Das Boot - Generic 32" Twin Cat

[FighterCat57]

I decided to build the most generic and least expensive twin cat I could come up with. What I ended up with was a $350 twin cat. The goal is to hit 60mph top speed on 6s and get 15 minutes of run time at 40+ on 3-4s.

It's a simple twin 540 1800kv inrunner setup with twin Turnigy 120's, 4mm stingers, and a gel coat finish white hull.

I think I'm going to paint the hull with bright blue accent lines for a two tone finish with a nice thick shiny clear acrylic lacquer finish.

Photos of the build to follow.

[FighterCat57]

I take that back, I'm not using the Turnigy 120's... I'll be using the generic 125a ESC's from the Genesis and the Apparition. Guess top speed will be on 4s. Not going to push these ESC's.

I'm using a lightweight passive heat sink, 3" by 5" with water tubing for additional cooling. Photos to follow once it's configured. Thermal epoxy will hold both ESC's to the heat sink.

No motor mounted heat sink, the motors with the built in heat sinks tend to do pretty well.

[Simon.O.]

Watching with a great deal of interest as my single 30" Cat may have to go twins if you come up with a nice recipe.

I was thinking along similar lines to you and have looked at the following.
Motor

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5146

ESC Generic 100A Mystery or similar from the bay

http://cgi.ebay.com/RC-Model-100A-Brushless-Speed-Controller-ESC-SL019-/390173411909?cmd=ViewItem&pt=UK_ToysGames_RadioControlled_JN&hash=item5ad825ca45

Props Alloy venom EKOS 36mm props

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXYLA8&P=0

Packs from HK or your local prefered supplier.

This would be solid 3S setup but could be run as a 4S setup for more giggles.

That is what I am thinking for a twin to suit a ~30" cat.

[FighterCat57]

Watching with a great deal of interest as my single 30" Cat may have to go twins if you come up with a nice recipe.

I was thinking along similar lines to you and have looked at the following.
Motor

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5146

ESC Generic 100A Mystery or similar from the bay

http://cgi.ebay.com/RC-Model-100A-Brushless-Speed-Controller-ESC-SL019-/390173411909?cmd=ViewItem&pt=UK_ToysGames_RadioControlled_JN&hash=item5ad825ca45

Props Alloy venom EKOS 36mm props

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXYLA8&P=0

Packs from HK or your local prefered supplier.

This would be solid 3S setup but could be run as a 4S setup for more giggles.

That is what I am thinking for a twin to suit a ~30" cat.

Simon, that motor will run 4s nicely with a small prop, like the 32mm EKOS prop. I have a pair in my other 32" cat doing low-mid 50's on 4s with the 32/3 plastic props.

[Simon.O.]

Simon, that motor will run 4s nicely with a small prop, like the 32mm EKOS prop. I have a pair in my other 32" cat doing low-mid 50's on 4s with the 32/3 plastic props.

I take it you are talking about the stock EKOS props 32/3??
If so then I may just twin the big Cat !!

anyone want a KD540-9xl with carbon jacket, used a few times? PM me if so.

[FighterCat57]

I take it you are talking about the stock EKOS props 32/3??
If so then I may just twin the big Cat !!

anyone want a KD540-9xl with carbon jacket, used a few times? PM me if so.

Yep. Everything I've read about the HXT 36-56 says, 4s, low prop and so far... it's worked!

[Simon.O.]

Yep. Everything I've read about the HXT 36-56 says, 4s, low prop and so far... it's worked!

I agree with small prop and wicked rpm ! Have you tried the 36mm Alloy props (twins) for this size ~30"hull ?

If I am a thread hog then sing out and I'll PM you for more info.

[FighterCat57]

I agree with small prop and wicked rpm ! Have you tried the 36mm Alloy props (twins) for this size ~30"hull ?

If I am a thread hog then sing out and I'll PM you for more info.

No worries, chat away, this is a forum and my threads are certainly not exclusive!

In the KOS, I did try the 36mm props and quickly overheated 120a ESC's and motors on 4s, topping out at 45mph. 3s no heat problems, but not so fast, 38-42mph according to my run logs in various water conditions. When I went to the 32mm props, I noticed very low amp consumption, so switched to the stock 60a ESC's and am very pleased with the setup results. For 4s, I am using 30c 4k packs. For 3s, 30c 5k packs. All wired with a 10 gauge "X" harness to equalize power distribution and help prevent either side from pulling against the other.

Back to Das Boot!
The plan is to run her on 6s for top speed runs and 3s-4s for regular fun runs. According to the HiModel specs on the ESC's they can handle up to 6s but I'm not sure about the continuous amps, so will be quite cautious about increasing amps. I also do not know if there is a safety mode protecting from overheat, so will approach setups with extreme caution and conservativeness, increasing prop size and battery size slowly. Starting config will be 3s with 32mm props.

[Brushless55]

What hull are you going to use?

[FighterCat57]

What hull are you going to use?

An unpainted Apparition hull:

Don't know if I'm going blue or red with it.
I'm leaning towards mostly red on white with black trim. Black is so hard to maintain, shows every little scratch and water spot.

The other option was to leave it a dull white with a decal on the side that said: many fast many happy china boat

[HYDROJERRY]

How about white hull with purple and yellow trible sworlls down the side and across the hood,,O ya im feelin that....

[ray schrauwen]

I would have used Turnigy T500 2200KV motors instead. $20 each & almost Scorpion quality.

The infatuation with water cooling motors seems to lead to burnt parts.

Instead of looking for cooled cheap marine motors, look for inexpensive, very powerful outrunners that don't need coooling. One person mearly dropped in the slightly inferior Typhoon 500 motors, no cooling and he gets 50mph without sweat.

By all means try these motors. Learn....

[ray schrauwen]

The beast!

[Jeff Wohlt]

I plan to try thiose Ray!

[ray schrauwen]

Bring spare undies... :)