Hi Tim,
You might be thinking of a Tesla turbine, a blade-less stack of discs that uses laminar shear to accelerate fluids through a pump. I've built a couple using plans I found online. Unfortunately, they're about 40% efficient, pretty poor for propulsion. As the pumped material ideally has a near-zero velocity at the disc surface, they were used for de-watering mines when filtration was difficult. A Tesla turbine pump could pass stones without any wear on the rubber-coated "blades".
Be Well,
Arby
From: Eric <ewdysar@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Wednesday, February 8, 2012 1:11 PM
Subject: [Electric Boats] Re: bladeless propulsion ?
Hi Tim,
I don't know any specifics about the jet drive that you're talking about, but the Dyson "fan" is a lot like a typical jet pump with an exotic nozzle.
"Calling the Dyson Air Multiplier a fan with no blades is perhaps a touch misleading. There are blades in the fan -- you just can't see them. The pedestal hides the blades...." So it is really a ducted fan with the prop (impellor) in the base.
I would very surprised to see objective test data that showed a water drive configured like that was more efficient than a regular prop drive at thrust values above 10 pounds or more. Though I could believe that it might work ok for a very low power trolling motor.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Tim" <haywardt@...> wrote:
>
>
> .... For shallow drive and in weeds I know of a patent on a small jet drive that was made for foldboats and canoes that worked like the Dyson blade-less fan. It was highly efficient and worked very well in shallow water and weeds. It might be worth resurrection.
>
I don't know any specifics about the jet drive that you're talking about, but the Dyson "fan" is a lot like a typical jet pump with an exotic nozzle.
"Calling the Dyson Air Multiplier a fan with no blades is perhaps a touch misleading. There are blades in the fan -- you just can't see them. The pedestal hides the blades...." So it is really a ducted fan with the prop (impellor) in the base.
I would very surprised to see objective test data that showed a water drive configured like that was more efficient than a regular prop drive at thrust values above 10 pounds or more. Though I could believe that it might work ok for a very low power trolling motor.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Tim" <haywardt@...> wrote:
>
>
> .... For shallow drive and in weeds I know of a patent on a small jet drive that was made for foldboats and canoes that worked like the Dyson blade-less fan. It was highly efficient and worked very well in shallow water and weeds. It might be worth resurrection.
>
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