The two-seat ‘Humming Bird’ was originally designed by William E. Hunt. It was developed in 1947 by Frontline Helicopter Corp. as the ‘Flyride’ and the prototype (N544A) made its first flight in January 1948. It was a streamlined all-metal monocoque helicopter with an automobile-style forward fuselage and forward-swept rotor pylon. Power was provided by a 125hp Lycoming engine. The engine is in the aircraft’s nose, but instead of the five controls common to conventional aircraft, the Flyride has only two primary control units: a stick with a motorcycle grip, and a throttle. The stick, which rests on an arm between the two seats, governs all movements on the horizontal plane: an accelerator of the type used in motor vehicles controls upward and downward movement by means of a governor geared to the engine, and the pitch of the blades is regulated by the engine’s output in terms of revolutions per minute.
Since the cyclic control system is replaced by a fully tilting head, the rotor has no hunting hinges or drag hinges.
Frontline Helicopter was acquired by Glenview Metal Products and the machine became the GMP-1 Flyride. Glenview Metal Products Aircraft Division includes Robert Mattox, who was formerly aircraft designer with the Pitcairn Aviation Corporation and works manager with Piasecki Helicopter Corporation. In 1954 Glenview revived the prototype helicopter designed by William E. Hunt, with Hunt himself as consulting engineer. It was upgraded with a 135hp Lycoming in 1953 and was advertised to the public as the ideal personal helicopter.
GMP.I Flyride Number of seats: 2 Engine: Lycoming, 135hp Rotor diameter: 9.3m / 30 ft. 6 in Rotors: 2-blade main; 2-blade tail. Length: 10.82m Height: 2.62m Weight fully loaded: 750kg / 1,655 lb Empty weight: 522kg Cruising speed: 144km/h Inclined climb: 366m/min Absolute ceiling: 3810m Range: 448km Typical range: 280 miles at 90 m.p.h.
Construction of the replica Curtiss H-1 America began in the spring of 2004 and a total of 6000 man hours went into the construction at the Glenn H. Curtiss Musem at Hammondsport, New York. It has been built using the same materials as the originals with the exception of the glue and fabric covering. At Keuka Lake, New York, attempts were made to fly the replica but despite rigging changes and engine tuning it refused to fly.
The engines were then changed from the 90 hp OX-5 units to counter rotating OXX-6 of 100 hp. The aircraft then flew at Keuka Lake, New York on 13-14 September 2007, piloted by Jim Poel.
Initially referred to as the Speed Queen SQ2000, the SQ2000 was a new design following the lines of the Velocity etc., but with more rounded fuselage lines. The SQ2000 was designed by Stan Montgomery, and the prototype (which had the undercarriage of an Infinity) made its first flight in 1997 under the power of one 200hp Lycoming IO-360-C1A engine.
prototype N10736
The basic SQ2000 could be completed as a 2-seater with as very large baggage compartment or as a 4-seater.
Paul Lee’s SQ2000 N416 fully retractable undercarriage
The SQ2000 features a cantilever mid-wing with tip rudders and a canard, a four-seat enclosed cabin accessed via doors, fixed or optionally retractable tricycle landing gear and a single engine in pusher configuration. The aircraft is made from composites. Its 26.58 ft (8.1 m) span wing has a wing area of 104.0 sq ft (9.66 m2). The cabin width is 48 in (120 cm). The acceptable power range is 160 to 260 hp (119 to 194 kW) and the standard engine used is the 200 hp (149 kW) Lycoming IO-360 powerplant.
N440DH, David Hanson’s SQ2000, fixed main gear
Like many canard designs, the SQ2000 has lengthy runway requirements. The standard day, sea level take-off run is 1,600 ft (488 m), while the landing roll is 1,500 ft (457 m).
The SQ2000 lacks flaps and has a high landing speed. The overall cabin height of the SQ2000 has more headroom since the seats are mounted lower. The kit is more complete as it uses molded wings and canards.
Several examples had been completed and flown by 2005, including one by Mr. Paul Lee with one 200 hp Franklin 6A-350-C2 engine and one by Mr. David Kanson with one 200 hp Lycoming IO-360 engine.
