SR-71 continued from lunar hoax forum .

[Bozola]

Only if you don't have a grasp of the principles at play.

Dude, I wasn't trying to fluff your ego. I was, mistakenly as it turns out, attempting to be polite before I relegated you to the Ash-heap of Dribbling Idiots.

p.s., it's "pejoratives", not "pergoritives".

<font size=-1>[ This Message was edited by: bozola on 2002-08-27 10:23 ]</font>

[Kaptain K]

Thanks, Bozola.
I thought he had misspelled "prerogitives".

[SAMU]

Dribbling Idiot, spelling errors? Is that the best you could come up with, chat room childishness? I'm the one making the mistake of giving you more credit than that.
I'll try to make it simple enough for even a child like you to understand.
An object is falling down towards an imaginary flat plain with an acceleration of 1g. It also is moving at a constant straight line vector of 20,000 mph at a right angle to its direction of fall. The combination of the two vectors results in a curved path. In reality it is falling towards a curved plain that matches its curved path. that's called an orbit. At 1000 mph (which is a constant straight line vector) over the curved plain it is in fact accelerating at a right angle to its direction of movement at .05g.

[FP]

Anyone want to try this one, or is it a lost cause?

[Bozola]

[quote]
At 1000 mph (which is a constant straight line vector) over the curved plain it is in fact accelerating at a right angle to its direction of movement at .05g.
[quote]
Congratulations, you've just discovered centripetal force.

You'd better recheck those calculations because you're off by over a factor of 10.

Let us also not forget that this calculation is altitude (radius) dependent, not just speed, and it graphs as a curve.

[Firefox]

Now I'm curious as to how he thinks an airbreathing jet aircraft, with a low speed capability compared to a real spacecraft can achieve even a low orbit.


-Adam

[Kaptain K]

Anyone want to try this one, or is it a lost cause?

Definitely a lost cause. Not only does he not know what he is talking about, he is oblivious to his own ignorance.

Example: equating ballistic trajectory with sustained aerodynamically supported flight. SHEEESH!!! [img]/phpBB/images/smiles/icon_lol.gif[/img]

[SAMU]

The reduction in gravitational force acting on a object at at an altitude of 100 miles is little more than 2% of what it is at the surface.

The force I'm talking about (archaicly called centripetal or centrafugal (center pulling) ) amounts, at the speed the SR-71 is reported to be capable of (2200 mph or 10% of orbital speed), to a 10% reduction of the weight needed to be supported by aerodynamic forces.

Centripetal or centrafugal are words of convinience but archaic because they mean center pulling. In terms of gravitation an object is not "pulled" to the ground it is falling (accelerating) towards the center of gravity. If it is supported by the ground, the ground is pushing up with the same acceleration that it is falling down. If it is supported by the air, the air is pushing up with the same acceleration that it is falling down. If it is in orbit or with any percentage of orbital speed at a right angle to its fall towards the center of gravity then that percentage is canceled from its vector of fall.

Unless the replies get better than they have been for a while now, I'm gonna drop this thread.


<font size=-1>[ This Message was edited by: SAMU on 2002-08-27 18:09 ]</font>

[traztx]

On 2002-08-27 18:06, SAMU wrote:
The force I'm talking about (archaicly called centripetal or centrafugal (center pulling) ) amounts, at the speed the SR-71 is reported to be capable of (2200 mph or 10% of orbital speed), to a 10% reduction of the weight needed to be supported by aerodynamic forces.

It makes perfect sense that an object moving in the direction of the Earth's rotation will obtain an enhanced centripetal effect, (as long as the air is moving with the Earth). The angular speed at the equator is the highest. But isn't the atmosphere thicker at the equator? Would this cause an appreciable amount of extra drag?

[overrated]

Unless the replies get better than they have been for a while now, I'm gonna drop this thread.

Riiiiight... so it we don't make you the quarterback, you're going to take your ball and go home?

Look. Gramma loreto (and I, in an earlier post) pointed out how you've presented no evidence that the SR-71 is anything other than what it is. In fact, your SR-71 performance numbers demonstrate that it had neither the equipment nor the ability to attain escape velocity, a fact you keep sidestepping. On the other hand, the "SR-71 is a superfast aircraft" crowd has provided lots of arguments and evidence for why it isn't an orbital vehicle.

[Kaptain K]

Unless the replies get better than they have been for a while now, I'm gonna drop this thread.

Don't let the door hit you on the way out.

[SAMU]

traztx,

When you ask if the air is thicker do you mean denser or extends to a higher altitude at the equator. The sphere of the Earth is wider it the equator than it is at the poles (oblate sphereoid) so it extends higher above the center of gravity and mostly the atmosphere extends higher due to heat expansion there but is less dense than at the poles. But really the air moves in large masses of such widely varing thicknesses and densities and they move so chaoticly that a mass of certain thickness and density could be either at the equator or the pole.

