The 1938 Pretty Prairie Special I, designed by Marion Unruh, was based on the Knight Twister. An open cockpit biplane, N25460 was built by George Albright.
The 1928 United Aircraft Corp / UAC Special was designed by F R McConigal as a two or foup place biplane. The one built had a four place cabin which modified to a two place open cockpit, or vice-versa. It was registered NX5613 and powered by a 225hp Wright J-5.
The Union Pfeil-Doppeldecker was designed by Josef Sablatnig and/or Walter Höhndorf, and/or Karl Bomhard, characterized by the swept-back wings with unusual upturned lower wing tips, and built in Berlin-Teltow. It won four prizes at the Wiener International Flag-Meeting 1913, fitted with a 120 hp Austro-Daimler engine. Previous and later versions with other engines were successful in several meetings and set altitude records.
The Aeroplane is a single seat single engined biplane with two-axis control. Wings have swept back leading and trailing edges, and constant chord; no tail, elevator only. Pitch control by elevator at rear; yaw control by tip rudders; no separate roll control; control inputs through stick for pitch/yaw. Wings braced by struts and transverse X cables; wing profile; double surface. Undercarriage has three wheels in tricycle formation; bungee suspension on all wheels. Nosewheel steering independent from yaw control. Brake on nosewheel. Aluminium tube framework, without pod. Engine mounted between wings driving pusher propeller. Designed by Larry Mauro, under the original title of Icarus II as a hang glider, this famous biplane was one of the first hybrid control hang gliders to be motorised (in 1975 by John Moody). It then pursued a remarkable career under the name of Easy Riser; by 1981 more than 900 were flying in the United States, built from plans supplied by the Larry, or sold as kits by different firms such as UFM of Kentucky.
Since 1981, this company has offered it with an elevator added at the back of the interplane struts, in which form it carries the name Aeroplane. It is fitted with two axis control and there is a fixed seat for the pilot, the hybrid control with the pilot moving in a swing seat having been abandoned. The rudders on the standard Aeroplane are hinged on the rear interplane struts at the wing tips. The engine is the Cuyuna 215R of 20hp, which as an option ($300) can be replaced by the 430R as on the Aeroplane XP, the three axis control version. The Aeroplane is sold either ready to fly for $5200 in 1983, or as a kit requiring 150h assembly for $3995. Options include floats for $900, transport covers for $250, skis, parachute and an instrument panel. Whereas UFM of Kentucky has fitted the Easy Riser with a conventional tail giving rise to the Aeroplane (a 1983 model), Northstar had preferred a canard of variable incidence, thus acting as an elevator, for its Viking. This rigid wing biplane has retrofit horizontal tail and strong spars. A joystick controls the elevator and drag tip rudders. Side mounted joy stick, rudder pedals, nose wheel steerable through rudder pedals. Single-cylinder Cuyuna 215R engine has reduction drive and is pusher mounted in the rear behind the pilot. It turns a 50-inch prop. Tricycle gear has 20-inch wheels which are shock cord mounted and a 16-inch nosewheel with a wheel brake. The Aeroplane XP is a single seat single engined biplane with conventional three axis control. Wings have swept back leading and trailing edges, and constant chord; conventional tail. Pitch control by elevator on tall; yaw control by fin mounted rudder; roll control by spoilerons on upper wing; control inputs through stick for pitch/roll and pedals for yaw. Wings braced by struts and transverse X cables; wing profile; double surface. Undercarriage has three wheels in tricycle formation; bungee suspension on all wheels. Push right go right nosewheel steering connected to yaw control. Brake on nosewheel. Aluminium tube framework, with optional pod. Engine mounted between wings driving pusher propeller. The Aeroplane XP is basically a three axis version of the Aeroplane with a twin cylinder engine. The design abandons the tip rudders of the Aeroplane in favour of a conventional tail, the stick and pedal arrangements being similarly conventional, with the stick mounted on the side of the framework. One interesting point, however, is that both spoilers can be simultaneously deployed to act as air brakes; this is quite a common arrangement with pedal actuated spoilers, but most unusual when the spoilers are actuated by the stick. Options for the Aeroplane XP are as for the Aeroplane, except that UFM of Kentucky announced in March 1983 that a pod was available for the XP. Price is $4500 and the XP can be folded into a package measuring some 2 x 4 x 16 ft (0.6 x 1.2 x 4.9 m), allowing trailer or car top transport. Rigging time is quoted as 50 min by one person.
