A German sword for Spain

**Spinners** · February 19, 2022

CASA 4100 'Espada' - Escuadron 23, Ejército del Aire, 1946

Despite being one of the fastest fighter aircraft in the world at the time of its development the promising Heinkel He 100 was not ordered into series production due to the German Ministry of Aviation's policy that allocated fighter development to Messerschmitt and bomber development to Heinkel with the additional reason that the production problems with the Daimler-Benz DB 601 12-cylinder liquid-cooled piston engine were so acute that all other designs based on the DB 601 engine were cancelled or suspended. Whilst Heinkel did consider switching to the Junkers Jumo 211 that engine was also in short supply and the He 100 could not easily be adapted to accept the Jumo 211 except via an extensive redesign but still with inferior performance.

This was frustrating for Heinkel as they knew that the He 100 was a fine fighter aircraft that had already attracted interest from other countries. Indeed, Japanese and Soviet delegations had visited the Marienehe factory in October 1939 followed by a Spanish delegation in December 1939. All three were impressed by the design but whilst Heinkel was allowed to look for foreign licensees for the He 100 the engine supply problem still persisted. Even though Spain had a considerable air force the aircraft operated by the Ejército del Aire were mainly survivors from the Spanish Civil War with most aircraft being either worn out or obsolete. Despite this, Spain's declared neutrality and desperate economic situation meant that they could wait a while longer and properly organise obtaining licences and establish a production line for both the He 100 airframe and the DB 601 engine.

CASA were a natural choice to manufacture the He 100 as they had already obtained aircraft licenses from Germany for the Bücker Bü 133 Jungmeister, Gotha Go 145, Ju-52 and He-111. Franco authorised an extension of the CASA factory in Tablada in Seville specifically for the construction of the He 100 which was soon given the in-house designation of CASA 4100 and officially named 'Espada' (Sword). Acquiring the DB 601 engine proved to be slightly more difficult but eventually Franco negotiated with Mussolini to source it's DB 601 engine from Italy as Alfa Romeo had already gained a production licence from Daimler-Benz for the DB 601 engine (as the R.A.1000 R.C.41-I Monsone) and were already tooling up for production with engines destined for the Macchi C.202 Folgore and Reggiane Re.2001 Falco II fighters.

Construction of the Tablada factory extension and the CASA 4100 production line took up the majority of 1940 and 1941 but CASA eventually delivered it's first CASA 4100 aircraft to the Ejército del Aire in March 1942 with the aircraft entering service with Escuadron 23 in the early summer. Production was a long drawn out affair with the last of 227 aircraft coming off the production line in May 1951 and the CASA 4100 remained in service until late 1964.