Contrail formation is all to do with temperature and humidity, we all know that the higher you go the colder it gets but the humidity levels do not change in a similar linear fashion and can be in bands of higher and lower percentages as an aircraft climbs or decends (ask a GA pilot about carburettor icing)

Not only is it a question of the surrounding atmosphere, as this a weather phenomenon the height at which contrails form varies from day to day,
but also the temperature and humidity of what the engine is blowing out.
(this is also altered to some small degree by what it sucks in)

There is a good explanation of the theory on this link plus to proove the point about engine breath a remarkable photograph of an Airbus and a 707 flying side by side, one making contrails the other not !

http://www.af.mil/environment/contrails_contrail.asp

It’s up on the BBC news website
http://news.bbc.co.uk/#

Oh what fun…………….NOT !

The museums website quotes it as a “veterans flypast”, had some helos as well in the morning apparently.

Oh yes, loads of oooohh’s and aaaahh’s and wow’s from folk looking through the 125 but, light pollution has knocked it on the head. I know I can get “further out” but local conditions now prevent it happening.
If you live somewhere that is properly dark at night they are great bit if kit, get yourself onto e-bay. 🙂
Paul, those images are superb and shows what can be done, all be it with a whopper :rolleyes: but even they are not too dear these days.

A likewise post DX lift to this one, come on Taffy… spill the beans 🙂

In the US the majority of departmental staffs change along the winning party lines as well.
In the UK this would be the equivalent of the top third of the Civil Service changing from theoretical impartiality, to the political colour of the winning party when there was a change of ruling party.

In the UK the House of Lord’s thoeretically restrains the House’s of Parliament i.e. the Govenment and the Civil Service “guide” the Ministers of State with regard as to what can (or cannot) be done, giving a sort of impartial advice service based on decades of experience for want of a better phrase.

Like or loathe the British civil service for maintaining the establishment status quo, at least they are experienced in what can and can’t be done, how to ‘play the game’…. as it where.

In the US that experience base changes with every President so it’s not so much a Sir Humphrey’s sighing and condescending “yes minister” to a “YES SIR MR SENATOR !”

Joining your local club is sound advice,

For all things ETX try here

http://www.weasner.com/etx/menu.html