In 1973 aircraft manufacturer Heinrich Brditschka and an engineer with the Graupner model-building company, Fred Militky, enlisted the collaboration of Bosch (propulsion motor) and Varta (nickel-cadmium battery technology) to study the feasibility of an all-electric aircraft.
They converted an HB-3A motor glider into the first electric manned airplane: the MB-E1 (Militky-Brditschka Elektroflieger No. 1).
On 21 October 1973, the MB-E1 took to the skies in Wels, Austria with Heinrich’s son, Heino Brditschka, at the controls. The maiden flight lasted for about 9 min and achieved an altitude of 300 m. However, further advancement in battery and motor technology would be required to achieve practical electric flight.
The HB-21, which first flew in 1973, is basically an enlarged version of the HB-3 with an increased wing span and a lengthened forward fuselage seating two people in tandem under a long three-piece cockpit canopy hinged to open sideways.
The HB-3’s basic configuration of high wings and a pusher propeller rotating in a cut-out portion of the fuselage is retained. Construction is very similar to the HB-3, the fabric-covered three-piece wooden wings being of birch ply with laminated beech spars; they now have Wortmann aerofoil sections and there are spoilers in the upper surfaces. The fuselage is a steel tube framework covered with glassfibre, and the wooden tail unit has a fixed-incidence tailplane and fabric covered control surfaces. The fixed nosewheel undercarriage has Tost mechanical brakes on the main wheels.
Four prototypes were built which included both the HB-21 R with a 41 hp Rotax 642 two-stroke engine like the HB-3, and the HB-21 L with a 65hp Volkswagen(VW)-Westermayer 1600G ‘flat four’ motor, the latter being the principal version; both powerplants drove a Hoffman HO 14-175 B 117 LD two-blade fixed-pitch propeller, and both versions have an 11.9 Imp gallon aluminium fuel tank in the wing.
Certification of the HB-21 was granted in February 1978, and a year later 15 had been built.
HB-21L Span: 53 ft 3.5 in Length: 25 ft 11 in Height: 8 ft 6.25 in Wing area: 204.3 sq ft Aspect ratio: 13.89 Empty weight: 1,102 lb Max weight: 1,565 lb Max speed: 124 mph (in smooth air, power off) Max cruising speed: 99 mph Min sinking speed: 3.94 ft/sec at 52 mph Best glide ratio: 24-26:1 at 65 mph Max rate of climb: 650 ft/min at sea level Take-off run: 330 ft Range with max fuel: 497 miles
HB-21 R Engine: Rotax 642, 30.6 kW / 41 hp Wing span: 16.24 m / 53 ft 3.5 in Length: 7.9 m / 25 ft 11 in Height: 2.6 m / 8 ft 6.25 in Wing area: 18.98 sq.m / 204.3 sq ft Wing section: Wortmann FX-61-184/60-126 Aspect ratio: 13.9 Empty weight: 418 kg / 922 lb Max weight: 640 kg / 1,411 lb Water ballast: None Max wing loading: 33.7 kg/sq.m / 6.9 lb/sq.ft Max speed: 140 kt / 260 km/h Stalling speed: 35.5 kt / 66 km/h Min sinking speed: 0.8 m/sec / 2.6 ft/sec at 43 kt / 80 km/h Best glide ratio: 28 at 54 kt / 100 km/h T-O run: 170 m / 558 ft Rate of climb: 132 m/min / 433 ft/min at S/L Range: 650 km / 350 nm
Designed by Heinz W. Brditschka and built by his firm at Linz in Austria, the HB-3B is a single-seater cantilever high wing monoplane distinguished by a pusher propeller rotating in a triangular cut-out in the glassfibre-covered tubular steel framework carrying the tail. This consists of two steel tubes, the upper one running through the centre of the propeller and the lower one from the bottom of the fuselage just under the propeller disc; the forward fuselage containing the engine and cockpit is likewise a steel tube framework covered with glassfibre. The HB-3 uses the basic wing design of the Kra’he sailplane designed in Germany by Ing Fritz Raab; the wing is a conventional all-wood structure of red pine, spruce and birch ply, with spoilers in the upper surfaces; no flaps or trim tabs are fitted.
