2002 Report

Documentation is a required part of this competition, and counts for a large part of the total score. This is a slightly modified version of the documentation we submitted to the judges.

  1. Abstract

    Fire on Ice is a remote control vehicle built for optimum acceleration and maneuverability on ice. It is designed on the premise that simplicity and excellency of design will give optimal performance.
  2. The Team

    Charley Barker is the group leader of The Team. Charley recruited Jayson Chambers, Daniel Rairigh, Leah Swanson, Fro Jean, and Jun Lee. Unfortunately Fro Jean and Jun Lee had to leave The Team before the completion of the project. All members of The Team are Sophomore Mechanical Engineering majors attending Pensacola Christian College.
    The Team would like to express special thanks to the following individuals for the excellent input and suggestions: Mr. Ron Van Puttie, Pastor Jay Chambers, Mr. Jeff Rairigh, and Mr. Tom Werkema.
  3. The Summary

    The goal of this project was to build a remote control vehicle that could maneuver on an ice rink. The vehicle would be expected to compete in a straight drag race as well as a slalom race. Given these parameters The Team developed the following priorities for its vehicle:
    • The vehicle must have excellent acceleration on ice.
    • The vehicle must have excellent traction for turning.
    • The chassis and propulsion design must be simple. ("Simplicity is the ultimate sophistication." became a team motto.)
    • To maximize acceleration the entire vehicle must be as light as possible.
    Starting with these parameters and priorities a number of designs were discussed and researched. A vehicle with tracks was suggested, but research showed that construction of powered tracks would be too time consuming. After further discussion it was decided that the vehicle should be propelled by a propeller and steered with skates. The following is documentation for each component of the vehicle.
  4. The Body

    1. Material
      Plexiglas was chosen as the primary construction material. This choice was made based on the fact that Plexiglas is light, flexible, and can be easily cut and bent. Three thickness of Plexiglas were used. The rear runner board was made of 3/8 inch Plexiglas to eliminate any flexing. This was necessary in order to guarantee that the rear runners remained exactly parallel and to allow the runner board to lie very close to the ice, both of which require that the runner not flex appreciably. Because the main chassis need not be absolutely rigid, it was built from 1/4 inch Plexiglas. Finally, 1/8 inch Plexiglas was used for the hood, simply for weight considerations.
      Smaller parts were made from aluminum, carbon steel, and PVC pipe. The bracing and the rear skate mounts are all made from angle aluminum. The front steering spindle is also machined from aluminum. Aluminum was used for all these parts in order to reduce total vehicle weight. The three skates are cut from carbon steel knife blades. Carbon steel was chosen, because it is necessary that the blades hold a sharp edge. The motor cowling is built from PVC pipe.
    2. Steering and fixed support
      A three point configuration was chosen for the suspension system. While it was suggested that four points of contact would be more stable, it was also shown that the complexities of dual steering skates would present many design complexities. It was decided that in this case the simplicity of three point suspension outweighed the loss of stability. Acceptable stability has been obtained with the three point design.
      Rear skateSingle edge skates were used for all three support points. Each skate has been ground with a large radius, which ensures a single, small contact surface between the skate and the ice on each skate. This creates maximum pressure on the ice and minimum friction. This radius also facilitates vehicle turning as noted below. The rear skates were sharpened on a single side to help increases lateral traction. The front skate was ground from both edges. Each skate was cut from a carbon steel butcher knife and re-ground for this purpose.
      Front skateSteering is provided by a single front skate. This skate is attached to a steering servo which provides radio control. The radius of the steering skate is centered to the rear of the pivot, ensuring that the point of contact on the ice will also be rear of the pivot. This ensures that the skate will return to center when steering force is released. This skate can be tilted to adjust the distance of the point of contact from the pivot. The rear skates are fixed to the chassis and exactly parallel to each other. Again the very small contact area of the rear blades allows them to remain fixed while still turning smoothly.
    3. Hood and Cowling
      The hood and cowling serve two purposes. They help enhance air flow and add aesthetic appeal. The front hood is constructed with Plexiglas sheets and is reinforced with epoxy and aluminum. The cowling around the motor is constructed from PVC pipe.
  5. The Electronics

    1. Power Supply
      The vehicle is powered by a single DC battery pack. The battery pack is made of 8 Nickel Metal Hydride cells. Each cell is 1.2 volts and rated at 800 milliamp-hours. The 8 cells are connected in series giving a total voltage of 9.6 V (1.2 V x 8 = 9.6 V) and 7.68 watt-hours (9.6 V x .8 Ah = 7.68 Wh). Two identical battery packs were constructed.
    2. Motor
      The vehicle uses one Speed 600 motor running an 11 inch propeller through a 2.3:1 gear box. According to specifications provided in the year 2000 Hobby Lobby Catalog this combination should be optimal for our battery and provide approximately 43 oz. of thrust.
    3. Radio, Servos, and Speed Control
      Vehicle control is provided through a two channel remote control radio. The radio is a HITEC Ranger 2Z. The receiver and servo are also made by HITEC. The motor is controlled by a Grand Wiring Servo GS-600 speed control rated at 30 amps. This speed control also provides regulated power from the single battery to the receiver and servo. The vehicle uses one channel and one servo to control the front skate for steering. The second channel connects to the speed control.
  6. The Conclusion

    1. Suggestions for further improvements
      In initial tests the vehicle has performed excellently. At high speeds the vehicle does have considerable steering problems. It tends to lose lateral traction and spin out. Test runs have shown that more weight in the rear corrects the problem. However, the added weight also significantly decreases acceleration. The added weight would therefore require more thrust power. There may be no way to gain optimal lateral traction while remaining within the competition specifications.
    2. Lessons learned
      The key lesson learned was the more advice and input the better. The final design of this vehicle is the result of input from the entire team as well as many outside sources. It was found that advice, especially from more experienced people, is invaluable. Many of the small details that make this vehicle perform as well as it does are the result of seeking advice from as many sources as possible.
    3. Bibliography
      There is no bibliographic information for this project.
  7. Suggestions for Future Contests

    It has already been suggested that some future contest be to the construction of a steam engine. This would be an excellent competition, and would involve many aspects that previous competitions have not addressed. However, it could potentially become much too complex. Rules for the competition would have to be carefully thought out to help allow the engine to be simple enough to be completed by students in one year.
    Members of The Team have also made the following suggestions for next years competition:
    • Potato gun, range and accuracy competition.
    • Demolition derby / Battle Bots