Twin Cat Strut assembly on a budget -> help please ;)

[G Doggett]

If you can settle for a top speed of 'only' 90 kph why don't you use the set up I have in my twin Jolly.
2 Ammo 2300 motors at $67,99 each, and 2 X-Power 100 ESCs at 74.99 each, all from OSE.
I power this with 2 4S 5000mah lipos and the average current draw is 50 - 60 amps per motor.
I have scratch built my own drives from stainless steel tubing, but you could maybe use a pair of SuperVee units.
Graham.

[astecme]

Norbique, what about using 4mm or 3/16" stinger units - e.g. HOR/TFL or ETTI (4mm only).

Allan

[norbique]

I was thinking of the Turnigy's. Either the 80A plush ($55) or the 100A ($65). I'd modify them and add water cooling as the first step, then some extra capacitors. And try to prop it so to stay within the limits of the ESC. FECalc shows results around 70A.

[Flying Scotsman]

Ok, so two motors each on 6S power and what ESC's? This is getting expensive

Douggie

[norbique]

Hey Douggie!

Thanks for the reply!
My biggest problem is I want the cat to look more or less scale... That said I am thinking in a twin setup. This is the problem. I'm aware of the fact that twins cost roughly twice as much a single drive setup does. Still I want to make a twin cat, (never had one before).
I was searching the Internet for various motors, ESC, and since I can't afford a NEU a Plett, or a Lehner, I gotta stick with the "low-end" chinese motors. I was thinking of the KB-45L perhaps the 10 turn version which is 1800KV, and power it with a 6S Lipo.
I have a small 3S A123 pack that I built and use it in my Hydromite and I love it. So at the beginning I was thinking of getting A123 cells for the big cat as well, but my maths quickly showed me I'd need roughly $500 for the 2x 8S2P A123's. Which is a LOT of money. So I think I'll have to stay with thecheaper "fiery" Lipos.

I downloaded the FE calc, and the modded database, plus added my own stuff. I'm playing with it, but it has no feature for a twin setup.
There are other motor alternatives as well, the Feigao 580XL8 or there are the beautiful 6pole 2240 Tenshock motors @ €150each.

My goal was to reach 100km/h, but I would settle with anything above 80. Run time is not really important.

FEcalc shows me around 1500W input needed for that speed, don't really know what a twin setup should say power wise.

Norbert

[Flying Scotsman]

First off cudos to your scratch build cat with a stepped design. If you are short of cash, I would suggest a single drive, what motors, power, speed and run time are you considering?

Douggie

[norbique]

Just a picture of the cat.

[norbique]

I'm building a 1.1m cat from scratch and as I progressed, I reached the building phase where I need to have the strut assembly to make certain mods in the inside of the hull and so on.

I was looking for struts of many kinds, (on ebay, on swissmodelpowerboatteam, etti, hydroandmarine, astecmodels, etc, etc) and I'm still on the same opinion, I can't afford to pay €150 for a set of Arneson Drives. I can't, so I have to start thinking about how to make these drives on my own. I can use the lathe and the milling machine in the local club. Although I don't have too much experience with the mill, I think I can master the knowledge to produce a strut. If nothing else, this project will help me become more experienced.

I'd like to ask those who had done this before, to help me with their knowledge.
Some technical drawings would be nice too. :) Just to help me understand how these drives really work and look like from the inside. Do they have bushings on the prop side and bearing on the flex side? How is the whole thing sealed at the hull, yet still possible to move up and down? All your thoughts are welcome.

Thank you!
Norbert