I've been wanting to build another large craft for a couple years now, so I finally sat down and started working on a design. I'm calling it the Titan for now, and it's a large twin-engine craft with as much open deck space as I could fit. To reduce noise, the lift engine is in the front, and is covered with a forward deck that's also strong enough to walk on. There will be a few more updates coming with installation of the thrust engine, prop, guard cage, and controls, but here's the progress so far.

I'm using a simple flat panel construction method, similar to a Sevtec. To keep things quick and inexpensive, I've cut the parts out from light plywood according to the CAD drawing, and laminated them with a single layer of glass. These are a couple of panels before wetting out the cloth. 

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Here I've assembled most of the pieces of the base of the hull. I use small wooden tabs and CA glue at the joints to temporarily hold the parts together. Here I've started fiberglass taping the corners. I used a 4' x 8' piece of Penske board I had laying around for the rear part of the floor.

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The hull is coming together now. I've attached all of the sides now. The two holes in the front are lift air intakes. I'm hoping noise from the lift engine/fan will largely be confined to the enclosed lift engine chamber, and placing the intakes on the front of the craft will channel the noise that escapes away from the passengers.

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I've added braces cut from 1/2" plywood and ripped a 1"x12" board to make supports for the top edges of the hull. I beefed these areas up because they're designed to be stood on.

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Here I've skinned the top edges of the hull around the passenger compartment, and also added a firewall separating the cockpit from the lift engine compartment. 

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 View looking from the firewall forward into the lift engine compartment. All the inside edges have been taped now.

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 This is the plywood former built for the 26" lift duct

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 Wrapped with 2" foam kerfed on my CNC wire cutter for an easy bend

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 I bonded a couple layers of plywood on the top edge of the deck for bolting down the engine frame.

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Fiberglassing the deck surrounding the cockpit. I've also added a console to mount the steering wheel and controls.

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I've bonded the lift duct into place, and added several vertical braces to help support the deck on top of the lift engine compartment

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 Another view of the console, and some additional taped edges.

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The lift engine! 

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This is the frame I built to support the deck on top of the lift engine bay. It is strong enough to support an adult's weight.

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I've now decked over the lift engine compartment. The gap visible in the far side will be decked but have an access hole for refueling. And the gap on the near side will have a rectangular access port. I sealed that area with a vertical bulkhead, and will use it for dry storage.

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This is the frame for hte lift engine cover. It's also built to stand on.

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I've now flipped the craft over and am taping the edges on the underside. 

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Filling small gaps between panels, and preparing to tape the edges.

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I used a dense 2-part polyurethane foam to fill in gaps around the bottom of the lift duct and provide a radius.

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Sanded smooth and glassed over. I've also started adding landing skids ripped from larger PVC boards.

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The bottom is now glassed and painted white.

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Here is the topside of the craft, all glassed and almost ready for paint. I'll add some more detailed photos in a future post, but I'm also test-fitting the thrust engine stand here.

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 Lift engine bolted to its mount, and being centered in the duct. I'm using a Hascon fan from a previous project that I trimmed down to 26" and rebalanced.

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The plywood pads are for fishing chair pedestal mounts. I've also fitted the Teleflex steering wheel.

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First two colors of the camouflage paint scheme: tan and a medium olive green (flat colors).

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Final two colors: brown and and greenish black! (It just looks black in the photos but it has a green hue to it). I then added three coats of satin polyurethane to protect the paint.

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I hinged the lift engine cover. Now I can pop it open to show people what's under the hood!

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I'm trying to get this craft ready in time for a cruise in May, so I'll be posting updates soon!



# Gone7 2017-01-24 11:42
On some of your other crafts I've noticed that you've used foam core construction. I'm curious why you've decided not to do that with this model. I would assume that the added core thickness associated with the composite foam might add some structural stability, especially across some of these larger panels.
# particleman83 2017-01-25 06:47
I definitely would have preferred foam core panels, or maybe a honeycomb like Plascore or Air-comb, but I wanted to make this build as quick and inexpensive as possible. I had a lot of plywood laying around, and I'm using engines I already had from previous projects. If this works well and I build any more of them, I'll definitely be using panels laminated with 1/2" Plascore, which have the added benefit of built-in buoyancy.
# Kelley 2017-02-02 11:37
What kind of plywood are you using? How thick are the panels?
# particleman83 2017-02-04 08:48
It's ordinary 1/4" plywood with birch veneer on both sides (not marine grade). I wanted to throw something together quick and cheap for testing, and I happened to have some sheets laying around.
# Kelley 2017-02-04 09:24
Cool! How did the hull weight turn out?
# particleman83 2017-02-06 16:01
I haven't had a chance to weigh it yet, but based on how it feels pulling it around the garage, it feels like around 250 lbs or so. It would have been a bit lighter if I had used plascore or foam for the panels, but the plywood ended up being lighter than I thought.
# Kelley 2017-02-06 16:27
That's about the same weight as the original Sevtec Prospector hull. How big is this guy?
# particleman83 2017-02-06 18:37
It is 17 ft long x 7 ft wide. I'm hoping to keep the total weight around 600-650 lbs. That way I can have 800 lbs for payload while keeping cushion pressure below 12 lbs/sq ft. If I built any more of these, I'd like to use Aircomb, which are composite panels I can get locally that are very similar to Plascore. They make extremely rigid panels, and have the added benefit of built-in flotation.
# Kelley 2017-02-09 17:57
Impressive how you're getting the hull that light using fiberglass covered plywood. Plus if you're using epoxy resin and the wood is totally encapsulated the hull could last for years!
# particleman83 2017-02-12 23:40
I hope so! It'll just come down to if there are any pinholes in the fiberglass that I missed. But the paint is also pretty thick and I put on three coats of polyurethane to help seal it. I'm going to make some bag and cushion pressure measurements in the next few days, and that'll help me get a more accurate weight so far. I think future versions would be perfect with panels made from laminated 1/2" plascore.
# Kelley 2017-02-13 06:01
Any idea what a sheet of Plascore will cost? I've tried to source, unsuccessfully, any locally obtained honeycomb core panels a few times in the past.
# particleman83 2017-02-13 07:14
I also couldn't find anyone that sells Plascore within 1000 miles of me. But I found a very similar product distributed by Composites One, which has locations all over:
The product is called Aircomb, by a company called Poly-u-mac. It's not cheap, but I think the 1/2" sheets cost something like $80 each.
# Kelley 2017-02-13 08:28
# WerkSpace 2017-02-18 12:37
You can buy it direct from Plascore.
Luke Walsh
Sales Engineer
Plascore, Inc.
500 E. Roosevelt
PO Box 170
Zeeland, MI 49464
United States
TEL: (616) 748-2239
FAX: (616) 772-6422
# particleman83 2017-02-24 23:35
Thanks! I spoke directly with Plascore a couple years ago, and they seemed very easy to work with. I could buy direct from them, but shipping full size sheets to Texas is pretty pricey, so I tried to find something similar carried by local distributors.
# SEVZILLA 2017-02-27 20:55
Nice camo paint job.

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