SR-71 continued from lunar hoax forum .

[SAMU]

If you will note that picture shows an air craft in flight not sitting on the ground leaking fuel. It shows as you will note a "fluid" in low pressure areas of the aircraft. Subject a volume of air with evaporated water content to a sudden drop in pressure as those zones will do and the water will condense on any surface or even on itself if the moisture content is high enough. I don't know that that is what is happening here but this picture does not satisfy me regards leaking fuel as an alternative explanation is available.


One more point to spark your imagination: Since the US has SR-71 wouldn't the Russians also have some of their version? Maybe more, since their usual strategy was to steal our research and save on development costs and put the savings in building greater numbers. I wonder what a surplus Russian SR-71 could be had for. Kid Rock or whatever that rock kid's name is who wants to go up on a Russian rocket should take note.

<font size=-1>[ This Message was edited by: SAMU on 2002-08-28 18:04 ]</font>

[jumbo]

The SR71 does leak on the ground or at least it looks like it. I saw one before a flight a few years ago and it was having a good go at leaving as much mess as it could before it left.

[overrated]

The SR-71 does leak fuel on the ground. JP-7 has a high ignition point; you could toss a lighted cigarette into it and nothing would happen. It presents very little risk of ignition.

And the Russion version of the SR-71, speedwise, at least, was the MiG-25, which held the world speed record (briefly). It was an interceptor, though, not a recon plane. Its standout characteristic was its design--it used no exotic materials and was relatively cheap; however, the engines had to be replaced after flights above Mach 3. The aircraft also had an incredibly powerful radar system (that Russian technicians say they observed kill small animals when it was activated on the ground), but overall, it wasn't maneuverable or a very effective weapons platform. It's overrated capabilities are what triggered the United States' F-15 program.

(see http://www.mobiledyne.com/pub/j58.html for JP-7 specs in layman's terms)

_________________
PC load letter? What the @%$# does that mean?

<font size=-1>[ This Message was edited by: overrated on 2002-08-28 18:52 ]</font>

<font size=-1>[ This Message was edited by: overrated on 2002-08-28 19:06 ]</font>

[SAMU]

One thing I have been noticing about the "flight manual" of the SR-71. The more I read it the more it looks like a pilot rating manual than an aircraft performance manual. What I mean is; say they are going to release a flight manual and say that there are several levels of rating pilots of the SR-71 could attain. For example a 1500mph 45,000ft rating, a 2200mph 85,000ft rating or an orbital rating. If what we have here is a rating manual for a 2200mph 85,000ft pilot it would resemble a perfomance manual in many respects but it has operational orders in it more resembling rules than limits. For example this page
http://www.sr-71.org/blackbird/manual/5/5-10.htm
says "The maximum altitude limit is 85,000 ft unless higher altitude is specifially authorized". If 85,000ft was a maximum performance altitude then who would a pilot go to for "authorization"? God? As well it gives prohibition rules such as no stalls, spins, inverted flight and so forth.
The point is if a "driving manual" says "the maximum speed limit is 60 mph" it doesn't mean that all cars are mechanically capable of going only 60 mph.

[Firefox]

If you will note that picture shows an air craft in flight not sitting on the ground leaking fuel. It shows as you will note a "fluid" in low pressure areas of the aircraft. Subject a volume of air with evaporated water content to a sudden drop in pressure as those zones will do and the water will condense on any surface or even on itself if the moisture content is high enough. I don't know that that is what is happening here but this picture does not satisfy me regards leaking fuel as an alternative explanation is available.

Say what you will. The most logical explanation, given the development history of the Blackbird, is that you're looking at leaking fuel.

One more point to spark your imagination: Since the US has SR-71 wouldn't the Russians also have some of their version? Maybe more, since their usual strategy was to steal our research and save on development costs and put the savings in building greater numbers. I wonder what a surplus Russian SR-71 could be had for. Kid Rock or whatever that rock kid's name is who wants to go up on a Russian rocket should take note.

