Most ultralight aircraft (officially: "ultralight vehicles") are rather simple constructions. They must be to stay within the tight constraints of a 254-pound maximum empty weight.* That’s not a negative comment about them. Actually, it's the opposite. To build a flying airplane that weighs less than the engine alone on a Light-Sport Aircraft, a designer has to be unusually clever. All aircraft are constrained in weight by the laws of physics. Ultralights are further constrained by regulation. A key way to keep an aircraft light is to keep it simple. Indeed most 103 ultralights are quite basic. However, as years passed some engineers have found intriguing solutions. I recently wrote about the composite Swan. Why not one using extensive carbon fiber?

Carbon Corsair

German developer Jörg Hollmann took a different approach, one that consumed a few years of effort. He wanted an aircraft that resembled the famous World War II F4U Corsair fighter. One glance at the nearby photos or the two videos below tells you he did very well. Here's a bit of history about Corsair's inverted gull wing. "Corsair is a newly developed aircraft following the German LTF-L [very light aircraft] regulation," said Jörg. "As well [Corsair meets] many other national regulations, for example, the British SSDR, the Italian, French, Czech, Polish and even the U.S. FAR Part 103 regulation." For the latter Jörg said the empty weight, MTOW and speeds are slightly reduced." In countries where speed is not regulated, Corsair can hit 125 miles per hour. "The general layout — a low inverted gull wing — has been successfully used in several aircraft already," explained Jörg. "The Chance-Vought Corsair surely is one of the more famous aircraft with this concept." Jörg notes the main advantages to this configuration are a low interference drag between wing and fuselage as well as an ideal landing gear position, "which allows as well a nearly perfect angle for take off and landings." Corsair is adjustable to pilots of many sizes. "The ergonomics have been optimized with the help of our local flying club," Jörg recalled, "[so Corsair] is suitable for pilots ranging from 5 foot 4 inches to 6 foot 8 inches (1,60 to 2 meters). Cockpit width is 23.6 inches (60 centimeters). "Our seat is adjustable in four length/height positions and the incline is independently adjustable in 11 positions," he said (see in video). "Rudder pedals are adjustable as well and the stick has two positions." In other words a fairly wide range of pilots should fit in Corsair.

Growling Into the Air

In our original, longer video (below) you hear the sound of Corsair's engine with its distinctive low rumble. Some call it a "bark," others have said "growl." Jörg said, "We selected the Verner Scarlett 3 VW, a four-stroke, three-cylinder radial engine, [which was] purposefully designed as a light aircraft engine." The Vernor produces 42 horsepower at 2500 rpm using a displacement of 96 cubic inches (1.6 liters). "The high engine torque allows the use of a rather big and efficient propeller," observed Jörg, again mimicking design parameters of the F4U Corsair. "We use a ground adjustable 63-inch (1,60 meter) carbon prop that can produce, depending on the blade pitch, up to 220 pounds of static thrust, more than enough for Corsair's empty weight!" U.S. importer SportairUSA, well known for their representation of the Zlin Shock Outback and Shock Ultra, is scheduled to receive their first Corsair in September 2020 (though shipping and Customs inspections are less certain due to the virus). Corsair is not your low priced ultralight option, but with an all carbon fiber tube primary structure, I assume most readers are well aware this is a more costly production. SportairUSA may price Corsair in euros (€75,000) due to fluctuating currency at this time but the dollar equivalent is around $89,000 at today’s exchange rate. This is merely an estimate; please check with SportairUSA boss Bill Canino for details. If you like the idea of a lightweight, Part 103 aircraft (no license, no N-numbers, no medical) that is certain to turn a lot of heads at any airport you visit, Corsair is definitely a distinctive and interesting ultralight. * Empty weight of the basic airframe, without fuel, cannot be greater than 254 pounds (115.2 kilograms), however, FAA guidance (Advisory Circular 103-7) provided some exceptions. If you add an airframe parachute, FAA permits an extra 24 pounds. The lightest of such systems can weigh perhaps 18 pounds, so the designer can "buy" an extra 6 pounds. FAA doesn't encourage "cheating," but neither do they expect an owner to remove the parachute and all its elements so the aircraft can be weighed without it. Similarly, an allowance is permitted for flotation equipment — either twin floats or a single float with sponsons. Put all these elements on and an ultralight vehicle could weigh as much as 338 pounds empty. Here is the entire AC-103-7 document from January 30, 1984; it remains unchanged.

