Dual Rudders on Pro Boat Mystic

[Garrett]

dh-prb4253
Impulse 31 dual rudder assembly anyone think this assembly will work on the Mystic?

[GatorsFan]

I too would like to know. Im thinking of modding mine some and would like the dual rudder setup and the use of two water lines

[gyrotron]

I too would like to know. Im thinking of modding mine some and would like the dual rudder setup and the use of two water lines

Here is Darin Jordan's reply on the topic. According to him it is not worth it.

"Here is the answer I gave to another user who just asked this same question yesterday... It could probably be done. Would take some fabbing... Not sure why you'd want to do that. It'll increase drag for little benefit. The MG/Mystic already turns like it's on rails..."

[Darin Jordan]

I'm not sure what the benefit of adding an additional rudder on the Mystic would be... It would add drag, weight, etc., with very little, if any, positive benefit.

What would the goal be that is making you consider doing this??

[gyrotron]

I'm not sure what the benefit of adding an additional rudder on the Mystic would be... It would add drag, weight, etc., with very little, if any, positive benefit.

What would the goal be that is making you consider doing this??

Well for starters the looks, I personaly like how two rudders look on a boat and then looking for additional stability. In theory is it correct to say that if you were to go with a dual rudder design, in order to lessen the drag, you would have to go with shorter rudders? I am just speculating on the subject. You are the Mystic Guru anyway so I'll keep it simple and stay with the stock single rudder.

[120man]

Funny you guys are talking about this and Im in the process of adding another rudder right now. Ive got another OE rudder and bracket on the way and by the way it looks I can just flip it over and bolt it to the left side. I havnt figured out exactly how to tie the two together for steering. Im thinking if I can find or make a threaded tube, I can screw it into the rudder where the water fitting goes and put a ball link on that, then a nut then the rubber tube. Im sure somebody can come up with a better idea on this.
I mainly needed more coolant running through as I am dealing with warm water temps, 80 to 85 deg, and equipment temps were unacceptable, even after opening up the cooling system. Thought about a prop wash pickup at first, but heard it would be more drag than an extra rudder. Im still considering a dual pickup rudder too. I was hoping cooler motor/esc temps will offset the extra drag enough to make it worth it. I hadnt read this thread before ordering the parts. Either way itll be fun to build it and look cool.


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[GatorsFan]

Funny you guys are talking about this and Im in the process of adding another rudder right now. Ive got another OE rudder and bracket on the way and by the way it looks I can just flip it over and bolt it to the left side. I havnt figured out exactly how to tie the two together for steering. Im thinking if I can find or make a threaded tube, I can screw it into the rudder where the water fitting goes and put a ball link on that, then a nut then the rubber tube. Im sure somebody can come up with a better idea on this.
I mainly needed more coolant running through as I am dealing with warm water temps, 80 to 85 deg, and equipment temps were unacceptable, even after opening up the cooling system. Thought about a prop wash pickup at first, but heard it would be more drag than an extra rudder. Im still considering a dual pickup rudder too. I was hoping cooler motor/esc temps will offset the extra drag enough to make it worth it. I hadnt read this thread before ordering the parts. Either way itll be fun to build it and look cool.


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water temps were the same thing that had me wanting to do it also so that i could add a second cooling line i may just add a pick up and line with out the rudder

[gyrotron]

Funny you guys are talking about this and Im in the process of adding another rudder right now. Ive got another OE rudder and bracket on the way and by the way it looks I can just flip it over and bolt it to the left side. I havnt figured out exactly how to tie the two together for steering. Im thinking if I can find or make a threaded tube, I can screw it into the rudder where the water fitting goes and put a ball link on that, then a nut then the rubber tube. Im sure somebody can come up with a better idea on this.
I mainly needed more coolant running through as I am dealing with warm water temps, 80 to 85 deg, and equipment temps were unacceptable, even after opening up the cooling system. Thought about a prop wash pickup at first, but heard it would be more drag than an extra rudder. Im still considering a dual pickup rudder too. I was hoping cooler motor/esc temps will offset the extra drag enough to make it worth it. I hadnt read this thread before ordering the parts. Either way itll be fun to build it and look cool.


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Have you guys seen the dual rudder system designed for the Impulse 31? I believe this system will fit the Mystic well. Here is OSE's and Proboat's links:

http://www.offshoreelectrics.com/pro...rod=dh-prb4253

http://www.horizonhobby.com/products...t-im31-PRB4253

I just installed it on my brother's Impulse and the boat rides beautifuly, gaining on stability and cooling (one rudder water pickup feeds the ESC and the other the motor).

[Garrett]

It looks to me that the Impulse brackets are just a little bit shorter than the mystic rudder brackets, therefore the rudders would be closer to the propeller, (not having these parts in my hands, and just by looking at pictures they look different). 120man I was thinking about doing the same thing that you're doing, adding another stock rudder and just flipping it, I'd like to relocate the water cooling hole thru the hull, and drill one on each side inside the rudder struts, for dual cooling, (one for the ESC and the other for the motor). [I live in Florida and the water here in the summer is 80 to 90 degrees, and the ponds are warmer.] I'd like to flip over the angled aluminum part for the steering, and use a small tie rod for the rudders. I just need to find some small longer bolts for going thru the right rudder.

120man - I'd leave the water hole alone, so that you dont block the cooling hose.

[120man]

Hey garret,
good job on your bro's impulse, any pics?
It seems the OE bracket flip will work. Got the parts and just mocked it up for now. I really like how it looks!
002.jpg 011.jpg
I was thinking about the steering brackets too, and it looked like a great way to do it, but I think that will throw the "geometry" off. Im thinking the pivot point of the linkage between the two rudders should be directly behind the rudder pivot. It seemed like if you use the brackets to tie the two together, the tie rod would end up inboard some, and the rudders wouldnt stay in line(parallel) with each other as you turn them. It might not be allot, but Im not sure.
Right now Im finding out if I can get parts made. Im not sure the threaded tube is the way to go, there are other options. Heres a not so pro drawing..
002.jpg
If I could find a water fitting with longer threads, that might work. A longer bracket (bolted where the stock bracket is) that extends straight back past the rear of the rudder with the link on it? or Maybe attach an "L" to the back of the rudder??
Id like to see how the dual works for a slalom. And at the beach in the surf. Im hoping the extra cooling will let me run all out in warm water conditions.

[dana]

Boredom?

[Garrett]

Gyrotron has the brother, I do not. lol. But I'd like the Impulse 31!

120man- I'm thinking that without any major fabrication you could just get an adjustable tie rod linkage and like you said install it where the water tube is. I was thinking about just under the silicon tubing.
dual ruddered mystic tie rod.jpg

[Garrett]

something kinda like this: dual ruddered mystic.jpg

[Darin Jordan]

something kinda like this: dual ruddered mystic.jpg

Make sure that wherever the tie-rod ends up, it's not in the prop blast... Keep it in front of the spray from the prop!

My prediction on this is that, when turning, this setup is going to drive the nose of the boat down into the water even more that it currently does with the single angled-face rudder.

I modified my Mystic 29 "Minus-Two" to accept the Impulse 31 rudder mounting system with the IM31 straight faced rudder. Lightened the handling up in the turns quite a bit going from the slanted rudder to a straight blade.

[120man]

Sorry about that, I was gonna make two different posts but forgot...duh
In your first pic, some water fittings with a longer threaded part would be ideal. I havnt been able to find any though.
The bracket method in the second pic looks like a great idea. Definitely the more you can get the tie rod outboard the better. It might be something you can put together and turn the rudders and see how it does. I know you dont want them to toe in or out too much or itll cause tons of drag. Look up "ackerman angle"
For now Im going to pursue the water fitting /tube option. Im going to call a local place that might be able to do the machine work. Still might end up a dead end. Ill keep you posted

[gyrotron]

120man,

I'll see what I can do about my brother's Impulse dual rudder pics. He took the boat with him.

I got pics from my brother's Impulse dual rudders. Here is what we did, take a look:

[gyrotron]

I modified my Mystic 29 "Minus-Two" to accept the Impulse 31 rudder mounting system with the IM31 straight faced rudder. Lightened the handling up in the turns quite a bit going from the slanted rudder to a straight blade.

