which servo?

[Sam EvansParticipant @samevans47801]

I’ve recently purchased a Thunder Tiger Victoria yacht and a 2 channel Futaba control system with two Futaba 3003 servos (one for sails and one for rudder). After several runs in different wind speeds, i’ve decided that the servo is not powerful enough to operate the sails in most wind speeds, as it only has 3.2 Kg.cm of torque, and the pulley system means the torque supplied to the sail ropes is only half of that. Can anyone give me advice as to what servo or torque range I want? It has 433 square inches sail area. I don’t really want to spend any more than £40 on one and the servo has to be standard size.

 

Thankyou

Edited By Sam Evans on 23/01/2011 17:16:38

[Sam EvansParticipant @samevans47801]

[Gareth JonesParticipant @garethjones79649]

My wife built a Victoria about 2 years ago and it was a very successful introduction to model boat building and sailing. We used a Futaba 3003 servo for the rudder and a 3014 high torque servo for the sail winch. The radio system was operated from a 6 volt battery pack to improve the servo output torque to Futaba’s figure of 6.2 Kg.cm, roughly double what you have now.

 

We also made a few minor modifications to the sail control system. We used monofilament fishing line with a smear of vaseline for the line which is directly driven by the servo arm. This reduced the friction compared with the stranded line supplied by Thunder Tiger. We also slightly rerouted this line to minimise any un-neccessary bends where it ran aft out of the hull. She sold the yacht last summer so I cannot show you any photos of the mods we did but it did sail very well, as good as the 6 or 7 other Victorias that are sailed at our pond.

 

[Gareth JonesParticipant @garethjones79649]

Sorry, I made a minor error in the above posting, the Futaba 3014 servo torque at 6 volts should have read 6.5 Kg. cm, not 6.2 – every little bit extra helps.

[TelstarParticipant @telstar]

Hi Sam Hitec do a sail servo HS-765HB, Slightly larger than a standared servo, that works with Futaba system rated at 11 Kg.cm.

Works on my RM.

Cheers Tom

[Sam EvansParticipant @samevans47801]

thanks guys.

 

The Hitec servos seem a lot cheaper than any of the other brands. Is this because they are lower quality or because the other brands (e.g futaba) use incredibly expensive but not particulary necessary materials? i’m keen to know.

 

would anyone else recommend using fishing line for the main control line? (it’s not that I doubt you Gareth Jones its just that fishing line would be quite hard for me to get hold of so I wondered if it’s necessary).

 

thanks

[TelstarParticipant @telstar]

Hi Sam

I use Hitech because they are cheaper, and give the same quality of operation as more expensive brands.

for the sheets( controle lines) I got some nonstretch kite line. All you need is string that dosn’t strech under load/when wet, as this can allow it to come off pullies/guides etc. and has a known good breaking strain

Cheers Tom

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