There I went with my pen. I showed my problem to the “pen doctor”–a clear lack of ink flow when flexing the nib, and problems to start—, and I let him work. He changed the feed and readjusted its inner core. He also tried to modify the geometry of the nib by pushing the tip downwards, like trying to make a posting nib—clearly an attempt to reduce the flexibility of this falcon nib.
The pen indeed improved. The flow is now more adequate to the demands of the flexible nib, and it now more reliable at starting. But the problems have not disappeared—the nib still railroads more often that what is desirable even if writing slowly. Better behaved pen it is now: acceptable for regular writing, but not up to the real challenge of its flexible character.
Writing "I am" the railroading became very evident, and was followed by a total absence of ink in the nib—the m is totally lost.
The “pen doctor’s” recommendation was the same I received at the Pilot headquarters at the Pen Station: don’t flex, write lightly. Flexing, he added, is the cause of the problems to start to write because it removes the ink from the nib.
As I already explained, there is no point in this nib other that its flexibility in order to write with some line variation. For any other purpose, Pilot makes a number of nibs perfectly able to perform correctly.
Falcon nibs by Pilot showing the characteristic cuts on the sides. The size 15 is less flexible, but more reliable. More expensive too.
If not to flex, why cutting the sides of the nib?
So, the conclusion is that Pilot has failed twice with this nib—in the design of the feed, and in the support to those who bought it. Blaming the customer is seldom a good strategy.