Hovercraft Project

[Jason]

Btw If you turn your hovercraft into a submarine I want to see a video of everybody's reaction to the strange turbulence under the water, thick black smoke bubbles coming to the surface, and the beautiful stainless steel "snorkel" air intake sticking out of the water!

Haha that would be awsome. Id also love to see that.. I could only imagine the look on some boaters face when this pipe goes past them puffing black smoke.

[MigPlazArc]

Haha that would be awsome. Id also love to see that.. I could only imagine the look on some boaters face when this pipe goes past them puffing black smoke.

It would be awesome! Be even better to put a hinged rain cover "chinker thing" (I don't know what they call them) on it lol

[Jason]

It would be awesome! Be even better to put a hinged rain cover "chinker thing" (I don't know what they call them) on it lol

aw yes I know what your talking about.. That would be even better lol.

[EmptyNester]

Off a couple days because I drove a cotter pin deep into my finger (darn HF trailer kit). Nothing a couple hours in the ER and a couple stitches won't fix.

The next step I did (last November) was to build the duct for the lift fan. They recommend an 1/8" clearance between the fan tip and the duct wall. The wall is made out of 1/8" marine plywood. It's amazing how you can bend that stuff. You glass two pieces together, then glass the outside of the wall. After that you wrap it around a form.



The next picture shows the top deck after I cut a hole in the hull and fiberglassed the lift duct in it place.

[EmptyNester]

The first picture shows the bottom after it's been finished and painted. The skirt attaches on the unpainted wood on the edge of the hull and the inside attached on the wood strip at the top. You can see a hole between the inner skirt attach strip and the outer edge of the lift duct. That is how the skirt is inflated.

The next picture shows the mounting strips for the cockpit wall and the center seat. The center seat also covers the steering mechanism and the lift fan drive belt.

[EmptyNester]

You use two part marine foam to fill the void between the cockpit walls and the lift duct. The foam is as strong as a glue and it gives some structural integrity to the lift duct.



The foam expansion rate is based on the temperature. At 70 degrees it doesn't do much. They recommend 80 degrees. I did this in March, so it was pretty cold. I ran the torpedo heater pointed at the void I was filling. I poured the foam when it was about 105 degrees. It grew like crazy.

The last picture it after trimming the foam and glassing a piece of 1" foam insulation on top.

[MigPlazArc]

So how long is this boat and how big are the air motor blades gonna be?

[EmptyNester]

It's 14 1/2 feet long and about 6 1/2 feet wide.

The lift fan has 4 blades and is 22" in diameter. The prop for propulsion is a normal 2 blade prop and is 56" in diameter.

[MigPlazArc]

It's 14 1/2 feet long and about 6 1/2 feet wide.

The lift fan has 4 blades and is 22" in diameter. The prop for propulsion is a normal 2 blade prop and is 56" in diameter.

That ought to fly lol

[I_Love_Plasma]

It's 14 1/2 feet long and about 6 1/2 feet wide.

The lift fan has 4 blades and is 22" in diameter. The prop for propulsion is a normal 2 blade prop and is 56" in diameter.

Is the one 26 HP engine going to power all of that prop? Are you going through two gear boxes or just one with two output shafts?

[EmptyNester]

I Love Plasma -

My build only has a single engine and it uses belts. The sheave size is used to set the ratio of lift to thrust.

The lift fan has an 8" sheave while the prop has a 12". The sheave on the engine is the same size for both belts.

[I_Love_Plasma]

Okay I understand that part now. But one prop will be blowing towards the back of the craft and one blows down correct? How are you belt driving both props having both the props' shafts being perpendicular (If I am understanding the design correctly).

[EmptyNester]

You do understand it correctly.

If you look at one of the first posts there is a blue print drawing. At the bottom of the mount for the prop there are two idler pulleys that give it a 90 degree bend.

[I_Love_Plasma]

Ah I see. Still a little confused. I will be keeping a close eye out for pictures, I think it will be easier for me then.

haha it's going to be done just in time for the rivers to freeze over, so either you'll have to wait til spring or have a cold ride out on the ice!

[EmptyNester]

Ah I see. Still a little confused. I will be keeping a close eye out for pictures, I think it will be easier for me then.

haha it's going to be done just in time for the rivers to freeze over, so either you'll have to wait til spring or have a cold ride out on the ice!

They say that they run fastest on ice. Not sure the cold weather operation has much appeal to me though. Plus, any breakdown is more interesting.

[DaveO]

cold weather operation

If there was a light snowfall you could blow snow off the driveway and get the mail in the same trip!

[I_Love_Plasma]

They say that they run fastest on ice. Not sure the cold weather operation has much appeal to me though. Plus, any breakdown is more interesting.

Yeah, it's not a simple "drive the pickup and car-trailer out with 6 big guys" retrieval. !! Yeah as you said interesting situation

[EmptyNester]

The thrust duct goes around the prop. If built correctly, they say you can get up to a 15% performance improvement. The first step was to build the form to bend the 1/8" plywood on. Then, cut the wood and fiberglass it together to get one long piece. The first picture shows the wood duct build on the form.

After that, you need to cut 2" foam to a specific arc to wrap around. It needs an arc rather than straight cut because you need to form the foam into a wing shape. So, compounding the precise arc of the plywood and the precise wing shape you form with the foam - it didn't go very well.

I got to the point of "this is no longer fun". So, I did the best I could just so I could move on. I ended up having to cut the foam into smaller chunks so I could work with it and get it to fit. Then, I either filled the gaps with foam or just glassed over them. Worst case, I can always redo it later and replace the one I did. A picture of it with the foam partially installed is below.

[EmptyNester]

Not being a particularly artsy or talented at graphics design - I decided to go with a military look. I used "battleship gray" for the paint and I painted the props similar to military plane props. (Cheesy - but hey, it's the best I could do.) Friends have suggested I mount guns on it

The model is called the UH-14P, so I figured I'd do a big "UH-14" on the sides of the thrust duct.

[I_Love_Plasma]

type in "kari byron machine gun myth busters" on youtube THATS what you need minus the incendiary rounds .

Which prop is for lift? the big one what looks like maybe 40" blade?