Whinch Winch ?

[Usagi]

I'm looking for help on winches. The RMG seems to be the recommended winch however it isn't cheap. The cheapest I found was $225.00. I'm looking for alternatives that won't break the bank and I found these:
http://www.hitecrcd.com/servos/show?name=HS-765HB ($39.99 at Tower Hobbies)
This is a sail-arm type with 140 degrees of travel and
Speed: 0.28 / 0.23 sec @ 60 deg. and
Torque: 152.75 / 183.31 oz.in (4.8v/6v)

http://www.hitecrcd.com/servos/show?name=HS-785HB ($49.99 at Tower Hobbies)
This is a winch type with 3 1/2 turns of the drum and
Speed: 1.68 / 1.38 sec @ 60 deg. and
Torque: 152.75 / 183.31 oz.in (4.8v/6v)

http://www.hitecrcd.com/servos/show?name=HS-815BB ($44.99 at Tower Hobbies)
This is a sail-arm type with 140 degrees of travel and
Speed: 0.19 / 0.14 sec @ 60 deg. and
Torque: 274.96 / 343.01 oz.in (4.8v/6v)

I have an 815BB which is installed in my Victor Ruby B. It is quite powerful and I suspect might break bones.

Which of these would be the best choice for an EC-12 or is there some overwhelming reason that I should sell my first-born to get the RMG ?

Thanks

~~Usagi~~

[PaulP]

I had a Hitec 785 in one of my "loaner" boats that I used for visitors at our site. We learned that with any amount of wind, the winch would not sheet in - it was necessary to bear off to sheet in.

Not Recommended

The RMG's are a little pricey but if you are doing any racing at all, you'll want one.

Paul P

[greerdr]

There is NO QUESTION here.The RMG is so superior to any alternatives I've tried or seen as to make the discussion moot.Spend the money and read the book.This product is worth the price and Rob has helped many of us figure out how to work his minature work of art to sail the EC-12 well.
Fair winds,Following seas and hope to see you with us on the pond soon.

R.C.Greer

[Usagi]

Here:
http://www.ec12.org/Clubhouse/Discussio ... PIC_ID=734

It was stated that the Ozmun W-12 proportional swing arm winch has "... 180 oz. in. of stall torque."

And later in that post Rick West said it worked well for the Delta fleet.

The 765 and 785 barely equal the W-12 in stall torque with 5 batteries but the 815BB is well over 180 oz/in (274) with 4 batteries and a whopping 343 with 5 batteries.

~~Usagi~~

[s vernon]

I guess torque numbers are not always reliable. Better to rely on the experience of other people. And that is why you asked the question. And asking and getting good answers will hopefully save you some grief.

RMG (or possibly the 5801) is the only winch for someone who is even remotely serious about racing.

I believe the 785 being a drum winch would be far superior to the 815 and the 765 could not possibly even be considered for an EC12. You do understand the "advantage" that a drum winch has compared with its rated torque? 140 degrees for the arm winch versus 360 degrees times the number of turns for the drum winch. I believe you could sort of say that the torque gets multiplied by the total number of degrees. And still people have had bad experiences with the 785.

Scott

[Rick West]

Much money was spent on things for the EC12 that did not work out well. The building site and this forum were developed to mitigate this waste and share what is learned in the building process.

The winch is the heart of the EC12 sheeting system and has reached the fine point of sail control that competitors on the water must have. It has taken 10 years to get here with good resolution to sheetline movement through programming and the fine armature rotation we have with the RMG winch motor. This and the experimentation in drums related to the rotation turns has been refined to the point there is little more wanted on the water. The latest in full radio board building with a complete sheetline system integrated has now included the newer servos and radio gear. It is great and it is not cheap nor should it be. My guess, having built a new one for this season is that the board and gear installed is around $425 without the RX. The RMG winch is simply the best we can get in performance and reliability. Coupled to the computer processed 2.4ghz radio systems with the latest in programming features and trimming, serious competitors have never had it better. When you are the best you can be on the water it is then mano e mano.

The 5801 is still being used. The Ozmun W12 is also still in some boats and this servo-ized motor performs well but is temperamental in adjustments. It was preferred for simple sheeting systems but like the 5801 is not going into new building today and is being replaced during refitting. The RMG has overwhelmed the winch market and is used even in the smaller boats because of its control features. It is the choice and will not be obsolete for years to come.


...94

[Larry Ludwig]

I have used the Futaba 5801 drum for years in many many boats including many EC-12's and it has worked just fine. It has the power and speed to do the job, and has one extremely nice feature that the RMG does not. You can adjust the length of sheet on the top of the servo with a simple screw driver in the same amount of time it took you to read this. Also, it costs $140 from TowerHobbies.com which has a special right now where if you spend $150 you take $20 off your order.. so if you get another $10 worth on your order you could lower the cost of the winch down to $130.00

I have installed this winch in numerous customer boats over the years and have had outstanding results. It doesn't have all the features that you may program in on the RMG, and only half the torque, but it does have a 31" payout on a 3 second run full travel the RMG is just under 2 seconds. Usually for me, the faster I move something, the faster I moved it incorrectly... so I don't mind the extra 1 second.

The RMG certainly is a technical marvel, and 90%+ of the racing skippers use it, but this is a viable alternative and one that lends itself to "upgrade" in the future if you decide you should need the RMG as they are both drum winches.

