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Make-a-Wake
03-18-2012, 12:35 AM
Looking for that standard size servo that'll give you some major grunt???

I ran across this bad boy.............threw one in my cart too.............

Nearly 300 oz. of torque on 6v!!!!!!!!!!:rockon2:

Not a bad price either..................oh, waterproof too!!

To put this in perspective, the Traxxas 2056 that alot of us run has 80 oz. of Torque. The "beefed up" 2075 has 125 oz.

SPECS:
Curve gear with smooth Double ball bearing (Si-oil)
3 pole strong torque motor with low signal affect and success get CE certification
Rubber fitting case for waterproof
Heavy duty servo case
Middle heat sink
Design by digital signal with 100% fitting square PWS
Automatic measures central ms
ALU 6061 material of metal gear with light C95 material for light and strong
Digital IC (SOP package with 12bits transfer data)
MOS-FET driver (spirited driver able to push over 7A power)
Weight: 54g / 1.84oz
Dimensions: 40.5 x 20 x 37mm / 1.60" x 0.78" x 1.52"
Torque At 4.8V: 18.8kg/cm , 258 oz/in
Torque At 6.0V: 21.2kg/cm , 292 oz/in
Speed At 4.8V: 0.15 sec / 60° at no load
Speed At 6.0V: 0.12 sec / 60° at no load

http://www.hobbyking.com/hobbyking/store/__9040__BMS_862DMAX_HS_Champion_Digital_Servo_MG_1 8_8kg_15sec_54g.html

Alexgar
03-18-2012, 12:55 AM
yeah but check that price tag

Make-a-Wake
03-18-2012, 01:00 AM
57 bucks?????????? A Traxxas 2075 is $39................

TheShaughnessy
03-18-2012, 02:01 AM
i run a 5 dollar servo with 90 oz, haven't had a problem yet. or i run the 123f from Hobbypartz with 120. http://www.hobbyking.com/hobbyking/store/%5F%5F3743%5F%5FHXT%5F6%5F9kg%5F39%5F2g%5F16sec%5F Twin%5Fbearing%5Fservo.html for the 4 dollar one, though they appear to be out of stock, or these work just fine. http://www.hobbypartz.com/50gexidised1.html, 118 oz, close enough. Seems like a little overkill unless you are running 1/4 scale or bigger.

millzee
03-18-2012, 03:51 AM
this one seems ok too, no good testing yet but is ok for that price
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20537

jcald2000
03-18-2012, 07:21 AM
A couple of cautions about Servos, can't tell you how many I have tryed in the 20 years I have been racing F/E boats, the speed and weight determin how much Operating TQ. you need. speed of the servo means all most nothing for F/E boats .20 sec is just fine in 90 mph boats. I use 80% of the rated Tq. (which is stalled motor, not good1) as a guide.
In the case of servos, a lot more is better, I will not use anything under 200oz rated in a 75 mph boat and anything under 150 oz. rated in any racing boat.
The reason is in an over stressed cheap servo, the servo motor usually locks up and can lead to the loss of the whole boat.
For me saving a few bucks on a servo in a $1,000 boat is not worth it, the choice is yours, just be ready to lose everything.

properchopper
03-18-2012, 11:42 AM
Good topic; since the D19 race is rained out & I'm stuck inside:sad: , a few thoughts :

Totally agree with with jcald2000; speed is not always your friend in boats; a too-quick rudder twitch can easily set the boat downside-up. I've tried servo slowdown modules on my tunnel to minimize this (didn't pan out). Yes, some better Tx's can do this.

Torque is good, but many of my boats are in the sub-100 oz/in range with no ill effects. OPC's do need all the torque you can get (150-200 + oz/in is correct minimum range I've found)

Claims of "waterproof" seem to serve the car guys - splashes on the car track are different from submerged servos on boats. IIRC the "waterproof" Traxxas servos aren't submergance proof - Hitec recently came out with one; haven't heard if it's been tested by any boat guys yet. Self-waterproofing a servo is easy and a good idea.

Flips/trips impart high stress from rudders on internals. Metal gears are a basic requirement. Caution : the popular Hitec HS645MG has a paper-thin metal gear which strips just by looking at it, and has plastic gears in the idler circuit. Rebuild kit is @ $19.00. Forget it-much better buys out there.

My vote for a decent, budget priced all-around robust servo is the HK http://www.hobbyking.com/hobbyking/store/__12451__Turnigy_MG959_Alloy_Digital_Metal_Gear_Se rvo_15kg_75g_0_2sec.html. $23.53. I bought four, one was DOA but I won't wrestle with HK service so I ate it. Needs waterproofing, & kind'a heavy for, let's say a rigger. Interestingly, I opened one up & it had a TowerPro label inside. Even so, good for the price.

