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The Unofficial all things Jet drive thread

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The Unofficial all things Jet drive thread

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Old 02-14-2017, 11:30 AM
  #5001  
volusia
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I have taken delivery of a nesew jet drive unit and brushless motor, my question is this- what would be the perfect size for a jet boat hull based on the following,- 50mm impeller jet drive, 5694 SSS brushless motor, and 250 amp Alien speed controller that is rated up to 8S.
I have not as yet purchased any lipos as basically I do not have the knowledge for that choice at present
I plan to build the hull from scratch from timber with a view to perhaps creating a fibreglass version later.
The motor is 800kv and is also rated up to 8s.
Any advice would be appreciated as I am a newcomer to fast electric boats. (normally build scale boats).

Regards

Steve
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Old 02-14-2017, 01:34 PM
  #5002  
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Well, I wouldn't call jet boats fast boats but they sure are fun in creeks and shallow water. That is a good setup you have there - I would put it in a 36-44 inch boat for good speeds.
I would run that 800kv on 6S lipos which amounts to 17760 rpms' - a good top end for a 50mm impeller. You can push that, but the amps would jump up quickly with that big motor (but try it briefly on 7S to see if it goes faster or just makes more noise).
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Old 10-22-2017, 07:15 AM
  #5003  
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Hi there its been some time since but I'm planning on (re-)starting a new project. I'm sitting an old set of 32'' RHIB molds I made years ago and was thinking using them once more for making a fresh couple of hulls.

Hull mold has had a new stern plate added. Deck mold will have to be partly redone to have a flush deck.

Plan is to produce 2 boats; 1 will have a single 28 mm Graupner jetantrieb 2
(one of the used GR2344 that I took from the old model) coupled to a 6S 1300 W 33K Heli motor that should deliver approx. 900 W @ 4S doing 22K and the other will have twin Graupner mini's ( GR2349) that should deliver 2 x 350 W @2S doing 19K tpm or 2 x 550 W @ 3S doing 29K.



All theoretical of course.

Pics show preps for the single drive; added the new sternplate to the mold, and made a removable insert for single drive footprint including triangle; there’s an old picture of the original model and a couple of the jet with new carbon mouting-adapter for the stern that enables the jet to sit further back in the hull. A mold for producing a Hamilton style bucket is in the making aswell. The reason for the relative small triangle in front of the jet is just that it smoothly follows the extended curve of the roof of the intake-channel of the jet. To me, that should give the best performance.

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Cheers Haje74

Last edited by Haje74; 10-30-2017 at 01:32 AM.
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Old 10-23-2017, 07:34 AM
  #5004  
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Haje I really like the design of that hull. I will be watching this build closely. If you ever decide to sell your hulls, let us know!
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Old 10-23-2017, 09:49 AM
  #5005  
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If that happens you can be sure you’ll know about it Sundogz!
Yeah I think the hull design worked out nicely on this one.
Actually quite sleek, not as stubby as most Ribs/rhibs are.

Best regards

Last edited by Haje74; 10-29-2017 at 10:38 PM.
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Old 10-28-2017, 11:24 AM
  #5006  
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Another project I’ve been working on is a 1:7 scale model of a Dutch Valentijn-class Lifeboat.
This model is big: 60 inches or 1.5 m long and is to be powered by a Blata 50 driving twin upgraded China waterjets thru an MHZ-gearbox.

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Last edited by Haje74; 10-30-2017 at 01:30 AM.
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Old 10-28-2017, 11:29 AM
  #5007  
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The jets have been upgraded by changing the steel ball bearings on engine side for SS-Ceramic, and the tailbearings for sintered bronze. Also I’ve added grease-nipples to both stator and bearinghousing to be able lube all bearings without dismantling the units. Finally the bearinghousing towards the engine has an SS reinfocement-ring added to toughen up the housing a bit. They turned out very nice so I’ll post some pics of ‘em tomorrow.

Last edited by Haje74; 10-28-2017 at 07:35 PM.
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Old 10-28-2017, 12:54 PM
  #5008  
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Yes, common lube port is smart. Looking forward to seeing the pics of the pumps.
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Old 10-28-2017, 09:29 PM
  #5009  
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Default Upgraded 54 mm China Jetunits

Here’s some pics of the units.
I think they turned out pretty nice

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Sorry guys but I cant seem to get the pictures pop up correctly..?

Last edited by Haje74; 10-30-2017 at 12:45 AM.
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Old 03-29-2018, 02:59 PM
  #5010  
sharpy22
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Default Hey haje74

​​​​​​was Wondering what China pumps those are and where they could be purchased at, they look like hobby king pumps


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