Balance point on monos?

[Glenn Gates]

I,m new to monos and would like to know where the boats should balance at.

1. Speedmaster mono 38"- CMB Rs45

2. AC Lazer-40"- 67 Mac

3. Seaducer 40"- .67 CMB

4. Cal Craft 39"- 45 Mac

I have not run # 3 or 4 but the first two spent more time upside down than right side up this summer. Seem to just flip or dunk at the end of the straights .

Any replies appreciated.

Thanks,

Glenn

 

[P THOMAS]

I,m new to monos and would like to know where the boats should balance at.

1. Speedmaster mono 38"- CMB Rs45

2. AC Lazer-40"- 67 Mac

3. Seaducer 40"- .67 CMB

4. Cal Craft 40"- 45 Mac

I have not run # 3 or 4 but the first two spent more time upside down than right side up this summer. Seem to just flip or dunk at the end of the straights .

Any replies appreciated.

Thanks,

Glenn

Check balance point, 30-32% of lenght is usually good.

 

[Blackout]

My instructions for my Speedmaster .45 say the CG should be 11" in front of the transom.

Did you try raising the strut? That will help settle the hull into the water more.

 

[TimothyJones]

You might get different figures from the actual boat designers, but I have this easy formula John Finch Style. B= overall length, so 28% of B measured from the Transom .

Tim

 

[David vanmaris]

What tim said 28-30 is the general.

AMPBA#370

 

[Michael Costanzo]

hi glen, also depends on motor in the boat. have spoken to some really good mono guys and they had said that if the boat was orig set up for a 80 and now it is a 90/101, the cg could go as hi as 35% to keep the boat on the water. good luck. mike.

 

[David vanmaris]

Hey Glenn #3 #4 must be going too quick mate.

AMPBA#370

 

[Joe Warren]

I,m new to monos and would like to know where the boats should balance at.

1. Speedmaster mono 38"- CMB Rs45

2. AC Lazer-40"- 67 Mac

3. Seaducer 40"- .67 CMB

4. Cal Craft 40"- 45 Mac

I have not run # 3 or 4 but the first two spent more time upside down than right side up this summer. Seem to just flip or dunk at the end of the straights .

Any replies appreciated.

Thanks,

Glenn

The CG is going to be Approx in line with the Front of the Flywheel (everytime if checked)? So Engine location is very critical. Next it would be Best to find the Orginal building plans to see if the Boat has the Correct prop & strut adjustment? Most mfgers have a Basic prop & strut adjustment in the building specs. You can tweak from there. hope this helps you out?

 

[Glenn Gates]

hi glen, also depends on motor in the boat. have spoken to some really good mono guys and they had said that if the boat was orig set up for a 80 and now it is a 90/101, the cg could go as hi as 35% to keep the boat on the water. good luck. mike.

Thanks Mike, I do have some strong motors- some were set up by Steve Wood and the Rs 45 in the Speedmaster hull Was set up by Paul Stirton racing in AU.. I've always paid attention to the balance points on my hydros-just neglected to check on the monos.

Glenn

 

[dwilfong]

Glen I chased the balance on my 39" Cal Craft for the first half of the season. If the eng has lots of power you have to do thing different than most to keep the boat in the water. Move the eng forward to get 33% CG. Run a large fuel tank (16oz in mine). This way the fuel load is spreed out over a larger area. When you spreed out the fuel weight it makes the boat more stable. With a small tank all the weight is in the middle and up higher in the hull. You can adjust the fuel load to the water conditions and number of boats in the race. Slam the strut all the way down and give it as much neg as you can. This way you only run on the tips of the prop. The neg will also try to lift the bow of the boat but the CG more forward will make it run flat. This will also make the prop slip at crawl speed and give a great hole shot at the start .

Gust ask any one who has raced against my boat it is a ROCKET.

David

 

[BigChuck]

All of the information given is correct. HOWEVER you MUST know were the tank placement is in relation to the motor. If the tank placement is off and you go to run the boat it will plow/push the fornt until; the fuel burns off regardless of motor power.

 

[Ted buckley]

All of the information given is correct. HOWEVER you MUST know were the tank placement is in relation to the motor. If the tank placement is off and you go to run the boat it will plow/push the fornt until; the fuel burns off regardless of motor power.

Good point, Also I think finding the CG with a full tank of fuel, then a near empty tank is beneficial too. My hull with a full tank of fuel is approx: 31%, then as the race goes on - goes down to 28-29%. I'm still in the 27%-32% range for Mono's.

 

[BigChuck]

DING DING DING!!! Ted is the Winner!!! in my opinion. 31% is were most of the mono are at. Now add everything up!!! Shaken not stirred!!! :lol: :lol: :lol:

 

[Ted buckley]

DING DING DING!!! Ted is the Winner!!! in my opinion. 31% is were most of the mono are at. Now add everything up!!! Shaken not stirred!!! :lol: :lol: :lol:

:lol: :lol:

 

[dwilfong]

You will never know unless you try different things than every one else has done.

