Great video. And, your work on the ROV is a fun winter time break from watching the boat build. Thanks for the upload!

LOL i clicked on part two, and it was from 2010. amazing how far you guys have come in video quality in just 3 years! i will now wait for the new part 2.

this is the best channel on youtube, thank you for uploading your projects!

Thank you for your vids. US Navy uses shaft driven ducted fans with the duct rotating and attached to the vanes the inlet is then left open to the radius of the torpedo. The fan is the same diameter as the torpedo. This is a very efficient design as it reduces blade tip turbulence and windage losses. If you gimbal the motor/fan mount then you get vectored thrust. on another note if you grind a small flat on the shaft and pack the bearing void with grease you prevent water flow through your bearings. Torque on a DC motor is much more important than RPM turning a large slow propeller is much more efficient than a high speed screw/prop try letting the motor run much slower 200-400 rpm as the seawater will shed heat 40 times faster than air you should have a good result Happy New Year.

Happy new year to you and your family! Keep up the good videos.

Glad to see you back at this project. (bout time:0)

Happy new year, I think the use of advanced technology is perfect, the brushless motor with controller is the best you can use for small thrusters.

Hi Doug, I Follow your work since the very beginning, years ago...... I saw all your videos and your work is amazing. I always wait your next video.... Years ago I found you because I was also doing a deep ROV and your firsts tests on bruchless motors was very interesting for me. Just to share my own experience, (I have my own boat and leave near deep sea) , I have built some ROVs. When you want to explore down to 300 ft (100m for me) , it is not a real very big problem, it can be done... but when you want to go deeper, the problem is not the ROV itself (motors, camera, housing etc) but the real problem to face is the theter and the control of the boat the theter and the rov.... You really have to consider that it takes a very long time for the rov to go deep and, during this time, on the surface, your boat is moving due to the wind ( on such deep seas, you cannot anchor), so you move. You also have to consider that your rov is also moving and, due to the size of the theter it is very sensitive to the current drift. If you want to compensate the drift of your boat using boat engine, there is a hight risk to beak the theter... So, this is the only very big problem I was not able to fix......so I use other solutions. Thanks for your very good videos. Georges

@SVSeeker

10 жыл бұрын

Hello Georges Thanks for writing. I've been thinking about that problem too when we deploy something like this from our boat. But the specifics conditions in this case are optimal. The ROV will be towed about 100m behind a side scan sonar fitted with a dive plane. The umbilical from the side scan to the ROV will be a thin reinforced single twisted pair, and currents at depth in the Black Sea are almost zero. So when the side scan finds a target and the surface ship slows to stop, the ROV will be about 60m from the target, either port or starboard. Time to target will be less than 2 minutes, the dive plane will act a bit as a sea anchor,and the bulk of the cable from the side scan to the surface will also have little to no current. For deployments is less favorable conditions I'm considering mimicking that setup, with a heavy downrigger weight leading the ROV by 100m or more. Then it would be a matter of keeping the downrigger within 50m of the target until the ROV can get a visual. I'd be interested to hear more about what you have tried and any ideas you might have for improving the plan. --Doug

I think it's a great idea! Cheap, low tech, expendable, yet functional.

you are amazing with all your projekt!

@SVSeeker

10 жыл бұрын

Thanks, were doing all the things are school teachers told us not to do.

Very interesting videos, thank you.

amazing project!

@nicolabrida6351

10 жыл бұрын

IN questo progetto ho visto servono motori Brushless da modellismo reperibili sempicemente

Just some input from my experience as an RC plane/heli flyer. I've found in the past, after crashing a plane into the ground, that sand and other debris can get in between the magnets and windings and lock up an outrunner pretty good. Maybe you need some sort of fine screen to prevent stuff going into the motor.Also, when selecting ESC's to control the motor, get one that is programmable and has variable motor timings. I've found in the past that if you load a motor up too much the motor can stall and the magnetic field keep rotating, it makes a horrible screeching noise, because after all all this stuff has the assumption of being used in the air, not under water. I know you said you wanted cheap, but have you had a look at the "CNC Precision Jet Boat Drive - X-Large" from Hobbyking? It might give you some ideas.

Still chuckling about your "don't be an ass about it"! Gets old quick don't it! Good Luck on your project!

To do the shaft extension on rc race boats I dremel a small flat spot into some 3mm rod and use electrical block brass couplers with the two screws and a small amount of loctite I did once use that with a bearing and spring in one of the blocks holes and a grub screw to make an adjustable drive shaft that pops into notches along the rod By the way your projects inspire me to use my knowledge in more usefull ways I live in Hampshire england land here is insanely priced so 75' steel boat would cost me £350,000 just for the land but I am looking into building a composite boat and like your adaptive planning because it does work keep up the amazing voyage doug

@SVSeeker

10 жыл бұрын

Holy Cow! Immigrate to Oklahoma. We paid $1400 for our lot, 4.5 miles from my office downtown. Yeah, lots of your neighbors are crack heads, but their quite crack heads. :)

@jm-ux5dk

10 жыл бұрын

What! thats crazy here in hampshire youd pay 250,000 for a little 3bed house squished between your neighbours. It looks like oklahoma might need a visit in the future to be honest I dont mind what people do as long as theyre cool with me. My town has crackheads too but they are looney crackheads tearing up the streets for change stealing peoples dogs and such.

