One-engine bizjet for 4-6 passengers, used parts , subassemblies and systems from L-39 Albatros military trainer. All metal low wing , which styling is purposely done in military look, connected with thousands flying L-39 Albatros military trainers. Cruise speed 500-600 km/hod.

All metal single engine Business Jet for 4 to 6 passengers

Aircraft is developed like cheap classic all-metal biz-jet with low expenses operation, to fill a gap between fast one-turboprops like TBM700 and small two engines biz-jets, like Cessna CitationJet. The goal is combination of biz-jet comfort and altitude with roomy cabin and small needs of landing strips and low price. Preliminary price 2 million $ would be lower connected with circa 3,2 million $ of CitationJet, or similar like around 2 million $ for turboprop TBM700.

TECHNIAL DESCRIPTION:

Classical aluminum alloy riveted design airframe single engine low wing with classical tail and circular cross section pressurized fuselage for 4 to 6 passengers. Position of air intakes with special designed undercarriage enables to use this aircraft for grass unpaved airstrips. Unswept wing with efficiency flaps and fuel tanks on wing tips, three-wheel landing gear, retracted into the wing and forward part of fuselage. Tail unit with swept vertical and unswept horizontal stabilizer and the one-piece elevator. The wing and rear part of fuselage are geometrically identical with the L 39 Albatros military trainer, with possible changes of vertical stabilizer, to eliminate bigger front part of fuselage, and with air intake, moved to the rear position. Circular cross-section pressurized front part of fuselage is all new design. Fuselage height 1550 mm enables 1450 mm cabin height in the aisle, cabin floor has 185 mm lowered aisle between seats. Divided portside crew/passenger door behind the cockpit with integral steps in its down part. In the middle part of fuselage there are two pairs of seats (vis-a-vis), with the folded tables and individual air conditioning. In the rear part of cabin there is situated closed compartment with right side baggage compartment and left side foldable seat with emergency toilet into, after closing usable like classic lavatory. Opposite to entry, there is the buffet, or alternative next seat, situated sideward in flight direction.

TECHNICAL DATA of L-539 aircraft

• Wing span 9,46 m
• Length overall 13,5 m (for L-39 12,13 m)
• Height overall 4,77 m
• Wing area 18,80 m2

WEIGHTS

• Empty weight 3600 kg
• Max T-O weight 5600 kg
• Fuel 1200 kg
• Payload 800 kg

PERFORMANCES

• Maximum speed 700 km/hod
• Economical speed 600 km/hod
• Range 2500 km
• Service ceiling 11000 m
• T-O run 970 m
• Landing run 800 m

POWER UNIT

21,57 kN Progress (Lotarev/ZVL) DV-2 turbofan or 18,15 kN Garrett TFE731-4

During last years dialogues about release of Regulations for small aircraft transport with one turboprop and turboshaft engine was begun in USA. Its better maintenance characteristics and higher reliability and lobbing of domestic manufacturer brought change of meaning ever FAA, or operators. On the bigger reliability of new jet and turbojet engines background FAA gave agreement with commercial IFR flights for one- engine turbine aircraft.

Although these dialogues were connected with turboprop airplanes, difference between prices of planes with turboprop and turboshaft engines brings to the market a new family of planes - one engine biz-jets, like all-composite VisionAire Corp Vantage, Williams International FJX-2, Century Aerospace Century Jet...

Because their weight, thrust, and all basic dimensions corresponds approximately to Czech jet trainer L-39 Albatros and in the same time there are thousands of cheap older Albatrosses from the Soviet Union for sale, the situation offers to us to prepare the new all metal biz-jet with really low development expenses. The idea to use some exist military plane for rebuilding to the biz-jet is not new, the first successful biz-jet, named Learjet aroused in the same style - from the prototype of FFA P-16 Düsenstorch fighter, developed for the Swiss army.

All metal design brings an other look opposite to its competitors, and using of finished parts and systems brings lower expenses for development , so lower risk. Expenses for building of first prototype would be true lower, preliminary 3 to 4 million USD – if we rebuild it from some used plane. After the finishing all needed documentation, preparing of the strength proofs, serial certification etc., expenses will be higher - hard preliminary ten million USD. By the perspective price of this aircraft 1,8 to 2 million USD, break even point would be ( by classical recalculation of development expenses circa 20%) 30-th piece of aircraft only ! Of course, there is hard preliminary estimation, but by adequate interest, we would offer all-metal planes with proofed 2/3 of design. We can use tested and proofed systems, only with changes connected with higher simplicity and their civil certification.

In the case of cheaper „proof of concept“ aircraft there would be possible to use rebuilt aircraft not only for concept proofing, but for the show plane and in the USA like an EXPERIMENTAL rebuild set, to offer it to customers and perspective collaboration as cheap and as quickly as possible.

If we want to save some next development time, we can use some front part of exist all metal biz-jet, for example Swearingen SJ-30 which is designed in the similar look like a L-39 from ing. Vlcek. The other variant for 4 to 5 passengers only, with the shorter middle part and doors between two pairs of seats, can have littlest problems with weighing and new needed parts.

So, development of this shorter version can be simpler and cheaper.

© Ing. Jaroslav Dostál, Head of preliminary Design LET 1999