TOPIC: HOVERCRAFT

The Norm Banner

 

The Beginning

In late 2012 while flying from Brisbane to New Zealand for a project I read an article in a Top Gear magazine about the Pal-V, a motorbike/autogyro.  The Pal-V turned out to be very expensive and a close friend of mine I was working with in New Zealand showed me the Universal Hovercraft web site and the flying UH18SPW.  I loved the idea and the costs appeared reasonable.

UH Yellow Flying

In April 2013 I have read a lot about the hoPal V One 11vercraft and I contacted the Queensland Harbors and Marine who regulate boats.  I was told that there were no issues registering and using the craft in Queensland because a large “WIG” craft, Airfish – 8 (Flightship 8)  had been built in Cairns, Queensland and the authorities had developed all the rules.  Basically that there aren’t any rules, on the water it is a boat and follows boating rules, in the air it follows recreational aircraft rules.  The only real issue is the take off speed because Queensland has a blanket 80 Kmh except for some lakes and ski areas.

The craft was named “The Norm” before it was purchased.  My father in law had wanted to build a hovercraft some time ago and had purchased plans but never built the craft.  My wife asked that the craft be named after him, Norman.  My daughter made me a lifeguard ring as a fun present and she called it “The Norm” because she said that it wasn’t so that is the name as it fits both suggestions.

I purchased a fully built UH18SPW that was undercoated and the craft was not “finished”.  My idea was that I would never finish a craft from scratch but I can “play” with things.  I am a petroleum Engineer and working with oil rigs I tend to be a little rough so I wanted someone else to do the construction.  I also got a close friend of mine “Keith” to paint the craft because he was a painter, I did the interior.

I had a week’s training in November 2013 at the Universal Hovercraft facility in Rockford, Illinois and really enjoyed the experience.  Universal mad it a great week and I was impressed with the guys.

IMG 2089

IMG 2422

Arrival and finishing

The craft arrived in a container in July 2014.  The first issue was that the trailer was built as an American trailer and was too wide to be allowed on Queensland roads.  The trailer had to eventually be narrowed by 50mm each side to meet regulations.  The tow hitch and safety chains and lights had to also be changed to meet Australian Regulations.

IMG 2429

IMG 2609The finishing consisted of painting, insulating and finalizing the cockpit with carpet and further gauges. 

The cabin was removed and a two pack Polyurethane water soluable marine paint was used.  There were 3 undercoats, 4 colour coats and 6 clear top coats before the finish looked as good as I wanted.  The paint has demonstrated that it is very durable and strong and resists small dints and scratches.  The paint was Aquacote by Boatcraft Pacific in Brisbane.

IMG 2740

IMG 2741

 

The sound insulation was three products from Megasorber in Melbourne Australia.  I used a heavy duty sound insulator between the engine and the cabin, C50.  It is marine rated and was placed in the engine compartment.  On the walls of the engine compartment and around the lift duct I used a much lighter insulator, FG.  On the cabin walls, floor and the tunnel with the controls a vibration damper, D14 was used to stop the vibration in the craft.

IMG 2745

megasorber Application

The sound adsorption worked and it dropped the sound in the cabin to about 60db although there was bearing and pulley noise and the thrust prop. 

The interior of the cabin was lined with indoor/outdoor carpet, a lightweight motor racing seat was installed for the pilot, a stereo system, a marine radio and mounts for an ipad, iphone and personal safety devices ( a SPOT and an InReach).  

The craft hit the water in early October 2014 on Somerset Dam.  The day was eventful because the variator had no display and the electric drive overdrove the position making the rear belts very loose and so they jumped off causing no lift.  This was fixed and several runs made.  I achieved a top speed of 88 Kmh and was pleased.

IMG 2795

Several uneventful cruises were made in late 2014. 

Propellor damage January 2015

After one cruise where there were a lot of boats in a small area causing high sharp waves that hit the thrust prop it was noticed that there was considerable tip damage on the prop.  The prop was taken off and covered with carbon fiber and Kevlar along the leading edge and at the end of the propeller.  This has prevented this from reoccurring.

 Prop Damage 1 IMG 3173

Cabin Heat January 2015

The Australian heat and sun made conditions in the cabin very unplesent.  The cabin got far too hot.  Holes were cut into the sides and Perspex motor racing vents installed.  These vents only worked when the craft was turning as the shape of the

cabin prevented air from getting to the vents.  Two marine hatches were installed in the roof of the craft just behind the pilot.  These hatches allow a great deal of air into the cabin and this has solved the temperature issue.  The cabin also allows the sun to beat in.  The top of the cabin was coated with dark car window tint and this was removed the sun issue.

IMG 3516

First real Damage - the exhaust March 2015

The exhaust came loose after a cruise in March 2015.  The flexible coupling had broken.  It is thought that the long sea journey caused the exhaust to continually flex and it eventually failed.  There was also “dints” in the bottom timber rails where the hovercraft sat on the trailer rollers supporting the rough journey theory.  The problem was the location of the coupling as it was inside the engine compartment under the engine and virtually not able to be worked upon.  The craft was taken to a motor vehicle performance shop that were used to these difficult tasks.  I cut the coupling out from inside the exhaust using a Dremel cutting wheel.  The performance shop, DriftKing Performance, welded the new pipe on from the inside and moved the flexible coupling outside the bodywork.

While the craft was out of the water a display was installed on the variator so that it’s position could be easily seen by the pilot.

IMG 3247 IMG 3292

 

Ware on skids – June 2015

The ware blocks on the bottom of the craft were damaged and the timber runners the craft lands upon were also being damaged.  The blocks were covered with Kevlar and re-epoxied.  The wooden runners were covered with a strip of UHMWPE plastic strips screwed onto the timber.  These runners and blocks are wearing well.

IMG 3357 

Further Damage – Running into front of my Jeep – July 2015

After a very successful cruise I came up the boat ramp and spun around in front of my Jeep Wrangler. There was a reasonable wind and the wind pushed the craft close to the Jeep.  The Marine aerial mount hit the Jeep and was torn off.  The wall near the aerial was cracked.

The repairs did not appear difficult but the fuel tank was immediately behind were the craft wall was cracked and the tank was permanently attached in the craft.  To repair the crack a ply piece was prepared with loose fiberglass epoxied to the bottom.  The plan was to push the ply behind the tank and pour epoxy down the ply between the ply and the broken side wall.  When the epoxy was in place the ply would be pushed hard against the wall with blocks or foam between the tank and the ply.  This system worked.

The aerial was re-installed and the cracks repaired with little lasting evidence.

IMG 3490

Engine failure at 16.3 hours, December 2015

In December 2015 while cruising for about 30 mins the engine overheated and basically died.  At this time the hovercraft had 16.3 hours on the hour meter.  What had occurred was the coolant had formed an air lock over one cylinder that caused the cylinder to heat rapidly and burst the head gasket.  This pressured up the coolant system, blew out the “O” rings on the cylinder inlet pipes and dumped all the coolant.  With no coolant in the engine the temperature gauges did not rise until the engine was very hot and unusable.

On inspection the engine was unusable, the engine wiring had melted and it was also unusable.  In removing the engine it was noticed that the mechanicals of the hovercraft were failing.  The 8 bearings were all “rumbling” and the shafts were corroded.  The idler pulleys were very loose and would have been very noisy.  The decision was taken to replace the mechanicals when the engine was replaced.  The work was done by DriftKing Performance as they had been helpful with the exhaust issue.

The variator was sticking and it’s shaft was not stainless so it also came out.  The Chinese bearings were all replaced with sealed spherical roller Timken bearings from Timken.  These bearings were thicker than the original bearings and the base of the housings had to be machined.  The shafts all had to be changed as the bearings were larger ( the seals) and the shafts only had to have keyways where they are required as the bearing seal areas needed solid shafts.

The idler pulleys were also shot so they were replaced with Aetna pulleys.  These pulleys lasted about 2 hours and were replaced by solid steel idlers with high quality sealed deep grove ball bearings.  The front pullies were found to be out of alignment with the position of the belts and that would have caused the belts to continuously rub on the friction blocks.  There were also some screws near the lift duct that were too long and were coming in contact with the belt.

The original engine had the oxygen sensor and the air flow sensor not installed.  This must have caused the engine to run very rich.  The radiator had rusted and was unusable and the exhaust extractors were cracked.  The radiator was replaced with an aluminium Jeep radiator and the manifold of the Subaru was used with a chrome exhaust and tailpipe and resonator. 

The new engine was a fully balanced EJ22 with high quality rods, pistons and rockers so that it can run at 4000 revs all day.  The engine now has all the sensors and reacts normally with the throttle.  A feed has been taken off the Hovercraft speedo ( A GlowShift GPS driven speedo) to give the engine a velocity signal and that has solved some missing signal issues.  All the water pipes have been replaced with pipes that have upset ends and repositioned.  The radiator has an overflow tank to stop the water being pumped out.  The original exhaust system was all cracked but it originals was a 3 ½” system and was also too large leading to low back pressure on the engine.  A standard manifold was used with a 2 ¼” system and similar looking muffler.  The manifold was ceramic coated so it runs reasonable cold.

To do all this work there were “hatches” cut into the original cowling around the engine.  This allowed the engine to be removed through the hatch and will also allow the engine to be easily worked upon.  The hatches that were cut out have been rebuild so that they can be bolted back in place to restore mechanical strength in the engine cowling.

