Servo Sizes for .21 rigger

[TCHedOff]

I just got my engine today (a used .21 Novarossi) and now I want to start getting all the misc to set up my first .21 rigger. The carb moves really easily, so I'm wondering how low in oz/in can I get away with? As for the rudder, it seems I've read that I shouldnt consider any under 100 oz/in (but I cant remember if that was for this size boat or not). Thanks,

todd hollander

 

[Chris Wood]

todd.

go to www.servocity.com

they have what you need.

depending on what reciever you use i use futaba on the rudder. i think the number is a 3301?? i don't know for sure as i am not at home.. but it is somewhere around 120 inch oz @ 6.0 volt I would shoot for that size.. it is a standard size servo.

as far as throttle and 3rd channel.

use a hs 85mg.. i think they are around 40 some oz and it is plenty.

they are mini's.

hope i helped

chris

 

[RaceMechaniX]

40~60oz for the throttle and mixture and 100oz for the rudder. Also greatly depends on the throw used. If you can properly match the servo horn throw to the rudder throw you probbaly find you don't need a lot of servo to move the rudder. i.e. if the linkage is 1" away from the center of the horn you end up with the rated torque of the servo (they measure in oz per inch), but if you mount the linkage at 1/2" you increase the torque. I think most servo's have 30 degrees of travel to either side with EPA set to 100%, you probably only need 15 degrees to either side for a rigger.

my 2 cents.

TG

 

[TCHedOff]

40~60oz for the throttle and mixture and 100oz for the rudder. Also greatly depends on the throw used. If you can properly match the servo horn throw to the rudder throw you probbaly find you don't need a lot of servo to move the rudder. i.e. if the linkage is 1" away from the center of the horn you end up with the rated torque of the servo (they measure in oz per inch), but if you mount the linkage at 1/2" you increase the torque. I think most servo's have 30 degrees of travel to either side with EPA set to 100%, you probably only need 15 degrees to either side for a rigger.
my 2 cents.

TG

Thanks for such quick replies! You both have helped alot and confirmed my thoughts (much to my relief). I will check out servocity (never heard of them) in a minute (have already been to Tower and checking options/pricing).

todd hollander

 

[TomMoorehouse]

100oz for the rudder?

A lot of guys are using the hitec hs225mg and it seems to work great! I've been using mine without problems for years.

http://servocity.com/html/hs-225mg_mighty_mini.html

 

[RaceMechaniX]

I just err on the side of a little more than needed. Heavily depends on the weight of a 21 rigger and rudder blade.

 

[TCHedOff]

I just err on the side of a little more than needed. Heavily depends on the weight of a 21 rigger and rudder blade.

Tom: That Hitec is 67 oz/in, and no problems.... less weight and WAY cheaper.

The weight of the rigger is 3lbs - just hull.... that change anyone's thoughts?

 

[Chris Wood]

100oz for the rudder?
A lot of guys are using the hitec hs225mg and it seems to work great! I've been using mine without problems for years.

http://servocity.com/html/hs-225mg_mighty_mini.html

I can tell you with certainy. I used to use a servo about the same torque.. i switched to a over 100oz torque and man did things change for the better.. boats started to track the way they should.

chris

 

[steve wood]

hitec 225 tend to go up in smoke

 

[Don Ferrette]

hitec 225 tend to go up in smoke

I'll second that, had 3 in a row either smoke or were DOA out of the box. I went with Futaba 9405 for steering & 3102 for throttle & 3rd channel in my Blackbird 21. B)

 

[TCHedOff]

Don: I've been wanting to ask for 3+ yrs - how'd you get that lime on that cats head!!!!!!!!!!!!!!!!

I cant express how FUNNY that pic is!!!!!!!!!! (Our cat would rip your arm off if you tried).

BTW It's hard to argue w/ Natl racers and world racers.... I'm all ears.... and I've read til my eyes are bleeding. G-night

 

[tmunn]

would the Hitech 85BB work for needle and throttle.Is the MG really needed ??

 

[moparbarn]

would the Hitech 85BB work for needle and throttle.Is the MG really needed ??

i won't swear it's ABSOLUTELY needed, but the extra smoothness/accuracy,reliability & longevity make it worth it, imho. while they're not riggers, my .21 tunnels all benefitted from higher torque mg servos...............

 

[John Knight]

would the Hitech 85BB work for needle and throttle.Is the MG really needed ??

REALLY needed? NO, but would STRONGLY and ABSOLUTELY recommend it. The cost difference is how much? Tiny. They take a LOT of vibration in these boats, especially riggers, so get the better one.

 

[tmunn]

O-K that is what i thought but the shop i was going to use does not have any just the BB's I will order them with metal gears.

Terry

 

[TomMoorehouse]

I still recommend HS225. i've only lost one and it got wet. I replaced it with a Hobbico CS-35MG It is even smaller and has given me no problems yet.

 

[Don Ferrette]

Don: I've been wanting to ask for 3+ yrs - how'd you get that lime on that cats head!!!!!!!!!!!!!!!!
I cant express how FUNNY that pic is!!!!!!!!!! (Our cat would rip your arm off if you tried).

BTW It's hard to argue w/ Natl racers and world racers.... I'm all ears.... and I've read til my eyes are bleeding. G-night

As I have mentioned before that's not my cat. That pic got sent to me about 5 years ago and it still makes me laugh. None of my 3 cats would put up with that either if I tried.

 

[Preston_Hall]

I have run a 9202 for years now. They were kind of pricey and about 70 inoz of torque if I remember correctly.

I recently purchased a JR standard size servo that has over 100 inoz and was under $40. It has been doing fine in the car it is in. I wouldn't get a fast servo as they don't drive as well. It actually isn't the servo but the driver.