Twin outboards power trim / jackplate

[fotis zzr]

New to this forum, new also to rc boat hobby.
I am coming actually from crawler / scale area but always I wanted to build a boat with twin outboards.
Since I have no idea about the right trim / height of the outboards I said, why not to make a try and built something like the actual size designs.
After some months of do - undo process, brainstorming and re design again and again seems that I managed to be somewhere.
Please share any ideas or improvements you may have to make this project better and functional.

Fotis

[sammyha]

Very cool! With any outboard setup, the concern is aft weight and getting CG correct on the boat. Could you extend your linkages to locate the servos more forward in the hull?

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[fotis zzr]

Very cool! With any outboard setup, the concern is aft weight and getting CG correct on the boat. Could you extend your linkages to locate the servos more forward in the hull?

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I will need a lot of advise from you experts when the time will come and the outboards will move at the boat.
The next step is to have all the parts from CNC, plexiglass first, aluminum at the end.

[fotis zzr]

https://www.youtube.com/watch?v=TwQ8GoTL0YQ

[Panther6834]

That is totally cool...and, for being your "first", that makes it even better.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[fotis zzr]

This rib will be the partner of the outboards.

http://www.modelmast.de/zdjecia/Zodiac%20H920.jpg

[Dirk Jan]

Very cool project! Are those twin MHZ outboards? That hull must be quite big. I'm following

[Panchothedog]

Very nice work sir. Extremely scale in movement. With the weight of batteries and speed controls, and the ability to move them about the hull,
I don't think you need to worry about the weight of 3 servos being close to the transom. You got it working good.

[fotis zzr]

Very cool project! Are those twin MHZ outboards? That hull must be quite big. I'm following

The outboards are coming from Graupner Germany. Not in production any more.
Bought them together with this cat like a bundle
https://www.diamond-models.gr/rc-boa...t-900mm/?sl=en
The rib coming from Poland, modelmast is the name of the company http://www.modelmast.de/Komplettbaukasten_GFK_nie.htm , move down to Zodiac Hurricane for some specs. The hull is made from fiberglass, 72cm long, around 1,8kgr of weight empty, too heavy I am afraid.
The purpose is the scale look and not the top speed so we will see.

[fotis zzr]

And thanks all of you Gents for your nice comments

[fotis zzr]

Inspired from Chris ����, he is using the same hull.
https://www.rcgroups.com/forums/show...y#post45856671

[sammyha]

Very nice work sir. Extremely scale in movement. With the weight of batteries and speed controls, and the ability to move them about the hull,
I don't think you need to worry about the weight of 3 servos being close to the transom. You got it working good.

I would say servo weight will def be an issue in a boat that small...

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[Panchothedog]

Now that he has revealed the length your point makes more sense. Neither one of us knew hull size when we made our statements. Looks like a lot of
weight to hang on the back of a 30 - 32 inch hull. Worse yet, looks like the battery box is at the very back part of that hull.

[fotis zzr]

First try on boat with double side tape.

[Panther6834]

Looks scale as heck...but, the rear weight issue could still be a problem.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[fweasel]

Looks spot on!

[paulejr]

One could, weigh everything , includig the hull all up and take a look at how the weights sit in the hull. placing them to get the boat flat on water and then move parts and pieces fwd and aft to see where it likes to sit under way. With your rig , trail and error is the watch word today.

[fotis zzr]

I am thinking to cut and modify the deck because of 2 reasons:
1. center of gravity issue
2. I would like to have a center console rib design
I am going to leave a bit of the vertical part ( follow the marker lines ) just for stability of the hull.
Any thoughts / suggestions ?

[Panchothedog]

You are going to have to figure out a way to get the batteries farther up towards the bow in order to balance it properly. Might end up altering the current layout of the deck. I don't think you have any choice.

[fotis zzr]

Since there are no more suggestions apart Pantchothedog’s -thank you my friend- I have made some mods to the hull the last days.
Servos are mounted in a temporary plexi. All movements seems to work fine.

[fotis zzr]

82B30967-A8B7-4CDC-A520-0DAA2C1859C1.jpg16CBB8BE-4678-4C78-B962-6B6AADCD5D49.jpg41101440-FA9D-4F10-BDA3-D433D7B65422.jpg

[fotis zzr]

There is enough space around 18cm to move batteries to the front 1st picture and close to the middle of the boat 2nd picture

[fotis zzr]

857B8FBA-6FEB-49C0-B41B-BD63F90326BE.jpg9592DFA8-BF39-420C-9BB5-1893B5BD2C66.jpg

[fotis zzr]

So now that CG considered like no issue any more I would like to ask about the proper height of the outboards.
is there any golden rule ?

[Panchothedog]

For Tunnel hulls powered by outboards looking for top speed the center of the prop is usually even with the bottom of the sponsen. I think you will want your props a little deeper. Maybe the top even with the deepest part of the hull for starters. Might end up taking some experimenting, especially since you are interested in scale appearance more than speed.

[fotis zzr]

Thank you for the input. I think that Tunnel hulls require different setup than the deep V hulls.
In any case the travel of the jack plate is approximately 25mm so I believe that somehow we will find the right height.

[fotis zzr]

The lowest position The middle position

0-02-05-49b23a54fb36f346e742a985c866a1be75275ea0cf0a4e88fef72f460de93c68_66289381ef63ce99.jpg0-02-05-7d7546580f36846331a9be0d0072eebc46a390eb1692b6e6a61f5ba59788f813_c5ea4dd297822e13.jpg

The highest position
0-02-05-f943a5003ad9716c035ad842d05b2d2943f13afa9ebaf40be89f13f59e3fee88_6939e8fa7df9f75a.jpg

[Panchothedog]

With 25mm (about 1 full inch) of up and down travel, I feel you have enough movement to find the " good " place. You might even be able to start deep, and once on plane trim them them up a little just like a full sized outboard powered boat would do.

[BUMBLESPECIMOODA]

I love a scale build.