Design of the HB-3 started in 1968 and the first of three prototypes made its maiden flight on 23 June 1971, followed by the second on 5 June 1972 and the third on 28 July 1972. Nine production HB-3s had been completed by early 1976, but production ended that year.
The HB-3’s standard powerplant was a 41 hp Rotax 642 two-stroke ‘flat twin’ mounted aft of the cockpit and driving a Hoffman two-bladed fixed-pitch propeller via a belt; the fuel used is a 75/25% petrol and oil mixture, and there is a single fuel tank in the fuselage and an aluminium tank in the wing centre-section, which together provide a total capacity of 8.15 Imp gallons. The tail unit is of all-wood construction, with wire bracing from the fin to the centre section trailing edges; the fixed incidence tailplane has a trim tab in the starboard elevator. The fixed nosewheel undercarriage has glassfibre legs which provide all the necessary shock absorption without the need for separate shock absorbers. The main wheels have Tost mechanical brakes. The pilot sits under a large cockpit canopy that hinges to open sideways to starboard; there is a small baggage space behind his seat and a ram air intake in the nose is provided for cabin ventilation.
Heinz W. Brditschka also converted an HB-3 airframe in 1973 to have electric power, in which form it was known as the Militky MB-E1.
Variation: Militky MB-E1
HB-3B Span: 39 ft 4.5 in Length: 22 ft 11.75 in Height: 9 ft 8 in Wing area: 153.1 sqft Aspect ratio: 10.11 Empty weight: 573 lb Max weight: 837 lb Max speed: 108 mph (in smooth air, power off) Max cruising speed: 99 mph Min sinking speed: 3.77 ft/sec at 45.5 mph Best glide ratio: 20:1 at 50 mph Take-off run to 50ft: 755 ft Range with max fuel: 341 miles
HB-3BR Engine: Rotax 642, 30.6 kW / 41 hp Wing span: 12.0 m / 39 ft 4.5 in Length: 7.0 m / 22 ft 11.5 in Height: 2.95 m / 9 ft 8 in Wing area: 14.22 sq.m / 153.1 sq ft Wing section: Gottingen 758/Clark Y Aspect ratio: 11.1 Empty weight: 255 kg / 562 lb Max weight: 372 kg / 820 lb Water ballast: None Max wing loading: 26.2 kg/sq.m / 5.36 lb/sq ft Max speed: 95 kt / 175 km/h Stalling speed: 32.5 kt / 60 km/h Min sinking speed: 1.15 m/sec / 3.8 ft/sec Best glide ratio: 21 at 43 kt / 80 km/h T-O run: 100 m / 328 ft Rate of climb at S/L: 180 m/min / 590 ft/min Range: 700 km / 378 nm
The 1909 Brauner and Smith biplane was designed and built by Pincus Brauner and A. J. Smith, who were members of Aeronautic Society of New York, Morris Park. Their biplane was the second aircraft of the Society to fly. Both Brauner and Smith made numerous flights in the machine proving its airworthiness. Later, the aircraft was exhibited at Madison Square Garden. Eventually Brauner, while attempting to reach a greater height, raised his front control too acutely, and fell backwards, almost totally destroying the machine, but he escaped unhurt.
Brantly produced an enlarged B-2, named the Model 305 which had a longer forward fuselage providing a rear 3-passenger bench seat. The new five seater (N2200U) made its first flight in January 1964, powered by a 305hp Lycoming IVO-540-A1A engine and received its type certificate on 29 July 1965. The cabin has two bucket seats forward, seating for three aft, capacity for 200 lb of baggage, can fly 120 mph and sold for $48,900.
Brantly immediately commenced production but the Model 305 suffered from persistent ground resonance problems and they only built 45 examples.
