Vanguard 14' SEVTEC


FinishedHCAfter two years of construction, the maiden water flight in August of 2009 was made on nearby Hicks Lake in Lacey. The SEVTEC is powered by a Briggs and Stratton, 18 HP V-Twin. The lift fan (6 Blade Multiwing) is direct drive on the vertical shaft and a 3 blade 59" "Ultra-Prop" is belt driven providing thrust. The prop is ground adjustable pitch set at 12 degrees. VHF Marine and Ham (2M) radios are added for communication along with an intercom/headsets for ease of conversation in flight.

HC Purch

On June 7, 2007, I purchased the Hovercraft hull with most of the items needed to complete the project. The basic hull foam and stringers had already been built. The engine was brand new in an unopened box shown on the right. I still spent an additional $2,000 on instruments, lights, horn, wire, hardware, welding, powder coating, and ceconite aircraft dope. It all adds up, even though all the major components were there.
HC WiringThe first part of the project was to begin the installion of the steering system and wiring. I used AutoCad Lite software to make electrical and mechanical drawings before beginning each step. The SEVTEC, INC., set of plans do not have all the details necessary and must be designed as you go. That is why this project was a kick!
Eng FrameThe next step was to fabricate the engine frame out of 1" square stock steel. Plans call for braze welding, but I opted to arc weld the frame. Lining up the engine mounts so the lift blades are exactly 1/8" clearance at the tips within the shroud was extremely critical. I used a square template made from thin plywood shown on the left to accomplish this task. The template was of the engine mounting bolt pattern.
EngFr FinishAfter the engine frame was completed, I had it powder coated and then installed the engine, multiwing lift fan, and thrust prop drive bearings. Also, at this point, I designed the 90 degree belt pully assembly not yet shown in this photograph.
HC CoverThe front and sides of the Hovercraft are covered with "Ceconite," the covering used on wings of Piper Cub airplanes. I used a special aircraft dope to glue the covering to all the stringers, then trimmed the exess material. The next step was to use a heat gun over all the surface to "shrink" the material until it was taut just like the Piper Cub wing. Weight is the key factor here. When finished the hovercraft will weigh 450 lbs. Weight is the key factor here for best performance.
HC PaintDeciding what color to paint my Hovercraft was fun. A lot of craft are white, but I thought red would really stand out. I made a dolly to roll the hull around the shop while working on it, which turned out to be a great help. Later, when working on the skirt, I made the dolly even higher.
HC SkirtNow the fun begins, building the skirt. As you might imagine, there are a lot of curves to cut out using the dimensions in the plans. I discovered it was not the easiest thing to do. In fact, I redrew the skirt plans in AutoCad Lite, so that I could obtain measurements easier to work with. The person I purchased the HC from had a few skirt templates made.There is a total of 13 panels that must be cut out and then glued together.
Skirt AssemAfter the skirt was finished,fastening it to the hull was pretty easy. The green material you see on the skirt is flotation material so when the hull is dead in the water, it gives some buoyancy to the skirt. Water does penetrate the aft skirt through a drain opening with a square flap. Any water in the skirt will then drain out as you begin to hover and move forward, but will not allow water to enter while in motion.
Eng InstalNow that the engine has been attached to the hull and the skirt is on, then the next job is to build the propeller guard, rudders, and finish the wiring of the instrument panel. From this picture, you can see the Hovercraft is starting to take shape.
Prop GuardUsing 1/2" emt conduit and a conduit bending tool, I suprised myself and created a not-so-perfect prop guard. Actually to the untrained eye, it looks pretty good. But it was difficult to get two circles of conduit bent exactly the same. After welding the cross piece braces it was off to the powder coating company again.
HC FinishAll that was left, was to install the mesh netting on the propeller guard, which prevents fingers, birds, hats, and branches from getting into the whirring prop. Initially, I painted the rudders white, but then changed them to blue. The remaining part of the project was tidying up the electrical wiring, installing a horn, lights, and an intercom system between pilot and passenger. I also purchased two folding marine seats and built light weight seat frames.
HC PanelThis is the finished dash with radio and intercom installed. I use David Clark Headsets and can communicate with passenger as well as the radio. The headphones also cut back on the noise. The panel includes a Digital Tachometer, Engine Start counter, Hour Meter, Oil Pressure audible/visual alarm, Voltmeter, Ammeter, circuit breakers and switches. Everything has a function and is not just glitter. The intercom is an Avionics 6 channel Sigtronics SPA-600 with sidetone.
Two removable seats can be moved for proper balance