Please tell me about servos

Hello again,

Just another quick newbie question regarding servos as I start working on my virgin hull this weekend. (I want to start ordering parts to avoid delays)

What sort of torque (servo) should I be shooting for in order to fire a standard BB-gun (poppit valve), a pair of the same guns for a dual mount, and for a rudder servo (single rudder, county class cruiser)?

I see Maritime Hobbies stocks the Hitec HS-311 Servo (40-50 oz torque) and was wondering if it would work for the guns but if I might need something stronger for the rudder?

Thanks all!
Mack

 

Those servos should work for you. I've found the only time you need anything more powerful than a standard servo is for boats with large rudders or ships with two decent sized rudders. However with a single rudder cruiser a standard servo with 40-50 oz of torque will work just fine. They work just fine for pushing poppets too. No reason to get the fancy high torque stuff yet, and its nicer to replace a $10 servo than a $30 servo if the waterproofing fails and it dies.

 

LOL, I totally agree! I'm retired now and definitely have more time than money. Replacing a $10 servo is most definitely better! Even if it costs $13.99 (Cdn) up here.

Thanks for the very quick response.

 

Don't worry much about servos. "Standard" servo work for just about everything, & if you're paying more than US$10 apiece for them, you're paying too much.

For certain specific cases:

Use a micro or sub-micro servo if you have to put it in a small space.

Use a metal geared servo for elevation/depression since there can be a lot of stress on them & nylon gears often won't hold up to it.

Other than that, there shouldn't be any need for anything other than the ilk that came with your radio. Racing boats' rudders can put a lot of force on a rudder due to the high speeds, & can benefit from a higher-torque servo. You won't see anything like that in a combat ship.

JM

 

If you try rcwings and wheels they do have bulk futaba standard servos. They do not have any hardware but it is worth considering.

 

Thanks again to all who responded. I'll pick up some of the Hitec HS-311's to get me started as I want to support the local store and keep him stocking parts for us. I also think I'll order some of those Futabas that Paul pointed out, they look good (and cheap too).

 

The thing with the Futaba servos is they are not as easily waterproofed as the HI-TEC one are. I found the HI-TECs were able to get a better seal.
J

 

Standard Futaba servos are 33.3 in.oz. and they rum popets.

 

And, of course, Traxxas makes a "waterproof" model in both standard an micr sizes that have been pretty successful contenders and make a good base for waterproofing.

Cheers,

 

do you still have to waterproof those? Im thinking of buying one for my rudder system.

 

They are pretty water resistant, and, for short periods at not overly great depths, might even be pretty waterproof. But I would do some additional steps, like adding some grease to the spline and an external O-ring if I were particularly worried, amdong other standard servo waterproofing techniques.

Cheers,

Wreno