Design and development
The L.66 was intended to be a low cost, easy maintenance two-seater. Thus a low power engine was required and the prototype was fitted with a 30 hp (22 kW) Haake flat twin, though other engines could be used. It was a cantilever parasol monoplane with an aerodynamically thick airfoil section wing, which had a simple, rectangular plan and significant dihedral. The wing was a wooden structure with two spars, the ailerons mounted directly to a rounded groove in the rear spar. It was linked to the upper fuselage by a rather complicated set of struts.
Traditionally, Albatros had constructed fuselages with wood frames but the L.66 marked a departure, with a welded steel tube longeron and strut framework covered with fabric. The sides were flat and almost airfoil shaped, with a blunt, rounded nose and taper aft. The nose mounted engine, driving a two blade propeller, was raised above the fuselage with a fairing behind it, enclosing the oil tank and with the instrument panel attached to its rear. The fuel tank was in the wing centre section, feeding the engine by gravity. Further aft, pilot and passenger sat side by side in the 1.2 m (3 ft 11 in) wide fuselage; tandem controls could be fitted if required. The empennage was simple in shape and action as there were no fixed surfaces only an all-moving rudder and elevator. Both control surfaces were balanced. The conventional undercarriage was also very simple, with the mainwheels attached to a single axle which passed through the fuselage, sitting the L.66 close to the ground. The tailskid was linked to the rudder for steering on the ground
- Haake engine.
- Slightly larger and heavier, with Stahlwerk Mark St.M3 or Anzani engine.
- Lighter version, Bristol Cherub or Anzani engine. Two built.
Specifications (Haake engine)
Data from Flight, 6 June 1924, pp.385
- Capacity: Two
- Length: 5.40 m (17 ft 9 in) 
- Wingspan: 9.00 m (29 ft 6 in) 
- Wing area: 13.5 m2 (145 sq ft)
- Empty weight: 220 kg (485 lb)
- Gross weight: 395 kg (871 lb)
- Fuel capacity: 33 L
- Powerplant: 1 × Haake air-cooled, horizontally opposed two cylinder, 22 kW (30 hp)
- Propellers: 2-bladed
- Maximum speed: 100 km/h (62 mph; 54 kn)
- Endurance: 3 hr at full power
- Time to altitude: about 15 min to 1,000 m (3,280 ft)