[:-banghead] Steering systems would be one of the most critical and time consuming challenges of the design and build of a R/C land yacht.
Having said that, they can be great fun and most satisfing to design and make.
I am currently up to Mark IV in my development of the ultimate cool design.[:-clown]
I will try to provide a link to some photo`s of steering systems.[-crzwom]
Do it NOW before it`s too late.http://nz.msnusers.com/SharedPicturesIanHB/landyachts1.msnw
Hmmmm - now if that was carbon fiber or … [:D][:D][:D]
Ian,
Your design looks like it should work fine. In fact it looks a bit like mine in that it ignores the standard rules about caster, so any lateral pressure from the sail rig will exert a torque, causing the servo to work more than a more “neutral” arrangement. The importance of a balanced design becomes even more paramount. One thing I like about this concept is that it will help you get unstuck from a stall. The reason being that when you wiggle the servo, the motion will often “break loose” the static friction when at a dead stop.
My only suggestion would be to consider introducing a slight offset at the cable attachment points, or at the servo horn. This will allow the nonworking cable to slacken a bit, which will avoid too much tension in the sytem. This has to do with the geometry of converting rotary motion into lineal motion:
http://members.cox.net/bdfelice/Ackerman/ackerman.htm
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>My only suggestion would be to consider introducing a slight offset at the cable attachment points, or at the servo horn. This will allow the nonworking cable to slacken a bit, which will avoid too much tension in the sytem. <hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Bill could you please explain what you mean ?
Stephen,
Sorry, I thought the URL would explain what I meant. Basically, it would involve shifting the cable connections forward a bit(about 3/32")so they’re no longer in straight alignment with the steering gear pivot. The same effect could be derived from shifting the servo horn attachments, although this would involve fabricating a non standard horn. All of this is called rotary-lineal differential. When any sort of (non circular) lever arm moves, the maximum linear motion happens when the arm is at 90 degrees, then diminishes to zero when the arm reaches 180 degrees. The common example is a crankshaft & piston on an internal combustion engine, or steam locomotive drive wheels. It is mathematically described by a cosine curve.
The idea is to avoid having the cables be tensioned too tightly, but yet function reliably. Ian’s setup will indeed work; this suggestion is simply “tweaking” to help it work a bit better. The thing to absolutely avoid is to have an offset in the “wrong” direction, as this would cause the cables to become progressively tighter as the steering angle increases. I hope this helps clarify what I was saying.
Bill
US 66
Firstly good to see more Kiwi interest. This steering works real well and you’ve made a real solid looking version by the looks of it.
The main drawback is that if crash head on you’ll likely strip the servo unless you have a servo saver installed. Secondly if your servo is not strong enough you will suffer from steering issues when overpowered. Though it does turn super fast making for very high speed tacks.
I also had this steering setup as my first and because of the high drain from the sheet servo and issues with the BEC of my AM RX unit I mistook it for a pure steering issue. In the end I opted for a standard front fork setup and glad for it as I’m still using it after a few crashes before I sorted out the issues with my RX.
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by NZGene
I also had this steering setup as my first and because of the high drain from the sheet servo and issues with the BEC of my AM RX unit I mistook it for a pure steering issue. <hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Hey Gene, glad to hear the problems weren’t caused by the design concept [:D][:D] I remember you mentioned the issue on the yahoo forum, but I didn’t think the steering geometry was causing it, because I never had similar problems with mine.
BTW, I’ll be taken a couple of my iceboat models down to “Kites on Ice” http://www.madisonfestivals.com/kites/index.php
this weekend. It’s a big event drawing thousands of spectators & kiters from across the US & worldwide. Winds are predicted to be breezy, so I’m sure they will generate some interest.[:-jump2][:-jump2]
Bill
Kite+snowboard= NO GOOD
-Wis
_/ if it isn’t broken, don’t fix it! _
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by wismerhell
Bill
Kite+snowboard= NO GOOD
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Yeah, it’s a good way to break some bones. This year they’ve plowed snow onto big piles to give these practioners of an “extreme” sport an extra “oomph” to their launch.
