Rudder servo travel less than normal

[Levahj]

Been running the Supervee 27 for about a year. Flipped it and got some water in it back in May. Let it dry out and have not used it until last week (first week of August) The steering was not responsive and upon looking found that the rudder travel was all of a sudden much less than it has been in the past. The rudder servo travel adjustment knob on the remote is not the issue. It is turned up to its highest/fullest mode.

Dont know if it is a problem with the reciever (Futaba FP-R122JE) or the servo (Futaba S3003). In researching the parts, it does not seem like Futaba makes the R122JE any longer. Only thing I can find is the R152JE now. Futaba's website is not so good and the specs are impossible to find but it looks like the R122JE has a BEC built into it and the R152JE does not?

Any feedback someone can give on whether it is the Servo or the reciever that is causing the rudder not to move fully would be appreciated. Also, if you think it is the receiver needing replacement would it be ok to replace the R122JE with the R152JE from Futaba?

Thx

[m4a1usr]

Its almost certainly the servo. The easy way to verify is take the Rx out and attach another servo or bring another servo to the Rx. See how it behaves. But the symptoms you are describing are certainly one I have seen before with a wet or damp servo. The FP-R122JE is an old AM Rx and can be found on Ebay if you want a direct replacement.

OSE sells the Traxxas 2075 water proof servo thats a good drop in choice for the Sv27. This might be time as well to upgrade your radio. A cheap 2.4g system can be found on line. Cheaper then a used quality FM system! AM just doesnt have the range and is subject to signal problems from extraneous sources.

John

[JimClark]

Do you just let it dry out? No other maintenance?

[Levahj]

Thanks to both John and Jim for replying.

Yes - all I did was open the hatches and let it dry out for two months. I will try just replacing the servo with a more waterproof one like the Traxxas 2075 and see if that works.

Regarding the receiver, I want to try 2 - 7cell 8.4v batteries with the Supervee but keep hearing you need to add a BEC in order to do so to keep from frying the Rx. On other posts some people say they have no problems with no BEC mods on their rigs and others swear you need to add a BEC in order to not fry the Rx.

The Futaba FP-R122JE Rx which I have has the letters "BEC" right on the case. I am wondering if it has a built in BEC and can handle running 7cell NiMH without any Mod's.

Does anyone have feedback on that?

Thx,

Marc

[JimClark]

I have raced 1/10th scale hydros that are not water tight in fact we easily drain a few ounces out after a heat of racing without flipping. I do not use water proof servos and have had no problems simply because I tear all the running gear out after a race and use a brush and apply corrosion x on all the contacts and open the servo and corrosion x the circuit board and re lube if necessary. I spray the motor in corrosion x and put a light oil on the motor hearings.

[m4a1usr]

The Futaba FP-R122JE Rx which I have has the letters "BEC" right on the case. I am wondering if it has a built in BEC and can handle running 7cell NiMH without any Mod's.

Does anyone have feedback on that?

Thx,

Marc

The BEC marking on the Rx means that it can get its normal operating voltage (4 to 6 volts) from the ESC you are using. Doesnt require a seperate power source. There was a time when a Rx required having a seperate/ dedicated battery and had no such internal capability to tap off of the ESC supplied voltage. Now its normal to do this but you dont see the Rx marked anymore. They just come that way now.

Now having said that, if you have an OPTO isolated ESC it should not have the capability to supply that voltage unless it has a built in switching supply. And you will want to remember that most ESC with a BEC function do not like to operate supplying that Rx power when your batteries are more then 12 volts or 3S.

Here is the kicker, some modern made ESC state they have a internal BEC function for power but give you no warning to not use over 3S. I dont know if thats wise. Most quality built ESC will have that voltage/battery limit warning in their manual. But you wount find it in some the cheaper brand ESC. Take that with a grain of salt. But if you plan on running two 7 cell nimh packs I would not use the BEC function on any ESC. Observe the warning common in other ESC's and your chances of not smoking something are much better. Just remove the red wire from your ESC and tape it off. Then get a seperate UBEC or Rx pack to power it.

John

[Fluid]

But if you plan on running two 7 cell nimh packs I would not use the BEC function on any ESC.

John gave a very succinct response. The only thing I'd change is that with the Castle ICE controllers you can use the BEC up to 8S. They are the ONLY controllers I know that are safe using the internal BEC at high voltage. They work great for me, I can't wait until they offer the marine version.


.

[Levahj]

Thanks to John for his detailed response and Fluids response as well. I find it interesting the stock ESC in the Supervee which with 2 - 6 cell Nimh in series (14.4v total) can run the radio receiver fine but with 2- 7 cell Nimh (16.8v total) can possible fry the Rx. You would think they would have designed it to output a workable voltage to the Rx with both senario's considering the ESC and Motor a can handle 16.8v without frying.

[m4a1usr]

Thanks to John for his detailed response and Fluids response as well. I find it interesting the stock ESC in the Supervee which with 2 - 6 cell Nimh in series (14.4v total) can run the radio receiver fine but with 2- 7 cell Nimh (16.8v total) can possible fry the Rx. You would think they would have designed it to output a workable voltage to the Rx with both senario's considering the ESC and Motor a can handle 16.8v without frying.

In the example you are using its not the Rx that can smoke as much as the ESC. And just the BEC function. Not render it useless overall. Speedos that have a built in BEC function, not all as Jay pointed out, that like a certain voltage range to operate in can overheat above a certain input voltage. Since most of those use switching power supplies, not linear, they begin to get hot or contribute to overall speedo heat when battery voltage goes over a certain point when using the BEC function. There are some that dont. Its always better to err on the conservative side. But if you use 12 volts as your limit when considering a built in BEC useage the odds are in your favor. Read the instructions,... educating yourself to the specific speedo you intend to use and your ahead of the game.


John