microviper 10 esc stutter forward only

[H2Ohaze]

Okay, got the assembly back in the mail yesterday, good packing job. I've got a couple of ideas to try. With spring coming on it may be awhile before I can fully test them out.

Thank you for all the help, I appreciate your trying, and succeeding in diminishing the issues.

[He Who Shall Not Be Named]

Thank you, you are very kind. And Kevin McLeod was a big help too -- he double-checked my work and devoted considerable time to the problem. We swapped out so many things, yet could not, between us, to completely eleminate the ballast sub-system servo chattering. Damn!

And it was bad luck for this job to occure, as it did, sandwiched between the SKIPJACK and Type-23 development and production efforts. Very sorry about the delay -- and my sometimes late updates was very bad form.

Let me know if you eventually figure out what is going on with this glitch -- it will add to the knowledge base.

David

[H2Ohaze]

When I sent the original package out to you, there were two brass Dumas couplings attached to the motor output shafts. These are the only parts I didn't get back. Can you send me two?

[He Who Shall Not Be Named]

When I sent the original package out to you, there were two brass Dumas couplings attached to the motor output shafts. These are the only parts I didn't get back. Can you send me two?

Sorry about that. Of course, and if there are any other items I can slip in there, let me know via email (and your current mailing address) and I'll get it off this week.

dmeriman@aol.com

David

[H2Ohaze]

The fix for blow servo stutter, finally

The props stuttering on forward throttle aren't fixed, and the motors being of unequal torque/friction is still there (I don't think they are critical issues), but the fix for the blow/vent servo (if that system is still used, or a similar one that demands a steady servo on loss of signal) is this:

first, maybe use the Lipo Guard, it seems to work plugged into receiver channel. I have not tested it yet with a low battery tripping the Guard AND my solution in place too. Then plug your servo or LPB pump or whatever into the Lipo Guard. DO NOT use the failsafe on the ADF2. Disconnect it from the line.

After assigning all of your Tx channels to receiver and setting up your microviper esc and ADF2 for leveling only...and any endpoints, etc, then

Plug in the shadow programer into the SL-8 and assign a channel 61-90 if not already done.

Then get Tx on, get Rx on with all things plugged into it. Plug in shadow programer with "96" dialed into it. MAKE SURE all gimbal joy sticks, switches that control one of the eight receiver channels, dials, levers, etc are where you want them to be if Tx communication is lost (like too far underwater). You may want to center the esc stick, but throw the pump switch on, or push the "blow servo" stick fully on... Now press the button on shadow programer until blue light comes on.

Remove programer. Try the servos, esc ,pumps, etc. If they don't respond cycle Rx and Tx. If still frozen, reprogram your channel 61-90.

Everything should respond. Hold some of your sticks, dials etc off from failsafe position- while you turn off Tx. In a couple of seconds you will see all channels hooked up to receiver go to their failsafe positions. Turn Tx back on and they go to where you're holding the Tx sticks.

The info about programing the SL-8 with 96,97,98 for failsafe are in the instructions for it.

David, you still owe me a set of Dumas brass coup[lings...

[He Who Shall Not Be Named]

Addressing the couplers this week -- catching up from a recent 'trip' to the hospital. Good dope on the SL-8 above. Very useful. We're still trying to find a source for 'good' motors.

David

[H2Ohaze]

Hope you are feeling better, David.

If you do find better motors I'd like to get in on that. Maybe drop me a line on getting a new engine room with improved motors/seals installed when you can.

I had a thought on dealing with unequal strength motors, but it's just a bit complex. When designing mechanical things, complex is NOT good. And another esc has to be fit in. But it would make the VIIC turn on a dime, not that I guess it doesn't do bad now. So I'll throw out my left field notion:

Install a second Micro Viper 10 and control each motor separately on channels 2 and three. Right stick is starboard motor. Assign bow and stern plane servos to two dial or lever operated channels 5-8. Throttle channel 3 (port motor) may be able to mix into channel 2, so that throttle will spin both props, but channel 2 will change relative speed (of starboard motor) to each other. Use channel 2 trim for minor changes.

Or a small two motor to one channel mixer may be available.

Can you also send me some extra tubing that plugs into the ports glued onto top of SD Driver...like running to conning tower, back to LPB port at rear bulkhead, etc? I'm going to run gas for right now.