BTW, my brother-in-law Steve Green lived in Japan for several years teaching English, married beautiful Japanese woman. They’re both back in the States now, going to grad school.
a bit same here…the marriage thing …work as well though
-Wis
_/ if it isn’t broken, don’t fix it! _
Bill:- Yeah, the extra battery pack on a y-harness for the large sailarm servo solved the intermittent steering issue completely. Though stripped two steering servo’s due to crashes on that steering configuration. The new one survived a 2m fall off a water reservoir [:-boggled] and a bounce off a tree [B)] so I’m happy with that.
Kites and snowboards rock! The fastest I think I’ve ever gone with a kite, racing cars up the road next to the field doing over 70kph and passing them. Best way to make good use a golfcourse in winter too. [:D] Though I’d stay away from ice unless I can swap a snowboard for skiis or an icebuggy. Water can be just as bad… says me walking on a bad knee after getting too cocky in head high surf last Saturday.
talking kites [:)]
hmm did all…Buggying, surfing and jumping…all with my Blade (made by Flexifoil)…too bad I cant use it here [:(]…I did tried with the snowboard…but NEVER again!! maybe I should try skis [:p]
-Wis
_/ if it isn’t broken, don’t fix it! _
Same…still do. Blades are good for buggying but I don’t rate them for boardsports simply because they’re too reactive in a gust. Sleds or Arcs give heaps more stability and smoother hangtime. Gotta be comfortable on a snowboard to use one with a kite. If skiis are your forte better stick to them at least for the sake of your tailbone [:-bigeyes]
Now is probably a good time to mention that I’ve been playing around with converting a little ram-air foil as a sail-wing for my RC landyacht. Struggling a little with the rigging and ‘tacking’ the negative camber in the trailing edge. But it should be fast… very fast. The kites that I’ve based my wing on are capable of doing 200kph in the air with tons of grunt. Will see how it goes…
oops, sorry, post was afu
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by Bill Korsgard
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by NZGene
Now is probably a good time to mention that I’ve been playing around with converting a little ram-air foil as a sail-wing for my RC landyacht. Struggling a little with the rigging and ‘tacking’ the negative camber in the trailing edge. But it should be fast… very fast. The kites that I’ve based my wing on are capable of doing 200kph in the air with tons of grunt. Will see how it goes…
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Well, that’s a topic for a whole other thread, but I would be VERY interested to see what you come up with. Sort of reminds me of what Dean Kaseler did when he worked for Naish sails in Hawaii: http://olypen.com/dkaseler/inflatable.htm
His "Wide Sock sail holds the world speed record
http://olypen.com/dkaseler/home.htm
[:-bigeyes][:-bigeyes][:-bigeyes]
to be honest, I ve always wanted to build something rc with a powerkite…but no idea how to control the thing…my idea was a hull like a surf…plus the powerkite…just hot air…as I have no idea on how to make it work
-Wis
_/ if it isn’t broken, don’t fix it! _
Unfortunately I have only ever seen prop powered RC gliders. Though I was toying with a more crashfriendly ram-air ridge soarer design before builing a landyacht instead.
Here is a link to an Italian web site with a very good artical on steering systems. Check it out. [:-bigeyes]
http://www.carriavela-rc.com/articledetails.jsp?id=1
Do it NOW before it`s too late.
Great !!! [:-banghead]
Now my secret is out - darn… and everyone will have one. Thanks Ian ! [:D]
Actually, the kite control issue is what would be interesting to see. We kicked kites around in the F-48 Class when writing rules, but too many current rules have an effect on kites touching, starting, finishing, etc. that we decided to take a wait and see attitude. Currently they are not approved for the class - but when ISAF comes up with “modern” rules, we can look at the rule again.
I see kites as an exciting idea - but not for racing at this time, since like boats - many rules do not take into account the kite is attached by lines, but could be more than 5-6 yacht lengths away from the actual land yacht.
As in the F-48 Class - lets say one rounds the weather mark and finish is downwind. Jut keep the boat headed downwind and spool out all your line. When the kite crosses the line race ends - even though the hull platform could still be yards/meters from the finish line. Little issues like this will make rule changes required - but probably impossible.