The Fastest Helicopter on Earth | Hacker News Reader

The Fastest Helicopter on Earth

spectrum.ieee.org

78 pointsgvb31 comments

While interesting, this is a puff piece written by the designers of the helicopter at Sikorsky.

Is it just me or the writing style of this article is really weird? It's as if different people have written different sections. Some of it sounds like a pre-flight briefing manual sans the helpful illustrations and other parts sound like a PR fluff piece. For example;

>>>But here's the catch. When a helicopter flies forward, the rotor blades experience a dramatic variation in airspeed. That's easy to see if you imagine a miniature version of yourself perched on the tip of a helicopter rotor blade. If the helicopter were hovering, you'd feel a constant 800-km/h wind in your face as the rotor spun around. If the helicopter were to fly forward, you would note that the wind was stronger on what's called the advancing side, when the rotor was moving in the same direction as the helicopter, but that it would be noticeably weaker when the rotor was on the retreating side. By the time the helicopter reached 150 km/h, you would feel a wind speed of 950 km/h on the advancing side, versus 650 km/h on the retreating side....<<<

I had to re-read this paragraph at least 2-3 times to understand what it exactly meant. It was just too vague. What direction should I face? Am I moving clockwise or counterclockwise? What does it mean that the rotor is moving in the same direction as the helicopter?

Then there was this paragraph, which sounds... fake considering the tone of the rest of the article.

>>>With everyone's nerves on edge, the X2 started up its engine at 6:30 a.m., and the helicopter took off. Within a few minutes the X2 had reached a speed of 350 km/h. A dozen people watched from the ground as the airspeed crept up, first to 400, then 410, and finally topping out at 435 km/h—not quite the goal we'd set, but good enough for this round. Cheers and applause broke out on the ground. The pilot slowed the X2, turned it around, and flew back to land on the runway.<<<

The same person who had trouble explaining the simple imagery of a rotating blade can't write something as flowery as that. It's just too unlikely.

I understood that paragraph without problems, and I'm not even a native English speaker.

I thought it was refreshing to read an article by somebody who was obviously involved - rather than just a puff piece written by a PR person who had never seen a helicopter

The first paragraph assumes you're facing the same way as the pilot - straight ahead. You do have to really build the image of the rotors in your head to follow the paragraph, but I have no complaints.

Both paragraphs were written by an engineer who's deeply involved on the technical side and emotionally connected to the team. Both paragraphs are consistent with their position, and the appropriate tones of voice from a single person in that situation.

While the Sikorsky X2 might have some niche uses rescue missions probably aren't one of them. It's tiny. A tiltrotor[1] aircraft like the V-22 Osprey seems a much better fit if you need to get there fast and do something meaningful like rescue work.

1. https://secure.wikimedia.org/wikipedia/en/wiki/Tiltrotor

The X2 is not a production model, it is an experimental aircraft. According to the article, the technology used in the X2 will eventually be used in production models that will presumably "go fast and do something meaningful." Otherwise nobody would buy them ;)

Well there's still plenty of uses for a fast and helicopter. Patrol missions for one. But hopefully they'll be able to scale this up to bigger sizes.

Does anyone know if that would be much harder? I.e. is it inherently harder to make heavier helicopters go faster? Or do you just have to scale up the fabrication.

I imagine like everything in aerospace, 'just scaling up' isn't as simple as it is. Drag increases non-linearly as you scale up for one thing, and with something as tricky as the rotors of helicopter, you probably have to do all sorts of nuts stuff to get it to work. For one thing, you can't just make the rotor span larger (with same rotation speed), cause then your increasing the velocity of the rotor tips which could cause all sorts of problems.

Anyone know of a decent biography of Igor Sikorsky? Most of the ones I'm finding on Amazon are either fluff or kids books.

The article really should have mentioned the BA-609 tiltrotor aircraft. It's the civilian version of the V-22, and nearly ready for production.

The BA-609, with the speed and range of an airplane, has tremendous potential, and is the reason why Sikorsky started resealching faster helicopters.

It's in the little slideshow dealy.

The V-22 should make for a very interesting engineering story when all of the history comes out. Tiltrotors inherently have a lot of moving parts, plus a very complicated aerodynamic profile as they transition from helicopter mode to airplane mode. It took decades to develop it, at least one fatal accident, and a lot of technology risk throughout, and all the while it was a prime candidate for cancellation. The only thing that saved it was its suitability for the Marine Corps, who needed an aircraft that could carry more Marines a longer distance than helicopters. (http://en.wikipedia.org/wiki/File:MV-22B_combat_radius_in_Ir...)