Thanks.

[KevinMc]

first, maybe use the Lipo Guard, it seems to work plugged into receiver channel. I have not tested it yet with a low battery tripping the Guard AND my solution in place too. Then plug your servo or LPB pump or whatever into the Lipo Guard. DO NOT use the failsafe on the ADF2. Disconnect it from the line.

Sir,

Let me be clear that I respect the considerable patience and capability you've demonstrated while troubleshooting this issue, but as the designer/manufacturer (and user) of the LiPo Guard and ADF2 I do not recommend this setup. When you do get to testing it what you will find is that when your LiPo is depleted and the low voltage warning in the LiPo Guard trips you will lose control of your ballast servo in what ever position it was in (likely neutral) and you will not get any kind of predictable result. Certainly, the LiPo Guard will not force your boat to the surface as it is designed to do when correctly connected with an ADF/ADF2.

While I can't provide an immediate explanation for the issues that you're experiencing, I can say that of all the ADF's and ADF2's that are out there yours is the only one I've been made aware of with this problem. I'm still ready and willing to lend what ever assistance I can to resolve this issue, although I do still suspect that there is something other then your ADF2 that is the root cause of this issue.

[H2Ohaze]

Clarifications, and possible fix for reducing motor forward stutter

I thought at the end of your investigation with my engine room on your bench over the winter,
that David had given up on being able to solve the problem...he mentioned that you had also
looked at it and as I understand, had nothing further to offer.

But Kevin please accept my apologies if I am wrong in that conclusion. You do make great
products, I use them in my Holland Submarine, and I even use your ADF2 in a Neptune...greatly
improving its depth handling.

I tried to sell the VIIC sub kit locally in its half assembled state, to no avail.

A sub expert friend suggested I try using the SL-8 great failsafe capabilities as a last ditch
attempt to get signal loss servo blow. It worked beyond expectation, the servo remains rock
solid wherever it's supposed to be.

I had disconnected the ADF2 failsafe but left in the Lipo Guard...and I didn't test for low Lipo
battery, although I have a (dis)charger and Lipo battery charge level measuring equipment. I could
have easily drained the pack down to 3.0 V per cell, but didn't try this experiment. Instead,
I made an assumption that it would work, and posted on this thread that assumption- when it
was not yet proven by experiment.

My apologies for that. Reading the Lipo Guard instructions, I see that it would not work. It would
have needed some way to program it, telling it where to position the servo on low battery. This is
what the ADF2 failsafe section does further downstream.

I'm not the only person with similar issues however. Sattlite also has issues close to mine if not
identical.

Sattlite and I also had a related issue that others have had: motors stuttering when running forward
throttle.



And now another idea for removing motor stutter...

I'm trying another experiment that looks very promising. I took the Lipo Guard out of line, and
connected blow servo direct to receiver. Then I replaced the 2S Lipo battery (7.4 volts) with
NiMh AA cells 2000 mah, trying both 5 cells (6 volts) and 6 cells (7.2 volts).

When I did so, the motors ran much slower of course, but still possibly with enough torque and
speed- but this is a guess right now. I certainly got more sensitive speed change per stick
movement. I actually liked the feel, whether 5 or 6 cells.

I don't want to run the motors too much, heating them up, but for the few minutes intermittent
runtime, there was only one brief stutter.

I then connected back up my 2S 2000mah Lipo battery, with everything else the same. Within 30 seconds
I got perhaps at least 3 stutters. I didn't record actual number, as I was attending to other batteries.
It did run much faster.

I didn't reprogram the Viper 10 after battery swap to a lower input voltage, but I don't know if it
needs to be since the Tx positions remain the same. Is this correct?

I can see a big problem with this swap to NiMh, weight. My lipo is about 3.7 oz and 5 NiMh cells
without solder tabs and wires are about 5 oz

I use 6 NiMh 2500 mah soldertabbed and connected with 16 gauge wire in my Holland sub.
I keep track of time and bring it in after about 30 minutes. Yes, the blow on low battery is nice,
and I would do it if I could, but at least the VIIC will be operational I hope.
In the VIIC application, there has to be enough juice to power the Rx through esc, and operate
the blow servo. A fairly drained NiMh pack is still capable of this, if it has enough cells I think.

