MADD CATT -41" fantasim saw build

[Cooper]

Ahhh yes, the first one I had I did that, a little too much and snap! Had to replace and got some thermal epoxy to attach new tube. That aluminum is pretty pliable and for the most part they are a little stingy with the thermal epoxy. If you ever have to reattach or reinstall tubes you will see they don't fully bed the tubing. I don't think it's a concern to pull new and inspect but it is a crucial part of the heat exchange. If I ever got bored I would replace them with copper and have two slight bends extending the tubes a bit, make it look all pretty and such :). But what you suggest will work good and way simpler:).

[Cooper]

Ok I'm back in the swing of things, the last water pickups were just a bit too big and I just wasn't satisfied with how they turned out, I'm still learning in the machining department. These are alot better and more uniform. The whole cooling system will have the largest diameter at the intakes. This will allow more water flow by means of higher pressure. Verses having the smallest diameter at the intake. I should also have a better chance of seeing the water shooting out, kinda like a garden hose having the nozzle at the end pressurizes the flow. It's just for my own reasons not for any theoretical advantage. More water IS always better for heat exchange (cooling) bottom line period! But in this boat as it is going to be hitting triple digits it is my opinion it is better this way. Alot of thought into the intakes, too big and they could disrupt water heading towards the prop. Too small and not effective. So by my red-neck science these are the right size. :).


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[Cooper]

I just couldn't resist bending some tubing. I'm going to use these so I can hug the hull with the lines until they get up to a more user friendly area, somewhere around the front of the servo. They are just set in place for now, they will be lower as I want to make sure I will be able to get to all the necessary hardware. (motor mound bolts and stinger mounting bolts.) I finally made my own round head allen screwdrivers, smaller so I can get to the bolts alot easier.
So now comes the sad part of cutting holes in the bottom of the hull!!


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[iridebikes247]

Ah yes I remember this step and how apprehensive I was beforehand but, boat needs cooling! Good luck cutting through the bottom of the hull. I really did a hack job when cutting out the bottom of my hull but a bit of epoxy + sandable filler and it looked like it came that way. Nice job adding the brass tubing for cooling.

[Cooper]

Well here's tonight's parting work. I will have to remove some material from inside the hull or remove some more aluminum from around the intake. I don't want to remove much from inside the hull so I'm going to try and match the intake, so a little more work. It doesn't have to be perfect just has to sit flush with hull bottom. As inevitable I will have to epoxy any gap between hull and intake. On the inside epoxy and a little bit of cf to cover and keep it in place. Brass will get epoxied in.


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[justski]

the tubing is going to look sweet ...i did that to mine

I just couldn't resist bending some tubing. I'm going to use these so I can hug the hull with the lines until they get up to a more user friendly area, somewhere around the front of the servo. They are just set in place for now, they will be lower as I want to make sure I will be able to get to all the necessary hardware. (motor mound bolts and stinger mounting bolts.) I finally made my own round head allen screwdrivers, smaller so I can get to the bolts alot easier.
So now comes the sad part of cutting holes in the bottom of the hull!!


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[srislash]

Looks good bud.I like the tubing.CLEAN

[twissted]

Light weight brace

And a motor mount support. This will get thinned down as much as possible to save weight. Possibly be a location for hatch bolts also. It's been slow work on this as I have a funeral to go to tomorrow. But getting back into the swing so more to come soon.


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I used carbon to do this. I also drilled holes for the tubing to get a clean look. It also made the bottom of the hull stiff and strong at the same time.

Just another way to skin a cat!

[Cooper]

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[Cooper]

The two intake holes cut out and a pic of a trial fit. ( lots of measuring and gentle filing )


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[twissted]

This is a very clean look that you have going. I seems that your adding a lot of weight though.

[Cooper]

I had the hull clamped to a table to press the pick-ups during epoxy setup, but I didn't take any pics of that- forgot to. I just used some 30 min. Epoxy with milled fglass. The tape and strip of carbon is to keep the pickups flush with bottom, so hopefully I woulnt have to be sanding any aluminum.

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[Cooper]

This is a very clean look that you have going. I seems that your adding a lot of weight though.

Yea, weight is always a concern. The brass tubes are going to be a lot shorter, I just didn't cut them. And weight wise- vs strength, tubing isn't really much more, especially if using thick walled silicon tube. The weight really adds up when people use excessive epoxy and resin- it doesn't add strength just weight. And the cooling system is a necessary evil in the weight department. And,,,,, if it weighs a bit more then so be it, I just want it to stay together after a few 100mph flights. In my opinion you can't have enough reinforcing. Remember this isn't a sport build, some strip things down to keep weight at a minimum and some reinforce to be able to run more than once. And with two neu 1527 1y motors I don't think weight of this will interfere with performance much. (yes the more reinforced the more weight and it is a balancing act). And I want all the cooling lines to be short and secured from thrashing around to help eliminate accidental detaching.
Always have to remember "speed kills , how long you want to live?" kinda like that quote and want the MADD Catt to live nine lives :)


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[Cooper]

And the bottom of the pickup. I smeared a little dirt on the area so you can see the epoxy spread a little better. This is pretty even coating on hull and pick up so a little sanding and integrity of hull lines should be kept. I smeared some grease in the pickups so epoxy didn't stick. These turned out pretty good I'm not going to have "bondo" any areas just sand.
( I don't use bondo, i do use a two part marine epoxy paste for filler in gap areas)


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[twissted]

I get it's how you bond with epoxy that makes a hull strong. I have stoped using hobbie apoxy and started using 3000 psi epoxy. I don't think that the cost differance is much and I like the added strength. I also like the stronger epoxy, as it is easer to find.