12 years in the designing and noe to the xcat side of things..
What?s wrong with balsa and things?
12 years in the designing and noe to the xcat side of things..
What?s wrong with balsa and things?
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Looking good.
Nothing wrong with balsa Jesse. Some of my favorite boats, I've built with mostly balsa.
See the danger. THEN DO IT ANYWAY!!!
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What's the size Jesse? What's going to power this?
This is a 34in by 16 in, prototype for full p, p lim, twin inboard or outboard.
Since my V2 is so successful (but requires twin power to push the beast) I decided to go lighter and aim at more of an XCat look.
Once I’m happy with the performance, I may make this available as a plywood laser cut kit.
The next step after this proof of concept build, will be having the plans cut on a cnc machine and reinforced with cf plate (along the stringers and inside spray rails, as well as two bulkheads and the transom.
I am still working on a strut/rudder mount, as the transom is currently only 1/2 in tall! It will need to be sturdy to resist the stress of the rudder.
As always, I’m wide open to ideas!
I’ll post pics when I get some more skin on this cat; good thing there is more than one way to do it!
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Your V2 cat ran great.
Yes sir I did, then your sponson harpooning side of my cat.
Are you building this one as single?
Harpooning, well mess with the Kevlar reinforced balsa cat and holes will happen..
This will be single inboard. That was the impetus for building a lighter version.
But you can do twin outboards.. $150 per motor, $75 per esc min... $450, but no strut or rudder..
Got the sides skinned. Slowly slowly catch a monkey.. or something like that.
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Got the bottom and sides dun. Now to start the deck.
I glassed the inside and when dry, added foam. We are tickling 2 pounds at this point..
I cut out the bulkheads and added spruce 1/4 in braces for decking.
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Wahoo, first mock up!
Super reinforced transom.. now for battery trays!
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I’m really looking for feedback.
How would like this too look for you to want to build/buy this cat.
Personally, it is a little wide and flat on top.
So... I have started a V3.1... a little narrower than V3.0 and a less flat deck. I’ll post pics of this new one soon.
Please criticize away, I won’t be offended.
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What is the depth of the tunnel?
1.75 inches.. before ride pads.. so 7in wide by 1.8in with ride pads.
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Updates:
Got skin done, glassed the bottoms, smoothing of the tunnel, and the canopy shaped.
Using heavy glass, there are lots of dimples.. why not fill with bonds glaze? No two part to mix and it cures quickly!
Recon I?ll go lighter glass on the sides and deck to avoid this added step..
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Using 1? insulation board, I samwiched 6 pieces together to get the shape I wanted.
Good ole scroll and band saw.. not to mention the belt sander!
1) design shape you want, send to vinyl cutter
2) cut all six pieces, including opening underneath
3) tape together and cut plan view shape
4) remove outer cut away and spray each piece with contact cement, adhere all together
5) clean up cavity as needed
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Here you see all skin is on. Cross grain 1/8? balsa with heavy glass on the inside, except the rearmost compartment... in case we wants twins..
Hatch is same then with Kevlar outer.
Now she sits on the bored games until the morning. (It?s like Christmas everyday that I do this)!
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So.. as I built this, I was realizing the deck is HUUGE!
So, I went back to the drawing and did some tweaks. Narrowed the sponsons, angled the deck, increased the dead rise a couple degrees.
The shape is SO much sexier!!
Here you can see v3 (current version) and v4 sitting on top and beside each other.
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Got ride pads on and all glassed.. while the bondo and primer are battling for my time, I thought I’d document learnings so far.
The main reason for THIS build is practice.. I’m sure many are rolling their eyes, but with this scratch build project (going on 13 years), the technique has thankfully evolved.
1) balsa is easy to cut and shape, but requires fg or cf. be sure to sand the CA joints as much as possible. Also, if you leave any lumps in the balsa surface, you will pay for it once covered with epoxy/glass. My next build will use ply to avoid problems in this and the next point.
2) fiber glass sucks. It’s messy, often lumpy and hazardous to sand, not to mention itchy. So, if it is to be used, these are FG points:
- the coarseness of the weave is related to epoxy/resin permeability. The coarser the more perm, thus the thicker the epoxy it will absorb and “wet out”. If using tighter weave, and therefore less lumpy, the epoxy needs to be thinned AND the balsa needs to be wetter.. otherwise you get unfixable unattached areas of glass #@%!!
- application of epoxy needs to be as even as possible, otherwise you will have obnoxious irregularities.
- bondo will be a saving grace. There is also a one-part glaze that will fill <1/8in gaps.
3) with any cloth, be careful to not sand into it and make fuzzy spots. These will be ongoing issues. The way I found to help fix this is thicker epoxy. 30 or even 5 min will give thickness to cover up the cloth; this especially good to consider on canopies where you want a high gloss and smooth surface. I was trying to have a cf windscreen.. but .. ya. No.
I’ll add more to this post as I think of them.
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Now she sits in primer gray waiting for painting weather..
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Here is a mock up.. with more graphics, but you get the idea.
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That should look sweet Jesse.
Thanks Coop, I hope so!
Funny, on this mission to the production XCat, I will have built 4 “practice” boats before the final carbon fiber reinforced version, being the fifth!
First one is skeleton, second is the above, including practice paint job. Third is the v4 skeleton on the bench, the fourth is being cut now and will be built with 1/32” and 1/8” ply, while the fifth will have cf reinforced stringers and two key 1/8” cf bulkheads and transom, once I make sure all the dimensions of this next fourth practice bugger are correct.
What a ride... R&D ain’t quick, easy or free! But oh so satisfying when you finally get the shape and performance you are after!!
Last edited by Jesse J; 12-31-2020 at 08:38 PM.
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Man, I'm loving this!! I agree, the V4 looks even better! Nice!
Ok Pete, that was the sign I was waiting for..
this build has been an order of magnitude less work!
Here are a few updates..
This is the fifth cutting! My buddy with the CNC cutter had way too much patience for me with this.
But.. now we have 95% perfection.
Cf plate RULZ!! 1/32” cf plate backing 1/8” balsa and then 1/8” cf in key bulkheads.
Last edited by Jesse J; 02-03-2021 at 06:27 AM. Reason: Stupid question marks!
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Laid Kevlar and sealed with west systems dyed black!
Then filled with pool noodle prepping for skin.
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Wow!!!
Looking great.
Man you've put a lot of work into this build.
See the danger. THEN DO IT ANYWAY!!!
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Paul, coming from one who reimagines “put a lot of work into a build” that is a welcomed observation!!
Yes, most of the work has been in the designing, redesigning and working with my buddy with the 2D cnc mosheen!
I owe huge thanks to Dave!
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So after battling with positioning motor, batts and esc, we decided that we (the designer, builder and driver) weren?t going to be able to get weight far enough back for desired cog adjustability... must change course. Abandon single inboard for this version.. design a modification to remediate the weight distribution limitations, and go with twin out drives.
I found some cool steerable drives and go with a twin set up. These are from MHZ and do not house the motor! Thus not adding all that weight up high and more significantly, not limiting motor selection!
Well, I was so anxious to see the hull shape that I installed all the decking and was unable to even get the motors into the sponsons! Hey Dremel, get your cutting wheel ready.
Decided to make motor bay hatches (and modify the design for the next version) to allow installing motors and stuffing tubes.
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