The Brits used several different fitting combinations in fluid (hydraulic/fuel/air pressure/vacuum/etc) systems. As I was told at the beginning of my training -
there are three ways to build an aircraft - the right way, the wrong way, and the British way.
Starting with flared systems - they only had one flare angle - I don't know what the angle is because you only need the one tool kit for British flares instead of two for US aircraft - or one after about 1940. That said the Brits make up for it in multiple ways of using the flare and creating assemblies that make you hate working on British aircraft.
This is a typical flare fitting and a cutaway diagram of how it assembles. My apologies for the sh*t photos that follow.
This is a different way to use parts 1 & 2 above (now ID'd as 3 & 4) with some other parts to produce a similar joint
Now parts 1 & 2 become 2 & 3 and there is an adaptor so that the flared tube can connect to a fitting which requires a spherical end.
Confused yet - well lets throw in a different version of item 4 above - which conveniently shows the spherical fitting diameter as S
Well now - from that the Brit angle is 32
+ 1/2 degrees - that's good I learned something today.
That spherical end is not to be confused with the 60 degree cone used on some other fittings
Which are used with silver soldered end fittings like this - again **** photo
And naturally there are fittings and combinations that have a foot in each camp like these - note that the olive in this one is a different shape and part number to the similar one above.
Did I mention
the right way, the wrong way, and the British way? Or that I hate working on British aircraft? Or that on top of AGS specs there are BS specs from Bristol and that other companies had their own specs? The latter is not only a British trait though - Curtiss and Lockheed had a bad case of that mental illness as well
.
And then there are the flareless fittings like these used in low pressure systems - the black ring is made of a rubber compound
Among other connections the Brits used this is one from the Anson brake system.
Did I mention
the right way, the wrong way, and the British way? Or that I really hate working on British aircraft?