Fantasm Conversion Single to Twin

[Tbauer]

Well, after some serious debate, sound advice, and many disappointments with the single set-up, I decided to go TWIN....... All I can say is, DUH!!!!

Actually, kidding aside, the Fantasm is such a great hull that a single motor setup can't push it to the edge like I was trying to do. I don't remember who said it, but it is true that once you go fast, its near impossible to "de-tune" it down. With the single set-up, I was pushing too hard and burning stuff up......... KEITH BRADLEY said hey dummy, go to twins............ Sooooooooo just like any well disciplined military person would do, I followed orders.....j/k But Keith did suggest it and let me tell you for myself, having that comfort that I am not stressing the components as hard and having that reliability was a HUGE BONUS..........

Special thanks to Keith for all the help a SUPER busy go could give. He does more than he should so I appreciate his time. OSE and Kintec their parts and delivery as usual were fast and if any errors occurred they corrected timely. I didnt forget you RUMDOG......Thats for the countless hours of soldering you handed down. Getting rid of the Deans was a Pain in the A$$, but had to be done. So thanks for pointing it out.

I had a single Leopard 1480 kv with a turnigy 180a ESC. I bought a swordfish 200a PRO 4-8s ESC....... It burnt up..... I then bought the Swordfish 300a ESC, the big metal box, It burnt up......... I ran it with the same motor I did with the Turnigy whereas I had no problems. So I bought another 1480 kv and turnigy 180a ESC.............Swordfish replaced the 200a ESC which I am going to try in my Genisis. I have not heard back on the 300 yet.

With twin 1480kv leopards I run each 6s pushing a pair of CNC 448's I believe. Everything is extremely cool so I am jumping up to a pair of 3 blade 850's CNC.......... If anyone has any suggestions and where the heck to get a set of props (right and left) I am all ears..... IMG_20130609_123022.jpgIMG_20130611_002025.jpgIMG_20130611_002036.jpgIMG_20130611_002627.jpgIMG_20130611_002525.jpg I had to repaint and touch up and brace inside, not a very pretty job, but its effective and is working as intended. I am hoping for some nice calm water to get a SAW run soon. I hope to get near 70 with the set up.......... We shall see

[Tbauer]

I forgot to add that I bought 2 swordfish 200a 8s ESC's from KBB, I can't wait to run it on 8, up from the 6 limit with the Turnigy's

[iridebikes247]

With this boat on 6s it will rip 70mph for sure. Paint looks good if you ask me! Anyway for props I feel like 450 2 blade props will suit this boat well. I'm sure its warm in arizona so I would stick with this setup for some time.

[Tbauer]

Thanks for the assist......... I will be splashing her tomorrow, hope to hit that 70 mark........... do you have a favorite place that you buy your everyday runner props from? I use Kintec and OSE for the CNC props, was looking for others that may have a different set of options.........

[larryrose11]

I had a single Leopard 1480 kv with a turnigy 180a ESC. I bought a swordfish 200a PRO 4-8s ESC....... It burnt up..... I then bought the Swordfish 300a ESC, the big metal box, It burnt up......... I ran it with the same motor I did with the Turnigy whereas I had no problems. So I bought another 1480 kv and turnigy 180a ESC.............Swordfish replaced the 200a ESC which I am going to try in my Genisis. I have not heard back on the 300 yet.

I assume that this was run on 6S (T-180 limits) but you never said what prop you were using when things burnt up. Any idea of what the amp draw was? Were batteries hot? Have added capacitor banks?
Also, have you blue printed the hull?
Thanks, I would like to learn from your experience.

[Tbauer]

I wish I could tell you definitively what the problem was, but I really don't know. Keith Bradley actually tried trouble shooting with me, he had some good ideas to explore. I was running the Octura 447/3. I sent both of the ESC'S back to Swordfish the 200a they fixed and had it back in less than 4 weeks. The 300 they split with me....... I ultimately without any real tests to prove, that I had some kind of problem with the Leopard motor. Because on 6s I had no issues. But as soon as I jacked it up to 8s, it burnt up the ESC..... KBB said that the increased volts likely exposed a defect in the Leopard.

So to make a long story longer, KEITH suggested going twins to minimize the stress on single components. However, if you weren't going to go over 6 s, that set up worked flawlessly........ Ran low 50's all day, and in prime conditions I got 61 or 62 on gps.

[Tbauer]

oops, no i did not blue print the hull and did not know what the amp draw was......

[larryrose11]

The only Leopard 1480 KV motor I found was the 4092 Motor. Has anyone run that motor and wind on 8S?
The leopard site is down, else I would have checked the max voltage rating.
Other sites suggest a max voltage of 27V.

http://www.helipal.com/leopard-lbp4092-b-1480kv-3-5d-brushless-motor-for-boat.html?osCsid=5g333djoceqnm7itb7ptid38v3

Fresh off the charger, a 6S is 25.2V, 8S is 33.6V

[Tbauer]

I have run a 1600kv Leopard on 8s without issue which is a 4082 and yes, the 1480kv is 4092.

[Tbauer]

If I didn't mention it, it wasn't that my ESC's EVENTUALLY burnt up, they didn't last AT ALL. There was something wrong with my motor. I have a friend who has run 10s on the 1480 for a saw pass and was fine. He doesn't run it like that when he's just having fun. What are you looking to do?

[larryrose11]

Verrrrry interesting. Keith knows is stuff, that for sure.
It is established that hobby ESC used to do not possess the ability to limit their own current. like larger contemporary vector drives do.
The prop is proportional to current, but speed is inversly proportional. At low speed, high load is where current would normally be the highest.
When then motor speeds up, the back EMF created by the spinning rotor produces a voltage that is opposite to the supply, reducing the current at the high speed, compared to low speed.
IF the motor got hot, it permanently looses some of the magnetism of the rotor, (called the Curie temperature), decreasing the back EMF, which would increase the current for a given speed and load.
A surge event, like trying to get out of the hole with with a 3 blade prop, and a weakened motor, _might_ cause a problem.

Another hypothesis could be that it was not too much current, but too much heat.
When these events happened, before you run did you fill the cooling system with water?

Hmmm... If one does not prime the cooling system, the initial lack of coolant might heat up the motor quicker too, perhaps too hot. Once flow is established, cool it back down.
If there was no data logger, you may not ever know. I remember a on-board video, (camera facing backwards) of a person who didn't prime the system. I was surprised that it took 5 seconds before I even see water moving up the exposed cooling tube from the rudder. I couldn't see the exit in the video, so I don't know how long it took to fill the system.
Power electronics dont have very long time constant for cooling. On the large systems I deal with, 1 second with no coolant is too much.

I have no hobby experience in a scenario like this. Im paranoid about cooling after a small rigger I had caught fire, and building my first cheetah.
My professional experience is with vector drives, among other things.
What am I looking to do? Have fun, stimulate conversation and understanding (often by instigation) and get my cheetah operational before the end of the season.

[iridebikes247]

A swordfish 300 is a very very capable esc. To burn one up on command, the motor hand a problem. Or the flex was binding or something weird. That motor can run a lehner 3040, a guy on here used two of those escs in a 94" mystic. Sounds like the motor cooked after running with the seaking then it started picking off your escs one by one. I could be wrong but swordfish makes pretty good stuff.

[iridebikes247]

http://www.mhz-powerboats.com/Propeller/Metall/

I buy the mhz cnc props, they're hardened. I haven't actually run them but from a visual inspection they appear to be a notch above other cnc'd props.

[Tbauer]

Ya, all that technical jargon gives me a head ache.......LOL I like to have fun and do all the work myself, that way I learn....... Unfortunately, before this blog and conversing with others on it, my learning curve was costly (trial and error) =). ...... Now before I get too far over my head, I tap into the wealth of information on these forums......... Thanks for all the feed back...... I ended up *!***!***!***!** canning the motor, so I guess I will find out if the motor was it......... I didn't get a chance to run it due to wind, I am hoping this PM....