surfdabbler

I'm looking at getting a new radio. Ideally, I'd like one which can be used for a sailboat now (well, it's underway), and sailplanes in the future.

A stick controller seems to be the way to go, but all the radios I've seen have got auto-centering sticks for 3 of the channels, and the 4th channel is a ratchet for throttle. For a sailboat, the ideal setup would be one auto-centering stick, and a serials of dials, sliders or ratchet controls for at least 2 other channels, preferably 3 or 4.

So, my question is, what do people normally do? Presumably most boats need at least 2 sheeting controls, for main and jib. Or do most boats link the two? Or, do you use pushbutton controls for sheet in and out, and rely on looking at the boat to see the sheet position?

Alternatively, it would be really cool if radios offered some sort of bypass for the position controllers, so you have an expansion port to plug in external controls, and then you can wire up some sliders or pots or whatever you need for the 4 analogue channels. That would be REALLY cool if this was possible.

On a related note, why do RC sailboats use a jib boom instead of ropes like a real boat? Does this offer better control, or it is easier to connect to the RC system?

jp473

On a real sailboat the jib sheet (line) to you land lubbers, falls aft (behind) the mail mast. It goes through a block (pulley) attached to the rail (side) of the boat. Allowing that nothing is impossible, it would be very difficult to manage a jib on a RC boat in the same way you do a full size craft. Pardon me but I sail 22 to 38 foot boats. But in the RC world we have to get use to the jib having a boom. On the radio you only need a 2 channel. One for the rudder and that generally is a self centering control and one for the sails. That one usually is the stick that will stay in the position you set it in. The 2.4 radios work in a different way than the old school ones. No special frequency range for land or air use. A DX6i (6 channels) is what I would recommend. I use one with my 2 sailboats, helicopter and bower boat. It’s nice to not to have to haul out 3 separate transmitters. The DX61 will accommodate up to 10 of your future modeling needs and is programmable in ways never before thought of. You just need to add a receiver to whatever your next project will be and use the one transmitter. A note on the sail boat. If you get any bigger than 36 inches of 1 meter in scale you will want a “sail winch� instead of a regular servo. The sail requires a bit of torque to hall it in. What size boat are you building? I am working on a North Wind 36 myself.

LtDoc

In no particular order.

Most sail boats require two controls, one for the sails (throttle), one for steering/rudder. Typically the main and jib are controlled together, one control stick.
The center-return on most if not all radios can be defeated, remove the spring, or put one on if you would rather.
So, one way of looking at it is that at least a two control channel radio is the minimum. If you want to get a few 'extra' control channels it's certainly okay, never know when you might need one or two of them.
If you're going to use the same radio system for both air and surface models I think the 2.4 Ghz systems are what you want to look at. That depends on where you live, though. The two types, air and surface radios, are usually not on the same bands/frequencies in most countries. Using one type in another type's area of use isn't exactly the best idea in the world! (And aside from the legality of it, them 'fly-guys' tend to get mad if you cause a plane wreck. Same for the boat people.)
As far as the 'expansion port' idea, don't hold your breath. I seriously doubt if that's gonna happen in the near future, too much $$$. Nice idea though.
Why a jib 'boom' instead of just lines? Cuz it's simpler/easier to do. Ease of use just doesn't always 'scale down' very easy. Certainly not impossible, just not very easy, sort of.
I'm not going to get into the "which radio system is 'best'" thingy, thats different for everyone and with the circumstances, a 'Ford and Chevy' kind'a thingy.
Have fun! Which is the whole idea.
- 'Doc

surfdabbler

Thanks for the replies. Well, I'm not looking for simplicity, I'm looking for authenticity. I will be trying to rig my headsail with sheets. I'm expecting to use quite a few channels if all my plans come together...

