New .12 Aggressor Catamaran

[Eric Perez]

Here is the new Aggressor Catamaran. It's ony 19" long still setting it up for action. It was radar clocked last weekend at 32 MPH but it was only pushing a stock X432 prop. I had been using an X435 without any problems. I'm sure that I can get it close to 40 MPH and still be stable enough for heat racing.

The plans for the "Micro" version are availble at http://www.microhydros.com

Tom if you are interested I can develop a special set of CAD plans for you to post at International Waters.

A build article can also be made available for those who show interest

I'm already working on the design modifications for the next generation cat hull.

Perez Boat Concepts

http://www.nitrotouring.com

 

[TomMoorehouse]

hey eric... how have you been? the cat looks great! I'd be glad to publish whatever you want with the boat... have you tried the v937?? what engine is that?

tom

 

[Eric Perez]

Hi, Tom. This has been my on going boat project for a couple of months now. The engine is my trusty Force 12 Red Head that I've modified for racing. The pictures show the engine with a Traxxas .12 water cooled head. The fit was not as good as I wanted so I ended up with the original air cooled head. The only modification that I did was to cut 2 cooling coils from the head. This way I can run the engine rich for extra lubrication, yet keep the head temps above 220F to wake the little mill up. New cooling heads are $12.00 at Tower so it's cheap experimenting.

I haven't tried a V937;Isn't that a lifting prop? Cats normally run better with low pitch non-lifting props. I have an Octura X435,Y535 and a Prather 215 that I'm going to try next.

Boat setups. I've been moving the CG foward to increase rough water stability I will continue testing today.

 

[Eric Perez]

Ran the boat last weekend again. It ran great! Not one blow-over, even had to raise the prop a bit to get the boat loose and fast.

Tested with the X435 but the Radar still showed the boat to be going 32MPH. The engine did seem to slow down a bit with the larger diameter prop. I'm going to experiment with a smaller prop with more pitch.

I just bought a 3.5 engine for use in the next project a 24" Cat. I'm still working the plans out if somebody wants to joing in just let me know I'll e-mail you the plans.

Eric Perez

http://www.nitrotouring.com

 

[TomMoorehouse]

have you tried the v937? might be too much prop??

 

[Eric Perez]

Okay Tom, on my next Octura order I'll pick it up. The V937 is supposed to be a high reving prop so maybe it will be the best one for peaky .12 power plants. I could always raise the prop a bit if it boggs the engine down too much.

Almost forgot tomorrow is my boat "play" day! I'm going to shorten the pipe a bit and prepare a 3/16 shaft for my larger props.

Once thing that I noticed with larger props is that the boat tended to stay flatter on the water, like it's putting more pressure in the bow of the boat, it makes sense. This might be the hot ticket for running the boat on rougher water.

PS. Any type of water condition is "rough" water for a 20" boat...

 

[Frank Bonanno]

Eric, Thats a neat little cat that you build.

why do you use a car pipe? mack has a pipe for the .10 and .12 engines that will give you the RPM`s you need for that engine in a boat.

 

[Eric Perez]

Frank I actually ran the MACs pipe last weekend. Killed both of my flex shafts and lost a prop... Testing did not go very good.

I'm going to remove some of the extra weight I added for rough water stability and see if it wakes up the hull! Plans are in place to install the 1HP Novarossi but I just hate lugging arround extra stuff to the pond, like starters and 12V batteries -The pull-start engines keep it so very simple.

I did try out some larger props and Octura X438 it really bogged down the engine. Maybe with a car tuned pipe the engine might be able to pull it but with the MACs it was struggling. It looks like the CAT's load the prop more than 3-point Hydros.

I'm running the pipe at 9" from the weld of the MACs header. I think total pipe length from center of plug is near the 9.5" mark. How long are you guys running the pipe with the X435 prop?

 

[Frank Bonanno]

around 7 3/4 from plug to widest part of the pipe in a 2 lbs rigger with the picco/trinity .12 STD exhaust.

the .12 dont make alot of low end power, you need the RPM`s to get the torque and HP out of them.

I would stick with the smaller props and keep trying to make more RPM`s, but thats me.

Also, the 1/8 flex shafts are not that durable, you need to keep them greased, we regrease them every 4 to 5 runs and have found that you need to have at least a 3/16" space between the strut and drive dog so that the cable will srink with out binding.

Also, when we were using the electric starter to start the engine the cable would rub on the stuffing tube and get so hot that when you launched the boat it would twist right apart at that spot, flaring the stuffing tube seem to help a bit but a solid engine mount is the way to go to keep the engine from moving wile starting and running.

these are some of the problems we came across, hope it helps.

Frank B.

 

[Eric Perez]

7 3/4" that's a real short pipe! I'll give it a try.

Frank, for whatever reason I seem to have the worlds worst luck with keeping the flexcable attached to the prop-shaft. I've tried soft solder and even silver soldering and have had best results with the soft solder... but every once in a while it fails at the worst time and I dump the prop!

What's the secret to keeping these two items from separating? I've heard of boaters never having to even worry about this -let me in on the secret.

This is what I use:

Octura .130 flex cable with a 3/16 to 1/8 step-down propeller shaft. I've heard of using engine sleeve cement from NAPA and even loctite thread lock "RED".

Does everyone just buy it pre-soldered?

Please tell me what's the secret?

Thanks

 

[Frank Bonanno]

Eric, the secret is, I use Hughey flex shafts ;D

 

[TomMoorehouse]

i've got to agree with Frank.... get a hughey and your probs will be solved.

 

[TimD]

Me too! I only use Hughey shafts.

Tim.

 

[hydroguy]

mee three, hughey shafts ;D