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Neukom AN-20


Single-seat single-engined high-wing monoplane with conventional three-axis control. Wing has unswept leading and trailing edges, and constant chord; T-tail. Pitch control by elevator on tail; yaw control by fin-mounted rudder; roll control by one-third-span ailerons; control inputs through stick for pitch/roll and pedals for yaw. Wing braced from below by struts; wing profile Wortmann FX 63-137; double-surface. Undercarriage has three wheels in tricycle formation with tailskid; no suspension on nosewheel and glass-fibre suspension on main wheels. Push-right go-right nosewheel steering connected to yaw control. Brakes on main wheels. Glassfibre fuselage, partially enclosed. Engine mounted at wing height driving pusher propeller. Wing and T-tail have wood spars, ribs in styrofoam and covered with expoxied glassfibre.

His first microlight made its first flights in 1978, the prototype AN-20 using a T-tail carried on a Kevlar spar of round section. Connected to the fuselage at the same height as the wing, the tubular fuselage carried basically a mono-wheel undercarriage but with an additional nosewheel steerable from the rudder bar, the main wheel being positioned directly below the wing. Moreover, the vertical fin below the fuselage spar was provided with a tailwheel in line with the other two.

This machine was shown in various publications under the designation of AN-20M, which was a great surprise to Albert Neukorn, who tells us that he had never called this first model by any other name than AN-20, except that it eventually became AN-20A to disting-uish it from the later AN-20B. The prototype was shown at the European homebuilders meeting at Brienne in July 1982.

The AN-20B is directly evolved from its predecessor whose rectangular plan form wing it has retained, supported by a profiled strut under each half wing. A significant change is the inclusion of air brakes, while the AN-20B is provided in addition with an elegant glass-fibre fairing with windscreen encompassing all the forward section of the fuselage as far as the trailing edge of the wing, where it joins the spar carrying the tail. Another important difference from the AN-20A is that this spar is no longer level with the wing but mid-mounted, a change which required a re-design of the T-tail. As a result, the fin and rudder no longer continue below the spar. The engine, previously fitted below the spar is now carried by a tubular structure above the rear spar, effectively level with the wing. Production models use the three cylinder Konig SC430 driving a three-bladed pusher propeller. Finally, a last important modification, the AN-20B replaced the single main wheel undercarriage of the AN-20A with a tricycle undercarriage whose main wheels are fitted with drum brakes.

The AN-20B was still produced by Albert Newkom himself in 1983, either ready-to-fly ex works without engine or as a set of plans. An attempt to set up production facility in France with the AN-20B in 1981 has been abandoned.

Length overall 17.7 ft, 5.40 m
Height overall 3.9ft, 1.20m
Wing span 41.3ft, 12.60m
Constant chord 2.611, 0.80m
Dihedral 2 degrees
Sweepback 0 degrees
Tailplane span 8.0ft, 2.45m
Fin height 3.2ft, 0.95m
Total wing area 109sq.ft, 10.1sq.m
Total aileron area 8.5 sq.ft, 0.79 sq.m
Fin area 6.6 sq.ft, 0.61 sq.m
Tailplane area 8.4 sq.ft, 0.78 sq.m
Total elevator area 4.2 sq.ft, 0.39 sq.m
Wing aspect ratio 15.8/1
Wheel track 4.7ft, 1.43m
Nosewheel diameter overall 8 inch, 21 cm
Main wheels diameter overall 8.5 inch, 22cm
Engine: Konig SC430, 24 hp at 4200 rpm
Propeller diameter 42 inch, 1.06 m
Belt reduction, ratio 1.8/1
Max static thrust 121 lb, 55 kg
Power per unit area 0.22 hp/sq.ft, 2.4 hp/sq.m
Fuel capacity 5.3 US gal, 4.4 Imp gal, 20.0 litre
Empty weight 287 lb, 130 kg
Max take-off weight 508 lb, 230 kg
Payload 221 lb, 100 kg
Max wing loading 4.68 lb/sq.ft, 22.8 kg/sq.m
Max power loading 21.2 lb/hp, 2.4kg/hp
Load factors; +5.3, -2.6 ultimate
Max level speed 93 mph, 150 kph
Never exceed speed 99 mph, 160 kph
Max cruising speed 68 mph, 110 kph
Economic cruising speed 59 mph, 95 kph
Stalling speed 31 mph, 50 kph
Max climb rate at sea level 500 ft/min, 2.5 m/s
Min sink rate 160 ft/min at 37 mph, 0.80 m/s at 60 kph
Best glide ratio with power off 18/1 at 37 mph, 60 kph
Take-off distance 360 ft, 110 m
Land-ing distance 330 ft, 100m
Service ceiling 11,500 ft, 3500 m
Range at average cruising speed 186 mile, 300km



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