Truax Engineering

[tap_sa]

Just found this nice collection of articles and videos about the Grand Old Man of BDBs, Robert C. Truax and his designs. Check out the end of first pdf, STS stack would have fitted into SeaDragon's first stage!

 

[publiusr]

I hear he is in bad health.

 

[rocketman5000]

Did you pick up on this after reading about the Sea Dragon in M&L? There was a rather good discussion going on on what was needed to further Private Aerospace<br />

 

[spacester]

Nah, I can pretty much guarantee that Tap_Sa has been all over Sea Dragon for years.<br /><br />That archive is new to me, thanks! <div class="Discussion_UserSignature"> </div>

 

[j05h]

>I hear he is in bad health.<br /><br />That's a bummer. He has been a working engineer since at least the mid-1950s, so he must be quite old at this point. His contributions will long outlive him. In many ways his design concepts are going to, IMHO of course, be roughly the course to industrial space-launch. It hasn't happened yet, but his various sea-launched concepts and low-cost engines could very easily be the CATS revolution. <br /><br />I wish him the best for his remaining times.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[pmn1]

The LEO on the Cheap link is interesting. <div class="Discussion_UserSignature"> </div>

 

[publiusr]

John London is at Marshall these days. I speak to him every so often. I got him in touch with Todd Sedler at the Northrup Grumman Newport News shipyard--where they build subs--perfect for Sea Dragon. Northrup bought TRW which said a lot of good things about Sea Dragon.<br /><br />The folks running things today have water on the brain though.

 

[publiusr]

Bump

 

[publiusr]

Neptune Spar as Sea Droagon?<br />http://uplink.space.com/showflat.php?Cat=&Board=businesstech&Number=517773&page=0&view=collapsed&sb=5&o=0&fpart=2&vc=1#Post517773

 

[pmn1]

Did anyone look at Truax type designs for the X prize? <div class="Discussion_UserSignature"> </div>

 

[j05h]

Neptune Spar shipyard would definitely be a candidate for building Sea Dragon. <br /><br />I just had a thought: what would Sea Dragon be like with a cluster of RS-68s? Boeing did drop tests with an inflatable boattail years ago, so there is some precedent. It would make a slightly different vehicle, but eliminates developing the new enormous engine. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[barrykirk]

RS-68's would be totally inappropriate for a sea-dragon<br />style rocket. The RS-68 is a low thrust to weight ratio<br />hydrogen engine.<br /><br />One of the advantages of Sea Dragon is the cheap <br />construction cost using thick steel for the tank.<br /><br />Hydrogen is much lower density than Kerosene so the<br />tank would be much larger. A larger thick wall tank is going to be much heavier. Also, insulating that tank is <br />going to be interesting at best.<br /><br />With the low thrust to weight ratio of the RS-68 engine,<br />your going to need a lot of them to lift a Sea Dragon <br />out of the drink.<br /><br />Also, the engines on a sea dragon need to start and <br />deliver thrust from underwater. I have no idea how a<br />hydrogen engine would perform under those conditions.<br /><br />I do know that hydrogen engines lose a lot more ISP<br />than Kero engines when operating at sea level air <br />pressure.

 

[j05h]

Totally forgot about SD being LOX-Kero. Can anyone suggest an appropriate, modern, commercially available engine that could do the job?<br /> <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[josh_simonson]

Wasn't sea dragon supposed to be pressure fed as well? That greatly reduces the task of designing engines for it.

 

[j05h]

yes, SD was designed as a massive, pressurefed TSTO. <br /><br />What would an updated Sea Dragon include? I think a drydock service structure that acts as launch platform might make sense. Cargo container handling capability and maybe the 2nd stage is designed to stay in space for use. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[gunsandrockets]

"What would an updated Sea Dragon include?"<br /><br />Choices that make sense for a large sea-launched TSTO launch vehicle include:<br /><br />1) Non-cryogenic propellants.<br /><br />2) One type of engine, four of which propell the first stage and one of which with a larger exhaust bell propells the second stage.<br /><br /><br />The orginal conception of the SeaDragon described over at astronautix.com uses LOX/RP-1 in the first stage and LOX/LH2 in the second stage. If liquid hydrogen is troublesome to handle in ordinary circumstances just imagine the nightmare of dealing with it at sea! Even liquid oxygen can be difficult as SpaceX has discovered with the recent mishaps of the Falcon 1 rocket. Now imagine instead of the LOX boiloff problems SpaceX was having with the Falcon 1 rocket in a warm tropic breeze, the boiloff problems a SeaDragon would have with the LOX tank under the waterline!<br /><br />The propellant choice that would most simplify sea-launch handling issues is probably nitric acid/RP-1. This is much less efficient than the cryo propellants, but the SeaDragon isn't about efficiency, it's about brute size. If the rocket has to be larger to compensate for the lower performing propellants, so what. (I admit that cryogenic propellants would have to be used for any 'Earth-Departure' third-stage. But since the size of the third-stage should be much smaller and sit high out of the water, that eases the pain. Plus maybe a warmer cryo combo such as LOX/CH4 could substitute for the classic LOX/LH2 combo.)<br /><br />Using the same propellants for both stages simplifies and reduces development cost. Another reduction of development cost is by using a cluster of engines on the first stage which are the same as the single engine used on the second stage. That way only one type of engine and of a smaller size has to be developed. The original SeaDragon used one giant engine per stage but of two different types, each type of different size as well as of differen

 

[barrykirk]

LOX may not be out of question for the first stage.<br /><br />First, put the LOX on top and the RP-1 on the bottom, this would keep as much of the LOX as possible above the waterline.<br /><br />Second, for the section of the LOX tank below the waterline, would it be possible to add some discardable insulation around that section of the LOX tank below the waterline.<br /><br />I agree that it would be bad to freeze large chunks of ice to a tank on a rocket.

 

[publiusr]

Sprague wan'ts an all LOX LH2 beast. Panels can come off the craft and take the ice with it--and the vibration would shake it loose from a coating of grease perhaps.<br /><br />More:<br />http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=1544&posts=8&start=1

 

[publiusr]

More here:<br />http://www.thespacereview.com/article/808/1

 

[Swampcat]

<font color="yellow">"You don't want to put grease anywhere near where LOX could reach it in even the worst accidental situation!"</font><br /><br />There are lubricants used in oxygen environments. <br /><br />Amateur rocketeers who use hybrid motors mostly use a product called Krytox for lubricating o-rings and screw threads.<br /><br />I believe it is also used in SCUBA gear. <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[docm]

Yup, and it has several automotive, medical & laboratory uses. <div class="Discussion_UserSignature"> </div>

 

[publiusr]

I wonder if it would work for tether/cables used to slice asteroids--Kursk style...