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The Helicopter with Radioactive Blades

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11–20 of 68 posts

Re: The Helicopter with Radioactive Blades

#11
post #4

Often in software development I encounter code that seems overly complex. It's not always obvious at first glance whether that complexity is because it's solving a really difficult problem, or because the developers made it more complex than it needed to be. Having no domain knowledge of the problems of detecting cracks in blades, this sounds like either a genius solution to a super hard problem, or unnecessary compl…

Chesterton's Fence

Re: The Helicopter with Radioactive Blades

#12
post #4

Often in software development I encounter code that seems overly complex. It's not always obvious at first glance whether that complexity is because it's solving a really difficult problem, or because the developers made it more complex than it needed to be. Having no domain knowledge of the problems of detecting cracks in blades, this sounds like either a genius solution to a super hard problem, or unnecessary compl…

Given the forces involved, the need to avoid wireless communication, the complexity of any bearing with associated electrical contact, and so on this seems like the least complicated solution. You can rely on radioactive elements to emit radioactivity above background, you can build a pretty reliable pressure indicator, and you can fill a cavity in the blades with gas pretty reliably. You sidestep all of the complicated mechanical linkages in favor of a solution that's not in the rotor hub at all.

Re: The Helicopter with Radioactive Blades

#13
post #4

Often in software development I encounter code that seems overly complex. It's not always obvious at first glance whether that complexity is because it's solving a really difficult problem, or because the developers made it more complex than it needed to be. Having no domain knowledge of the problems of detecting cracks in blades, this sounds like either a genius solution to a super hard problem, or unnecessary compl…

I though it sounded pretty clever. Now, that can be good or bad depending on context. I mean it in a good way. It seems simple conceptually (I have no idea if it adds a lot of complexity to the manufacturing) and rather foolproof. I guess the radiation shield could jam and not move when it should.

Re: The Helicopter with Radioactive Blades

#14
post #3

What if the helicopter would have to operate in a contaminated area? Wouldn't it cause false positives? > The CH-53 Sea Stallion first entered service in 1966 1966 is Cold War era, so, I think, an idea that a military helicopter would have to fly in an area that has been recently nuked wasn't totally inconceivable...

Strontium-90 is a beta emitter, apparently, so you could just measure Alpha, Beta, and Gamma and detect false positives due to elevated background radiation that way. If you're in the air you're probably much closer to your Beta source as well so you could detect it above background due to distance. Gamma is essentially light so it falls off with the square of distance. But Alpha and Beta are probably much worse than Gamma in that respect, so I'm guessing this is fine most of the time and then they rule out false positives by looking at the total background in each type of radiation.

Re: The Helicopter with Radioactive Blades

#15
post #3

What if the helicopter would have to operate in a contaminated area? Wouldn't it cause false positives? > The CH-53 Sea Stallion first entered service in 1966 1966 is Cold War era, so, I think, an idea that a military helicopter would have to fly in an area that has been recently nuked wasn't totally inconceivable...

Assuming only one rotor cracks, then the radiation is from one rotor IBIS and the detector electronics could detect radiation levels that ripple synchronously with the rotor speed.

The Strontium-90 is a beta radiation emitter.

  The external radiation level of the IBIS [is] 75 mR/hr at 12 inches in the failure (extended) mode.

Re: The Helicopter with Radioactive Blades

#16
post #8

Earlier quoted context omitted.

Exposure to a nuclear blast doesn't necessarily make things radioactive. Hiroshima and Nagasaki are not radioactive wastelands. Even in Chernobyl, the other reactors continued to operate for a time after the accident, and nature is thriving. But, the radiation detector is on the upper surface of the rear fuselage. Hypothetical Beta particles from the ground will strike the underside of the aircraft and not the detect…

> Exposure to a nuclear blast doesn't necessarily make things radioactive Isn’t this neutron activation?

It is, but a) it's a probabilistic process and b) most of the products decay rapidly, down to the background level in a matter of days.

Re: The Helicopter with Radioactive Blades

#17
Some really hyperbolic comments on there:

JohnU says: "It’s all fun and games until helicopter crashes and what should be a minor incident turns into a nuclear emergency where you have to call very specialized decontamination units to remove radioactive material from the site."

Alan Reid says: "unless they shoot ’em down on your own territory

then you don’t have a helicopter but you have mini-hiroshima to clean up."

How much Strontium-90 do they think these things are carrying?

Do they have smoke detectors at home (I hope so...)?

Re: The Helicopter with Radioactive Blades

#18

Terrible explanation

Hackaday isn't the end-all, be-all authoritative source for anything. It's a blog that, for the most part, links to neat stuff with a summary write-up. If something interests you then it's on you to follow the links.

This is how the web used to work.

Re: The Helicopter with Radioactive Blades

#19

Some really hyperbolic comments on there: JohnU says: "It’s all fun and games until helicopter crashes and what should be a minor incident turns into a nuclear emergency where you have to call very specialized decontamination units to remove radioactive material from the site." Alan Reid says: "unless they shoot ’em down on your own territory then you don’t have a helicopter but you have mini-hiroshima to clean up."…

You must not hang out on there. Those are some pretty standard grade Hackaday comments. I love the site, read every day, but the comments section can be... rough.

Re: The Helicopter with Radioactive Blades

#20
post #2

The article is very vague on how the radioactivity allows detection of leaking gas. The video at the bottom explains from 7:50 in. Gas pressure pressing on a spring holds a radiation shield in place. If the gas leaks the shield moves and the radiation can be detected.

The titanium spar is filled with gas. If there was a crack in the spar the gas would escape, therefore tripping the pressure sensitive radiation shield. Releasing radiation that can be detected inside the helicopter. Wireless systems aren’t used for opsec reasons.

Wireless arent used because they need power/wires and are less reliable than IBIS. Civilian versions of sikorsky helos use the same system.
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