I am in the process of building a 6 ch. rc skiff, around 48 inches overall, but have servo questions… for the sheeting lines, halyards, and righting moment channels, i need 2 sailwinch servos EACH, on y harnesses. thats TEN sailwinch servos on one recievr. Even with a bec reciever, and a rc car battery or two, i dont think a standard reciever can handle this kind of current. any suggestions?
i would like to make winch setups with motors drawing from a separate circut, but dont know how to incorporate external potentiometers.
Need to know more specific details and I’ll help you get it right. On my spinnaker and movable ballast boats I use Guyatt winches hooked up direct to a 7.2 volt battery. The Guyatts have a built in regulator so in some cases you can hook the Guyatt up to a 7.2v battery and plug it in to the receiver to supply 6v to the receiver. Depending on the other servos you use you can also use a regulator separate from the Guyatt to supply the receiver in which case you have to cut the red wire on the Guyatt’s receiver connection.
Please let us know some more details of your boat and if you let me know the exact servo’s/winches you’re using I’ll help you with the set up.
I’ve done quite a bit of experimentng with a “Trapeze Power Ballast System” to provide RM on a Melges 24 model, a scow model ,a 50" skiff type hull and a F48(D4Z) model . This system required two winches for side to side movement and fore and aft movement plus a main/jib winch and rudder winch. The Melges also had two additional winches for an asymetrical spinnaker for a total of five Guyatts! Plus a rudder servo(9000 series)!
Again, I’ll help in any way possible but lets hear somethng about your boat-sounds very interesting!
Doug Lord
–High Technology Sailing/Racing
i was thinking cheap hitec winches in pairs for controls, but on the righting moment channels i would like a faster responding winch, especially if i want to use rc heli micro piezo gyros with adjustable gain, to really torque the boat down with a fast response. this boat will pretty much follow the lines of a 49er, with several size weight bulbs for the keel, the better you get at keeping it upright, the less weigt you need on the keel. around 6’ mast, maybe smaller heavy wind rig, mast top chute, carbon hull.
ch 1 rudder
ch 2 main / jib trim
ch 3 spin trim
ch 4 spin halyard, jib furl, pole launch, vang release (all simultaneous)… only non proportional channel(switch)
ch 5 weight fore / aft
ch 6 weight port / starboard
if i use guyatt winches would i need a separate battery for each servo? or just on a few?
Or could i just plug in a esc with bec into the unused ch. 7 slot, not wire up a motor to the esc, and use a rc car batt plugged into the esc? regardless my biggest concern is to not fry a rx with too much current.
btw thanks ive put so much thought into this design i really need some outside opinions. =D
On my Melges 24 model I ran 5 Guyatt winches(4-380’s) off one 7.2 v battery using a separate regulator to supply power to the receiver…
Another thing for your consideration: the best radio I have found for spinnake/power ballast system combinations is the Futaba 9c(formerly 8UAP) because of the three dials located across the face of the transmitter. On my set up I used:
Ch 1 for rudder
Ch 2 for fore and aft movable ballast
Ch 3 for mainsheet/jibsheet
Ch 4 for side to side power ballast system
Ch 6 for jib slot
Ch 7 for spinnaker set/douse
Ch 8 for spinnaker trim.
Those dials make it easy to access the spinnaker controls and jib slot control.
Putting the movable ballast on the sticks works very well since the “sense” of the controls are the same way they work on the boat.
As a suggestion : on the Melges I found that by using a little longer than scale retractable bow pole that I did not need to furl the jib at all. Similarly, on the boats I build with symetrical spinnakers the jib remains up…
On my asysmetrical spinnaker I used a single winch for set/douse and a single winch for trim. Each winch had a custom made drum: 1)the set/douse winch had a drum with three winding paths-the third winding path was used to induce and remove slack 2) on the asy trim winch I had four winding paths-two small ones were used to induce and remove slack from the spinnaker sheet as the boat gybed.
If you use Guyatts for these winches Rob will make the drums you need.
If you’d like to discuss exactly how you’re using your winches I may be able to help you think it out a little diferently. None of my boats used winches on y connectors-you may need to I don’t know but it may be worth discussing.
Are you canting the keel for movable ballast or slinging weight over the side or both?
