April 2004

The first race of the season was now only a couple of weeks away - the 17th April at Wicksteed Park. Realisticly I wasn't going to get it finished, but I didn't want to miss too many more races. There was still a lot of work to do to get the hovercraft finished.  I still hadn't started the engine, let alone got the thing hovering. The second race of the year would be at Jakes Place on the 1st May and then there was Gang Warily on 29th May.

I needed a get-me-going plan, so decided to:

Fit the duct and fan frame
Weld up the bracing struts from the fan frame to the cockpit frame
Fit the engine frame to the floor
Wire up the CDI
Make a steering system - handlebars and cables
Make a throttle control - cables
Fit the fuel system components
Remove the flywheel, and fit the starter cup.
Fit the exhausts as simply as possible.
Forget the power valve controller for the moment - I can always do that later.
Fit the skirt
Fire up the engine
Hope for the best!

While visiting the OAPs in South Wales we went to ABC camping and bought a huuuuuge tunnel tent - big enough for the family and the hovercraft.

More storage problems
So far, due to lack of storage, I had been building the hovercraft components separately, and rarely bringing them together. But now they all need to be bolted together for the final build, and the whole craft needs to be stored, so the garage needs a real sort out. My mate Paul came round and we moved the lifting beam a few feet, so that the complete hovercraft can be suspended over the bonnet of the old landrover via a girder trolley and 1 ton chain lift. As the ex-army trailer hasn't been used since the day I brought the TZRs back in it, that went off to be sold - a sad day indeed.
With the hovercraft suspended above the landrover bonnet (it doesn't touch), I can store it fully assembled. 

Never mind. I reassembled the engine unit, transmission, duct and splitter box onto the hull, with the aim of getting a whole hovercraft up and running..

Bracing struts
If you think about it, the thrust from the fan pushes the hovercraft along by pushing the fan frame forward, and as this is bolted to the duct and floor of the hull the whole craft is pushed forward. The point of effect of the thrust is at the centre of the duct, about 45cm above the deck of the hull, so to give it a bit more rigidity, I added a couple of struts running from the fan frame, through the duct guard and down to the cockpit frame. These aluminium struts locate onto steel stubs which I welded onto the front of the fan frame.
The stubs on the fan frame locate the ends of the aluminium tubes.

The fan frame then looked finished, so we (me and Evans Junior) painted it with Smootherite

Splitter plate
The splitter plate diverts around 1/3 or 1/4 of the air from the fan down into the hull chambers where it emerges into the skirt to produce the all important lift to make the craft hover. As the engine (and fan speed) varies, the amount of air pushed into the skirt will also vary, but the air flow to the skirt should remain roughly constant. So how much air should I split off ? I don't know, but by making the splitter plate adjustable I can try out various settings. One day I hope to make the splitter height electrically controllable from the driver's position, or, even better, make it automatic, so that the splitter height varies according to engine revs (or maybe cushion pressure).

The splitter plate was formed on the sheet metal bender from a piece of 1.5mm aluminium size 1140mm x 250mm. I bent the leading edge over to give it some rigidity and bent the sides round to 90 degrees, to help trap the air. The rear of the splitter plate was then attached to the splitter box via a piano hinge, which allows the front to move up and down.
Don't waste your time - get a proper flywheel puller.

Flywheel problems
I bought two TZR engines in April last year. The one that I stripped early-on had no alternator, and the flywheel came off no-problem. The second engine was the one that had been on the working bike, so I was hoping to use that one in the hovercraft. This flywheel was a real pig to remove. I didn't have a proper screw-in flywheel remover, but I did have a 3-legged so called "universal" puller, so I decided to grind the ends of the legs down to fit into the three holes in the flywheel. Half an hour of grinding and I had a tool that looked like it would do the job - but looks can be deceptive. It wouldn't grip the flywheel well enough and all that happened was that I chewed the flywheel a bit more. I decided to forget it and buy the proper tool. I phoned Beedspeed and bought their flywheel puller (part number 16555 costing £4.99). Within 24 hours the parcel had arrived and I was back in business. I screwed the puller into the flywheel centre (after spotting that it was a left handed thread) slapped some grease on the puller bolt and screwed it home. The flywheel popped off cleanly. So why didn't I just buy the proper tool from the start? Oh, you know...

Wicksteed Park
The first event of the season came around, and sure enough I wasn't ready, but we went along anyway. It's strange meeting people you have only "met" via the internet - websites/bulletin boards etc. I didn't want to turn up at my first race and fail the scrutineering, so I had a chat with chief scrutineer Tony Shepheard. He introduced me to scrutineer Tony Drake who said that he was happy to look at my hovercraft between events, if I could bring it to him.


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