MRP FAST CAT

[coxbros1]

Nor sure if this is allowed because its a boat, but its more about the motors anyway. (Delete if not allowed) Scored this off Ebay several months ago in great condition. Reason (1) it was my 1st rc ever along with the Big Bear bought from Tower thru a catalog back in 86' i believe. (2) its got the original and "most classic" bag motors of all time, just ask Citylife. I wanted to run these original motors so i had this vintage Tekin TSC411 ESC layin around, wired the motors in parallel and dropped in one 2200 3s lipo on one side (put weight on other for balance). The esc was rated for 4-11cells so voltage is cool. Did a custom fan mount to blow right on the heatsinks. Torque limiter on esc set to max so not to arc the comms too bad or damage the vintage props.
Motors sound great and look new inside. Thye spin up pretty good on 3s. Havent had a chance to test it on the water yet but will as soon as weather breaks here. I know Thumbs is keen on seeing how these old motors and esc perform. Hope i dont have any issues and lose the damn boat, that would suck.

[THEYTOOKMYTHUMB]

Be sure to wear your speedo and snorkel that day just in case you lose signal! Great to see that old Tekin back in action!

[Coelacanth]

Nice, and don't worry--this is the ideal place to share your boat project. I started my own mod thread here for a FeiLun FT012 boat project I'm working on.

So, do each of those motors power separate props? I wonder how the ESC is able to keep their individual RPMs consistently the same? Even though the motors might be identical, the power bands between each are unlikely to be identical, so I wonder if that means you'd be constantly adjusting the steering left/right to counteract the variation between motor RPMs?

That said, a dual-motor RC boat is really cool!

[coxbros1]

Good point, yes they are dual prop, so we are gonna find out. I remember the one i had back in the 80s going straight tho. Hopefully will try it tommorrow

[Coelacanth]

I was intrigued and did a bit of reading on twin-prop boats...at least with full-size boats, the props typically rotate opposite of each other, so that the torque created by one balances out the other...which you'd notice when steering. If both motors rotated the same direction, it would constantly pull to one side and you'd probably have to adjust the rudder to compensate. Interesting.

https://www.boatdesign.net/threads/twin-propellor-counter-rotation.47954/

That doesn't even look into the issue of 2 motors being nearly impossible to be identical with power output/RPM.

At the end of the day, it probably doesn't even matter with a small RC boat, you're always steering on-the-fly anyway.

Physics always gets me thinking...

[THEYTOOKMYTHUMB]

Get some video!

[coxbros1]

I will, even if its cheesy. I can send it to u and u can upload it via your youtube, scenery will he straight out of a friday the 13th movie!

[THEYTOOKMYTHUMB]

I think part 2 would be the most appropriate please. The video will be judged for historical accuracy. Part IV may also be acceptable.

[coxbros1]

U think anyone else on here even seen a Friday the 13th?
Part l thru Vll only, with the exception of the Killer Cut

[THEYTOOKMYTHUMB]

Probably. Mostly children of the 70s and 80s on here!

[coxbros1]

Boat was ran today, all went well. Footage sent to Thumbs for editing and production. Hopefully he will upload it later today. The boat didnt have any torque steer, it went straight

[Coelacanth]

Thanks for the update, looking forward to the vid!

With modern brushless boats being so light and powerful, even putting in a larger prop that's too much bigger, or adding a LiPo cell or more powerful motor, can cause these boats to barrel-roll in the water instead of accelerate forward, due to the high torque of even single prop boats. A lot of people discovered this while over-modding (heh!) their modern RC boats. The effect is probably also reduced with catamaran-style hulls, which would be more stable.

[coxbros1]

This definately isnt overpowered, lol. Runs decent for bag motors tho. I will apologize in advance for the 5 short vids or so instead of one long cool vid. I have to keep the vid under 30 secs each or i cant send it to Thumbs

[THEYTOOKMYTHUMB]

That thing was actually faster than I thought it would be. The 3s helps I'm sure. I'm having technical issues with my youtube account. I'll keep working on it. I think my daughter changed my password... or I have 2 different accounts. I can't quite tell.

[coxbros1]

But u can fix it? We got people waitn!