Air France jet missing off Brazil coast

If you have a 100kts tailwind and a 100kt airspeed then (without taking into account altitude) then your groundspeed will be 200kts.

If you have a 100kts headwind and a 100kt airspeed then then your groundspeed will be 0kts!!! But you will still be flying at an airspeed of 100kts.

I hope this helps.

it hit me before you posted. If stall speed is expressed as air speed not ground speed, then wind makes no difference as the airspeed is always relative to windspeed.

No, it is not. It depends upon weight of aircraft, configuration (flaps etc etc) and whether the aircraft is turning.

I think you have got it now Owain. Also another way of helping to explain is for you to swim upstream at 5mph in the Isar which is flowing at 5mph, then turn round and swim downstream...the water current is the same as the windspeed.

I appreciate the concept of "Nope, can't be done". Will I ever be able to have a cup of tea sitting on the sun? No. That is a big proper 100% No.

Could you make a passenger plane with ejector seats? Yes, you sure as fuckety fuck could. No ifs, not buts, no questions - you absolutely COULD with current technology we have to hand.

We can get our knickers all knotted about the costs, the possible discomfort etc, but FIRST it must be acknowledged that it could be done.

This guy left the plane real quick. One minute he was there next thing he got sucked out through a hole in the floor – seat and all.
http://books.google.com/books?id=twKfXowAi...lt&resnum=1

Someone told me that the worst accident one can have when flying is when sitting on the toilet the plane has a major cabin decompression. Not very nice.

For the sake of answering you, yes it could be done.
But jumpinmg out of a plane in shorts and flip flops at 35,000ft might actually make your blood boil due to the lack of air pressure, suffocate you and then what's left would freeze. Mmmm, but yes it is possible.

... on a treadmill.

And your eardrums would probably burst with the sudden air pressure difference, and filling a plane with explosives would be the terrorist's dream...

Which is what I meant to say, but somehow couldn't manage to say

Sorry, of course - I simply meant that stall speed is a constant assuming those variables are. Obviously weight and I guess most importantly config/turn are important factors.

Next test - am I right in thinking that the swept back wing design (I believe first seen in the Me262) is that way to allow supersonic or near supersonic flight, as straight wings develop a compression on the leading edge? I've always thought that, but an officer in the RAF (not a pilot) denies it.

So...

You know how they tow gliders up into the air using a real plane at the front?

I reckon they should make planes in 10 sections, like a train, connecting each "carriage" with a nice strong cable. Engine at the front, baggage at the rear etc.

Each carriage has its own integrated parachute section.

If the engine blows up, or 1 section blows up, you can detach your "carriage" and float back to earth.

Get my patent attorney on the phone NOW.

Edit: I could see landing being perhaps a little "tricky".

i thought it was to reduce drag at near super-sonic speeds.

Jimbo you are correct. The swept wing (employed on RAF Tornado) is to reduce the overall drag and allow it to fly at faster speeds (the compression that you talk about is the induced drag. There are several types of drag BTW)

The primary advantage of the delta wing design is that the wing's leading edge remains behind the shock wave generated by the nose of the aircraft when flying at supersonic speeds, which is an improvement on traditional wing designs. While this is also true of highly swept wings, the delta's planform carries across the entire aircraft, allowing it to be built much more strongly than a swept wing, where the spar meets the fuselage far in front of the center of gravity. Generally a delta will be stronger than a similar swept wing, as well as having much more internal volume for fuel and other storage.

Not from WIKI - honest!

Swept wing (Wikipedia)

A swept-wing is a wing planform common on jet aircraft capable of near-sonic or supersonic speeds. The wings are swept back instead of being set at right angles to the fuselage which is common on propeller-driven aircraft and low-speed jet aircraft. This is a useful drag-reducing measure for aircraft flying just below the speed of sound, though straight wings are still favored for slower cruise and landing speeds and aircraft with long range or endurance. Swept-wings provide lateral stability and it was for this reason that the concept was first employed in the designs of J.W.Dunne in the first decade of the 20th century, e.g. the Dunne D.1.

Unusual variants of this design feature is forward sweep, variable sweep wings, and pivoting wings. Swept wings as a means of reducing wave drag were first used on jet fighter aircraft. Today, they have become almost universal on all but the slowest jets (such as the A-10), and most faster airliners and business jets.

Didn't they use this method to get the troops into Europe in that "Bridge too far" thingy?

According to the wiki, which i just read, this wasn't actually the first reason for introducing them, though. It was for increased lateral stability.

Hmmmmmmmmmmm.

Or then rather than a cable we have like, snap-off sections between each pod? So be a long stretched out plane?

Bit like this: