Lane Change Plates for Cars with Front Mounted Servos
Posted: Tue 29. May 2018 18:22
I continue to believe that properly designed, produced, and installed plates will provide more reliable and consistent lane changes for experienced as well as newbie racers at any speed, compared to any lane change design relying only on wire. I also continue to believe that the best width of a plate is .16” (4mm) at one end and .39” (10mm) at the other, given that the diameter of the guide magnet is 4mm.
However, I now think that the best length of a plate is dependent upon the steering angle created when the operator turns the wheel on the transmitter/controller. That depends on the steering mechanism used in the car. This realization came to me after Nick Brown asked me how much steering movement I was getting with my chassis which uses an HK-5320 servo mounted between the front wheels. Martin, (aka HeliumFrog) of Magnetic Racing, uses a similar servo mounted between the front wheels.
I did more testing of the car on my track. Discovered that the car would consistently navigate a lane change to the left but would usually miss a lane change to the right. Upon examination of the car, I found that the servo arm moved farther to the left than to the right, when the servo was energized. Then I measured the steering angle created when I turned the the steering wheel to the left. It was about 8 degrees. When turned to the right it was about 4 degrees.
Using basic trigonometry, I calculated the distance between the infeed and outfeed wires needed in order to move the guide magnet 0.22” left or right, when steering angle was 8 degrees. The result of the calculation was 1.57” (40mm). For why I used 0.22” see my post on Wed 4. Jan 2017 19:12 http://magracingforum.com/viewtopic.php ... 3925#p3925
Note that Wes originally proposed a lane change plate 35mm (1.38”) long with a gap of 5mm (0.20”) between the infeed wire and plate. He suggested gaps of 2mm (0.08”) between the outfeed wires and the end of the plate. That results in a distance of 40mm (1.57”) between the ends of the infeed wire and outfeed wires which is less than the 2.20” that I receommeded. See my post on Sun 8. Jan 2017 16:06.
In the case of my track, the distance between the infeed wire and outfeed wire at the points of lane changes is usually about 2.0” Given that the calculation suggests that only 1.57” is required, I’m not surprised that my car navigates left lane changes consistently with a steering angle of 8 degrees. Note that in the case of Wes’s original car, when the steering wheel on the controller is turned left or right, a steering angle of about 15 degrees is created. With that sharp of an angle a much shorter plate, and smaller gap between infeed and outfeed wires, is needed.
I calculated the distance between the infeed and outfeed wires needed in order to move the guide magnet 0.22” left or right, when steering angle is 4 degrees. It turned out to be 3.15” (80mm). That explains why my car will usually miss right hand lane changes.
It appears to me that the minimum length required for a plate (and corresponding gap between infeed and outfeed wires) is dependent on the steering angle created when the operator turns the steering wheel. I don’t see any significant disadvantage of the plate being 10mm longer than needed.
I would like to hear from forum members who have been experimenting with a car that uses a servo mounted between the front wheels. Would also like comments from those who have been running a car sold by Martin Price of Magnetic Racing. Does the car consistently perform on left and right hand lane changes? What steering angle is created when you turn the wheel on your transmitter? Are you using lane change plates? What is the gap between infeed and outfeed wires?
I am hopeful that I will be able to design and build a chassis that uses an HK-5320 servo mounted between the front wheels which will provide a steering angle of 6 degrees both left and right. If so, such a car should work fine with plates that are 2” (51mm) long with a gap of 2.20” between the infeed and outfeed wires as I proposed Sun 8. Jan 2017. According to the calculation, 6 degrees requires at least 2.1” between infeed and outfeed wires.
However, I now think that the best length of a plate is dependent upon the steering angle created when the operator turns the wheel on the transmitter/controller. That depends on the steering mechanism used in the car. This realization came to me after Nick Brown asked me how much steering movement I was getting with my chassis which uses an HK-5320 servo mounted between the front wheels. Martin, (aka HeliumFrog) of Magnetic Racing, uses a similar servo mounted between the front wheels.
I did more testing of the car on my track. Discovered that the car would consistently navigate a lane change to the left but would usually miss a lane change to the right. Upon examination of the car, I found that the servo arm moved farther to the left than to the right, when the servo was energized. Then I measured the steering angle created when I turned the the steering wheel to the left. It was about 8 degrees. When turned to the right it was about 4 degrees.
Using basic trigonometry, I calculated the distance between the infeed and outfeed wires needed in order to move the guide magnet 0.22” left or right, when steering angle was 8 degrees. The result of the calculation was 1.57” (40mm). For why I used 0.22” see my post on Wed 4. Jan 2017 19:12 http://magracingforum.com/viewtopic.php ... 3925#p3925
Note that Wes originally proposed a lane change plate 35mm (1.38”) long with a gap of 5mm (0.20”) between the infeed wire and plate. He suggested gaps of 2mm (0.08”) between the outfeed wires and the end of the plate. That results in a distance of 40mm (1.57”) between the ends of the infeed wire and outfeed wires which is less than the 2.20” that I receommeded. See my post on Sun 8. Jan 2017 16:06.
In the case of my track, the distance between the infeed wire and outfeed wire at the points of lane changes is usually about 2.0” Given that the calculation suggests that only 1.57” is required, I’m not surprised that my car navigates left lane changes consistently with a steering angle of 8 degrees. Note that in the case of Wes’s original car, when the steering wheel on the controller is turned left or right, a steering angle of about 15 degrees is created. With that sharp of an angle a much shorter plate, and smaller gap between infeed and outfeed wires, is needed.
I calculated the distance between the infeed and outfeed wires needed in order to move the guide magnet 0.22” left or right, when steering angle is 4 degrees. It turned out to be 3.15” (80mm). That explains why my car will usually miss right hand lane changes.
It appears to me that the minimum length required for a plate (and corresponding gap between infeed and outfeed wires) is dependent on the steering angle created when the operator turns the steering wheel. I don’t see any significant disadvantage of the plate being 10mm longer than needed.
I would like to hear from forum members who have been experimenting with a car that uses a servo mounted between the front wheels. Would also like comments from those who have been running a car sold by Martin Price of Magnetic Racing. Does the car consistently perform on left and right hand lane changes? What steering angle is created when you turn the wheel on your transmitter? Are you using lane change plates? What is the gap between infeed and outfeed wires?
I am hopeful that I will be able to design and build a chassis that uses an HK-5320 servo mounted between the front wheels which will provide a steering angle of 6 degrees both left and right. If so, such a car should work fine with plates that are 2” (51mm) long with a gap of 2.20” between the infeed and outfeed wires as I proposed Sun 8. Jan 2017. According to the calculation, 6 degrees requires at least 2.1” between infeed and outfeed wires.