In message <4965E869.4090205@rubidium.dyndns.org>, Magnus Danielson writes: >Ericsson created a rack system in which the bottom of the rack >was actually forming a closed container with the floor. We had that at one place I worked, except it was two small "dogs" you attached front and back a standard 19" rack. Trouble was that you had to wash the floor first, or the dust would blow all over the place. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

Poul-Henning Kamp skrev: > In message <4965E869.4090205@rubidium.dyndns.org>, Magnus Danielson writes: > >> Ericsson created a rack system in which the bottom of the rack >> was actually forming a closed container with the floor. > > We had that at one place I worked, except it was two small "dogs" you > attached front and back a standard 19" rack. I never seen it myself, so you have more correct info. I go back from something told to me way back in time, so details got a bit fuzzy. > Trouble was that you had to wash the floor first, or the dust would > blow all over the place. You also have some rather high requirements on the floor quality, it needs to be fairly flat as well. Cheers, Magnus

> -----Original Message----- > From: time-nuts-bounces@febo.com > [mailto:time-nuts-bounces@febo.com] On Behalf Of Magnus Danielson > Sent: Thursday, January 08, 2009 11:19 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPSDO time constant > > Poul-Henning Kamp skrev: > > In message <4965E869.4090205@rubidium.dyndns.org>, Magnus > Danielson writes: > > > >> Ericsson created a rack system in which the bottom of the rack was > >> actually forming a closed container with the floor. > > > > We had that at one place I worked, except it was two small > "dogs" you > > attached front and back a standard 19" rack. > > I never seen it myself, so you have more correct info. I go > back from something told to me way back in time, so details > got a bit fuzzy. > > > Trouble was that you had to wash the floor first, or the dust would > > blow all over the place. > > You also have some rather high requirements on the floor > quality, it needs to be fairly flat as well. > When I worked in the special effects business, we used to use these all the time to move heavy stuff around. It actually doesn't require a "real flat" floor (1 cm grooves aren't a big issue). Think about them as small hovercraft. It also doesn't take much air pressure to lift things (large area * small pressure). For instance, folks build small hovercraft using electric leaf blowers as the pressurization fan to support a disk some 1.2m in diameter which will easily support a couple people. The lift pads we used were about 30cm in diameter. 1 psi (7kPa) lifts about 50kg. Moving around 1 ton things with 4 pads wasn't unusual. The rougher the floor, the more airflow you need.

 When I worked in the special effects business, we used to use these
 all the time to move heavy stuff around. It actually doesn't
 require a "real flat" floor (1 cm grooves aren't a big issue).
 Think about them as small hovercraft. It also doesn't take much air
 pressure to lift things (large area * small pressure).  For
 instance, folks build small hovercraft using electric leaf blowers
 as the pressurization fan to support a disk some 1.2m in diameter
 which will easily support a couple people.

 The lift pads we used were about 30cm in diameter. 1 psi (7kPa)
 lifts about 50kg. Moving around 1 ton things with 4 pads wasn't
 unusual.

 The rougher the floor, the more airflow you need.

"Lux, James P" wrote: When I worked in the special effects business, we used to use these all the time to move heavy stuff around. It actually doesn't require a "real flat" floor (1 cm grooves aren't a big issue). Think about them as small hovercraft. It also doesn't take much air pressure to lift things (large area * small pressure). For instance, folks build small hovercraft using electric leaf blowers as the pressurization fan to support a disk some 1.2m in diameter which will easily support a couple people. The lift pads we used were about 30cm in diameter. 1 psi (7kPa) lifts about 50kg. Moving around 1 ton things with 4 pads wasn't unusual. The rougher the floor, the more airflow you need. James, Do you have any web sites that show such a contration using leaf blowers ? thanks, Bill....WB6BNQ

On Thu, Jan 8, 2009 at 11:36 AM, WB6BNQ <wb6bnq@cox.net> wrote: > Do you have any web sites that show such a contration using leaf > blowers ? mythbusters -- GDB has a 'break' feature; why doesn't it have 'fix' too?

Do you have any web sites that show such a contration using leaf
blowers ?

thanks,

Bill....WB6BNQ

Google "Leaf blower hovercraft" and you'll get dozens of useful hits. Here's a real old link: http://amasci.com/amateur/hovercft.html > -----Original Message----- > James, > > Do you have any web sites that show such a contration using leaf > blowers ? > > thanks, > > Bill....WB6BNQ