Some of the new models mentioned here def bear checking out.

FWIW I use the included plastic servo arms instead of the slick Al ones; rather snap/strip/replace a plastic arm than servo internals.

I recently won this at WWVIII : http://www.spektrumrc.com/Products/Default.aspx?ProdId=SPMSS6030 . If I had to spend the bucks to buy a premium servo this is what I'd buy and assume Spectrum/Horizon should stand behind it.

BTW not too long ago there was a post on a goodie that allowed shortening & recrimping connectors for the plug wires - can't find it - anyone ?

Rained Out,

Tony

Make-a-Wake
03-18-2012, 12:39 PM
Hi proper...................the servo you linked is the one i had "found" a short time back................I have three now, two are powering my 1/6 scale Emaxx and one i just put in my completed 39" MHZ Racemaster.......................Gonna run her today:rockon2:

The reason i wanted this huge torque servo was to go in my 47" Mono in my signature that weighs 20lbs................i think the single 2075 may be the cause of odd steering at times and occasional spinouts.

properchopper
03-18-2012, 12:58 PM
Agreed ! A 20 lb. boat going into a turn at high speed should impose some big demands on the rudder servo !

Make-a-Wake
03-18-2012, 01:12 PM
Plus, there are the brushless..........coreless.............super turbo, servo's out there now for $150 bucks with less torque..................I'll pay my 57 and go on............ordered it by the way.

properchopper
03-18-2012, 01:23 PM
Plus, there are the brushless..........coreless.............super turbo, servo's out there now for $150 bucks with less torque..................I'll pay my 57 and go on............ordered it by the way.

Don't forget to make your servo mount STRONG & SECURE ! [Don't Ask ! ] :doh:

Make-a-Wake
03-18-2012, 01:26 PM
Here's the mount with a hugely thick steering rod...............

properchopper
03-18-2012, 01:41 PM
Here's the mount with a hugely thick steering rod...............

Good stuff. I believe that we both agree that when you build 'em rock solid to begin with, you spend less-to-no time patching things up - I've certainly learned this the hard way (and wince when I see some lightweight corner-cutting construction - plus having to loan out tools and stuff at the lake to repair these shoddy builds - not that I mind doing this but it's so much better to spend extra build-time to prevent this:olleyes:)

Fluid
03-18-2012, 04:05 PM
Let's see - $500 boat, $5 servo. If the servo fails the boat can either: lose the race; crash; run out of control; be stranded in the middle of the pond. Guys will spend $200+ on a motor yet "go cheap" on the servo?

Several club members had boats with control problems - not holding turns, hooking in turns, etc. They were using 70-100 oz-in servos. They switched to high torque servos and guess what? No more problems. They wasted months struggling with their boats but would have avoided all the frustration if they'd spent $15 more on a better servo to begin with.

Note that digital servos have an advantage over "standard" servos even with the same torque and speed. The former have a much stronger centering action, meaning the boat is less likely to wander and wobble in the straights. One mono which exhibited "chine walk" was cured by using a digital servo.....


/

srislash
03-18-2012, 04:16 PM
Let's see - $500 boat, $5 servo. If the servo fails the boat can either: lose the race; crash; run out of control; be stranded in the middle of the pond. Guys will spend $200+ on a motor yet "go cheap" on the servo?

Several club members had boats with control problems - not holding turns, hooking in turns, etc. They were using 70-100 oz-in servos. They switched to high torque servos and guess what? No more problems. They wasted months struggling with their boats but would have avoided all the frustration if they'd spent $15 more on a better servo to begin with.

Note that digital servos have an advantage over "standard" servos even with the same torque and speed. The former have a much stronger centering action, meaning the boat is less likely to wander and wobble in the straights. One mono which exhibited "chine walk" was cured by using a digital servo.....


/Now that's good info.I'm with you guys and don't cheap out,but hadn't thought about the digital aspect.Though all mine are.

TheShaughnessy
03-18-2012, 09:55 PM
Tony,I think I've spent more time on this rebuild of the Vegas then the last two combined. I would have to agree better to do it right the first time. Fluid, I have a 50 dollar motor, didn't think spending 10 bucks on a 120 oz/in metal gear servo was cutting corners. I used the hxt 5010 in a jet boat build, my super vee, and a rudder servo in a .25 plane with no issues. Maybe I'm lucky. If you have a 20lb 60+ mph boat don't use a 5 dollar servo, Duh. For 2-4 s builds the servos I linked are an economical option I've had acceptable results with.

Make-a-Wake
03-18-2012, 09:59 PM
For 30" boats or less the Traxxas 2056 should be fine, 31-39" the 2075................above 40"..............200oz. + torque!!!