cog for a micro hydro?

[bustitup]

I have one like the ones from minicatracing

[Simon.O.]

The Cg, Cog for most hydros begins at 10% of the afterplane. That is the distance between the rear of the sponson ride surface and the prop.
If this distance is 10" then your cg goes at 1" aft of the sponson rear and tune from there.

[HOTWATER]

I have one like the ones from minicatracing

bustitup, I just bought one of these and the Instructions say 15.5 cm from the transom (rear of the boat) on up, or about 6.1 inches. Should end up right where the front of the motor (shaft) and flex coupler meet.

-Kent

[bustitup]

thanks guys

[HOTWATER]

You got it man...

[bustitup]

well as it works theres not much room to move a battery around to adjust cog...so with simons method I took a measurment from the back of the sponson to where the drivedog meets the prop and it was 10" so using 10% of that which is 1"...when I push the 3s 2350mah lipo full forward my cog is 1" of the sponson...how lucky was that....this thing should rip with the rhino 3s 2350mah 25c...man its tight in this little hull....its got a 2445 3600kv feigao and a 32mm prop

now I have to figure how to squeeze some flotation in there somewhere

[bigwaveohs]

well as it works theres not much room to move a battery around to adjust cog...so with simons method I took a measurment from the back of the sponson to where the drivedog meets the prop and it was 10" so using 10% of that which is 1"...when I push the 3s 2350mah lipo full forward my cog is 1" of the sponson...how lucky was that....this thing should rip with the rhino 3s 2350mah 25c...man its tight in this little hull....its got a 2445 3600kv feigao and a 32mm prop

now I have to figure how to squeeze some flotation in there somewhere
I have two of these and the recommended distance in the instructions works perfectly...

[Meniscus]

You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

As you're adding flotation, don't forget the hatch! :tongue_smilie:

What does your battery weigh in grams?

[bigwaveohs]

I have two of these and the recommended distance in the instructions works perfectly...
There's plenty of room in the sponsons for flotation if you shape it to fit. I tried the 32mm prop but it didn't do much, probably because I'm only running 20C packs.

[bigwaveohs]

You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

As you're adding flotation, don't forget the hatch! :tongue_smilie:

What does your battery weigh in grams?

Do you have a source for a "lifting" prop?:cool:

[bustitup]

You may also be able to use a prop that has a little more lift, not too much though as it is easy to have too much lift at higher RPMs.

Mine runs great with the recommended balance and the stock prop. How does she run on the water, or have you tried yet? I started mine really wet and started to move back. Note: be careful of the climbouts as you move back, she can easily flip on you and quick. However, it may be that my CF version is more susceptible to this, but I haven't run one of the fiberglass ones to confirm.

As you're adding flotation, don't forget the hatch! :tongue_smilie:

What does your battery weigh in grams?

oh yes got to float the hatch...no I havnt run it yet

198grams

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7468&Product_Name=Rhino_2350mAh_3S1P_25C_Lipoly_Pack

[bustitup]

There's plenty of room in the sponsons for flotation if you shape it to fit. I tried the 32mm prop but it didn't do much, probably because I'm only running 20C packs.


I would like to see the inside of your boat

ben you too