How to choose a servo

[Elias Vazquez]

Hi,all

I'm wondering if there is a formula that is used to find out which servo to buy eg.boat weight to torque oz. etc.

for i am in the process of building several new boats, A,B,C,& twin engine Outriggers,.thanks for any help.

Elias

 

[Hydro Junkie]

Not really, though there are some common sense answers out there. In general, the bigger the boat, the more torque the rudder servo needs to have. For example, a scale hydro should have over 100inoz of torque while a Sport 40 should have over 75. In the case of your twin rigger, I'd be looking at a quarter scale with over 200inoz. For more info, I'd recommend contacting Mike Hughes, Gooycheese and Tom Moorehouse who are all members of this forum as they all run and/or design riggers in the classes you are talking about

 

[jeff baham]

i use the futaba standard size servo with 70 in-oz torque for my sport 40 and 40 rigger,3302 1/4 scale futaba servo ( 110 in-oz)for my 67 hydro. and futaba 5302 1/4 scale (200 plus in-oz) for my twim 67 rigger,

 

[nitrotwin]

While not being the best choice I run the same rudder servo from a 21 rigger to a 67 mono hitec 645mg 133 oz at 6 volt and I also use the 85mg for everthing else and I keep two spares that will fit anything that I run.

 

[Hydro Junkie]

Thanks guys, you made me look like I know what I'm talking about. I like it B)

 

[gooycheese]

On my .12 boat I have a hs85mg for rudder and hs65mg for throttle. On my .21 boat I have hs225mg on rudder and hs85mg on third channel and throttle. On my .45 boat I have a hs645mg on rudder and hs225mg on third channel and throttle.

All of these are riggers.

Hope this helps,

Paul

 

[Ed.R]

After a bunch of years with cars and a couple with boats.This is the first thing I look fore in a servo or any radio equipment... " Futaba"

Ed

 

[Hydro Junkie]

After a bunch of years with cars and a couple with boats.This is the first thing I look fore in a servo or any radio equipment... " Futaba"

Ed

For my boats, both Sport 40 and scale, I have S3305 servos on the rudder at 99/124 inch/ounces of torque, a 3101 for the sport 40 throttle at 22.2, S148 for all other throttles at 33/42 while I have a S9350 for a T-Boat rudder at 111/139. These are all controlled with R113IP receivers. I guess I'm a Futaba fan too, Ed

 

[Ed.R]

After a bunch of years with cars and a couple with boats.This is the first thing I look fore in a servo or any radio equipment... " Futaba"

Ed

For my boats, both Sport 40 and scale, I have S3305 servos on the rudder at 99/124 inch/ounces of torque, a 3101 for the sport 40 throttle at 22.2, S148 for all other throttles at 33/42 while I have a S9350 for a T-Boat rudder at 111/139. These are all controlled with R113IP receivers. I guess I'm a Futaba fan too, Ed

That became because I had experiances with other brands.My steering servos are 3305 with 3102 for throttle and third channel.Thats with D sport tunnel and .21 tunnels both mod and sport

Ed

 

[Don Ferrette]

Futaba all the way for me! 3002 for throttle, 3102 for 3rd channel mixture, 9405 for steering in scales and everything up to .80 size boats, 5301 for steering the gassers, big singles and twin riggers. All running on a 3PKS with 2.4 FASST module and 603FS receivers with the optional 15" antenna leads. I also use separate Venom failsafes in everything as I prefer the non digital Futaba servos. B)

 

[Bert Dygert]

don,

Where do you get the 15" antenna extension for the Faast radio's. My local hobby shop can't find them. Are they only available through Futaba? Need the extension to get the antenna out of the scale boat.

Thanks for the help!!!

Bert

 

[Don Ferrette]

don,

Where do you get the 15" antenna extension for the Faast radio's. My local hobby shop can't find them. Are they only available through Futaba? Need the extension to get the antenna out of the scale boat.

Thanks for the help!!!

Bert

Contact Futaba Service Center- http://www.futaba-rc.com/contact.html

 

[larcor69]

why would anybody want to use a 1/4 scale servo is beyond me, they make servo's that put out well over 300+oz/in in a standard size why use out dated eqmt. in your hull that you have 1000's of $$$ in??? futaba/JR/ airtronic's make good stuff and its the lastest greatest stuff, 1/4 size is so early 80's thing

 

[Grimracer]

Gear train and (in some cases) output spline durablity.. thats a great reasion to chose a 1/4 scale servo..

Grim

 

[Don Ferrette]

why would anybody want to use a 1/4 scale servo is beyond me, they make servo's that put out well over 300+oz/in in a standard size why use out dated eqmt. in your hull that you have 1000's of $$$ in??? futaba/JR/ airtronic's make good stuff and its the lastest greatest stuff, 1/4 size is so early 80's thing

Nope, wrong answer. The gearsets in 1/4 scale servos are way stronger! Also the actual mechanical leverage is better with the larger gears. I know that sounds weird but it's true and I proved it to a guy a few years back who could not get his mod 7.5 o/b tunnel to turn consistently. After watching him thrash all afternoon at the pond I talked him into taking one of my Futaba 5301's home with him and replacing his rather pricey high output standard size servo. The following weekend that same boat with only the servo change went around the turns like it was on rails, he said it never drove that well ever before. That $80 1/4 scale 5301 servo put the smack down on his $150 "hi torque" standard one. B)

 

[NITROSNIFER]

I am slowly moving over to Futaba for all my servo's to many lost planes and races due to Hitec servos crapping out. I haev a box of hs81, 225, 645, etc that show no sign of water intrusion but they just quit. Nothing sucks more than losing a race due to a throttle servo quitting. I was always a big Hitec fan until a few years ago when no matter what servo I bought they lasted one race, half a season etc. Have not had any issues since with the Futaba in same set up.