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Picture of 10 HP Hovercraft
I was looking for a project that my Grandson and I could build. together. We decided on a hovercraft after watching a TV special. Knowing absolutely nothing about hovercraft we researched the web on the subject  and found the Universal Hovercraft website to be the best source.
We had an old 10 HP Briggs horizontal shaft electric start engine from an old riding mower that looked like it would fit the bill.  We bought the plans for their UH10F craft. We liked it because it only uses one motor. Most hovercraft use a separate motor for lift and thrust. This one directs approximately 1/3 of the thrust air to provide both lift and inflating the skirt. Most of the materials could be found at the local builders supply.
The only parts we needed to buy from Universal Hovercraft were the Plans, propeller, propeller hub, and the skirt material. Although it busted our $500 budget we decided to purchase their materials kit which included all the epoxy,fiberglass , screws, and glue. The skirt is the heart of this thing and we didn't want to save penny's  on something this critical. It was a fun project for the both of us. It would be a great Father and Son project.
 
 
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Step 1: TOOLS AND MATERIALS LIST

Picture of TOOLS AND MATERIALS LIST

Tools required

Table saw to cut 4 X 8 Foam and plywood
Keyhole saw or saws all to cut openings for air ducts
Scroll saw for plywood duct and body peices
Shop vac for vacuum blanket
Two to four saw horses
Several plastic squeegees
Basic hand tools

Materials list

From home depot cost about $80
For the hull
1 sheet 1" white Styrofoam
4 sheets 2" blue construction foam 4 x 8
4 sheets 1 /8" plywood (doesn't have to be marine)
2 12' lengths 1 x 2 lumber( pine is fine)

Hardware kit from Universal Hovercraft  $349
This kit contains every little thing you will need to complete this project including
Plans, fiberglass, skirt, glue , skrit screws,epoxy, and a 24' steering cable

DRIVE KIT from Universal Hovercraft $159
 Includes propeller, hub, and bushings

MISC. $20
Small roll plastic sheeting 2 to 4 mills
Paint

Total cost of the project was around $600 plus the cost of a new or used motor.


Step 2: BUILDING THE HULL

Picture of BUILDING THE HULL
Cut the 2" foam to make a 5' X10' rectangle. This dimension will provide a floatation of 600 lbs. If you need to support more weight double up on the foam. It won't weight much more. Skin the top side with the 1/8" plywood. Cut and glue the plywood strips to the foam, and then glue the 1 x 2 strips to the plywood. With a scroll saw cut the two holes for the lift, and skirt air.Glue a 6" wide piece of plywood across the hull where you will instal the motor support post.

Step 3: VACUMN BAGGING

Picture of VACUMN BAGGING
The underside of the hull must be waterproof . The entire underside is covered with fiberglass cloth and epoxy. This can get a little messy if you are not careful. It is important to get all the air bubbles out before it dries. A simple vacuum blanket pulls everything down tight. Don't let this scare you it is really quite easy. First cover the freshly epoxied fiberglass with a layer of thin plastic sheet. Then cover the sheet with a blanket.
This way the blanket won't stick to the fiberglass. Cover the blanket with a larger piece of plastic sheeting and tape it down to the floor all around the edges Make a small slit in the plastic and plug in the vacuum  hose from your shop vac. Turn it on and watch the vacuum pull it down to the floor. If it won't pull a vacuum check for leaks in the tape. I ran the vacuum for about two hours and did a great job. When you take it apart the plastic will pull of easily as it will not stick to the fiberglass

Step 4: Underside of the hull is now complete

Picture of Underside of the hull is now complete
This is what the underside of the hull should look like

Step 5: MAKING THE DUCT

Picture of MAKING THE DUCT
The duct is made from less dense 1" white Styrofoam. The plans show you how to lay out a curving arc that will wrap around the plywood plugs in the middle. Start by screwing together the two plywood discs to spacers the width of the duct. Wrap thee discs with a  band of 1/8"plywood. After you cut the ducts to the proper shape (arc) Cut kerfs 3/4" deep all around the inside of the ducts so they will bend around the form easily. Be sure and maintain the exact centers of the discs. Later you will drill them out to the size of your motors crankshaft. Don't separate the duct from the form at this time. When it gets to be time to locate the duct to the hull these holes will let you mount the duct perfectly in line with your engine shaft. The plans go into great detail on this step and we didn't have any problems with it.

Step 6: MAKING THE MOTOR SUPPORT POST

Picture of MAKING THE MOTOR SUPPORT POST
Cut a 2 x 4  piece of pine to the length specified in the plans And put it in the hole cut into the hull (center line of craft) Use plenty of epoxy for this. Cut a base plate from 3/4" plywood for mounting the engine. Fit rear legs from pine and drill and screw braces everywhere you can. This will keep vibration to a minimum  I used gorilla glue in every joint. I put epoxy lay ups all around the post for added strength.

