[PSUBS-MAILIST] Thruster Test

[David Colombo via Personal_Submersibles]

Hi Alan, l never thought of using a ladder as a test rig. Was the thrust to
watt ratio the same base at different speeds?
David

On Wed, Dec 5, 2018, 2:03 AM Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Just did the first test on my latest brushless thruster version.
> I started with a Vetus bow thruster which is normally housed in a tunnel,
> but
> to simplify things I am testing several different propellors without
> nozzles first.
> I have a 10mm prop shaft & the various off the shelf props need either
> drilling
> out or sleeves made to fit them.
>    I was getting 38.5 lb. thrust from 1,152 Watts & 45 lb. off 1,694
> Watts, which
> is comparable with some commercial thrusters but not with others. Some
> manufacturers are quoting thrust per Watt figures I find hard to believe.
> Will see how the other props work.
>    Testing came to an end when the automatic pool cleaner (which I had just
> moved to the end of the pool) came down & knocked my prop off while I was
> jotting down notes. First swim of the summer finding the shaft pin. The
> prop
> was held in place more or less by the force of the prop thrust & a tight
> fit.
> Picture below is from left to right; load cell mounted on the vertical
> stationary
> side of black test jig, motor controller, 48V rectifier with oil
> compensator on
> top, grey load cel display, servo tester to control speed & laptop with
> Vesc Tool
> program displaying data.
> The oil compensator is just for the testing, a much smaller & different
> system
> will be on the sub.
> Alan
>
>
>
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