Plasma “Ghosts” May Help Keep Future Aircraft Safe

Air-to-air combat or “dogfighting” was once a very personal affair. Pilots of the First and Second World War had to get so close to land a hit with their guns that it wasn’t uncommon for altercations to end in a mid-air collision. But by the 1960s, guided missile technology had advanced to the point that a fighter could lock onto an enemy aircraft and fire before the target even came into visual range. The skill and experience of a pilot was no longer enough to guarantee the outcome of an engagement, and a new arms race was born.

An F-15 launching flare countermeasures.

Naturally, the move to guided weapons triggered the development of defensive countermeasures that could confuse them. If the missile is guided by radar, the target aircraft can eject a cloud of metallic strips known as chaff to overwhelm its targeting system. Heat-seeking missiles can be thrown off with a flare that burns hotter than the aircraft’s engine exhaust. Both techniques are simple, reliable, and have remained effective after more than a half-century of guided missile development.

But they aren’t perfect. The biggest problem is that both chaff and flares are a finite resource: once the aircraft has expended its stock, it’s left defenseless. They also only work for a limited amount of time, which makes timing their deployment absolutely critical. Automated dispensers can help ensure that the countermeasures are used as efficiently as possible, but sustained enemy fire could still deplete the aircraft’s defensive systems if given enough time.

In an effort to develop the ultimate in defensive countermeasures, the United States Navy has been working on a system that can project decoy aircraft in mid-air. Referred to as “Ghosts” in the recently published patent, several of these phantom aircraft could be generated for as long as the system has electrical power. History tells us that the proliferation of this technology will inevitably lead to the development of an even more sensitive guided missile, but in the meantime, it could give American aircraft a considerable advantage in any potential air-to-air engagements.

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Lighting Fires With Lemons

We all know that you can stick copper and zinc in an acid and make a battery. And the classic demonstration of this is with a lemon. YouTuber [NorthSurvival] takes this to an extreme — starting a fire by shorting his lemon battery across some steel wool. (Video embedded below.)

Now calling this a “survival tip” is pushing it. A lot. When’s the last time you went camping with a bunch of zinc and copper nails, much less a supply of fresh lemons? It might be easier to put some matches in a waterproof canister, or just bring a lighter. But when the zombie apocalypse comes, and all the lighters are used up, the man with a lemon tree will be a millionaire.

Seriously, though, this demo made us question a few assumptions. First, when people do the potato- or lemon-battery experiment, they often use multiple lemons. Why? Hooking the pins up like [NorthSurvival] did in series seems like a no-brainer after the fact.

And the lemon seems to be putting out a fair amount of juice (Amperes, that is). We’ve got to wonder — what is the short-circuit current of a lemon battery? And why haven’t we seen specs anywhere? What kind of “science education” experiment is this anyway, without measurements?

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You Know That They Say About Guys With Big Lenses?

[Tony Lovell] and [dkpeterborough] built a sizable camera lens using optics from a flight simulator projector. What they ended up with is a 900mm lens that can make a beautiful photo of the moon, or capture distant landscapes in great detail. The body of the lens was designed in CAD and sent off for fabrication out of aluminum, as seen above. The concentric baffles help to prevent lens flare but it can’t be used in its bare-aluminum condition. The internals were coated using a stippling finish that leaves a sandy texture. That was covered with matte black barbecue paint, doing a great job of preventing optical interference, and the outside received a glossy white coat. Finished weight: 59 pounds, but once you see the pictures you’ll agree it’s worth lugging the bulky instrument around to grab that killer shot.

[via Make]