But for the altitudes at issue here the air is so thin resistance is not a real issue. The real question is whether air at that altitude can be compressed by SR-71 ramjet enough to support sufficient combustion to produce enough thrust to overcome the resistance with enough extra to maintain acceleration long enough to achieve orbital velocity.
I have already posted the numbers and the numbers say it can. Regardless of what some of the "official" numbers say. The "official" numbers are inconsistant with themselves. While the "official" numbers can be truthfull in saying that the SR-71 can fly 2200 mph at an altitude of 85,000 ft. The Atlas spacecraft "can" also fly at 2200 mph at 85,000 ft. It can also fly faster than 2200 mph at more than 85,000 ft.

Here's a thought experiment for you.

An SR-71 is flying east towards Cape Kennedy at 30,000 ft fully fueled at 600 mph. At the cape an Atlas rocket is launched with an acceleration of .5g. The SR-71 flight path is coordinated to intercept the Atlas flight path at the moment the Atlas reaches 600 mph. At that time the SR-71 applies full power and accelerates at .5g and runs in parallel with the Atlas Until they both arrive at 2200 mph at 85,000 ft in air so thin that its resistance is only a fraction of what it is at lower altitude. SR-71 Remaining in the atmosphere only so low as to allow its engines to have enough air to burn its fuel and produce thrust. Issues of non aerodynamic control equipment and reentry heat disipation aside,(Many methods can be used I haven't mentioned before such as a "skipping" reentry.)The numbers say that it can achieve orbital velocity along with the Atlas. (or somewhat behind due to some additional air resistance from flying lower for longer compensated for with a longer burn.)


<font size=-1>[ This Message was edited by: SAMU on 2002-08-28 00:21 ]</font>

[Firefox]

The only problem is that the Atlas was a strategic intercontinental ballistic missile, intended to place objects into space and/or orbit. The SR-71 is a reconnaissance jet plane. Smells like a red herring to me, trying to compare the Atlas to the SR-71 and claiming that if the Atlas can mimic the SR-71's maximum thrust, then vice versa holds true.

I still want to know how the SR-71 would have been able to achieve orbital velocity, when its speed was well below that of the X-15s, and even that aircraft was insufficiently slow to reach orbital speed. Claiming the Blackbird can travel faster than mach 4 won't work, either, since it is well known what its speed capabilities are.

Try again, please.


-Adam

<font size=-1>[ This Message was edited by: Firefox on 2002-08-28 00:40 ]</font>

[GENIUS'02]

correct me if i'm wrong, but centrifugal forces DO NOT EXIST. the reason people experiance a "force" pulling them away from a turn is simply that momentum is a linear value and so works in straight lines only, thus when travelling in circles you feel like you are being pulled away from the centre of the turn by a force but realy you are just travelling in very small straight lines. no actuall force is pulling you away from the centre of the turn.
this is easily demonstrated using two people, a play ground, a roundabout (whatever they're are called where you live) and a ball. get one person to stand on the roundabout and spin around on it, then that person throws the ball away from the roundabout, so the ball flies away, now if centrifugal forces existed the ball would take a curved path away from the roundabout and the path would be easily calculated using trajectory mathematics linear velocity along one plane, and the force along another. However the ball does not curve it merely travvels in a straight line thus disproving centrifugal forces

at least thats what i think.

[jumbo]

Does any one know what size the SR71 fuel tanks are?
Why i ask is even if the SR71 could attain far higher speeds than officially claimed (a HUGE if,if you ask me) would it have enough fuel to sustain this type of flight?

Chip, i think X-15 number 3 had a stick that incoporate both aerodynamic controls and the RCS in one. So At altitude the control deflection would provide RCS control rather than altering the control surfaces, this was 'blended'with normal control depending on altitude. So im fairly sure the RCS was used.

The x-15 that was lost (again number 3)was destroyed during a mach 5 spin at 266000 feet. The pilot Michael Adams recovered a 118000ft but it went into a dive and broke up in mid air sadly killing the pilot.

Guess who bought x-plane just because you could fly the x-15 [img]/phpBB/images/smiles/icon_smile.gif[/img]

[Firefox]

Does any one know what size the SR71 fuel tanks are?
Why i ask is even if the SR71 could attain far higher speeds than officially claimed (a HUGE if,if you ask me) would it have enough fuel to sustain this type of flight?

According to FAS.org, the SR-71 has a range of 2000 miles, and carries 20 tons of JP-7 jet fuel. I would assume the 2000-mile figure comes from cruise range, since the Blackbird must refuel once it is airborne. As many probably know, the Blackbird leaks like a sieve on the ground, because the engineers could not develop an adhesive that would bond at such high temperatures. Only when she gets to altitude and into supersonic speed, that her tanks seal up and maintain integrity.

Still, 2000 miles isn't really enough to achieve orbit, especially when you factor the aircraft's limited speed capability compared to the Atlas.