I wonder if Bel-Ray waterproof grease would work for the motors with space between the bearings.

do I even need an ESC if I'm using an arduino? I could just control power/speed by the program code I write.

Couple of thoughts. First, on the potting, whatever you put in there is probably going to have better thermal conductivity than the air that's in there now. Since the coils are stationary in these motors I'm not sure how much air flow there actually is in normal operation so you may actually be improving things by potting them and submerging them. On prop pitch, remember that on your big boat the prop pitch is optimized for a diesel's speed/torque/efficiency curve and the boat's hull speed. The diesel is happier spinning near max RPM and the pitch is flattened to match your slower displacement hull speed at that rpm so you can hit the motor's sweet spot while cruising. Electric motors have a completely different torque curve, they hit peak torque at zero RPM and it declines from there. For your application you might be better off with a steep prop and low RPM. Just some thoughts. I'm enjoying watching you guys build, I might have to swing by OK on my next road trip. ;-)

Love it. More! More!

i've watched this channel since you made your forge foundry furnace. i think your awesome, and you where talking about a flex drive-shaft , could use a drill extension or a 3/8 universal joint ratchet extension

Friendly tip: KV stands for revolutions per volt. If a motor is rated at 1000 Kv and you give it 12V, then 12,000 RPM is the peak rpm it will reach. The significant in an immediate sense is 1. the kv directly relates to the torque constant Kt which is expressed as in/oz/amp ie torque per amp my recall is 1352/kv = kt in in/oz 2. max power is at 50% of peak rpm and max efficincy will depend on the type of motor - for good brushless in runners use 88-90% for car motors use 78% of peak rpm Your esc just runs the motor as hard as you push the throttle. If its brushless you need to set the timing and operating frequency to suit the motor. If its brushed your controller doesnt care it just puts out the power you throttle it to modified per any adjustments you make in the esc. at the Kv is rpm/v - the esc has only aminor effect on the motors speed - the rpm/v figure and the actual volts in your pack determine the motor speed

Thanks for the video. I think you are on the right track with using the out runners as they are meant to go slow enough for pretty large air props and the efficiency should remain pretty high as long as you are near the higher end of the rated voltage. Generally the efficiency gain you get from a higher speed motor is not worth the transmission loss going through a gear box and I would wager keeping the thing simple would give you better results. I'll second the previous comment about the marine varnish... I doubt anything more that that would add any benefit. All that said, I have no experience with putting this stuff under water (let alone at pressures) but at the low cost of these motors running a few tests wouldn't hurt much. :) I'd guess the bearings are going to be the most temperamental part.

@SVSeeker

10 жыл бұрын

That's my worry about gear heads too, because they would have to be oil compensated, and that's of lot of little teeth pushing oil around. Right, except that again removing the notches between the magnets might make the housing more streamlined. We'll just test on befor and after potting and see what we get. Yeah, I think ball bearings are the Achilles heel. That's why I like that brass bearing in the Donkey motor.

A homebrew beer club, had a pump that which was used to pump brewing wort around the system. It was a magnetically coupled motor to impeller. We ran into issues when the impeller got gummed up on the shaft. The issue was solved when the tolerances between the impeller & shaft was increased. I was wondering about the close tolerances of the bearings and if the microbial sea life might have the same effect. I would be surprised if the RPM of those fans in water was in the thousands.

what about using such design in sea saltwater?

so cool is it!!!in anything you show in video have description and type!!!thainxx

I'd recommend considering gearboxes as you get more slow speed power(control) from larger props. These little RC motors like to run fast (even out runners). And if you are going to use a gearbox, you might also consider inrunners. The moving parts are smaller/smoother so you should/might have less power loss from spinning water around, even with the gear box ( also inrunners are slightly more efficient if I remember right) Also, are you making this ROV for someone else to use in the black sea, or for yourself using the black sea ROV plans?

Mind those electrolytic capacitors on the ESC when youre under pressure, even if its just oil. They might do fine, they might crush, they leak oil in, but burst upon the pressure outside dropping, etc... I'd do some pressure cycle testing, and if they are problematic, check out solid polymer caps, or other types of non canned capacitors.

With the thermally conductive potting, its a good idea to do it under a vacuum to make sure there's no air left in any gaps.

@SVSeeker

10 жыл бұрын

Yes, I saw that! Think that's what will do. SOLENOID COIL EPOXY POTTING WITH MAX MCR EPOXY RESIN.wmv

Have you ever thought of trying using a motor from a computer hard drive? They are quite powerful & don't know if they will work on your project, just a guess. Happy 2014 & can't wait to see you back on your boat project. Oh and tell Kay she is doing a great job working with you.

i watched the video and need to know how to get some these motors

I can explain the thermal conductivity if you like. Let me know and Ill make up a quick video.

Where can I find the prop you cut down shown in this video? Thanks! Awesome project!

@SVSeeker

10 жыл бұрын

Sorry but I don't have a supplier for those, I got them off eBay years ago.

