MicroSeeker Thruster Design

The new single thruster design for MicroSeeker is shown in detail on this page. You can click on any of the pictures for a larger version.

Okay, here's a picture of the thruster attached to the sub, with the propeller still attached. The prop is a Graupner 6-4", which means it is 6" in diameter, and has 4" pitch. I had to mill an area in the center of the prop to fit it onto the threaded shaft I had, and I have a small brass insert to reduce the size of the center hole from 3/16" to 4mm.
Here's the thruster, minus propeller and nuts. The shaft is a 4mm stainless steel shaft, threaded on one end, which I bought from a local hobby store.
Here's the thruster removed from the thruster tube. The black cone piece is machined from a single piece of 1.5" black Delrin, and the white disc is a piece of machined white Delrin rod.

The motor is a 12 volt gearmotor, and turns about 600 RPM. I bought the motor from a Canadian robotics company, RobotShop.

Here you can see how I attached the black thruster end-cap/cone to the white motor mount disc. The motor mount disc is attached to the motor using #4-40 machine screws, and it has a 1/2" hole through the center to clear the motor shaft and coupler. I have a small ball-bearing on the shaft, immediately in front of the coupler.

The disc also has two 1/4" holes to fit the brass inserts on the end cap, and holes through the side (which continue into the brass inserts and are threaded there) to hold the end cap snugly against the motor mount. The brass inserts are glued into the end cap.

The o-ring split when I took it apart, but its fairly simple to glue it back together again (I build the o-rings I use from a kit).

And here's a final picture, with the motor mount disc removed. The coupler is a piece of 3/8" brass rod, with a 4mm hole center-drilled through it, and a pair of #4-40 holes at each end for set screws.

You can also see the seal I used in this image, which was purchased from SubConcepts (although their web store seems to be gone now). They import the seals from a German company.

Here's a really big (442 KB) version of this image.

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Questions and comments can be sent to Jon@huv.com