Crossflow engines are converted from Subaru automobile engines and are built and marketed by Crossflow Aero Corp. of Shelburne (formerly of Palgrove), Ontario, Canada. Crossflow was founded in 1996 in its present form in Canada, but has its roots in the work of J.J. and Jorge Alonso (now President & CEO of Crossflow) of Uruguay, who were modifying BMW engines for auto racing in the early 1970s. All Crossflow Subaru conversions require reduction of propeller rpm from that of engine rpm; i.e., Propeller Speed Reduction Units (PSRU's). The Crossflow PSRU incorporates planetary spur gears and is of the firm's own design, although early engines were reported (SA7/97) to have had Ross gearboxes. Crossflow advertised (SA2/97) that after three years of research and development, the first engines were flying in 1996. Crossflow advertised and was mentioned briefly in Sport Aviation (SA) several times in 1997-1998, but did not resume advertising for a few years (SA1/04, KP3/04). Most of the information here has been compiled from the Crossflow Website as well as "Kitplanes" (KP) and "Sport Aviation" (SA) magazines. The applications below are available as firewall-forward kits for the various Van's and Zenith aircraft. The initial designation of engines in 1997-1998; e.g., CF4-33, had the following meaning. CF was for Crossflow, 4 was for the total number of camshafts (double overhead camshafts for each cylinder bank), and 33 for the approximate displacement in deciliters. Current designations are similar except that the former CF4-33 is now the CF6-33, where the 6 now denotes the number of cylinders, instead of the number of camshafts. The meaning of the post-designation letters; "none", "T", "THO", and "THOG2" are not described clearly on the Crossflow Website. It would seem that "none" indicates a normally-aspirated engine, "T" a turbocharged engine, while the "THO" and "THOG2" are turbocharged, higher-output engines. They mention that the maximum output of any of the engines is, apparently, the "THOG2" version (where present) and that the "THO", "T", and "none" are successively derated from that maximum performance. Note that the operating rpm increases as well as the output with the tuning changes. All of these engines are non-certificated engines for use in experimental, homebuilt aircraft.
OL-122 - - {3.622 / 2.953 / 121.7} / {92 / 75 / 1994}
Same stroke as OL-135, OL-205.
4cyl; CF4-20; 180hp@5800rpm; 1996-present; Wt = 360#.
Liquid-cooled, multi-point fuel-injected engine with electronically-controlled single ignition (a coil at each cylinder) and dual overhead camshafts (DOHC) on each cylinder bank; geared to 0.427 by Crossflow gearbox.
SA2/97, 4/97, 7/97, 4/98.
Applications: (Canada) ARV Griffin. (US) Quikkit Glass Goose; Van's Aircraft RV-4, RV-6/-6A; Zenith STOL CH-801 prototype.
4cyl; CF4-20T; 200hp@6000rpm; 1998-present; Wt = 360#.
As CF4-20, but with turbocharging.
SA4/98.
Applications: (Canada) Murphy Rebel. (US) KLS Composites SQ-2000; New Glasair GlaStar; Lancair 360; Van's Aircraft RV-7/-7A, RV-8/-8A; Zenith CH 801.
4cyl; CF4-20THO; 250hp@6250rpm; 1998-present; Wt = 360#.
As CF4-20T, but with additional tuning and operating at higher rpm.
SA4/98.
Applications: None found.
OL-135 - - {3.815 / 2.953 / 135.0} / {96.9 / 75 / 2212}
Same stroke as OL-122, OL-205.
4cyl; CF2-22; 170hp@N/A rpm; 1996-1998; Wt = N/A.
Liquid-cooled, fuel-injected engine with electronically-controlled single ignition (a coil at each cylinder) and a single overhead camshaft (SOHC) on each cylinder bank; geared to N/A by Crossflow gearbox.
SA2/97, 4/97, 7/97, 4/98.
Applications: (Canada) Murphy Rebel.
OL-205 - - {3.819 / 2.953 / 202.9} / {97 / 75 / 3325}
Same stroke as OL-122, OL-135.
6cyl; CF6-33, formerly CF4-33; 250hp@5650rpm; 1996-present; Wt= 460#.
Liquid-cooled, multi-point fuel-injected engine with electronically-controlled single ignition (a coil at each cylinder) and DOHC; geared to 0.427 by Crossflow gearbox.
SA2/97, 4/97, 7/97, 4/98.
Applications: (US) Aerocomp 6, Monster.
6cyl; CF6-33T, formerly CF4-33T; 300hp@5600rpm; 1998-present; Wt= 460#.
As CF6-33, but with turbocharging.
SA4/98.
Applications: (US) Van's Aircraft RV-10/-10A.
6cyl; CF6-33THO, formerly CF4-33THO; 320hp@6050rpm; 1998-present; Wt= 460#.
As CF6-33T, but with additional tuning and operating at higher rpm.
SA4/98.
Applications: (US) Prescott Pusher; Velocity XL.
6cyl; CF6-33THOG2; 350hp@6250rpm; 2003-present; Wt= 460#.
As CF6-33THO, but with a further level of tuning and operating at higher rpm.
Crossflow Website.
Applications: None found.