New Products Flash Sale
Thread Tools
Old May 27, 2015, 12:24 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Discussion
DIY rc sailboat

Hello everyone;

I made an RC boat out of an isolation matter (dont know the name usually it is blue )
I used RC car. The rudder rotates about 45 degrees and when you stop pusing joystick it comes back to center (No servo only a spring). And Acceleration/Reverse controls are for Sheet (I used a system that only motor can rotate a gear not the sheets). I added two wings that lifts boat downwards therefore windward side at upwind. I dont think they work but they look cool . Whatever I tried it but she kept headig up. And no matter how much I rotated the rudder I could not bear away. Why do you think this happened I got the pictures. It did lean leeward side much but I've seen many RC boats lean way more. Anyway can you look at the pictures and tell me what seems wrong?
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Sign up now
to remove ads between posts
Old May 27, 2015, 12:30 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Also I am a good sailor the sail angles were fine I loosed the sheets it still kept heading up.
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 12:38 PM
JIM CALDWELLA is offline
Find More Posts by JIM CALDWELLA
Registered User
United States, OH, Cleveland
Joined Aug 2002
448 Posts
Jib too large? Pulling the bow to windward?
JIM CALDWELLA is offline Find More Posts by JIM CALDWELLA
Reply With Quote
Old May 27, 2015, 12:47 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
...
gtakaz is offline Find More Posts by gtakaz
Last edited by gtakaz; May 27, 2015 at 01:08 PM. Reason: dont even know how to delete :)
Reply With Quote
Old May 27, 2015, 01:00 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Quote:
Originally Posted by JIM CALDWELLA View Post
Jib too large? Pulling the bow to windward?
But shouldn't it do the opposite? Also normal sailboats (lifesize) has genoa's much much larger it would effect them wouldn't it? If I look smartass thats because my englsh is bad and I am not used to this forum thing
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 01:13 PM
boater_dave is online now
Find More Posts by boater_dave
Big Boats Rule!
boater_dave's Avatar
Wisconsin
Joined Jun 2007
2,204 Posts
It looks like you've got all the right stuff there, and the proportions look pretty good, too. It's hard to see the sails because they are clear. Any pics of her sailing?
The problem you are describing is called weather helm. When the breeze comes on, the boat turns into the wind. The cause is the balance point between the sail rig and the keel/rudder is off (too far astern).

Some things to try...
Rake mast forward (moves balance point forward)
Move entire rig forward
Move jib forward
Slack off mainsheet (let it luff a bit for testing)
Slack off boom vang to depower main (for testing)
Bring in jib sheet (is it luffing already?) But don't close the slot

A bit harder to try, but...
Move keel aft
Move rudder aft
Larger rudder
Smaller main sail

Don't get too discouraged. If you are not working from a proven design/plan you are going to have to work out a few bugs. And all of these suggestions should be done a little at a time and watch what happens on the water.
It would also be very helpful to take a picture of the boat straight down the mast with the boat laying sideways to see how the sails sit.
And one last thought. With your steering setup, is the rudder held in position by anything other than the spring when sailing straight? If not, is the spring strong enough? If not, a more balanced rudder may be needed. Maybe the boat is just pushing the rudder over.

Dave
boater_dave is online now Find More Posts by boater_dave
Reply With Quote
Old May 27, 2015, 01:28 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Quote:
Originally Posted by boater_dave View Post
It looks like you've got all the right stuff there, and the proportions look pretty good, too. It's hard to see the sails because they are clear. Any pics of her sailing?
The problem you are describing is called weather helm. When the breeze comes on, the boat turns into the wind. The cause is the balance point between the sail rig and the keel/rudder is off (too far astern).

Some things to try...
Rake mast forward (moves balance point forward)
Move entire rig forward
Move jib forward
Slack off mainsheet (let it luff a bit for testing)
Slack off boom vang to depower main (for testing)
Bring in jib sheet (is it luffing already?) But don't close the slot

A bit harder to try, but...
Move keel aft
Move rudder aft
Larger rudder
Smaller main sail

Don't get too discouraged. If you are not working from a proven design/plan you are going to have to work out a few bugs. And all of these suggestions should be done a little at a time and watch what happens on the water.
It would also be very helpful to take a picture of the boat straight down the mast with the boat laying sideways to see how the sails sit.
And one last thought. With your steering setup, is the rudder held in position by anything other than the spring when sailing straight? If not, is the spring strong enough? If not, a more balanced rudder may be needed. Maybe the boat is just pushing the rudder over.

Dave
Thanks a lot this is very helpful Well the sails are actually a plastic umbrella cut by hand so it is very amateur. Jib looks perfect in my opinion (because of the round shape of an umbrella but main sail is flat as hell even tough I tried my best with battens and stuff. I tried sailing with the main sail closed but it helped just a little.

Rudder spring looks ok. I did not take any pictures of her sailing because she bearly sailed. It was more like "I put her on the water wind blew I tried to turn leeward but she kept tacking".

I decided before to make a longer body and use a heavier load on keel because I thought problem was caused of the boat leaning too much and rudder did not work but then I've seen rc boats lean way more. So there is no mast to take picture of right now.

Also by "Make the rudder lager." you mean taller or wider? I dont think elecrtic motor can handle a wider rudder but taller can be fine. I decided the locations roughly just by looking. Thanks again for your comments
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 01:56 PM
Boomer1 is offline
Find More Posts by Boomer1
Boomer1
Boomer1's Avatar
United States, CA, Temecula
Joined Sep 2009
3,846 Posts
gtakaz
What are the dimensions of the boat? How much does it weigh? Pictures are dark making it a bit hard to see details. Suggest turning on some lights to get better photos! You have a giant brass looking turnbuckle on the backstay - may be adding unwanted weight to the stern?
The hull looks kind of like a "marble head" design.

Dave has provided lots of good suggestions. My first impression is the rudder may be to far forward. Not knowing the boats size and weight whatever we suggest or basically guesses.

Some good pictures would be helpful.
Boomer1 is offline Find More Posts by Boomer1
Last edited by Boomer1; May 27, 2015 at 02:09 PM.
Reply With Quote
Old May 27, 2015, 02:29 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Quote:
Originally Posted by Boomer1 View Post
gtakaz
What are the dimensions of the boat? How much does it weigh? Pictures are dark making it a bit hard to see details. Suggest turning on some lights to get better photos! You have a giant brass looking turnbuckle on the backstay - may be adding unwanted weight to the stern?
The hull looks kind of like a "marble head" design.

Dave has provided lots of good suggestions. My first impression is the rudder may be to far forward. Not knowing the boats size and weight whatever we suggest or basically guesses.

Some good pictures would be helpful.
Well the boat does not have a mast or sails anymore the second picture (white) is what it is right now and it is pretty bright I can't get better photos. I Cut and sanded the hull all just by looking. I just wanted to make it a long boat with a long mast and took reference from photos I've seen online.

The dimensions are;
97cm Mast

55cm Hull

26cm Keel

11cm Rudder

23.5cm boom

3 cm of the boat (middle to keel) is in water so water length is same as boat length.

Keel weight is 215gr
Boat is about 1 kg (Not sure cause I weighed with and without boat then subtracted )
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 03:45 PM
SirHarrisTweed is online now
Find More Posts by SirHarrisTweed
Registered User
Joined Sep 2014
12 Posts
Helm is a function of the center of effort (CE) of the sailplan in relation to the center of lateral resistance (CLR) of the hull. If the CE is forward of the CLR, lee helm; if the CE is aft of the CLR, weather helm. If you can't move the keel aft, maybe move the mast forward. Or reduce the size of the main?

Ideally, to sail fast you should use very little rudder anyhow. Maybe try adjusting the headsail to power up. If it's too tight when the main is drawing perfectly, it's impossible to tell by looking at it but it won't make much power and that'll move your center of effort aft, producing weather helm.
SirHarrisTweed is online now Find More Posts by SirHarrisTweed
Reply With Quote
Old May 27, 2015, 04:14 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Quote:
Originally Posted by SirHarrisTweed View Post
Helm is a function of the center of effort (CE) of the sailplan in relation to the center of lateral resistance (CLR) of the hull. If the CE is forward of the CLR, lee helm; if the CE is aft of the CLR, weather helm. If you can't move the keel aft, maybe move the mast forward. Or reduce the size of the main?

Ideally, to sail fast you should use very little rudder anyhow. Maybe try adjusting the headsail to power up. If it's too tight when the main is drawing perfectly, it's impossible to tell by looking at it but it won't make much power and that'll move your center of effort aft, producing weather helm.
I am rebuilding the hull and sails. But as I said they are made of umbrella I cant trim them.

I can move the keel aft but mast and keel location look good to me, I mean placing the keel closer to aft will look ridiculous there must be some other reason behind the problem.

Maybe I can move mast 0.5 cm forward, the rudder 2 cm aft and decrease the mainsail area but would it make that much difference? As I said before I sailed without mainsail and still weather helm.

Also maybe the keel weight is too light and the boat did not have the chance to speed therefore I could not control it by rudder? This was the first idea I had my other plan is to make the boat longer so it floats more that I can add weight to keel?

