The question is, is so much torque actually required for an IOM and has anybody ever done some detailed research on the sheetingloads on our boats
![Shocked :shock:](./images/smilies/icon_eek.gif)
Cheers
Moderator: Pedro Egea
A note on terminology / physics:Nigel wrote:I have been wondering about the arm winch offered by Kbits. It is based on the Jumbo sized Hitec digital servo that puts out 19kg of torque.
The question is, is so much torque actually required for an IOM and has anybody ever done some detailed research on the sheetingloads on our boats![]()
Cheers
Hi NigelNigel wrote:would something in the range of 12 Kg have enough power
<CENTER>Nigel wrote:has anybody ever done some detailed research on the sheetingloads on our boats![]()
Hi NigelNigel wrote:Do change the winch in your boat according to the weather you are expecting??
Ken and Trevor are way better sailors than I am, and their installation isn't quite the same as mine... But you need to get this from Ken. E-mail him at K.Bits, his site URL is on my "Links" page.The Binks brothers both used the arm whinch in Vancouver as far as I know and that event so a fair bit of wind at some times didn't it. How did this work for them?
Hi JohnBJohnB wrote:can that formula be used for the forces required for close haul sailing ?
Hi ReyReyNewman wrote:If you plan on using a 5735, use the programmer to slow it down - it is way too fast.
This same learning should also be applied to most any digital servo application. If one is used for the rudder servo it's important to insure the linkage is free of any binding as this will also cause the servo to drain the battery.Chairman wrote:Ken explained to me that the digital technology may need a different approach to working the sheets. In particular, he was emphatic that I really did need to take care if I wanted to use the winch to "sheet vang" -- that is, pull the main boom down at close-hauled -- and he could not recommend it. The reason is that the digital winch is controlled by a micro-processor, and this little computer is programmed to increase power to the motor if it finds the arm isn't moving to its commanded position. And it increases power and increases power until something gives. The older analogue winches can't and don't do this, they are set up to cut power as the commanded position is approached. So if for any reason your sheeting doesn't allow the winch to take up the commanded position (a sheet snag, say, or "sheet vanging" with an incorrectly-set end-point), an analogue winch will take its time about burning out, while the digital one will do so in somewhat of a hurry...
The Hitec 5735 comes with an arm that is 1inch long, from center point to end attachment point. I built a 3.75inch long arm, from center point (servo screw) to sheet pivot point, which attaches to the Hitec arm. With a 2:1 purchase, and 90deg of servo travel, I get approx. 13 inches of line travel.Tiga wrote:Hi Rey,
can you tell me: how long is the arm of your hitec-servo?
thanx
Rainer
hmm, interesting idea. A bit like the counterweight on a lift...Chairman wrote:Gyula Ferencz has told me about an old trick to increase arm winch torque to around 175% of rated amount! I'll be trying it in a couple of weeks, and here is the spreadsheet: http://www.onemetre.net/Download/Cam/Cam.htm
Hi Andersawallin wrote: ... can you measure the current the winch draws when you test this?
Yes, if anyone is thinking of trying it with a digital winch, please remember that a digital winch develops much more power than an analogue when at, or close to, its commanded position -- heat! This tensioning arrangement means that the winch must always hold its commanded position (even at close-hauled) by pulsing the motor continuously -- lots of heat! There is a very good reason why the Hitec 1/4 scale has an integral heat sink. For me, the increased current drain isn't too much a problem, but the possibility of overheating the winch would seriously spoil my day!I would assume that with this kind of system the winch works against the spring tension whenever the winch is not at its close halued position and that should lead to a higher battery drain...