Steering issues

[merin_83]

Hi Guys,
I have the new wraith poison sypider, and installed the castle BEC 10A and 3S lipo 2200mah (20C), the issue i face is that when on rock or hard surface, some times the tires wont turn even if i give steering inputs. But as soon as i move feet or so, the wheel turns, what could be the issue ? I have HR aluminium tie rod set and TowerPro MG946R servo and aluminium servo horn. Speed seems pretty good. Please help.

thanks,
merin

[k7zpj]

The TowerPro MG946R has 180oz of torque which is pretty light weight for a Wraith. A servo for a Wraith needs to have around 350 to 400 oz of torque.

[envious8420]

what is the voltage on the bec set at? iirc it is 5.1v from the factory. You want 6v to get the most out of that servo.

[merin_83]

Originally Posted by envious8420

what is the voltage on the bec set at? iirc it is 5.1v from the factory. You want 6v to get the most out of that servo.

yes its at factory settings 5.1V i dont have a castle card. But even if i boost it to 6V, how much will be the difference ?

[merin_83]

Originally Posted by k7zpj

The TowerPro MG946R has 180oz of torque which is pretty light weight for a Wraith. A servo for a Wraith needs to have around 350 to 400 oz of torque.

here is what am confused, i thought MG946R is a 12Kg servo(as advertised in ebay) which is equal to 420oz approx ? am I doing incorrect conversion ?

[envious8420]

12kg. = 166 oz. in.
Yes the increase in voltage will make an improvement that will be noticeable. do you have a hobby shop local that may lend you a cc link or card or atleast set your bec at the correct voltage for you?

google calcrc and download the program. it has all kinds of different calculators. top speed ,torque, gear ratios ... tons of good stuff.

also check out valuehobby.com a power hd 1501mg servo, 236 oz. in. at 6v for $12.50 Ive read some pretty good reviews on this servo and will know thursday for sure. (i ordered one to test out.) not for my wraith but for a losi scte.

http://www.valuehobby.com/radio-syst...hd-1501mg.html

hope this helps.

[altd896]

Your only converting as if it were a mass not torque.
Torque is a measure of force x a lever length, thats why it its ozf-in (1oz x 1" lever) or in this case 12kg/cm which is it's stall load, it actual operating load is more like 10kg/cm

[k7zpj]

Originally Posted by merin_83

here is what am confused, i thought MG946R is a 12Kg servo(as advertised in ebay) which is equal to 420oz approx ? am I doing incorrect conversion ?

Here is a link to the servo's specs calculated in oz.
TowerPro MG946R Servo Specifications and Reviews

[merin_83]

oh okay, got that, thank you guys..... any suggestions for low/avg budget 400oz servos ?

[johnnyh66]

I have one of these in my mini crawler and I just bought another as back up to the Hitec's in my scalers.
I don't know if it'll last as long as a Hitec but for less than $20... I'll find out!

Solar Servo D772 High Voltage 0.17sec@7.4v 64g Digital Metal Gear

[merin_83]

Originally Posted by johnnyh66

I have one of these in my mini crawler and I just bought another as back up to the Hitec's in my scalers.
I don't know if it'll last as long as a Hitec but for less than $20... I'll find out!

Solar Servo D772 High Voltage 0.17sec@7.4v 64g Digital Metal Gear

thank you, i had checked couple of these, but even if i could change my bec voltage to 6, then speed is only 2sec is that correct ?(currently i have 17 sec speed)...

[envious8420]

.17-.20 seconds. speed and torque are 2 different worlds. more speed doesn't = more torque more torque doesn't = more speed. that solar is rated at 7.4v too so at 6v output will be less. unless you want to wire it up with you battery leads so it gets the correct voltage. a lot of receivers wont like 7.4 volts running through them and really wont like the amperage that goes with a high voltage servo.
I have a hitec 7954sh wired direct to my battery leads and just the signal wire going to the rec. its a beast like that but it was like $99+. keep your eyes open in the for sale sections of your fav rc forums and refer back to the servo database like that k7zpj posted (just type the servo name and model # into the search) to check out the specs. or just Servo Database - RC Servo Specs and Reviews I haven't found a servo yet that i couldn't find in their database.

[merin_83]

Originally Posted by envious8420

.17-.20 seconds. speed and torque are 2 different worlds. more speed doesn't = more torque more torque doesn't = more speed. that solar is rated at 7.4v too so at 6v output will be less. unless you want to wire it up with you battery leads so it gets the correct voltage. a lot of receivers wont like 7.4 volts running through them and really wont like the amperage that goes with a high voltage servo.
I have a hitec 7954sh wired direct to my battery leads and just the signal wire going to the rec. its a beast like that but it was like $99+. keep your eyes open in the for sale sections of your fav rc forums and refer back to the servo database like that k7zpj posted (just type the servo name and model # into the search) to check out the specs. or just Servo Database - RC Servo Specs and Reviews I haven't found a servo yet that i couldn't find in their database.

thanks for the information, sorry actually i dint frame my last question correctly. I know if we less the voltage less torque is obtained (from specs). but at the same time, i see the speed is reduced to 2sec, which i saw in other threads as less than avg servo speed?

[envious8420]

you get what you pay for. In life and at the hobby shop. lol!