Doug: The signal to an RC controlled device is a pulse width modulated signal. "Neutral" is usually a pulse with a duration of 1.5 milliseconds. The pulse width usually ranges from 1.0-2.0 milliseconds. You'll have to determine what those speed controllers do with the pulse widths by experimentation, but I'm guessing that a 1.0 millisecond pulse will run the motor full speed in one direction and a 2.0 millisecond pulse will run the motor full speed in the opposite direction. Generally, the pulse repitition rate is not too critical, but from memory is around 15-30 milliseconds between pulses. Most RC servos will hold their last position if the pulses stop, but I don't know what the speed controllers will do. A simple test circuit to generate pulses can be made with a 555 IC Timer and a few readily available parts. Do a search for "Astable oscillator 555 timer" and you'll find heaps of circuits. The three wires to the controller are; Black=Ground, Red=4.5V (5 volts will do too), and White=pulse input. Also, the pulses are positive logic (high=on) and if a pulse line is let go to a high steady state, some RC servos will run to their stop and keep pushing. So it's best to make sure in your Arduino software that when (if) the pulses stop, you pull the pulse output to ground. HTH Scott

@SVSeeker

10 жыл бұрын

Thanks Scott. That makes sense. Running the motors is something I've done with a "Pololu" controller, and Arduino looks just as easy. We just have to provide a value to the controller card and it sits there and pulses the ESC until we change the value.

as for the bearings you can also use the brass bushings or you can try using ceramic bearings a little expensive but are much better and the the balls ceramic some of them also have ceramic or delrin races. And the speed control even the environment you intend to use them in will give off a lot of heat the heat sinks and or fans are for cooling the small electronic board inside if it gets to hot it either burn up board components or de-solder

Hi Guys, A couple comments based on my experience doing a similar project. I used brushless motors on my ROV and they work great. Here is what I learned: The bigger reason to pot both the stator and rotor is to reduce turbulence, especially on the rotor where there is space between the magnets. This will save you lots of power, that would otherwise be used to thrash water around inside the motor between the rotor and stator. Pot them and then put them in the lathe and polish them to be smooth. Buy a controller, or better yet design and build one, that will let you turn the motor very slowly.If turned slow then the prop pitch on those fan's will not be a big deal. Electric motors make to torque right from the start so there is no need to spin them so fast - unless you are using it in an RC car or plane of course. I'll help you with the controller design if you need it. To cool the controller use the liquid used to cool high performance PCs. You can find it on the gamer sites under overclocking or liquid cooled pages. Then enclose the controllers inside an aluminum box with the hull being on side. Don't pressure compensate that box - the pressure will distort any electrolytic capacitors in the controller. You could try swapping out the electrolytic capacitors for Tantalums and see if the do okay at 3K depth, but I never tried that. This will work with all your electronics by the way. Acrylic view ports can be made cone shaped and fit into a cone machined recess. Use grease, not an o-ring. The fit should be very tight. They will leak on the way down - but at around 2K the pressure will push the acrylic hard enough into the steel support to make it water proof. I tired this after o-rings kept blowing out and it worked great. This is how the ports on subs work as well. Have fun! Leo

@SVSeeker

10 жыл бұрын

Good stuff Leo. The turbulence issue makes sense. We want to stick to COTS, Consumer Off The Shelf parts so this can easily be replicated. Can you recommend an existing motor controller that runs the motor at lower speeds? What about stepper motors or gear head motors? Which path might be the most power efficient? Good cooling idea, We might put them in a oil bath, but weight inside the hull is going to be an issue. We'll know more once we get to the point where we can work on buoyancy. Right all the electronics areas are 1 ATM, Woods Hole did some pressure testing on circuits and some stuff failed at 30 ft, We are first going to try to cut and polish our own cast acrylic domes for the ends, and a ring for the waste cameras and seal with o-rings with backing rings. I'm very intrigued by the work you've done. And hope you'll share more of it. My email is svseeker@ymail.com or your welcome to post to the SV Seeker group on FaceBook. Thanks Doug

Look at impeller including a long shield. I know there is a different name for the cone shield around the blades

hey guys.. what digital scale did you use to test the thrust when tank testing?

@SVSeeker

8 жыл бұрын

+DRay Construction I just got two different digital fish scales. I check them against each other and they were only off by .2 oz.

Ceramic bearings are available from bocabearings for many RC parts. That might avoid the corrosion issue on the bearings. And rather then potting the motor, a simple extra coating by dipping might be sufficient for your use.

@SVSeeker

10 жыл бұрын

That's I'll look into that.

Good project, might consider ceramic brgs.

The bearing in the donkey is likely an oil filled bush, possibly phosphor bronze. You can buy the stuff cheaply online and machine it for the other motors you have a preference for on size.. just pop out the bearings and machine some phosphor bronze and push fit it in there, job done.

but what happens if you get a air bubble in your potting at that depth it could blow due to the pressure, in you thruster motor which could cause failure ? or is your potting able to withstand that ?

@SVSeeker

10 жыл бұрын

Nothing happens. The motors will actually run fine in seawater even if you do nothing to them. The potting is just to add some protection to the lacquer that protects the copper windings. Sand and salt would otherwise eventually wear the lacquer off and cause a short. Pulling a vacuum helps insure the potting material more completely fills the voids.