Another red herring. Stick to the subject, please.


-Adam

[overrated]

On 2002-08-28 18:59, SAMU wrote:
One thing I have been noticing about the "flight manual" of the SR-71. The more I read it the more it looks like a pilot rating manual than an aircraft performance manual. What I mean is; say they are going to release a flight manual and say that there are several levels of rating pilots of the SR-71 could attain. For example a 1500mph 45,000ft rating, a 2200mph 85,000ft rating or an orbital rating.

Ohmigosh. You're making stuff up again. Flight manuals aren't designed that way. I own some. They describe the flight characteristics and systems of the aircraft--which that SR-71 manual does. The 85,000-foot altitude is its service ceiling, the altitude that test flights have shown is the maximum it can always be completely controlled. The same goes for stall speeds, turn radii, etc.

And the authorization to exceed that ceiling would come from a superior officer. It's the military. Sheesh.

[SAMU]

A cigarette wouldn't start a fire even in gasoline. And an airplane can make quite a mess on the ground during normal (non leaking) operations, fuel spillage, hydraulic fluid spillage and you should see the mess just from clearing the fuel tank condensation valves and if you move the aircraft before you chech the valve it is ten times worse. I wasn't the one to bring up the "red herring" about leaking fuel. I just wanted to get on the record my own opinion about it.

[overrated]

So what was your opinion? That the SR-71 doesn't leak when it's on the ramp? That the leaking fuel could be ignited on the ground? Both statements are false. Just for the record.

[DogB]

On 2002-08-28 00:16, SAMU wrote:
traztx,
...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>

SAMU

What you consistently fail to recognise is that your initial premise is severely flawed. Rocket powered vehicles accelerate faster the higher they go. This is due to fuel burnoff and the reduction in atmospheric drag. Air breathing craft also gain speed the higher they go…..to a point!!!! The efficiency of an air breathing craft begins to drop off as the air thins to a point where it will no longer sustain the combustion. The thin air also provides less lift and the stall speed goes up significantly. As this occurs and the craft slows due to decreasing engine power the aircraft reaches its service ceiling.

So to get back to your experiment. Our Atlas and our blackbird reach 2200mph (ground speed) at 85,000 ft. Both craft throttle up to max power. The Atlas is still producing its full rated thrust and continues to accelerate faster and faster as the air thins until it reaches orbital velocity. The Blackbird is already at its operational ceiling and close to maximum speed. So the pilot sticks the nose up and the bird begins to climb. As it climbs the air thins, the engines begin to run less eficently, the power begin to drop off, the airspeed falls and eventually the craft will stall and fall (probably with two flamed out engines).

The Blackbird is great plane, a masterpiece of engineering but it’s still just an aircraft. Based on your theory I should be able to get tiger moth into space as long as I can carry enough fuel [img]/phpBB/images/smiles/icon_smile.gif[/img]

Dog

(edited to make more friendly, I forgot what board I was on)



<font size=-1>[ This Message was edited by: DogB on 2002-08-28 22:21 ]</font>

[GENIUS'02]

ok heres status report with couple of pictures on the SR-71:

http://www.vam.smv.org/sr71statusold.html

heres a page all about air-things ( only starting with the letter S)4 or 5 topics on the SR-71

http://www.ameijer.demon.nl/airlinks/air-s.htm

SR-71 one refueling (hmmmmn whats that liquid)

http://www.sr-71.org/photogallery/bl...ted/rod-03.jpg





<font size=-1>[ This Message was edited by: GENIUS'02 on 2002-08-28 22:51 ]</font>

[Bozola]

Excellent photo of the refueling, Genius.

....Subject a volume of air with evaporated water content to a sudden drop in pressure as those zones will do and the water will condense on any surface or even on itself if the moisture content is high enough....

Bwaaaaaahahaha. OKay. Never mind that refueling happens typically between 25,000 - 30,000ft, at a minimum of 300 KEAS. Never mind that you think it could be liquid water in those conditions.

