Finding the Max Force from the Piston 

Important measurements:

• Piston:

• Using calipers, we measured

  • 0.755in from retracted piston to outside hole

  • .30in of thread

  • .455in height inside of Piston where bp explodes

• From McMaster, the pistons have stated forces from certain Pressures. We used that to find the internal radius/diameter of the piston

  • from F/A=P → 90/A=100 A=0.9 D=1.07

• Using these numbers, we then calculated the volume of the internal piston: Volume=0.409

• This could be better optimized by instead filling the inside of piston with water and measuring the water mass.

• Black Powder Capsule

• Radius 0.185in

• Height: 0.489in

• Volume=.052

Black Powder(BP) Calc Link: https://www.insanerocketry.com/blackpowder.html 

Calculation in above link:

We are using four 6-32 shear pins which have an estimated force of 240lb. To have a 2x safety factor, we want enough black powder to break more than 480lbs of force.

• D of bp area=1.07in

• L of bp tube=0.51in

  • This number was made by keeping the radius/diameter of the piston that the force will be applied to the same while adding more height to account for extra volume added from the black powder capsule.

• Testing different black powder amounts, we found that 0.15g generates a calculated Piston Force of 570lbs = 2535.49 N