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  #41  
Old 02-08-2011, 06:26 PM
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Bill,

I have learned over the years that I'm not building anything until something actually flys. Shenzhou, Soyuz and Dragon have actually flown and all will fly again this year.

Everything else are just fancy earmarks . . . .

Painting has started on the Soyuz and I am going to try the screens Sandman is sending.

Pictures soon.
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  #42  
Old 02-13-2011, 01:07 AM
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Quote:
Originally Posted by Bill
Uh oh or oh joy depending upon how you look at it, but you may have many more vehicles to build: http://groups.yahoo.com/group/scaleroc/message/13247


Bill



Yeah, I'll believe that when I see it...

Brought to you by the same folks who came up with "Safer, Simpler, Sooner..." Yeah right! Six billion spent on Ares I, all to show for it was a stack of engineering problems out the gazoo for an underpowered booster that would shake the capsule like a paint shaker and a "test flight" with a four segment shuttle booster with a dummy fifth segment, a battleship interstage, topped by a "tuna can" dummy upperstage and boilerplate BPC and LAS which were both of an outdated earlier design...

This "Liberty launcher" doesn't look any more realistic or than the Ares I... and anybody that's followed the discussions of Ares I problems will tell you that this thing is going to have serious problems... The main reason that the Ares I switched to the five-segment first stage solid rocket motor instead of the standard four-segment Shuttle SRB that it was initially designed with, was because of the switch from the SSME for the second stage to the J-2X second stage liquid rocket engine. The SSME would be fairly difficult to re-engineer for an airlit engine, since it was designed to be groundlit for space shuttles, and more importantly it would be virtually impossible to redesign for multiple restarts, which would be essential on Ares V for the EDS upper stage to reignite for Trans-Lunar Injection or Trans-Mars Injection. In the early stages, SSME was to fill this role. Once it became obvious SSME would be impossible for Ares V, J-2S became a necessity. Once that design change filtered down, and the costs for J-2S were realized, J-2S supplanted SSME-airstart for the second stage of the Ares I, to eliminate the costs of maintaining a third engine line for the Ares I/V vehicles, and to share costs between Ares I and V. Once the performance data had been calculated, it became apparent that J-2S was simply underpowered for the upperstage of Ares I-- it's thrust was simply too low, which left a few possibilities-- install TWO J-2S engines on the upperstage (which cuts into safety numbers having more engine airstarts) or go to a bigger first stage SRM, or a higher thrust J-2 variant, or both. The shuttle four-segment SRB was out, and the five segment "Ares V" SRB took it's place as the first stage of Ares I, and the up-powered J-2X replaced the J-2S which was initially baselined, even though the upgrades necessary for upgrading the power on the J-2X meant that basically the entire engine had to be designed from scratch, as the J-2S turbopumps weren't really designed for the job.

Ares I went downhill from there.

The SSME is a 490,000 pound/thrust engine. The Vulcain 2 used on the Ariane 5 is a 300,000 pound/thrust engine. While this is SLIGHTLY better than the 290,000 pound thrust J-2X (and somewhat better than the 256,000 pound thrust J-2S) the thrust is not remarkably better. Also the Specific Impulse of the Vulcain 2 is only 431 seconds, which means it'll take more fuel (weight) to do the same work than the slightly better ISP of the J-2X, (supposedly listed as 448 seconds, but I've heard that it's not meeting it's performance goals, so probably closer to the J-2S's ISP of 436 seconds, which is closer to but still higher than the Vulcain 2). Both are woefully short of the SSME's 453 second ISP. This means that the this "Liberty booster" will suffer from the same problems as Ares I fundamentally did-- the first stage is undersized for the job it has to do- it stages too low and too slow, leaving the upperstage to do more work than it should. The second stage REALLY needs an SSME class thrust engine to overcome gravity losses from staging so early at the lower speed. The lower thrust engine means higher gravity losses, which means MORE fuel is required to achieve orbit than would otherwise be necessary. More fuel equals more weight for fuel and tankage, more weight equals more gravity losses, and the lower ISP doesn't help either, though more thrust is really more important in this application.

Then there's going to be the whole issue of putting an Ariane 5 core stage ON TOP of an SRB, an arrangement it was NOT designed for. The load paths and bending moments will be SIGNIFICANTLY different than those experienced by the Ariane 5 in it's presently designed arrangement with a pair of flanking SRB's. In addition, the Vulcain 2 will have to be redesigned for airstart, because, like SSME, the Vulcain on Ariane 5 is groundlit before liftoff. All that redevelopment will cost money, and lots of it. Then there's the problem with the SRB cases... the SRB case from the Ares I-X test flight was bent beyond reuse. There are only SO many shuttle SRB casings, and they aren't being made anymore. AFAIK, NASA owns them all, and I doubt they're going to just let some "commercial company" use them willy-nilly for their own "commercial rocket", especially when the current designs for shuttle derived heavy lift rockets for the Space Launch System which has been enacted by Congress to replace the cancelled Constellation Program's Ares I and Ares V rockets, will use SOME form of shuttle-derived SRB (currently all variants call for the five-segment SRB being developed for Constellation to be used, as ATK is strongarming the government by saying they scrapped everything needed to make more four-segment shuttle boosters in favor of the five segment Constellation boosters, and thus it will cost just as much for them to make four segment shuttle-type boosters in the future as it would for five-segment Cx type boosters). Any launch or recovery failure (like Ares I-X) would mean the loss of a set of finitely-available booster casings, which NASA may end being in short supply of.