@SuperBlackWolf1991

10 жыл бұрын

I see well thanks for the info

Liquids are incompressible (the reason they are used in hydraulics) so fill your gear with mineral oil and pressure problems go away it's also non conducting (see oil cooled PC). If you want to fill the bearing voids with oil use a vacuum device (see pressure pot on ebay) to first evacuate the air from any potential voids and re-pressurize in a mineral oil bath so the oil is drawn into the voids(may take a few days), a cheap high vacuum pump is a fridge compressor. The engines are PWM speed controlled so you just need to set a sane speed and the blade pitch ceases to be such a big deal and heat dissipation is trivial in water. The only device you potentially can't protect from having an air void is the camera as a normal lens system is designed to work with an air boundary refractive index, if you can find a clear mineral oil you could fill the camera voids with that and try refocus also distilled water is non conductive and I would guess with a lower refractive index than oil so placing the camera in a water box may work, for a while anyway. I guess this project is already finished so this is advice is probably meaningless.

@capcadoi

9 жыл бұрын

I filled the motor housings on my rov with siliconic oil, perfect for keeping rubber seals in good shape, and also doesn't conduct heat. I went to test it out on a lake, and the low temperature made the oil so viscous it barely moved. Also, after being that cold, the oil changed its properties and started interfering with the brushes on the motor. So...be careful with filling with oil.

@TheShorterboy

9 жыл бұрын

Capcatrei You can use anything that doesn't conduct including distilled water, white spirit,alchohol,terpentine or kerosine.

@capcadoi

9 жыл бұрын

TheShorterboy "Anything" is also silicon oil, which lubricates the motor and maintains the rubber seal - BUT that failed miserably. So "anything" doesn't work until you tested it and made sure it has no side effects.

Hi, And so many thanks for all your hard work making and uploading all these videos! I just wondered where you have used wax as a potting agent, it is used pretty universally in guitar electronics, though I don’t know enough about any ‘moving’ pieces using wax.

@SVSeeker

8 жыл бұрын

+mrbluenun I have used a mixture of wax and polypropylene plastic which raised the melting temperature of the wax to about 180F. A 6x6x4 block of it around relays worked well for about 1 year outdoors and then then heating cooling cycles caused it to crack.

@mrbluenun

8 жыл бұрын

+SV Seeker Hi, Thanks for your reply. I wonder whether you would be interested in the wax use still, perhaps making the wax less likely to crack using bandage wrapped around the wax itself. Have you tried the wax alone with no plastic?

@SVSeeker

8 жыл бұрын

+mrbluenun Perhaps. For my particular use I had to raise the melting temperature otherwise the sun would have melted it out for me.

where did you get these $12 motors

@SVSeeker

7 жыл бұрын

HobbyKing

hi how does salt water effect rc brushless motors ? does it cause lots of damage ?

@SVSeeker

5 жыл бұрын

I think you absolutely have to change out the ball bearings for bushings, but otherwise I saw no problems after repeated test and I never even bothered to give them a rinse in fresh water.

@bruhmettinmomentogullar4215

5 жыл бұрын

many thanks @@SVSeeker

Liquid propellers usually spin much slower than air props. Judging by that you are going to most likely want the lowest KV motor you can find to reduce the current draw. I am sure you have already figured that out though because this video is a few months old. Check out some motors meant for multirotors. They come as low as 100kv.

ethel methel keytone poroxide. that is what the windings should be covered with

check out the small propellers they where on their legs! this is what you need! GoPro HD: Shark Riders - Introducing GoPro's New Dive Housing

@SVSeeker

10 жыл бұрын

Yup, something like that.

@Brad1962Fisher

10 жыл бұрын

hoping you have a happy and healthy New Year in 2014!

Whaaa??? Those motors need no protection? That is spectacular! I need to get my hands on some of those. Thanks for the info. :-) Now, lets see... who do I know who's coming to Panama and has space in their luggage....

@SVSeeker

8 жыл бұрын

+J Mantzel Hello Jaimie. Love what you are doing and what you represent. Hope to meet you on the water someday.

Could you possibly link me to the motors you ended up using? There are lots of d2830's... :)

@SVSeeker

9 жыл бұрын

Motors are constantly changing. Either of these will do fine, depending on how much power you want. And there is a fantastic 3D Printable propeller and shroud in the Files section of our FaceBook group "SV Seeker" facebook.com/groups/svseeker/ www.hobbyking.com/hobbyking/store/__16229__NTM_Prop_Drive_Series_28_30A_750kv_140w.html www.hobbyking.com/hobbyking/store/__19611__NTM_Prop_Drive_28_36_750KV_265W.html

@DukeReduker

9 жыл бұрын

SV Seeker Thanks for the help, love this series!

Happy New Year

@SVSeeker

10 жыл бұрын

Best Wishes for 2014

surely ball bearings, that's typically what will take an axial and radial force, 99.9% certain

That donkey motor looks to have sintered bronze bearing sleeve, should be felt washers too, it's a bronze that soaks up oil from the felt Also, rather than potting the motors, how about a good marine varnish, or enamel varnish (like the wires are coated with) should allow more heat to escape.

