Twin Outrunners on a Hydro?

[Dangerous_Toys]

I have a project I am thinking of going twin drive with. It's a 51" FG Shovelnose Hydro. I want to use the Little Screamers outrunners. Can outrunners operate in a reverse direction? I am thinking counter rotating props. If not, I would assume I could go twin drive with the same rotation on the props as well? Any help would be great! Thanks in advance!!

[siberianhusky]

Flip any two wires on the motor and it will run in reverse, the esc controls the timing of the motor, not like the old brushed jobs where you had to turn the endbell to change the timing by changing the relationship between the brushes and magnets.
We used to break in sealed stock motors under water to quickly seat the brushes and get as much timing as you could. Makes sure the entire face of the brush was in contact with the comm.
For Brushless the esc controls the burst of current going to the armature, it can make it happen as early or as late as programming allows in relation to the magnets.
Make sure you use a cable with the opposite twist for the one that runs reverse!
Never seen a twin hydro, riggers yes, not sure it would be much faster for the added cost and problems. The only boats in 25 years I've seen that work well as twins are cats and riggers, twice the cost and usually only a few mph faster.
Thats a damn big hull though so it could be an interesting solution.
Admittedly new to electric but been running nitro since the early 80's, I'm not yet sure of the limitations of the motors and esc, Starting out with a sane setup in a 29"mono as I gain more experience I'll start pushing it.
I have a pretty good technical background and used to race 1/12 pan cars indoors during the winter back then, thats the only reason I know about the above esc and motor stuff! No clue yet as how how you actually pick an electric motor for a boat!

[Dangerous_Toys]

I'm not really looking to get more speed, I was hoping to get more torque to push that hull. I was thinking one motor might even lighten the load on the other. Not sure if the twins will make any difference as opposed to a single drive. As for motors, i was thinking of using a Little Screamers Outrunner or a Scorpion Outrunner.

[siberianhusky]

Just thought as well it might lift the stern too much with two props, I honestly don't know enough about electrics to know if it would really do much. Almost all my experience is with nitro and we're always after speed!
The same amount of water is being moved at say 50mph regardless if it is one or two props moving it. Stands to reason that you would draw less current from two motors sharing the work load. I just don't have the experience to say how much less and is it enough to justify two of everything.
My opinion as far as nitro goes is that it is more show than go! Two engines sharng the load allows them both to spin a bit faster but your props are still doing x rpm and have x pitch so they are moving forwards only that amount, you don't magically get 50,000 prop rpm as opposed to 27500, you might pick up a some rpm and that is where the total speed increase happens. Might be able to run more pitch as well.
LOL I'd be better off if I was a better driver!
Going to keep an eye on this! Think I might learn something!

[Dangerous_Toys]

Thats why I am fishing for advice. Hopefully I can get pointed in a direction that would be beneficial for this build.....

[LarrysDrifter]

I know that twin motors operate more efficiently than a single.As well as the benefit of sharing the load.I dont know for a fact,but I dont see why you couldnt run one LS in reverse.We do it with inrunners.Just swap two of the 3 esc wires.But,one problem you might not have thought of is the available props to take advantage of the LS motor.There arent that many reverse rotation props to pick from.As far as using the same rotation props for both sides,its not adviseable.Ive heard of people doing it,but the boat tends to pull one way when running it.Your also gonna need to round up a big reverse rotation flex,unless you use big wire drives.My opinion on a flex is .187 minimum.Hope this helps.

[blackcat26]

I thought about and may still build a twin hydro. Having counter-rotating props might make her not want to turn as well. I have wondered if two same direction props might walk a bit but would turn better??? It's on my list to make a "twidro" but gonna be awhile.

[don ferrette]

My opinion as far as nitro goes is that it is more show than go!

Have you ever run one? I've raced nitro twin riggers for years as well as set records with them and while it's true they aren't much faster than a single as far as top end goes, the sheer power "out of the hole" punch is outrageous and the adrenalin rush is the bomb!! Running any kind of twin is not for everyone and takes a high level of attention to detail combined with the ability to tune one but when it's right it will take you breath away. I have found it a tad amusing that those I've gotten to know in the FE world, who know of my twin nitro exploits, are asking me how soon there will be an FE twin in my stable since I've crossed over...........

........knowing how I am I'm sure it won't be long.

