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Comment: Re:Blastoff From the Past (Score 2) 19

by N22YF (#47934755) Attached to: ULA and Jeff Bezos' Blue Origin Announce Rocket Engine Partnership

Looking at Bezos's New Shepherd Vertical Takeoff Vertical Landing vehicle you might think that somewhere along the line Jeff caught a glimpse of Boeing's old design.

I assume you're talking about the right image in the Encyclopedia Astronautica link - that is an educated (and ultimately incorrect) guess by Encyclopedia Astronautica of what the vehicle would look like, from years before actual images were released (see http://www.blueorigin.com/upda...).

Comment: Re:I don't think the cypher is the problem. (Score 1) 270

by N22YF (#42971209) Attached to: US Stealth Jet Has To Talk To Allied Planes Over Unsecured Radio

Incorrect. The F-22 and F-35 have both active and passive seekers, and they're able to determine range, altitude, and bearing with just their passive seeker.

What passive seeker are you referring to on the F-22? It doesn't have much, relatively, and certainly nothing like the F-35's infrared search and track/electro-optical targeting system. The F-22 normally relies on either datalinked targeting information from another aircraft or its own LPI (low-probability-of-intercept) radar.

Comment: Re:I don't think the cypher is the problem. (Score 1) 270

by N22YF (#42971127) Attached to: US Stealth Jet Has To Talk To Allied Planes Over Unsecured Radio

the only passive seeker that will always remain effective is IR band, because they kinda need the engines to fly. but its also rather short range, wont give real accurate RAB (RAB being only really relevent for BVR) and if you're that close and can pickup his tailpipes, you already know where he's at, and which way hes going.

Actually, modern infrared search and track systems (http://en.wikipedia.org/wiki/IRST) are quite capable - the range is less than radar, but can be dozens of miles, which is plenty of distance to acquire and track a target and launch a missile, which could also employ a passive seeker.

Comment: Re:Occam's Razor (Score 1) 339

by N22YF (#34993970) Attached to: Chinese Stealth Fighter Jet May Use US Technology

The fact that they don't even produce a 4th generation fighter of their own design (most of their fighters are copied/adapted from Russian designs) and suddenly they unveil this supposed 5th generation fighter supposedly without any foreign technology.

This statement would have held weight 15 years ago, but China's been modernizing their military quickly. They have recently designed (and put into service) the capable J-10 themselves, including a modern updated version (J-10B), as well as the JF-17 with Pakistan.

Comment: Re:No surprise (Score 2) 339

by N22YF (#34993880) Attached to: Chinese Stealth Fighter Jet May Use US Technology

Technology stolen would probably include anti-radar coatings and perhaps engine and avionics.

The J20 is simply too big to be very stealthy.

Size has little to do with stealth. The B-2 is about seven times as big as the F-117, but still manages a radar cross-section of 0.1 square meters.
Not to mention that we don't actually know the J-20's dimensions or weight. It may not be any bigger than an F-22.

Anti-radar coatings is a reasonable guess, but China has access to much more modern engine and avionics technology via Russian fighter jets.

Comment: Re:Since when... (Score 1) 371

by N22YF (#33126692) Attached to: The Bus That Rides Above Traffic

You mean like ... china, paper, woodblock printing, gunpowder, compass, the fork, fireworks, go, maglev wind power generators, negative numbers, menus, tea, toilet paper or the toothbrush?

I mean, granted, not all of these are new things - in fact most of them are all fairly old (the maglev being the exception), but I really doubt any of us would want to go without them.

You mean the maglev that was designed and built by Germans?

Comment: Re:Key Points (Score 1) 215

by N22YF (#32516816) Attached to: FAA Adds a Study On Adding Drones To Commercial Aviation

1. They are not talking about autonomous UAVs. These UAVs are essentially remote-controlled aircraft piloted by real pilots. I think some people assume these things think for themselves but that's not the case. Now that doesn't automatically discount concerns of safety, but "skynet" is not the case here.

Well they're not really remote-controlled aircraft; instead of responding to, say, pitch, roll, and throttle commands, you tell them where to go and what to do and they figure out how to get there themselves. This has worked out very well for the military, but the FAA hasn't trusted UAVs enough to allow them to prove themselves in large-scale civil usage. For example, the military wanted to use their UAVs to help out with Katrina efforts, but since it was in civil airspace, they weren't allowed to.

2. This is not specifically for military only. Many uses for UAVs exist outside of military applications such as basic transport. Of course they'll use them for surveillance, but they already do that with aircraft. UAVs can simply linger longer because one pilot can take over during flight. Similar to how large aircraft do it now with redundant crew members.

I think initially these are going to be used to supplement/replace things like news, traffic and police aircraft/helicopters. NASA's already been using some for years to help with monitoring California wildfires.

Comment: Re:777 slimmer and faster than 747 (Score 1) 366

by N22YF (#26803013) Attached to: The Flying Giant Is 40 Years Old

747-400 still has slightly longer range than 777. The longest flights are still on 747s - Newark NJ -> Singapore (nonstop).

Actually I believe all the 777 models currently in production (777-200ER, 777-200LR, 777-300ER) have longer range than the 747-400 (although the older models, the 777-200 and the 777-300, did not). Also, the last passenger 747-400s produced have a similar interior to the 777.

I believe Newark-Singapore nonstop is only flown by the A340-500.

777-200: 5235 nm
777-300: 6015 nm
747-400: 7259 nm
747-400ER: 7670 nm
777-200ER: 7700 nm
777-300ER: 7930 nm
777-200LR: 9450 nm (!!)

Comment: Re:So... I've been living on Mars? (Score 1) 139

by N22YF (#26247509) Attached to: Managing Last.FM's "Mountain of Data"

Now I'm completely lost. How would YOU not know what song YOU are playing? If there is song tag info, wouldn't your player display that for you? Why on Earth would anyone need to connect to some service for this info?

Well, Last.fm has to know the correct artist and song name for their algorithms to work best (so they can group all songs played by that artist together, for example). Sometimes people misspell a name ("Stained" instead of "Staind", or something), and it would be detrimental to Last.fm's data mining if it treated some Staind songs as being by "Stained" instead.

That being said, the prime function of Last.fm is not to correct mistagged songs, but doing so aids its algorithms and makes the website more useful, since it more accurately reflects its users' listening habits.

Comment: Re:Kuiper Airborne Observatory (Score 1) 85

by N22YF (#25588787) Attached to: Boeing 747 Modified To Act As Infrared Telescope
True, the Kuiper Airborne Observatory (KAO) was retired in 1995 to free up funding for SOFIA. Work on SOFIA started in the 90s and it made its first flight with the telescope installed last year. SOFIA is a similar idea to KAO, but on a much larger scale (the telescope is 2.5 m in diameter, compared to 91.5 cm for the KAO) and representing a significantly larger engineering challenge.

But yeah, I don't know why this is news now. Science flights aren't supposed to start taking place until next year.

Interestingly, it won't really be ready for science flights next year, but every ten years the US National Research Council does its decadal surveys of all the science programs it's supporting and decides which ones to continue funding on. SOFIA's been so delayed that if it doesn't have any science results by mid-2009 (when the 2010 decadal survey will be taking its data), it runs a real risk of having its US government funding cut. If this happens, DLR (German Aerospace Center), another one of the big funders, will be likely to cut funding as well, resulting in a bleak future for the SOFIA program.

(I worked on SOFIA as an intern at NASA last year.)

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