It differs from the B2B externally by having a small variable-incidence tail-plane, and an enlarged cabin accommodates a total of five persons on two side-by-side forward seats, and an aft bench seat for three. The rotor system and airframe was the same as the B-2B, but enlarged and conventional direct mechanical flying controls.
The landing gear was a choice of skid, wheel or float gear. Skid type has four oleo struts, two on each side, and small retractable ground handling wheels. Wheel gear has single mainwheels and twin nosewheels, all with oleo-pneumatic shock-absorbers of Brantly manufacture. Goodyear mainwheels and tyres size 5.00-5, pressure 1.93 bars. Goodyear single-disc hydraulic brakes on mainwheels.
The 227.4kW Textron Lycoming IVO-540-B1A flat-six engine, was mounted vertically, with dual cooling fans. One rubber fuel cell under engine, capacity 163 litres. Refuelling point in port side of fuselage. Oil capacity 9.5 litres.
A rear compartment for 113kg of baggage, with downward hinged door on starboard side.
Model 305
44 were built during the 1960s and another four built by Hynes Aviation in 1985 as the H-5. Michael K. Hynes, owner of the type certificates, established Brantly-Hynes Helicopter Inc. on 1 January 1975, initially to provide product support for the large number of Brantly helicopters in use. He subsequently started up a production line for the B-2B, and also the larger Model 305.
Improved prototype with redesigned rotor head and new blade aerofoil completed about 30 hours flying by mid-January 1990. New main rotor bearing fitted. Cabin streamlined. New production was to begin 1993, but none built.
Engines: Lycoming IVO-540-B1A, 305 hp, 227kW Main rotor diameter: 8.74m Fuselage length: 7.44m Height: 2.44m Disc loading: 4.5 lb/sq.ft. Pwr loading: 9.5 lb/hp. Max TO wt: 1315kg, 2900 lb. Empty wt: 816kg, 1732 lb. Equipped useful load: 1106 lb. Payload max fuel: 854 lb. Range max fuel/ cruise: 199 nm/ 1.9 hr. Range max fuel and payload: 354km Service ceiling: 3660m, 11,000 ft. Max speed: 193km/h Max cruise: 177km/h, 104 kt. Max range cruise: 95 kt. ROC: 975 fpm. HIGE: 4000 ft. HOGE: 1500 ft. Max sling load: 800 lb. Fuel cap: 252 lb. Seats: 5.
Developed from coaxial twin-rotor B-1 by Newby Brantly, the B-2 with single main rotor and anti-torque tail rotor configuration first flew on 21 February 1953. An improved second prototype flew on 14 August 1956. This was to enter production in 1958 receiving FAA certification on 27 April 1959.
1955 B-2
A total of 194 B-2s and 18 B-2As (with additional headroom) were produced between 1960 and 1963 and the improved Model B-2B with metal rotor blades and fuel-injected Lycoming IVO-360-A1A engine was certified on 1 July 1963. A total of 165 were built between 1963 and 1967 (the company owned by Gates Learjet from 1966).
B2A
Type certificates for the Brantly Bs were purchased in 1971 by Michael Hynes and revised as the 2 H2/YHO 3BR. Michael K. Hynes established Brantly-Hynes Helicopter Inc. on 1 January 1975, initially to provide product support for the large number of Brantly helicopters in use. He subsequently started up a production line for the B-2B and built one (as H-2) in 1975, and also the larger Model 305. James T. Kimura was the third owner of the B-2 type certificate, and delivered his first B-2B on 25 August 1990. Brantly Helicopter Industries (BHI) took over manufacturing and marketing rights and production facilities in 1989 with three were built under this name, which received the FAA production certificate on 19 July 1996. The first new-build B-2B (N25411 c/n 2001) was flown on 12 April 1991. In 1992, a B-2B cost US$120,000 to US$135,000 depending on equipment fit. On 23 December 1994, Brantly International obtained the type certificates for the Brantly B-2B and 305 helicopters from Japanese-American businessman James T Kimura’s Brantly Helicopter Industries, which had acquired them in May 1989. In 2002, Brantly employed 40 in its 2,790 ha facility. By 2002, Brantly Helicopter Inc of Vernon, Texas were again producing the B2B.
