Photo courtesy of Jürgen Gassebner, http://www.elster-porschemuseum.de

See Engine History discussion  http://www.enginehistory.org/phpbb/viewtopic.php?t=565

http://dedeporsche.com/2011/06/04/porsche-356-of-the-air-a-lavishly-restored-putzer-elster-b-german-aircraft/