Hovercraft Project

[EmptyNester]

I posted my second project. It's to reinforce the prop platform to prevent the platform from breaking free and the prop flying forward. Plans called for 1/8" aluminum, but that just didn't seem sturdy enough for me.

I ended up using 1/2" conduit with angle on each end for mounting.

http://www.everlastgenerators.com/fo...om-EmptyNester

[ogorir]

I was referring to something like 1/8"x2" flat stock in mild steel. my dad always called it strapping, so I do as well. it's cheap and easy to bend and should hold the edge together pretty well.

Lots of good ideas.....

I haven't looked for the material to make the guard yet. I'm not sure if it isn't actually the hardware cloth that I'd end up getting.

I think fabbing my own would be good, except I'm just getting started with metal and I'm guessing it wouldn't look that good.

One of the other things I've heard mentioned is that another purpose of the guard is to contain pieces should the prop break/fragment.

Ogorir - do they make banding material in anything other than stainless? I only have MIG and have only worked with mild steel so far.

DVA - I've seen videos of hovercraft running on dirt. Looked like it would be a mess. When I get it done, its going to kill me not to be able to cruise around the neighborhood to test it. I live in a plan - so that wouldn't go over well plus the roads are a little too narrow for comfort. It's going to be interesting that the test flight will also be my first training flight.

[EmptyNester]

I was referring to something like 1/8"x2" flat stock in mild steel. my dad always called it strapping, so I do as well. it's cheap and easy to bend and should hold the edge together pretty well.

So, would you put the 2" parallel to the guard or perpendicular? I'm trying to visualize how you'd attach it.

With just the fence material bent and welded, you could probably use some type of small clip to secure it. I'm not sure how you'd attach the strap.

They tell you to put six layers of 6 0z. fiberglass where you plan on using screws to hold the thing on since the duct is just foam.

[EmptyNester]

These pictures will bring the thread up to the current state with respect to the major stuff.

The first picture is the completed thrust duct. Didn't turn out nearly as nice as it was supposed to, but after putting 50+ hours in on it - it stopped being fun. I'm under orders to have the garage cleaned up by the time snow flies so that my wife can use her side Given her tolerance for this project, that's a "gotta do".

You can see from the picture that there are cut outs for where the duct mounts to the deck. There are two 2x2's on the deck. In front of the duct the prop platform and engine are mounted on them. Behind the duct the rudders and trim wing are mounted on them.



The next shot shows a head on view with the duct attached. I've since added a horizontal duct support that goes from the prop platform to the duct. I need to add a support to the top of the duct yet. I was thinking of fabing a support using conduit.



The final picture shows my Project #2 already posted. This reinforces the prop platform to prevent serious danger on failure. You can see the horizontal support there.



I'm currently working on a number of smaller things:
- final fiberglass on the duct itself
- mount for strobe light (required by Coast Guard)
- mounting blocks on deck for pulleys to handle control cables
- bench seat in back of cockpit

Hoping to get it done sufficiently for final paint in the next couple of weeks - before it gets too cold.

I'll continue to post pictures as I make progress.

I'll probably be doing the control stick soon using conduit and the welder to fab a stick for steering and trim (will be Project #3).

[jerky]

thats looking really nice. it will be alot of fun once your done im sure!

[EmptyNester]

Thanks.

Its at the frustrsting point as its just a lot of smaller finish work that will seem like it will take forever. Plus, once its done I've been told it will take about 2 months to get a boat registration.

[Jason]

That waiting would suck.. I would probably be playing with it before that came...

[Tritium]

Boat registration ? It doesn't float on water, it floats on air .

Thurmond

[ogorir]

So, would you put the 2" parallel to the guard or perpendicular? I'm trying to visualize how you'd attach it.

With just the fence material bent and welded, you could probably use some type of small clip to secure it. I'm not sure how you'd attach the strap.

They tell you to put six layers of 6 0z. fiberglass where you plan on using screws to hold the thing on since the duct is just foam.

I'd weld it perpendicular to the fence panel so your guard has depth. seeing as everything on this is made of foam, you might want to go with something thinner than 1/8" to keep the weight down. 18ga would probably be fine. just weld the fence panel to the strap and weld mounting tabs to the strap. you'll still need to bend the ends of the fence panel up, though. you're not going to get a good joint trying to weld something edge-on to the fence panel.

[I_Love_Plasma]

Hopefully you or someone you know has an HD video camera to record you once it's done! I want to see this thing ZOOOOOM!

[redbeard]

Boat registration ? It doesn't float on water, it floats on air .

No kidding, assuming they ask for the displacement on the forms, I would think a "0" would kick it out of the boat classification all together.

Are you expected to get a license plate too to run it on land?

[ogorir]

No kidding, assuming they ask for the displacement on the forms, I would think a "0" would kick it out of the boat classification all together.