Brantly B2B
British Executive Air Services had acquired a production licence for the B-2. In 2003 the cost was US$170,000 basic equipped.
A relatively simple design, with blown main transparency and constant-taper fuselage. Double-articulated three-blade main rotor with pitch-change and flapping hinges close to hub and flap/lag hinges at 40% blade span; symmetrical, rigid, inboard blade section with 29% thickness/chord ratio, outboard section NACA 0012; outer blades quickly removable for compact storage; rotor brake standard; two-blade tail rotor mounted on starboard side, with guard. Transmission through automatic centrifugal clutch and planetary reduction gear. Bevel gear take-off from main transmission, with flexible coupling to tail rotor drive-shaft. Main rotor/engine rpm ratio 1:6.158; tail rotor ratio 1:1. Main rotor minimum speed 400 rpm; maximum 472 rpm. Conventional and manual controls; small fixed tailplanes on port and starboard sides of tailcone. A semi-monocoque fuselage with alloy-stressed skin. Inboard rotor blades have stainless steel leading-edge spar; outboard blades have extruded aluminium spar; polyurethane core with bonded aluminium envelope riveted to spar. All-metal tail rotor blades. Fixed skid type landing gear with oleo-pneumatic shock-absorbers; small retractable ground handling wheels, size 10×3.5, pressure 4.12 bar; fixed tailskid. Optional inflatable pontoons attach to standard skids for over-water operation. One 134kW Textron Lycoming IVO-360-A1A flat-four air-cooled piston engine, mounted vertically. Fuel contained in two interconnected bladder tanks behind cabin, total capacity 117 litres of which 115 litres are usable. Oil capacity 6.9 litres. Two seats, side by side in enclosed cabin; forward-hinged door on each side. Dual controls and cabin heater standard. Ground accessible baggage compartment, maximum capacity 22.7kg in forward end of tailcone.
In 1959 the Army procured five examples of the Brantly Model B-2 light helicopter for evaluation in the observation role. The five machines obtained by the Army (serials 58-1492 through -1496) were designated YHO-3 and tested at both Fort Rucker and the Naval Air Test Center at Patuxant River, Maryland. The aircraft was ultimately judged to be too small to be of practical military use and all five examples were eventually returned to the manufacturer.
Brantly B-2B
B-2 Engine: Lycoming 135 hp Rotors: 3-blade main 2-blade tail Rotor diameter: 23 ft Loaded weight: 1,250 lb Seats: 2
B2B Engines: Lycoming IVO-360-A1A, 180 hp,134kW. Main rotor diameter: 7.24m Fuselage length: 6.63m Height: 2.06m Disc loading: 3.7 lb/sq.ft. Pwr loading: 9.3 lb/hp. Max TO wt: 1670 lb / 757kg Empty wt: 1032 lb / 463kg Equipped useful load: 576 lb. Payload max fuel: 390 lb. Range max fuel/ cruise: 152 nm/1.8 hr. Range max fuel / range: 196 nm/ 2.3 hr. Service ceiling: 12,500 ft / 3290m Max speed: 161km/h Max cruise: 87 kt / 145km/h Max range cruise: 87 kt. ROC: 1400 fpm. HIGE: 4300 ft. HOGE: 2500 ft. Max sling load: 400 lb. Fuel cap: 186 lb. Seats: 2.
2 H2/YHO 3BR Engine: Lycoming IVO-360-A1A, 180 hp. TBO: 900 hrs. Main rotor: 23.7 ft. Length: 28 ft. Height: 6.8 ft. Max ramp weight: 1670 lbs. Max takeoff weight: 1670 lbs. Standard empty weight: 1069 lbs. Max useful load: 601 lbs. Zero fuel weight: 1490 lbs. Max landing weight: 1670 lbs. Max sling load: 400 lbs. Disc loading: 3.7 lbs/sq.ft. Power loading: 9.3 lbs/hp. Max usable fuel: 183 lbs. Max rate of climb: 1330 fpm. Service ceiling: 12,500 ft. Hover in ground effect: 4,300 ft. Hover out of ground effect: 2500 ft. Max speed: 87 kts. Normal cruise @ 3000 ft: 78 kts. Fuel flow @ normal cruise: 72 pph. Endurance @ normal cruise: 2.4 hr. Seats: 2.
