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?
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.
Is this available in the USA and what do they cost?
Dan Johnson says
Please feel free to use links in the article to contact SportairUSA to inquire about price and availability.
Shawn Rhatigan says
In the U.S., the FAA has specific requirements: The empty weight of the vehicle cannot weigh more than 254 pounds. It can only carry one person. It cannot have a top speed faster then 55 knots (63 mph). It can only carry 5 U.S. gallons of fuel. It must have a power off stall speed of 24 knots (28 mph) or less. The addition of floats and parachute give extra weight allowances.
You may not fly at night. You may not fly over groups of people. You may not fly over towns. You may not fly in controlled airspace, unless you meet more requirements. You may not fly in clouds or fog.
IF this vehicle does not meet ALL of these requirements, it is NOT a legal U.S. ultralight vehicle, and would have to be registered as an experimental aircraft, requiring an N number and a pilot license and medical.
This aircraft flies at 92 knots. The stall speed is not disclosed. The fuel tank size is not disclosed. There is mention of having a passenger, although it only has 1 seat.
Based on the speed alone, this is not an ultralight.
My assumption would be it stalls above 28 mph, which would also disqualify it.
The weight of this vehicle is not disclosed but meets the 286 pound restriction in Europe. We require 254 or less.
IF they get the weight under 254, change the prop to limit speed to 63 mph, and can get it to stall at or below 28 mph, THEN it is an ultralight. And under FAA rules, an ultralight is a ‘vehicle’, NOT an “aircraft”, so FAA rules would not apply.
Dan Johnson says
I find all your information correct but the designer assured me it is possible to make U.S. Part 103 and an American representative (Sportair USA) has agreed. On that basis, I will include it. If it ends up not meeting the 103 parameters as described in AC 103-7, then it will be removed from the list.
Come on Dan, you know better than thi$.
Dan Johnson says
I appreciate constructive criticism and have often learned from people giving me feedback, but I don’t know what you mean by this comment, Ken.
Lee Fischer says
The entire last paragraph is, in my opinion, completely out of the scope of FAR 103. Allowances are permitted up to the weight of the additions. I do not feel this paragraph is conducive to responsible “self regulating” behavior, also outlined in the advisory circular you quote.
Dan Johnson says
Hi Lee: I’m not sure what you find out of scope. The paragraph merely described what’s in the Advisory Circular, then attaching the entire document so everyone can see the original words. I imagine you mean the reference to “buying” more pounds, however, that is simply a statement of the situation. FAA will not ask field agents to tell a suspected non-103 aircraft to remove all elements of a parachute system (the airframe attachments for which can be critical and hard to remove) in order to weigh the aircraft without said parachute system. Instead, if a parachute system is installed, inspectors are guided to add 24 pounds to what’s allowed by regulation (making a total of 278 pounds). FAA field agents and very probably the aircraft operator are unlikely to know the precise system weight of a parachute system, which includes mounting hardware, attachment straps, a tigger housing and pull handle plus other elements. Assuming and allowing 24 pounds is a safer decision than demanding parachute system removal (so as to exactly weight only the airframe to assure compliance). Therefore, if a producer can install a parachute system that all-up weighs less than 24 pounds, a margin exists that might be allocated to, as an example, wheel brakes, or a fire extinguisher. A canister (hard-shell container) parachute system will weigh very close to 24 pounds, as FAA knows. A softpack system may weigh somewhat less, perhaps as much as six pounds less. However, if I missed further meaning in your comment, my regrets.
Andre Maertens says
My dream was to fly with Papy Boyington but now I will be able to pretend I do. Thanks for this design. I hope it is a popular one.