Another piece of blatant ignorance by SL0WMAN (2023 Update)

I take that to mean that "faster in thinner air creates the same drag as slower in denser air."

Of course it does. But drag - like lift - depends not only on speed but also on the density of the air in the immediate vicinity of the wing. At higher altitude the density of the air is lower, so you have to fly faster to generate the same lift, but you also generate the same drag - not more - even though you are flying faster.

That was the message I was trying to convey, and Flyguy seems to have entirely missed. Possibly deliberately, but his next paragraph is equally defective.

What Flyguy hasn't noticed is that the SR-71 was supersonic, which meant that it created shock waves over the whole air-craft - not just the fuselage - and was operating in a very different aerodynamic regime from the aircraft we were talking about.

He linked to a discussion of parasitic drag, which is all about sub-sonic flows.

As is usual when Flyguy tries to pose an an expert, he's just exposed the shallowness of his thinking. Or blatant ignorance, as he would put it.

Flyguy wrote: ==========

----------------------------------------------------------------- There's an advantage in flying at higher altitude. You do have to fly faster to generate enough lift to keep you up there, but you don't generate any more drag, so you get where you want to go with less expenditure of energy. Variable pitch propellers help you do this."

--------------------------------------------------------------

** Not what was said.

** Not when thinner air compensates. ** ROTFLMO !!

How many " variable pitch " props did that thing have ?

..... Phil

** Just for some context, the density air at 60,000 feet is only 10% of that at sea level.

FYI that is the cruising altitude of the Concorde.

The SR 71 likes 85,000 feet better.

..... Phil

Flyguy snipped-for-privacy@yahoo.com wrote in news:074e86c1-fb6d-40c5-b526- snipped-for-privacy@googlegroups.com:

No, idiot. That is not what he said.

He specifically mentioned that the air is thinner and that THAT element meant less drag and therefore the ability to go faster for less cost. So it isn't "more drag" it is the same drag laws and at higher altitude with less molecules per cubic yard of air, there is less drag for any given speed. So 500 knots at sea level impinges more on the plane than 500 knots at 50,000 feet.

Don't see any supersonic jets going supersonic down at sea level.

Phil Allison snipped-for-privacy@gmail.com wrote in news:d7a84419-9dbb-4968- snipped-for-privacy@googlegroups.com:

It had a varible inlet and superstructure venturi shape.

Depending on the speed it acted as a ramjet.

"that thing"?

That thing between your ears needs a bullet. Do us a favor and give it one.

Phil Allison snipped-for-privacy@gmail.com wrote in news:be0a2933-23b3-49d6- snipped-for-privacy@googlegroups.com:

FYI, that was just the published figure.

DecadentLinux is Incredibly Funny: :

=============================

** But no props at all. ** Yep, it was a " thing ".

Just like you are a " raving idiot".

..... Phil

DecadentLinux...= Stand Up Comedian ======================================

** So what's the *REAL* one then ???

Maybe 850,000 ? 8.5 million ?

Make my day....

You do sometimes with military jets. I've been on a boat that was overflown by a couple of low-altitude supersonic jets. It was VERY noisy.

I can also remember the supersonic test flights over the UK during Concorde development. These were at relatively low altitude.

John

John Walliker wrote: ================

** The Fairy Delta 2 ?

IIRC, along a beach area in the south on England in about 1956 ?

Just before the Russians launched Sputnik.

.... Phil

Phil Allison snipped-for-privacy@gmail.com wrote in news:e4e1df96-e996-4239- snipped-for-privacy@googlegroups.com:

Yeah... Like I said... A RAMJET.

No props to you. You do not deserve any, putz.

DecadentLinux...is Hysterical -------------------------------------------------------

** ROTFL !!

This fool has missed his natural occupation - as a barber. Cos he can trim and change context like nobody else.

Maybe he can tell side splitting, wildly racist jokes at the same time ?

...... Phil

It's been done fairly recently:

The limiting case is orbit. Satellites can fly for centuries on very little fuel.

That's in the Flyguy class - satellites are in orbit, and traveling a lot faster than subsonic airliners, or any kind of electrically powered aircraft.

An satellite with an ion drive is a special case, but it is clearly not an aircraft.

It's a function aircraft design. Aircraft designed for high altitude flight will generally have lots of wing area to reduce the requirement for excess velocity needed for lift a high altitude. Most of the modern airlines seem to be optimized for 500 knots at 35,000 feet. Wing areas are humongous.

SR-71 was mainly trying to evade intercept by hostile SAMs, so the ultra-high altitude, for its day, was a primary requirement.

Hey SL0WMAN, the drag of the SR-71 is the result of the plane pushing molecules of air aside as it pushes through it. Supersonic flight creates shockwaves, but does not eliminate drag. The SR-71 had PLENTY of drag when it flew subsonically.

Fred Bloggs wrote: ===============

** Nonsense.

Lift is a mostly function of a wing's "angle of attack" and aerofoil shape. Passenger jets have small wing areas, with lots of movable devices fitted on the leading and trailing edges to increase lift at low speeds for take offs and landings.

..... Phil