@SVSeeker

10 жыл бұрын

I thought that too, but on close inspection, it's not sintered. Interesting Idea about the varnish. Any idea what the W/mK number is for winding varnish? I may be reading this wrong but the potting compound at .6 looks better than varnish. www.lakeshore.com/Documents/LSTC_epoxygv_l.pdf

@SVSeeker

10 жыл бұрын

SV Seeker I think this is the stuff I ordered: www.digikey.com/product-detail/en/832TC-450ML/473-1089-ND/655660?WT.mc_id=IQ60891366-VQ6-34081019475-VQ16-c&wt.srch=1&wt.medium=cpc&WT.srch=1&WT.medium=cpc

@NuttyforNissan

10 жыл бұрын

I agree about the varnish, and using the donkey.

@sparkyprojects

10 жыл бұрын

SV Seeker I'm not too familiar with the numbers, but when you said about potting, that would imply a solid block, but varnish could be just a few coats as a protection for the windings and cores against sea water

@ToplessTattoo

10 жыл бұрын

NuttyforNissan I am with this guy. Why go through the trouble of the potting? Why not just run them till they die and replace?

Can brushless motors run in water?

@SVSeeker

6 жыл бұрын

Yes. 12v DC motors with brushes will work too, just not as well.

Ambient pressure at a given depth is calculated as; pressure = (depth (in meters) / 10) * 14.7 (1 atm). At 3000 feet the ambient pressure is around 1,350 psi. Perhaps you could pressurize the interior of the ROV's enclosed sections with compressed air or nitrogen to counter the outside pressure and increase your maximum dive depth. If your enclosed section could withstand 800 psi and you pre-pressurized to +800 psi at the surface than you could dive effectively to 1614.7 psi depth because the differential pressure would be less than 800 psi. This would enable your ROV to dive to 3,570 vs. only being able to reach 1802 ft if left at ambient surface pressure internally. Not sure if this is already done as I have no experience with submersibles although I've thought about taking on such a project in the past since I live 4 miles from the Gulf of Mexico and 6 miles from one of the best Marine research laboratories in the country... Also another interest of mine has always been to build a magnetometer array consisting of several spaced magnetometers on a boom which could then be charted to a waterfall graph on a computer sort of building a map of sub surface metal objects buried in the sediment. It would be an awesome capability and maybe an interesting side project for your ROV or as a tow behind for your boat once you get it up and running.

@SVSeeker

10 жыл бұрын

Towing a similar unit behind our boat is the motivation. The internal pressure idea unfortunately does not work well with electronics.

@Prometheus203

10 жыл бұрын

SV Seeker Alright thanks, here are a few links I found while catching up might be useful if you haven't already seen these. Really cool: colin-ho.com/research/msled/ From Colin Ho, designer of above: "I've used mineral oil, silicone oil, and flourinert as pressure compensation fluids for high pressure electrical compartments. Mineral oil works well but is really messy and not fun to clean off for maintenance. Flourinert is nice, but really expensive and is about 1.8x the density of water (so its really heavy). Currently I'm using silicone oil, its cheap, not as messy as mineral oil, and flows better (so you can get air bubbles out easily) This liquid compensation technique works because of the fact that all liquids are pretty much incompressible. Thus by filling a compartment with a non-polar liquid (so that it isn't conductive, and it doesn't mix with water) you essentially eliminate the pressure differential between the internal compartment and the external environment. A lot of commercial deep sea thrusters use this method; its typically called things like 'oil-filled' and 'pressure-compensated'. I used this technique in the tail section of this underwater robot, and we pressure tested it to 1.5km of depth without any issues. Since there isn't any pressure differential, the electrical compartment doesn't have to be terrible structural! (in our case we machined the tail section out of marine grade delrin). But there is one design consideration that must be added; you have to have some sort of flexible diaphragm to allow for the liquid in the compartment to change in volume. All liquids are 'essentially' incompressible, but they still slightly compress at high pressures. So you accomodate for that volume difference, and ensure that there is no pressure differential, you need to have some sort of flexible diaphram for the compartment." Pressure tolerant electronic component types: en.wikipedia.org/wiki/Pressure-tolerant_electronics DIY 100A, 30V ESC: www.rcgroups.com/forums/showthread.php?p=8056614#post8056614 Controlling a brushless motor with Arduino via ESC: dronesandrovs.wordpress.com/2012/11/24/how-to-control-a-brushless-motor-esc-with-arduino/

FYI, you could always use a cheaper speed control with only forward then use a DPDT relay to get your reverse. Just another option. ;)

@SVSeeker

10 жыл бұрын

Yup, that would work.

The motor, being in the water, won't need additional cooling. The ESC will need cooling. They do make some for boats with water cooling, but I'm sure they aren't any good being open to extreme high pressure.

@SVSeeker

10 жыл бұрын

Right. We need some way to connect the heat Sinks on the ESC to the aluminum hull of the ROV. But it will have to be able to be connected and disconnected back inside a 3 1/2" ID pipe that is the hull. Filling it with oil would work, but we need the positive buoyancy.

@T3andChris

10 жыл бұрын

***** Love the episodes. Happy New Year.

Looking forward to this project there are lot's of schematics online :)

@SVSeeker

10 жыл бұрын

The goal is to keep it to COTS (Consumer Off The Shelf) components as much as possible so that it is easy for others to replicate. Current thinking is that the control will be done with Arduino.

@wanabear5716

10 жыл бұрын

Ah no problem Arduino will be good fun and a learning process..Will it be all controlled through arduino while it's underwater.I suppose it will all be hardwired any way..Good luck,I am looking forward to the rest of the project..There is so much you can do like programming pic chips and add bluetooth bee :)

if you have any questions about anything RC talk to Bruce Simpson from Xjet kzread.info

Even tho the brushless motors wont short circuit they will corrode. So the bearings will be scrap pretty fast from corrosion and salt and the anchor and magnets will corrode and collect salt deposits, etc and aluminium also corrode in sea water so the housing will also corrode. I think you should water seal them or at least suspend the whole motor in some thick oil. Even tho they are cheap you will get tired of replacing them after a while. A good way to water seal them without having to have high pressure seals is to make a magnetic coupling. Then the axle wont pass through the housing at all and it is much easier to seal a closed box then one with an axle going through it. For this the housing should be of a non magnetic material like plastic.

@SVSeeker

10 жыл бұрын

I've not seen a mag coupler that looked like it could survive 1700 psi. The oil compensated idea is on the table, that might be easier with an inrunner or servo motor. And we have a tank of seawater so we'll be testing the life expectancy. Good Ideas there.

@meocats

10 жыл бұрын

SV Seeker I think there's a way to prevent corrosion, by attaching a piece of zinc (i don't remember, am on shitty laptop, hard to google), that act as an electron doner. instead of the copper donating the electron.

yes they are ball bearings ss I do believe as well

@SVSeeker

10 жыл бұрын

Thanks!

You can buy your own self-lubricating bearings for your motors, they look like a brass bushing, and the material is extremely inert so maybe it will resist sea water. Frelon liner on these bearings (from PBC bearing) is extremely inert, even under heat.

@SVSeeker

10 жыл бұрын

Interesting. Do you have a source for these in very small sizes?

@meocats

10 жыл бұрын

SV Seeker am not affiliated with pbc, but pbc has them in 3/16" ID. The wear surface is made by frelon entering the rough surface micro-grooves. This mean two thing: frelon-on-frelon contact causing low friction (and long life), and the surface can't be less than 8Ra surface finish. See here; v=aD224gX39G0 . I would ask for one as a sample, say you're looking to buy like 5000, they'll give you one as a sample. Then you can set up a motor with it, and have it run in a bucket of water continuously for like a week. Throw in some salt, cornstarch and mud and see what happen. Am not sure if you're asking for a source in smaller ID than that, or maybe the supplier you called don't carry small size=?

@meocats

10 жыл бұрын

meocats teflon bushing of course too, highly resistant to everything except strong fluorinating agents. Teflon can be found in frying pans, can be found in the tips of those little suction pumps you use to absorb extra solder when desoldering microchips. If you have one of those (they're like 5 dollars anyways) in your shop you can test it right now. Inner diameter looks like 1/16th. If looking for smaller or odd size inner diameter, I think you can just buy a stick of teflon, drill and ream it, on the lathe. Am hoping its cheaper since its more common than frelon.

Potting can be made thermally conductive by the addition of fine aluminum oxide powder as filler. I would think a silicone would be a better potting resin than polyurethane. Google Alumilite or Smooth-On for supplies.

@SVSeeker

10 жыл бұрын

Thanks Bob. Thats a great idea. It would make it electrically conductive too, but we could start with a layer of mg Chemicals Encapsulating Epoxy, followed by copper or aluminum powder infused resin.

@TDKSuramar

10 жыл бұрын

SV Seeker Actually, solid aluminum oxide is non-conducting and highly thermally conductive. Alumina is a common component of heat-sink grease. Dow Corning makes such an encapsulant for electronics which is only available through industrial suppliers, however, making a homegrown mix is simple enough. en.wikipedia.org/wiki/Aluminium_oxide www.dowcorning.com/applications/search/default.aspx?R=527EN www.amazon.com/Aluminum-Oxide-Powder-sturdy-plastic/dp/B00BM8KCXY/ref=pd_sim_sbs_indust_5

You might enjoy "6x03 Torpedo" from tv's junkyard wars. on KZread.

Hi Replace the bearings with Oillite bearings

Most of those tiny bearing use steel balls. If you are lucky they are stainless steel. A couple of dunks in salt water and they will be scrap. Worse, the motor cores are iron. They will corrode even faster. Your only hope is immediately rinsing the motor with fresh water and then storing it in light machine oil. You can buy the varnish they put of the wires. It is call transformer insulating varnish (eBay). I don't know that it will help with heat transfer, but it can handle high temps. I don't know how it handles seawater. It does require baking. What you really need is a planetary gear box to reduce the shaft speed and give you more torque for those bigger propellers.

@SVSeeker

10 жыл бұрын

We'll certainly see. I know it will take more than a couple of dunks. There is a guy, Anthony in the UK that did months of testing with no noticeable problems. A fresh water and then oil bath is a good idea. I'm told they have great technicians of the boat for that kind of work.

Just as a idea, to maybe investigate, check out, EDF Units, although they are made for one direction airflow, the system can be adapted for your needs: hobbyking.com/hobbyking/store/__681__58__Hardware_Accessories-EDF_Systems_Parts.html Cheers JT

Have you considered the possibility of use magnetic coupling? The the motor could be protected from salt water. Its just one idea...