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https://youtu.be/k5EF-RU8qMs

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https://youtu.be/sFiwdv_ozJc

Two years ago at my favorite European airshow, Aero Friedrichshafen, Bill Canino of Sportair USA urged me to go look at a cool Part 103 project. With a general appearance resembling a Chance-Vought F4U Corsair military fighter, designer Jörg Hollmann's ultralight Corsair is reasonably authentic including its highly distinctive inverted gull wing design. Two years ago when I saw the bare bones example — exhibited for this small shop design and manufacturing organization in BP Oil's display stand — it was easy to get excited by the concept but less obvious to imagine how it might eventually look. At Aero 2018 the visual mystery was solved. Anyone who has admired F4U Corsair's angular wings will be drawn to ultralight Corsair. Even the engine mimics the original's Pratt & Whitney R-2800 Double Wasp, except at ultralight weights and power. Jörg chose a three-cylinder Verner radial to power his diminutive aircraft. The whole package was fascinating to those of us who enjoy single seat designs. The truly good news for Yankees who might want to own such a creation is that Sportair USA boss Bill has placed an initial order. For a tiny company, such a launch customer greatly increases the likelihood that this unqiue entry will makes it way into American skies. Of course, Europeans also recognize both the F4U resemblance and the coolness of this design effort. While fabric covered (also for lightness), Jörg refers to his internal carbon fiber tube structure as "a unique carbon-spaceframe technology." He added, "This property right-protected technology combines high strength with an unequaled low weight." Seeking a very low weight is partly a maneuver to steer clear of tough certification rules via the Part 103 / 120-Kilo Class / SSDR unregulations. A light design permits Jörg's design objectives. "Due to the light weight of the structure we were able to include all the ingredients for a high performance aircraft: outstanding aerodynamics, a strong engine with a big, efficient propeller, a short and aerodynamic landing gear, as well as effective flaperons." The carbon-spaceframe is effective, resulting in a calculated +9 and –6g ultimate load strength. "Furthermore," Jörg said, "the complete cockpit area is constructed as a Kevlar-reinforced safety cell." A ballistic parachute will further enhance safety. In our article from 2016 we unveiled Corsair in bare carbon fiber bones. That article also repeated Jörg's prediction that it would fly before Aero 2017. That didn't happen, however, Jörg said it is now ready for flight. "Corsair would have flown before Aero 2018 but a lack of ideal weather prevented that. We prefer calm winds and clear weather for a first flight in such a light aircraft," he explained. Because weather at Aero 2018 was warm and sunny, he hopes to get airborne in short order. Not only can Corsair meet USA's Part 103, it also can qualify for Germany's 120-kilo class and Britain's Single Seat DeRegulated (SSDR) class (article). Jörg explained, "Corsair currently fulfills the British SSDR regulation. An adapted version will comply to FAR Part 103." Although Corsair has ultralight proportions, it is versatile about pilots it can contain. "The ergonomics have been optimized with the help of our local flying club," indicated Jörg. "It is suitable for pilots ranging from 5 feet 4 inches to 6 feet 8 inches (1.60-2 meters)." The inner cockpit is 23.6 inches wide (60 cm). Corsair's seat is adjustable in four length/height positions. The seat back incline is independently adjustable in 11 positions. Rudder pedals are also adjustable and even the joystick offers two positions.

Corsair Specifications

Following are specifications of Corsair for both Part 103 and EU deliveries, as reported by JH Aircraft:

• Wing Span — 24.6 feet / 7.5 meters
• Wing Area — 108 square feet / 10 square meters
• Length — 20.7 feet / 6.3 meters
• Maximum Takeoff Weight (MTOW) — 551 pounds / 250 kg
• Empty Weight — 243 t0 265 pounds / 110 to 120 kilograms (depending on national regulation)
• Useful Load — 287 pounds / 130 kilograms
• Powerplant — Verner Scarlett 3 VW radial engine
• Power Output — 42 brake horsepower at 2500 rpm
• Cockpit Width — 23.6 inches / 60 centimeters
• Stall Speed — 24 knots (U.S.) / 55 kilometers per hour (EU)
• Cruise Speed — 54 knots (U.S.) / 168 km/hr (about 104 mph)
• Max Cruise Speed: 104 mph / 168 km/hr
• Maximum Speed — more than 124 mph / 200 km/hr
• Rate of Climb — 1,000 feet per minute / 4 meters per second

For more information, contact JH Aircraft or in the USA, go to Sportair USA.