Step 7: MOUNTING THE DUCT

Picture of MOUNTING THE DUCT
Temporarily mount the motor in place and drill the plywood disc to the size of your crank shaft. Set the duct in place and align it up with the motor crank. Use shims to assure good alignment. When you are satisfied that it looks straight anchor the duct in place with spray can expanding foam. Put it on heavy as it can be shaped or removed easily with a  knife or file. When it hardens you should have a rigid mounted duct that is aligned with the motor crank shaft lined up with the center of the duct. At this time you can remove the plywood discs from the duct by removing the screws that hold the spacers. It should pop right out.

Step 8: THE PROPELLER

Picture of THE PROPELLER
You can buy the prop two ways, either finished or unfinished. You can save a lot of money by finishing your prop your self.
First slide the prop onto the crank without the hub to see if it fits inside the duct without binding. A duct is most efficient when the prop fits closely inside the duct. Be very careful when removing tip material, it's easy to cutoff but hard to put back . Once you have the tip clearance set you can begin to sand the blades with a power sander and finish by hand. Once you get it smooth you MUST balance it to avoid vibration.
Hang the prop on a rod held in a vise to see which blade is heavier than the other. Don't short cut by shortening the tips. Just keep sanding the blades. Most props are pretty close when they arrive so it is not an undaunted task. Once it is balanced give it a couple coats of paint to preserve it. It's a good idea to paint a white band at the tips for safety's sake. By now the foam is hard so you can cut the bottom of the duct with a sabre saw to conform with the openings in the hull for lift air. Now is a good time to trial fit the prop and hub to the motor to make sure it runs true inside the duct. The motor should be bolted down securely. Turn the prop over slowly by hand. Check for at least 1/8" clearance all around. You can adjust by putting small shims under the motor mounts if needed.

Step 9: BUILD THE AIR CHAMBER

Picture of BUILD THE AIR CHAMBER
The purpose of the air chamber is to divide the air flow between lift and thrust. The picture doesn't show it in it's proper place. We just needed a flat area to glue and fiberglass it together It is made from 1/8" plywood

Step 10: Install the air chamber

Picture of Install the air chamber
Slide the three sided chamber in place and glue or fiberglass in place. I prefer to use fiberglass when ever possible. When the bond is set install the top of the box. You will probably have to put a weight on the rear to hold it tightly to the bottom frame. When it is dry fiber glass the edges and you are done with the air box

Step 11: THE RUDDERS

Picture of THE RUDDERS
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The rudders are cut from 1" foam. Drill holes in the top and bottom to fit dowel pins. Glue the dowel pin in the bottom. The top pin just drops in to allow for removal of the rudder. i used a belt sander to fashion an airfoil to make them lighter and more aerodynamic. Don't make them too thin. Cover the rudders with one layer of fiberglass to give them strength. Glue small drilled blocks at the top of the duct, and the air chamber to receive the dowel pins. Connect the two rudders together at the bottom dowel pin with a short length of aluminum or wood stock. This is where the steering cables are attached. Run the cables through the air box and route them through eyelets to the control stick. Don't terminate them yet until you build the body. We used a 2' long piece of 
of 1" PVC for a control stick. 

Step 12: MAKE IT LOOK GOOD WITH A BODY

Picture of MAKE IT LOOK GOOD WITH A BODY
Start by laying out the basic shape with a marking pen and screwing 3/4" stock to the line. The 1/8" plywood bends easily to conform  to the shape. Next clamp and glue the 3/4" stringers to the top. Fit a 2 x 4 between the sides to form a dash board.This is a good time to attach the throttle cable to either the dash or the side strips. Later on we put a lanyard connected to the kill switch in the dash. This is a requirement if you want to run it in any sanctioned races. Cover the top  with a plywood sheet and fit some scrap foam to form the nose piece. Run the steering cables through the sides and attach them to the stick. Make a little seat that feels comfortable. We padded ours with some foam and scrap vinyl. Paint the whole craft with a couple coats of any paint you may have laying around. We chose white because it stays cool even in direct sunlight. A little trim color makes it unique to you and really makes it stand out. Now that it is painted is a good time to add a screen to stop wayward hands and arms from geting into the prop area. That could ruin a good day. We had some left over wire fencing and fashioned a guard from that.  We also added four lifting handles in the corners to aid in lifting it on and off a trailer.

Step 13: THE SKIRT

Picture of THE SKIRT
I am sorry that I didn't take pictures of the skirt installation but the plans go into great detail on this step. I put the craft up on horses to make it easy to get at the inside attachment. The key to a good skirt is in the corners. They are over lapped and glued with the special glue tat is supplied by Universal Hovercraft. The skirt is held in place by 200 stainless screws and washers. The only tricky part is the screws around the rear of the air box. The skirt is very rugged and we have not had any trouble with it.

