Ardem engines are Volkswagen conversions built by Avions Roger Druine of Paris (16e), France. Roger Druine was well-known in Europe for his Druine Turbulent, Turbi and Condor light aircraft until his death in 1958. Ardem engines continued to be built until about 1977. Rollason Aircraft and Engines, Ltd. of Croyden, Surrey, United Kingdom began in about 1958 to build and market the Druine Turbulent light aircraft and Ardem engines that power them under license from Druine. Rollason was reported (J64-65) to have produced 32 Ardem conversions by February 1963 and continued operations until about 1984. These two companies were the first VW converters to be listed in Jane's All the World's Aircraft; Ardem in 1957-1958 and Rollason in 1958-1959. In all of the Jane's references, only the O-73 seems to have been converted by Ardem, despite the report in BGP that only the O-91 was produced by Ardem.
O-69 - - {2.953 / 2.520 / 69.0} / {75 / 64 / 1131}
Same stroke as O-73.
4cyl; Druine VW conversion; 25-28hp@N/Arpm; 1952-1960; Wt = N/A.
Carbureted engine with unknown ignition.
AW.
Applications: (France) Druine D.31 Turbulent.
O-73 - - {3.031 / 2.520 / 72.7} / {77 / 64 / 1192}
Same bore as O-78.
Same stroke as O-69.
4cyl; Ardem 4 CO2; 31hp@3000rpm; 1957-1977; Wt = 120-133#.
Carbureted, dual-ignition engine.
BGP; J57-58toJ76-77.
Applications: (France) Druine D.31 Turbulent.
4cyl; Rollason 4 CO2; 31hp@3000rpm; 1958-1971; Wt = N/A.
Carbureted, dual-ignition engine. The Rollason conversion differed from the Ardem only in having a Solex side-entry carburetor using preheated air.
BGP; J58-59toJ70-71.
Applications: (UK) Rollason-built Druine D.31 Turbulent.
4cyl; Rollason RTW; 31hp@3000rpm; 1958-1969; Wt = N/A.
Carbureted, dual-ignition engine; as Rollason 4 CO2 except for a direct-drive magneto shaft on the rear face instead of a chain-drive to a magneto mounted under the engine.
J58-59toJ68-69.
Applications: (UK) Rollason-built Druine D.31 Turbulent.
O-78 - - {3.031 / 2.717 / 78.4} / {77 / 69 / 1285}
Same bore as O-73.
Same stroke as O-91, O-97.
4cyl; Rollason 4 CO2 FH Mod "1300cc"; 40hp@N/Arpm; 1960-1969; Wt = N/A.
Carbureted, dual-ignition engine; as Rollason 4 CO2 except for an increased stroke.
J60-61toJ68-69.
Applications: (UK) Rollason-built Druine D.31 Turbulent.
O-91 - - {3.268 / 2.717 / 91.2} / {83 / 69 / 1493}
Same stroke as O-78, O-97.
4cyl; Rollason 4 CO2 FH Mod "1500cc" Mk. 4; 45hp@3300rpm to 63@3600; 1964-1984; Wt = N/A.
Carbureted, dual-ignition engine; as Rollason 4 CO2 Mod "1300cc" except for an increased bore. The higher performance version has a compression ratio of 8.5 to 1, while the lower has a ratio of 7.8 to 1.
J64-65toJ83-84.
Applications: (Australia) Corby Starlet Mk.II. (UK) Rollason-built Druine D.31 Turbulent; Taylor (John) J.T.1 Monoplane.
4cyl; Rollason 4 CO2 FH Mod "1500cc" Mk. 5; 55hp@N/Arpm; 1964-1984; Wt = N/A.
Carbureted, dual-ignition racing engine.
J64-65toJ83-84.
Applications: (UK) Rollason-built Druine D.31 Turbulent, Rollason Luton Beta B3.
4cyl; Rollason 4 CO2 FH Mod "1500cc" Mk. 10; 45hp@N/Arpm; 1968-1984; Wt = N/A.
Carbureted, dual-ignition version of Mk. 5 for the D.31A Turbulent, which combination qualified for a full Certificate of Airworthiness in the UK.
BGP; J70-71toJ83-84.
Applications: (UK) Nipper Aircraft Nipper III [G-AVKH]; Rollason-built Druine D.31A Turbulent prototype [G-ARLZ].
O-97 - - {3.366 / 2.717 / 96.7} / {85.5 / 69 / 1585}
Same stroke as O-78, O-91.
4cyl; Rollason 4 CO2 FH Mod "1600cc" Mk. 11; 55hp@3300rpm; 1969-1984; Wt =158-168#.
Carbureted, dual-ignition (except single-ignition for motorgliders) engine; as "1500cc", but with increased bore.
BGP; J69-70toJ83-84.
Applications: (Australia) Corby Starlet Mk.I. (UK) Nipper Kits and Components (formerly Nipper Aircraft and originally Avions Fairey of Belgium) Nipper IIIa, Nipper IIIb [G-AXLI]; Slingsby T.61F Venture motorglider (a license built German Scheibe SF-25B Motor-Falke), RAF version called the Venture T.Mk 2.