microviper 10 esc stutter forward only

[H2Ohaze]

I can't seem to repeat the results on the battery switchout, either 5 or 6 NiMH. Puzzled. One thing I haven't done is to cut the power leads to the Lipo Guard, although the signal connectors for it are out of circuit. It would be difficult to reconnect either the red or black lead, as they are short. So the Lipo Guard is still connected across the terminals of whatever battery I put in there.

It still might be worthwhile David to see if you get some change switching out batteries...and you could leave out or put in the Lipo Guard as you choose.

I'd be most interested in how a 5 or 6 cell NiMH without Lipo Guard across it, and without ADF2 failsafe works. Removing all the variables kind of.

Regardless, the SL-8 used as a blow servo failsafe on signal loss works well enough to get the sub in the water, although it is a band-aid solution.

[H2Ohaze]

I'm having success with a Tekin B1R esc, made for small rock crawlers. I have cured the motor stutter forwards/backwards. It works with either my 2S 2000mah Lipo or a 7.2V 6 cell pack of NiMH. I can place the esc either a few inches away or right below the SL-8 receiver and next to the LPB air pump with no bothersome issues.

http://www.teamtekin.com/b1.html

I have pushed the throttle on for a limited time of about 5 minutes off and on so far. I can't run it continuously as I don't want motors to heat up. The esc is rated for a brushed 380 motor, and on the VIIC it is running two of what I think are 280 series. I'm hoping this is okay.

The bad news: I still can't get the Lipo Guard/ADF2 failsafe to behave. It now commands the blow servo to over-travel in vent direction with slow throttle speed. No Tx programing could get the servo to blow instead. At fast speed, the servo returns to neutral and then twitches about center too much. When I take the signal path of Lipo Guard/ADF2 failsafe out of circuit, and plug blow servo into SL-8...then program SL-8 instead to blow servo on loss of signal all is okay. The Tekin has an optional programmable cutoff voltage level, but I think one would want the servo to blow, not have the esc shut everything down. I'll use NiMH unless the Lipo Guard/ADF2 which I dearly hope can be made to work, is.

I also get very minor blinking of green LED on the PC board on back of LPB pump when throttle is pushed significantly forward, but it doesn't seem to affect function as it is almost nothing. Much better than the Viper 10 my impression. The dissimilar port/starboard motor torque/speed on startup/slow is still there, going to heroic lengths one could command the two motors with dual escs, these B1R's are very small. Programming some drag brake in I thought helped a little(?).

Other bads: Reverse only runs about 20% of the power that motors have in forward; this can be programed I think, but it has to be done with a USB/PC widget for another $30. When setting up the esc, some Tx brands (listed in instructions) must have their throttle direction reversed (like my Futaba 9C) to work. Not a big deal, just watch out for that. The esc is not waterproofed! I used about 3-4 coats of liquid tape on the small pc board inside the case. But I had to stay away from two programming buttons and six tiny LEDs.

[H2Ohaze]

The Tekin B1R has been tested further with the motors and it hasn't stuttered once.

There are problems when the ADF2 runs the failsafe blow servo still. If failsafe is programmed into the SL-8 with Shadow Programmer command "96" the servo is steady.

If both + and - terminals of the two motors are made separate, two Tekin B1R's can be made to drive the motors independently, again smooth operation, no stutter. Using a programming mix on Tx will allow both to be driven by throttle stick with a rotary knob controlling differential speed of the two props. Simpler though, a mixer circuit might be tried and found better.

[HvyCGN9]

I am having a similar problem....

Finished assembling the SD, still need to make the linkage for the sailplanes. Got the zero bubble set on the ADf2 but still need to set the failsafe, But was able to do a test of the SD in the test tank last night. First by itself then in the hull....good news no leaks, the BAD NEWS massive stutter in the ESC (Viper20) when any throttle is applied (Fwd or Rev) this causes the Adf2 and ballast servo to have a cow. Gave up for the night and watched TORA TORA TORA... (ANZAC day was on 25th lots of WWII movies on). Just changed ESC's for a Viper 15 out of my Salvage tug...But NO joy same problem!