Step 14: THE BIG DAY THE TEST DRIVE

Picture of THE BIG DAY THE TEST DRIVE
The first thing we did was to drag it outside and start it up to check on how it hovered. The skirt filled up with air at a little more than idle and we could push it around easily. We gave it more throttle and it began to move forward. My grandson got in first and drove it all around the back yard. It seemed to respond good to steering control but we learned that it tends to side slip if you are going too fast when you go into the turn. Next I got in and also had good results. Time for the water tests. We took the hovercraft to my best friends house, he lives on a 1000 acre lake and has a small beach to launch from. The craft floats well on it's own and with a person that weighs 200 lbs. I elected to be the test pilot and put on a life jacket for safety. Starting the engine brought it up to a nice hover. Increasing the throttle a bit started the craft moving forward and away from the beach. More throttle and it began to move forward more briskly. It seemed to handle really good. at full throttle until I tried my first turn. To my surprise I started to go sidewise and then backwards. With a little experience I learned to lean my body into the turns and reduce throttle slightly and was able to negotiate the turns much better. I don't know how fast I was going because I don't have a speed indicator, but I left a pretty good wake. Leaning forward seemed to increase the speed. When my grandson took his turn he seemed to go a little faster than me and he was riding more level than I was. I think maybe the seat should be a little more forward. We really had a blast and 8 or10 people of all sizes and weights tried it out. The heaviest guy weighed around 300 lbs. Although  it floated well, he could not get the performance that we could. Under 225 lbs. was O.K.
We played for 2 hours and burned two tanks of gas and didn't have any problems. All in all it was a great test day, This craft is fun, easy to drive, and proved to be very safe. Our youngest pilot was 10 or 12 years old . My only other comment would be to install a quieter exhaust as the neighbors were not impressed with the noise. It attracted a lot of attention as many people had never seen a hovercraft before.

Step 15: A SHORT VIDEO

Some how I misplaced the longer video

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buck221727 days ago

Great idea

hussaina11 month ago

dear sir can you please display the list of components used including woods? materials? engine parts? prop materials? either wood or metals? how the duct is taken from the main engine as bleed to inflate the skirt? route? and how air is send under it to make cushion? is skirt is auto deflated when engine is switched off? does it also climb? can override speed brakers? footpaths etc? asif

hussaina11 month ago
JoshD32 months ago
Could I switch out the motor for something bigger?
fortneja3 years ago
I built a UH-10F myself back in high school. I was slowly putting together an instructable for it several years ago, but it was taking too long, so I gave up. I can send you my notes and photos if you want to elaborate on some of the steps.

I originally used the rope and pulley system specified in the plans for steering, but later modified the steering to use bicycle cable, which was much more durable and responsive.

Hi,

I am trying to build an UH-10f.

it would be of great help if you could give me those notes which you prepared.

yhank you.

please get back to me at adith2050@gmail.com

Dear Fortneja, I just saw your post and wondered if I may take a look at your notes and photos for the UH 10F? I am about to build one and would grately appreciate
Thank you,
Dan Farncombe: Danfarncombe@gmail.com
Very cool! How Much does it weigh?
mickydee (author)  hover_crafter3 years ago
I am not absolutely sure. I would guess about 125 lbs., maybe 150.. The engine and prop are the determining factor. The bulk of the craft is made of very light weight foam and 1/8" plywood. If you go to larger motor with electric start, you could double up on the foam quite easily.
mickydee
Thats alot
Its awesome
Wow! Intresting
Jackylee5 months ago
Nice . I'm Vietnamese
Please sent me plans , I don't understand under the boat work . Thanks
Jackylee Jackylee5 months ago
Please share me plans thank you !
bdubu7 months ago

Great instructable Roland! Thanks for sharing! BTW, judging from your bio, I suspect you'd be right at home at the wheel of Rudy Heeman's hovercraft (https://www.youtube.com/watch?v=CTM8rcA7c04).

bbfly8 months ago

I have the plans for this hovercraft. Your assembly steps will make it easier for me to put it together. Thank you very much

ninjabatman10 months ago

this is super awsome

mickydeejr10 months ago

this is boss

coolboy1011 year ago
Hi there, I know this instructable is getting quite old now, but I am thinking of building a hovercraft as a school project, and this one seems relatively simple and your guide is really helpful! Unfortunately, being in the UK I cannot get the plans to this hovercraft easily or buy any of the kits, so would like to ask a few questions if that's ok.

1... How large were the pieces of plywood? The hovercraft is 10ft x 5ft and I can only find 8ft x 4ft plywood. Did you have to join more than one piece together? If so how did you do that?

2.... What parts of the hovercraft were actually fiberglassed? Not the whole thing presumably, just the joints?