 IMG 9146IMG 4711

An engine monitoring system has been installed to prevent heating again and there is a new oil temperature gauge and fuel pressure gauge.  With the new gauges and a new air speed indicator the cockpit is very full.

Another benefit of the new bearings and pulleys was the noise.  The noise level in the cabin is very reduced and it is now pleasant even when you do not have earphones.  The passengers can talk to each other without shouting.

New Engine MarIMG 5349Repair to decking – June 2016

When the craft was in the DriftKing workshop it was identified that some of the decking was not connected to the underlying foam.  In manufacturer the foam is epoxied and covered with ply, vacuum bagged and then fiberglassed.  The ply had lifted away in a part of the cockpit area and the right hand rear side.  Also during preparations to fix this I tripped while climbing onto the hovercraft and punched a hole into the decking about 100mm in diameter with my knee.  The knee repaired itself but I had to fix the hovercraft.

My plan was to drill small holes through the deck ply and inject epoxy into the space between the foam and the ply.  This plan worked well and both areas and the hole caused by knee were completely repaired.  The deck was then painted and a rubber decking material installed to look better and to allow passengers to climb in and out of the craft and have somewhere to step on.

IMG 5337

Rear Duct Strut Damage – July 2016

When taking the craft out for a test run the read duct strut was broken when it hit a low fence next to the boat ramp.  I had lifted the craft too close to the fence to avoid all the traffic but the boat ramp was crowned and the craft simply slipped downhill and hit the fence.  Fortunately the strut split rather than break.  This allowed the strut to be epoxied and clamped together.  It repaired well, had to be repainted and new decals applied.

 IMG 5361

 Engine Problems at 8 hours.

The craft ran perfectly for 8 hours and then the next cruise the engine started to backfire and loose power after 30 mins of running.  This problem persisted and the craft had to be towed to the boat ramp.

The engine was serviced and all the sensors checked.  A new fuel pump was installed to overcome a slow first start as the original fuel pump appears not to have a non return valve.  On testing the engine ran well.

To assist in maintaining the engine, the wiring to allow the Subaru SSM troubleshooting codes to be read was installed.  A new exciter and ECU was installed just because the original equipment looked “well used”.  A test run to test the engine experienced one backfire but the engine did not loose power.  The troubleshooting codes showed a “13” that is a Cam angle sensor and this wiring will be checked.

During the investigation for the troubleshooting codes it was discovered that Subaru had a data connection on these early models.  There is a SSM serial connection.  Work is continuing to connect the Subaru computer fhrough the serial device and use a software package to have access to the ECU.

The cruise was also performed in strong winds and the landing on the boat ramp was not ideal and the rear of the craft hit a rock on side of the boat ramp.  This caused a hole in the body and the shock caused the propeller to come in contact with the thrust duct cutting a shallow hole.

 IMG 5508 

Damage to rear side of craft from rock – August 2016

To continue the saga the craft was test run in moderate winds.  When I came back in I did not line up the boat ramp early enough and when the craft entered the boat ramp the craft kept moving at an angle and the rear hit a rock next to the ramp.

IMG 5529 IMG 5523 IMG 5521

The damage is being fixed, the photos tell all.

  IMG 5544IMG 5545 IMG 5559

The repair replaced the damaged timber and fiberglass and epoxy both in place.  The void was then be filled using a marine two pack polyurethane foam.  This foam is stronger than the original polystyrene.  The mixed foam was poured into the void and it expanded to just above the top.  I then cut away the top and left a small void to make it easier to install the top ply.  The process was to be simple.  I mixed the epoxy and coated the ply, I then mixed the foam, poured it in and closed off the hole with the ply.  The foam expanded a little more than the void volume and I had to hold the ply in place until the inital expansion reduced.  I was then able to place a stack of bricks on the ply to ensure the ply was bonded and in the correct position.  This is also how I held the ply against the foam when re-gluing the decking. 

IMG 5561 IMG 5565

The structural repairs are complete and it can now be smoothed and be painted, the black decking will be extended to cover this area and then back on the water.

The plan is to not damage the craft.  I believe I have been driving it like a car and not respecting that it is a plane.  I need to per-plan my flights a little better and make sure I line everything up well before time, especially boat ramps.

 

 

We're sorry, you must be logged into the website to post comments.

Author / Member : lazza

About Us

HOVERCRAFTER is a web-based community of enthusiasts discussing all things that are hovercraft related. If you're an experienced hovercrafter we'd appreciate your input. And if you're new, this is a great place to learn! Our goal is to create a place where the community can come together, build knowledge, and help one another become better hovercrafters.
We'd like YOU to join us! hovercraft,hovercraft kits,sevtec,universal hovercraft