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Why does SS1 need the drag configuration?

Posted by: roygrif - Mon Aug 02, 2004 8:15 pm
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Why does SS1 need the drag configuration? 
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Post    Posted on: Tue Aug 10, 2004 8:54 pm
SR-71... the Skunk Works...


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Post    Posted on: Wed Aug 11, 2004 12:52 am
SawSS1Jun21 wrote:
SR-71... the Skunk Works...


:shock: :oops: Uh, yeah. I knew that. Very very definitely the same category. ::mentally reviews Skunk Works projects:: Yeah, same category.

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Post    Posted on: Tue Sep 21, 2004 5:50 pm
:shock:

Odd how people's perceptions can vary. Rutan is a great designer, so was Jack Northrop. Von Braun might even be considered in the same list (although it's a little different in his case).

But Kelly Johnson is just...the ultimate plane designer. Hell, the only person who I'd even put in the same league would be the Wright Brothers, and everyone else can go jump :)

That said, only one of the above is still designing planes, and who knows where he might end up if it all goes according to plan. Rutan might make himself a very large chunk of history if this all goes right - and I certainly hope it does.

Umm, back on topic although it has mostly been said, SS1's feathered combination was to increase drag early on so that it's decceleration time was extended, and so the maximum amount of force being put on the plane was reduced.

The X-15 used a special type of metal called Inconel-X, which is a special high-temperature metal. It acted very much like the heat-shielding tiles on the Space Shuttle, and was about as difficult to manufacture. They had to be cast molded for each of the various wing sections, and were (As far as I know) the single most expensive part of the whole project, since an entirely new manufacturing process had to be invented to produce them. By comparison, feathering is very simple and elegant.

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Post    Posted on: Tue Sep 21, 2004 6:52 pm
In this case, does SS1 generate enough drag to slow down enough to use SS1 as a lifeboat foor the ISS?


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Post    Posted on: Tue Sep 21, 2004 9:17 pm
siggy wrote:
In this case, does SS1 generate enough drag to slow down enough to use SS1 as a lifeboat foor the ISS?


No, it does not have proper heat shielding.


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Post    Posted on: Wed Sep 22, 2004 8:26 am
The relevant problem seems to be the difference that the ISS has orbital velocity but SS1 "suborbital" velocity.

So it might be sufficient if someone finds a way to decelerate from ISS-velocity down to SS1-velocity BEFORE reentry.

There is a at least theoretical possible way discussed in other threads around the cables of the space elevator. This possible way form my point of view seems to provide a "next evolutionary step".

May be this way and other ideas can be combined to decelerate from Mach25 down to Mach3,5.

...



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Post    Posted on: Wed Sep 22, 2004 3:45 pm
Spaceship one only has to bleed of a fraction of the energy that a full orbital re-entry vehicle would.

Consider the speeds: Spaceship one, on re-entry, peaks at slightly over mach 3. I believe the number was mach 3.2, or about 1050 ms-1. An orbital re-entry occurs at closer to mach 24, or 8000 ms-1 (it varies depending on exactly what orbit you make, and can be as low as 7000 or as high as 10000).

So how much energy do these two situations need to get rid of in order to land?

KE = 0.5 * mass * velocity^2
We'll ignore the two constants for now, and focus only on the velocity, since the mass would vary depending upon your vehicle.

1050^2 = 1,100,000
8000^2 = 64,000,000

So in order to re-enter from an orbital flight, you have to dissipate about 60 times more energy than from a suborbital flight. This is also why SpaceshipOne isn't even remotely powerful enough to get into orbit.

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Post X-15   Posted on: Wed Sep 22, 2004 8:05 pm
SpaceShipOne uses the rotating tailbooms to eliminate the potential for an uncontrolled spin of the kind that killed Mike Adams.

The X-15 entered at a high drag angle like SpaceShipOne, but used a combination of reaction control jets and aerodynamic control surfaces to achieve it and thus did not have the built-in stability of SpaceShipOne.


