B707 Enginer Pylons
Not sure this is the correct forum to ask this, but I thought you'd be the guys to know.
Why is that some JT3 engine pylons are curved on top and go all the way to the front of the engine intake, whereas others are straight but don't come as far forward as the engine intake?
Invariably you see a mix of straight and curved pylons on the same aircraft. On some photos on airliners.net you see one outer engine with a straight pylon but the other outer engine with a curved pylon.
Also, some engines seem to have a series of vents around the circumference of the engine intake, whereas others don't. (I've noticed that early B747 JT9's had these vents as well, but not later ones).
Can anyone explain these differences please.
airsmiles