Slashdot Mirror
Buy Your Very Own Exoskeleton Flying Vehicle
dks writes "Yahoo! News is running a story about a personal flying machine originally developed for the military that straps on an individual's back and allows her to fly around for over two hours at a time. The prototype is now up for auction on eBay. The only catch--you have to agree not to operate the vehicle if you purchase it. Uh...yeah...I'm just buying it for display. Yeah, that's it."
Basically, it's a (pardon the pun) safety net for the company that made it. If you buy it (and therefore agree not to fly it), and then go ahead and fly it anyway and injure yourself, you'll have that much more of a problem successfully suing them over it.
While you cannot completely sign away your "right" to sue someone, a contract like this makes it much more difficult to collect a judgement.
Kierthos
Mr. Hu is not a ninja.
The reason they are selling the proto-type is that it got tangled up in the tether during a test hop and crashed. Its damaged and they don't have the funds to fix it. The DOD/DARPA folks that were supporting the development declined to extend the deadline(s) for demonstration of the technology after the crash.
The whole story as told from the SoloTrek perspective is on their web site. http://www.solotrek.com/
The eBay article features a link to the company designing this stuff and they have a very cool concept for a two seater: duotrek. I WANT one of these. No more fucking parking problems, that is if the roof of my appartment is strong enough...
giel.y contains 2 shift/reduce conflicts
Well, on a Russian ship it would be "Welcome to my ship. Isn't he splendid?" as the Russian navy refers to ships in the masculine, as opposed to the feminine in the US navy.
The revolution will be televised. Blackout restrictions apply.
The Auction does not say you can't fly it...
"As a condition of sale, the successful bidder will have to execute an agreement warranting that they will use the aircraft for static exhibition and educational purposes only."
There is no
As a condition of sale, the successful bidder will have to execute an agreement warranting that they will use the aircraft for static exhibition and educational purposes only.
Educational Purposes. What about LEARNING to fly it? It doesn't say you can't fly. You can exhibit it statically (i.e. not fly it), and use it for educational purposes. Just choose the latter!!
Ground effect does not apply to this type of aircraft.
For an airplane, "ground effect" is the term applied to the tendency of a wing to exhibit increased aerodynamic efficiency (basically more lift and less drag) when it's within roughly a half-wingspan of the ground. It's caused, at least in layman's terms, by a cushion of air forming beneath the wing and the ground, and by the reduction of a drag-inducing wingtip vortex.
This vehicle has no horizontal wing flying thru the air. So we can eliminate the obvious cushion of air.
Now, a helicopter demonstrates ground effect for the same basic reason as an airplane, within half a rotor-disc-diameter or so of the ground, and also because for a hovering vehicle, the downwash tends to bounce back up again to provide a additional cushion. Here's a primer on helo ground effect. As you can see, the ground effect is largely produced by the ground limiting development of a tip vortex.
Just for completeness, we can also address ground effect for a hovering jet, like the Harrier Jump Jet. In that case, the downwash bouncing up certainly provides a cushion, and the Harrier has strakes under the fuselage designed exclusively to capture that cushion of air and enhance it - kind of like a hovercraft. But for a hovering jet, you have an additional problem - the exhaust gases also tend to get reingested by the engine, lowering the engine efficiency. One of the most vexing problems for the Harrier, and also for the newer Joint Strike Fighter designs, is "hot gas reingestion". In fact, if you hover these aircraft pointing downwind, you can snuff out the engine due to lack of oxygen. (This issue is probably not a big problem for the high-bypass arrangement of the SoloTrek, where very little exhaust gas is produced.)
Now to address this vehicle. The lift is provided by ducted fans. Therefore there is no tip vortex, because the duct prevents one from forming. In fact, the duct itself provides the same effect as ground effect, by eliminating the efficiency loss due to the vortex. The only relevant part of the "ground effect" here is therefore the bouncing cushion of air. But the fans on this vehicle are mounted so high above the ground (about 7 feet), and the total thrust is so low, that a fairly minimal ground effect cushion can be developed. In fact, in the pictures on Ebay, at least one of the photos shows the thing high enough up (the fans are at least 12 feet off the ground) that any ground effect that might exist would be almost totally eliminated.
So it's extremely unlikely that this vehicle's performance would change significantly with climbing away from the ground.
--Brandon / Split Infinity Music
This is the 29th year of Moller vaporware. I have a 1974 brochure for Moller's "Discojet", which was supposed to be for sale Real Soon Now. This was a saucer-shaped flyer with eight Wankel engines. The brochure mentions prototypes going back to 1967. So he's been at this for 36 years now. Unsuccessfully.
Not for lack of money, either; substantial funds have gone into this project.
Small thrust-only flyers have been built. Several from the 1950s are at the Hiller Museum in Redwood City, CA, and they actually flew. They have the famous Hiller Flying Platform. Such vehicles are inherently unstable and hard to fly, but not impossible to build. The stability problem ought to be solveable today - many modern military aircraft are stable only because a control system is constantly struggling to keep them stable. But an unstable VTOL is the worst case - aerodynamic control surfaces are ineffective at low speeds, adjusting engine thrust has too much lag, engine gimbals add weight, and thrust deflector plates waste power. The Harrier fighter, after 30 years, remains the only succesful pure-thrust VTOL.
You obviously never read the site.
1.) Notice there is only ONE Solotrek for sale, and there were two orginal Solotrek XFV prototypes, one that crashed, causing them to miss the fatal milestone, and another unscathed on.
2.) As said by Goldenhawk, the ground effect does not apply. Though you are right, it's never flown untethered.
3.) Originally, Trek Aerospace planned on just closing its doors, but since the last article has updated their status and website greatly. The eBay auction states that the proceeds of the auction will go towards funding for the NEXT generation Solotrek vehicle, which has a much more conservative timeline.
4.) According to Trek Aerospace's original statement about closing their doors, they were quick to mention that the first prototype only crashed because of a change in the management at DARPA, who would not allow them to extend the deadline of the milestone they would eventually miss. As such, they were forced to fly in inclement conditions, which were blamed for the crash.
5.) The eBay auction, also states "As a condition of sale, the successful bidder will have to execute an agreement warranting that they will use the aircraft for static exhibition and educational purposes only."
As a personal note, after not metioning that the vehicle was not in one piece, and showing pictures of a fully functional Solotrek, I'm sure it would have to be some form of misrepresentation to just hand the winner a broken Solotrek in a box of parts.
--- What
A much cheaper ($30,000) personal flying machine that you can buy right now in kit form can be found here and here. These things do actually fly.