Scotts E-thundercat build

[forescott]

Hi all, I have been thinking about doing brushless proboat thundercat build for a while. I like the look of the hull, and I wanted a hull big enough to possibly hit 50mph. Also this is my first build, so I wanted someyhing relatively easy as the t-cat already has useable hardware. So I finally got enough money together to get the parts I need. Found a used boat from hobb-e-mart. Bought a new castle 1515 1Y. OSE water jacket. Turnigy 180 on the way, and a few other parts. I am kinda stuck as to whether I should leave the wood stringers and use a "between the rails" motor mount, or remove most of the wood stringers and moun the motor directly to the bottom of the hull. I actually bought both mounts. But the one pictured seems kinda small and am afraid it is a little to weak to handle the torque of the castle motor. Any thoughts or ideas??

[forescott]

I have also had a little time to work on sealing up the holes on the hatch. I found some thin plastic at home depot and cut some pieces to fit over the two intake holes, the two small outlet holes, as well as the radio antenna hole on the top of the hatch. I used epoxy made for plastic to bond the pieces to the hatch from underneath, and also reinforced the tabs that hold the front part of the hatch in place. The hatch is thin plastic and pretty flimsy. I don't know how it will hold up in a crash, but I think i'm gonna just tape it up as best as I can for now.

[Steven Vaccaro]

The mount is plenty strong for the motor. But the hull bottom may not be thick enough for it. Rail mounts do a good job at distributing the weight of the heavy motors over a larger area.

[lomdel]

Good luck with the build! I did a conversion a while ago as well : http://forums.offshoreelectrics.com/...ead.php?t=5727 . A few suggestions based on what you already did :

Closing up all the hatch holes will increase drag. The air will now have to move OVER and not straight THROUGH the canopy. I cut a piece of perspex/lexan as a sub-hatch and tape that down. Nice and clean seal all around. You'll have to remove the two plastic clips and CA glue down some magnets or something to hold the front down. I then cut some extra holes in the back of the canopy to optimize air flow through the canopy.

Using stringer mounted motor-mount will stabilize the hull structure and be more rigid than a bottom mount one. It will also leave the option open to re-convert it back to Nitro should you ever be so desperate... Where did you "buy" a stringer mount that would fit between the TC31's stringers? I had to design and CNC machine one...

Upgrade the stock rudder servo!

What props and Lipos are you going to start with?

[lomdel]

You can also remove the radio box now that the inside of the entire hull is sealed. Just remount the plywood servo plate to hold the servo, Rx and Rx pack.

[forescott]

Well, I decided to remove the wood stringers from the hull. No going back now! And bought a piece of 4-ply hobby grade plywood that I was thinking of epoxying to the hull for strength. The only problem is the 3/16 plywood raises the motor and mount, causing me to have to move the motor forward in order to line up the flex cable. My question is, is it o.k. to have 1-1/4 inch of exposed flex cable that is not supported by a stuffing tube?? You will notice a rectangular cut-out in the plywood. I did that so the motor mount would sit flush on the plywood base.(The pictured motor mount is not tall enough for the castle motor and cooling can. I have a couple of other mounts on the way which hopefully will work better. The last picture shows how much better the motor lines up with the flex cable when seated on the hull without the base. Which brings me to my next question, Can I apply a few layers of fiberglass cloth and resin to strengthen the hull without as much buildup as a piece of plywood. And will it be strong enough??

[forescott]

Good luck with the build! I did a conversion a while ago as well : http://forums.offshoreelectrics.com/...ead.php?t=5727 . A few suggestions based on what you already did :

Closing up all the hatch holes will increase drag. The air will now have to move OVER and not straight THROUGH the canopy. I cut a piece of perspex/lexan as a sub-hatch and tape that down. Nice and clean seal all around. You'll have to remove the two plastic clips and CA glue down some magnets or something to hold the front down. I then cut some extra holes in the back of the canopy to optimize air flow through the canopy.

Using stringer mounted motor-mount will stabilize the hull structure and be more rigid than a bottom mount one. It will also leave the option open to re-convert it back to Nitro should you ever be so desperate... Where did you "buy" a stringer mount that would fit between the TC31's stringers? I had to design and CNC machine one...

Upgrade the stock rudder servo!

What props and Lipos are you going to start with?

I have read your thread several times. southriverrcboats.com is where I ordered a 4-inch bween the rails mount. I was planning to somehow shim each side 1/4 inch to accomodate the 4 1/2 inch spacing on the TC. Is the stock servo too weak?? I was thinking of getting a traxxas waterproof servo.(not sure what the torque is though) Thanks for your input!!

[Steven Vaccaro]

I would suggest extending the stuffing tube. You will need a piece of the same size brass as the stuffing tube and a small piece of the next size up. Its easy, cut out some of the glue around the stuffing tube. Cut the smaller piece about 1" to get it closer to the coupler. then slide over a 1/2" piece of the larger stuff. Let a 1/4" ride on the old and new stuffing tube. It acts as the brace.

[Steven Vaccaro]

I would suggest extending the stuffing tube. You will need a piece of the same size brass as the stuffing tube and a small piece of the next size up. Its easy, cut out some of the glue around the stuffing tube. Cut the smaller piece about 1" to get it closer to the coupler. then slide over a 1/2" piece of the larger stuff. Let a 1/4" ride on the old and new stuffing tube. It acts as the brace.

[forescott]

I got my new motor mount today from phil @ vac-u-boat. I had to do a little trimming @ the back to make room for the cooling can, but I like the mount! I decided to use the 3/16 plywood to strengthen the hull. Like my redneck clamp? A piece of 4x6 and 40lbs. of paving stones! I also ordered a few decals. Not sure if I want to use the punisher ones or the old school thundercat cartoon logo.

[Eodman]

Here's my Thunder Cat -----

[lomdel]

I got my new motor mount today from phil @ vac-u-boat. I had to do a little trimming @ the back to make room for the cooling can, but I like the mount! I decided to use the 3/16 plywood to strengthen the hull. Like my redneck clamp? A piece of 4x6 and 40lbs. of paving stones! I also ordered a few decals. Not sure if I want to use the punisher ones or the old school thundercat cartoon logo.

Glad to see you got rid of the radio box! Will this motor and -mount setup allow you to use a sub-hatch or are you going to stick with the waterproofed main canopy?

[forescott]

Glad to see you got rid of the radio box! Will this motor and -mount setup allow you to use a sub-hatch or are you going to stick with the waterproofed main canopy?

I,m gonna give it a try with the sealed canopy. I also bought a traxxas high torque waterproof servo to replace the stock one, and have a 2.4ghz radio on the way.

[forescott]

Finially got a chance to work on the thundercat today. Was able to extend the stuffing tube 1 1/2" with a larger piece of brass tubing to act as a sleeve over the original tube and the extension.(thanks steven!) Got a new longer teflon liner and cut down the 18" flex shaft to fit. Also added some fiberglass cloth and epoxy to wrap around the stuffing tube for extra support. It feels pretty solid now. Just waiting for my turnigy 180 to get here so I can lay out the electronics!

[dddmx3]

isnt 18" too long

and is the teflon line the white stuff inside the stuffing tube?