Huetter H 30
| Huetter H 30 | |
|---|---|
| Type: | Glider |
| Design country: | |
| Manufacturer: |
Hütter / Hänle |
| First flight: |
H 30 GFK: May 5, 1962, |
| Commissioning: |
- |
| Production time: |
- |
| Number of pieces: |
2 |
The Hütter H 30 was a single-seat glider design by the German designer Wolfgang Hütter from 1948, which formed the basis for later designs by the manufacturer Glasflügel . The aim was to use the H 30 as a club aircraft, which should offer a low purchase price, increased flight performance compared to conventional gliders and improved ease of maintenance.
history
Wooden shell construction
Towards the end of the Second World War, Wolfgang Hütter developed the idea of also building gliders based on the principle of wooden shell construction. The bulging , load-bearing outer skin eliminates the need for support elements such as ribs, stringers , frames and spars . Until then, this method, which, in addition to reducing costs, offered the advantage of significant weight savings, had only been used on a few combat aircraft. Examples are the Bachem Ba 349 Natter and the Focke-Wulf Ta 154 .
Due to the lightweight construction , the same wing loading and flight performance should be achieved as with aircraft with large wingspan . Hütter hoped that the design would also make it easier to handle in the air and on the ground. In addition, the transport of the aircraft would also become easier and, moreover, production should become faster and simpler. The plywood - balsa- shell construction of the wing would achieve a high profile accuracy over the entire span. The fuselage was to be partly made from multiple glued poplar veneer.
The first beginnings of building an H 30 were made in Breitenbach / Switzerland between 1949 and 1950, but they were not completed. In 1955 Eugen Hänle joined the project. When trying to implement it again, it quickly became clear that the workshop drawings were missing important details that had to arise during construction. First a wing sample was made, from which it became clear that the required weight would not be achievable with the planned construction and the materials available at the time. Even optimistic mass estimates showed that the finished aircraft was at least 20% overweight. In addition, there were assemblies that could not be manufactured in the intended manner. The attempt at conventional production in wood was dropped again.
GRP shell construction
Since the engineers Hütter and Eugen Hänle already had extensive experience with the manufacture of fiber optic components (Hütter-Hänle process), it was decided to at least partially implement the project using fiberglass. The wings received straps made of parallel glass fibers instead of balsa wood. These glass fibers were wrapped around the connecting eyes on the wing root and then ran back into the wing. The wing connection fittings, which were very complicated on other aircraft, are simply glued into the wings of the H 30. The formerly wooden wing bridge was now also made of GRP, which meant a time and cost saving of around 50%. This also reduced the weight of the wing bridge by almost 50%. In the wing bridge, too, the connecting eyes were wrapped with fiberglass in accordance with the force line and thus also "glued in".
Many other changes such as exchanging the landing skid for a wheel, unconventional bearing of the control rods and a number of constructive optimizations meant that the prototype of the Hütter H 30 GRP only slightly exceeded the planned maximum weight. The entire rear part of the fuselage including the tail unit weighed only 7.5 kg. For the first time in aviation history, many components previously made of wood were consequently rethought and manufactured in fiberglass-reinforced plastic.
First flight and flight characteristics
On May 5, 1962, the H 30 GFK took off from Hahnweide with test pilot Lindner . The maiden flight was unproblematic until landing. On the final approach, however, the airbrake mechanism fails and the H 30 GFK needs the entire length of the airfield to come to a stop. After another attempt in June of the same year with the same problem, modifications to the airbrakes followed in the winter of 1962/63. At the end of April 1963, the revised aircraft took off for the first time with Dipl.-Ing. Eugen Hänle at the wheel. The flight is unproblematic.
Hänle described the flight characteristics of the H 30 GRP as sensitive and comparable to the characteristics of an AV-36 . It reacts quickly and you only need a few rudders to turn . Overall, the rudder forces are very low. The minimum speed is Hänle in flight report at 70 km / h on.
Ten years later, Ursula Hänle further developed the H 30 into the H-101 Salto glass wing .
