Ariel Owners Motorcycle Club

This came my way recently. It's been carefully done with serious use in mind, and has been in dry storage (back of a garage) since the 1970s.
I do have the barrels and heads as well, and a siamesed exhaust.
And I do know what its intended use was, but I'll keep that secret for a bit!

SG

World's fastest lawnmower?

Kart as in Go-?

Generator??

Belt drive to a wood saw

Few more pics of details...

Drive side (as it used to be!), re-shaped end cover with counter-sunk set screws (for clearance to belts I guess) and very carefully removed chain adjuster lug (as compared to the only cover I've got with the usual broken adjuster lug )
Inside the chaincase (as was, should probably now call it a pulley cover with points!) - pretty carefully machined to get more clearance for the pulleys, looks like it might even still accommodate an oil seal even though that's now surplus to requirements.
The lug for the adjuster-access plug has also been very carefully removed.
On the other side (alternator side, as was), the end cover has again been carefully modified to get more clearance - alternator mounting lugs removed and a couple of 'low profile' countersunk set screws.
Note security wiring - and does anyone know the proper way to get one of those things off? (Clearly a nut of some kind.) Standard end cover coming up in next post for comparison....

SG

Standard alternator-side end cover: Finally, the mounting for the toggle-start (is that what you call it?) is the original steel alternator outer cover, cut away for the belts, and with reinforcing ribs pop-riveted on (note the original cover drain hole under one of the ribs - only now it's at the top!) .
It was originally in a late-ish 'B' Leader, and came with what is probably the original 375 carb and not the 376 for the Sports Arrow which would probably fit straight on and give an extra couple of bhp, so I'm guessing that everything's still in standard tune. (Running the siamesed exhaust system that came with it maybe wouldn't do much for the tune anyway - comments from knowledgeable Leader/Arrow folk gratefully received!)

And what was it for? A hovercraft, apparently - lots of pulleys for running lots of fans!
Co-incidentally there's a guy in the local VMCC who used to do hovercraft racing. This engine has been so nicely done (to my eyes anyway) that I'm half-tempted to get it back to running as it is. Not sure how good it would be in its new application, from what I've been told much lighter and much much more powerful units have been available for some time - maybe this one got made redundant quite early in its new career.

Interesting though, I think.

SG

Great to see that this engine has survived. Chopped Arrow engines were indeed used on Hovercrafts,( the Arrow engine was also used in Go-Karts). Here's an article that appeared in Motor Cycle in December 66 of a Hovercraft on test at Mallorty Park with chopped Arrow engine on the front and a Velocette Viceroy engine on the back. Jess

Well, Jess - that gives me some thinking!
Both the engines in that Clark hovercraft drive a propeller directly - no belts or pulleys. Also, it seems very likely that a hovercraft needs two independent engines, it wouldn't seem to be very useful having the 'lift' power varying in step with the 'go' power, as it would if there was only one engine being used. This engine was donated to a hovercraft project as a suitable power plant but maybe it didn't come from a hovercraft originally, and maybe they didn't progress far enough to realise that they actually needed two engines.
I've trawled the net for go-kart info, the only Ariel-powered ones I can find use the clutch and gearbox - but also all the karts seem to be driven from one wheel only. Four pulleys would work for a four-wheel drive but I don't think any kart guys went that far! (Although, four-wheel drive might be useful for the world's fastest lawnmower...)
We've had an 'Ariel on water' at an Annual, I was thinking it would be nice to do an 'Ariel on air' as well. ('Club hovercraft' as well as 'club veteran'?) More research needed!
(However, another article for the online Library!!)

SG

Some years ago I bought a basket case 1940 VA (500cc side valve) from an Australian who had brought it with him after marrying a Norfolk lass and moving to the UK. He told me that when he was a scout troop leader they were trying to build a hovercraft and were going to use the VA engine to power it!! Given that the VA struggles to pull itself along, let alone a rider as well I don't think that there would be any grunt left to lift a hovercraft into the air.