@SVSeeker

9 жыл бұрын

Maurício Leao We did. But it's considerably more complex to build and seal a housing for 2000 psi and the results are too bulky for the application.

@mleao

9 жыл бұрын

SV Seeker Another thing i was thinking is: why don't pressurise inside the ROV with a rubber bag or a chamber with where the exterior pressure equalizes the interior until the limit of operation of the equipament...

@SVSeeker

9 жыл бұрын

Maurício Leao Because you'd have to build the seals so they could take pressure from both sides.

@mleao

9 жыл бұрын

SV Seeker not exactly, a rubber bag exposed to environment and connected to the ROV, would be squeezed, pumping air to the ROV, then the presure into the ROV would be partialy equalyzed with environment. The volume of the bag limits the presure max inside ROV. Regards from Brasil.

@mleao

9 жыл бұрын

SV Seeker may be a fluid instead of gas being transfered from the exterior rubber bag.

I have tried to send a personal email to you SV Seeker but it keeps asking me "Please enter a valid email address in the email address field". What email address field??Randy

@SVSeeker

8 жыл бұрын

+Randy Howard My email is svseeker@ymail.com

What about repurposing some old PC cooling fans. They're super cheap and you can get them in all sorts of different pitches.

@SVSeeker

10 жыл бұрын

I've seen the blades used but the motors are very low wattage.

@jepps77

10 жыл бұрын

SV Seeker Yeah, you wouldn't want to use the motors at all. But the blades might be helpful since they come in all sorts of sizes, pitches, no of blades etc.

in my opinion the best people to talk to about this sort of stuff would be the flitetest guys josh and josh, im sure they would be open to you bouncing some ideas off them and i think they are sponsored by hobby king. kzread.info Yes i know they are a flying channel and these motors are for a submersible but they really know their stuff, just a thought

Why not go with stepper motors? Replace bearings with bronze bushings. Fill with mineral oil and put o-rings on shaft. Low speed and high torque. Less worry about cavitation.

@SVSeeker

10 жыл бұрын

That's not a bad idea. Gear heads too. I think they would be best in an oil compensated housing so there is no torque loss at the seal and less chance of flooding. Turning a big screw gets lots of power. But the unit is towed 90% of the time, so too big of a screw might be too much drag. I don't know anything about their efficiency. We'd want the highest thrust/watt number we can get. Have you any more thoughts about it?

@DavidKirtley

10 жыл бұрын

SV Seeker Assuming it is tethered, let it generate power when towed? Cowling when stowed? The slower brushless motors would be better but not in keeping with cheap and replaceable.

@thecorbies

10 жыл бұрын

David Kirtley Nice idea about the motors generating power when towed. Unfortunately, the energy required to turn the motor/prop would have to come from somewhere and that somewhere would be the towing vessel motor(s). Of course I realise that we're talking small numbers with these motors and there may be a certain economy of scale in using the towing vessel motors to generate the 'new' power, but remember the 'new' power doesn't just miraculously come out of the ether. It is all to do with the conservation of energy.

@SVSeeker

10 жыл бұрын

thecorbies Right, we considered that too. But the towing speed is only 3.5 knots and the specs are to keep the drag to a minimum.

@DavidKirtley

10 жыл бұрын

thecorbies Hopefully, those big sticks with cloth on them will be generating most of the propulsion with power to spare. :) Seriously, that is the way many sailboats are going with electric propulsion and charging off the prop spin while sailing. I don't know why more people don't put another pulley on the shaft and just put it in neutral and run a generator off of the prop as "extra" power. Sure puts out more power than solar panels.

Servo planetary gearbox www.servocity.com/html/planetary_gearbox.html "A highly versatile system for reduction of high RPM electric motors to high-torque low RPM applications."

@SVSeeker

10 жыл бұрын

Thanks for the link.

Did you look on youtube? This link was just on the right ------------------> kzread.info/dash/bejne/loCTl7eep7K_eaQ.html

do you know what use men with super giant hands call those tiny clips that hold those tiny motors on the small shaft? we call them Jesus clips as in Jesus where did the dam thing go! Lord help me find it!

@SVSeeker

10 жыл бұрын

LOL! Yeah. You'll notice one of those motors is missing it's clip. Somewhere on the shop floor with all of the drill shavings. :)

@Brad1962Fisher

10 жыл бұрын

I keep a old drink cup on the bench by my tool box that is half full of those (Jesus) E clips as I save every single one I ever remove from all the carburetor I had ever rebuilt (Car, Truck Lawnmower etc. and transmission) just for that occasion! I also learned to sweep the floor around the vice before installing u-joints into drive shafts as those needle bearings are not all the same size! :-)

One of the constant draw-backs of this type of motors is the lack of power before they reach at least 5% of their practical RPM.. I imagine that you already have the bad experience of founding that there is literally no power under water! but if you give them a small gear box, with a 15- to -1 you will have power to spare and a long life battery! because if you use them as you have them there... you will find your self with a swollen battery, ant no power what so ever!!

@SVSeeker

9 жыл бұрын

Actually we are pushing over 4 pounds at 120 watts. Watch the rest of the videos.

