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Jet Shark
Jet Shark
© Gryf design

When 300km/hour is not enough, there are some ideas to create jet-powered aircraft using Shark design, so You could fly 400-500 km/hour according to used engine.

Price-induction jet looks nice for that purposes : 
At Take Off Power, you can get up to 255daN, consuming 80kg/h of fuel for the DGEN 380 and 330daN with 100kg/h fuel consumption for the DGEN 390.

www.price-induction.com

of course - this kind of aircraft cannot be called Ultralight, although its empty weight could be  very similar

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Weather
Skyboy flashback Print E-mail
Written by Dan Johnson   
Sunday, 05 August 2001 00:00


Mike Makepeace taxies out in the Skyboy Super at Sun'n Fun. Designed and built in the Czech Republic, the aircraft has a rather unconventional profile, but very predictable handling qualities, says Dan Johnson.
USAThey do it differently "over there." In the United States designers are frequently individuals with small businesses and few employees. That's not so in Eastern Europe where the shift away from Soviet communism is still very much underway. High-paying jobs are nonexistent. People are happy to work for less pay per month than American workers get per week.

Designed by a Team

Keeping that fact in mind, you won't be surprised to hear a team of no less than 16 designers from the LET Kunovice aircraft factory created the Skyboy and the Griffon, among several other derivative designs. LET's large technical staff works under the direction of aeronautical engineer Jaroslav Dostal, who is in charge of preliminary design.

LET Kunovice designs and builds commuter aircraft such as the 19-passenger L-410 and the 40-passenger L-610 and world-class sailplanes such as the L-23 Super Blanik and the L-33 Solo. Many of these high-quality aircraft are flying all over the world.

In defense of the smaller American designers, here in the United States we have an abundance of service industries to build subassemblies. We also have computers and computer-aided design (CAD) software that drives CNC machines. Yankee designers don't need a team of 16 and would likely consider it a headache to manage so many.

In the Czech Republic, engineers handle most of the work themselves, and factories accomplish most tasks with hand labor, as they are rich in human resources. High-tech machinery is coming to these countries, but the process is slow.

The old country ex-communist ways may be different, but they are able to turn out great flying aircraft for the lightplane community. I've flown at least six aircraft built in eastern European countries and have thoroughly enjoyed all of them. The Skyboy is an excellent example, and it arrived here ahead of the others. How did that happen?

The Czech Republic factory is owned by Detroit, Michigan, resident, Ralph Mandarino. After selling his successful automotive business and finding himself restricted by a non-compete agreement, he decided to enter aviation. Mandarino saw a way to use his experience as well as his old-country family connections. He bought the design of the Skyboy as well as the manufacturing plant. Mandarino also hired Dostal full time, making Interplane a design force to be reckoned with in the light aviation industry.

Interplane's manufacturing facility is based in Zbraslavice, Czech Republic, just outside of Prague. Interplane is reportedly well equipped with modern machinery, thanks to American money. In addition to building the Skyboy, Interplane uses its special machining capabilities to seek new business in small metal assemblies and composites.

However, while showing an interest in imported designs, American pilots don't buy many foreign-built sport planes. A key reason that holds back U.S. purchases of imported aircraft has to do with local support. So, Mandarino set up Interplane USA as the American marketing arm and hired ultralight instructor and enthusiast Ben Dawson to be chief of operations. Dawson has been involved in the ultralight and lightplane game a long time. He's well known to many, which will reassure buyers of the Skyboy.

Fly and Buy

Dawson offers a ready-to-fly version of the Skyboy ultralight trainer. Buyers can take away a shrink-wrapped Skyboy that can be flown only a short time after the delivery truck leaves.


At first glance, the angle of the seats in the Skyboy looks unusual.
But after sitting in the aircraft a few moments, the semi-reclining position proves to be very comfortable. Johnson described it as "sitting in a La-Z-Boy chair, but better since this one flies."
At first glance, the angle of the seats in the Skyboy looks unusual. But after sitting in the aircraft a few moments, the semi-reclining position proves to be very comfortable. Johnson described it as "sitting in a La-Z-Boy chair, but better since this one flies."

While American builders could also offer a trainer fully built (assuming it met the definitions of Part 103's exemption), most produce kits as a way to keep the price lower. While the eastern builders can and do offer kits, their large low-cost labor pool allows them to use these workers to completely assemble planes. Doing that in the United States simply isn't cost-effective.

The Skyboy isn't, however, what you'd call "cheap." At about $20,000 it may be a decent bargain in a ready-to-fly machine. Less costly choices are available, but few will be as well equipped. And a fully built Skyboy at $20,000 compares well to some $15,000 kits, if you value your building time.