It's probably not too far from the truth to say that, just like stealth aircraft, we wouldn't have usable production tiltrotor aircraft today if it wasn't for the political tendency to spend vast amounts of money on unnecessary and implausible military contracts. Not an argument either way, just an observation.

To be fair, initial stealth technology wasn't even THAT expensive. The initial development of 'true' stealth (Pave Blue/F-117) cost about 2 Billion USD in R&D and a total of about 7 Billion for all the planes and everything else.

Furthermore, it wasn't even that implausible. Some Soviet physicist already wrote the paper telling us how to calculate Radar Cross Sections. The initial prototyping was a huge success (pretty much matched up exactly what their expected/calculated values).

Now, the B2. That's a different story. It's very hard to justify 2 Billion dollar bombers, no matter how you spin it.

Linkie here: http://www.ausairpower.net/Profile-F-117A.html and also Ben Rich's excellent (though somewhat biased) book Skunk Works.

The 2 billion dollar price tag is misleading, though--the design cost was supposed to be amortized over a much larger order of planes.

Everyone knows Airwolf is faster.

Truely: Airwolf's conventional top speed is 560 km/h compared to the X2's 435 km/h. With turbo boosters, Airwolf could go Mach 1+, so really nothing has progressed past the 1980's.

Source: http://en.wikipedia.org/wiki/Airwolf_(helicopter)

Except that airwolf's special capabilities are all fictional.

lol, I just popped in here to write that and saw that someone beat me to it.

As soon as I saw that title "Fastest helicopter" the only thing that popped in my head "Airwolf"

now I have the theme song in my head...

Ah yeah... "The Lady".. :D

Instant flashbacks to Jan-Michael Vincent .. Ernest Borgnine .. Alex Cord (and his cute assistants ;D) ... jeeps ... Valley of the Gods ... eagles .. a cello ... and of course that awesome and super long intro of the first episode with that lizard falling/rolling from the front wheel of the helicopter when it takes off.

As you can notice, the show did make an impression on this 5 year old in the 80's. ;D

Thank you for bringing back the memories! :)

Airwolf is the word we should use to describe things of beauty, intensity, and majesty. Shakespeare is airwolf. James Brown's music is airwolf. Sex so good it makes your spine tingle and your knees buckle -- that's airwolf! And there is nothing more airwolf... than Airwolf.

It must have a massively robust landing gear design.

Do you mean more massive than a normal helicopter? Why? The article seems to state that the newly available technologies made their new helicopter lighter than before.

"Massively robust" == "very robust"

== "robust"

Heh. I see I was down-modded, which wasn't very surprising. I was trying for exactly the kind of pun/humor that I know HN doesn't appreciate.

ObJokeExplanation: For me, the wording of the title was misleading in a funny way, since helicopters generally don't break speed records while literally on Earth.

HN does sometimes appreciate that, but you have to lead a bit. Maybe if you'd quoted the title immediately before your response, since most people will have read one or more other comments (and maybe the article itself... shocking, I know) before reading your comment. The headline has expired out of memory at this point. That's my excuse for why I didn't get it.

Why is the double rotor design not more popular than the way most helicopters are made?

My guess is complexity. The double rotors require coaxial drives and the helicopter itself ends up being taller. The top rotor maintenance is going to be more difficult.

The Kamov company's helicopters were all(?) double-rotor. http://en.wikipedia.org/wiki/Kamov

Kamen Aerospace has double rotor helicopters without the coaxial drive (interleaved rotors) http://en.wikipedia.org/wiki/Kaman_Aircraft

Complexity, yes, but for a different reason -- gyroscopic precession. Cyclic inputs for differential lift require that the actual (mechanical) blade adjustment be at an angle to the change in the lift produced. With a single rotor you can accomplish that with a simple mechanical linkage (and a bit of body english -- the angle of input precession is rarely at the "proper" 90 degrees). Counter-rotating blades mean two sets of blade pitch controls (swash plates, rods, followers and linkages, etc.) and, if you want to avoid unplanned pitch adjustments, a servo system that can moderate cyclic control input based on direction (input will be much more sensitive to fore-aft adjustment than to left-right without a compensation circuit).

> if you want to avoid unplanned pitch adjustments

I read that as 'detours to the nearest hospital'.

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