Doug Lord
–High Technology Sailing/Racing
there will be a fixed keel fin, with a track mechanism for righting moment. I am on a limited budget so i would really like to go with hitec 725bb sailwinch servos , wich use 6.0v rx batt, as they are only 48 bucks.
on some of the control lines the winches will be running reverse purchase systems to extend total line movement.
it would be nice to use small rc airplane motors geared down as winch motors, micro servos hitting switches changing polarity, and small switches on control surfaces to disable throw at maximum deflection (crude potentiometer), but here water proofing is an issue. this craft should be so unstable without micropiezo gyros that it should be watertight! thanks alot for the help, my ideal setup would be to y harness dual winches per channel, and use a rc car battery hooked up to a esc w/ bec without a motor installed… i guess the bottleneck here is recievr overload, and if this is the case, does anyone know of a high current reciever for this application?
appreciate the info
just called and asked tower hobbies if their 7 ch rx would handle the setup mentioned above and they said it could handle it.
Kiteboard
An ESC with BEC with no motor connected won’t work. If you read the specs most can only handle 2-4 servos. In plane applications they won’t work for a 4 servo wing glider that has 6 servos in the plane. Your planning on more winches then that. The voltage regulators in BEC ESC’s aren’t the greatest and can only handle a relatively small range of reciever load before the won’t supply the reciever what it needs to operate correctly.
You can buy a BEC unit that is better then the BEC’s built into speed controls. You can buy one at Hobbylobby (www.hobby-lobby.com) NewcreationsRC has them also for around $30. The seperate BEC’s can handle something 10 servos with a motor battery of up to 20 cells. The standalone BEC would work for you as you power the winches off what is normally the motor feed and power the reciever off the reciever output.
Tower is no expert in anything. You should contact the manufacturer’s support and explain what you are doing.
For the best radio advice I know of contact Tony Stillman at Radio South in Pensacola ,Fl. 1-800-962-7802
Be carefull on rc heli gyro’s: a “normal” rate gyro probably won’t work well at all. But a “Heading Hold” gyro holds promise : I talked to Rob Guyatt about the biggest problem fairly recently. And that is matching the winch speed to the gyro speed-if they don’t match it won’t work. It just so happens that Rob was about to experiment with an extremely fast motor for a new version of the 280-which is already fast enough for sail control. I said that when I could I’d send him a heading hold gyro so he could see if he could match it to the 280. You can contact him and mention this and he may be willing to give it a shot. It is absolutely critical the winch and gyro be matched…
On your movable ballast you might consider this: when a performance boat like a skiff is sailed flat any ballast on the end of a fin is just sitting there adding weight but negligible righting moment. But it is necessary to have ballast underwater or else you could not recover from a knockdown.
So what I’m doing on the “unlimited” version of my next movable ballast boat is to have both a canting keel and an on-deck “Trapeze Power Ballast System”. You would have the minimum ballast in the keel necessary to at least partially right the boat after a knockdown and put the rest on deck.By having both systems(powered by a single winch) you have the safety issue covered and all the ballast is “active” not just sitting there…
One thing you should be aware of is that boats with hull shapes like the Melges ,I14, 49’er do NOT want to plane like the fullsize version. It’s something to do with the physics but the phenomenon has been noticed by a number of people. On the other hand a skinny hull along the lines of a Moth, JS 9000 and many model designs has ben shown to fairly easily exceed theoretical hull speeds…
Before you outfit the hull completely you might want to make a series of towing tests with it(at sailing weight) to watch it’s behaviour. If you do this have the rudder radio controlled and pull the boat with a line attached at the center of effort of the rig… If you have any questions post them here or e-mail me directly...lorsail@webtv.net
Doug Lord
–High Technology Sailing/Racing
kitebored,
I am a bit confused as to why you need 10 sail winch servos…
Since you are putting the servos on Y harnesses, you want them to respond in a simultaneous manner to the commands. So unless you need the extra torque of a second servo, it seems like you would be able to load both sheets on one drum (with two grooves in the drum.
As such, you can use one servo that would handle both spin sheets (easing out the port sheet while trimming in the starboard sheet and vice versa), one servo to handle the halyard and douse line (eases the douse line while trimming the halyard), one servo for the main and jib trim and one servo for the side to side ballast. I would think you could handle the fore-aft ballast with a smaller servo than a sail winch by having the servo angle the ballast rack relative to the boat centerline. This could probably be done with a standard servo, but you might need a high torque servo. The rudder can be a standard servo. So as I count it, you need 4 sail winch servos, one high torque servo and one standard servo…
- Will
Will Gorgen
kitebored,
I dont know if this is what you are looking for in your comment about :
" i would like to make winch setups with motors drawing from a separate circut, but dont know how to incorporate external potentiometers."
but I have a diagram of a small circuit consisting of about 8 components that will allow you to control the position of a winch/servo off of a potentiometer and a battery. It is not incredibly efficient in my oppinion but you could set your boat up with a nice sail winch to control the sails and hook that up to the reciever that controls your rudder servo and then several micro servos. Each of those micro servos then hook up to a potentiometer in this other circuit that runs each of the winches off of a seperate battery. Once again, not the way I would do things, but it will definately accomplish what you would like to do (run some of the winches off of seperate batteries). If this would be of any help, please drop me an e-mail at brownt@alum.rpi.edu. The circuit has been published to test servos and make sure that they are operating properly without a TX or RX.
