The second approach was accepted.
Manufacturing, Assembly, and Implementation of Selected Design
During preliminary testing, it was determined that the main engineering problems would be: (1) limiting the force of the mechanism, and (2) determining the best way to attach an appropriate weight so that the release point would allow energy to be converted into forward propulsion as efficiently as possible. In that regard, string with attached metal hooks was used to hold back the trapping bar at the halfway position and a slipknot was used to permit the activation and release of the bar. A small piece of tin was added to the middle of the horizontal segment of the trapping bar and positioned at an appropriate angle to launch a small weight backwards.
Testing, Evaluation, and Conclusion
Testing the selected design revealed the importance of limiting the energy and speed of the trapping bar, mainly to launch the weight backwards instead of upward, but also to limit the shock transmitted to the entire device.
To further stabilize the device, a weight was also attached to under surface with sufficient ground clearance not to interfere with movement. Notches were cut into the to rear corners of the device and string looped across underneath, emerging from each side; the two sides of the string were tied together to a loop in a small hook used to hold the trapping bar under tension at the vertical position. The bar was released by gently pulling a slipknot holding back the hook. By testing different weights in the tin release platform, the experimenter was able to achieve reasonable consistency of the release point. Ultimately, the device proved that the principle of propulsion was valid but incapable of producing sufficient propulsion to traverse.