New Hydromite Build

[stablgr]

Ok I'm still confused. Seems like some people like the flex cable drive and some the solid wire drive. I can see the advantage of using a solid wire drive in a configuration where the motor, propshaft and prop are all in-line. It also would appear to be the stronger set up. But wont there be a load of friction (heat and wear) with a solid drive in this hull design, given that all the drive components are not in a nice straight line?

If the flex drive is the way to go then that big fat string on my son's Strat is looking good!!!

[n.h.schmidt]

Wire drives

Hi
Wire drive can work well and even better that flex cable . Its at its best in uses where there is only a modest bend to the wire. A mono hull boat comes to mind. Usually the motor need only to point down at a gentle angle to be about right with the prop shaft outlet in the bottom of the hull. Even then , you can't have the motor placed far to the rear or the bend in the wire will be too great. The bend needed in hydros, riggers and cat hulls are usually steeper and wire may not always be the best way to go. With flex cable you have more options in the setup. Wire drive when correctly setup will have lower friction overall. A long drive line (the motor more to the front) favors the wire drive best. A short drive line (motor more to the rear) is best with flex cable. This is way I see it.
n.h.schmidt

[stablgr]

Ok. It looks like the .098 flex is the way to go.

On another issue. I was looking into what type of cells to use, and was originally going to stick with the seven Sanyo CP-1300-SCRs as suggested on the plan, however I recon I could squeeze a couple of 2S 20C 1800mAhr or 1500mAhr LiPo's in there in parallel and should give me a nice long run time. Even with the two 1800s the cell weight seems to be lower than the Sanyo's.

I realise that the voltage will be lower, but will I be able to select a suitable prop to give me reasonable performance with the 3000KV motor and the LiPo cells?

At the end of the day I'm not looking for the fastest boat in town, but to learn as much as I can with my first build. I can always go faster later.

Thanks for all your help so far.

[Avanti]

use one 3s 1500 pack she will fly
be careful on long runs as you will overheat the electronics

[stablgr]

So you think that with the paralleled 1800 mAhr LiPo's there's a chance of overheating the motor and ESC if run for extended periods?

From what I've worked out the LiPo's themselves should be ok with the motor I'm looking at. But I could be wrong!!

What's the most efficient way of cooling an out runner motor?

[Avanti]

minicatracing sells an outrunner cooler
my hydromite had no cooling it was fine for normal length runs
but extended runs would get it cooking

[stablgr]

I really didn't think it was going to take this long to build, but it's finally coming together.

Here's where I've got to so far.
Gary's Hydromite.jpg

Now if I could only stop sticking my fingers to the damn thing while waiting for the CA to dry

[stablgr]

And here's some of the hardware...

Hardware 1.jpg

[stablgr]

It looks like I'm going to have a few (ok, a lot) of imperfections to fill in. What is the best type of filler to use?

[Dr. Jet]

My experience with that motor/ESC comnbo is that you can runit forever on 2S with a Graupner 29 mm prop, and it will never get hotter than 130~135 degrees. No cooling is necessary, as long as you don't go crazy with the prop.

[Avanti]

The hull looks great stablgr

doc, I ran that motor & esc combo on 3s 1500 long run times and you could cook an egg on it (there seemed to be no ill effects after 9-14 runs (I realize prolonged use would kill it but for 24 buck does it matter, the speed is awesome on 3s. I would try 4s if I had one).

however 2s sounds like a great safe setup for longevity

edit: oh stablgr I used automotive glazing putty on my hydromite but any type of bondo should work fine

[ace028]

Looks great man, I can't wait to finish mine, I have the same hardware.

[Avanti]

where did you guys source the hardware and what was the cost?

[ace028]

I got mine from R2hobbies.com I can't remember the exact price, but was like under $10 for the strut, and under $20 for the rudder. Its the same exact parts as minicat racing, but without the price. I think R2hobbies distrubutes the brand. Minicat don't really make them, they get them from china or something and call it theirs.

[Doug Smock]

I really didn't think it was going to take this long to build, but it's finally coming together.

Here's where I've got to so far.
[ATTACH]8118[/ATTACH]

Now if I could only stop sticking my fingers to the damn thing while waiting for the CA to dry

Nice work.

Doug