Thundercat 31 conversion build

[lomdel]

I decided to strip out my Thundercat 31 and convert it to brushless because of the close proximity of houses to the canal where I run it. I'm also tired of the constant tinkering and mess associated with nitro.
I ordered the parts as listed below, but is still waiting for it. As soon as it arrive, I will start a photo supported build thread.

Motor : Feigao 10XL
ESC : Etti 150 amp
Coupler : OSE 5mm to .187
Connectors : 5,5mm OSE gold-plated
... and a few other stuff from OSE.

Batteries : 2x 11,1V 3S 3800mah Zippy lipos from Hobbycity
... I will run them in series (22,2V)

Motor mount : Custom CAD designed stringer mounted 4,5" aluminium machined mounts.

I use Prather props ranging from P215 to P245 in size. I will test and see which runs best.

Hold thumbs that the money invested (approx. $420,00 excluding basic TC31) is worth it and that my choices were the right ones!

[Avanti]

this set up should work well
you might want to make sure the etti can handle 6s
I would also opt for more mah than 3800

Keep us posted

[lomdel]

While still waiting for the stuff, here are a few pics of the TC31 what it looks like, how the nitro engine bay looked like, how the bay look like stripped out (the stringers are 4,5" apart) and a CAD image of the motor-mounts I that is being made. I'm making two mounts to clamp both front and back of the can with the cooling jacket in the middle.

[lomdel]

The custom motor-mounts just arrived at my office. They need to be cleaned up and poilshed a bit and the holes for the bolts to be drilled. You'll notice the front one is flat-bottomed to let the motor lay lower in the hull on the coupler side.

[lomdel]

All my hardware, except the lipo's arrived!! I will post unpacking pics soon, maybe tomorrow. But... Alas, I mis-measured the Feigao can diameter and the clamp-mount holes are therefore 2,5mm too big! Bummer!! Back to the drawing board, and back to the waterjet, etc... I will get it right. I am extremely excited about this build, and can't wait to get this monster-motor in my TC31 hull. The Etti 150 is huuuuuggge!!

[lomdel]

A lot has happened since last post! The new motor-mounts arrived. I drilled and tapped them. You'll see I allowed an area on top with tapped holes for an ESC platform. In one of the pics you'll see the ESC mounted on velcro on an aluminium plate on the motor-mount. The hardest part of fitting the motor-mounts was drilling the holes in the stringers! No drill or angle attachment could fit, so..... I drilled them by hand, turning the bit with my bare hands for all 6 holes through 6mm plywood. Yeah, blisters the following morning, but the mounts are in!!
No connectors are soldered on yet, because I am waiting for another motor from OSE. I had a 10XL but FeCalc indicated that a 13XL would work better and possibly not fry my system. So until that one arrive by the end of the week, I'll hold off with any soldering.
the cooling lines are cut and pre-fitted to the ESC as you can see. To maximise cooling, I split the intake before the ESC and routed it outwards through separate outlets. The motor's line is separate as well, hence two intakes from the rudder and three outlets at the side.
Here are a few pics of how I taped up the 10XL to use it top line-up the motor-mount, the mounts, how I drilled the holes, the installed mounts and where I am now...

[Jimmy Sterling]

Looks great, will be very interesting to see what sort of speed you get out of it

The hardest part of fitting the motor-mounts was drilling the holes in the stringers! No drill or angle attachment could fit, so..... I drilled them by hand, turning the bit with my bare hands for all 6 holes through 6mm plywood. Yeah, blisters the following morning, but the mounts are in!!

Your real commited and the anodised mount look sweet, wish
I had the facilities to anodise stuff

[lomdel]

I will post some more progress reports as soon as my 13XL motor and the 5,5mm bullets arrive. Only then will I be able to mount and connect everything...

[Doby]

Why the switch to the 13XL??

[lomdel]

According to the specs the 540XL series motors can handle max 1000W. With the 10XL FeCalc showed more than 2000W to the motor with my 6S set-up. That would have fried the motor! With the 13XL I will be able to keep it around 1200W for short runs at a time. I should have actually gone with a 5S set-up and a higher kv rating, but this project's cost has already gone through the roof, so I'll stick with the 2x 3S packs and use the 13XL to be safe...

[lomdel]

I have since removed the radio box to clean up the interior and made a snug-fitting sub-hatch that'll be taped up. All the holes in the canopy have been plugged with either grommets or blackened lexan pieces. The exhaust outlet have been plugged with a grommet as well. The hull is now as watertight as I can make it...

[txboatpilot]

Changing to the 13xl is a great choice! You and your esc will be very happy you did... Sounds close to a set-up I use, and it has worked great for med. sized boats.. I have ran the 12xl and 6s with different esc's and never had any heat problems..

You shoul have lot's of fun with this cat... Cait wait to see a little video..

[Doby]

According to the specs the 540XL series motors can handle max 1000W. With the 10XL FeCalc showed more than 2000W to the motor with my 6S set-up. That would have fried the motor! With the 13XL I will be able to keep it around 1200W for short runs at a time. I should have actually gone with a 5S set-up and a higher kv rating, but this project's cost has already gone through the roof, so I'll stick with the 2x 3S packs and use the 13XL to be safe...

Ahh ,,forgot you were running on 6S

[lomdel]

I'm leaving on holiday tomorrow and my 13XL motor and 5,5mm bullets haven't arrived yet! Now I'll have to postpone finishing the build, which is extremely unfortunate because I'll have to stare blankly at the empty canal in front of our holiday home (see pic). I arranged for my local PO to forward the package though.
This is just to show you where I intend to run it, not showing off...

[Steven Vaccaro]

I'm sorry to hear that the motor didnt show up in time.