Spitfire Mk14/18 rudder shape. By John of Aero club.

There is some confusion with the rudders fitted to the Mk.14 and 18 Spitfires. I find that the Morgan/Shacklady "bible" is often less than helpful and sometimes irritating. As Edgar mentioned in a previous post (on contra props) the 14/18 fin/rudders areas are given as the same. This is not so and this "red herring"is the cause of some confusion. The 14 fin went through a considerable change in area and the only real reference given in the"bible" is a sketch showing an interim straight leading edge modification and it omits to mention that the height at the rudder post was increased by almost 3". The standard rudder post height of all the earlier Spits was 58".

The extra 2.75" fin height increase was achieved by fitting a "block false tip". The Mk.18 had a broader chord rudder and a deeper horn balance. This rudder was also fitted to other Mk.14 based airframes,( by the simple expedient of "removing the block") such as FR14e, 19, and the Mk.21 when fitted with a contra prop.

This illustration I have cobbled up might help. It is the tail of an FR.14e and I have superimposed the outlines of the Mk.14 and Mk.18 rudders on to it, the white area is the "block" . The blue outline is the 14 and the red 18.

The join line (lower edge of the block) seldom shows up on photos and is often shown as a panel line in drawings but too low down, a mistake repeated on my own Mk.21 conversion as this was made originally to the Cook drawings.

John