Simons Bigger Cat.

[ozzie-crawl]

looking good simon, if your running a mystery 200amp esc i would just solder another set of power wires to the top board if wanting 2p

[crabstick]

+1 on the Video please

[Simon.O.]

Well I ran it.
It goes like a scalded cat in a straight line until it wobbles a bit and then hooks and rolls over.
It has a shocking hook on the turn and will roll outwards and onto its lid.
It is 99% watertight and I'll have to sort that too.

The bottom like I said is a blank canvas and now it is time to cut and paste.
I'll go with flat ride pads on the front ones and raise up the rear ones a little.
This is going to be a long and interesting journey.

[crabstick]

I suspected as much with so much dihedral, but hey, its all fun finding out what works and what doesn't!

[Simon.O.]

It now has 1" wide flats on the bottom
It is still a 6 point hull in that all of the step rears touch the table.
I'll give this a whirl and then look at new ideas tomorrow.
Pics of this afternoons cut and paste work.

[crabstick]

looks a lot closer to the sprintcat style sponsons now, minus the strakes and spray rail.

should turn I reckon.

[Simon.O.]

looks a lot closer to the sprintcat style sponsons now, minus the strakes and spray rail.

should turn I reckon.

Fark turning !! All I want is wicked straight line speed
I'll be happy if it behaves in the morning.
There is still an agressive 3-4 deg AoA on the rear and middle ride area. This can be reduced if needed and will end up a bit like my smaller Cat. By the time I do a mini cat I should have all of this sorted.

If the weather is right in the morning I will run this on 1P as the other very good pack from Andy will be going in the big rigger for some nuts out speed runs. My less than spectacular 4S pack will ride as ballast in the Cat.

I'll be back after lunch tomorrow with more info.

[Simon.O.]

I ran it with the new bottom profile, better but not perfect.
It still porpoises a little before it gets up to speed and then the nose digs in again and it will plough a little. I believe this is caused by too much lift in the rear from the aggressive AoA of the rear steps. A little positive on the strut tamed it a bit.
I got some good wot runs that were a bit of a handfull. I even hit a small polystyrene flaot that the sail guys use and you can imagine what a 3 bladed prop doing 30 grand and two stainless rudders at 40 odd mph will do to it. A small burst of white snow and the float had a new hairdo.

I will now build out the AoA on the rear pads in much the same way as i did with the smaller cat and see how it goes next week.

[norbique]

looking forward to the pad mod.

[crabstick]

Simon, before you do that, I have one small suggestion, Extend the tunnel traps right to the back like.. might trap the air you need to settle the rear and settle the front down. its a very easy mod to test too

[NitroVal]

Dude, that boat turned out awesome. I wish I could find the time or the motivation to finish my balsa cat.. I got all the paper templates cut, just gotta cut the wood.. Ho hum....
We need videos!!

[Simon.O.]

Simon, before you do that, I have one small suggestion, Extend the tunnel traps right to the back like.. might trap the air you need to settle the rear and settle the front down. its a very easy mod to test too

Matt you have a very valid point there and it is something I completely missed. Tunnel traps. They are there on my smaller one and were meant to be there on this one. I'll give them a go and see what happens.

I still believe there is too much AoA and too little ride area on the rear pads but I'll give your suggestion an honest run first. It is very quick and easy to do too.

I have discovered that I can easily run this on 4S1P untill I get the handling sorted. It does not need 2P while it goes nuts at speed. The second (tired) pack is just ballast for now.

It will be Friday at least until I can get on the water.

[Jesse J]

Hey Simon,
here are the radical ride pads I was talking about. I just threw these on there and had intentions of sanding them down... I think they work just fine.

The tunnel height is 3/4"
tunnel width: 3 1/4"
Hull width: 7 1/2"
ride pad outer height: 3/8"
step depth: 5/16"
ride pad length: 15.5"
ride pad width: 1 1/4"
tip to transom hull length: 22.5"
If I remember correctly, that was 1" balsa. I will check again when I get home and edit the measurements.

[Jesse J]

the rest.

[Simon.O.]

I have filled in a bit of the wedge area in the steps to give a flatter ride area. This went well.
With a 440/3 set 10mm or 3/8" above the sponson line it got up and went. There was a bit of propoising and then ploughing at the front.
On with a X637 and things looked better
On with a modded 640 and it all began to shape up well.
The porpoising was much less and the nose began to rise for a tail ride that I like with the Cats.

I have now filled in more of the wedge and it sits on 30mm 1-7/16 wide rails with small vents at the rear of each ride surface.
I'll get out on Sunday morning and give the new ride rails a run.