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It's 60 years since the British inventor Christopher Cockerell demonstrated the principles of the hovercraft using a cat food tin and a vacuum cleaner. Great things were promised for this mode of transport, but it never really caught on. Why?
The hovercraft slides down a concrete ramp and into the Solent. Its engines, propellers and fans hum as it crosses from Southsea, in Hampshire, to Ryde, on the Isle of Wight, travelling 4.4 nautical miles in under 10 minutes.
The journey is more than twice as quick as the catamaran from Portsmouth to Ryde and more than four times as quick as the Portsmouth-to-Fishbourne ferry.
For that matter, why haven't hydrofoils caught on?
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What Happened to Passenger Hovercraft?
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A well adjusted person is one who makes the same mistake twice without
getting nervous.
(Score: 4, Insightful) by VLM on Wednesday November 11 2015, @02:07PM
Non engineers always dramatically underestimate how much it costs (both financial and energy) to move large amounts of air. Always, across all fields.
So "float off the surface using a big fan" is always going to sound cheap and simple and reasonable to non engineers while the engineers all WTF right back at them. You'll note the supporters are universally MBAs and liberal arts marketing people, the only love they get from engineers is a grudging "holy shit, they actually got this thing to work" amazement.
Its not just capex but opex and the costs of crazy operational constraints to make sure you don't suck passengers and pedestrians thru the fans and expensive safety solutions all over the place and the fan has to survive eating like one seagull per trip which ends up being non-trivial expense, and what happens when the fan swallows a freak ocean wave while operating, blah blah blah. The overall lifetime expense is so crazy expensive its impractical long term for all but US marine beach storming vehicles and stuff like that. You could argue its not practical long term for the US Marines to storm beaches, for that matter.
(Score: 4, Funny) by snick on Wednesday November 11 2015, @02:21PM
How expensive could a seagull be? Would it be cheaper if they used chickens?
(Score: 2) by VLM on Wednesday November 11 2015, @02:53PM
Its the shock to the axle and the geartrain (assuming a gas turbine) and the individual fan vanes themselves. Also the eco hippies are going to whine about seagulls being an endangered species. And mothers of traumatized passenger kids watching seagulls get vaporized.
Oh I assure you, I can design a machine that sucks in air and seagulls and blows out air and a pink mist, thats called a "garden chipper shredder" but the fuel consumption to levitate something like that into the air while carrying a payload is going to make SUVs and bizjets look like greenwashing products. Also its going to be expensive and maintenance intensive. Its a miracle that its actually technically possible at all.
Seagulls are actually pretty expensive to deal with. I wasn't kidding about the endangered species thing. There will be protests and EPA costs, not to mention PR. It'll be pretty expensive as a total system cost.
(Score: 2) by bob_super on Wednesday November 11 2015, @04:34PM
> is going to make SUVs and bizjets look like greenwashing products.
Well, there's your market!
So, which Texan star or billionaire are we going to offer the blingest hovercraft in history to, in order to jumpstart interest?
"Bubba says F-You to Obama and the EPA with a hovercraft from RollingCoalIsForThePoor.com. Why are you still driving a puny Escalade?"
(Score: 0) by Anonymous Coward on Wednesday November 11 2015, @04:38PM
It is like the IoT home systems. Sure they are cool and are all wizzy. But simplicity, ease of use, and cost rule the day. Sure I could hook every single one of my lights in my house to a central computer. It looks cool and is cool. But thats about it. At the end of the day it still just lights up my room and a rocker switch on the wall works just as good and does not come with a service contract.
It is a technical challenge to be sure. But why, when you end up with pretty much the exact same thing which can be had cheaper? I see this sort of thing all the time in software. People throw out years of coding. Because 'its a mess' (translation I dont understand it and am not going to take time to understand it). Total rewrite is undertaken and they end up with either the same thing or worse but slightly technically better.
If you dont beat the cost (both short and long term) of the simpler solution you will not go anywhere with it. Hovercraft are in the realm of 'cool and wizzy' and have specific places where they can be used. But they have to beat a big tub with a propeller.
(Score: 1, Insightful) by Anonymous Coward on Wednesday November 11 2015, @04:39PM
Hey VLM, that whooshing noise you just heard wasn't the sound of a hovercraft.
