Thundercat 31 conversion build

[lomdel]

How much does this boat wall all-up and ready to go?? All that plywood looks HEAVY... Just curious...

All up with electrics (4x 3S lipos), hardware and canopy weighed in at 2,8kg. I don't have anything to compare to, so don't know if its bad or good...

[lomdel]

This project recently came to a thundering halt due to the disappearing of a OSE package with a lot of stuff that Steven sent me, including a replaced 13XL motor! Steven has already started a USPS enquiry into the missing parcel, thanx for that Steven!
The ESC has been watercooled and -proofed, the set-up done, but no motor yet... A online purchase of a bunch of XL motors from some shady site (4 unused motors for $99,00) also panned out to have been a scam .
I've been looking into the twin catamaran theme and researching it a bit. No decision yet...
If this package doesn't surface, then I'll take all my FE rigging out of the TC31 hull and reconvert it back to nitro I'll then wait for funds to be replenished and start a twin 32" cat project.
Have you guys seen the RCMK catamaran? www.toughracing.com Beautifull!!

[brad65]

Wow I just read all the post, damn I wanted to start my brushless thundercat also, Humm I'm not sure after reading this as to what I'd want with what batterys I have.

[lomdel]

I don't know what batteries you have but consider the following: A Feigao 580L motor on 6S Lipos though a 180A+ ESC or a Feigao 540 13XL on 6S Lipos through the same ESC. Use FeCalc to determine props, but start at X440 or Y537/3 then work your way up. You can use a 8XL on 4S or a 10XL on 5S, but the TC31 is a heavy hull and need some torque to get it flying.
PM ReddyWatts here on the OSE forums to help with choice of electronics for single drive cats...
I have all my replacement parts reinstalled and my cat is ready to fly once more. Will go out this weekend and report back...

[brad65]

Damn dude looks like you've been through hell with this setup. Shame it didn't go better. I hate the nitro head aches but I love the sound. But there are some people hitting 40 with the stock gas motor, different prop and some minor mods. Hopefully you can get some runs on here with some videos I don't think there is a video that I know of with a converted tc31. Looking forward to hearing go news from ya.

Wonder how the mamba monster with the 580l would work? http://cgi.ebay.com/Mamba-Monster-ES...QQcmdZViewItem

[bustitup]

I have never seen anyone "mix" lipo's before.....i was under the impression any batts that wear in parallel or in series had to be the exact same brand and specs?

I think I'll first prop down to X442 and work up from there since I will be runing 6S2P... In one of the pics you can see my 2x2 battery placement as well as the parallel connectors I made

Meanwhile, I watercooled the Himodel 200A ESC with water tubes AND a small 3Racing fan connected to a spare channel on the Rx. See pics.
I am waiting for my can of CorrosionX to waterproof the whole thing. I want to leave the ESC unwrapped to aid airflow and keep it cool. It will be installed raised from the hull floor. I also replaced the 12AWG black/red battery wires with 10AWG. Now only to find the right way to keep the heatsink on the FET's. Maybe zip-ties or four small bolts in the corners...

[Blackjack-sven]

On the picture where you have the ESC mounted with bolts to the motor mount. How did you actually mount it, as I can not see the bolts at all? Did you place the ESC on a plate and then bolt from the bottom?

[lomdel]

Bustitup, As long as the two sides that you parallel are the same you can serie almost anything. For example: Serie 2S+3S=5S. Then Parallel 2x5S=5S2P. You'll see the two sides consist of the same confuguration. All the packs are Zippy 3S 4000mah but the silver packs are 20C and the blue packs are 25C. This is how I understand it to work, could be wrong though...

Blackjack, The ESC is velcro'ed onto a aluminium plate that is bolted to the motor-mount with countersunk (that's why you don't see them) machine screws from the top and screwed into the top of the motor-mount taking care to not let them touch the can at all.
With the new ESC I did not use this plate as the ESC would sit too high and the sub-hatch would not go on flush then. I will post pics of the sub-hatch and the completed set-up today...

[lomdel]

The latest pics...

[brad65]

I noticed you run with your strut up high is that because you have a large prop? And by the way that looks great can't wait to see a video.

[bustitup]

Bustitup, As long as the two sides that you parallel are the same you can serie almost anything. For example: Serie 2S+3S=5S. Then Parallel 2x5S=5S2P. You'll see the two sides consist of the same confuguration. All the packs are Zippy 3S 4000mah but the silver packs are 20C and the blue packs are 25C. This is how I understand it to work, could be wrong though...

Blackjack, The ESC is velcro'ed onto a aluminium plate that is bolted to the motor-mount with countersunk (that's why you don't see them) machine screws from the top and screwed into the top of the motor-mount taking care to not let them touch the can at all.
With the new ESC I did not use this plate as the ESC would sit too high and the sub-hatch would not go on flush then. I will post pics of the sub-hatch and the completed set-up today...

Have you run these batts this way yet?

I'm sorry but I think you are wrong about mixing lipos in series or parallel....I would do some more research

[Blackjack-sven]

In series you double the voltage, while in parallel it doubles the MAH. If ALL your packs are 3s then you can't get a 5s setup as 3+3=6. I would really watch out with the 20c and 25c batts in any formation as the max load can only be 20c or whatever the 20c batts peak is. If for some reason you use more than the 20c peak values you'll blow those before the 25c's.
My 2 cents

[lomdel]

Blackjack, I only used the 5S as an example to show that a 5S can be achieved by connecting a 2S and 3S in serie. I know what configuration doubles what, but thanx to you I now know that I can't combine 20C and 25C packs... You'll see in the last photos posted I plan to run only the two 3S 25C packs in serie to give 22,2V to the ESC. I thus have two 3S 4000mah 20C Zippys up for sale!
Brad, the strut height have been achieved through trial and error testing. It will probably change now since I am going to start testing anew with a X440 prop first.

[Blackjack-sven]

I thus have two 3S 4000mah 20C Zippys up for sale!

How much are you asking for them? I could use another set of batts for my BJ26.

[lomdel]

I just had two decent runs (no GPS alas) out of one set of batts and still they read 3,74V/cell afterwards. First 3min run was with a X440 prop and motor was 95F, ESC 88F. Second run was with a S215 and motor was 115F, ESC was 95F. The speed was visually awesome! The boat drew a crowd at the loch and some guy took a video, promised he'll mail it to me...
Now I can prop up some more. The Himodel 200A ESC worked great and provided smooth acceleration, not stepped like the previous Etti. My watercooling system also flowed consistent and spewed a steady trickle water at speed.
I am officially impressed!