Here's a question: What happens to water vapor when the pressure drops "suddenly" and it hits it's condensation point?

Here's a hint: What do you see?

Here's another hint: Why does the US military carefully monitor "water conditions" at high altitude?

[GENIUS'02]

ok heres more info from another SR-71 website,

http://www.blackbirds.net/sr71/successortou2.html

another picture dman its such an .... hmmmnnn.... aircraft.

http://chanae.stben.be/pub/images/air/sr71a.gif

[Gramma loreto]

On 2002-08-28 19:12, SAMU wrote:
A cigarette wouldn't start a fire even in gasoline.

Gasoline...probably not. Gasoline vapors (which are virtally always present at average sea-level pressure and humidity)...you bet your tailpipe a cigarette will do it.

And an airplane can make quite a mess on the ground during normal (non leaking) operations, fuel spillage, hydraulic fluid spillage...

There is often a big difference between static leaks and those that occur under pressure. An aircraft may not leak (much) when it's just parked on the ramp but when you pressurize the system (fuel or hydraulics), leaks occur more often. Static leaks usually (but not always) get worse when the system is under pressure.

...about leaking fuel. I just wanted to get on the record my own opinion about it.

Your opinion is uninformed. While I'm no expert on the SR-71, I maintained fighter aircraft for 12 of my 20-plus-year career in the Air Force, so I'm quite familiar with many models of military aircraft. I've worked with and spoken to others who did work on the blackbird. I've even observed more than a couple of SRs on the ramp and while taking off. They leak. Deal with it.

[SAMU]

Just thought I'd add what I call a hands on illustration of density variation. Make of it what you will. (I'm sure some of you kids will trash it as much as you can.)

Iron is 7 times denser than Water. Hold some Iron in one hand and some Water in the other. Heft them in your hands, feel how much more energy one requires to move than the other. Imagine a ship moving through Water, pushing aside the water in its path. Now imagine the ship pushing its way through... But iron is solid and you can't move through it. But you can move through Mercury. Mercury is 13.5 times denser than Water. But you probably aren't going to have the chance to have a good handfull of Mercury to play with. Get ahold of some Lead instead. It is only 11.3 times denser than Water but is a lot easier to get. If you have the means check out some Gold. Its density is 18.8 times that of Water. Although you wouldn't want to touch it you can compare it to Uranium at 18.9 times denser than Water. You might be able to get a hand on some Tungsten at 19.3. Over that almost everything else in my list is radioactive. Plutonium, 19.8 ?Neptunium?...20.4. Platinium 21.4. (If you could spare a hand full of that send it ot me, I'd like to test my theory on that one myself) And the densest element in my list which is Iridium at a whopping 22.4 times denser than Water.

Still,
As I mentioned the air at sea level is 27
times denser than it is at the SR-71s "official" flight cealing of 85,000 ft.

PS
Don't go running for your periodic table to prove me wrong. Density is a function of electronic activity not atomic weight.

[GENIUS'02]

ok thats fair enough you know densities, great, i don't have the time or inclination to go around melting metals to see, what is already obvious, that it requires more energy to push through a denser medium. howerev i do not think people it this room are saying that it doesn't require less energy to move through air at a higher altitude where it is 1/27th as dense. what they are saying is that due to the decrease in pressure and density of the air, the increase in velocity is simply a balance for the reduced lift but it has a definite maximum which cannot be exceeded as its engines are unable to use the less dense air to gain what ever maximum their engines could achieve if the air resistance was 0 but the density of the air was the optimum level. just for the record, its impossible.

[Valiant Dancer]

On 2002-08-29 20:26, SAMU wrote:
Just thought I'd add what I call a hands on illustration of density variation. Make of it what you will. (I'm sure some of you kids will trash it as much as you can.)