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Post    Posted on: Thu Sep 23, 2004 7:31 am
Hello, Sev,

I don't know wether you were responding to my post. I know the numbers but I could imagine that the required deceleration can be achieved by catapulting SS1 backwards from the ISS - via tethers spinning around. Perhaps this has to take place several times before reentry and is to combined to other methods.

What are the reasons why this should be impossible?



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Post    Posted on: Fri Sep 24, 2004 8:39 pm
JustMeKevin wrote:
*heh* Yeah. Thus the company name Scaled Composites. I assume Voyager was made of the same (or similar) materials.


Similear in the sense of non-metallic, but the whole idea with SSO is to provide heat resistance (plus, carbon composite construction has become standard with rutans planes), whereas the with the voyager they were trying to get as a rediculessly light a plane as possible (speaking of the voyager, I have the book about them signed by both dick rutan and jean yeager! 8) ).

The voyager was an amazing plane, and a break from the military's regime of the best planes around. Almost reminds me of the Wright Flyer, just a few backyard mechanics changing the world.

SawSS1Jun21 wrote:
SR-71... the Skunk Works...

Hell yea! U-2 spyplane, SR-71 highest fastest plane on the planet, F-117 stealth 'revolution', uh F-104 tiny superfighter, P-30 first real jet fighter, you name it, they made it! They even have a stealth boat that owned frigates, cost about half the money and like a tenth (or less) of the crew!

These people are like GODS to me.


Anyway, after reading this rideculessly long thread, I have to ask you all why you are linking the SSO with the X-15? The X-15 provided the foundations for the very begining of space aviation, but when you start picking at details its really quite different. Like rutan and a few other guys here were saying, the X-15 was supposed to explore the outer limits of how fast planes can go. I have a feeling it was one of those buisnessmen sitting at a desk and asking each other "hey, lets build an aircraft that will go as fast as humanly possible!" Fun as hell, and quite amazing concidering the Bell X-1 first made supersonic flight, what, less than a decade ago?

But the SSO is designed to shoot up into space and then come down without killing itself. Its not at all meant to go at ludicris hypersonic speeds, and its entire aerodynamic construction is meant to avoid those hypersonic re-entry speeds, completely seperating itself from the X-15.

Also, you guys are thinking about this thing getting scaled up. Right now its an engenius little 'badmitten' (as somebody referred to as it before) that floats down perfectly, but the top number of people you can get inside one of these things is like 30 or so, after a while it really just gets bulky and unrealistic. When you get like a 5 foot birdie to play basket ball with, the concept starts losing its appeal. If you wanna throw hundreds of people from one side of the planet to another in half an hour or so, you wanna start looking into the NASP or somethin big jet plane that goes into space. Actually, I'm formulating my own design of a large space shuttle that would carry cargo and people into space on a very in-expensive and re-usable basis. I may make a thread later once I have a significant number of sketches.

EDIT: somewere someone (maybe even himself) mentioned rutan was using a donated starship. Didn't he MAKE the starship? Or at least mentor the concept / design? A bit ironic if you ask me... Kinda shows that leading the world in space travel doesnt pay like you might think it would.

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Post    Posted on: Sat Sep 25, 2004 3:30 pm
mwace wrote:
EDIT: somewere someone (maybe even himself) mentioned rutan was using a donated starship. Didn't he MAKE the starship? Or at least mentor the concept / design? A bit ironic if you ask me... Kinda shows that leading the world in space travel doesnt pay like you might think it would.


SpaceDev made the hybrid motor, http://www.spacedev.com/newsite/templates/subpage_article.php?pid=488
Other than that I'm pretty sure both SpaceShipOne and WhiteKnight are entirely designed and built by Scaled.


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Post    Posted on: Sat Sep 25, 2004 5:35 pm
Rubbernecker wrote:
mwace wrote:
EDIT: somewere someone (maybe even himself) mentioned rutan was using a donated starship. Didn't he MAKE the starship? Or at least mentor the concept / design? A bit ironic if you ask me... Kinda shows that leading the world in space travel doesnt pay like you might think it would.


SpaceDev made the hybrid motor, http://www.spacedev.com/newsite/templates/subpage_article.php?pid=488
Other than that I'm pretty sure both SpaceShipOne and WhiteKnight are entirely designed and built by Scaled.


