U-3 1/8 scale Hydroplane.

[785boats]

Got a bit done in the last few days.
I made some paper templates for the sponson deck skins, transferred them to the ply & cut them out.
To make the paper shapes I lay a sheet of good old butchers paper over the area & run my fingers along the edges of the framework, creasing the paper.
Cut the paper about 1/8" bigger.

After trimming & sanding the inboard edge of the panel to match the main stringer, that runs from the tip of the sponson to the transom, they were given a coat of epoxy fiberglass resin on the underside.
The whole inside of the boat was also coated with the resin at this point.
Foam blocks were cut & fitted into all the spaces & sanded to shape.

Then on went the sponson deck skins.
I placed a bead of 1 hour epoxy on all the internal frame work, placed the skin in it's exact place & tacked it down at the transom & at the main bulkhead of the heels of the sponsons.

The left hand skin needed a cut on the underside of it to relieve the pressure where the framework sort of curves down & then levels out towards the chine, creating dip in the skin.
Then I stitch glued around the edges, keeping the skin pressed down & flat. Working forward from the transom. Some CA accelerator in the pump spray bottle is a great thing to have here, as everything is held in place by hand during this operation. The boat needs to be rotated upside down & sideways to get the CA to flow where you want it to go.
Then a bead of CA is run along the joins, a section at a time, allow the glue to wick into the joint then squeeze together & spray with accelerator.

Of course the other method of Epoxy on everything & an array of weights, tape & clamps also works.

Creasing the paper templates.

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The dip in the left side deck.

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The cut in the underside of the deck.

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All glued on ready for final trimming & shaping.

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The left side skin with the dip.

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[lambo]

Are you going to build the tiplets/hydroshoes, at aft end, like the full scale. If so please document with pics, Thanks.

[785boats]

Hi lambo.
I did give them a mention & a photo in post #23.
Here's a bit more detail.
I simply cut, bent & sanded to shape, the bottom ride pad. I chamfered the edge that glues to the anti trip skin to the same angle, & glued it on flush with the air traps. To keep it level I ran a straight edge across from the other side of the boat, & overhanging the ride pad while the ca glue set.
Then the side of the pod was cut & bent to shape & glued on. A little infill piece was added to the transom & then a piece of thin 0.04mm ply was glued on covering the whole transom of the pod to cover the join in the ply.
If I had been thinking properly earlier in the build I would have cut the rear skin on the hull to the correct shape so the last couple of steps wouldn't have been required. Maybe you will learn from my mistake & get it right.
All the edges were sanded to shape.
I had no dimensions to work with, so I just winged it from the photos & videos on the internet.

Because the rear transom is a different shape on each side of the boat, the transoms of the pods are different too. See the pics below.
I hope that helps a bit.

Port side sponson.

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Starboard side.

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[785boats]

I couldn't help myself this morning & had to assemble a few of the bits for the engine. The intake & exhaust manifolds were joined together, as were the 4 turbo casings.
A lot of sanding was then involved in reducing all the banding lines on everything.
Then I coated everything with high build spray putty to fill in the all the lines that were left.
I'm back into the sanding again now,
Man it's hot today. I had to wash the dust down my throat with some Coopers Original Pale Ale.

003.jpg

[Speed810]

Hey Paul......I'm smelling more of that birch ply sawdust clear over here....LOL

I just saw this thread.....great project and the boat is looking amazing! Wouldn't expect anything less! It will be interesting to see how the final turn fin is mounted on this. I'm trying to visualize it. I know on my Elam the sponson heels had that same angled piece coming down just above the ride pad. I ended up mounting the turn fin to the heel of the sponson to get the fin 90 degrees and then built a box shape around the turn fin bracket. Not quite to scale but it worked....LOL

I love that motor.....the things the 3D printing world can put out there is amazing. I actually ordered a Anet A6 ( Prusa i3 clone) printer last week...LOL. Have to build the darn thing first...HAHA. But I am looking at all the things that can be built.....rear wing sets, canards, canopies, drivers...etc. It's endless!

I'll be watching the build as it develops....Looking Great!

