Even among great names like the Duofold and Jotter, the Parker 51 stands out as the most significant Parker pen in their history. It may even be the most significant pen in history. And now, it's back, in a revised and updated form, to better fit with modern practicalities. Cartridge or converter filled, but still featuring that hooded nib and sleek lines.
So what made the original '51' so significant? The whole ink feed system was special and new. The hooded nib only just emerged from the pen's grip section right at the tip, which meant ink could be wrapped around it. The nib itself was actually a little tubular shape, with the ink feed running through the middle, and a 'collector' wrapped around the outside. If you've ever looked at a modern rollerball with a transparent grip, and seen those fins inside, with ink between them, that's what the collector is like - like the Pilot V-System range. A series of closely-spaced fins that can gather ink, holding it wrapped around the nib. This keeps the nib wet, with a ready supply of ink.
It was originally done to enable the use of a super fast-drying ink, but that turned out to have other problems, damaging the pens, so it was quickly dropped. But the result is a pen that's ready to go any time, much less likely to dry out.
While the same design of collector isn't often used in modern pens, it's very normal now for pens to have a lot of fins connected to the feed, holding ink close to the tip and ready for use, even in rollerball pens. The collector lives on, influencing the design of many pens all over the world.
Then there was the filling system, though that hasn't continued to modern versions. After some early versions using the Vacumatic system, Parker introduced the Aerometric filling system. It looked much like a simple rubber sac with a press-bar to squash it down for filling, but inside was a little more complicated. A tube running up the inside of the sac meant the pen could fill much further, using repeated squeezes of the sac, to hold a lot more ink. And a carefully positioned hole along that tube allowed air pressure to equalise, making the pen much safer to use on aeroplane flights, with far less risk of leaking.