Aeroplane Engine: Cuyuna 215R, 20hp at 5500rpm Propeller diameter and pitch 54 x 20 inch, 1.37 x 0.51 m Reduction ratio 2.0/1 Power per unit area 0.12hp/sq.ft, 1.3hp/sq.m Fuel capacity 5.0 US gal, 4.2 Imp gal, 18.9 litre Length overall 11.0 ft, 3.35 m Height overall 8.0ft, 2.44m Wing span 30.0ft, 9.14m Constant chord 3.4ft, 1.04m Dihedral 15 deg Sweepback 15 deg Total wing area 170 sq.ft, 15.8 sq.m Upper wing area 102.5 sq.ft, 9.52 sq.m Lower wing area 67.5 sq.ft, 6.27 sq.m Upper wing aspect ratio 8.8/1 Lower wing aspect ratio 5.8/1 Wheel track 4.5 ft, 1.37 m Wheelbase 4.5 ft, 1.37 m Nosewheel diameter overall 20 inch, 51 cm Empty weight 180 lb, 82 kg Max take off weight 400 lb, 181 kg Payload 220 lb, 100kg Max wing loading 2.35 lb/sq.ft, 11.5kg/sq.m Max power loading 20.0 lb/hp, 9.1kg/hp Load factors +6.0, 4.0 design; +10.0, 5.0 ultimate Never exceed speed 50 mph, 80 kph
Aeroplane XP Engine: Cuyuna 430R, 34hp at 6000rpm Propeller diameter and pitch 54 x 30 inch, 1.37 x 0.76 m V belt reduction, ratio 2.0/1 Max static thrust 250 lb, 113 kg Power per unit area 0.20 hp/sq.ft, 2.2 hp/sq.m Fuel capacity 5.0 US gal, 4.2 Imp gal, 18.9 litre Length overall 11.0 ft, 3.35 m Height overall 8.0ft, 2.44m Wing span 30.0ft, 9.14m Constant chord 3.4ft, 1.04m Dihedral 15 deg Sweepback 15 deg Total wing area 170 sq.ft, 15.8 sq.m Upper wing area 102.5 sq.ft, 9.52 sq.m Lower wing area 67.5 sq.ft, 6.27 sq.m Upper wing aspect ratio 8.8/1 Lower wing aspect ratio 5.8/1 Wheel track 4.5 ft, 1.37 m Wheelbase 4.5 ft, 1.37 m Nosewheel diameter overall 20 inch, 51 cm Tailplane span 8.5ft, 2.59m Fin height 3.5ft, 1.07m Empty weight 225 lb, 102 kg Max take off weight 475 lb, 215 kg Payload 250 lb, 113kg Max wing loading 2.79 lb/sq.ft, 13.6kg/sq.m Max power loading 14.0 lb/hp, 6.3kg/hp Load factors +6.0, 4.0 design; +10.0, 5.0 ultimate Max level speed 55 mph, 88 kph Never exceed speed 55 mph, 88 kph Max cruising speed 50 mph, 80 kph Economic cruising speed 40 mph, 64 kph Stalling speed 22 mph, 35 kph Max climb rate at sea level 1200 ft/min, 6.1 m/s Min sink rate 290 ft/min at 30 mph, 1.5 m/s at 48 kph Best glide ratio with power off 8/1 at 28 mph, 45 kph Take off distance 75 ft, 23 m Landing distance 100 ft, 30 m Service ceiling 18,000 ft, 5490 m Range at average cruising speed 125 mile, 201 km
Aeroplane XP-2 Engine: Cuyuna, 43 hp or Rotax 47 hp Wingspan: 32 ft Wing area: 196.5 sq.ft Empty wt: 250 lbs Max wt: 700 lbs Cruise: 55 mph Stall: 26 mph Vmax: 63 mph ROC: 600 fpm TO run: 100 ft Ldg roll: 100 ft