Handmade Balsa

Posted in Crankbaits by admin on August 12, 2009

We are building cars of model physics using gears. It must pass a speed test and a test-firing weight. Any?

We have a ton of gear (15, 45 and 75 teeth), and a motor powered by a 9V battery. We have to make a minimum speed, and pull a minimum weight. At present we can not even get it to put itself. = (Any ideas? My brother has suggested a transmission Asset dragging around axles, anyone know how I would do that? Finally, we also, when we decorate the car, have to add functionality (Sunroof, headlights, side mirrors, etc etc) Anyone have any cool features would be cool to have, but it would be easy to put on a model car? (Keep in mind that this is a car model from styrofoam or balsa wood, not plastic, and everything would be done manually, or something easy to find at home) Thanks!

To start a little terminology. The train as small number of teeth that is attached to the engine is called the pinion. The gear will be called more gears. Velocity-ratio is expressed in number of turns of the pinion (Or orders) by single lap of the driven gear. For example, assuming that the train is the 15 tooth sprocket and the driving gear 45 teeth with it, the gear ratio will be 3 to 1 (obtained by dividing the number of teeth on the right wheel by the number on the pinion). A ratio of speed of 3 to 1 multiplied by the torque of the engine 3 (ignoring friction losses). To understand why this works can watch the work formula, Work = Force x distance. Increase the distance of travel gear (adding teeth in the cycle) reduces the power required for a given amount of work. Or the thought of another way for a given torque (force rotation of the engine) to triple the distance the force acts on, triple the torque to the wheels straight axle and what work can be done (even ignoring friction). This is a good thing because your engine is low-end torque, but moves very quickly. Make the pinion travel a long distance to rotate the spur trades that speed reducer for more torque. I assume you've tried the gear teeth 75 driven by the motor pinion and it still did not enough power to move the car. In this case, you'll need to gear system compounds. To do this, you will need two gables and two axles. Attach a 45 tooth sprocket and 15 teeth of an axle and mount the engine so it is the drive pinion gear 45 teeth. Then mount the second axis (it will have wheels on it) with a gear 75 teeth on it so it is driven by the sprocket on the front axle. This will give you a couple approxamately as a product of two gears 3 to (45/15) and 5-1 (75/15) or a ratio of 15 to one. This should move the minimum weight easily, but perhaps too slow to minimum speed. If this is the case, try to replace the 75 tooth gear with another gear 45 teeth giving a final ratio of 9 to 1. I hope this helps you get a good note and hopfully learn something useful. Also a little more detail on what you've tried so far could help me find more specific suggestions. As in the decorations would you do headers style zoom Macaroni?