Aces High Bulletin Board

General Forums => The O' Club => Topic started by: Saintaw on June 14, 2006, 04:35:29 AM

Title: Using gravity to get off the ground
Post by: Saintaw on June 14, 2006, 04:35:29 AM: http://www.shoutwire.com/viewstory/15905/Using_Gravity_To_Get_Off_The_Ground
(http://www.machinedesign.com/Content/Issue/10637/aerospace1.jpg)
Title: Using gravity to get off the ground
Post by: deSelys on June 14, 2006, 05:15:16 AM: Cool idea, but if I may nitpick the article, I wonder how do you 'release vacuum'....?
Title: Using gravity to get off the ground
Post by: Saintaw on June 14, 2006, 05:16:11 AM: Like I care!!! (You think that's high enough for a propper jump?) :D
Title: Using gravity to get off the ground
Post by: storch on June 14, 2006, 06:05:01 AM: no more jump references from you.
Title: Using gravity to get off the ground
Post by: deSelys on June 14, 2006, 07:11:34 AM: LOL Storch, you'd better get used to it. It looks like Saw has contracted the nastiest form of the virus.

To answer your question Saw, everything that can reach 3,500 ft without flying faster than 400 kph is jumpable to my eyes....

If I was rich, I would rent THIS:

(http://www.zeppelin-nt.de/images/gallerie/fertig/sn202.jpg)
Title: Using gravity to get off the ground
Post by: Saintaw on June 14, 2006, 07:21:54 AM: I have images of burning Zeps somewhere in my mind... something famous, I'm sure it'll come back.

storch, will do if you stop making references to your jebus and your superior morals... deal? :p
Title: Using gravity to get off the ground
Post by: bozon on June 14, 2006, 09:48:54 AM: Quote
Originally posted by deSelys
Cool idea, but if I may nitpick the article, I wonder how do you 'release vacuum'....?

suck air in.

what I find wrong is:
Quote
If the design pans out, the plane won't need any fossil fuel and will have a virtually unlimited range.

Thermodynamics will have to disagree. You'll need to invest energy in creating vacuum again if you want to climb after you stoped, or compress the Helium like they suggested.
Unless you just get carried by the winds, you have to invest energy to sustain movement.

Also, supporting vacuum in a large surface area structure requires a very strong construction. That usually results in increased weight and an even larger structure volume for it to float. Unless you can use very advance (and expensive) materials, it is much easier to handle internal over pressure or heat then vacuum.

Bozon
Title: Using gravity to get off the ground
Post by: deSelys on June 14, 2006, 10:11:39 AM: I know Bozon, I was just making fun of the phrasing: you just can't 'release' void.

I also think that the inventor is a bit optimistic about the energy balance. However, this design could very well work with very little external energy needed. Solar panels could be enough to fill the gap.

When I was a teen, I imagined for a sci-fi RPG adventure a vehicle based upon a shaped force-field: with air sucked out of the field it would rise, then the force-field would take the form of a wing and it would glide.
Title: Using gravity to get off the ground
Post by: Nilsen on June 14, 2006, 10:26:25 AM: Quote
Originally posted by deSelys
you just can't 'release' void.

your mom did once :p
Title: Using gravity to get off the ground
Post by: lukster on June 14, 2006, 10:31:28 AM: How long would it take to "float" high enough for these "dives". This sounds interesting but travel by sail or covered wagon might be faster.
Title: Using gravity to get off the ground
Post by: deSelys on June 14, 2006, 10:35:41 AM: Quote
Originally posted by Nilsen
your mom did once :p