PLEASE USE THE FOLLOWING POST WITH EXTREME CAUTION!
I just talked to one of the electrical engineers here at “work” about this. Here is what he had to say.
==============================
set up your reciever with a battery pack powering it.
Take your winch, and run a battery pack DIRECTLY to it (posative and negative/gound connections).
Connect the two ground from each batteries such that they now share a common/global ground.
run JUST the signal line (normally white) from the reciever to the winch.
====================================
I admit . . . im slightly scared of trying thisone, but might be worth while for you to try out. Anyone have any old sacraficial gear to try this on? AM RX and a couple winches??
Tonight I might look at this with a multimeter and figure out if it should work. . . then maybe hook something up.
~tb
~tb,
The two winches in my Schooner, both have built in voltage regulators, the RX and the rudder servo are both supplied from the winches.
The main Nicad is in the forward hold, there is NO seperate Nicad for the RX.
The winches were made by David Andrews, who was taken over by Whirlwind Winches when David retired.
Test with a test meter only, if there is anything wrong, it won’t cost any money!!faulty electronics that smoke, will NOT fix!!.
There is a way to wire my winches to be powered from the RX, but it has never been used.
John.
Jay-Dee
I have several whirlwind winches as well as a couple futaba s5801’s that behave the way you have stated. the original question though is how one would set up several different Hitec drum winches such that you could power them off of several seperate batteries instead of all draining the pack that is trying to run the reciever. I think the count was 8 or so winches, I dont know how well that would run off of one battery pack. Using multiple battery packs could be good ESPECIALLY if you can carry the two seperate battery packs as moveable ballast instead of lead! If you can turn your ballast into useable current, why not!
Maybe I am miss understanding JayDee, you have 2 winches, do each of them have their own dedicated battery pack?
~tb,
Only one nicad supplies all, both winches, the RX and the rudder servo.
Both winches have voltage regulators, but only one will be working, the other one shuts itself down - -not required!.
The main nicad is 7.2 volts, the winches working voltage, the volt regs drop that down to 4.8 volts for the RX and servo.
Only other nicad in the boat is a 6 volt one that runs the bilge pump only.
System has run for 15 years, annual checks for corroded wires and connectors only.
The nicads usually are the first things to fail,
now have 7Ahr " F " cells fitted, industrial quality, seem to be ok.
In light conditions the Schooner will sail for almost 10 hours non stop, the winches use most amps.
When “nature calls” there is always folk waiting to get to my Tranny!.
Photos at www.john-dowd.co.uk
John.
wow thanks for the interest. yes, in this case i dont think one winch per channel would be enough, each winch is coupled with its pair, so each winch is doing half of the work. This boat will be extremely unstable (fun), due to the large amounts of sail area and i would rather be on the heavy side with double winches than underpowered and burning up winches. Yeah wgorgen there is no point of having one winch for each port and stbd. spin sheet, or righting moment, bc. on each tack one winch is still doing all of the work. I think the bec module available from hobby lobby is exactly what i need to supply enough juice. Now I think im going to stay with hitec winches over home made motor winches because they are more water resistant.
if i get a micro piezo gyro with adjustable gain, is the gain setting how i match its ‘speed’ with a servo or am i totally off? would a non piezo gyro help?.. I think it would be awesome if the boat was in a bathtub without sails and you pushed with your fingertip at the top of the mast… and the weight moved automatically to counter… this boat will be REALLY hard to keep upright so is there anyway to still use a gyro with hitec 725bb’s? btw ive made so much progress on this project since i posted this thread, props to this forum, posting threads really gets ideas and information flowing!!!
Kitebored- an rc heli gyro will generally specify the minimum response servo required but heres the rub: that responce is occurring with a servo that is moving + or - 45degrees; the total range being one quarter of one revolution.
A "Trapeze Power Ballast System"could have a three foot track requiring + or - 3.3 revolutions of a Guyatt winch over the whole range. For a Gyro to work the winch must be capable of moving the 3.3 revolutions in about the same time as the servo moves ONE EIGHTH of a revolution!
It wouldn’t take much time and would be highly beneficial if you sent your gyro to Rob Guyatt–after e-mailing him and receiving a go ahead.
You cannot expect to use a hi tec winch for movable ballast in my opinion.
Doug Lord
–High Technology Sailing/Racing