-Adam

[SAMU]

Jumbo,
Fuel weight of SR-71 is 80,000 lbs. Compare to fuel weight carried by Atlas of 20,000 lbs liquid hydrogen and 175,000 liquid oxygen. And consider that the SR-71 picks up and uses for oxidizer the air in a ratio of 8 to one for oxidizer content and 4 to one for non combusting nitrogen reactive mass. In effect the SR-71 engines in burning all the fuel carried pass 2,560,000 lbs of fuel air mixture through them. while the Atlas passes only aprox. 200,000 lbs of hydrogen/oxygen.

GENIUS'02
You are correct. centrifugal forces DO NOT EXIST. What is being described by the term is mere acceleration. Classically defined is "any force that changes an objects condition of movement". Whether the condition of movement is "at rest" changed to "in motion", a linear force (acceleration) is needed. Whether the condition of movement is "in motion" changed to "faster motion, slower motion or at rest", a linear force (acceleration) is needed. Or if the condition of motion is changed in direction, as in the case of the so called "centrifugal force", again it is mere acceleration. All force is a linear vector. Any "force" that appears to be circular can be discribed as a combination of two or more linear vectors.

Firefox,
Your problem is that you seem to be having trouble understanding that an "intercontinental ballistic missile","jet plane" or for that matter parakeet, snowball or toaster that has the same acceleration and is moving in the same direction will continue to do so unless acted upon by an external force. The only external force existant in the scenario I have proposed is air resistance at an altitude where the air's density is so low that resistance/combustability is the only factor. Despite the official "speed" numbers released, thrust, weight and fuel capacity as well as altitude numbers released and other numbers say that resistance is low enough and combustability by ramjet compressive efficiency is high enough to allow the aircraft to continue to accelerate. (Mind you in a high altitude, near friction free, near vacuum environment.)

Regarding "leaking jet fuel". I have long suspected that that is mere romatization. While I have never seen an SR-71 fully fueled and ready for takeoff. Neither have I seen film of the SR-71 covered in jet fuel or in a puddle of jet fuel or engulfed in flame when the flame from the engines ignite said jet fuel.

<font size=-1>[ This Message was edited by: SAMU on 2002-08-28 12:16 ]</font>

[Darkwing]

Firefox,
Your problem is that you seem to be having trouble understanding that an "intercontinental ballistic missile","jet plane" or for that matter parakeet, snowball or toaster that has the same acceleration and is moving in the same direction will continue to do so unless acted upon by an external force. The only external force existant in the scenario I have proposed is air resistance at an altitude where the air's density is so low that resistance/combustability is the only factor. Despite the official "speed" numbers released, thrust, weight and fuel capacity as well as altitude numbers released and other numbers say that resistance is low enough and combustability by ramjet compressive efficiency is high enough to allow the aircraft to continue to accelerate. (Mind you in a high altitude, near friction free, near vacuum environment.)

You're forgetting an important force with regards to the SR-71. It's called "lift."

[SAMU]

Darkwing,
The proposition is that as the aircraft goes higher the air gets thinner and less able to support it with "lift". But the air also becomes less able to resist its velocity and as velocity increases a smaller portion of the weight of the aircraft needs to be supported by "lift" and is "supported" by linear movement relative to the curved surface of the Earth. Basically described as using thrust to effect a transition from "aerodynamic lift" to maintain distance from the surface (altitude)to a "ballistic trajectory" to maintain distance from the surface (altitude). Whereas for comparison the Atlas uses thrust to effect a transition from "at rest" on the ground to a "ballistic trajectory" at altitude.

[traztx]

On 2002-08-28 00:16, SAMU wrote:
When you ask if the air is thicker do you mean denser or extends to a higher altitude at the equator. The sphere of the Earth is wider it the equator than it is at the poles (oblate sphereoid) so it extends higher above the center of gravity and mostly the atmosphere extends higher due to heat expansion there but is less dense than at the poles. But really the air moves in large masses of such widely varing thicknesses and densities and they move so chaoticly that a mass of certain thickness and density could be either at the equator or the pole.

So since the atmosphere extends farther out, an aircraft could gain more altitude near the equator, right?

Also, I think people shouldn't completely dismiss ballistic effects on moving objects. Just because an object has wings doesn't mean it no longer has momentum.

As for going into orbit... if I were to assume they secretly did it, wouldn't I have to consider reentry and burning up? Did the craft have the proper protection from reentry?

[Valiant Dancer]

On 2002-08-28 11:42, SAMU wrote:
Jumbo,
Fuel weight of SR-71 is 80,000 lbs. Compare to fuel weight carried by Atlas of 20,000 lbs liquid hydrogen and 175,000 liquid oxygen. And consider that the SR-71 picks up and uses for oxidizer the air in a ratio of 8 to one for oxidizer content and 4 to one for non combusting nitrogen reactive mass. In effect the SR-71 engines in burning all the fuel carried pass 2,560,000 lbs of fuel air mixture through them. while the Atlas passes only aprox. 200,000 lbs of hydrogen/oxygen.