I ordered some 2500 mah Eneloops with solder tabs from Batteries America to try.
Latest update is I continue to run the throttle now and then as I install rudder linkage,
and 5 NiMh cells produce no motor stutter that I can detect.

My apologies for length. Please, David, let me know any thoughts you have on foam compensation
for added weight if battery weight jumps to 5-7 oz assembled pack.

In my quest for extra parts(!) I'm adding two magnetic couplers if that is okay with you,
for rudder/planes, as I discovered a long crack
in two of mine. So mag control rod couplers, extra tubing to run along top of SD Driver/conning tower,
and two Dumas brass couplers for driveshaft/dogbones which were missing on your return of engine room.

Again, thank you David, Kevin, all you guys.

[KevinMc]

I thought at the end of your investigation with my engine room on your bench over the winter,
that David had given up on being able to solve the problem...he mentioned that you had also
looked at it and as I understand, had nothing further to offer.

But Kevin please accept my apologies if I am wrong in that conclusion.

It's not that I have nothing further to offer, it's just that based on what I saw there was a larger problem that remains unresolved (the motor studder). When I visited with David to have a look at your engine room we quickly became focused on understanding the motor studder issue to the exclusion of sorting out the ADF/ballast servo studder issue because from what I saw the latter was a victim of the former. Know that there is work being done in the background to further look at the motor studder, but until that's sorted out anything I do is just band-aid'ing a symptom caused by a piece of hardware I don't control. I am however always willing to take a crack at it.

Also, please understand that my biggest concern with your other post was the proclamation of "Hey guys, I have a problem with xxx product and you can fix it by doing this!", but that in "fixing" things that way you suggest it was going to "break" other things as well. That's where I felt the need voice my concern.

A sub expert friend suggested I try using the SL-8 great failsafe capabilities as a last ditch
attempt to get signal loss servo blow. It worked beyond expectation, the servo remains rock
solid wherever it's supposed to be.

So, please calbrate my understanding of the problem as you see it - are you concerned by spurrious motion in the servo when the failsafe is activated, when it's not activated, or both? Also, if the motion is small enough that it doesn't change the state of the vent or blow valves, do you still consider it to be a problem (instead of just a nuissance)?

[H2Ohaze]

I like to have a loss of signal failsafe on all my subs. Using the ADF2 and Lipo Guard with Lipo battery was not causing just always a minor twitching of blow servo now and then when motor is run- servo was sometimes throwing full travel vent-blow-vent-blow...

So of course this may empty the gas and possibly sink the sub, at very least buoyancy will be out of control. This is why I view the servo to be more of an issue than motor stutter. Of course if motor stutter is causing wild swings of the servo, it would seem that is the root cause to investigate.

If I just want to get the thing in the water anyway I can with a rock solid servo that is neutral, vent, and blow and failsafe when it is supposed to be, then using the SL-8 failsafe is a way to do it. I admit this is a patch job. I live with motor stutter. But the servo is good.

But to the more important point of motor stutter: I suggest David and anyone else concerned compare running the esc/motors on a 7.4 volt Lipo vs a NiMh 6 cell 7.2 volt. Just make up the two batteries with same connector or such. You can even run them at the same speeds (lipo will not have the Tx stick up as high).

See what happens. Does the motor forward stutter go away or diminish greatly with NiMh? I'm seeing that, but I haven't run it enough to draw a solid conclusion yet.

I'm not suggesting that you stop using Lipo's in your subs or ADF2 and Lipo Guard for that matter. I'm noticing that the stutter goes away the few times I have plugged in the NiMh pack. So if the Lipo can be tamed somehow with a circuit perhaps so it feeds power more like a NiMh pack....This is just a stray thought, something to get people thinking. And this experiment needs to be done by others.

Regards.

[He Who Shall Not Be Named]

I like to have a loss of signal failsafe on all my subs. Using the ADF2 and Lipo Guard with Lipo battery was not causing just always a minor twitching of blow servo now and then when motor is run- servo was sometimes throwing full travel vent-blow-vent-blow...

So of course this may empty the gas and possibly sink the sub, at very least buoyancy will be out of control. This is why I view the servo to be more of an issue than motor stutter. Of course if motor stutter is causing wild swings of the servo, it would seem that is the root cause to investigate.

