ORIGINAL: sundogz

I got more done on the JetCat. Tested it for leaks, were none. The Shoe Goo worked well. On the water cooling, I decided to keep the redundancy and ran two cooling systems. I drilled 2 more holes in the top for discharge (like a jet ski) so I can easily see if each side is cooling. And I patched the original hole in the side. I made a stainless bracket to hold the both esc’s on their sides. This made everything quite tidy, and all cooling lines are short and covered. The bracket is velcro’d to the tunnel, and the esc’s velcro’d to it, so that everything is removable if needed. The motor mount screw holes in the jet needed to be widened and I used a dremel tool to carefully do that. What a P.I.T.A, I should have done that before I installed the jets into the hull! (“note to self…). I drilled a hole in the transom so that I could to easily install/remove the motors using a long hex screwdriver. I used the steering boot hole to do that on the other side. I’ll just cover the hole with hull tape . Drilled another hole! and installed the antenna base with an o-ring seal. The receiver is velcro’d to the transom over the tunnel. The couplers from SicRc made it easy to connect the motors to the drives and everything is smooth and balanced. Now I need to program the esc’s and bench test everything. I will disable one of the esc’s bec by pulling a red wire on the ‘Y’ cable. Don’t want to burn up a bec (thanks, Steve). There’s a lot of room in the sponsons for moving the lipos to adjust the COG – your guess is as good as mine where that will end up being. I plan to use two Turnigy 2200mah 25C lipos unless run time is too short.

ORIGINAL: sundogz


Have you had any reservations about the P16 being a stepped hull? This is just speculation, but are you concerned that the froth caused by the stepped hull might induce aeration at high speeds? It's for this reason that I looked so long for a non-stepped hull to use for a jet conversion.

ORIGINAL: grael

Look like you've been putting a bit of spare $ into the project!

These sort of things (modern 3D printers) are pushing a world revolution in fast conception to manufacture.

For lower quantity production you might want to consider 3D printing PLA moulds to produce silicon rubber moulds with, then use those for polyurethane resin plastic final pieces. Got to include risers and sprues for resin inflow and air outflow, if you vacuum the mixed resin before pouring you can get some very nice parts out.

I'm experimenting with various design tools at the moment. Having some programming experience, I'm really liking the look of "openscad".


Working on a minimal budget at the moment, also doing a first revision redesign of my circuitboard, I'm looking to put more axis on board for multi product extruding, if you youtube "rostock and richrap" you'll see what I mean, multicolour prints.

Good luck with the jet unit production... I'm not so sure there's a big enough market for them but this thread and others on the forum have shown that RC jet boats are certainly being adopted by a lot more people. I still remember a local shop owner arguing with me that small Jet boats were not possible, that if it could be done somone would have already done it... Just the sort of person I enjoy proving wrong, wrong wrong!

ORIGINAL: sundogz

Mickie, I like the concept of a short bodied jet drive. You probably should soften the intake ramp transition. Eliminate the hard angle entirely and make it a smooth transition into the intake chamber. See arrow.

Grael, no, I haven't forgotten that project! But as I remember it, the whole hull bottom was a series of steps. And no 'unstepped' control hull to compare it to. I am still unconvinced there isn't some tradeoff or losses involved. But then, I have a hard head at times! Good to see you're still lurking.