1/6 scale Jetsprint boats and 30mm Jet drives

[mickieb49]

Hi Mike,
The plastic is ABS, if you want to stick something to it, I suggest you give the surface a rough up with sandpaper first then use some epoxy glue.
The impeller needs to have a downward angle to help keep the nose on the water, if it was flat, you will need to have a lot of trim pointing down.
I couldn't make the flange around the too much bigger as then it wouldn't fit on the bottom of the hull, I suggest you start with a smaller drill than necessary, then work your way up, this way you should be able to get the holes in the centre of the bottom flange.
It is a little bit too late to change the flange width as that Is a very costly change to the injection molds.
The new plug has been machined out yesterday, I am hoping to be starting the mold next weekend, then laying the hulls up very soon after.
Regards Mick

[mudboggin3]

What would a complete kit run and when can I get one.

[mickieb49]

What would a complete kit run and when can I get one.

A kit will be $275 AUD plus shipping, you will need to get your own electrics, servo and motor mounts. Mold is done on the new bottoms, I am hoping to get some time and polish up the mold, then lay up a hull next weekend, hopefully run it the week after, providing all goes well then I will start mass production of the hulls. Please be patient as I am a 1 man band, and between working full time, looking after 2 toddlers I do not get the 20+ hours in the shed I need to get everything done..
I have a few kits of the first version ready, they are on ebay at the moment, or you can wait.
Regards Mick

[Darin Jordan]

Mick,

Quick couple of questions... well... actually one request for confirmation and a question...

1) Am I seeing correctly that this jet pump unit has adjustable trim angle as well as nozzle steering?

2) What power range is this unit designed for? P-Ltd style system? What RPM's are recommended, or can it handle?

Thanks,

[mickieb49]

Mick,

Quick couple of questions... well... actually one request for confirmation and a question...

1) Am I seeing correctly that this jet pump unit has adjustable trim angle as well as nozzle steering?

2) What power range is this unit designed for? P-Ltd style system? What RPM's are recommended, or can it handle?

Thanks,

Hi Darin,
You would be correct, it has both steering and trim.
The Max rpm I have tested it to was 28000 rpm, I wouldn't suggest you go over that anyway, as it will start to work against itself by making too much back pressure.

On another note, the first of the new hulls is layed up, I should be pulling it out of the mold tomorrow, then give it a run next week sometime.
Cheers mick

[timjz]

Very nice work!

Quick question, would a true flat bottom (Dumas SK Daddle) hull still need a center skeg with a jet drive?

Also, would the 27" Dumas SK Daddle be better suited to this drive, or the 36"?

Edit: nevermind, just ordered the 27" kit & a jet pump!

[mickieb49]

Hi Tim,
The problem with flat bottoms is the side slippage causing turbulence into the unit on turns, will work just not optimum.

On a side note I have been busy with the new mold, I will upload some pics a little later on , basically the mold is done and I am progress in getting the hulls built as quickly as it will allow.
I have been researching into getting the hulls manufactured in ABS, and it looks like I will be able to provide these hulls at a cheaper rate, so basically initial prices may look more like $200 for a kit.
The marathon hulls are also getting closer, as is the decal kits.
Please let me know what everyone thinks.

[mickieb49]

hi guys,
Just a quick update, just started putting together the first hull with the new bottom ( see pic) also got the hull working much better now, set the COG at 260mm from the transom, and if you do the maths, that is 40%, the reason being is that this unit is slightly too much for the small hull.
Also look at the internal setup , instead of cutting the shaft shorter on the unit, iam going to keep it at 150mm so I only have to put the battery infront of the motor to get the right COG.
Take care20140316_132454.jpginside .jpgnew bottom.jpg

[flraptor07]

Mick, I don't know about anybody else but I would rather pay the extra $ for a Fiberglass hull over ABS any day. Fiberglass is much easier to repair and much stronger, in my opinion I wouldn't bother making a ABS hull. I'd like to hear what any body else thinks about this. When I'm looking at a hull and I see it's ABS I quit looking, I won't even consider buying a ABS hull.

[mickieb49]

Mick, I don't know about anybody else but I would rather pay the extra $ for a Fiberglass hull over ABS any day. Fiberglass is much easier to repair and much stronger, in my opinion I wouldn't bother making a ABS hull. I'd like to hear what any body else thinks about this. When I'm looking at a hull and I see it's ABS I quit looking, I won't even consider buying a ABS hull.

I have no intention on not producing the fiberglass hulls, will definitely still have these, was going to do the ABS ones so those guys who like rock bouncing can also have these hulls.
I will be making a second mold of the new hull shape so I can make 2 at a time, it takes the same time to make 2 as it takes to make 1.

Mike, your hull looks great mate, keep up the great work. Just remember to get the COG at around the 40% mark, or around 260mm from the transom, if you have it further back you may get the bouncing you see in my videos. I am in the process of changing the instructions to reflect this change. But please keep you build updates coming, it is good everyone else can see one being put together by some one else.
I have been advised that the Marathon plans are nearing completion ( had to change a few things) so hoping to be getting these up and going soon. So sorry it has taken so long, unfortunately working full time aswell as looking after 2 kids under 3 yrs takes toll on the shed time.
Got my laser cutter on Friday so I am trying to learn how to use that too.
Take care guys
Mick

[mickieb49]

Hi Mick,

No Problem mate I also have Family issue's, travel for work and whatever comes up. I am happy with the hull bottom but need to rework the sides and I am starting on the deck. Have not cut down the impeller shaft so I am good there LOL. I have a couple of question that you might have told me.....brain fade.
The flow straightener vanes when mounted have to be between the vanes in the rear cone correct?
The wear ring does it matter where the little vanes are placed?
About how much of a diameter / radius is needed on the rear of the inlet to hull?

Thank you,

Mike

Hi Mike,
the flow straightener vanes need to be lined up with the vanes in the rear cone.
The vanes in the wear ring does not mater what orientation they are.
On the rear edge of the inlet you need to only bevel it backwards at approx. 45 degrees, this is to release some of the pressure built up in the inlet.
Regards Mick

[timjz]

Hi Tim,
The problem with flat bottoms is the side slippage causing turbulence into the unit on turns, will work just not optimum.

I get that it won't be the best setup, but I've wanted to build both a little jet boat & a SK Daddle for a really long time.
I was really happy to see this pump come out, it looks pretty scale + it has an actual impeller, not a cut down prop!

So...will I need a skeg?

[mickieb49]

tIM
Its not that It wont work, it should work quite well, just not the optimum. Maybe ad some Loader gates? I am not entirely familiar with these , maybe someone else may chime in here?
regards Mick

[mickieb49]

Hi Guys, well the new hull is a success:

http://youtu.be/EuKOXa8jK_0

4 hulls are on their way to Steve at Off shore electrics.
Regards Mick

[Darin Jordan]

I received 2 of these drives from OSE.COM. Look vert nice. I'll be doing a conversion thread shortly using a Pro Boat FasTEC hull. Looks to be perfectly sized.