Short Empire variant
Short Empire S.33
The Empire's final series: a modified S.30 with the new Pegasus XI engine, a development of the powerplant used by the original S.23. Of the three ordered only two were completed, Clifton and Cleopatra, delivered to BOAC; the third was scrapped when 75 per cent complete.
- 2
- Units built
- 24
- Passengers
History
The last order
In 1939 Imperial Airways ordered a modified S.30 that received the S.33 designation. The series kept the same construction as its predecessors but adopted the new Pegasus XI engine, a development of the powerplant used by the original S.23 series.
Of the three final aircraft only two were completed, named Clifton and Cleopatra, and delivered to the newly renamed British Overseas Airways Corporation. The third example was scrapped when 75 per cent complete.
Closing the family
The S.33 closes the Empire census: 42 «C Class» flying boats built, of which 31 S.23s, nine S.30s and two S.33s. The type's natural successor was not another sub-mark but the S.26, designated G-class by BOAC, an entirely new aircraft albeit of similar configuration: roughly 15 per cent larger, with far more powerful Bristol Hercules engines and an improved hull, intended for the North Atlantic route. The three that were built were immediately impressed into military service during the Second World War.
Census criterion
Neither the S.26 G-class nor the Short Mayo Composite's S.21 Maia is recorded as an Empire variant. The S.26 is, in the material's own words, «an entirely new aircraft»: a DERIVED TYPE with a sheet of its own. The S.21 was the carrier aircraft of the Mayo composite, built as a single example on the S.23 basis but with additional superstructure to carry the S.20 Mercury floatplane: also a derived type. The same rule separates the Short Sunderland from the Empire, despite their parallel development.