History

The Marquardt R-4D rocket engine was developed for use on the Apollo Service Module, Lunar Module for attitude control and velocity change maneuvers. The R-4D is a small hypergolic rocket engine. Utilizing as propellants Monomethylhydrazine  (MMH) & Nitrogen Tetroxide (NTO). Propellant valving is provided by two normally closed, twin coil, solenoid actuated, coaxial flow, poppet-type valves, with integral propellant flow regulation orifices and inlets. The integral fixed orifices are incorporated into each valve to provide the correct propellant pressure drops at the design inlet pressure to required thrust level. The combustion chamber is fuel film cooled molybdenum with molybdenum disilicide coating which allows it to reliably operate at sustained temperatures of 2000 Degrees F. The Apollo RCS (Reaction Control System) thruster played a critical role in the success of NASA’s Apollo program. This small but powerful engine was responsible for controlling the attitude and movement of the spacecraft during critical phases of the mission, including docking, rendezvous, and lunar landing. Unlike the main engines of the Apollo spacecraft, which were used primarily for course corrections and to achieve orbit, the RCS thrusters were used for fine control and adjustments.The RCS system consisted of 16 thrusters, each with a thrust level of 100 pounds, distributed around the spacecraft. The thrusters were arranged in groups of four, with each group oriented in a different direction: forward, backward, left, right, up, and down. This allowed the spacecraft to be maneuvered in any direction, making it possible to dock with the lunar module, perform mid-course corrections, and make small adjustments during the descent to the lunar surface.One of the key advantages of the RCS thruster was its reliability. During the Apollo program, the RCS system was used on every manned mission, and it proved to be extremely dependable, even in the harsh environment of space. The thrusters were also very precise, allowing the astronauts to make very small adjustments to the spacecraft’s attitude and movement.

Specifications:
Thrust: 100 pounds (440 N)
Dry weight: 3.63 kg (8.00 lb)
Fuel: Monomethyl Hydrazine (MMH) & Nitrogen Tetroxide (NTO)
Length: 13.66 inches (347 mm)
Diameter: 5.9 inches (150 mm)

What’s in the box:

1x Full SLA (Stereolithography) 3dprinted scale model kit with very high detail.

1x Printed assembly manual.

1x Painting and Marking guide with color conversion chart for most popular color brands.

1x High quality waterslide decals plus metalic foil for decals.

*Kit comes in an OEM cardboard box (NO graphics).

Dimensions of finished model:

Height: 347mm (13.6 in)

Diameter: 150mm (5.9 in)