Darin,
Where can we get the IM31 straight faced rudder? Can you post pics of your modified Mystic? Thx.

[Garrett]

what do you mean "minus two"?

[120man]

Great info- THANKS darin. Sure looks like the tie rod will end up right in the prop blast. Didnt realize the angled rudder drives the front down. At least I can say today I learned something.

[Garrett]

Hey, If you guys look at this, it appears that the tie rod is in the same position that I would have mine on the mystic. just an idea. but would like some feedback.
http://www.offshoreelectrics.com/pro...rod=dh-prb4253
Darin- Whats the difference between the angle faced rudder and the straight faced rudder? Could you post pictures showing the difference? in the pictures I'm looking at they look the same. Also, Dual rudders with a three blade (lifter) propeller. how do you think it would effect the drag, ride, hydrodynamics...etc

[Darin Jordan]

Darin- Whats the difference between the angle faced rudder and the straight faced rudder? Could you post pictures showing the difference?

The difference is that a straight rudder has a straight (up/down) leading edge... and an angled has a tapered leading edge. The later has a similar effect to cambering the rudder back (bottom further back than the top)... It pushes the nose down when it's turned (lifts the back). Cambering the rudder forward lifts the nose in a turn (sucks down the back).

The IM31 comes with a straight faced rudder. Here is a shot of the IM31 hardware on my Mystic 29 "Minus-Two" that I built to race at the Nats. The rudder in these pics is a modified Mystic rudder, but I swapped it out at the race for an IM31 rudder and it worked better in the turns...

[Garrett]

why did you take off the rear platform? was it to shave some weight?

[Darin Jordan]

why did you take off the rear platform? was it to shave some weight?

Hahaha... No... It was to make the boat legal to run in N2... 27" maximum hull length... Using the IM31 hardware, however, put the prop right back where it started, and I didn't have to tough the ride-pads to do this...


Here is the original thread: https://forums.offshoreelectrics.com/...uot&highlight=

[Garrett]

So Darin, do you think if I use the Mystic rudder strut with the Impulse rudders it'd have less drag? if so would the impulse rudder fit between the mystic bracket?

[Darin Jordan]

So Darin, do you think if I use the Mystic rudder strut with the Impulse rudders it'd have less drag? if so would the impulse rudder fit between the mystic bracket?

I don't know, and no, I don't think they are a direct bolt up... The setup I used above is ALL IM31 hardware, with the rudder blade only from a MG/Mystic, and that rudder blade had to be modified (cut out mounting and two holes drilled) to make it fit the break-away attachment/pivot for the IM31...

All of these factory rudders are a bit thick for my taste, but shouldn't really slow you down much. Just make sure to sharpen the leading edge. They are blunt from the factory.

[Garrett]

Good to know, Thanks Darin.
And guys, if you have anymore ideas on the topic please post them.
Pictures are awesome. Ill post my pictures as soon as I get my parts.

[Garrett]

IMG_20120828_172818.jpgIMG_20120828_174945.jpgIMG_20120828_175159.jpgIMG_20120828_175300.jpgIMG_20120828_175312.jpg

1st I put the two brackets on the hull, then Marked where the 2 water tube holes went, plugged the existing hole with marine grade caulk, then after it dried, I then installed the rudders onto the transom, along with the water pickup tubes, I got a Traxxas Jato Turnbuckle/Toe in Link, and thats how I tied the rudders together.

As for the ESC it had dual water fittings on it, so I bought some y fittings and split the tube.

[Garrett]

IMG_20120828_175351.jpgIMG_20120907_143756.jpgIMG_20120907_144146.jpgIMG_20120907_144157.jpg

[120man]

Excellent work, looks good. Let us know how well it functions. I was thinking if it tends to drive the nose down in a turn maybe you could tip the whole assy. back some to counter that.

[Garrett]

I finally got Mystified. lol. just a quick clip of how the boat ran with the new ESC and the dual rudders. Sorry for the short video, but I was holding my cellphone (Camera) in my right hand, and the transmitter in my left hand.
Theres a decent shot @ 1:14 that shows how the tie rod is positioned on the rudders.
http://youtu.be/byOIuE8YORQ