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Badger performance w/ outboard well & Belcher windvane steering

  • 05 Dec 2013 17:44
    Quote
    Reply # 1452362 on 1431262
    Anonymous member
    Looking thorugh Bill Belcher's book, I see that he mentions a 3:1 linkage ratio at one point, but in his design for a complete pendulum gear, he has a linkage ratio of 2:1 which is better. I use a linkage ratio of 1.5:1 on my gear. That is, the drum at the vane has a radius of 80mm and the tiller on the servos is 120mm long. To use such a small ratio, the vane has to be bigger, but the steering is much more positive. Also, there needs to be plenty of negative feedback built in to the system, to avoid oversteer. 

    With a pendulum servo gear, you bias the pendulum when there is a requirement for a lot of weather helm, by shortening the line on the weather side of the tiller and slackening the lee side line; then the blade stays more vertical in the water, and the vane stays more upright. With a trim tab gear, you can't do that. Also, with a trim tab, the tab is working against the rudder, not with it, so more rudder angle is needed, so more tab angle is needed, so more vane angle is needed. This results in poor course keeping. These two things are why I ditched the trim tab on Tystie and went to the more complex servo pendulum system.

    I'm wondering whether your servo blade or trim tab (which is it?) is big enough, if the vane lies flat but there is not enough steering force being generated.
  • 05 Dec 2013 13:23
    Quote
    Reply # 1452197 on 1431262
    Deleted user
    Well, the vane is repaired, but doesn't work on a broad reach, nor downwind. 
    Looks like it needs to hit full horizontal position to turn the trim tab enough to react against the weather helm. But if Ashiki is heeled over, the vane can never be passed horizontal, so the rudder can't correct and she heads up.
    I've tried attaching more counter weight, to no avail, looks like I need to alter the linkage ratios. What a pain. Anyone been through this?
  • 14 Nov 2013 06:10
    Quote
    Reply # 1438036 on 1437729
    Anonymous member
    David Tyler wrote:Yes, I just leave my vane free, but coupled to the servos, which damps the motion, and don't even try to leave it head to wind.
    I do likewise and leave the tiller attached to the ss in order to stop the rudder thrashing about.  I usually leave the wind vane athwartships, in fact, so that it usually lies flat on its back when I'm at anchor.  It makes much less noise that way.
  • 13 Nov 2013 23:23
    Quote
    Reply # 1437729 on 1437689
    Anonymous member
    Gary King wrote:
    David Tyler wrote:Both Bill Belcher's vane and mine have a drum at the vane axis, and cord linkage to the servo. Mine will lie down almost to horizontal, when not in use, and has never shown any tendency to self-destruct (this is a distinct advantage over vane gears that have push/pull rods and cranks). What's different about the Belcher vane that it won't spill the wind by lying down?
    Can see it lying flat in this pic. I had left it lashed this way when we found it broken after an afternoon of gale force winds. The vane beat itself up banging up and down against the lashing, though there wasn't much slack in the line as I had re-tied it that day. Are you saying leaving the vane free would have saved it? It did have a tendency to bounce from the end of its arc.
    Confucius, he say: "The reed that bends in the wind does not break". Yes, I just leave my vane free, but coupled to the servos, which damps the motion, and don't even try to leave it head to wind.
  • 13 Nov 2013 22:34
    Quote
    Reply # 1437692 on 1437017
    Deleted user
    Arne Kverneland wrote:

    Stavanger, Wednesday

     

    David Thatcher’s method of «undressing» the vane, when not in use, is clever. It reminds me of the Dutch windmills, which had the wings dressed with canvas before use.

     

    My tactics was to make the vane easy to fit and remove. Now I was up in my attic and took a couple of photos:

    This photo shows the lower part of the vane. The main horizontal shaft is just a long brass rod, held in place with a string. To make the control lines from the vane easy to fit, I terminated them in two aluminium hooks, which are easy to clip onto screws on the main pulley. Together these mods made it easy to remove the vane after each trip (I used it a lot for daysailing, the last 2 years of my BM rig days). Fitting it was no harder than setting the flag.

     

    Cheers, Arne

     

    PS: Unlike in Belcher’s plans, I mainly “welded” all the bits of the OGT together with West Epoxy.

    I'll make an admission, I already ripped off your brass rod idea, mine is held by a galv rod :)
    Still have that part of the vane (pulley, ply pivots - the fiddly bits to make), just need to bodge on, ok.. epoxy "weld",  a ply sheet.
  • 13 Nov 2013 22:29
    Quote
    Reply # 1437689 on 1437656
    Deleted user
    David Tyler wrote:Both Bill Belcher's vane and mine have a drum at the vane axis, and cord linkage to the servo. Mine will lie down almost to horizontal, when not in use, and has never shown any tendency to self-destruct (this is a distinct advantage over vane gears that have push/pull rods and cranks). What's different about the Belcher vane that it won't spill the wind by lying down?
    Can see it lying flat in this pic. I had left it lashed this way when we found it broken after an afternoon of gale force winds. The vane beat itself up banging up and down against the lashing, though there wasn't much slack in the line as I had re-tied it that day. Are you saying leaving the vane free would have saved it? It did have a tendency to bounce from the end of its arc.
  • 13 Nov 2013 22:16
    Quote
    Reply # 1437680 on 1437656
    Anonymous member (Administrator)
    David Tyler wrote:Both Bill Belcher's vane and mine have a drum at the vane axis, and cord linkage to the servo. Mine will lie down almost to horizontal, when not in use, and has never shown any tendency to self-destruct (this is a distinct advantage over vane gears that have push/pull rods and cranks). What's different about the Belcher vane that it won't spill the wind by lying down?


    My OGT, "Otto" certainly  would lie down  -  I rather took it inside to protect its varnish...

    Arne
  • 13 Nov 2013 21:45
    Quote
    Reply # 1437656 on 1431262
    Anonymous member
    Both Bill Belcher's vane and mine have a drum at the vane axis, and cord linkage to the servo. Mine will lie down almost to horizontal, when not in use, and has never shown any tendency to self-destruct (this is a distinct advantage over vane gears that have push/pull rods and cranks). What's different about the Belcher vane that it won't spill the wind by lying down?
  • 13 Nov 2013 10:15
    Quote
    Reply # 1437017 on 1431262
    Anonymous member (Administrator)

    Stavanger, Wednesday

     

    David Thatcher’s method of «undressing» the vane, when not in use, is clever. It reminds me of the Dutch windmills, which had the wings dressed with canvas before use.

     

    My tactics was to make the vane easy to fit and remove. Now I was up in my attic and took a couple of photos:

    This photo shows the lower part of the vane. The main horizontal shaft is just a long brass rod, held in place with a string. To make the control lines from the vane easy to fit, I terminated them in two aluminium hooks, which are easy to clip onto screws on the main pulley. Together these mods made it easy to remove the vane after each trip (I used it a lot for daysailing, the last 2 years of my BM rig days). Fitting it was no harder than setting the flag.

     

    Cheers, Arne

     

    PS: Unlike in Belcher’s plans, I mainly “welded” all the bits of the OGT together with West Epoxy.

    Last modified: 17 Feb 2015 19:36 | Anonymous member (Administrator)
  • 13 Nov 2013 08:44
    Quote
    Reply # 1434143 on 1433635
    Deleted user
    David Thatcher wrote:
    I also have a Belcher type vane. I was having issues with damage to the vane from wind. As a solution I have cut most of the plywood out leaving a great hole in the middle of the vane but strengthened up the trailing edge with a bit of 12mm alloy tube glassed on. 
    Thats a good one, I'll leap on that idea, tks.
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