Hovercraft - what happened to them?

[zenrat]

Now i'm thinking about hovercraft wall of death.

And now, if a car could generate enough downforce that it could drive on the roof of a tunnel...

[PR19_Kit]

And now, if a car could generate enough downforce that it could drive on the roof of a tunnel...

They've done that with large scale models of F1 cars in wind tunnels.

Darned if I'd like to have been the guy who DIDN'T catch it when they turned the wind off! 

[zenrat]

And now, if a car could generate enough downforce that it could drive on the roof of a tunnel...

They've done that with large scale models of F1 cars in wind tunnels.

Darned if I'd like to have been the guy who DIDN'T catch it when they turned the wind off! 

Time for a full size test then.  We need a volunteer...

[steelpillow]

The point of banking with wheeled vehicles is to redirect some of the cornering forces down through the tires to increase grip, thereby countering the rest of the cornering forces that are trying to push the vehicle sideways to the outside edge of the track.

Up to a point. Or, the driver can just run higher up the banking until gravity balances the sideways component of centrifugal force, and then put their foot down cos the tyre grip can then be used to go faster still.

The tendency of a hovercraft to fall down the slope towards the middle of the turn under gravity counteracts the cornering force trying to push it up the slope towards the outside

Exactly that. No maths required, just set your line for zero side thrust and hence max forward thrust.

The maths is above my pay grade, so I don't know what that does to the necessary geometry of the track, but I'll bet a small amount of money that it'd need to be different from a standard car racing track.

No fundamental difference, though you wouldn't want your hovercraft to be much wider than the cars the track was designed for.

Then again, would you even need to do that? When you watch hovercraft racing ... they turn in a huge "skid"

Need? NEED??!!! Whose side are you on anyway?
I just want to see sparks flying out from under their rubbing strips/skirts when they ground at high gee.

[NARSES2]

I can remember one of the Grammar schools in Croydon bulding a hovercraft for science some time in the early 60's. Fascinating, if noisy and difficult to control thing.

[seadude]

I still think that racing hovercraft round a track with banked corners would be fun. Brooklands, Monza, Sitges-Terramar, Indianapolis - a fine racing season.

Talk about not grounding the suspension!

Racing? How about this? 

[jcf]

Dr. Bertelsen in the US worked on his own concept of a Ground Effect Machine for many
years separately from Cockerell. His concept was quite a but different and his motivation
was to make a vehicle that could reach his patients in otherwise inaccessible areas.
Later he worked on tracked guideway notions, some more sci-fi than others including,
as shown in the artist's rendering, automated so you could call the vehicle to come get
you. The most relatively practical was a semi-skirted design matched to a concave
guideway.

I suppose you could use something like that as a basis for a racing hovercraft and track.
Long, wide open straightaways leading into 5 or 6 separate guideways at the curves.
The racers jockeying for position on the straightaways to grab the smallest radius
guideway at the curve. 


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[steelpillow]

That's really cool!  Is there an online resource worth checking out for more about Bertelsen's hover thingies?

I still have a book from my childhood: William Mayne, "The Changeling", Oxford University Press, 1961, in which a bunch of kids unearth an old hovercraft in the back shed of a decrepit old gentleman who had lost his memory. That really puts the date of of Mayne's imagined development back a few years, maybe even prewar. I have often wondered at the historical facts behind that imagination.

[Rheged]

How many of us have actually ridden in a hovercraft?  I know Kit has been deafened by an SRN4,  as was I on 21st December 1986.  Bridget and I were married on 19th, travelled to London on the next day and  set off on honeymoon for France on 21st.  It was a very rough, noisy crossing!!   It was a lot smoother  eight days later on our return. I've also flown/sailed on SRN5 and 6.................and on a real oddity, the Denny D2-001!

https://www.facebook.com/groups/hovercraftmuseum/posts/10161018850431979/

[PR19_Kit]

I've been lucky enough to travel in ALL the SRN series apart from the very first one, rather obviously as it wasn't designed for carrying paying passengers.

Hovertravel ran both the SRN2 and the MASSIVE SRN3 in trials service on their Isle of Wight roues during the 60s, and with a bit of 'inside info' I managed to ride in them both. And of course the more commercial SRN5s and 6s they used later on that route later on.

And in recent years I've ridden (Flown?) aboard the current generation of hovercraft used on the IoW route too.

As for the SRN4, I know it intimately, having spent two days going back and forth to Boulougne taking oil samples while cowering in the VERY NOISY APU bay in the stern!
And I have travelled as a passenger with my car aboard a 4 as well, quite few times.

[PFJN]

Hi,
I spent roughly the better part of two weeks assisting in trails of one of the South Korean LSF-II LCAC's many years ago, and I also took a short trip on a USN LCAC as well.  Though for the most part I was in either the mostly windowless port side troop cabin (for the USN craft) or the windowless lower level of the Starboard side crew cabin (for the Korean craft) so I never saw much.  In alot of respects it kind of reminded me of flying on a noisy turboprop commuter plane with the added benefit of the realization that if the craft had any engine problems we hopefully wouldn't fall very far  .  On the flip side though, while on the Korean craft they had a tank on deck so there was always the nagging thought in the back of my mind that if the tiedowns failed and the tank came loose I'd be in a hopeless situation, but hopefully it would happen do quickly that I may not notices. 

[steelpillow]

Been across the Channel a couple of times, once with Dad and his car, once as backpacker. Far too excited to worry about bumpy bits (unlike poor Mum).

[PR19_Kit]

How does a Korean LSF-II LCAC differ from the USN version? It looks pretty much identical in the pics.

[PFJN]

Hi,
For the most part they were very similar.  The biggest difference as I recall were the "bow thrusters" above the main fans.  On the original USN LCACs they had a single "Macaroni Noodle" type shape on each side, while on the Korean LSF II they had a rotating grate like shape over each fan on each side, as shown below.


[The Bow Thrusters are the items with the 55mph Speed Limit printed on them]


[The Bow Thrusters are the round "striped looking" things above the fans on each side]

The "stripes" are because the grates are stepped like shown below.

[PR19_Kit]

Ah yes, thanks for that.