Lessen's Mini Cat

[Lessen]

Relatively short and sweet build here. I've been back and forth between a medium sized brushless boat and converting a small boat to brushless. I've decided on the later.

I'm going to go with the Proboat Mini Cat as the hull of choice. I figure the cat version will be a little more stable than the deep-v version which my boy has. Power will be from a Traxxas Velineon 380 system. The motor is only 1/2 mm larger than the stock motor so it'll fit perfectly in the stock mount. I figure I'll need to rig up a cooling system for that as well. I'm not sure on the steering servo or batteries yet although I realize the Lipo is the way to go although I have yet to add a lipo charger to my workbench.

Can anybody help a boating novice out with the cooling? What do I need to get the water to the cooling jackets? Is it simply a dip-tube and some fuel line? Are they generally force fed or pumped? Should I go 3S Lipo or would this little bugger be better off with some weight in it with a large Nimh pack?

Any help would be appreciated

 

[hamz9561]

I did some boats back in ancient RC history. The pick-up tube for the cooling system was behind the prop and that forced the water through the system without the need of a pump. Fuel tubing should be able to handle the water to and from the motor. You would just need to dump the water out the transom like on a 1:1 boat. The LiPo is the battery that I would use, I would just make sure that the CG is where it needs to be to keep the cat on plane and from pulling the bow up into a back-flip.

 

[Lessen]

I figure I can always add a few little lead weights if I need it to settle down a bit.

What's a transom? Sorry :shrug:

I also got to thinking.. Since the boat has the prop turning with the rudder I wonder how difficult it would be to add another servo and modify the rudder linkage so I could adjust the angle of the prop on the fly. That would be sweet and I don't think it would be too difficult either.

 

[Rolex]

The transom is the back plate where all the heavy hardware is.

http://www.offshoreelectrics.com/products.php?cat=66
You can pick up a good coil cooling system for $8.

 

[Lessen]

Thanks for the link Ralph! I knew you'd have some top notch help for me That water jacket looks like the best ticket. :thumbup::thumbup:

Any thoughts on needing to cool the ESC?? I imagine I should eh? It'll probably see full song quite a bit. It's a good size pond for these little boats.

 

[Rolex]

You can add a heatsink and run aluminum tubing through the grooves for water cooling if you think you need it. Mine is a biggie, so it's way overkill for what you need.

My ESC has the twin fans and the heatsink, and the motor has the cooling fins and a water jacket.
I'm pretty sure you can get an ESC that's specifically made for boats and has cooling tubes built in.

 

[Lessen]

something like that would be a cakewalk to make anyways. If I run 3S I think I should probably cool the ESC somehow. As I mentioned, I'll be using the Velineon VXL-3M speed control. I'm not sure if the block of cooling fins can be taken off but I think I can do something with it even if not. I'm looking forward to this and Chase is really driving me crazy with wanting to drive his boat (it's gonna be a looong winter)

Ralph, are there any cats out there that have adjustable prop pitch or is that something you only see on v-hulls?

 

[Lessen]

OK, nevermind on the adjustable pitch. I just watched a video of an 11.1v brushless Mini-C and the thing seemed plenty stable (surface was glass). I guess Nimh is certainly out. Time to upgrade to a better charger Can anybody school me on props? This guy is using an Octura x427 but I was just kinda wondering what the real world difference is between one prop and another.

This thing is sick fast.

 

[slowngreen]

That little bastard runs good! Thats a cool spot too, is that a canal?

 

[Rolex]

Wow, that has the take off of a drag boat!

If you use out drives, you can adjust the prop pitch. Tough call on the smaller boats. Most of the sites I have bookmarked are for the big ones, but the hardware gets really expensive.
Without out drives, you have a choice of shaft drive or cable drive. Cable gives you more options for mounting your motor and prop at different angles to get the desired effect.

 

[Extreme RC Mods]

I did a little looking and found this thread, it may be useful to you.

http://forums.offshoreelectrics.com/showthread.php?t=2245

If you don't already know, you need to dress a new prop yourself and the X427 is made of beryllium copper, the dust if very harmful. I have not used him yet but have heard many good things about his work, he will send you a RTR prop for a very decent price considering. Just send him an email with what you have and he will give you what you need, so I'm told.

http://testing1477.freehostia.com/Propshopprops.html

 

[Rolex]

Here's some help for a first time cooling system set up.

http://www.customgasrcboats.com/how-to-add-water-cooling-to-your-rc-boat/

My setup has 2 of the curved pickups since I'm running a pair of E-Savage motors instead of the brushless in the catamaran.

 

[Lessen]

Thanks for all the links fellas! That thing about prop balancing will be helpful. I don't know jack about that.

 

[gnarkill]

Thanks for all the links fellas! That thing about prop balancing will be helpful. I don't know jack about that.

Balancing isn't that bad to do, it's just time consuming.


Smooth the edges out then use a prop balancer (I use a airplane prop balancer) and which ever blade is at the 6 o'clock position, You file some metal off of the backside of the prop it until the two blades are at 3 and 9 o'clock.

They don't need to be perfect, but the better they are the longer the strut bushings will last.

 

[Lessen]

thanks for the tip gnarkill. I might try it out for sake of learning something new

 

[Rolex]

Here's the setup I made for the Villain IV which was not cooled. I cut a set of Traxxas heat sinks and installed the water coil between them. Pickups were underneath, and blew out by the props.

You can see the aluminum tubes (like exhaust pipes) to the outside of each drive.

 

[Lessen]

So you wrapped those coils yourself Ralph?

 

[Rolex]

The coils were the only part of the system that was stock. They were made to fit a 540 size motor. I think both coils were $18 and the plastic tubing you can get in any hardware store. Each motor has it's own supply rather than running both with one feed.

 

[Lessen]

Ahhh.. that way they both get the same temp water coming in. Nice.

 

[Nitrobuzzard]

Thanks for posting that vid bro!! sheesh...looks like another project for me now...that thing is wicked LOL Guess I'll have to start finding a boat that'll look right being pulled by my Maxx.....dang..I knew better than to start into this hobby again! LOL

-Nitro