Rhein-Flugzeugbau X-114

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RFB X-114
X-114 during testing on the Baltic Sea X-114 during testing on the Baltic Sea
Type: Ground effect vehicle
Design country:

Germany Federal RepublicFederal Republic of Germany BR Germany

Manufacturer:

Rhein-Flugzeugbau GmbH

First flight:

April 15, 1977

Commissioning:

1977

Production time:

1977

Number of pieces:

1

The RFB X-114 was a six-seater ground effect vehicle from Rhein-Flugzeugbau from 1977, which was suitable for flights close to the ground using the ground effect as well as for flights in areas far from the ground. The test vehicle was developed at the instigation of the Federal Ministry of Defense in order to provide practical evidence of the usefulness of ground-effect vehicles for transport and surveillance tasks in the high seas.

history

The RFB X-114 continued the series of test vehicles for ground-effect studies begun by Alexander Lippisch with the Collins X-112 and the RFB X-113 . Like its two predecessors, the X-114 was primarily designed for efficient, ground-level locomotion using the ground effect. At the same time, as a flying boat, it should also be able to reach greater altitudes. After the basic principles of the ground effect and their use with the RFB X-113 could be adequately demonstrated with test flights on Lake Constance and on the Weser until 1972, Alexander Lippisch and Hanno Fischer intended to build a larger vehicle that would prove its suitability for the ocean on the one hand but also the commercial use of the ground effect should prove for the first time. In 1974, Lippisch and Fischer submitted a draft of a 300-ton flying boat to the Ministry of Defense, which should have an operating range of 2000 km over a 20-hour period. The Federal Ministry of Defense commissioned Rhein-Flugzeugbau in February 1975 with the development of another test boat with which the operational profile of the design by Lippisch and Fischer was to be verified. The test vehicle should be able to accommodate six passengers or the equipment for submarine and sea reconnaissance and should be operational in typical sea conditions.

construction

The RFB X-114, unlike the trimaran X-113, was designed as a catamaran. According to the Lippisch principle, the X-114 received an inverted delta wing. The GRP fuselage is designed as a closed hose construction. A 200 HP Lycoming IO-360 motor was used as the drive, which drove a jacketed screw on the fuselage. In order to be able to operate on land, the X-114 received a retractable landing gear. The X-114 received various innovations, which should primarily influence the use of the ground effect. This included a variable float, the rerouting of the exhaust air from the drive under the dam and a flap control.

Construction phase and testing

As with the X-113, Lippisch and Fischer began preliminary tests on remote-controlled flight models in 1975, which were initially intended to demonstrate the new technologies on a small scale. Shortly before construction of the actual test vehicle began, Alexander Lippisch died on February 11, 1976 in Cedar Rapids, USA. Volkmar Wilckens then took on the role of scientific director in the X-114 project. The first flight under the leadership of Wilckens took place on April 15, 1977. The test program at RFB comprises 25 flights with a total duration of 7.5 hours. During the test, Wilckens developed a real-time device for determining wave height and length, whose signals were connected to the control of the X-114. After the flight tests had demonstrated sufficient stability and controllability, the X-114 was handed over to test center 71 of the Bundeswehr in Eckernförde for offshore testing and given the military test license “98 + 29”. The flying boat showed stable operating behavior during the test. Problems arose, however, with the longitudinal stability. For this reason, the X-114 was modified several times during testing, including the X-114 hydrofoils for longitudinal stabilization. During one of the test flights to test the hydrofoils, the X-114 undercut the water surface. When the hull subsequently hit the water, the boat was largely destroyed.

Technical specifications

Parameter RFB X-114 RFB 215 RFB SSF-I
crew 1 1
Passengers 5 5
length 12.83 m 12.80 m 22.00 m
span 7.00 m 7.00 m 12.40 m
height 2.92 m 2.90 m 6.50 m
Wing area 29.10 m² 29.10 m² 100.00 m²
Wing extension
Glide ratio
Slightest sinking
payload 460 kg 690 kg 4500 kg
Empty mass 1040 kg 840 kg 5500 kg
Max. Takeoff mass 1500 kg 1530 kg 10000 kg
Cruising speed 150 km / h 150 km / h 100 km / h
Top speed
Service ceiling 800 m 1.5 m
Range 2000 km 2350 km 800 km
Engines a Lycoming IO-360 , 200 hp a Lycoming IO-360, 260 hp two P&W PT6 , 550 kW (748 PS)

Follow-up drafts

After the failure of the test vehicle, Hanno Fischer submitted drafts for a new test vehicle to the Federal Ministry of Defense.

  • RFB 215 - 1530 kg takeoff weight, 1460 nm range
  • RFB X-117 - 4-5-seater taxi ram boat, also offered as a customs surveillance boat in Thailand
  • RFB Riverbus 15-15 seated taxi and ferry ram boat
  • RFB SSF-I - 30-seat ferry-ram-wing boat with 10 tons take-off weight, with 2 × 748-PS-P & W-PT6 engines, 500 nm range

The Federal Ministry of Defense was no longer interested in a further development of the ram boats. Third parties such as customs and police were also not interested in developing such vehicles at the end of the 1970s. Rhein-Flugzeugbau then ended its ground effect activities in the early 1980s.

Hanno Fischer then took over the development of Rhein-Flugzeugbau and continued ground effect research with Klaus Matjasic in his engineering office Fischer Flugmechanik, founded in 1979, independently of RFB, at his own expense.

Patents from the X-114 development

  • DE2508205A1 - variable float, Feb. 1975
  • DE2540847A1 - diversion of draw air under the baffle, Sept. 1975
  • DE2547945A1 - flexible, lightweight wing for storage wing vehicles, Oct. 1975
  • DE2627389A1 - Flap controls for storage wing vehicles, June 1976

Comparable types

Related developments

See also

literature

  • Paul Zöller: Rhein-Flugzeugbau GmbH and Fischer Flugmechanik . 1st edition, 2016, BoD-Verlag, ISBN 978-3-7431-1823-2 .

Web links

Individual evidence

  1. ^ Paul Zöller: Rhein-Flugzeugbau GmbH and Fischer Flugmechanik , 2016, ISBN 978-3-7431-1823-2
  2. ↑ RFB product folder X-114, RFB-215
  3. ↑ Hanno Fischer: Variable geometry float for hydrofoil . DE2508205 A1, February 26, 1975 ( google.com [accessed on May 23, 2017]).
  4. ^ Hanno Fischer: ground effect vehicle . DE2540847 A1, September 13, 1975 ( google.com [accessed on May 23, 2017]).
  5. ^ Hanno Fischer: Wing training for storage wing vehicles . DE2547945 A1, October 27, 1975 ( google.com [accessed on May 23, 2017]).
  6. ↑ Hanno Fischer: Flap arrangement for ground effect vehicles . DE2627389 A1, June 18, 1976 ( google.com [accessed on May 23, 2017]).