Twins ROCK!

[siberianhusky]

In 25 years of nitro running and racing I've at least driven just about every style of boat out there, and in MY OPINION they aren't worth it. Sorry if that hurts your feelings. But I stick with what I said, not enough speed difference to justify the hassles. You even agree they are not much faster! Impressive looking, technical yes a pair of synched nitro engines synched does sound awesome but.....
Last one I got to drive was a scratch built rigger with a pair of OPS 11ccs in it, a guy in the club had it for a short time then parted it out because nobody else wanted to build a comparable boat to run against his. Turned it into 2 single riggers.
To each his own as long as we all enjoy the hobby.

[don ferrette]

In 25 years of nitro running and racing I've at least driven just about every style of boat out there, and in MY OPINION they aren't worth it. Sorry if that hurts your feelings. But I stick with what I said, not enough speed difference to justify the hassles. You even agree they are not much faster! Impressive looking, technical yes a pair of synched nitro engines synched does sound awesome but.....
Last one I got to drive was a scratch built rigger with a pair of OPS 11ccs in it, a guy in the club had it for a short time then parted it out because nobody else wanted to build a comparable boat to run against his. Turned it into 2 single riggers.
To each his own as long as we all enjoy the hobby.

Feelings hurt?? Not hardly and to each his own. No problem at all with you "sticking with what you said" as apparently twins are something you're just not in to. Twins are not for everyone and typically those who find them "to much hassle" don't possess the skill level and/or attention to detail needed to make one consistently peg the fun meter (sorry if that hurts your feelings). I love the twins and find them absolutely no more "hassle" than a single and will run one of mine any chance I get. Again to each his own and we all have an "opinion" but if someone wants to try their hand at one be it nitro or FE don't try to talk them out of it right off the bat simply because it's not your particular "cup of tea", they might find it pegs their fun meter as well.

[siberianhusky]

LOL not at all, all good. LOL I'm only good at two things, playing guitar and mechanical things. Makes no difference gas, diesel,glow I just have that engine "thing" and perfect pitch! I can really hear the harmonic dissonance in a pair of engines that are running out of sync. I can do the same with a pair of electric motors in a boat hull, I hear the resonance of the hull when the motors are not turning the same rpm.
Most people can hear it to some extent unless you're completely tone deaf, to a person with perfect pitch it's a very unpleasant feeling.
Cheers, Have a great day, go rip up some water with those riggers, they're all fun not matter what makes 'em go!

[don ferrette]

LOL not at all, all good. LOL I'm only good at two things, playing guitar and mechanical things. Makes no difference gas, diesel,glow I just have that engine "thing" and perfect pitch! I can really hear the harmonic dissonance in a pair of engines that are running out of sync. I can do the same with a pair of electric motors in a boat hull, I hear the resonance of the hull when the motors are not turning the same rpm.
Most people can hear it to some extent unless you're completely tone deaf, to a person with perfect pitch it's a very unpleasant feeling.
Cheers, Have a great day, go rip up some water with those riggers, they're all fun not matter what makes 'em go!

Yessir all good. Guitar? What music preferences?? Used to play bass 'til I broke both wrists back in the early 90's. You have an awesome day too.

[Simon.O.]

I will agree that twins especially in my cat are a lot more work for a little if any more speed.
The sound is amazing
The acceleration is eye opening

Twins in a hydro just should happen. Look at top drag hulls, twin props for the most insane launch there is. That is a long term target for me.

I fully agree with a twin FE hydro for fun, if you do not build one now then all the folk here will have to wait a while before I sort my coins to do one.

[Dangerous_Toys]

Well i think I am gonna go with single drive. A Scorpion 4035 800KV Outrunner, Swordfish 240HV ESC on 10s to start with. 12s later on. Now should I go with a 3/16 flexcable and shaft or 1/4?

[Fluid]

Use 1/4" cable, absolutely. You will eventually break a 3/16", but the 1/4" will be pretty much bullet proof.

BTW, twin-motored R/C race boats almost always run both motors the same direction. Why? They don't want to turn with counter-rotating props. Turns out the prop walk is critical to good turning, and of course prop availability is a factor too. As Don states it is the acceleration out of turns that is so awesome when watching the big nitro riggers run. If you can keep both motors lit they must be a hoot to drive.


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