RC servos gone bezerk

[jinman]

I have several RC boats and only one or two of them that I can operate at the same time without bleed-over between signals. They aren't really expensive, but I had hoped to be able to race them around a circuit. That plan hasn't worked out.

Recently, I took my young grandkids out to play with the boats. One of them is a very fast v-hull. I carefully held it over the water and dropped it in to keep from stepping in the mud. My granddaughter seemed to have problems steering the boat and got it into moss on the edge of the pond. My grandson went to retrieve the boat. Since he had seen me drop the boat into the water, he just pitched it. It hit the water on its side and water leaked inside. All of a sudden, the motor went full tilt and the boat took off across the pond with no response to any control. The boat ended up about 20 feet up on the bank before it stopped. The prop was toast! Since I didn't have a spare prop, our day of boating was stopped even after getting the circuit board dry.

 

[N80]

You should be able to race a dozen boats at once without crossover problems. Lower end radios and AM crystals are probably the source of your problem, but when racing trucks there are 8-12 trucks, bumper to bumper on a small dirt track with no problems.

I don't know if electric will ever do away with nitro. Lots of folks like the noise, the dirt, the oil, etc. I just got tired of all that, but especially the tuning issues. Maybe my motor was finnicky but I could never keep a good tune on it. Or maybe I was just no good at it.

In any case, brushless motors and li-po batteries are definitely going to be big regardless of what happens in the nitro world.

Robert, did you ever get your servos straight?

 

[jinman]

You should be able to race a dozen boats at once without crossover problems. Lower end radios and AM crystals are probably the source of your problem, but when racing trucks there are 8-12 trucks, bumper to bumper on a small dirt track with no problems.

The boats I bought in addition to my v-hull are Zig-Zag racers. They work great, but even with all six channels (yep, I bought 6 of them), they do crosstalk. When I turned on the remote for the v-hull, they would all go nuts. When they work, they are tons of fun. They are fast and will do high speed donuts in about a 6' diameter circle. I've never seen anything turn like they do.

Zig-Zag Racers

 

[denmansoft]

Servos going full range back and forth is a bad reciever (or connectors from Rx to servo). Most good Rx's today will not behave this way on loss of signal from Tx.
RC stuff all has multiple channels to allow races etc. with no cross talk.
Cell phones/bluetooth etc all work on separate bands, BUT.....
Harmonics both up and down can swamp other signals. The bursts of TX from cell phones at 1.8Ghz gives enough broadband noise that my computer speaker inputs act as a Ringer for my cell phone down in the low Khz.

BTW Electrics are the only way to go. My E-MAXX ( with 4 battery packs ) is fast enough that I added a trailer. I can now deliver not just a 6 Pack, but a full dozen beer by RC.
We won't talk about what the Talon will do...

 

[RobertN]

I have been so busy with work and fire station stuff, I have not been able to look at it yet. I should have time this evening.

We've had some nice breezes the last week, so I want to try and take them out this Saturday.

Robert, did you ever get your servos straight?

 

[RobertN]

I re-tested the boat this evening. I reconnected all the original components. This radio/servo combo is labeled as "Aquacraft", who makes a series of RC boats, sail, electric, and gas. It is, however, basically a relabeled Futaba Attack two stick radio, with S3003 servos.

Experiment -1 - I reconnected the original components. Powered up the radio, then the receiver/servos. Again, the servos started moving back and forth to limits. Moved about 20' away; nothing changed. Cell phone is in other room. Turned off radio, and the servos quit moving.

Experiment - 2 - Removed Aquacraft/Futaba radio/reciever. I am building another boat; I have a Hitech Ranger radio set for the new boat. I connected that radio/reciever to the servos in the boat. They still moved around. Shut the radio off, the servos stopped moving.

Experiment - 3 I disconnected the boat servos from the Hitech radio/receiver. I hooked up the sail winch for my new boat, a Hitech HS765 heavy duty servo. I also connected the rudder servo for the new boat, a Hitech HS311 plain jane kind of servo. They worked normally.

Experiment - 4 - I reconnected the the Aquacraft/Futaba radio/receiver, but connected the Hitech sail and rudder servo. Only one channel appeared to work now.

Funky receiver and servos? The receiver was in bag, sealed from moisture. The servos were not, but I have never had more than a couple tablespoons water leak in. I leave the hatch off when not in use to evaporate any water I may have missed; I wipe up any water in the boat with paper towels.

Puzzling....

Note these are basic radios, but are used a lot with sailboats.

Robert, did you ever get your servos straight?

 

[N80]

Have you played with the trim dials yet? Many times I have hooked up new servos and had to change the trim setting on the radio significantly to get them to stop switching.

 

[RobertN]

Yes. I neglected to note that in my "expieriments"

It did not seem to have an affect. Both of the boats rudders are installed pretty accurately; they did not need trim. The sails I usually have set in the center of trim adjustment too.

Have you played with the trim dials yet? Many times I have hooked up new servos and had to change the trim setting on the radio significantly to get them to stop switching.