Lunar Landing Training Vehicle

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LLRV in flight (1964)
LLRV No. 2 in flight (January 11, 1967)

The Lunar Landing Research Vehicle (short LLRV , Eng. For Moon Landing experimental unit) and the Lunar Landing Research Vehicle (short LLTV , Eng. For Moon Landing exerciser) are of the Dryden Flight Research Center of NASA as part of the Apollo program developed aircraft to Researching and practicing a manually controlled landing on the moon . Their spartan structure as an uncovered aluminum tube frame earned them the nickname “Flying Bedstead” (“Flying Bed Frame ”).

development

To train the moon landing, NASA implemented three concepts: an electronic simulator, a movable suspended platform (in the form of the Lunar Landing Research Facility ) and a free-flying simulator.

Since some engineers of the Bell Aerosystems Company had already given some thought to such a free-flying moon landing simulator, the company was offered a contract for 50,000 US dollars by NASA to develop a concept in December 1961 . Upon completion of the study, NASA commissioned Bell in February 1963 to produce two LLRVs with the following characteristics:

  • Take off and landing on your own
  • Flight altitude 1200 m above ground
  • Ability to hover and move horizontally
  • Flight time of 14 minutes

construction

The LLTVs are structures made of aluminum tubing, four landing legs around a triangular platform. The cockpit protrudes between two legs, and an electronics platform between the opposite legs.

In the center of gravity of the vehicle there is a General Electric CF700-2V jet engine in a gyro-stabilized platform that always keeps the engine vertical, regardless of the flight position. By regulating the thrust of the engine to 5/6 of the weight of the LLTV, the gravitational acceleration on the moon can be simulated, which is 1/6 of the gravitational acceleration on earth.

In addition, a system of lift and control rocket motors is installed, which simulate the lift and control system of the Apollo lunar module as precisely as possible. The Lage engines use hydrogen peroxide as fuel, which is pumped via a helium pressure system.

The cockpit was supposed to imitate the control of the lunar module, accordingly a fly-by-wire system was installed, which was controlled by a joystick and pedals. 3-axis control sticks were installed in the LLTVs, which made the pedals superfluous and thus simulated the control of the lunar module even better. An artificial horizon and radar-controlled speed indicators provided realistic displays. In addition, an ejection seat and a control unit for the jet engine were installed.

Mission history

After a loss of control, the pilot of LLTV-B2 was able to save himself from a crash on January 29, 1971 with an ejector seat

Both LLRVs were delivered to NASA in April 1964. The following September, the first engine tests on the ground were carried out at Edwards Air Force Base , and finally the maiden flight of LLRV No. 1 with Joseph Albert Walker at the controls took place on October 30th . The aircraft has been extensively tested and was able to record over 175 flights within two years. Based on the results of the tests, NASA ordered three LLTVs from Bell in mid-1966, which were named LLTV B1, LLTV B2 and LLTV B3.

In late 1966, NASA centralized the training program at the Manned Spacecraft Center in Houston , where LLRV No. 1 was transported in December. The first flight of LLRV No. 2 took place in January 1967, after five more flights it was then also brought to Houston. There both LLRVs received modifications that put them on an equal footing with the slightly more advanced LLTVs. The new names for the LLRVs were now LLTV A1 and LLTV A2.

In the course of the training program, three LLTV crashed, but in all cases the pilots were able to save themselves with the ejection seat:

  • LLTV A1 with pilot Neil Armstrong lost helium pressure in the fuel tanks at a height of about 10 m on May 6, 1968, which led to the failure of the control motors.
  • Pilot Joe Algranti lost control of LLTV B1 in a gusty wind in December 1968 and operated the ejector seat shortly before impact.
  • LLTV B2 with Pilot Stu Present suffered a failure of the electrical system on January 29, 1971 and as a result the failure of the attitude control system.

The LLTV training program ended after several hundred flights with the last flight on November 13, 1972, conducted by Eugene Cernan as part of his training for Apollo 17 . The remaining two LLTVs are on display in the Dryden Flight Research Center (LLTV A2) and the Johnson Space Center (LLTV B3).

Web links

Commons : Lunar Landing Training Vehicle  - Collection of pictures, videos and audio files