Sustainer - Piston Mount

Purpose:

The piston mount braces the piston against the airframe.

Requirements:

• Must withstand the force applied by the piston (60 lbs/bolt, 360 lbs total) [with minimal deformation, less than .1 mm]

• Must fit within the airframe

• Must be able to interface with mission package tube and structures below

• Must be able to interface with piston

Details

Material: Aluminum 6061 T6

Mass (from CAD model): 0.05 lbs

Safety Factor: 2.2

Design

Design Brief:

This part is an optimized version of the piston mount from the sustainer of the Staging Demonstrator. The objective in designing this part was to reduce the mass of the original piston mount without adding substantial complexity to the machining process. The piston mount has six 8-32 tapped radial holes to interface with the airframe. It has six 1/4-20 holes along the surface to interface with the piston superstructure. It has one 5/8-18 tapped hole in the center to interface with the piston.  The original piston mount included a ring on the end connecting the spokes; this was removed in order to save mass. According to FEA analysis, the walls around the 1/4-20 holes were thickened so that the part can withstand the force applied by the piston. 

Manufacturing

Plan

1. Waterjet profile
   1. Leave holes slightly undersized
      
   2. Leave outer diameter slightly oversized
2. Clean up holes on the drill press
   
3. Tap center hole and six surrounding holes
4. Use piston as a fixture to turn outer diameter to final size
5. Use piston as a fixture to drill and tap holes on the indexer

TBD - waiting to return to campus

Testing

Ground Test