Outboard steering sweep?

[Kyle Adams]

I have an Ossi hull, Gizmo engine and a Lawless lower. What amount of steering angle, movement, sweep should I set up the hull with? I'm not sure the correct term. Thank you all for any help.

 

[jaxracer]

If I’m reading this correct, you’re asking how far should you allow your servo to move the engine to turn?

I think it comes down to personal driving preference. A good rule of thumb is if you can turn it so much that the boat spins out, then you have too much steering. These boats shouldn’t need a ton of steering, I would say somewhere in the 30 degree range is max what you want. Try it and then adjust if you need more or less.

 

[Kyle Adams]

I'll start from there. Thank you for the response.

 

[Grimracer]

With a tunnel boat I like to set it up.. if I turn aggressively I would turn inside buoy 3 by about 10 feet.

Grim

 

[Grimracer]

o yea.. throw is correct.. so is deflection AND SWEEP! you got this!

Grim

 

[john v]

max the servo travel , yes you will only need a couple of degrees for turning but when you come in to the dock after the race you will need all the travel because you are not on plane, 5 or more drivers are coming in at the same time

 

[Grimracer]

I am usually PARKED BEFORE THE REST FINISH THE HEAT... (i jest!)

grim the stinker!

 

[Mark Anderson]

And please don't adjust the throw with the end point. Use the correct length servo arm to get it right.

 

[Kris Flynn]

Hey Mark, what is your/the theory with that?
Cheers

 

[Mark Anderson]

It's not a theory. If you are using too long of a servo arm and cutting the throw down with end points. You are loosing servo torque and resolution. Simple leverage tells you that using too long of an arm looses mechanical advantage, thus torque. If you are only using 50% of the servos travel, your are loosing resolution. If it has 1024 steps, you want to use them. Modern radio equipment has made people lazy when designing linkage. Always optimize the linkage before resorting to electronics.

 

[Grimracer]

Here is where Mark and I might disagree..

Below is not an opinion.

You want as long a steering arm as you can put in the application. We have plenty of power and so thats not lacking. And the reason.. IT IS BEST.. to have the least hysteresis the system can provide. This, mechanically gets you as close as possible linear. Which provides you the best mechanical feel, feedback and influence.
Your radio system is FULLY capable of adjusting the endpoints so take advantage of that.

In the end there is no wrong way. So give a few things a go and have fun doing it.

Grim

 

[Andy Greene]

One thing I always liked to do once the end points are too your liking, is slow the rate -
It doesnt have to turn super quick left or right. Just my .02

 

[Kyle Adams]

It's interesting to read the spectrum of thoughts. I'll have to play around with links vs endpoints. Thank you all.

 

[Kris Flynn]

Thanks for the reply Mark, I was not sure what angle you were coming from, now I get you.

I am of the belief that a longer servo arm is easier to break the horn...which is not always a good thing!
There is obviously a point in the middle of "too long" and "too short" where you want to be.

As Mike said (i think he means this), the modern electronics have as much torque at 50% epa as they do at 100%...they certainly feel like they do anyway!

Cheers
Kris

 

[Daniel's Racing]

Any amount of EPA you take out is torque you threw out the window with too long a servo horn. You want the servo to rotate fully to turn only what you need.

If you are turning your EPA below 80% you really got it wrong and should be fixed.

Grim,
I disagree to the 9's. Can't believe you would post that you want the longest servo horn that will fit.
Strange idea's you have about things sometimes.

You always want the shortest servo horn position you need to get the rotation you need. Hands down no question about it.

If you are turning down your EPA you are wasting servo torque, battery power and wear and tear on your servo. You always want the servo rotating as much as you can. The servo is much better able to deal with rudder strikes too.

You can never be too short on servo horn if you can get the throw you need to turn the boat.

 

[Grimracer]

Its stretch for most and its OK if you dont agree.

I sleep the same.

Grim

 

[Daniel's Racing]

Its stretch for most and its OK if you dont agree.

I sleep the same.

Grim

Big stretch. Lol.

Seen a lot of these messed up setups with the 1 1/2" long servo horns China has flooded the market with and ever tom dick and harry selling them. People use them and trash their entire setup with them. Twice as long as they should be and there goes 50% of servo torque and increasing the steering speed by 2 times. Loose loose.

 

[Grimracer]

I understand that.. it looks and sounds funny.. its OK. Again.. just what might be best.. not gospel. You are welcome to do whatever you like.

Be well

Grim

 

[Grimracer]

There is more to this but again.. the longer the arm.. (i suppose I should add in tiller arm too) the least hysteresis. (Slop, play making up for shitty servo pots and the like).

It all has to fit in the box! LOL

I feel like i did miss type that.. no question its a balance. Mark is correct that Resolution trumps all.

Our servo options are WAY different then they were just 10 years ago. Our radio systems are WAY different then they were just a few years ago.. Some Futaba systems operate at 2048! (Full lock all in). We can take advantage of that.

O well.. I will back away and let the chips fall.

Got some boat work to do!

Grim

 

[Daniel's Racing]

Long at both ends is a different story. Equal the same thing mechanically but other advantages I get that perfectly.

Long servo horn and matching extended rudder horn is great but then side to side sweep of the pushrod gets excessive and you have the line drawn somewhere. On a outboard that this thread is about also does change the situation I understand so horn length is going to be way long to match the ones spread out on the outboard.

One way to make the rear long without being long is come off rear of rudder for the horn then you get the added leverage adding up going back and to the side but again it makes the pushrod side to side sweep excessive.

I thought you were saying on just any setup use longest you can fit. ????

I like to use the transom for a pushrod support and have only a hole the size of the rod along with smaller sized I.D. servo boot mounts so pushrod deflection is somewhat restricted. I use large diameter pushrods and monster nylon ball joints that do not ever get and iota of slop.

On the big gas outboards I use huge ball joints from real outboard engines throttle linkage. Made them in a 10-32 thread with 3/16 SS rod at one end and other slip over the SS rod then drilled and a roll pin installed.

Awesome gas outboard linkage.