[Usagi]

The Hitec 785HB :
Torque: 152.75 / 183.31 oz.in (4.8v/6v)

The Futaba 5801:
Torque: 109 oz-in @ 6V - 136 oz-in @ 7.2V

The RMG 280D /280DL
Stall Torque 221 oz.in(280D) 276 oz.in(280DL)

It's pretty obvious that the RMG is more powerful however it also appears that the Hitec is more powerful than the Futaba. But Larry Ludwig says that the Futaba is perfectly adequate while PaulP says that the 785 was too weak for a EC-12. Those opinions conflict with the torque figures. If the Futaba works as well as Larry says, then the Hitec should work even better, especially if a 6v supply (5 batteries) is used.

I found that Bob Szczepanski, a member of my club, (Triangle Model Yacht Club) uses two Hitec 815BB winches, one for jib and the other for main. He tied for 5th in in our regatta a few weeks ago so it appears that the RMG is not mandatory for racing success.


~~Usagi~~

[Larry Ludwig]

Nope, the RMG is not mandatory, and personally, I like the Robotzone swingarm better than all the drums when you get right down to it... but this was more about drums. Arm winches have in my experience been considerably more reliable than drums.

The dual 815 setup is interesting, and you can even use a radio with servo mixing, and plot the curve of the relationship of the sails to each other... which is great, but I can tell you from racing J's with independent winches... it's GREAT when you get can see your boat, to be able to trim that way... but when you are on the backside of the fleet... you are really up against it...that is where a proportional single winch is needed because you can move the stick on the Tx to a known position, and be reasonably sure that the sails moved to the position that you wanted. Also, a standard setup of main/jib together with a jib trim is essentially the same thing.

The 5801 is the lightest on the torque, and it will not rip the main boom in on a "A" rig in 16 knots of wind, the RMG will. The 5801 meets the 90% curve for performance. It is not the absolute best, but it is an economical alternative that provides acceptable performance through all but the extremes of the envelope.

[bigfoot55]

Larry- What "Robotzone" swing arm would be recommended for a EC12? Website is not active. I have an old 12 (1975) with a non-proportional Probar (not Dumas).
Winch is worn and no comparioson to the RMG in the other boat. but I do not race it. Like to put in a proportional but not spend the money for a RMG.
Tom

[john richmond]

Hi Tom, I'll jump in here and give a comment, I'm new to the EC-12's but have used the Robotzone in Santa Babara class with great success, I used the Robotzone SPG815 with 3:1 gears this gives over 1000 ounce-inch of torque on 6V and 42 sec. for 140°. I think the sail plan is about the same on a EC-12 as a S/B and the boat weight is about the same so it should work just fine.
john EC-12 #316

[tallastro]

Here's a link to the PowerGearboxes in Servocity's Robotzone
http://www.servocity.com/html/servo_pow ... boxes.html

I have an RMG but I like the behavior of my arm winches with other class boats. Some of my bias may be the other classes themselves. I still haven't grown to enjoy the EC12 as much.

[Usagi]

After studying this thread and learning about external gearboxes (thanks tallastro), I realized that the stall torque values alone are not enough. One has to consider the swing arm's length and the winch's drum radius. The standard RMG drum's radius is .5 inch. With a stall torque of 221 oz-in the force at .5" would be about 500 oz.

If one wants the same stall torque from a swing arm first there is a 2:1 mechanical advantage of the typical setup, that is, the sheet moves two inches for every inch of movement on the servo arm. The average Ec-12 swing arm has a 5" radius. so 500 oz @ 5" = 500 x 5 = 2500 oz-in. But there is also a 2:1 mechanical advantage which would double the force needed so now we're looking at about 5000 oz-in to have equivalent power. (check my numbers)

The best that can be done with a power gearbox is 1,715 oz-in which is close to 1/2 the torque of the RMG... but how much of the 5000 oz-in is overkill?

It sure would be cool if someone would care to measure the force needed to bring in the sails in 'gale' conditions, say 20 knots. I doubt that many of us would ever sail an EC-12 in over 20 knots. From what I've seen at my local club, at that point there is often more equipment failures, dismastings etc., than not being able to bring in the sails.

Speed seems comparable. The RMG will do 14" per sec which is probably about full sheeting where the 815 with a 5:1 gearbox takes about 2 sec. for full travel. That's half as fast, but that might even be an advantage. With a lesser gear ratio which will give less torque, the 815 can actually be faster than the RMG.

Price of the 805 + gearbox, rigged for 180 degrees is about $100. They'll assemble it for you for another $30. The 805 appears to be the same as the 815 except that the throw is 90 degrees which can be changed to 180.

As for winch types, Using the standard drums for each winch I calculated their speeds:
Hitec 785HB = .5 =inches per sec
Futaba 5801 = 8.37 inches per sec
RMG = 12.56 inches per sec

The Hitec is so slow as to be unbelievable. However I doubt the difference between the Futaba and RMG would be significant in a race. The RMG has about twice the torque (109 vs 221 oz-in) of the Futaba but is that needed or is it overkill?



~~Usagi~~

[greerdr]

Have you ever had a sheet bind that "stalled" the winch? Did you figure it out fast enough to prevent a fried servo?
A really beautiful function of the "mini-brain" in an RMG is the "quit pulling when something's wrong" ability.
The travel adjustability of an RMG when combined with a 2.4 radio is awesome.
Look carefully at Rob's product in the top sailors boats in most regattas and you may be persuaded that the RMG is worth the extra money.
For me the 280DL ROCKS<b></b>

R.C.Greer

[Rick West]

Sorry guys, this is not a matter of the best winch but one within a cost realm. This is not uncommon in building and we hear about it here. Cost can move recommendations and let it be chosen. Maybe we will hear the result.

I vote for RMG or Ozmun and will let it stand till I here better in building.

...94