FL08 - Ultralight anphibian aircraft

febbraio 10, 2016 | By Lenci Design S.r.l. | Transportation | Aviation and Aerospace

It is based on the best safety use for non-professional sport pilots


FL08 - Ultralight anphibian aircraft

Lenci ModelsS.a.s. was born as a spin-off of Lenci Design S.r.l. of Fabio, Maela and JunaLenci. This company has a forty years old experience in the field of industrial design, with over 700 products that broaden from everyday home design items, to yachting industry. For this reason R&D in the laboratory is the focal point for Fabio Lenci, in fact making prototypes is the most challenging experience for a company that puts innovation as a central goal. After the great experience in the yachting industry, he started working with high level aeronautical models, and this was the starting point for his most challenging project, build his own lightweight amphibious aircraft that combines performance, design and safety. Fabio Lenci, designer, LSA pilot and formerly a military pilot, manager of the workmanship, to start this challenge is availing himself of the collaboration by professors of Sapienza-University of Rome and other engineers and aeronautical experts. FL08 is an amphibian aircraft designed to fit into the new category of "Light sport Aircraft-LSA”. The prototype in fiberglass/Kevlar/carbon fiber with epoxy composite matrix is developed in LENCI MODELS laboratory in Rome. The design philosophy is based on the best safety use for non-professional sport pilots as well as an attractive design: “being safe doesn’t mean being ugly”. The aircraft is the result of a research applied between innovation and market investigation made among LSA pilots as potential LSA purchasers. Safety is very important for us, for this reason FL08 is configured with a double engine solution: the main engine for cruising and the second one as auxiliary or emergency engine. They can work simultaneously even in case of partial failure of the main engine, thanks to two flywheels acting on a single variable-pitch propeller. In case of complete failure of the two engines (rare), an emergency parachute anchored at the CG point carries the aircraft on ground with non-destructive glide speed and angle. Anti-explosion fuel tanks are placed into the trailing edges of the wings, isolated from the engine compartment. Seats are fitted with shock absorbers and is also equipped with airbags placed in front of the seats. LCD 10” GPS 3D instruments and artificial horizon make navigation easy and monitor data from engines and systems, activating light and acoustic signals in case of anomalies, advising of possible flying errors such as water landing with landing gear extended or normal landing with landing gear retracted. A video camera with recording functions is placed in the upper part of the tail fin, records all images (in every light condition) also giving a sight of the propeller and all parts that are not visible by the pilot under control. An accurate aerodynamic study of the wing tips is being made to avoid aileron stall and to reduce induced drag, moreover the solution of installing blown flaps reduce stall speed so to fit into the LSA category. As far as concerns everyday maintenance the aircraft can be disassembled by two people, unplug wings and tail permitting easy storage in a car garage and transport on road and the landing gear can be removed in just one hour. Dismounted it has a width of 2 meters (6,6 ft). For future serial production and commercialization, the project includes the possibility of various operative solutions, for example it can be built in ground configuration excluding features of other versions such as the amphibian. Motorization can be chosen too, according to limitations imposed by weight, structural stresses and center of gravity. Paintings and decorations are on demand. After testing RC models, a 3D-CAD model was built to proceed with the structural analysis (FEM with Nastran/Patran software) to see the critical points of the structure in the flight envelop of the aircraft To build an advanced prototype the best choice was to use composites. The 90% of the aircraft is in a sandwich of epoxy/fiberglass and foam, while each part of the wing is an unibody sandwich epoxy/carbon fiber and foam piece, while the fuel tanks are in aluminum reinforced with fiberglass and Kevlar. This was entirely made in the LENCI MODELS laboratory reaching a great result in terms of technology, precisions with respect of the FEM results. The double engine configuration is mounted on a modular alloy bay built to hold with little changes different motorization. After an accurate research Simonini Victor 1 and Victor 2 where mounted on the prototype. The advantages of using these engines are the lightweight, low fuel consumption and as the aim of Fabio Lenci was to build a real “Made in Italy” product, they come from Modena, the land of Ferrari, Lamborghini, Ducati, Aprilia, Pagani and some more small companies that produce high quality automotive products, Simonini is one of these. As said before the holding bay of the engines is modular and could be easily modified to hold another engine as a Rotax 912S as main engine or change the emergency one with an electrical engine. The capability to change engine configuration is due to the accurate design of the engine bay, that with its flexibility allows an easy and rapid centering of the airplane without affecting the longitudinal stability. The propeller is a 3-Blade full carbon one produced by Warp Drive with a 172 cm of diameter. The hub is a variable pitch full carbon one produced by Porcelli, with the capability of a reverse to give a better control of the airplane once laded in water. Design and safety are the leitmotiv of this product, the cockpit is done to host front airbags, and to well contain the body, giving a sensation of safety and comfort. The central cloche is very comfortable and allows the pilot to hold maps on his laps, moreover with his shape gives the chance to lead it from the left or right seat. There is also a small luggage rack that can contain two personalized backpack with the embroidery of FL08 and a personalized with the name of the pilot and/or the name of the aircraft . The first flight test was done in Celano at an elevation of 2230 ft (830 m), controlled by the instructor pilot Sergio Pizzichini. For landings the maximum length registered was of 200 m. Take off and landings are very easy because the prototype is well balanced end easy to be controlled: for example during the second day test the pilot landed successfully in a control free configuration. The pilot expressed full satisfaction about the flight sensations onboard the FL08 and his capability of flying stable in a control free configuration, however he asked to make little improvements for the ergonomic of the pedals and he gave some tips to improve the sensibility of the roll control. We are studying a complete line on FL08 base, a full terrestrial version and a “super marine” one (maybe with ekranoplan features). Anyway there is a big interest also to equip the FL08 in the near future with an emergency 40kW brushless electrical engine and LiPo batteries. On the winglets will be mounted high power led lights to help landings, take off and taxing procedures with low visibility. As far as concerns the wing itself is planned to be equipped with vortex generators to increment lift at high attack angles. Instruments are analogical en digital, while for flight navigation is used an iPad. Anyway is possible to equip it with a Garmin flight deck.

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