Is there a relationship table (or something like that) that relates sail area Vs servo torque?
I need to control a 2250 sq. cm. (349 sq. inches) sail plan… What strenght/size/type of servo should I look for?
Thanks again for the support.
The more I practice, the luckiest I get.
2250 sq.cm is the sail area of a rg-65, is this your boat?
You need a servo with >= 5kg torque at 4,8 V.
That’s right, I’m building a RG-65… But none of the material I’ve found so far deals with servo sizes/strenghts… thanks!
The more I practice, the luckiest I get.
That is about the same sail area as the Wheeler Class here in the US. They use Guyatt RMG 360 winches.
You can check them out (and order them) here: http://www.users.bigpond.com/rmgsw/
Will Gorgen
Will:
I couldn’t find the 360, but the 380… Is that the right model? Also, which ‘cheap’ alternative may I consider? This is my first boat, and I don’t want to go top-notch with it (probably the boat itslef wont deserve them)…
Same question applies for the rudder servo…
The more I practice, the luckiest I get.
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by mholguin
Is there a relationship table (or something like that) that relates sail area Vs servo torque?
I need to control a 2250 sq. cm. (349 sq. inches) sail plan… What strenght/size/type of servo should I look for?
Thanks again for the support.
The more I practice, the luckiest I get.
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
If it?s the same RG-65 I?m thinking about (http://losveleros.cjb.net/), something like a CS-70 should be more than sufficient (http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXANT4&P=7) .
I think the plan calls for a standard servo.
As for the rudder servo you can use a cheap standard servo, the ones that come with the radios.
Hope this helps.
Gio
Thanks Gio. I started with the Palo de Agua, but switched to a more “normal”, rounded hull I designed.
Will look into that later on…
The more I practice, the luckiest I get.
http://www.rcsailing.net/forum1/topic.asp?TOPIC_ID=1197
There you can find some pics of my progress (or lack of thereof)…
The more I practice, the luckiest I get.
Will, the Wheeler carries 2000 sq. inches of sail while the RG-65 only 2250 sq centimeters (some 349 sq. inches). Also the LOA of a RG-65 is 65 centimeters (25.59 inches)… One wheeler can carrie my RG-65 (and myself)!
The more I practice, the luckiest I get.
Hmmmm -
I missed it too. Will !
square <u>CENTIMETERS</u> - not square meters or square inches or even square millimeters !
Maybe time for an agreed upon standard for measurements? [:D]
MKS…international as I recall [;)]
-Wis
_/ if it isn’t broken, don’t fix it! _
i use hitec’s hs645 mg on my kyosho seadolphin.its sail area is close to the rg65 and it still works fine after 5 yrs of use and abuse in salt water sailing
ed
Geez! I am usually really good with english and metric units. 2250 square CENTIMETERS not inches. That is much much smaller than I thought…
The 380 is going to be WAYYYYY too much winch for that small boat. You should be fine with a standard servo or even a small sail winch.
Sorry to mislead you…
Will Gorgen
All:
I think is would be really cool to have a table relating torque Vs sail area. That would be a great help for newcomers like me… Is it to much to ask?
Thanks for the support, guys!
Marino
The more I practice, the luckiest I get.
CONCLUSSION:
1.- Standard servos will do the job
2.- No table exists relating sail area to servo torque (maybe a winter project for someone savvy enough with too much snow?)
Thanks! I will try to post a conclussion or answer for every question I post, let’s see how it goes…
Marino
The more I practice, the luckiest I get.
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by wgorgen
Geez! I am usually really good with english and metric units…
Sorry to mislead you…
It would be a rule of thumb basically because sail area is only part of the equation. The shape of the sail is going to affect how much torque is required to handle it. A very high aspect ratio rig such as you would find on a M class would not have the same requirements as the same 800 sq in on a Soling M for instance.
It’s a small difference, but enough of one that could affect the decision of which winch to install. Also the geometry plays a part since different length booms mean different amount of sheeting required, ergo different winch choice.
Local knowledge is worth 10 strokes, so see what everyone else is using and you will be spot on. As to the RMG 380, I use it on a 4300 sq in J boat and it handles both sails correctly. That’s horsepower![:D]
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by mholguin
CONCLUSSION:
1.- Standard servos will do the job
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Hi Marino,
definitively NO!
A stardard servo ist not strong enough for a RG65. In my JIF.65 i first used such a servo with 3,5kg/6V and it could not hold the sails. Then i changed to a Graupner 5077 with 5,0kg/6V but it has also problems in gusts.
Now i have a servo with 7,5kg/6V which works fine in all conditions.
Back to the drawing board then…[:-ashamed]
Marino
The more I practice, the luckier I get.
