----- Original Message ----- From: "Michael Lachowski" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Friday, October 01, 2004 7:28 AM Subject: Re: [RCSE] Contests, Landings, etc.
> The correct way to limit launches is on the motor side, not on the > line side. Broken lines just slow down contests and make everyone > unhappy. > I agree with Michael. The motor side is the place to limit pull on the winch line, if that is what is desired. There is a simple technique that I have heard has been tried with some success in the past. It involves mounting the winch on a spring loaded pivoting device that electrically limits the force on the line. A microswitch interrupts the circuit between the foot switch and solenoid when the pull on the winch line moves the winch on the pivot against the pull of the spring (the weight of the winch itself is also involved). This cuts power to the winch motor until the line tension lightens enough to allow the spring to pull the winch off of the switch. The spring is adjusted against the pull on the line using a simple spring scale such as is used to set up highstarts to set the trip point. If you just stand on the pedal, the result is a near constant force pulsing of the winch line throughout the launch. Actually the pull slightly declines as the diameter of the stack of line on the drum increases with line taken in. This scheme works without breaking of the line or releasing the model early. This is 1920's technology, but effective. A more expensive technique using strain gauges and electronic motor speed controls could be devised. 8^) I am sure that with proper launch technique, towering launches can still be achieved with such a system set at 80 pounds pull launching 4 pound models. I suspect that experimentation will show that 20 to 30 pounds will be more than adequate. Tim RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
