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turbo subaru dyno jet with cored hull

Posted: Wed Nov 16, 2016 8:44 am
by electric tug
Hi, I am starting a dyno jet build.
two things that are going to de different with this build:

1. Im using a 1/2" core rather than Aluminum or wood. wood is far too weak for river travel.
also weight is a consideration. A carbon fiber/kevlar hull, costed out is less money than buying a new welder, learning to weld, buying the special feed gun, the wire, the electricity, and the Aluminum which after cutting about 1/4 of all the AL is scrap.

The Carbon fiber and kevlar gives amazing abrasion and impact resistance. I know. I have been experimenting with this for years.
the honeycomb, simply bends/deflects to the Impact(rock), it is not rigid, and allows for deflection. Its not perfect, of course, but Aluminum will hole too, no material is perfect. I have seen demos where Aluminum will fail, before a cored hull will.

Finally, the weight saved. I am guessing the hull in core will be about 1/3rd less than a wooden hull, and certainly far less then an Al hull. This gives me more allowable weight for a bigger engine.

2. I wont be using a standard jet ski. This boat is essentially a jet sprint. new Zealand Sprints usually have v 8's in them and the standard sprint is 13 ft long. by 5 ft wide.

My engine of choice comes from a subaru, are cheap , readily available and will likely mate to a standard stx jet pump or maybe even (im hoping) with a Berkeley or dominator jet drive. The EJ20 DOHC Single Turbo Power output ranges from 197 bhp (147 kW; 200 PS) @ 6000 rpm and 260 Nm for the GT to 220 PS (162 kW; 217 bhp)

I am concerned about room for the engine, but it will e easy to just extend the transom area by a foot or so IF necessary.

The core is 1/2 inch Nida core. using 1 layer of woven cloth each side, 1 layer CF, 1 layer kevlar 1 layer cf.
I will have to do some alterations. But in general, This should be a very peppy boat with easy to find parts.

wish me luck. core ordered yesterday...

the first challenge

Posted: Thu Nov 17, 2016 10:28 am
by electric tug
HI, If any one out there is reading this, I came across the first hurdle today. (Of Many Im sure).

I now own 7 sheets of 1/2inch Nida core.
arrived today.

But there is a slight issue;

Nida core, in all thier wisdom (or greed?), does not make 4 x 8 sheets of core. Nope!, they had to break from tradition and make
4 ft x 7 ft sheets...
so, how does that affect my build? its messes with my glen-l patterns, which are developed for 4 x 8 sheets of ply.

so thankfully there is a solution. First I have to cut a 4 x 7 sheet in half and epoxy it together to make one long 14 ft x 2 ft sheet.

then I can trace the patterns out onto that to cut it. It will get the same effect but the joint will not be at the same place as on the patterns. I dont see any huge issues tho.
Ill post some pics to explain it.

Re: turbo subaru dyno jet with cored hull

Posted: Thu Nov 17, 2016 7:34 pm
by electric tug

Re: turbo subaru dyno jet with cored hull

Posted: Sun Nov 27, 2016 12:37 pm
by gap998
Your video is showing as private on the link.

Re: turbo subaru dyno jet with cored hull

Posted: Sun Nov 27, 2016 1:45 pm
by garrech
Same here, can't view.