[PSUBS-MAILIST] Water jets
Alan via Personal_Submersibles
personal_submersibles at psubs.org
Sun Oct 26 16:34:49 EDT 2014
When I was having lunch at Nuytco, I was told that
Hawke's flying sub went upside down on the surface
& couldn't be righted by the pilot. So something else to
consider.
Alan
Sent from my iPad
> On 27/10/2014, at 9:25 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Alan,
> Not much roll when you have a couple thousand pounds of ballast. I light low volume sub might get some roll.
> It would be a bugger to get into at the surface though. Maybe leave the rolling for airplanes.
> Hank--------------------------------------------
> On Sun, 10/26/14, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> Subject: Re: [PSUBS-MAILIST] Water jets
> To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Received: Sunday, October 26, 2014, 4:14 PM
>
> Hi
> Hank,Graham
> wanted to rotate his jets separately so he
> couldget a roll / flying
> type motion. So he would need to havetwo
> separate intakes that rotated identically to the vertical
> outletsto
> acheive that without getting the forward motion &
> addedinefficiencies.
> I wonder what sort of roll you could get with
> aconventional
> set up.You
> must have tried that Hank / Alec. Do you get much of a
> tiltwhen you
> have your vertical thrusters working in
> differentdirections?Alan
>
> From: hank pronk via
> Personal_Submersibles
> <personal_submersibles at psubs.org>
>
> To: Personal
> Submersibles General Discussion
> <personal_submersibles at psubs.org>
>
> Sent: Monday,
> October 27, 2014 8:57 AM
> Subject: Re:
> [PSUBS-MAILIST] Water jets
>
>
>
> Alan,
> I did
> not think of that, but your right. You could put a shroud
> over the inlet that is inline with the discharge so then the
> pump is pulling and pushing.
> Hank--------------------------------------------
> On Sun, 10/26/14, Alan James via
> Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
>
> Subject: Re:
> [PSUBS-MAILIST] Water jets
> To:
> "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Received: Sunday, October 26, 2014, 3:50 PM
>
> One
> problem
> I can see is that if you have your Jet
>
> suckingwater in
> from the front & you
> pivot your outlets to get
>
> verticalmotion,
> then you will get forward
> movement from the suction
> ofthe inlet
> at a similar rate.Also I
> did
> a bit of research on jet propulsion a couple of
> weeks back&
> what I read
> said it was inefficient compared to conventional
> propulsion.Alan
>
> From: Alec Smyth via
>
> Personal_Submersibles
> <personal_submersibles at psubs.org>
> To: Personal
> Submersibles
> General Discussion
> <personal_submersibles at psubs.org>
>
> Sent: Monday, October
>
> 27, 2014 8:11 AM
> Subject: Re:
> [PSUBS-MAILIST] Water jets
>
>
>
> I
>
> don't think water jets are necessarily inefficient,
> but
> if there is considerable piping around
> of the water before
> it exits through the
> jets, that's what I was referring
> to.
> However, even that was not meant as criticism, it is
> just a normal trade-off. It is surely less
> efficient than a
> conventional
> direct-coupled prop, but you also get
>
> entanglement-resistance and maneuverability.
>
>
> On Sun,
> Oct 26, 2014 at
> 10:11 AM, Marc de Piolenc
> via Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
> There is
> nothing inherently inefficient about
> waterjets. There are
> commercial fast
> ferries using them and getting very good
>
> thrust per horsepower - better than any supercavitating
> propeller could do at the same speed,
> certainly.
>
>
>
> Lousy design will of course
> produce poor results, and jets
> are much
> less amenable to rule-of-thumb construction than
> open propellers. But whether it is "well
> known" or
> not, good design will
> produce good results.
>
>
>
> Marc de Piolenc
>
>
>
> On 10/26/2014 8:41 PM, hank pronk via
> Personal_Submersibles
> wrote:
>
>
>
>
> Graham,
>
> In the world of marine jet drive it is well
> known that jet
> drive takes two times the
> horse power to do the same job.
> Jet drive
> is well suited to a craft that needs a shallow
> draft. I think you will find it very
> complicated to
> control and it will be very
> inefficient. I have been down
> this road, I
> love the concept but abandoned it. If you go
> forward may I suggest you start with a jet
> drive. It is
> not a simple part to
> replicate. The impeller tolerances
> are
> critical. I have a jet unit on the shelf I could
> donate to your project. The jet is from a
> jet ski. I would
> consider a single rear
> motor on a full gimbal.
>
>
> Hank --------------------------------------------
>
> On Sun, 10/26/14, Graham
> Bayliss via Personal_Submersibles
> <personal_submersibles at psubs.org>
> wrote:
>
>
>
> Subject: [PSUBS-MAILIST]
> (no subject)
>
> To:
> "'Personal Submersibles General
>
> Discussion'" <personal_submersibles at psubs.org>
>
> Received: Sunday, October
> 26, 2014, 7:39 AM
>
>
>
> #yiv9417249292
>
> #yiv9417249292 --
>
>
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>
> #yiv9417249292 Hi I
> am near the end of my build
>
> of my k350 and have started to look at new
> designs I
> am
>
> interested in building a flyer sub and have
> come up with
> a
>
> design which will include a vectored motor
> drive this
> will
>
> enable my flyer to hover and stop where
> ever I want. I
> have
>
> designed a motor unit which will drive a
> fan type
> propeller
>
> as an intake this will force water to the
> rear of the
> unit
>
> where it is compressed then it is
> forced into
> ducting
>
> which will take the water to four nozzles
> on the side
> of
>
> the craft. The nozzles are able to turn
> three hundred
> and
>
> sixty degrees both side are independent
> of one another
> so
>
> rolls will be achievable. The reason for a
> vectored motor
> is
>
> you only need one motor source and one
> power pack this
> will
>
> ease the maintenance and increase the
> enjoyment of
> using
>
> your sub. I am interested in the clubs
> thought of this
> kind
>
> of design. Graham
>
>
>
>
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> _______________________________________________
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>
>
>
>
> --
>
>
> Archivale catalog: http://www.archivale.com/catalog
>
> Polymath weblog: http://www.archivale.com/weblog
>
> Translations (ProZ profile):
> http://www.proz.com/profile/639380
>
> Translations (BeWords
> profile): http://www.bewords.com/Marc-dePiolenc
>
> Ducted fans: http://massflow.archivale.com/
>
>
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