SQ2000 aircraft were observed with Velocity style undercarriage (retracting into the fuselage) and with a KLS-developed undercarriage, which had straight undercarriage members retracting inwards into the wings.
Paul Lee’s N416 fully retractable undercarriage
One particular SQ2000 was christened the Rotor-EZ by its builder, Paul Conner, who fitted one Mazda 13B rotary engine instead of the typical Lycoming, and a one-piece wooden propeller.
Paul Conner’s Rotor-EZ during construction
The aircraft made its first flight on 11 December 2004, but was lost in a fatal accident in May of the following year.
Rotor-EZ
Conner Rotor-EZ
Several models were planned for amateur construction and available from Glassic Composites, LLC, which planned various models: the SQ2000 XP, similar to the SQ2000, but with lower empty weight and suited for 150-200hp engines such as one Lycoming O-320 or Lycoming O-360 series (one example seems to have been built but probably not completed); the SQ2001, a three-seater with a passenger in the rear of the cabin; and the SQ2002, a so called 2+2 version with children’s seats. Yet none of these variants was built, and when
The SQ2000 was available with fixed or retractable undercarriage. The basic structures are moulded with spars. The SQ2000 first flew in 1993. The kit price in 1997 was US$22,000 for the SQ2000, and US$34,900 for the SQ2000 XP.
Less than a dozen aircraft were either completed or in construction in 12 years, and only eight on the US civil register. One reason probably lies in Glassic’s lack of credentials and the subsequent takeovers of the company’s assets.
Known completions are; SQ2000 N10736 (prototype), N416, N330DW, N2396M, N2366R, N206SQ, and N440DH. SQ2000 XP N971CL and the Rotor-EZ N2992P.
Glassic Composites ceased its activities and as of 1999, and was taken over by KLS Composites, a company formed by SQ2000 builders Messrs. Keith Register and Stan Montgomery.
Wing area: 104.2 sq.ft MTOW: 2250 lb Empty wt: 1100-1250 lb Useful load: 1000 lb Payload w/full fuel: 748 lb Max wing load: 21.0 lb/sq.ft Pwr load: 11.0 lb/hp Cabin length: 83 in Cabin width front: 47 in Cabin width rear: 42 in Cabin head room: 41 in
Prototype Engine: 1 x 200 hp Lycoming IO-360-C1A Wingspan:27.8 ft. Length: 16.85 ft. Height: 7.83 ft Maximum speed: 258 mph Cruise speed: 225 mph ROC: 2,.200 ft./minute Ceiling: 25,000 ft. Range: 800 miles
SQ2000 Top speed: 250 mph Cruise: 230 mph Stall: 67 mph Range: 900 sm Rate of climb: 2200 fpm Takeoff dist: 1700 ft Landing dist: 1700 ft Service ceiling: 25,000 ft Engine: Lycoming IO-360, 200 hp HP range: 150-250 Fuel capacity: 42 USG Empty weight: 1200 lb Gross weight: 2250 lb Height: 7.8 ft Length: 17.5 ft Wing span: 28.7 ft Wing area: 104 sq.ft Seats: 4 Landing gear: retractable nose
SQ2000 XP Top speed: 270 mph Cruise: 235 mph Range: 1035 sm Rate of climb: 2200 fpm Takeoff dist: 1500 ft Landing dist: 1500 ft Engine: Lycoming IO-360C-1C, 200 hp HP range: 150-200 Fuel capacity: 52 USG Empty weight: 1100 lb Gross weight: 2100 lb Height: 7.8 ft Length: 17.4 ft Wing span: 28.6 ft Wing area: 104 sq.ft Seats: 4 Landing gear: retractable nose or retractable tail
SQ2000 XP Powerplant: 1 × Lycoming O-360, 200 hp (150 kW) Wingspan: 26 ft 7 in (8.10 m) Wing area: 104.00 sq ft (9.662 m2) Length: 17 ft 6 in (5.33 m) Empty weight: 1,200 lb (544 kg) Gross weight: 2,250 lb (1,021 kg) Fuel capacity: 42 U.S. gallons (160 L; 35 imp gal) Maximum speed: 260 mph (420 km/h, 230 kn) Cruise speed: 230 mph (370 km/h, 200 kn) Range: 851 mi (1,370 km, 739 nmi) Service ceiling: 25,000 ft (7,600 m) Rate of climb: 2,200 ft/min (11 m/s) Wing loading: 21.6 lb/sq ft (105 kg/m2) Crew: one Capacity: three passengers