Brantly B-2B Engine: Lycoming IVO-360, 180 hp Rotor span: 7.24 m Blade area: 0.203 sq.m MAUW: 757 kg Empty weight: 463 kg Max speed: 161 kph Cruise speed: 145 kph Climb rate: 9.6 m/s Seats: 2
In 1943, N. P. Brantly began the design of a lightweight helicopter, built and flown in 1946 under the designation Brantly B-1. The B-1 was constructed by his employer, the Pennsylvania Elastic Company. Brantly used a coaxial twin-rotor configuration but the design was too heavy and complicated to appeal. With two co-axial contra-rotating three-bladed rotors, neither push rods nor cranks were visible in the rotary wing assembly. The collective, cyclic and differential controls were completely enclosed in the hubs and ran in an oil-bath. The three-blade rotors had a fixed pitch central “star” and a universal joint combining two hinges was 1.8 metres from the root of the blades. The radius of the non-flapping part of the blades was 1.8 metres. Each blade weighed only 5.5 kilos and the rotors normally turned at 320 r.p.m. The B-1 prototype (NX69125) was powered by a 150hp Franklin engine in the tube and fabric fuselage and had a fixed tailwheel undercarriage and directional control was achieved through a small rudder on the sternpost – because the twin main rotors were expected to neutralise the normal torque effect.
B-1 Number of seats: 2 Engine: 1 x Franklin 335, 150hp Rotor diameter: 9m Length: 5.33m Height: 2.36m Weight fully loaded: 907kg Empty weight: 601kg Cruising speed: 182km/h Range: 640km
Since 1921, some 120 examples of the Austro¬Hungarian Brandenburg C.1 reconnaissance and light bomber aircraft, series 269, were manufactured at the first Romanian aircraft factory, Arsenalul Aeronauticii, in Bucharest. These airframes were equipped with 220hp (164kW) and 250hp (186kW) Daimler Benz, MARTA Benz and NAG engines, captured in 1919 from Hungary.
A man who became well-known in the automobile and motorcycle field, Granville Bradshaw, was responsible for the design and construction of the Star mono-plane.
It was based on the Antoinette, and of similar dimesions, both machines having a span of 42 feet.
However the French machine had a much larger wing area of 538 square feet compared to 290 square feet for the Star, and the Antoinette was something like 5 feet longer at 37ft 7inches and 200lbs heavier than the British machine.
The Star power plant was a 4-cylinder water-cooled 30/40hp unit, very similar to their car engine
The Star was listed to sell at less than half the £1,000 asked for the Antoinette.
The Bradley Pitbull was designed as a first time builders project for assembly in 250 hrs. No jigs or alignment beams are needed, and no special tools required. Of all metal construction, there is no bending, forming or welding to do. Only 2024 T3 Aircraft grade aluminum is used for skins, wing ribs and bulkheads. All skins, ribs and bulkheads are blind riveted. With spring undercarriage, the front gear is castering. The kit also includes a carbon fiber canopy frame and windshield bow, and F-15 style canopy. Matco wheels and brakes and tires are included. Wing tips with inset lighting and strobes and all hardware are included in kit. 4130 steel tube pushrod controls and housed push pull cables are fitted and a 46 US gallon fuel capacity. The Pitbull is available as a tricycle or tail wheel versions, and it accepts the Lycoming O-320 or )-360 or any 100 to 200 Hp engines. The Pitbull qualifies in the Experimental (150-200HP) and Light Sport category (100hp). The Speed wing has a 9+ 9- g rating (Aerobatic).
