Twin powered carbon Rivercat build

[dmitry100]

Btw, wouldn't you have alot more space in the overall motor's length area if the motors mounts were not mounted so much at a downwards angle? Or is that done to keep water from coming out from the stuffing tubes?

Also, are you using any particular kind of servo rod there for the rudder... is it a typical 2mm in thickness rod?

[kfxguy]

Btw, wouldn't you have alot more space in the overall motor's length area if the motors mounts were not mounted so much at a downwards angle? Or is that done to keep water from coming out from the stuffing tubes?

Also, are you using any particular kind of servo rod there for the rudder... is it a typical 2mm in thickness rod?

1) the motors are as low as I can fit them. As a matter of fact I had to clearance some epoxy because the cooling jacket was hitting. The motors have to be at an angle, if they weren't, you'd never get the flex lined up unless you did an s bend. I'm not a fan of s bends.

2) for mockup I'm using a 4-40 rod. I'm likely going to be swapping that out for a thicker rod. I do have some carbon rod but I have to have a slight bend in the rod so carbon will not work.

[srislash]

I think you will love the twin. Have you considered what props you will be running yet?

And on this note, I do have a few prop choices here if you want to try them Travis, 4019/2, 4019/4, 4217/3, 4513/2, 4518/2... May have a few more but I am just throwing them out there buddy. Just letting you know you can try em.

[kfxguy]

And on this note, I do have a few prop choices here if you want to try them Travis, 4019/2, 4019/4, 4217/3, 4513/2, 4518/2... May have a few more but I am just throwing them out there buddy. Just letting you know you can try em.

Thanks buddy! I'll let you know if I need anything.


Should I run seperate cooling lines or can I split them? I plan on drilling the fittings for mor flow and using larger line. Thoughts?

[kfxguy]

Getting it wired up. Checked the Cg again and it's sooooo close to what I want it at. I think once the trim plate and flexes are added, it will be dead on. Hopefully. Lol.





Of course the wires will be tidied up but this shows the layout. I wasn't sure how I was doing it until tonight. Winging it I guess on this part.

[srislash]

I would think splitting the cooling lines would be adequate Travis. I usually do thru hull pickups for each side but I am talking larger hulls here. At first look it looks like you would have too much rear CG there but then your packs are going to be hefty for this size hull. I found 32% right on the Fantasm with the ABC's but there is a ton of neg dialed in as well.

[dmitry100]

kfxguy: How do you check Cg ?

[kfxguy]

kfxguy: How do you check Cg ?

Well I've always been a build it how everything fits kind of guy but when you try to approach high high speeds, little things like this make a difference. So I put it on a 3/4" round rod and measure where it balances.

[dmitry100]

What kind of water jackets are those? They look like some nice heavy duty ones.

Was actually thinking to upgrade the TP jackets I have for better cooling... I think those 1715 props might be heating things up like the 448's. (Clocked about 87 mph first them with them btw on the short distance run using a 10hz refresh Garmin Glo). :)

[kfxguy]

What kind of water jackets are those? They look like some nice heavy duty ones.

Was actually thinking to upgrade the TP jackets I have for better cooling... I think those 1715 props might be heating things up like the 448's. (Clocked about 87 mph first them with them btw on the short distance run using a 10hz refresh Garmin Glo). :)

I have 36mm motors so keep that in mind. I get those jackets from the ose store. Second page. They are for a fiago motor or something weird but they work perfect.

[dmitry100]

kfxguy: What are those carbon fiber looking jackets you sometimes use? Do you custom make them yourself?

[kfxguy]

kfxguy: What are those carbon fiber looking jackets you sometimes use? Do you custom make them yourself?

I made one out of carbon tube once and mostly it's very thin carbon that I epoxy around a cooling jacket. I was thinking about doing it on this boat.

[Fella1340]

Looking great Travis. How do you like building a twin versus a single? You mentioned the carbon fiber sleeve awhile back. I sent that to you after your second build. I was wondering when it might show up in a boat. I thought they may be more trouble than there worth, make sure the tube is already black before using or you'll be seeing gold through the sleeve fabric.
I'm excited for you on this build, you've pulled almost 100 with a single. Will double the cost and work of twins be worthwhile on this size cat (for sport running). You could do a comparison, say you hit 110 mph, what did each additional mph cost over your previous best as a single. I could see it getting into the $100 plus for each additional mph. I hope you end up liking twins a lot, you can really start pushing the envelope then!! You are a boat building machine, keep it up😀. Sorry for rambling so much, not really.

[kfxguy]

Looking great Travis. How do you like building a twin versus a single? You mentioned the carbon fiber sleeve awhile back. I sent that to you after your second build. I was wondering when it might show up in a boat. I thought they may be more trouble than there worth, make sure the tube is already black before using or you'll be seeing gold through the sleeve fabric.
I'm excited for you on this build, you've pulled almost 100 with a single. Will double the cost and work of twins be worthwhile on this size cat (for sport running). You could do a comparison, say you hit 110 mph, what did each additional mph cost over your previous best as a single. I could see it getting into the $100 plus for each additional mph. I hope you end up liking twins a lot, you can really start pushing the envelope then!! You are a boat building machine, keep it up��. Sorry for rambling so much, not really.

Had I remembered I had that sleeve you sent me before I epoxied in the first tube, I would have used it. I tried it an an experiment on a piece of brass and the weave on it is thick enough you don't see brass through it. Honestly this build cost me less that a high end single build. These motors are cheap and so are the escs. It definitely cost me a lot less than my last Rivercat. That motor in there was $450. At this point if it does 75-80 I'd be happy. That's all I expect out of this setup. If the boat is stable then I will move forward with getting more out of it.

[keithbradley]

Dude, you're going to love this thing. When comparing a single to a twin, don't think in terms of speed. After all, the FASTEST official record by an RC boat is held by a single motor/prop machine. Single prop boats are actually more efficient than twin prop boats, in the same manner that 2 blade props are more efficient than 4 blade props.
However, using two motors helps to unload the boat and make aggressive setups more reliable and "sport" worthy. It also completely changes the way a boat handles and accelerates. Nothing drives like a TWIN!