Paul Lee’s N416 (The following are at 1850 lbs. & 117 CG) Empty weight : 1410 lbs. (1394 lbs. without 9 qt. oil) Engine : Franklin 6A-350-C2, 200 hp Propeller : 66″ 3 blade, IVO magnum in-flight adjustable Fuel Capacity : 35 gal. (includes 2.25 gal. in supplementary tank) Landing gear: all-three wheels retractable Climb: 2000 ft./min (105kts, 2000 dens alt.) Ceiling: 18,000+ ft. (still doing 200+ ft./min) Best glide ratio : @ 19:1 (105 kts., 3000 dens alt.) Fuel efficiency : best about 5 gal. per hour near 120 kts. Canard stall : 66 kts. Takeoff distance : @ 1500 ft., rotate at 80 kts. (IVO electric adjustable prop.) Landing rollout distance: approx 2000ft Speed: 180 kias (3000 dens alt., 2800 rpm) Crew/passengers: 2-4
Regarded as having one of the highest performances of any sailplane when it was first rolled out at the end of 1962, the BS 1 had a prone position for the pilot to keep the fuselage cross section as small as possible, as well as a braking parachute housed in the T-tail.
It was designed by Bjorn Stender, who had worked on the SB-6 when a student at Akaflieg Braunschweig and who in 1962 had been asked to design and build a high performance sailplane by the South African pilot and industrialist Helli Lasch. He set to work with only three other helpers and in spite of the BS 1’s advanced nature they succeeded in finishing it by the end of 1962; it was of glassfibre construction – still a comparative novelty at that time – and also had camber changing flaps. The BS-1 has airbrakes, retractable wheel and a tail chute.
After completing its flight tests the BS 1 broke the 300km (186 mile) international triangular speed record during the spring of 1963 and also had a number of competition successes. The BS-1 won the world 300 km speed record (135.3 kph / 85.94 mph) set by Alfred Rohm of West Germany in 1967. In 1970 Terry Thys of San Leandero, Ca made a 917 km / 570 mile flight; which was then the third longest in soaring history.
But following the death of Bjorn Stender on a test flight in October 1963 the type was taken over by the Glasflugel company, who produced the modified BS 1B, which first flew on 24 May 1966. This featured a redesigned fuselage to provide a roomier cockpit, and a modified wing of increased span and a new Eppler 348 aerofoil section to give improved soaring capabilities in weak thermals. Glasflugel built a total of 18 BS 1Bs, one of these being supplied to the naturalist and sailplane pilot Sir Peter Scott.
BS 1B Wing span: 18m / 59ft Aspect ratio: 23 Wing area: 14.1 sq.m / 151.7 sq.ft Wing section: Eppler 348 Length: 7.5 m / 24 ft 7.5 in Height: 1.54 m / 5 ft 0.5 in Empty Weight: 335 kg / 739 lb Payload: 125 kg / 275 lb Gross Weight: 460 kg / 1014 lb Water ballast: None Wing Load: 32.62 kg/sq.m / 6.68 lb/sq.ft Max speed: 155 mph / 135 kt / 250 km/h Stalling speed: 35 kt / 65 km/h Max rough air speed: 135 kt / 250 km/h L/DMax: 44 at 95 kph / 51 kt / 59 mph MinSink: 0.54 m/s / 1.78 fps / 1.05 kt at 53 mph / 46 kt / 85 km/h Water Ballast: 0kg / 0lb Seats: 1 No. Built: 18
The 604 high performance single-seater by Hanle and Prosser is a 22m span version of the Kestrel 17, and in fact originated as a design study for a similar two-seater sailplane.
Originally intended as a development vehicle for a two-seat high performance sailplane, the 604 has a three-piece wing weighting more than 272 kg/ 600 lb.; just the center section weights 160 kg/ 353 lb. The wing has six flaps, the outer pair of which move at a 2:1 differential with the ailerons. Large spoilers deploy from the upper wing surface only, and there is a tail chute for added approach control.
