Why did the half-plane, half-helicopter not work? | Hacker News Reader

Why did the half-plane, half-helicopter not work?

bbc.co.uk

41 pointsjayflux15 comments

Hmm, I'd say that V22 Osprey does work. It's still a compromise and a full heli or full plane is better suited for most tasks but a hybrid does have its use.

This graph shows how much better the Osprey's tiltrotor design is compared to the Fairey Rotodyne's compound design:

http://www.defense-aerospace.com/dae/articles/communiques/AW...

there are times where the V22 looks straight out of a science fiction movie. https://upload.wikimedia.org/wikipedia/commons/1/15/3rd_Batt...

Eh. The total cost of its program ($35.6 billion) almost came to exactly $1 billion per death incurred by accidents during its testing from 1991-2000(36 fatalities). All that money and life spent on a somewhat functional newly minted freedom boner.

I don't think "death per budget" is a meaningful metric, unless talking about weapons or serial killers. You can't just take two numbers we want to minimize, divide one by another, and claim significance.

Multiplying them would be more meaningful.

Is $35 billion a lot of money? We did get a step forward in engineering. The lessons learned advanced our knowledge forever. The money spent in actual wars for little things like air conditioning, for example, cost more:

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-w...

That was my first thought as well (off the title alone), and I'm somewhat surprised the article didn't mention the Osprey at least in passing.

I mean, you can certainly argue that the program was not worth the cost in money or lives lost (as is already being done in this subthread), but ultimately the thing works -- as someone who lives in San Diego, I see them flying overhead multiple times per week.

I was watching a documentary years ago (vhs tape) that talked about how there were problems with the Osprey. The lingering question I had was whether it was a problem of that design or the concept. https://en.wikipedia.org/wiki/Accidents_and_incidents_involv...

Although not meant for passenger service, the AH-65 [1] would likely have been a successful hybrid had the stopgap Cobra not been such a resounding success.

[1] https://en.wikipedia.org/wiki/Lockheed_AH-56_Cheyenne

Another tip jet helicopter was the Sud-Ouest Djinn [1] from the 1950s. This design was somewhat successful, with 178 units being built. Unlike other tip jet designs, the Djinn used a fixed gas turbine to drive an air-compressor, and the blades were simply powered by compressed-air tip jets. Since tip jet driven rotors don't generate a lot of torque, the Djinn didn't have a tail rotor.

[1] https://en.wikipedia.org/wiki/Sud-Ouest_Djinn

Too big and too complex. Just like the Osprey.

But Canadair has it all figured out. The CL-84 was a tilt-rotor, tilt-wing aircraft that was landing troops on US carriers 40 years ahead of the Osprey. It probably had 1/100th the part count.

https://en.wikipedia.org/wiki/Canadair_CL-84

Helicopters are expensive - high fuel consumption, high maintenance. They're also inherently much less safe than an airplane. A helicopter is inherently unstable (it wants to crash, whereas an airplane wants to fly), and losing a rotor blade means everyone dies (hence the high maintenance costs).

What's the state of the art in active anti-noise technology for helicopters? I've read about that kind of thing a few times, but don't know what actual numbers are.

It would be hard to anti-noise the Rotodyne because it literally had small jet engines on the end of each rotor - which was why it so incredibly loud in VTOL.

I can't find actual noise figures for it, but I suspect it wasn't all the much louder than some modern jet liners. But jet liners land at out-of-city airports, and the whole point of the Rotodyne was that it could land in the middle of a city - and you're not going to get certification for that for a plane that can be heard miles away.

I'd guess it was unbearably noisy inside the cabin too.

Here's a sales video, with vintage cheesy music and equally vintage British accents:

https://www.youtube.com/watch?v=u4Z1UnRZDyo

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