BlackJack 29 Twin Cat Custom Build

[lakeella]

I picked up this RTR package at the hobbyshop the day they were released. It never touched the water before being gutted for twins. Here's some pics.
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The cardboard cut outs are my templates for carbon fiber pieces
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Here i've cut out teh exsting stuffing box
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[lakeella]

The stingers will be made of carbon fiber tubing with brass lining and a brass strut bushing.
Here i've lined the sidewalls and transom with Carbon/kevlar cloth.
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[lakeella]

This shows how the motor mounts will sit and be glass in place. The cardboard patterns were traced to some scrap plywood so I can mount the motors and get a good feel for were they will be positioned in the hull. I had to adjust the mounting holes so that the motor shaft would line up with the stingers. I also want the motors to sit as low as possible in the hull. the motors I used are just for mockup so I made sure my mounting holes were drilled so I have some leeway on what size motor I can use. I left plenty of room to fit a pair of 40 series if need be.
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[lakeella]

I just finished laying up the CF inlay. I ran it up as far as possible under the front deck. I have one last layup to do and I'll be ready for hardware installation.
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These hulls have a tendency to split along the seams in the front. The sides have the inlay but the center bow at the tunnel only has the factory seam.. So what I do is take some left over cf fabric and chop it into very small fibers. Then I mix up some 30min epoxy and mix the fiber in creating an epoxy/carbonfiber kitty hair type resin. Then simply apply it generously right at the front seam at the tunnel.

[lakeella]

Here's the front seam reinforcing
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[jpf091959]

Excellent, I have a lot on interest in a twin setup. Keep the pictures coming,

thanks

[1611odalys]

Any updates?

[lakeella]

I checked the potential COG with all the parts I have at thispoint and it came out around 28.5% So I should be pretty good. I'll have plenty of room to adjust the batts to fine tune.

[lakeella]

My Cf parts arrived today, started building my stingers today. I have send off the CF parts to be milled. Here's what I have so far.


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[lakeella]

I got some work done on the stingers and motor mounts. I have the CF stinger epoxied in place now just need to mount the stinger brace. Then I can CF the motor mount in place. I am using a 4082 for my mock up and alignment so I'll be able to mount a 40 series if need be. The stinger is set at 0 degrees toe and trim

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[lakeella]

just finished up the stinger supports.

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[1611odalys]

love all that cf on it is looking awesome. Were you got does cf parts from?

[lakeella]

The parts I designed on CAD and cut them from 4mm double gloss CF plate.

[lakeella]

I have made some more progress here's the pics

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[lakeella]

I designed the stingers so that the stuffing tubes can be removed with ease.
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[bigbluechevy454]

Are u one of the guys that run lake ella on sundays?

[lakeella]

Are u one of the guys that run lake ella on sundays?

Yes this is Travis

[bigbluechevy454]

Your the guy from the hobbie store that invited me to lake ella

[lakeella]

yes, that was me. You should come by and check it out. We're there on sundays

[bigbluechevy454]

Sounds good man id like to get a r/c boat. R/c boat with twin outboards

[lakeella]

Sounds good man id like to get a r/c boat. R/c boat with twin outboards

We can do that. I just built an OPC Tunnel that I will be testing out Sunday. Come by and check it out. What type of hull do you want Deep Vee, Cat?

[pyro]

I'm planning on getting one of these for this season. Looks like a nice setup.

Nicd craftsmanship on your twin setup.

[lakeella]

I'm planning on getting one of these for this season. Looks like a nice setup.

Nicd craftsmanship on your twin setup.


I'll be posting this one for sale once I finish it. I'm a builder not a racer. I only run my boats enough to work out any bugs and test for the best prop and misc setup adjustments.

[pyro]

Awesome build.

What have you found to be the best center of gravity point for this hull in stock configuration? I only have 2S lipo's. I noticed that I can add a third pack up front for 6S and still achieve the same COG if I move the side packs backward an inch of two. Does this sound like a good idea?

I was going to start out with the COG at the motor mount plate, around 19" back from the tips of the bow. Is this a good starting point?

[lakeella]

Awesome build.

What have you found to be the best center of gravity point for this hull in stock configuration? I only have 2S lipo's. I noticed that I can add a third pack up front for 6S and still achieve the same COG if I move the side packs backward an inch of two. Does this sound like a good idea?

I was going to start out with the COG at the motor mount plate, around 19" back from the tips of the bow. Is this a good starting point?

Your center of gravity should be between 25-33% from the transom of the sponsons. If you plan to run 6S you need to run two 3S batteries in series, change out the connectors on the batteries, ESC and motor to 5.5mm gold bullet plugs and get a sharpened and balanced 42mm-45mm prop. Other wise you will burn up the ESC/Motor. I've seen it happen too many times. the stock deans plugs and the stock 4mm bullets will get so hot that the wires will melt out of the ESC,and/or the shrink wrap will melt and short everything out. It doesn't cost much to do these upgrades. The connectors are $1.50 each you need 6 each. The S&B prop will cost about $35-$40. I have a wide variety of S&B props. Feel free to contact me if you have any questions

Travis

[pyro]

Thanks for the tips.

I use 50c 2s hardpack lipos in my Slash, so I soldered banana connectors directly to the ESC leads with 90° bend at the joint ends for clearance, with a separate banana series jumper.

If I understand correctly, "33% COG" as you suggested means that the ideal COG is 33% of the sponson's length between the aft running surface and the bow? (near the motor mount plate) Correct?
It appears that this ideal COG value can still be achieved with two packs pushed back a bit and a third 2s pack sideways in front of the motor for 6s power.

A few people have recommended upgrading to an Octura X642 for 4s running. Any thoughts?

I already began to blueprint and sharpen a spare stock prop. I ordered a balancer yesterday to finish the job. I took what I know about 1:1 cleaver prop design and applied to this prop in scale. The nick in the leading edge is probably due to a casting flaw, as my bone-stock prop has the same nick in the same place.

This prop is presently 8 grams, but it's still a work in progress.

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/B1B81DD0-6983-4E12-86A9-6B63328100FD-281-000000C42F7E8DFD.jpg

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/5F154B3D-6FF2-4994-82AE-86BB08B23E73-281-000000C41C55B6AF.jpg