Brian, Thanks, I assumed digital servos in my post, but didn't think that some might not be aware of this.
A little more background for anyone interested: The initial reason for the development of digital servo programmers was driven by the needs of the guys who fly the big aerobatic planes, sorry, not sailplane flyers. I fly power also, as well as electrics. Dave Garwood calls it cross dressing, I am not sure I like the connotation, but then I call him a slopehead. When these TOC pilots started ganging up digital servos on large 40% size models they quickly found out that digital servos center a slight amount differently from servo to servo. Because there resolution is more precise than analog servos, they (when ganged together, up to 5 servos on a 40% rudder) constantly fought each other for center. This caused significant current drain. Coupled with the fact that linkage variations are magnified, and that digital servos produce 100% of their torque with 1 degree of offset it was a problem. In the beginning the pilots had to buy 10 digital servos and try to match 4-5 that centered similarly together, and then use the others on other single servo applications. Well if you are talking a JR 8411, that's $1100.00 to get four servos that work together. Hence, for the price of one servo the three companies came out with a programming device to give pilots the ability to program neutral points, but also included end points, speed, and depending on the brand, other functions. This opened up many other applications for the rest of us. JR and Futaba came up with a device that rides in the aircraft. The JR Matchbox not only allows servo synchronization, it allows a flyer to plug in 4 servos, a dedicated battery pack, and use one channel to "program" or synchronize up to four servos. (Jet pilots loved this concept as well). Great for 8 channel radio owners to expand their possibilities without buying a new radio. Example: divided flaps on a large scale ship. With the Matchbox, the R&D dept also found that you can use one channel to switch up to 3 on off functions using a slider or three position switch. So if you fly a scale sailplane with opening canopy, or another on off function, you can do it without a super radio or extra channels. You do not have to have digital servos for this application. Hitec in their approach came out with a programmer that is a bench tool, good for syncing and programming digi servos of their brand, but not having the features of the JR matchbox, and presumably the Futaba, which looks like a clone of the Matchbox. I have not "tested" that one. Jr also makes a nifty device called a channel expander. This device can sequence and switch (not proportional) up to four servos with a dedicated battery pack. It allows more switching flexibility but will not program digi servos. These devices are all brand specific. John Derstine Endless Mountain Models http://www.scalesoaring.net email: [EMAIL PROTECTED] -----Original Message----- From: Brian Chan [mailto:[EMAIL PROTECTED] Sent: Sunday, October 26, 2003 1:49 AM To: John Derstine; 'Jay Decker'; [EMAIL PROTECTED] Subject: RE: [RCSE] Hitec HFP-10 Digital Servo Programmer? Only work with DIGITAL SERVOS for servo reprogramming. Does not work with analog servos. Brian -- Brian Chan An Electric Airplane [EMAIL PROTECTED] Mateo.Ca.USA 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.