3.... Is any type of foam acceptable? I have found some 50mm (2") Styrodur which is "extruded rigid polystyrene foam (XPS)" with a compressive strength of 300 Kn/m². Would this be acceptable do you think?

4... How powerful should the engine be? I have found a brand new 13hp engine for a good price. Would this be a good size or will it be overkill or too heavy?

Any help would be much appreciated! I am sure I will find many more questions needing answers, so if you could help that would be great.

Thank you!
SofiaM2 years ago
How big is this hovercraft? 4 by 8, or 5 by 10? Thank you
mickydee (author)  SofiaM2 years ago
The hovercraft is 5 x 10 overall. I bought it at a local builders supply in 4 x 8 sheets.. After it is covered with the 1x4 plywood and fiber glass the joints are all covered. Alternate the joints between the foam and plywood for strength.
Mickydee
SofiaM2 years ago
How big should the sheet of 1" styrofoam be? Thank you!
BoSkarr2 years ago
This is amazing. I plan to start one that want to hald more than one person. This is a great guide, as I can't become a member of universal hovercrafts because I am 14, don't have a job, and I don't have a phone. I have a couple friends who will help and I can't stress it enough how amazing your hovercraft looks.
you should enter the epilog challenge V if you can
shull32 years ago
Congratulations on a successful first build.
This is a great project for Father/Grandfather and Son/Grandson. Universal Hovercraft http://www.hovercraft.com/content/ is a great company for DIY hovercraft projects. I build a UH12T4 with my high school soon back in 2002 -2006. We have had a great time with it and now belong to the http://www.hoverclubofamerica.org/ Hoverclubofamerica. The club has great resources for recreational hovercrafting throughout the USA. Most of the members have either built or operate a homebuilt hovercraft. If you and your Grandson get into this hovering more be sure to check out the HCA. We sponsor over 20 events a year at many locations around the country. http://www.mapquest.com/?version=1.0&hk=7-HQDmHdt9#dd126f889ef3d31a8d5316c6  Here is a map of the locations for the 2013 season. Hope to see you at out hovering this year!

Scott Hull


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I was wondering if I could use any type of epoxy or is there a certain type that would work a lot better? What would you recommend.
mickydee (author)  phynicfirebird4 years ago
I always use the cheapest I can find. Tru to use something that is easy to mix, like a 2 to 1 or a 3 to 1 ratio. Any epoxy you can get will work. You will need about a gallon.
mickydee
Mr. Dee, I'm stoked. I'm in the third world and this is the thing to have.
I can get most parts here
Can you tell me a ratio to increase the size to accommodate 2 people or 180 more pounds
Thank you....i am hoping to build my own from scratch this summer without any kits...the only problem i have is that since i am only 16 and do not currently have a job (wish i did) it is going to be hard to get the money but i am hoping to get a job real soon then start saving for the parts.
council cleanup days is your answer
gear7622 years ago
Your project is pretty sweet! I plan on building a hovercraft for a science fair at my school, but as of yet, no one has any description of how to put on the skirt or what size/how many holes to cut out for a 4ft by 8ft hovercraft. If you could maybe send me a few pictures of the skirt, as well as some basic instructions on how to put the skirt on and cut out the holes, that would be great! Thanks!
Xthinker2 years ago
I cant seem to find the website, can you post a link to it? I'm interested in making one
dirt_hawker2 years ago
How much do you and your grandson weigh? How would you describe the diffrence in weight and perfermance?
vlxwgn4 years ago
Do you have any more information on the skirt installation? Did the skirt you bought come with instructions? Other than that awesome :)
mickydee (author)  vlxwgn4 years ago
Hi!
Yes the kit come with very good instructions on cutting and installing the skirt
I was lucky, Grandma is a seamstress and added her touches to it. Don't let that stop you
mickydee
mrtomc mickydee2 years ago
I have a UH-10f that I purchased already built. It was never used. I had to fabricate a rudder stick and add a throttle cable. Both work great. I had it on the lake yesterday and it got 19 mph on the gps. The only trouble i have is that I get water in the skirt inflation hole and I have to drag it up on shore to drain it. There is a slit in the bag in the right rear that i used to drain the water. Should i make some ductwork to raise the intake hole to keep water out?
mickydee (author)  mrtomc2 years ago
I did not have that problem. Your center of gravity may be more to the rear than mine. Adding a riser around the port should fix your problem.
have fun
mickydee
mickydee (author)  vlxwgn4 years ago
Good idea I don't think they had that one when I bought my plans
mickydee
Does the skirt inflate when you start it or it stays inflated? Looks like fun!
mickydee (author)  bnsfwarbonnet3 years ago
A portion of the prop air is diverted to the skirt port and inflates when the engine is started. The craft wont sink when the engine is off because the deck is made of enough foam to keep it buoyant
It is a lot of fun Mickydee .
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