If I just want to get the thing in the water anyway I can with a rock solid servo that is neutral, vent, and blow and failsafe when it is supposed to be, then using the SL-8 failsafe is a way to do it. I admit this is a patch job. I live with motor stutter. But the servo is good.

But to the more important point of motor stutter: I suggest David and anyone else concerned compare running the esc/motors on a 7.4 volt Lipo vs a NiMh 6 cell 7.2 volt. Just make up the two batteries with same connector or such. You can even run them at the same speeds (lipo will not have the Tx stick up as high).

See what happens. Does the motor forward stutter go away or diminish greatly with NiMh? I'm seeing that, but I haven't run it enough to draw a solid conclusion yet.

I'm not suggesting that you stop using Lipo's in your subs or ADF2 and Lipo Guard for that matter. I'm noticing that the stutter goes away the few times I have plugged in the NiMh pack. So if the Lipo can be tamed somehow with a circuit perhaps so it feeds power more like a NiMh pack....This is just a stray thought, something to get people thinking. And this experiment needs to be done by others.

Regards.

Now ... that's something I've never considered. I'll give it a try tomorrow. Good stuff. Thanks.

M

[H2Ohaze]

So David, I may not need the extra two magnetic couplers for rods. I seem to have two extra. Yesterday I finished getting the bow planes running, tweaked the stern planes a bit, and the rudder was already working. You can send them to me if you want to. One more of the rudder metal servo horn (the part marked "X" in the pic of VIIC kit on your site) would be neat to have but not necessary. I experimented with position of hole from center of horn on the rudder, and I may need to put a new hole in maybe 3/4 mm further out to make everything smooth, which means a fresh, undrilled horn. I probably also have enough plastic tubing for the plumbing, but I haven't finished installing the fittings on top of SD Driver yet. That's the last thing to do except for balancing (which might have to wait to see what battery winds up in there).

I'm using those 1/16 steel rods with ends threaded about 2 inches long with a screw on clevis (airplane control rods, clevis is Sullivan part # 529). This allows fine tuning of length of control rods-->adjust angle of neutral for rudder and forward bow planes.

For the bow plane rod, I'm either going to pass it under the velcro that pins down the SD driver to hull, or use 1 foot of steel tubing that is 1/8 inch OD but can slide over 1/16 rod to stiffen the long length running up to bow.

Glad to be of help. If I can get other people, esp you guys, to verify, than maybe "battery behavior" can be a solution.

[He Who Shall Not Be Named]

So David, I may not need the extra two magnetic couplers for rods. I seem to have two extra. Yesterday I finished getting the bow planes running, tweaked the stern planes a bit, and the rudder was already working. You can send them to me if you want to. One more of the rudder metal servo horn (the part marked "X" in the pic of VIIC kit on your site) would be neat to have but not necessary. I experimented with position of hole from center of horn on the rudder, and I may need to put a new hole in maybe 3/4 mm further out to make everything smooth, which means a fresh, undrilled horn. I probably also have enough plastic tubing for the plumbing, but I haven't finished installing the fittings on top of SD Driver yet. That's the last thing to do except for balancing (which might have to wait to see what battery winds up in there).

I'm using those 1/16 steel rods with ends threaded about 2 inches long with a screw on clevis (airplane control rods, clevis is Sullivan part # 529). This allows fine tuning of length of control rods-->adjust angle of neutral for rudder and forward bow planes.

For the bow plane rod, I'm either going to pass it under the velcro that pins down the SD driver to hull, or use 1 foot of steel tubing that is 1/8 inch OD but can slide over 1/16 rod to stiffen the long length running up to bow.

Glad to be of help. If I can get other people, esp you guys, to verify, than maybe "battery behavior" can be a solution.

I'll get those additional parts off as well. Tonight I play with different type batteries on these problem-child motors. Good idea, I never thought of trying that. Mike is working with the Chinese (a different vendor) to secure reliable motors. You can only imagine the headache this motor issue has been to our customers, and us.

David

[H2Ohaze]

For grins, you might try both 5 and 6 cell NiMh. I seem to be able to turn the motors with 5 for the 1 oz less weight. But 6 cells would more closely approximate the Lipo 2S voltage-->comparing apples to apples.