Construction (H 30)
Wings
The wooden shell construction would have enabled a high wing aspect ratio of 22.3 combined with high strength ( intercepting load multiple of 5.5). The wing shell should be made of 4 to 8 mm thick plywood. The profile was a modification of the Gö 600 and the P-51 Mustang laminar profile, which was removed from a captured specimen in 1944 and was also intended for the Horten H IVa . In order to be able to change the profile curvature, a system of adjusting screws should be installed on the lower half of the shell.
hull
The wooden shell construction should also be used here. In order to be able to achieve the smallest possible fuselage cross-section, the fuselage-wing transition was included in the optimization efforts as an elbow space, a principle that W. Hütter had tried out as early as 1935 when building the H-28 and later when building the Gö 4 . A folding runner with suspension and shock absorber and a sprung spur were provided as the chassis.
Tail unit
The tail unit was designed as a damped V-tail unit , which should offer the following advantages:
- 10 percent reduction in tail resistance
- Reduction of the interference resistance on the tail unit
- Only two tail surfaces, these can be designed interchangeably
- Greater ground clearance than with a conventional cross tail unit
Problems in development and manufacturing
When developing the H 30 GRP, Hänle and Hütter could not fall back on experience from similar projects, as they were doing pioneering work in the field of glass fiber composites in aviation. Although the material was already known in the aviation industry and used to a small extent, not many manufacturers dared to undertake such a project before the H 30. Almost all problems that arose during production and development were solved by the two designers on their own. The designers were also not supported financially. Even an application for exemption from the examination fees for the type certification was not granted, as the project did not justify this. Parallel to the production and development of the H 30, they jointly built the Glasflügel company . This explains the long time of seven years from the start of the project to the maiden flight.
H 30 TS
In addition to the non-built H 30 and H 30 GRP, a variant as a jet-powered motor glider was developed by Wolfgang Hütter without Eugen Hänle's collaboration and built at the Allgaier machine factory in Göppingen from 1959 to 1960. The Hütter 30 TS has been optimized for series production and equipped with the BMW 8026 jet engine . The wing, which was enlarged from 13.60 m to 15 m, received a double-T duralumin spar, the new Hütter H-300 wing profile, a flap and a 2.40 m wide Schempp-Hirth brake flaps located far back . While the first version still had the V-tail and a retractable skid and main wheel, the second version used a steerable nose wheel and a damped cross tail. After the first flight on August 20, 1960, the first self-launch followed on September 25, 1960. With the registration number D-KABA, Heinz Kensche took part in the German Gliding Championship in Freiburg in 1961 .
However, due to problems with the turbine and a lot of noise, the project was discontinued and the aircraft was dismantled to a pure glider D-9344. The aircraft was lost in a serious winch launch accident on the Klippeneck in August 1968 .
Technical specifications
| Parameter | H 30 (calculated) | H 30 GRP | H 30 TS |
|---|---|---|---|
| crew | 1 | ||
| length | 5.44 m | 5.56 m | 5.70 m (6.10 m with cross tail ) |
| span | 13.60 m | 15.00 m | |
| height | 1.05 m | 1.32 m ( vertical stabilizer ) | |
| Wing area | 8.30 m² | 8.34 m² | 9.53 m² |
| Wing extension | 22.3 | 22.2 | 23.6 |
| Wing profile | Hutter | Huetter H-300 | |
| V position | 2.5 ° | ||
| Glide ratio | 30 at 80 km / h | 33 at 85 km / h | |
| Slightest sinking | 0.65 m / s at 62 km / h | 0.64 m / s at 65 km / h | |
| payload | 95 kg | 90 kg | |
| Empty mass | 120 kg | 195 kg | |
| Max. Takeoff mass | 190 kg | 210 kg | |
| Top speed | 250 km / h | 140 km / h | |
| Engine | - | a BMW 8026 | |
See also
literature
- Karl R. Pawlas: Aviation Lexicon, Hütter H 30 . Entry ID 2143-100-1.
- Karl R. Pawlas: Aviation Lexicon, Hütter H 30 TS . Entry ID 2132-100-1.
- Jürgen Gaßebner: The most beautiful vintage gliders . 1st edition, Motorbuchverlag 2002, ISBN 3-613-02195-1 .
- Aerokurier, edition 9/1963.