I succumbed to desire and spent money that might better not have been spent. I was encouraged by the observation that my 1940s Parker Vacumatic, now that its ink-fill mechanism has been repaired, really is an excellent pen; and the 51 is an even more advanced example of Parker pen-gineering.
It’s an aerometric fill Parker 51 from the early 1950s, but the barrel and hood actually are substitutes made from ebonite by Bexley within the last few years. I’ve seen pictures of these Bexley 51s and they can be quite colorful, but I was attracted to the speckled appearance of this one. I’m not a big fan of 1950s car colors (or of 1950s cars, in general, yuck!), but for me such colors can be acceptable in a pen.
The hooded design was a specialization for the use of a quickly drying ink (branded ‘Quink’), to keep the ink immediately available to the nib but without drying out. There is actually a fairly complex system of non-moving parts hidden behind that hood. I think I have seen a similar system in some see-through disposable roller ball pens.
(Aerometric fill is basically just a squeeze bulb. There is a PVC sack with a spring mounted over it, and you push on the spring and release to load ink into the sac. I have some cartridge-to-bottled-ink converters for Shaeffer pens that have the same mechanism. Vacumatic fill, which was used in early 51s and of course in the pens branded ‘Vacumatic’, is a sort of air pump for evacuating the interior of the pen barrel, I believe, and is considerably more complicated; there is no sac but there is an elastic diaphragm. In most modern bottled-ink pens and most converters, the mechanism is like that of a syringe, and is called piston fill.)