Center of Gravity

Intlwaters

Help Support Intlwaters:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
right on, its good to hear what has worked for others. I know every hull and motor combo will be different in respect to thier CG. But its always good to have a starting point. Putting up a post like this will sometimes give a different prospective, often leads to a better idea, or just flat out another way to go. I thank everyone that has put in thier 2 cents.
 
I have the prather set at 29% and I like how it cuts through the chop and rides flat but I think 28% to 27% would lossen her up on a good water day and compete.
 
A well set up mono for heat racing looks like a dog in calm water.
So true. I have a hard time running my heat racing monos in non-race water conditions as I have to fight the urge to make adjustments to free it up. Then there is the other RC boaters commenting on how slow your mono looks when its out there by itself.

BTW. I have your Mono Mania article from the '97 Roostertail article saved. Good stuff. Thanks for your contributions to the hobby.
 
Yes it is funny how a boat will be smoking fast by its self on the water and never finish a race.

Most boats will fall in the 30% to 33% range to race. Good rule of thumb is the starter belt is at the balance point.

Some led under the eng works every time.

Remember how it flies when out of the water means as much as how it rides in the water.

When you start getting over 70MPH in race water it is a whole different world.

Where the prop is in the water means allot. set the boat on the table and set the prop so the %70 mark is even with the table. You can run a bigger Dia prop if only on the tips.

Also will cure the lean in the boat.

David
 
Last edited by a moderator:
Dave Dave Dave <_< Wanna make fun of my shorts too ? :p

That boats got a new driver now BTW - your gonna have to beat HER to post that again. LMAO

Johns quote that Sean referenced is sooo true, and that hard to do sometimes if your testing alone.

Andy
 
Last edited by a moderator:
Yes it is funny how a boat will be smoking fast by its self on the water and never finish a race.

Most boats will fall in the 30% to 33% range to race. Good rule of thumb is the starter belt is at the balance point.

Some led under the eng works every time.

Remember how it flies when out of the water means as much as how it rides in the water.

When you start getting over 70MPH in race water it is a whole different world.

Where the prop is in the water means allot. set the boat on the table and set the prop so the %70 mark is even with the table. You can run a bigger Dia prop if only on the tips.

Also will cure the lean in the boat.

David
David can you clarify the "70%mark" im lost with that.
 
Last edited:
Yes it is funny how a boat will be smoking fast by its self on the water and never finish a race.

Most boats will fall in the 30% to 33% range to race. Good rule of thumb is the starter belt is at the balance point.

Some led under the eng works every time.

Remember how it flies when out of the water means as much as how it rides in the water.

When you start getting over 70MPH in race water it is a whole different world.

Where the prop is in the water means allot. set the boat on the table and set the prop so the %70 mark is even with the table. You can run a bigger Dia prop if only on the tips.

Also will cure the lean in the boat.

David
David can you clarify the "70%mark" im lost with that.
I think what David is referring to is 70% out from center of the prop.
 
Last edited by a moderator:
Yes it is funny how a boat will be smoking fast by its self on the water and never finish a race.

Most boats will fall in the 30% to 33% range to race. Good rule of thumb is the starter belt is at the balance point.

Some led under the eng works every time.

Remember how it flies when out of the water means as much as how it rides in the water.

When you start getting over 70MPH in race water it is a whole different world.

Where the prop is in the water means allot. set the boat on the table and set the prop so the %70 mark is even with the table. You can run a bigger Dia prop if only on the tips.

Also will cure the lean in the boat.

David
David can you clarify the "70%mark" im lost with that.
I think what David is referring to is 70% out from center of the prop.
Yes that is the reference.
 
Another tip not mentioned in the articles..................When the boat is riding at full speed and touching the water..............look at the transom as a hinge. or better yet, the pivot point of a teeter toter. When the bow comes up all the hardware on the transom goes down. That that is in motion tends to stay in motion. If your tuned pipe is hanging way past the transom it will leverage the bow into rising higher when the bow starts upward motion. Picture the bow as one person on a teeter toter and the pipe extended past the transom as the other person on the teeter toter.. They help each other stay in motion!!!!! Which is bad!!!!!!!! Some of our mono hulls get so out of shape while racing because of issues like the pipe extending too far past the transom. I recently had a gas mono that got really stupid after 3 laps. When the bow came up the boat got really crazy. The pipe was a steel pipe and it extended way past the transom. I put a shorter aluminum pipe on the boat and the problem went away. Sometimes going overboard on heavy pipes etc. gives you a better perspective on how things affect the ride of the boat. The 30 % cg is an aerodynamic cg. Balancing the aerodynamic cg and the weight it takes to keep the bow in place is sometimes a challenge. Trim tabs are usually the solution.
 
Funny thing is some directions tell you where to place the motor.Built like the plans shows the hull is to wild.I run alot of the microbursts and had to move the motor as far forward as i could and still ended up using weights on the bow.The good thing is it keeps the pipe inside the hull not sticking past the transom.My gas microburst the steel pipe is like John said its too long might have to get something else for it.Great reading.
 
We setup 2 NIB gas Vee hulls & one rebuild over the weekend the wind & chop were race course waves. We had one blow-over mine. The water was just rough enough for race water setup .the dark spot on the vid is when I droped my camcorder in the drink ,last season a strong wind blowing from right to left.

 
Back
Top