The 604’s wing consists of a centre section incorporating the fuselage top, and two outer panels joined to the centre section by the Hutter-Hanle method. The fuselage is 5ft 5in longer than the Kestrel 17’s to give improved directional control with the longer span wing; the cockpit canopy, which is slightly shorter than the Kestrel’s, is hinged to open upward and aft. There is a manuallly retractable monowheel with a brake, and a fixed tailwheel. Structurally the 604 is very similar to the Kestrel 17, and can carry up to 220lb of water ballast.
The prototype made its first flight in April 1970, only four months after construction began, and took part in the 1970 World Gliding Championships at Marfa, Texas, taking sixth place; it later took second place in the 1974 World Championships at Waikerie, Australia.
Only 10 604s were built but the type gained a number of competition successes and has set several world and national records, including one for speed over a 300km triangle, set by W. Neubert of West Germany in Kenya in March 1972 with a speed of 95.3mph, and the ladies’ 100km triangular speed record of 79.1mph set by Adele Orsi of Italy in August 1975.
Wing span: 22m / 72 ft 2 in Wing area: 16.26 sq.m / 174.7 sq.ft Length: 7.6 m / 24 ft 11.25 in Height: 1.67 m / 5 ft 5.75 in Empty Weight: 420 kg / 926lb Payload: 180 kg / 397 lb Gross Weight: 600 kg / 1230 lb Wing Load: 36.9 kg/sq.m / 7.57 lb/sq.ft Water Ballast: 0 kg / 0 lb Max speed: 135 kt / 250 km/h / 155mph (smooth air) Stalling speed: 34.5 kt / 64 km/h L/DMax: 49 at 98 kph / 53 kt / 61 mph MinSink: 0.50 m/s / 1.64 fps / 0.97 kt at 45mph / 39 kt / 72 km/h Aspect ratio: 29.8 Airfoil: Wortmann FX-67-K-170/150 Seats 1 No. Built 10
Designed by Hanle and Prasser, the 17m Kestrel high performance Open Class single-seater was designed to meet the demand for a successor to the Libelle variants with a longer wing span and roomier cockpit; it was known originally as the 17m Libelle and has a new fuselage and wing profile and a T-tail. The fuselage is a fiberglass monocoque (not sandwich) for greater resilience and pilot protection. The cockpit has room enough for a 198 cm / 6 ft pilot and features a control stick that slides fore and aft (rather than rotating) to reduce likelihood of pilot induced oscillations and which has a press-to- trim-push-button trimmer. It has a nose and a center of gravity release.
The cantilever two piece shoulder wings are of glassfibre and balsa and/or foam sandwich construction, with unidirectional glassfibre spar caps and glassfibre and balsa shear webs. To cure a small airflow separation problem at the wing root fuselage junction at low speeds large wing root fillets were added to production aircraft; these were actually developed by Vickers-Slingsby, who built the Kestrel 17 under licence. High lift camber-changing flaps are featured which operate in conjunction with the ailerons between 8° and +12°, and can be lowered to 35° for a landing; both ailerons and flaps are partially mass-balanced. It features airbrakes, drogue chute, water ballast and retractable gear. Up to 99lb of water ballast can be carried. There are flush fitting air brakes on the wing upper surfaces, and also a tail braking parachute which can be streamed for short-field landings.
The Kestrel 17 tail unit is similar in construction to the wings, the fixed T-tail being secured by three attachments. Both the elevator and rudder are mass balanced. The monowheel is retractable, with an internally expanding brake, and there is an interchangable tailwheel or tailskid.
The prototype Kestrel first flew at Karlsruhe-Forchheim on 9 August 1968 and production deliveries began the following year, reaching a total of 129 by January 1978.
Kestrel 17m
The Kestrel 17 has several records to its credit. Goran Ax won the second Smirnoff Transcontinental Sailplane Race in a Kestrel in 1973. Sue Martin of Australia gained both the womens world 100 km speed record (113.2 kph / 70.36 mph ) and 300 km triangle speed record (114.4 kph/ 71.11 mph). The 100km closed circuit speed record of 102.74mph was set by K. B.Briegleb of the USA on 18 July 1974 (since broken by an AS-W 17), and the ladies’ 300km closed circuit speed record of 71.1mph set up by Susan Martin of Australia on 11 February 1972.