Or you can do what every one else dose and get the same results.

David

 

[Ted buckley]

You will never know unless you try different things than every one else has done.

Or you can do what every one else dose and get the same results.

David

David, I like your Dog picture. Every time I see it - It reminds me that I have to go home to my crying wife - every day, since ours died last week & 7 thousand dollars later.

 

[dwilfong]

You will never know unless you try different things than every one else has done.

Or you can do what every one else dose and get the same results.

David

David, I like your Dog picture. Every time I see it - It reminds me that I have to go home to my crying wife - every day, since ours died last week & 7 thousand dollars later.

Ted I had a lab before this pain in the a&&. Her hips went bad. spent a year messing with her till I put her down. I know the feeling.

David

 

[Glenn Gates]

O.K. Guys, I checked the Speedmaster first- 11" or 29.5%(tanks empty-17Oz.) The A.C. Lazer 40" 12.5" or 31% with a empty 24 Oz. tank-maybe I should move the Rs 45 into one of the 39 or40" hulls :blink: .

Thanks for your replies,

Glenn

 

[Ted buckley]

O.K. Guys, I checked the Speedmaster first- 11" or 29.5%(tanks empty-17Oz.) The A.C. Lazer 40" 12.5" or 31% with a empty 24 Oz. tank-maybe I should move the Rs 45 into one of the 39 or40" hulls :blink: .

Thanks for your replies,

Glenn

Glenn, you weren't still waiting for a reply on this - were you? If you are: Speedmaster = 11.02" @ 29% / Lazer sounds correct , but for a 40" boat should put it at about 11.6" - However; you have a .67 motor in that one, so 12.5" put's it at the high side. I noticed that you have a pretty good sized tank for the .45. I ran a 16oz. in mine, and that's when the cg. was hard to control - making it do (Front Dig) in the corner, until I burned the fuel-off. Also, I'd have alot of fuel left over after the race. Try a 10oz. and see how that goes. Put the CG at 29% Dry tank or 31-32% when the take is full. This way when the fuel burns, the CG will move back - hopefully to within 29%.. If your hull is digging in the corners(Bow down/Stern up) your CG may be off or your strut may have too much neg. angle. Check your trim tabs too.. (Bow up or flipping over) is the reverse of this. Also, one more point to add is the Manufac. instructions are just a guide line for the hull for CG. Always do a manual check of this to find the true CG of your boat.. Do the 2 index finger test/find the balancing point - then measure forward from the transom to find the length. Take the overall length of the hull and X's that by the measurement that you just took. Don't forget to do the % sign. This should give you a true measurement of where your at. It should fall around(i.e. 11.02 Speedmaster boat).

Sorry, maybe you know all this already - just trying to help. Go with smaller tanks if you can.

 

[Glenn Gates]

O.K. Guys, I checked the Speedmaster first- 11" or 29.5%(tanks empty-17Oz.) The A.C. Lazer 40" 12.5" or 31% with a empty 24 Oz. tank-maybe I should move the Rs 45 into one of the 39 or40" hulls :blink: .

Thanks for your replies,

Glenn

Glenn, you weren't still waiting for a reply on this - were you? If you are: Speedmaster = 11.02" @ 29% / Lazer sounds correct , but for a 40" boat should put it at about 11.6" - However; you have a .67 motor in that one, so 12.5" put's it at the high side. I noticed that you have a pretty good sized tank for the .45. I ran a 16oz. in mine, and that's when the cg. was hard to control - making it do (Front Dig) in the corner, until I burned the fuel-off. Also, I'd have alot of fuel left over after the race. Try a 10oz. and see how that goes. Put the CG at 29% Dry tank or 31-32% when the take is full. This way when the fuel burns, the CG will move back - hopefully to within 29%.. If your hull is digging in the corners(Bow down/Stern up) your CG may be off or your strut may have too much neg. angle. Check your trim tabs too.. (Bow up or flipping over) is the reverse of this. Also, one more point to add is the Manufac. instructions are just a guide line for the hull for CG. Always do a manual check of this to find the true CG of your boat.. Do the 2 index finger test/find the balancing point - then measure forward from the transom to find the length. Take the overall length of the hull and X's that by the measurement that you just took. Don't forget to do the % sign. This should give you a true measurement of where your at. It should fall around(i.e. 11.02 Speedmaster boat).

Sorry, maybe you know all this already - just trying to help. Go with smaller tanks if you can.

Thanks Ted, Boats are not digging in corners- both are fast and perhaps too light. I'll play with the struts a little next year(neither have much movement but I can tilt them a little). Also going to try adding weight(inside the noodles) that I can adjust fore and aft. May also look into some different props- I ran a x646/3 on the 45 and a x457/3 on the 67(@4200 ft. elevation).

Thanks,

Glenn