Iron is 7 times denser than Water. Hold some Iron in one hand and some Water in the other. Heft them in your hands, feel how much more energy one requires to move than the other. Imagine a ship moving through Water, pushing aside the water in its path. Now imagine the ship pushing its way through... But iron is solid and you can't move through it. But you can move through Mercury. Mercury is 13.5 times denser than Water. But you probably aren't going to have the chance to have a good handfull of Mercury to play with. Get ahold of some Lead instead. It is only 11.3 times denser than Water but is a lot easier to get. If you have the means check out some Gold. Its density is 18.8 times that of Water. Although you wouldn't want to touch it you can compare it to Uranium at 18.9 times denser than Water. You might be able to get a hand on some Tungsten at 19.3. Over that almost everything else in my list is radioactive. Plutonium, 19.8 ?Neptunium?...20.4. Platinium 21.4. (If you could spare a hand full of that send it ot me, I'd like to test my theory on that one myself) And the densest element in my list which is Iridium at a whopping 22.4 times denser than Water.

Still,
As I mentioned the air at sea level is 27
times denser than it is at the SR-71s "official" flight cealing of 85,000 ft.

PS
Don't go running for your periodic table to prove me wrong. Density is a function of electronic activity not atomic weight.

SAMU, say it with me. The density of air also helps lift and engine efficiency. While resistance decreases, so does lift as there is less dense air to form the pressure difference. There is also less air to bring the engines to their maximum thrust at 85,000. You go into less dense air, and the engines total thrust output drops due to inadequate oxidizer. This thrust does not drop off in an Atlas rocket due to the consistant oxidizer pressure from the wholly internal system.

Have I made it clear enough to you?

[SAMU]

Valiant Dancer

Say it with NASA.
http://www1.msfc.nasa.gov/NEWSROOM/n...02/02-168.html
"The innovative air-breathing rocket engine for the operational vehicle would get its initial power boost from specially designed rockets in a duct that captures air, an arrangement that improves performance about 15 percent above conventional rockets. Once the vehicle has accelerated to more than twice the speed of sound, the rockets are turned off and the engine relies solely on oxygen in the atmosphere to burn its hydrogen fuel. When the vehicle has accelerated to more than 10 times the speed of sound, the engine converts to a conventional rocket-powered system to propel the craft into orbit.

As you can see NASA has already revealed that airbreathing "scramjets" are expected to go mach 10. Anyone who says mach 3 is a limit for airbreathing engines is not up to date with current NASA releases.

Of course this is not an SR-71 but technology of this nature that is revealed today was done secretly years ago.

[overrated]

Everybody say it together now:

The SR-71 does not have scramjets, nor does it run on liquid hydrogen fuel. So the existence of scramjet technology is a moot point for the purposes of our discussion. Might as well say: satellite phones exist, therefore my cell phone is a satellite phone.

[Firefox]

To elaborate on overrated's statement, if you read the article and understood it, you would understand that the scramjet would have been unable to function had it not been for the booster rocket propelling it to operational speed, which is, obviously, far faster than the SR-71's design limit. To top this, the SR-71 uses ramjets, which rely on slower airflows than scramjets.


-Adam

[Kaptain K]

OK, SAMU.

Let me see if I'm following your logic(?).

NASA is doing "bleeding edge" research on a (single stage to orbit) combination rocket-scramjet engine that (if all goes well) will begin ground testing four years from now.

Therefore:

The SR-71 (turbojet w/afterburner, no rockets) had this ability (single stage to orbit) forty years ago.

Have I got it right?

_________________
Be alert! The world needs more lerts.


<font size=-1>[ This Message was edited by: Kaptain K on 2002-08-31 22:24 ]</font>

[SAMU]

Firefox
You must have missed the part in the article where it says that "Once the vehicle has accelerated to more than twice the speed of sound, the rockets are turned off and the engine relies solely on oxygen in the atmosphere to burn its hydrogen fuel."

Well below the revealed speed of the SR-71. I posted that part, I don't see how you missed it.


GENIUS'02
This page:
http://www.hq.nasa.gov/office/pao/Hi...P-60/ch-5.html
Says
"The data also confirmed another peculiar trend of hypersonic flight: the reduced importance of the wings for lift."

I'm go