearly judge control harmony with this turn tendency (though this may have just been this one Skyboy). Rudder and vertical stabilizer appear somewhat small compared to comparably-sized ultralights.
Climb; Glide; Sink; Cruise/stall/max speeds; Endurance; Range; Maneuverability.
Pros - Strong performance on 65-hp Rotax 582 engine; factory reps say this choice offers more reserve than a Rotax 503 for training environment. Cruise ran beyond 80 mph according to installed ASI; "comfort range" appeared to be in the 60s. In ground effect, Skyboy retained energy surprisingly well (excellent for training).
Cons - Despite 65 hp, climb at gross is only listed at 800 fpm (though this is still plenty strong); an 81-horse option is available. Takeoff run (listed at 260 feet) felt a bit long. Endurance is limited to a couple hours; burn rate is 4-5 gallons per hour.
Stall recovery and characteristics; Dampening; Spiral stability; Adverse yaw qualities.
Pros - Stall was relatively slow, well down into the 30s. Power-on or -off stalls broke over but remained on course and were mild breaks. Slight forward sweep and dihedral contributes to stable flight characteristics. Cockpit was designed with crashworthiness in mind; main boom goes nearly as far forward as your feet and is braced with the forward support tube. Longitudinal stability checked out fine.
Cons - Stall had a definite break sometimes considered a good thing but which some instructors dislike. No parachute fitted yet, though Interplane is working with supplier to this end. Unable to verify structural testing (though design team appears very well-qualified to do job right).
Addresses the questions: "Will a buyer get what he/she expects to buy, and did the designer/builder achieve the chosen goal?"
Pros - Impressive group of engineers are behind this design which has been flying in Europe since 1992. U.S. ownership of the factory should help American buyers feel comfortable (owner has family contacts in Czech Republic). Design has been optimized to the training market both here and in Europe; task appears very well done. Ready-to-fly trainer may be appreciated by instructors who aren't keen on building. Well-equipped at base price.
Cons - No presentation of any kit manuals or literature; company seems focused on ready-to-fly aircraft (fine unless you want to N-number an accessory-laden Skyboy). Some equipment must be omitted to qualify for the training exemption, for example, the aft cabin is fabric and less sleek. Delivery time has no track record.
In May 2000 I wrote about the imported Sabre Aircraft Venture trike. That model from the Ukraine was quite impressive and worthy of your consideration. Now from the Czech Republic comes the Interplane Skyboy. Should Yankee ultralight manufacturers show concern? Yes, I’d say so. However, American pilots – while perhaps showing an interest in imported designs – don’t seem to buy a lot of these planes. Or do they? In recent years we’ve seen trike sales soar. Few industry leaders predicted this despite the persistent efforts of the big European trike builders. Many veterans claimed trikes would never have an impact on the majority of pilots who prefer 3-axis controls. They are being proved wrong, for now anyway. A key reason that holds back U.S. purchases of imported aircraft has to do with local support. Even a good importer can’t always control when spare parts are available. Interplane solves this dilemma in an interesting way and with American style: they bought the Czech Republic factory.