Nono, the beechcraft starship!

Image

Its got the rutan style design, modeled after the Long EZ, the plane is manufactured by Beechcraft, but the design undeniably fathered by rutan.

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Post    Posted on: Sun Sep 26, 2004 9:45 am
mwace wrote:
Anyway, after reading this rideculessly long thread, I have to ask you all why you are linking the SSO with the X-15? The X-15 provided the foundations for the very begining of space aviation, but when you start picking at details its really quite different. Like rutan and a few other guys here were saying, the X-15 was supposed to explore the outer limits of how fast planes can go. I have a feeling it was one of those buisnessmen sitting at a desk and asking each other "hey, lets build an aircraft that will go as fast as humanly possible!" Fun as hell, and quite amazing concidering the Bell X-1 first made supersonic flight, what, less than a decade ago?

But the SSO is designed to shoot up into space and then come down without killing itself. Its not at all meant to go at ludicris hypersonic speeds, and its entire aerodynamic construction is meant to avoid those hypersonic re-entry speeds, completely seperating itself from the X-15.


The point is that despite this, they both achieved very similar goals - the maximum height achievable for both was very similar, even if limited by different things. Otherwise, they both achieve pretty much the same thing - suborbital flight - through similar means - being dropped by a carrier aircraft and then using their own rocket engines to propel them. Yes, the reasoning behind the two planes was radically different, but in the end they have more similarity than say, SS1 and Wild Fire (the Da Vinci project's rocket).

Oh, and they're both awesome planes :)

Quote:
Also, you guys are thinking about this thing getting scaled up. Right now its an engenius little 'badmitten' (as somebody referred to as it before) that floats down perfectly, but the top number of people you can get inside one of these things is like 30 or so, after a while it really just gets bulky and unrealistic. When you get like a 5 foot birdie to play basket ball with, the concept starts losing its appeal. If you wanna throw hundreds of people from one side of the planet to another in half an hour or so, you wanna start looking into the NASP or somethin big jet plane that goes into space. Actually, I'm formulating my own design of a large space shuttle that would carry cargo and people into space on a very in-expensive and re-usable basis. I may make a thread later once I have a significant number of sketches.


I'd agree that none of the current proposals seem very likely for a decent method of getting people into space. There is certainly no point in using an air-breathing engine to get into space, so you might as well stick it to the back end of a rocket.

The problem with making a passenger carrying Space Shuttle is still the launch costs. Even if you crammed 40 people into one, it would still be more expensive per person than just sticking them in a Soyuz. The Space Shuttle is an awesome piece of technology, but frankly, for getting things into space it is horrendously inefficient. The only way it can even compete commercially is through aid from the government.

Ekkehard Augustin wrote:
I don't know wether you were responding to my post. I know the numbers but I could imagine that the required deceleration can be achieved by catapulting SS1 backwards from the ISS - via tethers spinning around. Perhaps this has to take place several times before reentry and is to combined to other methods.

What are the reasons why this should be impossible?


Yes and no. Tethers are realistic yes, but not from the ISS. Using the ISS to fling anything down to Earth would result in the ISS being shot off to mars or something equally bad.

As for using a tether to help something re-enter, yes that is perfectly feasible. The downside of course if that the cost of a tether would be enourmous, and it's not going to be worthwhile until we have a fully fledged space industry (I mean, a BIG one. A space tether, even using "future technologies", would cost over $100Bn - and probably much more than that)

Also, tethers would first be used to get things into orbit anyway, since it is actually still harder to get something up than down.

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Post    Posted on: Sun Sep 26, 2004 5:02 pm
Concerning the material the tether to make of i was thinking of - no wonder - nanocarbontubes. The recent use may mean, that they will be produced within ten years and at costs much less then 100 billion dollars. Only one squaremeter 10 nanometers thick of material is required to produce one single cable by the method reported by an article I mentioned in another thread.

It would be possible to install a spinning tether at the ISS in a manner that the ISS will not be catapulted out of its orbit I think.


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