Mike

[785boats]

Hey Paul......I'm smelling more of that birch ply sawdust clear over here....LOL

I just saw this thread.....great project and the boat is looking amazing! Wouldn't expect anything less! It will be interesting to see how the final turn fin is mounted on this. I'm trying to visualize it. I know on my Elam the sponson heels had that same angled piece coming down just above the ride pad. I ended up mounting the turn fin to the heel of the sponson to get the fin 90 degrees and then built a box shape around the turn fin bracket. Not quite to scale but it worked....LOL

I love that motor.....the things the 3D printing world can put out there is amazing. I actually ordered a Anet A6 ( Prusa i3 clone) printer last week...LOL. Have to build the darn thing first...HAHA. But I am looking at all the things that can be built.....rear wing sets, canards, canopies, drivers...etc. It's endless!

I'll be watching the build as it develops....Looking Great!

Mike

Thanks for the kind words.
The turn fin bracket won't be a problem. I'll just copy the full size ones. Sort of.
Sounds like you've got some fun in store with that printer.
As for the motor?
Well the paint shop & the engineering shop at Wet Track Racing have been busy.
The motor is ready & awaiting transport to the dyno shop.

It all went together effortlessly. A great little kit from 3dparts.

A few bits painted.

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Start of the assembly.

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All done.

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Another view.

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[785boats]

I haven't had much of a chance to do much to this ol' girl lately.
But this afternoon I cut out some aluminium sheet for the vertical fin tabs & drilled some holes into them for the epoxy to get a better grip. A slight kink at the deck line gives them the outward angle as per the original boat.
They will be glued & screwed to the inside of the main stringers.

Then I cut out the fins .
Each one is made up of two pieces of 1/8" ply with a center section cut from 1/16" ply. This is the same thickness as the aluminium tabs.
A piece was cut out of the ply to match the tabs. The pieces will be epoxied together & then shaped to an airfoil section. When the time comes for final assembly they will be slipped over the tabs with copious amounts of epoxy in the slot.

All the bits.

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The tabs temporarily screwed in place.

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[pescador]

Nice job, looks pretty solid, are you thinking maybe nylon break away screws for the center wing? Maybe magnets for the motor? They always seem to be the parts that take a beating in a flip. Keep up the awesome work man.


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[785boats]

Thanks for the kind words.

I haven't really given the break away screws much thought. But I guess it would be prudent as the wing has such a big surface area.
My 1/8th U-95 has had many flips in the 70mph region. The wing & fins are all solid ply & bolted together with steel bolts & aluminium brackets. They haven't broken yet. But to be fair there is a center fin too. The wing is bolted down onto that as well. Makes for a very strong assembly.

Now that you've brought up the subject, I think I will still have the adjustable angle brackets under the wing, but with nylon bolts through the fins to fasten them. Thanks for bringing it to my attention.

Magnets sound like a good idea for the dummy engine too. Thanks.

[785boats]

I'm glad to say that the egg pod, canard wing, & ramwings arrived yesterday. So now the front end of the boat can be worked on.
Unfortunately the pod is more narrow than the main stringers. So I can't bend them inwards & blend them into the pod as I had hoped.

So, after looking at some images of the underside of the boat I noticed that there is a raised belly pan down the middle of the hull.
I decided to fashion one similar from some 1/8" ply long enough to reach the front of the pod.

The bottom half of the pod was then cut to fit the rear sponson bulkhead & the belly pan was epoxied into the pod.
The pan needed a kink put into it first to follow the lines of the floor pan. This was done by scoring a V halfway through the ply & bending the kink to suit the angle. Some CA glue was wicked along the score line. When the CA sets, the kink maintains a high degree of strength.

Pod & wings.

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The bellypan on the original boat.

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The 1/8" ply pan with the kink & the pod base cut to suit.

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Epoxying the pod base to the ply.

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Sitting in place on the boat.

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[Luck as a Constant]

Build is coming along nicely, Sir.

[785boats]

Thanks for that.
Setting up the framework & skins around the pod is next on the list.

[Navherc130]

You sir, are a building animal. Wish I had the time and storage for more rigs. Always enjoyed reading your posts.

[785boats]

You are too kind.
But let me tell you this. I have nowhere to store this boat. It has to stay on the bench for now, & gently sit on top of other boats when I need the bench space.
Time to sell off some boats methinks.

[lambo]

On your fins, are you going to sheet the adjacent section or will that be part of the hatch? In other words, will your hatch span three bays or just one and you are going to sheet the rest?