LSA seaplanes are a segment all to themselves. [See Breaking News at bottom!]
It isn’t only that seaplanes can offer “triphibian” capabilities (a term once promoted by MVP) because they can operate from land, water, or snow. That makes them versatile but amphibious craft must incorporate retractable gear and since they require a sturdy hydrodynamic boat hull as well as aerodynamic aircraft structures, the engineering task becomes significantly larger than land plane designs.
Icon took years with their A5 and Vickers is still working on their Wave. Both took more than a decade to reach market. Several other LSA seaplane projects required similarly lengthy development.
Now from Svenska Flygfabriken (Swedish Aviation Factory) comes LN-3. This new entry is distinctive because it is a tandem-seating seaplane. Yes, I know lots of Cub-types on floats are tandem but among boat-hulled seaplanes, I’m not aware of any others like this.
Why would this be useful? I can think of several reasons but one is that you can simply paddle your way to shore; the pilot can access both sides. No bow thrusters are needed; weight is saved.
Swedish Seaplane Project
“My father, Lage, my brother, Tomas, and myself founded a Swedish company in 2005,” wrote Staffan Norberg. “We started working full-time to develop and build LN-3 Seagull that year.” Yet that’s not when the project actually began.
Staffan explained, “It was a matured design already then. Lage had made the first drawings for the airplane in 1983.”
“In 2007 we displayed the airplane with a rollout in the local concert hall, Tonhallen in Sundsvall,” he continued. “We flew for the first time in 2008.” He observed that they are still flying that same aircraft and the team believes they have this well sorted out and are ready for market.
In an earlier iteration, Seagull used a strutted wing with titanium landing gear powered by a Jabiru 2200 engine that output 81 horsepower. “Since then the design has evolved,” Staffan said, “and today LN-3 Seagull has a cantilevered wing that is easily removed.” Carbon fiber is used in most of the construction including the landing gear. The engine selections now feature Rotax or D-Motor.
“We made a lot of modifications and have flown with three different engines,” related Staffan. “Early in the process we replaced the strutted wing with a cantilever wing to offer easy mounting and dismounting of the wings. We made a trailer for ease of moving the airplane to and from the airfield.”
Power has increased from the four cylinder Jabiru. “We have flown with the Rotax 914 Turbo plus a four-cylinder D-motor. We are currently using the six-cylinder D-motor engine.”
“All modifications were made to the original aircraft… [but we have now] finalized the design of the production airplane in 3D-CAD environment,” Staffan clarified. We have made most of the molds (image) and will start producing kit airplanes in summer 2024. This start of production is a great milestone for us and, of course, is very exciting!”
After many flying hours have been logged, Staffan is clearly ready to get LN-3 Seagull on the market. “It’s a nice flying airplane with very good performance and a totally unobstructed, hard-to-beat view from the cockpit,” boasted Staffan.
Describing LN-3 Seagull
LN-3 Seagull is a high-wing amphibian with two seats in tandem and the engine in a pusher configuration on top of the aft portion of the cabin compartment.
Characteristic features are the high aspect ratio wing and the retractable main landing gear location in a wing shaped pod constructed at the lower part of the fuselage. This pod is completely above the water surface when the LN-3 is floating so the wheels and the foam filled wheel pants can serve as stabilizing floats. Drooping wing tips provide additional stabilization during water handling under severe conditions.
The airplane is equipped with conventional ailerons controlled with the stick via push-pull rods. The flap is of slotted type with a maximum extension of 45 degrees. A horizontal stabilizer and the elevator are controlled with the stick via push-pull rods. The rudder is controlled with pedals via cables and it extends to become a water rudder controlled with the pedals. Hinges on all control surfaces are of ball bearing type and the elevator is fully balanced.
LN-3 Seagull landing gear is composed of retractable main gear and a steerable tail wheel. The main gear legs are built of carbon fiber and euipped with a oleomatic spring/damper. Retractable gear are actuated mechanically with a lever in the cockpit.
The fuselage consists of a hull built from aramid fibre and the rest of the fuselage is carbon fiber. Fuselage panels are of sandwich construction and behind the aft seat a main bulkhead with a metal truss distribute the loads from the fuselage to the wings. The cockpit floor is constructed to permit the hull to flex somewhat when landing on water.
