Twin outboard install, Fine design 32.

[RaisedByWolves]

I started my twin outboard install on this hull after waiting for my linear actuator to arrive for my power trim setup.



The hull.



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The actuator arrived and I got started, but the actuator is was a bust. In communication with the MFG now to try and resolve the issue and I hope I just got a bad sample as it looks like a really nice unit.


Anyway,I started on making a unified tilt strut to hold both outboards and simplify the tilt alignment.

This is as far as I got between jobs at work friday. Not a bad start. Both of the motor pivot shaft holes are in and everything is squared up with some preliminary saw cuts to remove the bulk of the unwanted material.

When complete it should look similar to the drawing.


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[MadProps]

nice, what outboards are you going to use

[RaisedByWolves]

I picked up a pair of Aquacraft EP1's for cheap so Im going with those for now.

Im not really looking for all out speed, just a decent scale + boat to mess around with. Maybe 30mph top speed.

Hopefully the fun in this one will be the ability to run it well in all conditions as my favorite spot is on the windward shore of a good sized lake. Some of my other boats dont do so well in heavy chop so with this I wont get skunked when I go out if its windy.

[MadProps]

I really like your trim idea

Im building my first scratch build, with twins at the moment as well, but after seeing this Im pissed I didnt do trim ....grrr
I may just stop and regroup,

I will start my own thread and post close ups of what I have done , Im open to engineering suggestions, hope you look in

[RaisedByWolves]

Yeah, I'm watching your thread and the steerable drive thread also.


I purchased a linear servo to use as thdrive for the tilt function but I'm having issues with it's resolution. It is an Actuonics pq12r rated fo11lbs of force which is great but so far I can't get it working satisfactory.

I'm talking to their techs now to come up a way to resolve my issue's.

Who knows, maybe I got a dud.

[MadProps]

hope you get it resolved
I think I have a viable approach to trim my setup using what I have already....just need to think it thru a bit more

[RaisedByWolves]

Do you have an idea as to how you're going to power your tilt/trim?

I bought a linear actuator from a compant called Actuonix a PQ12R but Im having issues with getting the resolution I want. It seems to be operating in oddly spaced steps of almost 1mm, which isint optimal. I took a video and emailed it to their techs and am waiting for them to decipher it. Hopefully I simply got a bad sample as it is a nice, small, strong package. 11lbs of force @ 6v.


This is all the farther I got as I actually had to do work for the company at work today.

So far so good on the mount, but the wiring may be a bit of an issue.


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[MadProps]

Do you have an idea as to how you're going to power your tilt/trim?

sorry it took a while to get back to you ....I decided Im really not concerned with tilting the motors full up, and it will be an easier mod to just add adjustable trim for performance......I have so little travel with the stock trim adjustment and so little trim adjustment really required with a surface running prop, I am pretty sure I can get away with just a servo and pushrod that I will connect to a bracket that I will have to fab up that will mount on the 2 inside steering control arms on the motors that Im not using. I also will use a servo speed limiter to slow down the trim travel, when Im in my hydro I can hear the motor and feel the boat respond when I trim it out, since I cant do this with the rc boats and the servo movement is so fast and I have so little travel available I fear I will be constantly searching for the correct trim position because it will move so fast and go right past my optimum trim position.... it wont be as easy for me to judge watching remotely so trim speed reduction closer to scale will be a nicer mod..... just my thoughts how I will approach this, we will see how it works out

edit: this is the speed controller I use for flaps in my planes that I will use to slow down my trim
ssdriver.jpg

[RaisedByWolves]

Ive often wondered whether a servo alone would be strong enough to maintain its position under load with something like this. I did see where a guy used a continuous rotation servo and a screw arrangement, but i have no idea how he controlled it.

I dont think Im going to pursue tilt either unless it just happens to work out. I have an idea how it can be worked in easily if everything aligns but its not my main goal.

I got some more roughed out today. The L shaped bracket will be the pivot for the trim and also the jack plate. The two tabs sticking up off of the motor bracket will be the pivot points and the jack plate will be slotted to accept them and they will be pinned.

Most likely 50-60% of whats here will be removed. its just easier at this stage to leave everything square and wide enough to give me room between the part and the milling vise to work where I need and still have enough material to grip it. Once I get down to the finer details I can start cutting everything unnecessary away.


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[MadProps]

Ive often wondered whether a servo alone would be strong enough to maintain its position under load with something like this.

I thought about this and decided that Im willing try using a metal gear high torque servo and if it fails I only have a small hole in the transom for a push rod to fill .
had I thought about trim before I got this far in the project I would have gone another direction Im just not willing to scrap what Ive done and spent so far for this mod...... I have dual thru hull water pickups I would have to work around etc etc etc .....we will see how it goes

[MadProps]

whats the torque of your linear accuator in comparison to my servo
Torque: 208 oz/in (15 kg/cm) @ 7.2V 4.8V 6V Speed: 0.16 sec 0.14 sec

[RaisedByWolves]

The two different types of ratings do not really cross over.

Torque on a servo would be measured looking down on the servo shaft in a rotational plane. The linear servos simply transmit force in one direction or the other. You get a linear force from the servo by making it move the rod with the servo arm, but the amount of linear force varys depending on how far out on the servo arm the rod is attached.

Clear as mud?



I got the motor mount pretty much finished today including the pivot pins which I turned out of some stainless bolts we had laying around.

Not really a finalized shape as of yet being as I dont know if my actuator will work or I should say how well it will work, but its enough to let me get the motors mounted and start making up linkages and other stuff. The pivot pins wont be pressed home until the final install.


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[MadProps]

its taking shape nicely! how do you intending sealing the actuator thru the transom area

Clear as mud?

I get it a fairer way to compare would be measure the foot pound force at the end of the servo/pushrod set up

[srislash]

That mount/pivot plate looks great. Nice job. I love the ingenuity. Adjustable trim for rough water is an awesome idea. I have always wanted to do a F1 tunnel hull with trim.

Madprops, I would think a rock crawler servo with 400+ oz/in May be enough. Or maybe a Retract servo? Be a slower speed too.

I have a bit of experience with the stronger servos and adequate power has to be supplied as they can have over 5amps stall.

[MadProps]

That mount/pivot plate looks great. Nice job. I love the ingenuity. Adjustable trim for rough water is an awesome idea. I have always wanted to do a F1 tunnel hull with trim.

Madprops, I would think a rock crawler servo with 400+ oz/in May be enough. Or maybe a Retract servo? Be a slower speed too.

I have a bit of experience with the stronger servos and adequate power has to be supplied as they can have over 5amps stall.

excellent idea thankyou , I will give one of those servos a try, Im not cheaping out from buying an actuator, again I was so far into my build with twins before I discovered this great post and trim for RC outboards... I am just limited in transom area space or I would jump and buy 2 liner actuators, and hinge my setback plates