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Old 06-30-2021, 08:41 PM   #11 (permalink)
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The other problem with airships is that they are far too affected by the weather. The US lost a number of airships between the two world wars to weather events. (Three major ones that I can think of: Akron, Macon, and Shenendoah.) They're large enough to be severely affected by a good thunderstorm, and not fast or high enough to get out of the way of such a storm.

That's in addition to the PR nightmare that the Hindenburg disaster imprinted in the public's minds.


As for helicopters, last I checked they were not very fuel efficient, when compared to fixed-wing aircraft, which in turn are not very efficient when compared to ground vehicles.

The Tiltrotor (V-22 above, and the "upcoming, someday, maybe" Bell 609) were developed in large part because they were more fuel efficient in cruise than a helicopter, as well as faster.

-soD

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Old 06-30-2021, 08:55 PM   #12 (permalink)
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Helicopters and autogyros are less fuel efficient. But a well built autogyro (also airship) has the advantage over a fixed wing aircraft of not being able to stall.

Airships have the potential of being more fuel efficient. But I guess there are fixed wing aircraft that are pretty fuel efficient too.

My dream aircraft would be an airship covered in lightweight solar cells.
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Old 07-01-2021, 01:33 AM   #13 (permalink)
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Yeah, but there's no point in fuel efficiency when we're talking about a snail's pace, unless it can be scaled up so huge that bulk shipping can be efficiently accomplished. Totally pointless for human travel.

I was excited for the coaxial helicopter the Russians were developing. Conventional helicopters are something like 30% less efficient than fixed wing, and coaxial reduces that somewhat due to cancelling the need for a tail rotor.
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Old 07-01-2021, 03:04 AM   #14 (permalink)
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Quote:
Originally Posted by redpoint5
I just don't know why the helicopter isn't favored?
Have you ever been around them? They're loud. From my experience the Hughes 500 'Loach' was like a mosquito up in you ear, but the Sky Crane was HARD TO IGNORE.

My ideal would be the Aeromodeller2.
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Originally Posted by DDG
Aeromodeller2
aeromodeller2.be
The Aeromodeller2 is a design for a zero-emission, autonomous, nomad hydrogen-based airship that will never land. The ship regenerates its fuel, creating hydrogen from wind power and the rain on its skin. When it depletes its energy reserves, the ship drops anchor and rests, in order to replenish its energy in a renewable way.

https://i.pinimg.com/originals/65/0d...b2d5576bbc.jpg

It's got that triangular shark-body shape like the ME-262.
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Old 07-01-2021, 01:05 PM   #15 (permalink)
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Quote:
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Have you ever been around them?
Driving into Boise earlier this year a medical helicopter was landing very near to the freeway I was driving. I was perhaps 200 ft from it and wouldn't have known it was there had I not seen it. Apparently it was quieter than the road noise at that distance and position.

I'm not advocating for Hueys, but normal helicopters that already operate in cities.

EDIT: I might advocate for Hueys because they sound awesome, but then I don't want to trigger PTSD.
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Old 07-01-2021, 01:33 PM   #16 (permalink)
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Hueys pair well with 60s rock.

My son told me about the moment after the Bin Laden raid that he suddenly realized that black helicopters were real.
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Old 07-01-2021, 01:37 PM   #17 (permalink)
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Quote:
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My son told me about the moment after the Bin Laden raid that he suddenly realized that black helicopters were real.
... and apparently need to be burned after use.
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Old 07-04-2021, 03:49 PM   #18 (permalink)
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Only if they are likely to fall into the wrong hands. (I.e., anyone but their operators.)

There have been coaxial helicopters as well as various twin-rotor types over the years. Some of them had very closely-located intermeshing rotors, others had a rotor on each end of one on each side.

I'm guessing that the reason we don't have many today is more than just economics... But it is just a guess.


Like I said earlier, the airship thing is a great idea. A neutral-buoyancy craft doesn't have to fight gravity. But to get to neutral buoyancy, most craft will have to be large enough that severe weather is a severe problem.

References for my earlier statement about the airships lost to weather:
https://en.wikipedia.org/wiki/USS_Akron
https://en.wikipedia.org/wiki/USS_Macon_(ZRS-5)
https://en.wikipedia.org/wiki/USS_Shenandoah_(ZR-1)

It appears that the Navy used a grand total of five rigid airships. One was destroyed in testing aggressive maneuvers before delivery, and one actually survived until its decommissioning. The other three were lost above. Not a very good record...

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Old 07-04-2021, 05:28 PM   #19 (permalink)
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I've had this tab open for days. Now I know why.


http://www.hisutton.com/images/Fr_G20_Prototype.jpg

I thought it was for that landing gear.

The airships needed higher power/volume ratio and more rigidity. The optimal aeroform can have it's back broken. The smallest volume would be acquired with a hot Hydrogen partial vacuum. It could be surrounded by a thermal/electrical insulating blanket of Helium or steam. Rigidity could be acquired with a tensegrity geodesic structure. That might look like this:



This is an externally braced icosahedron for clarity. Higher frequencies would have a quasi-compound curve.
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Old 07-05-2021, 07:02 AM   #20 (permalink)
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There was a time when I was obsessed with the aerocar. And I looked into the practicalities of owning one.

Airside vehicle passes cost between £50 and 150 in the UK and depending on airport takeoff and landing can cost between £10-30. Pre-flight checks take between 15-45 minutes, taxi time 5-15 minutes.

While I think this idea is really cool, it is only really worth it from certain perspectives. Beat the traffic, well only if you spend an hour in the traffic. Save time, same argument, save fuel, definitely not.

If you have enough money and a long enough commute to buy one and for it to be worth it, you can probably afford afford a house nearer where you work.

I want one though, but definitely have no need for one.

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