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#1
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jet pack
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#3
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jet pack
I totally agree with Tony...even in the company's demonstration video 2
people are always there "walking" the flyer....sort-of reminds me just abit of the Mollier Flying Car or whatever it's called. It DOES look like a lot of FUN, though!!! I also hope the thing succeeds....30 minutes running on this as they say is so much better than the 43 seconds that the "Go Fast Sports" JetPack can fly. Ted "Anthony W" wrote in message news19kk.556$JH5.435@trnddc06... wrote: Sounds like it's actually motor driven. http://www.cnn.com/2008/TECH/ptech/0....ap/index.html Karl It's nothing new, this has been around for a while but I don't see much hope for it working as claimed. Tony |
#4
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jet pack
Ted wrote:
I totally agree with Tony...even in the company's demonstration video 2 people are always there "walking" the flyer....sort-of reminds me just abit of the Mollier Flying Car or whatever it's called. It DOES look like a lot of FUN, though!!! I also hope the thing succeeds....30 minutes running on this as they say is so much better than the 43 seconds that the "Go Fast Sports" JetPack can fly. Ted I think this think is pretty much a Moller for one. If it ever gets more than 5' off the ground it will be very unstable. Tony |
#5
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jet pack
I was listening to the EAA webcast, and they said that the FAA required
them to hang on the the thing during that demo because of all the people standing in the area. There's supposed to be a better demo during today or tomorrow's airshow where it will lift off away from everyone. In any case, it isn't a "Jet", but a ducted fan. Sounds like a big leaf blower. Anthony W wrote: Ted wrote: I totally agree with Tony...even in the company's demonstration video 2 people are always there "walking" the flyer....sort-of reminds me just abit of the Mollier Flying Car or whatever it's called. It DOES look like a lot of FUN, though!!! I also hope the thing succeeds....30 minutes running on this as they say is so much better than the 43 seconds that the "Go Fast Sports" JetPack can fly. Ted I think this think is pretty much a Moller for one. If it ever gets more than 5' off the ground it will be very unstable. Tony |
#6
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jet pack
I just heard from Martin (through EAA Radio) that they won't be flying
again this week. They say they've been overworked and tired, so they don't want fatigue causing an accident. There was also talk about insurance issues, but it seems like the pilot capability issue trumped that. Paul Dow (Remove CAPS in address) wrote: I was listening to the EAA webcast, and they said that the FAA required them to hang on the the thing during that demo because of all the people standing in the area. There's supposed to be a better demo during today or tomorrow's airshow where it will lift off away from everyone. In any case, it isn't a "Jet", but a ducted fan. Sounds like a big leaf blower. Anthony W wrote: Ted wrote: I totally agree with Tony...even in the company's demonstration video 2 people are always there "walking" the flyer....sort-of reminds me just abit of the Mollier Flying Car or whatever it's called. It DOES look like a lot of FUN, though!!! I also hope the thing succeeds....30 minutes running on this as they say is so much better than the 43 seconds that the "Go Fast Sports" JetPack can fly. Ted I think this think is pretty much a Moller for one. If it ever gets more than 5' off the ground it will be very unstable. Tony |
#7
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jet pack
Paul Dow (Remove CAPS in address) wrote:
I just heard from Martin (through EAA Radio) that they won't be flying again this week. They say they've been overworked and tired, so they don't want fatigue causing an accident. There was also talk about insurance issues, but it seems like the pilot capability issue trumped that. Paul Dow (Remove CAPS in address) wrote: I was listening to the EAA webcast, and they said that the FAA required them to hang on the the thing during that demo because of all the people standing in the area. There's supposed to be a better demo during today or tomorrow's airshow where it will lift off away from everyone. In any case, it isn't a "Jet", but a ducted fan. Sounds like a big leaf blower. Anthony W wrote: Ted wrote: I totally agree with Tony...even in the company's demonstration video 2 people are always there "walking" the flyer....sort-of reminds me just abit of the Mollier Flying Car or whatever it's called. It DOES look like a lot of FUN, though!!! I also hope the thing succeeds....30 minutes running on this as they say is so much better than the 43 seconds that the "Go Fast Sports" JetPack can fly. Ted I think this think is pretty much a Moller for one. If it ever gets more than 5' off the ground it will be very unstable. Tony It's supposed to be fairly stable because the thrust reaction point is well above the CG, so there is a strong pendulum effect. They claim it's better than a helicopter. I spoke with one of the promoters at the convention and asked about the engine failure issue. The engine is a liquid cooled V4 which I assumed was a marine engine. Like Moller they will be relying on one of those "zero-zero" (almost) ballistic parachutes that use an explosive device to spread the canopy when there is line stretch so that in theory it is already inflated before you've moved down more than 10 or 20 feet or something like that. Below the parachute safety altitude, they are relying on a kind of shock strut that sticks down between your legs to absorb the fall and save your back, which is supposed to be effective to about 10 feet. It's the middle zone between the parachute minimum altitude and the shock strut that they don't account for, and they haven't tested a parachute yet to see just what the "dead man's" altitude range is. In any event, anybody flying the thing will be working to spend as little time as possible between 5-10 feet and the altitude that the parachute is effective. You sure wouldn't get me in the damn thing. They sold one of them by Thursday. 100 grand. Crazy. John |
#8
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jet pack
"John" wrote in message
... ... It's supposed to be fairly stable because the thrust reaction point is well above the CG, so there is a strong pendulum effect. They claim it's better than a helicopter. An often made, completely wrong assumption - "pendulm effect" - ain't no such thing for an object in free flight. Early rocket experimenters often attempted use "tractor" engines assuming that it would provide stability - Dr. Robert Goddard's first liquid rocket is an example. It didn't take them long to figure out that they were wrong. -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#9
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jet pack
Capt. Geoffrey Thorpe wrote:
"John" wrote in message ... ... It's supposed to be fairly stable because the thrust reaction point is well above the CG, so there is a strong pendulum effect. They claim it's better than a helicopter. An often made, completely wrong assumption - "pendulm effect" - ain't no such thing for an object in free flight. Early rocket experimenters often attempted use "tractor" engines assuming that it would provide stability - Dr. Robert Goddard's first liquid rocket is an example. It didn't take them long to figure out that they were wrong. So much for the roll stability advantage of high wing aircraft... Perhaps the word should be controllability, not stability. Are you saying the thing would have the same controllability with the thrust at the top or bottom? |
#10
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jet pack
"John" wrote in message
... Capt. Geoffrey Thorpe wrote: "John" wrote in message ... ... It's supposed to be fairly stable because the thrust reaction point is well above the CG, so there is a strong pendulum effect. They claim it's better than a helicopter. An often made, completely wrong assumption - "pendulm effect" - ain't no such thing for an object in free flight. Early rocket experimenters often attempted use "tractor" engines assuming that it would provide stability - Dr. Robert Goddard's first liquid rocket is an example. It didn't take them long to figure out that they were wrong. So much for the roll stability advantage of high wing aircraft... Perhaps the word should be controllability, not stability. Are you saying the thing would have the same controllability with the thrust at the top or bottom? You betcha. Ain't no difference at all. Well, not exactly, there can be differences due to the abilitly to align the thrust axis with the CG, or the location of any control surfaces and their relation to the CG, or the location of the CG... But pendulum's have nothing to do with it. Take the wife's heirloom grandfather clock and throw it off the roof - you will observe that the "heavy end" of the pendulm doesn't "hang down" or fall any faster than the rest of the clock once you have let go of it. Any difference between tractor and pusher aircraft controllability that can't be explained by the change in airflow over the control surfaces? -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
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