Glasflugel 401 Kestral 17
The Italian firm of Glasfaser Italiana SrL has also built 25 Kestrel 17s, as well as 130 complete fuselage assemblies for the Kestrel.
After Slingsby Aircraft Company Ltd had gone into liquidation in July 1969 the firm was reorganised as part of the Vickers Group, at first as Slingsby Sailplanes, later trading as Vickers-Slingsby and then as Slingsby Engineering Ltd. It was decided in September 1969 to produce a modern glassfibre design, and a licence to build the Kestrel was negotiated with Glasflugel. Construction of the first Slingsby-built T 59 Kestrel 17 began in March 1970, and it first flew on 15 August that year at Rufforth, Yorkshire.
Slingsby Glasflugel Kestrel
After putting the Glasflugel Kestrel 17 into production, Vickers-Slingsby (later Slingsby Engineering Ltd) began to pursue its own line of development of this Open Class single-seater, which resulted in the 19m span T59B, T59C and T59D. The first 19m span Kestrel, the T 59B, being flown by Mr G Burton in the 1970 World Championships in Texas. The 19m T 59C, which had a carbon-fibre main spar, first flew on 7 May 1971. This was followed by the T 59D of the same span, which first flew in July 1971, the extra span being in the form of 0.5m at each wing root and 0.5m at each wing tip. The T 59D also featured a larger fabric-covered rudder and an antibalance tab in the elevator.
Slingsby T59D ZK-GHU
The D model was still further developed into the T59H of 22m (72ft 2.25in) span, the extra span consisting of two 1.5m stub wings inserted into the exisiting wing at the roots. The fuselage is similar to the Kestrel 17 up to just aft of the canopy, beyond which an additional section 29 1/2 in long is inserted which considerably reduced the ‘waisting’ of the earlier version. The fin and rudder area are increased by about 25%, although the tailplane is the same size as the Kestrel 17’s; the rudder is lightened to prevent flutter by fabric-covered cut-out sections.
The T.59H Kestrel 22 is a special version of the single-seat high performance Kestrel 19 and the prototype was built by using a Kestrel 19 with two 1.5 metre stub wings, complete with flaps, inserted at the wing roots and an extra fin extension mounted above the tailplane. The idea was to make these modifications available to any owner of the Kestrel 19 who wanted to increase the performance of his sailplane.
Two prototype T59Hs were built, the first of these flying in 1974, but the new variant was found to suffer from a wing flutter at 140kts (161mph); Vickers-Slingsby had to recover the prototype T59H from the original customer who had bought it, while the flutter problem was investigated by the College of Aeronautics, where it was still being studied early in 1978.
T.59H Kestrel 22
Like the T59C, the H has a carbon-fibre main spar and, apart from the longer fuselage and long-span four-piece wing, joined at the flap/aileron junction, incorporate carbon-fibre spars and large Schempp-Hirth airbrakes on both upper and lower surfaces, it is structurally similar to the Kestrel 17 with the same cantilever T-tail, up to 220lb of water ballast can be carried. There are Schempp-Hirth air brakes in the upper and lower wing surfaces, and there is a monowheel. The two T59H prototypes are known as the Kestrel 22 Series 1 and Series 2.
The fuselage has been lengthened by 750 mm (2 ft 4½ in) by adding a section to the 19m Kestrel just aft of the wing trailing edge. The tail unit is like that of the Kestrel 19 with the weight of the rudder reduced to prevent flutter by cutting panels out of the glassfibre skin and covering with fabric. Landing gear comprises a large retractable unsprung Gerdes monowheel with a disc brake, plus a fixed tailwheel. The disc brake is operated by a hydraulic unit coupled to the airbrake system.
The T59H was abandoned in favour of a new aircraft, the Kestrel 22.
A total of 101 Kestrels had been built by Vickers-Slingsby by the end of 1974, plus two 22m span T 59H Kestrel 22s. Most of these have been 17m span versions.