I am running a 7.2v 6800mAh Nimh pack....

Any Ideas....

Cheers Bruce

pre testing

In the test tank....bath tub is just big enough...!!

after test inspection

[Subculture]

Try shortening the wires from the battery to the ESC. If you have to extend wires, it's best practice to extend the motors from the ESC to the motor. If you have no choice but to extend the battery cables then you should ideally add extra low ESR capacitors in parallel with the cables.

Try the set-up with a battery that has standard length power leads, no extension. If you still get the stuttering this sounds like the BEC is overloading.

[HvyCGN9]

hmmm I will try that tomora...

earlier I tried my 540 'truck' motor that used to be in my ply cabin cruiser. Hooked it up to the viper20 and ran it up to speed.....no stutter at all (fwd n rev) and no movement of ballast servo either! Could it be that the 555 in the SD has no Caps built in?? hooked the 555 back up and tried again .....still stutters. Dodgy motor maybe? Will get some caps and solder em on externally see if that helps....

Cheers Bruce

PS how does the motor bulkhead come apart?? may change the motor if its easy enough??

[He Who Shall Not Be Named]

hmmm I will try that tomora...

earlier I tried my 540 'truck' motor that used to be in my ply cabin cruiser. Hooked it up to the viper20 and ran it up to speed.....no stutter at all (fwd n rev) and no movement of ballast servo either! Could it be that the 555 in the SD has no Caps built in?? hooked the 555 back up and tried again .....still stutters. Dodgy motor maybe? Will get some caps and solder em on externally see if that helps....

Cheers Bruce

PS how does the motor bulkhead come apart?? may change the motor if its easy enough??

The provided 555 motor is rated for 12-volts and has two spark-suppression capacitors within the motor case.

Are you using the dedicated BEC as we recommend? And, if so, have you taken the red pin out of the ESC's lead connector?

Is it the motor that is chattering or just the stern plane servo?

M

[HvyCGN9]

yup separate bec and red lead out (I run a separate bec on all my larger models). Stern plane servo and ballast servo go bonkers as soon as the motor starts stuttering..

Bruce

[He Who Shall Not Be Named]

I'm out.

Want me to send you another 555? No problem.

M

[Subculture]

I've been reminded that you require a third suppression cap across the motor terminals, else the other two don't do a thing.

[HvyCGN9]

I'm out.

Want me to send you another 555? No problem.

M

Thanks Dave,

I don't think that will be required mate, How does the motor bulkhead come apart???

I will try Subcultures idea of a third cap across the motor terminals...C if that fixes it.

If that doesn't work I will put my 540 in it. (Its a nice Hi torque jobbie triple suppressed with internal fan) just need to get brass gear off 555 then....

Cheers Bruce

[He Who Shall Not Be Named]

Simple.

Remove the antenna retaining nut and washers; unscrew the two retaining 4-40 screws (that hold the motor-plat to the motor-bulkhead); remove the pushrods; pull the motor-plate clear; unscrew the two motor retaining screws; clear the motor away; replace motor ... recharge flux-capacitor.

M

[HvyCGN9]

Tried a Cap across the terminals for no improvement, then added one between each terminal and motor can (incase the internal caps weren't connected correctly).....seemed to work briefly then servos started playing crazy jitter games again. Took motor out to shed and using a lighter heated up the brass drive gear and carefully removed it, the pressed it on to my 540 truck motor (27 turn 5 pole I think...) installed it back in SD and tested it no servo jitters no crazy ballast blowing!! Now to finish re fitting push rods and back to ballasting!

Cheers Bruce

[He Who Shall Not Be Named]

Well done, sir!

Would you pop the back-plate off that bum 555 motor and inspect the brushes and commutator and report back here, please.

M

[HvyCGN9]

Done.... brushes look fresh(unmarked.....possibly motor not run in !!)and there are two caps in there, likewise with commutator. I will reassemble it and run it in a bucket of water for a bit see if it comes good.

Motor is a three pole type too....

Bruce

.....waiting for test tank to fill....