For the $19,900 list price you get an ASI (air speed indicator), an altimeter, a tachometer, a water temperature gauge, and a fuel gauge as standard equipment. Also standard are dual control sticks that are connected along the center consoles so that you have a side stick rather than one between your legs, which enhances freedom of movement. In-flight adjustable trim is also standard.

Skyboy seats come with 1-1/2-inch cushions, top and bottom, and bucket shells, but it is the cabin design that really adds comfort. The cabin floor is angled in such a way that your legs are supported from knee to foot. Rotax 582 power, four-point seat belt systems, plus a locking fuel cap for the 10-gallon tank round out the base features of this Czech design.

In case of a crash, the Skyboy has a sturdy fiberglass enclosure and a large diameter tubing support for the fuselage. A large diameter boom runs from the tail to the nose, within a few inches of the rudder pedals. "One of the key features of this airplane is how strong it is," bragged Dawson.


According to Dawson, the only creature comfort missing from the Skyboy Super's fully decked out panel was a CD player but we've figured out how to work that in, too, " he added.
The strength is a benefit for the purpose of flight instruction. Dawson said, "Skyboy is designed for a very harsh training environment. We have a very strong I-beam (lower fuselage) construction attached to the fuselage root or boom tube." Most of the airframe is bonded with solid aluminum aircraft rivets. Much different than blind rivets, this construction technique should make for a more durable aircraft.

Dawson continued listing design features, "In addition, the landing gear is a trailing link design made from very thick aluminum with motorcycle-type shock absorbers in between the landing gear and the I-beam. Large 14-inch tires help with off-pavement landings and are superior to the small 6-inch tires that are standard equipment on so many of our aircraft." He concluded, "This is all designed to help with training, to make landings easier and softer."

The N-numbered Skyboy also sported a full fiberglass enclosure (as opposed to the fabric rear portion of the Skyboy UL), and it had the fully faired wheelpants of our test plane. Since it no longer must make the exemption weight of 496 pounds, other accessories can be added to include the 80-hp Rotax 912 engine.

For those destined to go all the way, the Skyboy Super was just introduced at Sun'n Fun 2001. Using the 100-hp Rotax 912S, "The Super has every conceivable option possible to fit into the Skyboy," boasted Dawson. "Some people want everything but the kitchen sink, and this is it."

Function Isn't Everything

Dostal and his team of 16 aren't totally focused on functionality; they also care about appearances. For example, the tail was given a little more area in front of the vertical stabilizer so it would conform better to the sweeping lines of the tail and the aircraft in general.

Having recently attended another German air show, I was able to examine what Euroland calls an "ultralight." To great extent it isn't what Americans think of when they say "ultralight." The Skyboy is one to help focus our eyes on a continuing trend, that of divergence from the "original ultralights."

The first ultralights were typified by open cockpits, of which by far the most famous is the Quicksilver series. To this day, Americans buy plenty of these machines, which include trikes, powered parachutes, paragliders, and numerous partially faired designs.

The Skyboy is a fully enclosed model relying on smooth fiberglass work and standard aluminum aircraft construction in the airframe. However, the Skyboy will find favor with many students who aren't sure about the openness in many American ultralights.

Getting in the wide-door-equipped Skyboy is simple, and you are aided by gas pistons that hold the door open while you enter. The basic Skyboy trainer will come without doors, though cold climates may want to add them and subtract some other feature of equivalent weight. I didn't fly without doors.

When you sit back in the seats, you'll note immediately how comfortable the Skyboy cabin is. The seats are plenty wide for larger Americans, and thick cushions pad your back and bottom. But the feature that stands out in my mind is the floor. It's shaped to offer good leg support. It's like sitting in a La-Z-Boy chair, but better since this one flies. Because of the design, nearly your entire body from shoulders to calves is fully supported, meaning greater overall comfort and less chance of numbness on longer flights.

Dostal and his team also considered inside appearances when designing the Skyboy. Finishing the cabin with interior panels gives it a refined appearance, and this is standard equipment in the fully built Skyboy. I found the reach to the instrument panel a bit far for my arms; I couldn't touch it with the four-point shoulder harness securely fastened. Trim is also a bit distant for smaller pilots. A control such as trim that needs fine adjustment is more convenient when it is closer. A fuel shut-off valve is just above and between the two occupants, and a primer is just above the pilot's head, slightly to the right. A choke lever is on the top of the forward support tube. Though you'll need to remember which control is which, they are certainly easy to grasp.

For some reason, Interplane only provided toe brakes on the left side of our test plane. Though I experienced the hydraulic brakes, mechanical brakes are standard. Interplane deliberately left off the right side brake pedals in an effort to save a few pounds, though you can add dual pedals for $100 if weight is not an issue.

