Optimizing Air Pressure for Hovering: Calculating the PSI Needed for Static Lift

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Discussion Overview

The discussion revolves around calculating the air pressure (PSI) needed for a hovercraft-like object to achieve static lift. Participants explore the relationship between the object's dimensions, mass, and the necessary air pressure to maintain hover, considering factors such as the skirt design and potential air leaks.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant seeks to determine the PSI required for a 250 lb mass using compressed air, questioning the role of buoyancy when air pressure equals the object's mass.
  • Another participant provides a link to a hovercraft design calculator, suggesting it may assist in the calculations.
  • Concerns are raised about the tone of the discussion, with one participant expressing frustration over perceived demands for assistance and the implications of sharing ideas for profit.
  • A later reply questions the skirt's design, asking whether it forms a perfect seal with the ground or has a gap, noting that this affects the pressure calculation.
  • One participant calculates that if there is a perfect seal, the required pressure would be approximately 0.87 PSI above atmospheric pressure, based on the object's dimensions and mass.
  • Another participant mentions that if the hovercraft operates on water, it would displace water equal to its mass, similar to a boat.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the skirt's seal and its impact on pressure calculations. There is no consensus on the exact PSI needed, and the discussion remains unresolved regarding the implications of air leaks and skirt design.

Contextual Notes

Participants have not fully clarified assumptions regarding the skirt's design and its interaction with the ground, which may affect the calculations. The discussion also reflects varying levels of familiarity with the technical aspects of hovercraft design.

c2it4u532
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I want to create lift of an object about the size of 36 in by 8 in. the lift would be provided by
compressed air and the object would have an air dam and skirt (like hovercraft) and lift approx
250 lb mass on it to floatation level of .05 in (where skirt would not reach above lift surface.
What type of psi would it take to constant hover. Assume Skirted area is approx. the area of
the underside of the object. If air pressure underneath equals mass of object doesn't buoyancy
occur?
 
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Its not a tennis court and its not a game. I need some assist in calculating some issues.
Itought I had the numbers to start and and wondering if these values are right. IF you have heard of Kickstarter.com , then you or a few of your associates might understand. I am not going back to school to learn values and then make other people very prosperous for sharing ideas. To your benefit and mine. Thanks for the input. your reply appreciated.
 
c2it4u532 said:
Its not a tennis court and its not a game. I need some assist in calculating some issues.
Itought I had the numbers to start and and wondering if these values are right. IF you have heard of Kickstarter.com , then you or a few of your associates might understand. I am not going back to school to learn values and then make other people very prosperous for sharing ideas. To your benefit and mine. Thanks for the input. your reply appreciated.
If that's your attitude, you're in the wrong place. Most of the teachers here are world-class experts in their fields. (I'm not one of those, but anyone that I cite is.) One of my loves is hovercraft, and Russ was kind enough to find that calculator site. If you don't appreciate that, then I don't want to have any further contact with you. And the quote about the tennis court is my signature that is included automatically in everything that I post. It has nothing to do with you.

edit: By the bye, you don't demand things here; you request them or hit the road.
Also, why should we help you to make money that you have specifically stated we will have no share of?

2nd edit: Even if we help you, Greg will own the patent since it will be designed on his site and he owns all rights to it.
 
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I apologize if I offended you and my intentions were not in that direction. I am not demanding anything.
 
Accepted on my behalf. Perhaps it was a communications misunderstanding, and I over-responded.
 
I don't understand what you mean by "the skirt would not reach above lift surface"? Is there a gap at the bottom of the skirt or does the skirt form an air tight seal with the "ground"?

If there is a perfect seal the required pressure is easy to calculate..

It's just 250/(36x8)= 0.87psi above atmospheric.

If there is gap/air leak the required pressure is the same but you need to calculate the flow rate required which is beyond my experience.
 
If it's on water the same rules on displacement occur. eg a hovercraft displaces water equal to it's mass just like a boat.
 

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