Piston Test
Goals:
Validate the manufacturing and integration of our hardware components
Validate drogue bag design and proper drogue deployment
Materials:
Black powder (.2 g per firebolt)
Piston
Cup
Diaphragm
Firebolts
Piston fittings
Airframe
Anti-rotation rod
Drogue parachute
Drogue bag
Rope guide
Piston Mount (sustainer assembly only)
Necessary screws
x8 6-32 set screws
x2 8-32 cap screws
Hex keys
Phillips head screwdriver
Gloves
Weighboats and popsicle sticks
Teflon tape
Safety glasses
Close toed shoes
A very long wire, alligator clips, and possibly a battery
Scale
Check-offs:
Make sure black powder handlers have Employee Possessor licenses
Fit check
Reserve the blast chamber/field
If doing test outside, alert the police beforehand
Piston Integration Procedures:
Using a 1/4 inch torque wrench, ensure that the bolts holding the piston together are tight (100 inch-pounds of torque). If the bolts are loose, the piston will lose pressure as it extends. (torque wrench adapter in piston box)
Integrate Firebolt into NPT Plug
Use multimeter to check continuity of Firebolt (should be about 1.0-1.4 ohms) and twist the wires to short it. Two people should visually confirm that it is shorted.
Wrap the Firebolt with five wraps of Teflon tape.
Use the 7/16 wrench to screw firebolt into the NPT plug as far as possible. Highly recommend using the threaded brass plugs since it is threaded all the way.
Repeat steps a through c for a second firebolt and plug
Integrate black powder
Everyone put on safety glasses. From now on, everyone within the vicinity of the pyrotechnics must wear safety glasses.
Measure out 0.2 g of black powder and pour it into the other side of the plug, holding over a weigh boat to catch any fallout. This should be close to filling the plug and may overflow slightly if you screwed the firebolts all the way in.
Seal the opening by wrapping over the head and opening three times with Teflon tape. Make sure Teflon tape is flush on the inside.
Repeat steps a through c for a second fully integrated plug
Screw a fully integrated plug into the left side of the tee fitting (relative to the tee fitting orientated like a "T"). Tap the tee fitting several times and make sure no black powder falls out after screwing in the plug. If any black powder falls out, remove the plug and repeat the integration of black powder.
Repeat step (4) for the second fully integrated plug, but screw it into the bottom side of the tee fitting (again relative to the tee fitting orientated like a "T")
Compress the piston completely!
Screw an elbow joint into a side female end of the tee after adding Teflon tape. Tighten it until it is reasonably secure but make sure it can still be tightened a half rotation.
Screw the entire fitting assembly into the piston NPT hole. Make sure that the fitting assembly is pointed up (in the direction of the bore) and rotate tee fitting until the side plug is as close to the body of the piston as possible.
Screw anti rotation plate into the top of piston using the short 1/4-20 screws
Slide diaphragm on (lip facing up), with anti rotation rod attached and slid through hole of anti rotation rod holder.
Test the piston by pulling up rod for 5 secs and checking that it is sealed
Log Firebolts
Integrate into airframe
Piston Testing Procedures:
Perform integration according to the Piston Integration Procedures above.
Run wires from outside to inside the blast chamber. Make sure that the wires are shorted on the outside of the blast chamber. On the inside, unshort the e-match leads and connect it to the wires.
Clamp the airframe between two bricks.
Only after exiting the chamber and closing the door, perform a countdown and connect the outside wires to a voltage source.
NOTE: If testing on field, the airframe should be oriented horizontally. Make sure to establish a 25 feet testing distance
In the event of a misfire, disconnect the battery and wait at least 60 seconds before allowing anyone to enter the chamber/approach the test article.