Slingsby T-59H Span: 22.0 m / 72 ft 2.25 in Length: 7.55 m / 24 ft 9.25 in Height: 1.94 m / 6 ft 4.25 in Wing area: 15.44 sq.m / 166.2 sq.ft Aspect ratio: 31.35 Wing section: Wortmann FX-67-K-170/150 Empty weight: 390 kg / 860 lb Max weight: 659 kg / 1,453 lb Water ballast: 100 kg / 220 lb Max wing loading: 42.68 kg/sq.m / 8.74 lb/sq.ft Max speed: 155 mph / 110 kt / 204 km/h (in smooth air) Max aero-tow speed: 93 mph / 105 kt / 194.6 km/h Min sinking speed: 0.48m/sec / 1.57 ft/sec at 53 mph / 46 kt / 85 km/h Best glide ratio: 51.5:1 at 64.5 mph / 56 kt / 104 km/h
Intended to succeed the Mosquito B, the 15m span Glasfliigel 304 single-seater is a new design very similar to the Mosquito, work on which began in the autumn of 1979 by a team under Martin Hansen.
Construction is of glassfibre, with no carbon-fibre employed, although the 304/17 (now known as the Glasflugel 402), which has detachable wing tips to give a span of 17m, has largely carbon-fibre wing tips. It employs a new 16.4% thickness/chord ratio wing profile developed by Akaflieg Braunschweig and extensively tested and refined on a Mosquito. It features Glasflugel trailing edge dice brakes and interconnected variable camber flaps, a parrallogram control stick, T-tail with fixed stabilizer and elevator, and automatic connection on assembly of all flight control. The fuselage is similar to the Mosquito’s but with a more pointed nose; the monowheel is retractable. The instrument panel can be tipped up, together with the front-hinged upwards opening canopy, with which it is integral, to allow the pilot more unobstructed entry. Up to 253lb of water ballast can be carried.
The prototype, D-9304, first flew on 10 May 1980. Production of the 304 started in the spring of 1981.
Glasflugel 304 CZ
HPH Ltd. took over the original molds and drawings for glider Glasflugel 304 from Mr. George Brauchle in 1998.
402 Span: 55 ft 9.25 in Length: 21 ft 2in Height: 4 ft 5.5 in Wing area: 114 sq ft Aspect ratio: 27.3 Empty weight: 518lb Max take-off weight: 992lb Max speed: 156mph (smooth air) Min sinking speed: 2.26ft/sec at 58mph Best glide ratio: 43:1 at 72mph
Designed by Eugen Hanle for the 15 m racing class, the Mosquito is a development of the Club Libelle and differs from the earlier Hornet chiefly in having carbon-fibre mass-balanced ailerons, and a new flap/spoiler/air brake system.
Design of the Mosquito was started in the summer of 1975 and the Mosquito’s construction is generally similar to the Hornet, except for the ailerons, and up to 253lb of water ballast can be carried. The structure is fiberglass, with CFRP wing box spar and skin. The new flap/air brake system was developed jointly by Klaus Holighaus and Eugen Ha’nle; conventional camber-changing trailing edge flaps act in conjunction with spoilers immediately ahead of them in the wing upper surface to act as a trailing edge air brake. The normal flap lever lowers the flaps and droops the ailerons in conjunction with them, while there is a second lever for the spoilers or brake flaps. As this is pulled, the spoilers start to open and further backward movement movement of this lever moves the flaps further downwards as well as opening the spoilers further. The latter can be opened or closed at any time like the more conventional Schempp-Hirth type air brakes fitted to other sailplanes. The tailplane at the top of the fin is fixed incidence, and the elevator has spring trim. The retractable unsprung monowheel has an internally expanding brake, and there is a fixed semi-recessed tailwheel. The one-piece canopy is raised by the pilot to hinge forward onto the nose tip for exit.
The prototype first flew in March 1976, it was the first type to go into production after the reorganisation of the Glasflűgel company under the name Holighaus & Hillenbrand GmbH & Co K.G following the death of its Director, Ing Eugen Ha’nle, on 21 September 1975. Dipl-lng Klaus Holighaus, the Director of Schempp-Hirth and Herr Hillenbrand of Glasflűgel formed the present company, continuing to market them under the Glasflűgel name.
A total of 90 Mosquitos had been delivered by January 1978.
Glasflűgel began building the prototype of a new version, the Mosquito B, in September 1977. This differs from the standard Mosquito in having glassfibre reinforced plastic ailerons, no fuselage/wing root fairings, a reduced wing span and a tailplane of reduced span. Empty weight is reduced to 518lb but maximum weight and performance are the same as the standard Mosquito. First flight was on 24 March 1978 and about 90 Mosquito Bs had been delivered by January 1980.
