“Well if the chutes don’t open, what’s the point?”
---- Ken Mattingly, Apollo 13
Making chutes can either be one of the quickest or longest phases of making a rocket, depending on the complexity. To compete in the Advanced Category of IREC (as of Aug. 2016), making a chute is required. Below we detail how the chutes, deployment bag, and risers for Therion were made.
Kelly! Zach! Help!
Planning geometry
Many different geometries for parachutes can be used, such as a semi-ellipsoidal geometry, which was the geometry used for IREC 2016. Any cross section of a semi-ellipsoidal (often just referred to as ellipsoidal) parachute is half of an ellipse, and the entire surface is defined by rotating one side of that ellipse around it's central axis. The general procedure for defining the size and shape of the gores for a body of rotation (as applied to creating a semi-ellipsoidal parachute) is as follows:
- Determine the equation of the curve that defines the body of rotation; in the case of a semi-ellipsoidal chute, the equation is $ \Large{ \frac{x^2}{r^2} + \frac{y^2}{h^2} = 1} $, where $$ \large {r}$$ is the desired opening radius of the inflated parachute and $$ \large {h}$$ is the desired height of the inflated parachute
- Find the arc length of the curve by using the arc length forumula:
Cutting the gores
Assembling the gores
#somanyshroudlines
Deployment Bag for Parafoil
Risers
The risers were made of 1” REI climbing rope, rated to 22 kN. The ends were sewn in a “box and X” pattern as shown, leaving a small loop for the quicklink to attach to.
Shielding
Something about Nomex shielding…