While NASA is currently planning to spend a fortune updating KSC into a "21st Century Spaceport" and already has the Ares I MLP built and currently probably headed for the scrapyard, (unless another use can be found for it) and while this would be ideally suited for such an SRB first-stage type booster like Liberty, and while NASA is looking for 'renters' to use KSC for commercial launches to utilize the infrastructure and create some badly needed revenue, it's also a terribly expensive architecture to keep maintained and used and those costs WILL be passed on in some form to whatever commercial 'renters' of KSC that come along. That's why the EELV launchers have gotten away from the pad integration of the early Saturn I's and Ib's and the VAB/crawler vertical integration and vertical transport on MLP to the launch pad like Saturn V, later Ib's, and Shuttle has used, and copied the Russian horizontal integration and rail tranport to the pad operations model.

Then there's the operating environment-- riding on top of an SRB is a VERY rough ride, as the vibro-acoustics studies on Ares I were proving, which required a sophisticated and expensive (and heavy, cutting into cargo to orbit performance) vibration mitigation program to keep the rocket's upper stage and payload from vibrating to pieces. The shuttle survives this because the thrust beam connecting the two SRB's to the ET is beneath the heavy LOX tank and flexes and bends up to six inches in flight, acting like a giant shock absorber or car spring to absorb most of the vibrations. There is no such shock absorbing beam when the upperstage is ON TOP of the SRB... I've seen some of the mitigation strategy-- gigantic "C" shaped vibration isolators, arranged in pairs around the interstage to absorb the punishing vibrations... I severely doubt Ariane 5's core stage is designed for this either, or the aero loads of being used as an upperstage on top of an SRB.

I can see about a dozen ways to Sunday why this idea is pretty poor... There was an early design for a "Cargo" Ares I, capable of launching a "Cargo Orion" or even a stripped cargo canister to the ISS using an Ares I... it was soon scrapped once the costs of Ares I started to become apparent. I don't see how this Liberty booster can possibly be much cheaper-- SRB's and their infrasturcture is EXPENSIVE, which is why the EELV's don't use LARGE SRB's... only smaller ones...

Later! OL JR
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  #43  
Old 05-21-2011, 06:41 PM
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Guys, (and Gals, if any actually visit this site),

I did finish the builds but I realized I never sent a picture.

So here they are: Vostok and Soyuz with my old Alpha along for scale.

Thanks to Carl (Semroc) and Sandman (Roachwerks) for the supplies, Peter Alway for the original plan and all the people who responded to this thread with ideas or encouragement.

I'm ready to do a Shenzhou, Falcon/Dragon and a Proton/Zond in more or less the same scale as soon as we can buy the stuff off the Semroc Nose Cone Designer.
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Awaiting First Launch: micro V-2; Blossom V-2; Aero-Dart; TLP Hellfire
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Repair/Rescue: Eggspress, Centuri Stilleto
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  #44  
Old 05-22-2011, 01:08 AM
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Quote:
Originally Posted by MarkB.
I'm ready to do a Shenzhou



Did you manage to score that plastic kit?


Bill
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  #45  
Old 05-22-2011, 09:07 AM
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As a matter of fact I did! John at Hudson Classic Hobbies took good care of me. I was able to score both the CZ-2E and CZ-2F plastic kits in 1/48th scale. What I'm going to do with two giant Chinese rocket kits after I've measured them to make a slightly smaller flying kit remains a mystery. At over a meter tall, they make lousy bookends.

In any event, I am going to post that build with measurements starting next month and I'll build it up to the payload section in anticipation of the Semroc nose cone being available sometime after that.
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Identifying a problem without proposing a solution is just whining.

NAR 79743
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SAM 062

Awaiting First Launch: micro V-2; Blossom V-2; Aero-Dart; TLP Hellfire
Finishing: Zooch Saturn V; Tomahawk sustainers (3!)
Repair/Rescue: Eggspress, Centuri Stilleto
On the Bench: Atlas V 541;
Dream Stage: 1/39.37 R-7
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  #46  
Old 05-22-2011, 11:13 AM
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Quote:
Originally Posted by MarkB.
As a matter of fact I did! John at Hudson Classic Hobbies took good care of me. I was able to score both the CZ-2E and CZ-2F plastic kits in 1/48th scale. What I'm going to do with two giant Chinese rocket kits after I've measured them to make a slightly smaller flying kit remains a mystery. At over a meter tall, they make lousy bookends.



There is only one thing you can do...PMC...


Bill
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It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
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  #47  
Old 05-22-2011, 06:21 PM
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Quote:
Originally Posted by MarkB.
As a matter of fact I did! John at Hudson Classic Hobbies took good care of me. I was able to score both the CZ-2E and CZ-2F plastic kits in 1/48th scale. What I'm going to do with two giant Chinese rocket kits after I've measured them to make a slightly smaller flying kit remains a mystery. At over a meter tall, they make lousy bookends.

In any event, I am going to post that build with measurements starting next month and I'll build it up to the payload section in anticipation of the Semroc nose cone being available sometime after that.


Put 'em on Ebay as "museum quality" built models for $1499.95 Buy it now??

LOL Later! OL JR
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  #48  
Old 05-25-2011, 11:01 AM
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Quote:
Originally Posted by MarkB.
Guys, (and Gals, if any actually visit this site),

I did finish the builds but I realized I never sent a picture.

So here they are: Vostok and Soyuz with my old Alpha along for scale.

Thanks to Carl (Semroc) and Sandman (Roachwerks) for the supplies, Peter Alway for the original plan and all the people who responded to this thread with ideas or encouragement.
Thanks for the pics Mark. This thread will be a great reference if/when I ever build a Vostok.
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  #49  
Old 05-25-2011, 01:03 PM
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Here are some colour reference drawings.
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File Type: pdf A05172-BC.pdf (55.7 KB, 51 views)
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