.15 Nitro Aggressor 23" Cat

[Eric Perez]

.15 Nitro Aggressor 23" Cat

Well, now I'm back hot on the trail for a new CAT hull design.

This one will be based on my Nitro Aggressor 19" design but will be 22-23" long. The cord length will be a hair under 24" because that as long as I can get wood at the LHS...

The hull will utilize HC sponson design both on the top and on the bottom. The riding surfaces will have no dihedral and will be quite narrow(3/4" to 1"). The Hammer Cut will be setback from the front as to provide a natural stumble block for the hull to prevent the narrow spoon from diging in on the corners. I'm not sure if this feature will be needed -it can be removed with a sanding block

The outside of the spoons will also be 90. The tops will have a crown leading into the HC.

The radio box will be a separate unit that can be removed so that the water can be drained from inside it ;D

The fuel tanks will be set just behind the CG to move it forward a bit to help the hull as it lightens up. (2) 3-4 oz tanks will cradle both sides of the engine. I found that if you want to "add" weight to a hull near the CG then fuel serves this purpose well.

What do the great rc boating minds think?

 

[Ian Inverarity]

Re:Hull Ideas for Nitro .12 Cat

Eric,

I am no expert in cat design, but that looks good to me! 8)

Check out these pics of the underside of the new Insane gas cat. It is supposed to work pretty well and has just set some oval records. Note some sections that appear similar to the Hammer cut idea.

www.insaneboats.com/cat8.jpg

www.insaneboats.com/cat7.jpg

What is your opinion on steps? I note your design does not feature any.

Ian.

 

[waterbug]

Re:Hull Ideas for Nitro .12 Cat

I noticed those same cuts on a full size SST 120 !!!

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

As far as steps on the bottom of the running surfaces? I'm not too hot on steps. I just don't build enough hulls to be able to get the steps in the right place. I feel steps in the wrong place or with bad geometry are worst than no steps at all.

If I built a dozen of the same hull with steps in different places -Then I can see how it could be a good thing. I only build a couple of scratch hulls a year 3 at most. So it would seem like an unrealistic target.

If I get gun ho about steps, they can be cut into the bottom spoons with a sanding block without a lot of work. I really like the bottom of the Insane Cat, looks more functional than the other boats with scaled down steps.

I'll get a couple of views uploaded for the bottom and profile of the spoons tonight.

This cat hull is very low-profile the tub/engine section ins only 2.25" tall, the engine will be air-cooled

 

[_laxmasta2039]

Re:Hull Ideas for Nitro .12 Cat

eric,

i've built one of Jay Turner's XS cats before and thought it would be a good thing to go nitro with [25" long, stepped ], the only reason i didnt was it warped and the finish really sucked. i've still got some pics of it before it "went bad" though, ya might wanna take a look when you're considering steps/wedges, and also it's got an air vent that might be a good idea if you're going to use an air-cooled engine. tell me if you'd like pics,

Joe

 

[Altimat]

Re:Hull Ideas for Nitro .12 Cat

What is HC sponson design? I searched and found nothing.

 

[Propjockey]

Re:Hull Ideas for Nitro .12 Cat

"Hammerhead Cut"

 

[Altimat]

Re:Hull Ideas for Nitro .12 Cat

"Hammerhead Cut"

Yeah I got that part!

 

[Propjockey]

Re:Hull Ideas for Nitro .12 Cat

Sorry Dude, my bad. ;D

Hey Hammer, can I borrow a pic? Thanks!

OK...see the chunk hacked out of the outside edge of the sponson? (well, it's the inside edge here, but it's upside down.......the sponsons, not the picture. The bottom is.....well, see there's four.................oh, you get the idea!) ;D

The 'Hammer Cut' An International Waters (and Hammer's) original exclusive. "It's a household name" -- Forrest Gump

It looks good if you use the 'MikeP Paper Towel' sealing method!

STOP IT, PJ! JUST STOP IT!!

 

[Altimat]

Re:Hull Ideas for Nitro .12 Cat

I see! ;D But I already picked up on the paper towel trick! 8)

 

[Propjockey]

Re:Hull Ideas for Nitro .12 Cat

I'm havin' WAAAAAY too much fun today! ;D

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

Hey PJ maybe you need to cut down on your lucky charms intake. I think the sugar is driving you insane

Here is a snapshot at the CAT sponson test mule

I will test this thing out tomorrow morning.

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

Here is another shot of the bottom of the sponsons

 

[Propjockey]

Re:Hull Ideas for Nitro .12 Cat

Very interesting! I'm curious, though...why did you cut it so the surface area of the sponson increases toward the rear?

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

PJ that a good question. I don't have a good answer -because I still have not tested it.

The profile is similar to a cat hull that I bought from Randy Naylor at BBY Racing about a year ago.

My theory is that the triangular running surface will stabilize the rear end and unload the prop. Having smaller running surfaces in the front will help keep the hull from blowing over.

I've run the yellow mule boat quite a bit with the full sponsons. I'll let the water decide if the modifications are a change to the better... Keep them fingers crossed :-

Couldn't find the radio hatch so I'm making a new one.

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

First Build Pic.

This is the center hull section for the Nitro Aggressor 23A

Missing a bunch of wood and it is already quite strong!

 

[_laxmasta2039]

Re:Hull Ideas for Nitro .12 Cat

whoa,

that's really stocky and short...both my cat's are/were alot longer, then again they are designed for elec.

does that have anything to do with tub shape?

looks good though, i'm jealous that your succeeding where i failed!! ;D

Joe

 

[Don Templeton]

Re:Hull Ideas for Nitro .12 Cat

Very interesting theory on those sponsons. Just might work!

 

[Eric Perez]

Re:Hull Ideas for Nitro .12 Cat

It's a lot longer than what it looks :

The center tub is 6 3/8 wide and 18 5/8 long

In comparison with the previous design the center tub on the NA23A is as long as the yellow one in the previous photos.

 

[Hammerhead]

Re:Hull Ideas for Nitro .12 Cat

Hey Eric! I have been thinking about building a .049 rigger. I'm not so sure that I will go with a .049 but something under .10.

I have been looking at this cat. I'm not so familiar with running cats, but it sure looks like an easy build. I might have to put the .049 rigger on the back burner. Still recovering from all the money I spent on the Hammerhead .46, so it might be a few weeks before I get started. Please give some help with the dimensions and so forth when I get ready to start it. I have a REX .21 that is in fair condition. I also have a ton of SE-MX .21 pull starters laying around thanks to everyones lack of interest : . Might want to go with one of those. Hammer