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Some ideas are just bad. Very, very bad. Like this blimp powered by 4 helicopters. [Info and vid inside] (thelemmy.club)
submitted 1 month ago* (last edited 1 month ago) by to c/chapotraphouse@hexbear.net
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The Piasecki PA-97 Helistat was an American experimental heavy-lift aircraft, built by Piasecki by fastening four H-34J helicopters to a framework beneath a helium-inflated blimp envelope. The sole prototype was destroyed during a test flight, killing a test pilot and injuring another four in the course of a single incident in 1986.

https://en.wikipedia.org/wiki/Piasecki_PA-97_Helistat

NSFW Video - https://www.youtube.com/watch?v=4KY3A2HlbzQ - it's barely off the ground when it crashes at ~1:00.

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[–] [S] 15 points 1 month ago (14 children)

I love this redditor's failed "Well actually..." attempt at defending the idea.

Hijacking the top comment since no one on this post looked up what this aircraft was for and as a result are just trying to dunk on it being a dumb idea.

This isn't a blimp. It's 4 helicopters using a blimp to cancel out their own weight in order to maximize heavy lift capacity. Its purpose was to be able to carry extremely heavy shit up mountains, which is something that a blimp, a single helicopter, or an airplane can't do.

From the wikipedia article:

The PA-97 was built under a 1980 U.S. Navy contract for the Forest Service to demonstrate a heavy vertical airlifter for harvesting timber from inaccessible terrain.

The best aircraft we have in this sector right now is probably the K-Max, and that lifts 1 or 2 logs at a time. You can make an argument for the Skycrane even though it isn't specifically made for logging. This thing was meant to lift an entire cabin's worth at once.

Also, someone lower down called out this accident being caused by a gust of wind - which is false. The aircraft dragged across the ground a bit due to the wind which created vibration from the landing gear, but the main brunt of the load that caused the structural failure was ground resonance, which effects ALL helicopters.

https://www.reddit.com/r/CatastrophicFailure/comments/v9romn/the_destruction_of_the_piasecki_pa97_helistat/ibz32xj/

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  • [–] 21 points 1 month ago (1 child)

    That last paragraph too oh my god

    the main brunt of the load that caused the structural failure was ground resonance, which effects ALL helicopters

    Yeah which makes it even more crazy that whoever built this monstrosity was allowed to do it. Anything that falls apart like that as soon as it's lifted has to involve skipping so much math to check forces there's just no way.

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  • [–] [S] 20 points 1 month ago

    I noticed that too. His "defense" and the crash itself reminds me of Richard Feynman's explanation about how cold weather impacted O-rings and caused the Challenger disaster. The crash coincidently also happened the same year.

    NASA officials said that the chance of failure of the shuttle was about 1 in 100,000; Feynman found that this number was actually closer to 1 in 100. He also learned that rubber used to seal the solid rocket booster joints using O-rings, failed to expand when the temperature was at or below 32 degrees F (0 degrees C). The temperature at the time of the Challenger liftoff was 32 degrees F.

    Feynman now believed that he had the solution, but to test it, he dropped a piece of the O-ring material, squeezed with a C-clamp to simulate the actual conditions of the shuttle, into a glass of ice water. Ice, of course, is 32 degrees F. At this point one needs to understand exactly what role the O-rings play in the solid rocket booster (SRB) joints. When the material in the SRB start to heat up, it expands and pushes against the sides of the SRB.

    If there is an opening in a joint in the SRB, the gas tries to escape through that opening (think of it like water in a tea kettle escaping through the spout.) This leak in the Challenger’s SRB was easily visible as a small flicker in a launch photo. This flicker turned into a flame and began heating the fuel tank, which then ruptured. When this happened, the fuel tank released liquid hydrogen into the atmosphere where it exploded.

    As Feynman explained, because the O-rings cannot expand in 32 degree weather, the gas finds gaps in the joints, which led to the explosion of the booster and then the shuttle itself.

    https://feynman.com/science/the-challenger-disaster/

    I don't see how four helicopters powering a blimp is in any way, shape, or form a sane idea.

    Rant. The Wikipedia page for the disaster is shit because it's missing that.

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  • [–] 15 points 1 month ago (6 children)

    something that a blimp, a single helicopter, or an airplane can't do.

    Build a train.

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  • [–] 11 points 1 month ago (5 children)

    TBH, building a rail track up the mountain is absurdly hard.

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  • [–] 7 points 1 month ago (4 children)

    Not just that, preemptively building a rail track up a mountain, in case we need to move something up that mountain at some later time.

    I stand by my absurd proposal.

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  • [–] 3 points 1 month ago (3 children)

    Railways demand very strict limits on the incline and the curvature of turns, which are the reason that tunnels are used so often, when railroads are built through mountains. And also you need to transport a lot of cargo, when building a railroad through mountains. Mountains are pretty much the worst case for railroads.

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