(Score: 2) by VLM on Wednesday November 11 2015, @05:27PM
Yeah yeah I know but there's just so many ways the task is incredibly expensive I couldn't resist the chance to mention the bird kill problem and the difficulty of making turbines that eat large birds and keep running (like jet aircraft engines, well, at least sometimes) and chipper shredder analogies and ...
Its just so roadrunner cartoon, sign up for the ACME air fan and it just works, but really moving enormous amounts of air is just a PITA engineering challenge.
(Score: 2) by Freeman on Wednesday November 11 2015, @06:02PM
Just make sure to thaw them first.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 2) by Phoenix666 on Wednesday November 11 2015, @03:41PM
Then why is it that 747s have won over zeppelins? It's much cheaper to generate lift by displacing air than moving air, so by your logic we ought to all be flying around in Hindenburgs.
Washington DC delenda est.
(Score: 2) by VLM on Wednesday November 11 2015, @04:33PM
It's much cheaper to generate lift by displacing air than moving air
Depressingly if you pull the actual numbers jets are about 10x cheaper. Zeppelin payload capacity was pitiful compared to a modern jetliner so when you think of the capex and opex and salary costs and fuel costs of a fleet of ten or more zeppelins vs one 747...
I'm not sure the cost of even one single zeppelin is cheaper than one single 747. Perhaps when I'm a billionaire I'll have my own private zeppelin to show off I'm wealthier than even the mere bizjet owners.
(Score: 3, Informative) by damnbunni on Wednesday November 11 2015, @07:55PM
A Boeing 747-8 has a list price of $367.8 million.
You can buy a new Zeppelin for about $21 million. That's what Goodyear is paying for their new Zeppelins; the Zeppelin NT is configured for 12-14 passengers and two pilots.
A typical 'bizjet' like the Cessna Citation X runs about $20-$25 million new, so oddly enough a Zeppelin NT is right in the same price range.
(Score: 2) by fnj on Thursday November 12 2015, @01:01AM
How about you finish comparing the apples to the oranges?
The productivity of the 747-8I is 410 passengers times 917 km/h, or 375,970 passenger-km/h, and the purchase price burden is just about $1000 per passenger-km/h. Actually, the figures for a single-class version are 50% higher. I don't think any carrier actually operates the single-class version, though they could if they could make a business case for it.
The productivity of the Zeppelin NT is 12 passengers times 87 km/hr, or 1044 passenger-km/hr, and the burden is about $21,000 per passenger-km/h.
The productivity of the Citation X is 12 passengers times 972 km/h, or 11,644 passenger-km/h, and the burden is about $1,900 per passenger-km/h.
You don't even see carriers using bizjets like the Citation X for paying service. It has twice the burden of the 747. Still less would you find anyone trying to use the Zeppelin for paying service, at 21 times the burden. Other costs, such as maintenance and insurance are in similar proportion. There is also the little problem that the Zeppelin's speed is so slow that its progress is slowed to half at the transition from a Beaufort fresh breeze to a strong breeze. At a strong gale it is literally standing still, and anything more than that pushes it backward. This is pretty moot, because I don't think it can land or take off in anything more than fresh breeze, or a low-end strong breeze at the utmost.
When the Zeppelin has been used for sightseeing (where it doesn't have to worry about schedule keeping), the seat charge has been in the hundreds of dollars per hour.
(Score: 2) by damnbunni on Thursday November 12 2015, @03:25AM
I was trying to address the 'I'm not sure the cost of even one single zeppelin is cheaper than one single 747.' part, not make the case that a Zeppelin is a better deal than a bizjet or 747.
As a filthy-rich toy, it's certainly cooler. Though if I had to choose between a Zeppelin and one of those submarine yachts, it'd be a tough choice.
(Score: 0) by Anonymous Coward on Wednesday November 11 2015, @10:10PM
Landing a dirigible on top of a tall building in Manhattan is cool.
Landing a jet there is not cool.
http://untappedcities.com/2013/05/28/daily-what-empire-state-building-zeppelin-docking-station/ [untappedcities.com]
(Score: 2) by fnj on Thursday November 12 2015, @01:08AM
No Zeppelin ever came close to mooring there, or ever could have. The air currents and proximity to obstacles are far too dangerous. There was also no provision for refueling or even ballasting. Any pictures you may have seen are staged science fiction.
(Score: 0) by Anonymous Coward on Thursday November 12 2015, @04:09AM
Right, the page I linked to, which I read before posting, says as much.