Plane geek stuff

W Balboos GHB

The narrator got it a bit wrong about why it's easier to go faster in space. Sure, gravity, as he claims, would be an obstacle IF one were opposing it, but the real hero (or lack thereof) is that there's no atmosphere to (1) slow the vehicle down, and (2) heat the vehicle up. It would go even slower under water . . .

Ravings en masse^

"The difference between genius and stupidity is that genius has its limits." - Albert Einstein

"If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010

CodeWraith

No, that's a X-15 covered with ablative heat protection, most probably before the flight.

Munchies_Matt

18,000 mph if memory serves me correctly. Puts a bit of wind into perspective eh? :)

Munchies_Matt

air+velocity=wind HOw fast is a rocket going? :)

Munchies_Matt

air doesnt have any resistance until it has velocity relative to the object whereupon it is wind. ;P

CodeWraith

For example, I also never saw this[^] before, if we are already looking at the X-15.

Daniel Pfeffer

Escape velocity at the Earth's surface is about 11.2 km/sec, which is 40,320 km/hr, which is 25,200 mph.

If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill

F ES Sitecore

Munchies_Matt wrote:

air+velocity=wind

It's wind if it's the *air* that has velocity, not an object moving through it.

R Giskard Reventlov

Gravitational Escape Velocity with Saturn V Rocket by Ron Kurtus - Physics Lessons: School for Champions[^]

Munchies_Matt

I see, this is your deffinition of wind is it? What do you call a windscreen then? :laugh:

F ES Sitecore

If you get your scientific knowledge from badly-named items then it's just as well you don't work at NASA. What kind of food stuff is a peanut? A strawberry? What's your pencil lead made from? What's tin foil made from? What kind of animal is a koala bear? What kind of animal is a horned toad? Where was Chinese checkers invented?

jeron1

Just goes to show how far ahead of its time the SR-71 was.

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

Munchies_Matt

Wind Resistance | Definition of Wind Resistance by Merriam-Webster[^] " Definition of wind resistance : the resistance that still air offers to movement especially of a vehicle" :laugh:

F ES Sitecore

Now you're getting your scientific info from Merriam Webster? Not much better.

Daniel Pfeffer

I agree that the actual delta-v produced by any practical rocket that reaches escape velocity must be higher than 11.2 km/sec. This is because (a) the acceleration profile is not a step function, and (b) using the highest acceleration that the astronauts were capable of enduring would result in the spacecraft overheating because of air resistance (those pesky Engineering considerations... :) ). This, however, that does not change the fact that the escape velocity at the Earth's surface is approximately 11.2 km/sec. This gives the absolute lower bound on the delta-v that must be given to an object that is to escape the Earth's gravity.

If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill

Munchies_Matt

Whereas you get yours from your 'opinion bank'. :laugh: Unlike many people (everyone?) here I studied physics in depth, since my principal formation was in mech/aero engineering. The mistake you make is assuming the earth has some relevance in this. When the object experiencing the wind is not moving relative to the earth you call it 'wind'. When it is you call it 'air'. Earth centric views in science died with the church, you do remember the heresy of Galileo dont you? The correct way to view this is the body and air have different velocities. This creates wind. Period.

F ES Sitecore

Munchies_Matt wrote:

I studied physics in depth, since my principal formation was in mech/aero engineering.

I find that hard to believe when you cite a dictionary as proof.

R Giskard Reventlov

And plenty of cogent reasons why it would be better to build and launch ships from orbit or a body with a lower escape velocity requirement (putting to one side the practicalities of setting that all up in the first place - nice to dream).

Munchies_Matt

I find your inability to accept that a dictionary and physics have the same deffinition hard to believe. How about engineering? Here are some pics of wind resistance:wind resistance - Google Search[^]

Joan M

Tell that to some underpants out in the wild... :laugh: