Center of Gravity for 1/8th scale - turbine type hull

[Mike Rappold]

Before painting a new 1/8th scale, Bud type of hull, I am in the process of checking the center of gravity. Thus adding weight to the nose, etc.

How far behind the rear of the sponsons have people been targeting for the center of gravity?

What about the distance the leading edge of the turn fin from the rear of the sponson?

Thanks in advance.

Mike Rappold

 

[Wesleys Custom RC]

Before painting a new 1/8th scale, Bud type of hull, I am in the process of checking the center of gravity. Thus adding weight to the nose, etc.
How far behind the rear of the sponsons have people been targeting for the center of gravity?

What about the distance the leading edge of the turn fin from the rear of the sponson?

Thanks in advance.

Mike Rappold

The last boat I built I put the cg right on the collet and the turn fin is centered there also. That is with a full tank of fuel. It seems to like it there. The front canard likes to be nutural even in rough water.

 

[namba276]

Before painting a new 1/8th scale, Bud type of hull, I am in the process of checking the center of gravity. Thus adding weight to the nose, etc.
How far behind the rear of the sponsons have people been targeting for the center of gravity?

What about the distance the leading edge of the turn fin from the rear of the sponson?

Thanks in advance.

Mike Rappold

The last boat I built I put the cg right on the collet and the turn fin is centered there also. That is with a full tank of fuel. It seems to like it there. The front canard likes to be nutural even in rough water.

I' ve found that with any three point hydro , you are looking for the cg to be at the trailing edge of the sponsons. I have built many boats and as I build and adjust hulls over the years, balance is the main goal. with the boat together you should be able to hold the boat in running trim with your index fingers close to the sponson trailing edge. I have two 21 hulls of different generations. My older boat has 7 oz. of lead to keep it from " dancing" down the straight away. I moved the engine forward 1-1/2" and added no lead in my new hull to acheive the same result. Basically I have increased the forward thrust without using HP for lift. If the balance is too far back, you will need lots of lift which robs you of HP.

Bob

 

[Wesleys Custom RC]

Before painting a new 1/8th scale, Bud type of hull, I am in the process of checking the center of gravity. Thus adding weight to the nose, etc.
How far behind the rear of the sponsons have people been targeting for the center of gravity?

What about the distance the leading edge of the turn fin from the rear of the sponson?

Thanks in advance.

Mike Rappold

The last boat I built I put the cg right on the collet and the turn fin is centered there also. That is with a full tank of fuel. It seems to like it there. The front canard likes to be nutural even in rough water.

I' ve found that with any three point hydro , you are looking for the cg to be at the trailing edge of the sponsons. I have built many boats and as I build and adjust hulls over the years, balance is the main goal. with the boat together you should be able to hold the boat in running trim with your index fingers close to the sponson trailing edge. I have two 21 hulls of different generations. My older boat has 7 oz. of lead to keep it from " dancing" down the straight away. I moved the engine forward 1-1/2" and added no lead in my new hull to acheive the same result. Basically I have increased the forward thrust without using HP for lift. If the balance is too far back, you will need lots of lift which robs you of HP.

Bob

Ya! what he said! I learned in car racing that a well balanced car will whoop horse power any day............as well as a good driver. As confushea say "yo musta hava ballance."