LN-3’s structure is robust as the manufacturer said, “The design is made in compliance with FAR 23 aerobatic category thus making the LN-3 permitted for aerobatic flying.”
The fuel tank is placed in the fuselage and the filler neck is positioned under a lid on the left side. “This is an advantage compared to having wing tanks, especially when taxiing on water,” noted Staffan. “The engine will have good fuel supply without the pilot having to monitor which tank is chosen.”
“We have now opened our order book for LN-3 Seagull kits” said Staffan with clear excitement. “We are also looking for partners to present and sell the airplane outside of Sweden.”
How Much? — The company advised, “LN-3 Seagull kit normal price is $88,000 and includes everything except engine system, avionics, propeller system, electrical system and paint.” They are offering a discount on the first orders; if you want the deal, send Staffan an email.
TECHNICAL SPECIFICATIONS:
LN-3 Seagull
All information provided by the producer
Useful load & payload calculated independently
- Maximum Takeoff Weight — 1,320 pounds* (600 kilograms)
- Empty Weight — 705-772 pounds (320-350 kilograms)**
- Fuel Capacity — 29 US gallons (110 liters)
- Max Fuel Weight — 176 pounds (80 kilograms)
- Useful Load at 1,320 pounds* (600 kilograms) — 615-548 pounds (279-248 kilograms)
- Payload (at full fuel) — 441-374 pounds* (200-169 kilograms)
- Load Factors (at 1,320 pounds / 600 kilograms) — +5.4, –2.7 G
- Wing Span — 35 feet 7 inches (10,830 millimeters)
- Fuselage Length — 22 feet 1 inches (6,720 millimeters)
- Fuselage Maximum Width — 30 inches (760 millimeters)
- Fuselage Height (fuselage horizontal) — 7 feet 1 inch (2,150 millimeters)
- Maximum Horizontal Speed at 1,190 pounds / 540 kilograms at sea level — 120 knots (222 kilometers per hour)
- Powerplant — D-motor LF26/LF39, Rotax 912/914
- Cruise Speed at 65% power — 95-110 knots** (176-204 kilometers per hour)
- Stall Speed, clean— 43 knots (80 kilometers per hour)
- Stall Speed at 1,080 pounds / 495 kilograms, best flaps and gear — 35 knots (65 kilometers per hour)
- Maximum Climb Rate — 1,180 feet per minute (6 meters per second)
- Maximum Maneuvering Speed — 115 knots (213 kilometers per hour)
- Never Exceed Speed — 152 knots (282 kilometers per hour)
- Endurance cruise speed 65% 6,1 hours without reserve
- Range at Cruise Speed, 65% power — 580 nautical miles (1,070 kilometers)
- Fuel Consumption — 26 miles per gallon (9 liters per 100 kilometers)
* approval category dependent — European designs may have a lower gross weight
** engine dependent
This company video shows takeoff from land, gear retract, landing on water, and paddling to shore.
Late-Breaking NEWS
in the LSA Seaplane Sector
Unrelated to the LN-3 Seagull story…
As this article was going online, Icon Aircraft announced the company was entering Chapter 11 bankruptcy protection, “The Company further disclosed that it intends to pursue a sale of its business,” said the release.
“We plan to continue to produce and sell aircraft and provide first-rate service, training, and support to our customers,” stated Jerry Meyer, CEO of Icon.
After recent difficult news for Searey producer Progressive Aerodyne and Seamax from Brazil, this may illustrate the challenge of bringing a LSA seaplane to market.
Aero Adventure makes one- and two-seat seaplanes in kit or SLSA ready-to-fly form. image by Philip Terpstra
Producers of more fundamental seaplanes like Aero Adventure may shine a light on the value of simpler, more affordable projects. Aero Adventure will appear at Sun ‘n Fun and offers highly affordable aircraft.
Another Brazilian producer, Scoda Aeronautica, is enjoying good sales and success with their Super Petrel XP (recent article), which will debut at Sun ‘n Fun 2024.
The excitement in Lakeland, Florida is about to start. Check out all the latest and greatest at Sun ‘n Fun’s 50th Anniversary celebration.
Beautiful Seaplane, very easy tu fly. I flexion it. It was a very Nice expérience.