The Guppy

[scubersteve]

Here's the power jumper arrangement I mentioned.
You can also see the video connector.

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[scubersteve]

I had started making a styrofoam topper to encircle the top of the vertical thruster tube because I figured at 7.66 lbs that The Guppy would sink.
However after doing some calculations it appears that it will actually be bouyant by about .92 lbs.
(calculated off the main housing being essentially a 5"x13" cylinder with a 2"x5"cylinder cut through the middle of it)

I guess I'll just coat it with the plasti-dip and throw it in a pool to see what happens.

[scubersteve]

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I don't care for the plasti-dip as a rov coating.
It goes on too thin like spray paint and doesn't adhere very well.
Anyway, I did a little bathtub testing last night and didn't find any leaks.
Today I have to make up 13 ounces of ballast to get it trimmed out properly.

[scubersteve]

I made up my ballast weight and got it trimmed out pretty well.
Today I took it to my neighbors pool and got to test it properly.
From what I understand from the rc subamarine guys a 72Mhz radio system should be able to work as deep as 30 ft.
However when I took it deeper than about 3 ft it would function erratically.
I'm not sure if I just have junk equipment (it's Harbor Freight rc airplane radio system) or what.
Anyway, it worked pretty well on and just under the surface. It was pretty manuverable until the bow thruster stopped working.
I initially thought that one of my over-volted ESCs had died, but when I got it home and tested it, it ended up that I had burned out the motor. It was just a small dual-shaft motor I had laying around from another aborted project and I don't remember what voltage it was rated for. I took it apart to see what the failure was and found that the brushes were worn out completely. It was new when I installed it so I'm guessing it was probably a 6v motor or something and didn't care for the 12v I was feeding it.
So I got on ebay tonight and ordered 2 12v dual-shaft motors (gotta have a spare).

I also have an old 27Mhz 3 channel radio system that I'm going to try. Theoretically the longer wavelength should give me more depth capability.

It was cool for a little while...

[jpWA]

I suspect the lateral thruster on the bottom might create stability problems for that slick torpedo-shape if there is not enough ballast, hope it works though.

[scubersteve]

The lateral thruster seemed to work fine, but it's about the only thing that did.
I'm in the process of replacing the vertical and horizontal thrusters with brushless motors and switching the control system over to a
ppm-to-pwm converter and using a tether. I found some nifty new props too.

The danger in trying to build something as cheap as possible is going too cheap. (which is what I apparently did the first time around on this project)

I guess this is Guppy 2.0

I'll post some updated pictures soon.

[rossrov]

Hi Steve. I can relate to "going too cheap", but it does bring out one's creativity, necessity being the mother of invention, as is said, and it's pretty cool making something out of cheap parts and junk, even if it doesn't work as well as it would with more $$ and time.
I like the idea of the central through-hull vertical thruster, and found my own worked very well. Must confess I eyed off that plumbing fitting pic you posted. As to jpWA's concerns about the bow (and stern?) thrusters, if there is going to be any sort of small landing gear or other appendage below the hull, this will shift the centre of lateral resistance down so where the lateral thruster is at present might work out just about right. Here's taking through-hulls to the extreme http://scini.mlml.calstate.edu/SCINI_20 ... totype.jpg
http://iceaged2010.mlml.calstate.edu/scini/

Thanks for comment on my video BTW.

Ross

[scubersteve]

I like the look of your rov Ross. Why don't you have a build log going for it on here? I for one would like to see more of it.
That under ice unit you linked to was kinda crazy. As you said...taking through-hull thrusters to the extreme.

I really rather like my layout on this build with the through-hull vertical thruster and single horizontal thruster.
You can drive it like a car. Anyway, some new pics of my updated thrusters.

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[scubersteve]

Having to redo the Guppy...again.
The brushed bow thruster arrangement wasn't working out so I'm changing to a tank-drive setup.
I hope to have it back in the water by the end of the week.

[scubersteve]

Front view