Mach 8.9 - on land

[docm]

http://www.popularmechanics.com/science/extreme_machines/4246209.html<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Next week, engineers at Holloman Air Force Base in New Mexico will try to break a land speed record, blasting a rail-mounted rocket sled at Mach 8.9 during a test of a classified Navy system. The test is scheduled to occur Jan. 30, officials there tell PM.<br /><br />The test is part of a secret project for the Navy, which is asking Holloman’s test team to propel a secret payload, designed at Sandia National Laboratories, at 1.88 miles per second.<br /><br />In 2003, the same sled track (pictured above) was used to bust the standing land speed world record for a vehicle on rails. During that test, which sent payloads at Mach 8.47 (6453 mph), 13 rocket motors drove the sled in stages. As the first stage burned out, its sled detached and slowed while the next ignited. The test was performed to validate upgrades to the track, the world’s longest, fastest test facility.<br /><br />The 10-mile Holloman High Speed Test Track is seen as a bridge between laboratory experiments and expensive, possibly dangerous test flights. It’s used to test ejection seats, missile defense components, the impact strength of bunker-busting bombs and the release of sub-munitions at high speeds. Operated primarily for Air Force Materiel Command, the facility is also available to other government agencies and defense contractors. The Navy is one of the first agencies to bring its hardware out for testing on the upgraded track, Holloman officials say.<br /><br />So what could they be testing? Not many things go faster than Mach 8—munitions from electromagnetic rail guns go that fast. Hypersonic missiles with scramjets can also reach those speeds—the airflow in a scramjet engine remains supersonic throughout the combustion process and does not require choking mech</p></blockquote> <div class="Discussion_UserSignature"> </div>

 

[j05h]

Real Men Ride Rocket Sleds:<br />http://www.ejectionsite.com/stapp.htm<br /><br />Doc- great article about the Holloman track. When we all talk about space development this and testing that, these facilities are the sorts of ground-level things that can really make the difference. Mach 8.9 is nothing to sneeze at, too. Gotta wish those guys luck on that run.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[richalex]

When I first read about these large Mach numbers on a ground-based sled, I could not believe it. I think it is fantastic that we can propel a large object at that speed at ground level and still have it intact. Of course, we have to do some funny tricks to make it work. I saw pictures on a website showing a long, plastic-sheet tunnel around the track, which was used to create a helium atmosphere for the rocket. If it were regular air, the sled would disappear in a puff of smoke!

 

[exoscientist]

While doing a web search I found a report on creating inflatable vacuum chambers, where the walls are filled with pressurized gas for strength. Such chambers could even be buoyant if the walls were filled with a lighter than air gas such as helium.<br />This then could be used to extend a vacuum travel path from the ground all the way to high altitude for orbital rocket launch.<br /><br />Stability Analysis of an Inflatable Vacuum Chamber.<br />http://arxiv.org/abs/physics/0610222v4 <br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[publiusr]

The so called "vacuum filled" balloons. Interesting.

 

[nec208]

<p>I don't really see the point ? Like why are they&nbsp;doing it and how will it help the navy?&nbsp;</p><p>They should be learning how to shoot nukes down.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[Cygnus_X_1]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I don't really see the point ? Like why are they&nbsp;doing it and how will it help the navy?&nbsp;They should be learning how to shoot nukes down.&nbsp; <br /> Posted by nec208</DIV></p><p>&nbsp;</p><p>It is easier to test different systems on a captive vehicle.</p><p>" learning how to shoot nukes down. " is not the Navy's primary task </p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[KosmicHero]

<p>&nbsp;</p><p>ummm.... Yes they should be learning how to shoot nukes down.&nbsp; That sounds like an excellent technology to test using a Mach 8.9 rocket sled. Don't you think?</p><p>&nbsp;What I'd like to know is when are they going to test something that isn't classified so I can go watch? </p> <div class="Discussion_UserSignature"> kosmichero.wordpress.com </div>