Mechanical Design of the LMDE.pdf - Heroicrelics

Engine DescriptionCOMffNSAT1NGSPItiNGFigure 2.The LMDE is a compact packageweighing 394 lbs and having overalldimensions of 90-1/2 inches by 59 inchesdiameter. Interface with the LunarModule vehicle is made at two trunnionsthrough the gimbal frame, providingcapability of gimballing 6° in bothlateral directions (Figure 2). Propellantsare supplied to the LMDEthrough two stainless steel propellantinlet lines with a simple bolted flangeinterface joint. The inlet linesaccommodate the 6° of gimbal motion bymeans of a pair of flexible bellowswelded in the lines at their intersectionwith the gimbal axes. Propellantsflow from the lines throughthe cavitating venturi flow controlvalves to the quad-redundant ball shutoffvalves. From the shutoff valve,the fuel enters the manifold of thehead end. The major percentage ofthe fuel is injected axially into thecombustion chamber through the annularorifice of the variable area concentricinjector, while the remainder is distributedto the 36 ports of the barriercooling ring where it is injected alongthe wall of the chamber. The oxidizerenters the center of the injectorassembly, flows down and is directedinto the combustion chamber radiallythrough the variable area ports in ahorizontal disc composed of 36 jetswhich impinge on and ignite with thesheet of fuel.Figure 3.I flOW"'''LYE.!l!!!Thrust Control AssemblyThrust control is accomplishedby adjusting the propellant flow ratesand varying the area of the injectionports to maintain near uniform velocities.Electrical control signals fromthe Lunar Module are received by theelectromechanical throttle actuatorwhich converts the signal to a linearposition of the actuator screw jack(Figure 3). Attached to the top ofthe screw jack is a cross beam. Theright side of the cross beam is connecteddirectly to the oxidizer flowcontrol valve through a flexural element.The left side of the cross beam- 2 -