Kermit, the Hydro VX electric

[puttekula]

Let me introduce Kermit. A Gas hydro converted to electric. I have one question to start with. Before
I start planning the motor and battery position. Plz look at the pic. Where should the COG be for this kind of boat?
Position A, B or C? Or somewhere between? Hull length appr 40"

Its this model of boat.

Thx in advance

[h2o 1]

More in the C area. Im not familiar with that hull, but hydro's cog is usually just behind the sponsons.

[FRED]

need a clear picture, too dark.

[puttekula]

[h2o 1]

From the side view,in the B area.First pic,i couldn't see the sponson bottoms.

[Fluid]

A lot depends on the model's use - sport, oval racing, or SAW racing. Since this is effectively a rigger and not a typical hydro, start with 60% of the total weight on the front sponsons, 40% on the prop. Riggers do not run as much weight on the sponsons as a sport or scale hydro does.




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[puttekula]

Main goal is sport-saw. Quite clear huh...? My goal is to reach 75mph and to get a boat fun to drive.
My hardware is :
Castle 2028/780
Hyperion 5000/45c/5s x 2 for 10s
Turnigy 240A/12s
Octura 1657 (for starter)

When I measure the hull incl stinger/prop the theoretical cog stays with Fluids tip at just between B and C.

Could that be a good starting point?

[Fluid]

As long as you have the ability to shift the CG at least 2cm for and aft that should work to start. You can use a bigger prop too, I'd not go less than 60mm, a 'classic' 10S prop for motors like the 2028 is the x462. I'd go with the x462 to start, then eventually move up to an x665 or ABC 2316 or 2414 is the boat handles it. Your packs are the weak point, the 2028 has plenty of torque for 10S for a rigger. Expect well over 120 km/h with this latter setup once properly set up.


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[RaceMechaniX]

I would aim for the CG to be right at the rear of the sponson surface to 2" behind the sponson surface. This is the general rule for sport hydro's, however electric riggers tend to benefit from slightly heavier tail weight to keep the prop hooked up. Adjustability will be the key here.

TG

[iamandrew]

Where did ya get the hull from? thought Mr park didnt have any of these because RCMK never made the hulls

[puttekula]

Thx guys. Now I have something to start with.

I dont know of Mr Park but the hull comes from my "local LHS". (In Stockholm 180 km from here)

[puttekula]

So, after som COG testing there are a couple of alternatives. In both alternatives the COG seems to be good if 2 packs of my Hyperions
is stuffed all the way up front in the nose of my "frog".
Alt. 1 is the motor quite near the front packs. That makes 2x5000 5s packs in series. Quite light boat but maybe not that much punch
for this motor? The axle goes out in the original position.
Alt2 is the motor more to the back and another 2x5000 5s packs between the motor and the front packs. That makes a 2p combo. Quite heavy
boat but more juice to squize out of the packs. The axle goes out further back from the original position. But plenty of space anyway due to a long hull.

What do u guys think is the best alternative?

[puttekula]

Motor bracket constructed. Now for the metal workshop....

[carlcisneros]

very nice rendering of the motor mount

[puttekula]

Yep, if it was that easy to get them in real....