I found these photos my brother took maybe they will help
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 05:00 PM
Boomer1 is offline
Find More Posts by Boomer1
Boomer1
Boomer1's Avatar
United States, CA, Temecula
Joined Sep 2009
3,846 Posts
Your boat is similar in weight and length to a Micro Magic
A Micro Magic specifications are:
Overall length, approx. 535 mm 21.7"
Overall height approx. 980 mm = 38.5"
Sail area (cm2) 1450 cm²
Hull width 180 mm
All-up weight, approx. 910 g = 2.06lbs.

Your boat is 55 CM or about 21.6 inches (about the same as the MM)
Your boat weights 1kg or 2.2lbs. again very similar to the MM.

Don't know the beam (width) of your boat, but looking at it, I'd say the MM has a wider beam. Narrow boats are generally very "tender" meaning they are prone to healing over in very little wind. The wider beam on the MM provided added stability. Your keel fin is long compared to the MM keel. Wondering if a shorter keel fin might help?

I suspect the keel ballast may need to be heavier. I posted a picture of boat made back in the mid 90s called Innovator . It's hull is similar to yours in appearance the Innovator is larger at 914 mm (36") it looks to have similar proportions to your boat. From all reports, it has some of the same issues you are dealing with. Notice how long the keel fin is on the Innovator.

You are going to do a lot "trial and error" to determine exactly what is needed to correct the handling issues. There may be a point that you determine, the design just doesn't work

That can happen. I really don't have definitive answer for you.
Boomer1 is offline Find More Posts by Boomer1
Last edited by Boomer1; May 27, 2015 at 05:25 PM.
Reply With Quote
Old May 27, 2015, 05:14 PM
gtakaz is offline
Find More Posts by gtakaz
Registered User
Joined May 2015
9 Posts
Quote:
Originally Posted by Boomer1 View Post
Your boat is similar in weight and length to a Micro Magic
A Micro Magic specifications are:
Overall length, approx. 535 mm 21.7"
Overall height approx. 980 mm = 38.5"
Sail area (cm2) 1450 cm²
Hull width 180 mm
All-up weight, approx. 910 g = 2.06lbs.

Your boat is 55 CM or about 21.6 inches (about the same as the MM)
Your boat weights 1kg or 2.2lbs. again very similar to the MM.

Don't know the beam (width) of your boat, but looking at it, I'd say the MM has a wider beam. Narrow boats are generally very "tender" meaning they are prone to healing over in very little wind. The wider beam on the MM provided added stability. Your keel fin is long compared to the MM keel. Wondering if a shorter keel fin might help?

I suspect the keel ballast may need to be heavier. I posted a picture of boat made back in the mid 90s called Innovator . It's hull is similar to yours in appearance the Innovator is larger at 914 mm (36") it looks to have similar proportions to your boat. From all reports, it has some of the same issues you are dealing with. Notice hold long the keel fin is on the Innovator.

You are going to do a lot "trial and error" to determine exactly what is needed to correct the handling issues. There may be a point that you determine, the design just doesn't work

That can happen. I really don't have definitive answer for you.
Thanks a lot these answers really helped me. Ignorance is not bliss I guess
gtakaz is offline Find More Posts by gtakaz
Reply With Quote
Old May 27, 2015, 06:14 PM
Rusty Nail is offline
Find More Posts by Rusty Nail
Rusty
Rusty Nail's Avatar
Auckland, New Zealand
Joined Feb 2006
972 Posts
You might have more luck with a balanced Unarig. Very quick and simple to make and effective, with no stays to worry about so can be stepped easily in many positions. Being balanced needs a lower torque servo to move.
Some polystyrenes are not closed cell so are not particularly waterproof and will take on water.
One kilo with a 250gm bulb is not optimum. Bulb should be a least half of the total weight with a medium length keel. This means building light.
For a blow by blow tutorial on building a quick cheap yacht that sails well - see my thread:
Rusty Nail is offline Find More Posts by Rusty Nail
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Joysway Caribbean RTR RC Sailboat and Westward 18 RC sailboat manninge Sailboats 3 Apr 09, 2015 05:49 PM
New Product DIY RC Car OH35P01 1/35 KIT + 9115 1:12 2.4GHz 2WD Brushed RC Truck samiluo Car Talk 3 Feb 06, 2015 12:57 AM
Found SANTA BARBARA RC sailboat wyldrydes2 Boats (FS/W) 1 Jan 31, 2015 11:09 AM
Sold Wind II Classic Marblehead 50/800 RC Sailboat nikram58 Boats (FS/W) 2 Jan 06, 2015 11:07 PM
Sold Cheerio II Vintage Marblehead 50/800 RC Sailboat nikram58 Boats (FS/W) 3 Jan 05, 2015 04:12 PM