@Migueldeservantes

9 жыл бұрын

SV Seeker It was just a very humble advice since I use this motors all the time, because for the same power output you may be able to get well over 15 to 20 pounds if you use the gear reduction.. you may not brake any speed records but in that way you don't over tax the ESC.. but if you already resolved your problem please disregard my message. I honestly wish you luck.

I feel the strong need to add my pessimism regarding the life span of these motors in sea water. As far I my experience with both RC Motors and marine environments goes: This is a particularly bad idea. The motors use aluminium and some iron based materials next to copper. (A brilliant recipe for a galvanic cell by the way.) All these will not stand sea water and I’d guess you’d feel the damage quite fast. A regular 12V motor e.g. in bilge pumps usually die within a week in sea water (idle) or within hours (when operated). The bearings and the copper suffers most from the contact. I’d strongly rethink this design. Get the mechanics and electricity as well sealed from salt water as possible

@SVSeeker

10 жыл бұрын

We will find out. Stay tuned.

@Sqeezerful

10 жыл бұрын

SV Seeker When you do testing in the "sea water" tank, take temperature into account. Salt water seems much more nasty when warm (as in the tropics). A week or so in these waters will make antifouling a necessity. I’d particularly avoid copper aluminium compositions in sea water. You can sink an aluminium boat rather quickly by tossing a wet coin (containing copper) in the bilge. It will corrode through the hull in no time, The varnish on the wires just protects the wires against a physical contact. It just does that as a pantyhose would do. The wire gets coated before the winding hence minimal cracks in the coat are unavoidable in manufacturing. The point is this isn’t water tight. Maybe you can measure the creepage current from the windings to another metal object in the water etc. That will reveal uninsulated spots.

Guys, what about corrosion? I started building my own hobby sub as I am controls and mechanical engineer, I find it a great challenge. However everytime I see someone using anykind of motors directly in the water, without proper sealing, it gives me shivers. Whats with that, help a fella here :D Thanks!

@SVSeeker

5 жыл бұрын

Stop wringing your hands and try it.

@AljazJelen1992

5 жыл бұрын

@@SVSeeker I cant just try couple of times to get repetitive result to achieve robust submarine. It costs too much

openrov.com/ Thought you might find that interesting or get some inspiration. Not so good for your current deep sea project, but maybe for an ROV for Seeker.

@SVSeeker

10 жыл бұрын

Thanks. Been following them for a while. homebuiltrovs.com is another good source.

I wouldn't be getting into flex shafts or gearboxes or anything like that. Design a propeller to fit on the outside of the donkey with a nose cone over the front and get it 3d printed. It shouldn't be too hard to calculate the pitch, size and number of blades of the screw. I don't think it would have to be very big. My guts telling me that the blades would only be maybe 3/4" beyond the Donkey's can. I'm also thinking you might want to look for motors with an even lower KV rating and design the prop to have lots of blades. I'm assuming this ROV is going to move pretty slow and your looking for static thrust and not high speed. The power ratings are pretty meaningless in this application because water is more conductive of heat than air. It still gives some relative numbers That said you also want to have water flow over the coils to keep them cool. I guess it will boil the water long before the varnish starts to come off. The power ratings are the point where the varnish doesn't burn in air. This is also where the current rating comes from. The propeller design is going to determine how much current the motors draw. Too large of a propeller and its going to burn out the speed controller. The motor timing is also going to need to be tweaked. Where there isn't much feedback in the controllers at low speeds the motor will skip. Once concern I have is how to keep water from working its way into the wires going through the hull.

@SVSeeker

10 жыл бұрын

Thank you Chris, That is a we'll thought out reply and good blade idea for the Donkey. My only concern is the impact on drag that those motors might have, but it should be be easy to measure. And you're right about the wiring, the insulation acts like a pipe line for water. The trick is passing the conductor through the hull as a solid copper pin potted in an epoxy filled cone shaped hole.

They're OK in fresh water but don't try them in salt water without waterproofing!

@SVSeeker

3 жыл бұрын

Bull Shit. I tested them for weeks in salt water. They work fine.

@lstein3372

3 жыл бұрын

@@SVSeeker They must have some waterproofing built-in then. Electrolysis would eat your electrical connections otherwise. Were they running for weeks in saltwater? It's the electricity that causes the problem.

@SVSeeker

3 жыл бұрын

@@lstein3372 I've done the testing. And you are welcome to watch the videos.

@lstein3372

3 жыл бұрын

@@SVSeeker I am watching the videos, but in chronological order, I'm currently at Oct 2014. I'm also a retired electrical engineer so know something of which I speak. RC motors are usually water resistant so they can be used in the rain. So they do have some resistance already built-in. I'm not concerned about the motors themselves. I'm concerned that the electrical connections will corrode prematurely by electrolysis if there is a path between them through the saltwater. Which wouldn't be an issue in freshwater.

@SVSeeker

3 жыл бұрын

@@lstein3372 Right. You have a piece of paper and I have experience. : )

It seems that you have a great project and it will be great to follow your build. If it helps any I have been getting shafting and hubs from this site for awhile and it helps save time with machining www.servocity.com/index.html

@SVSeeker

10 жыл бұрын

Thanks for the link.

Recycle! Not toss overboard!

www.harbormodels.com is a good place for props