Are you expected to get a license plate too to run it on land?

might count your blessings they don't make you register it as a plane! I'd wager that costs more than either.

[EmptyNester]

Some states apparently require registration as both a boat and an ATV. I didn't ask as I'm sure they say yes if they didn't know.

It will run on land. It just can't do long grass. Also very subject to cross winds. So I haven't been able to find a place on land to try it.

Still have to build up an HF trailer kit to haul it, once its done.

[EmptyNester]

I'd weld it perpendicular to the fence panel so your guard has depth. seeing as everything on this is made of foam, you might want to go with something thinner than 1/8" to keep the weight down. 18ga would probably be fine. just weld the fence panel to the strap and weld mounting tabs to the strap. you'll still need to bend the ends of the fence panel up, though. you're not going to get a good joint trying to weld something edge-on to the fence panel.

I think I can visualize that. It seems like it would have a very "polished" look. Could probably even put the strap at the same angle as the face of the duct to fit into the front of the duct.

[EmptyNester]

might count your blessings they don't make you register it as a plane! I'd wager that costs more than either.

You should check out the uh-19rxw hoverwing at www.universalhovercraft.com. It has removable wings, runs on a Subaru car engine and get about 10 feet high with ground effect lift.

[EmptyNester]

On Saturay I got around 12 hours of work on the hovercraft (mostly fiberglass) and today I got about 9 hours of metal fab done (other posts for an update on my project 1 and also did project 3 and 4 and started work on project 5).

I made major progress on the rudders (there are 4). I had to shape then. I did the front with a small stationary belt sander. I cut the shape on the back with a little 6 amp battery charger and ni-chrome wire as a homemade hot wire cutter.

After that I sanded them down to get them in decent shape. I also got one side fiberglassed on all of them.



I did some fiberglassing inside the cockpit. The big things on the outside were installing the wood strip that the bottom of the windshield will mount to. I got it epoxied down and partially glassed in place.

It's not obvious from the picture, but I also got 4 layers of 2" wide 6 oz fiberglass at the top of the lift duct. That's there so that I have something to I can screw into to attach the safety fence above the fan blade.



The last thing I worked on is the back. I got a piece of foam mounted and a piece of wood mounted on top of the thrust duct. The foam is to mount the strobe light and the wood is to mount a boat running light.

The wood tabs a little more than halfway up the sides are to mount the trim wing and rudders. The top tab was installed first at the wrong height. So I got the second one mounted at the proper height. I figured I'd just leave the first one there and think of it as the "fins on the cadillac".

I also got the wood cross member at the bottom in place. That's to support the bottom of the rudders.



The blue moving blanket is there because I started fabricating the upper duct supports out of angle iron and 1/2" conduit. I put that in place for when I did tacking. Not the smartest thing, since it's not fireproof, but it does the job in a pinch. (I have an extinguisher handy, just in case.)

[EmptyNester]

My fifth project was a duct reinforcing bar. The plans called for aluminum mounting plate and 1/4" plywood.

I guessing that if this is heavier, its only slightly heavier than a wood and aluminum strut.




I built the reinforcing bar today and also fiberglassed the second side of the rudders as well as some other small things.

Next I'll sand the exterior of the craft that hasn't been painted and paint it. I'll probably do that while I'm finishing the rudders.

After the exterior is painted and the rudders are done - it's just the interior. I'm going to use indoor/outdoor carpeting on the floor and walls. I'll also need to build and wire the dashboard and put the controls in.

[EmptyNester]

Haven't been on the forum for the last week as I've been working 12 and 14 hour days.

Worked a regular day and ended up doing some touch-up fiberglassing and started painting. With the marine paint I've been using it usually takes 3 coats. I'll post pictures in a couple days when I have the exterior painted.

[DaveO]

I read that when Burt Rutan designed the plane for non-stop round the world flight, to reduce weight he painted the upper surfaces of the plane to protect against rain and left the undersides unpainted to save weight.

How much does weight reduction come into play when you're building? Do the designs talk about accommodating various weight configurations? (Pilot weight, sumo wrestlers as passengers, etc)

[EmptyNester]

I read that when Burt Rutan designed the plane for non-stop round the world flight, to reduce weight he painted the upper surfaces of the plane to protect against rain and left the undersides unpainted to save weight.

How much does weight reduction come into play when you're building? Do the designs talk about accommodating various weight configurations? (Pilot weight, sumo wrestlers as passengers, etc)

If built to plan, they say the weight capacity is 850 lbs. But they also say the most common mistake is adding too much extra weight when building. I didn't make any really significant deviations, but did add weight. I fiberglassed the bottom and painted it instead of leaving it bare foam.

I would doubt I added more than 50 pounds.

The plans call for an 18 to 24 HP engine. I went with a 26.

I also went with a bigger craft than I originally intended because I'm a big guy and they recommended this one two carry two "full size" adults. That should be fine for me since my wife has been very consistently been telling me she won't ride it.