The Institute also operated a couple of wonderfully eccentric aircraft called the Hurel-Dubois HD34. I saw F-BICU operating out of Dublin Airport during 1972 (I think). They were twin radial piston engined devices with a really long span, high mounted large dihedral wing partially supported by struts (a la Cessna 172). They also had a fixed spatted pair of mainwheels but with a retractable nosewheel. To cap it all, the tailplane also sported a fin at each extremity, even though the plane had a conventional tall tail fin in the usual place.