So the distance vs disc speed thread got me thinking... If there is this kind of info out there, what other studies have been done in regards to the aerodynamics of disc golf and frisbees. Well, a little internet searching turned up some interesting reading... As part of a master's thesis for mechanical engineering, Sarah Hummel (possibly my future wife, but thats another thread...) introduces a detailed explanation on frisbee flight.
Some of the info can be a little difficult without a background in engineering or physics and anatomy and physiology, but it is insightful nonetheless. (Wikipedia should be useful to fill in the gaps if needed). I will point out some of the noteworthy segments:
- Sect 2.2.3:
Drag force is minimum when lift is zero. This happens when angle of attack is about -4deg. (The disc's nose is turned downward 4deg with respect to the direction of flight)
- Sect 2.2.6
The lift force would make sense to be greater to the left of the midline than to the right, so discs should have a positive roll moment and turnover naturally. Not the case, explaining why they fade out at the end.
- Sect 2.2.6, 2.3
At low spin rates, the left-to-right force is negligible, so they are neglected from the EoM. Spin plays a bigger factor in providing stability during flight (makes sense)
- Sect. 2.3.2
OAT is caused by angular velocities introduced about the x- and y-axes.
OAT dampens during the throw, bc disc throws are not torque free motion. The torque is caused by the COP not being coincident with the COM.
Positive roll moment causes the nose to dive. (Turnover shots typically finish nose down) Negative roll moments cause the nose to lift. (hyzers flare up)
- Sect 2.4.2
Nose down flight with positive angle of attack gives flight with where lift force equals gravity.
- Sect 2.4.3
The fade at the end of the discs flight is caused by the increase in pitching moment during flight. This increase is caused by the decrease in velocity caused by drag and gravity.
- Sect 2.5
Disc design to produce desired flight....
- Chap.3
Mathematical models to produce data for frisbee flights
- Sect 4.1-4.3
Modeling the body during backhand throw. (Blah, blah, blah...)
- Sect 4.4.1-4.4.2
Body motion troughout the throw.
- Sect 4.4.3
All your power comes from the body, not your arm (Work on your form!!!). Most of the energy comes right before, not at the release of the disc.
Most of the energy imparted into the disc goes into the translational not angular velocity of the disc
- Sect 4.5 (Specifiically 2nd paragraph)
Increasing wrist snap doesn't do much for increasing energy to disc. Instead the most power comes from shoulder abduction, increased torque and rotation is translated through the kinematic chain to the wrist snap.
If only the idea for my thesis didn't just get thrown out the window....