Mr Humphrey Dimock, who runs the Royal Naval Gliding Club at Lee-on-Solent in Hampshire, has fitted a Mosquito with a 36-cell solar panel in the cockpit to charge a German Dry-Fit 14 volt battery at a rate of 0.46A when in sunlight; spare capacity generated by the panel can power blind flying instruments if necessary and there is a cut-out to prevent overcharging. The panel weighs only a few ounces and is mounted directly in front of the pilot edge-on to his line of sight so as not to restrict visibility. Following the success of this panel Mr Dimock planned to fit 10 solar cells in a 5ft x 3.5in strip along the top of the fuselage under a Perspex fairing.
In 1954 Eugen Hänle was then Assistant Professor Ulrich Hütter in a company engaged in the manufacture of large wind turbines for electricity production. The design of the 17 meter blades used fiber reinforced plastic glass.
With this experience, Eugen Hänle established Glasflügel in 1957, to produce helicopter rotor blades for Bölkow.
Meanwhile, Hütter had developed the H-30TS glider, derived from the H-30, with a modified fuselage to accommodate a small BMW turbojet and a new wing of 15 m with plastic flaps, but with glued aluminum sheet metal spar. Hänle then used the molds to produce wings in the Schempp-Hirth workshop. Two sets of wings with glass fiber spar were made. One of the wings was the first H-301 Libelle (or Dragonfly), other than the first Swiss Diamond, with its original 15 m wingspan.
Designed by Wolfgang Hutter and Eugen Hanle, the Libelle first flew on 6 March 1964 and became the first fiberglass sailplane to receive an U.S. ATC. Although of Standard Class span, its camber-changing flaps and manually retractable monowheel put it into the Open Class; it could, however, be flown with flaps up and wheel locked down to conform with the then Standard Class rules. The two-piece cantilever mid wings are glass-reinforced plastic/balsa sandwich structure with a single spar web and no ribs; the glassfibre spars are joined at the fuselage by a tongue/fork type of junction which was later to be adapted in a number of other sailplane designs. The mass-balanced ailerons are linked differentially with the flaps, and there are Hütter air brakes, each 8 ft 2.5 in long, forward of the flaps. The wing leading edge has a compartment for water ballast, of which 110 lb can be carried.
The fuselage is an all-glassfibre monocoque with balsa and synthetic foam and an integral fin; and the rest of the tail unit is of the same type of construction as the wings. The pilot sits in a semi-reclining position under a rearward-sliding one-piece canopy to reduce fuselage cross-section and hence drag, and a slightly higher canopy could be fitted if the customer so desired; there is provision for radio and oxygen, and the seat backrest and rudder pedals are adjustable in flight. The monowheel is mounted on a glassfibre shock absorber and has a brake; it is supplemented by a sprung tailskid or tailwheel.
In 1969 Soaring magazine readers voted the Libelle the World’s most beautiful sailplane. The H 301 Libelle has camber-changing flaps and was able to compete both in the Open Class and, with locked flaps, in the Standard Class.
A total of 111 Libelles had been built when production finally ceased in 1969.
Libelle 301 Wing span: 15 m / 49.2 ft Wing area: 9.5 sq.m / 102.25 sq.ft Aspect ratio: 23.6 Wing section: Hutter Length: 6.2 m / 20 ft 4 in Height: 2 ft 7.8 in (wheel up) Empty Weight: 180 kg / 397 lb Gross Weight: 300 kg / 661 lb Payload: 120 kg / 264 lb Water ballast: 50 kg / 110 lb Max speed (smooth air): 155 mph / 135 kt / 250 km/h Stalling speed: 35 kt / 65 km/h Max aero-tow speed: 84 mph Max rough air speed: 86.5 kt / 160 km/h Wing Load: 31.25 kg/sq.m / 6.4 lb/sq.ft L/DMax: 39 at 95 kph / 51 kt / 59 mph MinSink: 0.55 m/s / 1.8 fps / 1.07 kt at 46.5mph / 40.5 kt / 75 km/h Seats: 1