Because you cannot see upward well, I did my usual full circle, searching for traffic. However, as soon as the Rotax 582 pushed us into the air, the visibility became quite panoramic.

The Skyboy seemed to descend rather quickly, but because I prefer high approaches, a steeper angle was no problem. With no flaps, I turned to slips. I did them with the nose skewed to the right, though that was opposite the crosswind, because doing so used more right rudder. Dawson told me to keep the power on well into the approach. So, of course, I did at first. Later I made idle thrust approaches with no difficulty. The Skyboy exhibited very strong ground-effect performance. In three landings, I experienced smooth and gentle touchdowns. The bumps of a turf runway revealed the absorption capacity of the landing gear, leading me to agree with Dawson's conviction that the Skyboy is stoutly designed.

Cockpit Controls

The Skyboy isn't the first aircraft to use a shared joystick. (Canada's Merlin had the first I experienced several years ago.) Also, like the Earthstar Odyssey, each occupant has a place for his or her hand on a Y-shaped cabin control stick. The Y-shaped stick is very satisfactory for training or general use.

The Skyboy has positive aileron control linkage thanks to all-pushrod linkages to the root junction. I found no sensation of looseness in the controls; all movements felt like they had an immediate effect, which allowed for finer adjustment than more flexible control systems. Although the test Skyboy ran out of left aileron range in some situations, I was able to perform very successful Dutch rolls, showing adequate aileron authority in that speed range.

I enjoyed the light stick response combined with the modest roll rates, a great combination for a trainer. Dawson had said this characteristic was purposely designed into the aircraft and that it once had faster roll rates with somewhat higher stick pressures.

Despite its flowing lines, the Skyboy is a genuine ultralight/microlight. It can cruise into the mid-80s, but it commonly flew in the 60s. Climb was strong, at 800 fpm according to the factory. Since the Skyboy is barely within Part 103's exemption weight, its greater mass demands a more powerful engine to keep it going. The Skyboy comes standard with the Rotax 582 because Dawson feels the 503 in the training environment is "under too much stress, whereas the 582's extra power allows lower stress operation, which may make its maintenance requirements less in the long haul." In my reviews of stability, I found stalls in the Skyboy got very close to 30 mph according to the installed ASI, shortly after which point the gauge would drop to zero. Stall characteristics were very mild. Under full power, the Skyboy showed only a slight break that was not at all threatening. In power-off stalls, the Skyboy exhibited a clear break, though it was straightforward and easily controlled.

Check for Czech?

Our test Skyboy was equipped with doors, an electric start, wheelpants, gear fairings, and hydraulic disk brakes. According to Ben Dawson, none of those accessories could be used if you want your Skyboy to qualify under the exemption to Part 103. Interplane has set a target of 490 pounds (6 pounds under the maximum) to allow for slight variations in material. You can add whatever the engine will carry on the EX or Super models. Besides an N number, these models will also demand more cash.

The EX model starts at $14,900 for a kit without an engine. I didn't get a look at a kit manual. This is a new company, so it's hard to get builder reports, but Interplane claims build time is around 400 hours.

The Skyboy UL trainer model uses a fabric aft cabin enclosure as part of the effort to stay within Part 103 weights. The EX model can use fiberglass in this part of the enclosure, which looks a little sleeker. Interplane's Czech factory fully builds Skyboy ULs and test-flies them. For shipment to the United States, Dawson says, "They then dismount the wings and remove the struts and prop. They fold up the tail along the vertical, then wrap the entire plane in plastic wrap, and ship it to me." Customers will also receive a shrink-wrapped airplane unless Interplane USA processes the U.S. entry.

The Skyboy flew very nicely, and given its good trainer qualities and excellent cabin comforts, I believe this machine may develop a market in America. If Dawson and Interplane USA can maintain a high level of customer support, I think you can expect to see more Skyboy aircraft at a field near you.

SPECIFICATIONS

Interplane Skyboy UL (1)
Empty weight 490 pounds
Gross weight 1,000 pounds
Wingspan 34 feet (1)
Length 20.8 feet
Height 7 feet
Wing area 164 square feet
Wing loading 6.1 pounds/square foot
Standard engine Rotax 582
Power 66 hp at 6,500 rpm
Power loading 15.2 pounds/hp
Cruise speed 65 mph
Never exceed speed 70 mph
Rate of climb at gross 700 fpm
Takeoff distance at gross 250 feet
Landing distance at gross 150 feet

(1) The trainer has a larger wing because of European microlight rules (N-numbered EX version has 145 square feet of wing and a 30.5-foot span). Model as flown meets the requirements of a Part 103 exemption aircraft.