where to find CG in a scale

[misshydro]

Wanted to findout where to find the best CG to place the engine on scale hydro.

 

[Duck899]

Thats a good question.....

I typically place the engine so the flywheel C/L is in line with the turn fin or back of the sponson. But, the further ahead you can get the engine under the cowl, the better. When I mounted the CMB in the Bardahl, I had to keep the engine concealed under the dummy engine. The dummy engine for the most part is centered on the rear sponson edges like the full size boat. I ended up with the dummy engine where it should be and the CMB right to the front of the dummy engine and did not have to cut out the front of the dummy Merlin. I had all the equipment when I was placing things and arranging and you should do a mock up when deciding so as to get everything close to final position and end up with the CG on the turn fin, approx. Remember to add 6 ounces mininum to the left sponson as well for torque.....

 

[misshydro]

Been reading some would place there engine at the back of the sponsons or the center of the turnfin.

 

[glenng]

Wanted to findout where to find the best CG to place the engine on scale hydro.

Nessa, I add every bit of hardware, parts,shaft, prop, servos, battery, tanks-everything except fuel to the boat and move the eng. and mounts back and forth till the cg is about 1/2"-1" behind sponson transoms. Then drill the mounting holes for the motor. Keep the back end as light as pos. New scale Oberto?

 

[glenng]

Thats a good question.....

I typically place the engine so the flywheel C/L is in line with the turn fin or back of the sponson. But, the further ahead you can get the engine under the cowl, the better. When I mounted the CMB in the Bardahl, I had to keep the engine concealed under the dummy engine. The dummy engine for the most part is centered on the rear sponson edges like the full size boat. I ended up with the dummy engine where it should be and the CMB right to the front of the dummy engine and did not have to cut out the front of the dummy Merlin. I had all the equipment when I was placing things and arranging and you should do a mock up when deciding so as to get everything close to final position and end up with the CG on the turn fin, approx. Remember to add 6 ounces mininum to the left sponson as well for torque.....

That's interesting- about adding weight to the left sponson-I run around 4200 ft. elevation and we add no weight to the sponsons. I have two boats(Pay& Pak and Eagle Electric) that lift the left sponson at the end of the straights. The fin will pull the boat down once you give it a little rudder. I'll be moving closer to sea level next year and will remember this Rob.

Thanks,

Glenn