1) Rudder
2) Mainsail sheet. Will be winched as per the real boat, with the sheet running through a pulley system, then along the boom, down to the deck and back to the winch.
3) Headsail sheet. Again, hoping to run it like a real headsail, to the deck winches. I want to allow for a few headsails, so will probably use the back-most deck winches, leaving plenty of space for a big headsail, and maybe have some deck pulleys to run the lines through if I'm using a small headsail. (Yes, this might get complicated)
4) Canting Keel (50% chance)
5) 2 dagger boards (10% chance)
6) Spinnaker haul/stow (2% chance)
7) Moveable mainsail sheeting point (0.0001% chance, although the track will be there)

Some of these can be handled with switched channels, others require winches. I can see that the tricky part with winches will be when the sheets have no tension, they are going to move around, and snag, and cause problems. I'm still working on that one.

Yes, I have big plans at this stage, and it's mostly hot-air so far. Also, being my first RC boat, I am aware that I really don't understand what I'm getting into and how hard it might end up being. Anyway, my starting point is to allow for the possibilities, and tackle each one as I reach it.

If you're interested, my boat is a Volvo 70, 1:17.5 scale ([link=http://www.rcuniverse.com/forum/m_8076736/anchors_8077127/mpage_1/key_/anchor/tm.htm#8077127]here[/link]). Waterline length is 33 1/4 in, (36in including bowsprit). I'm not sure how that compares to the official classes, but I'm not building it to race. I'm just building it to build it, and occasionally sail it with my kids. But it's mostly about the building and looking at it.

LtDoc

In that case, I think I would be looking for a radio with at least 4 to 6 channels, if not more. Typically, that means four channels with proportional type control channels and may be two channels of the 'on/off' variety. Four and six channel radios are common, and additional 'channels' can typically be added later, in most cases (mostly a matter of finding room in the radio's case for that addition/modification). Which brand or band of use is a personal choice. I would tend to 'lean' in the 2.4 Ghz band systems, but they certainly are not the only choice you have.
I will say that I think you are looking at a very 'ambitious' setup! Which basically says that I'm not sure I could even remember which thing does what, much less be coordinated enough to handle all them controls at the same time. I do pretty good to remember what to do with just two controls .
- 'Doc

thorsail

Hey Surfdabbler
Maybe some of these contacts would help your quest - Do you know about www.rcgroups.com/forums ? Very good and
active forum like this one , click "sailboats" then go to page two , right at the bottom - there is a thread about a boat called the
Vortex 60 , an older obscure RC sailboat that had a overlapping headsail - there are a couple of pics on that post plus the guy you
might want to Email is Larry Ludwig , who has a video on YouTube showing his V-60 sailing - anyway Larry is www.ludwigrcyachts.com
and he might be a good guy to talk to about jib sheets on big headsails as to what winch he used , etc.
And while your at YouTube , there are at least 2 vids from a guy working on a tilting keel for rc boats , might be worth a look...
I was thinking about your dagger boards - is the idea to have a servo , double horns, mounted on it's side , facing fore or aft , and
each end of a sevo horn is attached to the port and strbd. daggerboard - so when activated as the , say , port dagger goes up the
strbd. dagger is going down , and visa-versa when you tack ? You would want the dagger board to come up through the deck , so
I am pictureing a trunk below decks (p&s) and a slot from which a pin protrudes and that connects to the servo arm(s) ? don't
know about water getting into the boat though - your hull will probably always have heel , and trunk slots would be below waterline?
for fun , check out this site - www.stockmaritime.com German site , they have some very interesting modern design rc
sailboats, twin rudders , I think their top of the line model has a movable keel , big head mains, cool graphics....

Allan
Chicago

surfdabbler

I'm also a member on rcgroups, but had actually forgotten about them. Thanks for the reminder - there's some good stuff there.

For the dagger boards, if I build these in, they will probably be in tubes through from the hull to the deck, so they will be fully sealed, and the waterline won't be an issue. They would then be raised/lowered by an arm that comes up through the deck and attaches to the top of the board.I'm not sure yet if they will be linked to the canting keel or not. This would probably make sense, but in light wind, or running downwind, you'd probably want to raise both boards, so it would be good to have an option for this. I am thinking that for the canting keel, I may make this automatic if I can, just linking the servo directly to a gyro. That would be cool. As you say, the tricky part will be waterproofing the servo area. The canting keel will have a whole set of problems of it's own in this area too.