Franklin, Aircooled Motors, Doman-Marks (US);
Franklin Aircraft Engines, WSK-PZL (Poland)

Part 2: O-315 through O-805


This is the second part of the Franklin engine compilation. It includes the engines with larger displacement, namely from the O-315 (6AL-315) through the O-805 (12AC-806). All families of Franklin horizontally-opposed aircraft engines are listed in the Table of Franklin Engine Families. This Table gives a compact reference to their chronological and technical development. The Franklin introductory material is contained in the first part of the Franklin compilation and includes a Table of Equivalence between Franklin designations and this Website's designations. The Franklin engines of smaller displacement from the O-110 (2A-110) through the O-300 (6AC-298) are given in the first part, as well, and can be reached here.

O-315 -- {4.375 / 3.5 / 315.7} / {111.1 / 88.9 / 5173}

This is my best guess as to bore and stroke.
Same stroke as O-110, O-120, O-175, O-200, O-225, O-235, O-265, O-300, O-335, O-350, O-400, O-595.
Franklin also called these engines the 6A3 series.

6cyl; 6AL-315; 175hp@N/Arpm; 1944-1945; Wt = N/A; TC = 234 in c.1944 - expired 12/5/50.
FAA Records (no longer available online).
Applications: None found.

6cyl; 6ALG-315; 175hp@N/Arpm; 1944-1945; Wt = N/A; TC = none.
Geared to N/A.
aerofiles.com (for application); J45-46 (for RC-1); PMB.
Applications: (US) Republic RC-1 Thunderbolt Amphibian (Seabee prototype) [NX41816].

O-335 -- {4.5 / 3.5 / 334.0} / {114.3 / 88.9 / 5473}

Same bore and stroke as O-110, O-225.
Same stroke as O-120, O-175, O-200, O-235, O-265, O-300, O-315, O-350, O-400, O-595.
6A4 series are the six-cylinder versions of the 2A4 (O-110), 4A4 (O-225) series; Franklin later called these the 6A-335 and 6V-335 series for their displacement. These engines were built in many versions and were the principal Franklin production engines in the 1950s, mostly for helicopters. Sorting out the different versions has proved difficult and is offered here as a beginning.

6cyl; 6A4-125; 125hp@2200rpm; 1945-1949; Wt = N/A; TC = none.
W46toW49.
Applications: (US) Goodyear GA-1 Duck [NX38280].

6cyl; 6A4-130; 130hp@2200rpm; 1945-1949; Wt = N/A; TC = none.
aerofiles.com (for applications); J47toJ49-50; S; W46toW49.
Applications: (US) Bunyard BAX-3 Sportsman [NX33170]; Southern Aerocar [NX59711].

6cyl; 6A4-135; 135hp@2450rpm; 1945-1949; Wt = N/A; TC = none.
W46toW49.
Applications: None found.

6cyl; 6A4-140; 140hp@2375rpm; 1945-1949; Wt = N/A; TC = none.
J47toJ49-50; S; W46toW49.
Applications: None found.

6cyl; 6A4-145; 145hp@2600rpm; 1945-1949; Wt = N/A; TC = 238 on 9/5/45 - expired 12/5/50.
aerofiles.com (for applications); W46toW49.
Applications: (US) Goodyear GA-2 Duck.

6cyl; 6A4-150; 150hp@2600rpm; 1945-1975; Wt = 277#; TC = 238 on 9/5/45.
This version was out of production by about 1960, but was reintroduced in about 1968.
aerofiles.com (for applications); AY51,52,60; J8; J47toJ75-76; S; W46toW59-60.
Applications: (US) Bartlett (formerly Babcock) LC-13A [NX18165]; Bellanca 14-13, 14-13-2, 14-13-3 Cruisairs; Goodyear GA-2 Duck; Stinson 108, 108-1 Voyagers; Taylorcraft 15A; Wittman Big X [NX31637].

6cyl; 6V4-178; 178hp@3000rpm; 1946-1960; Wt = 274-293#; TC = 244 on 3/19/46.
Vertically mounted helicopter engine; Military O-335-1, -3, -5. The 1948 Tucker automobile engine was developed from this, or the following 6V4-200 helicopter engine.
aerofiles.com (for applications); AMC; AY51,52; J47toJ59-60; W51toW59-60.
Applications: (US) Bell 47, H-13 Sioux; Hiller 360, H-23 Raven; McCulloch YH-30, HUM-1; Sikorsky S-52 helicopters.

6cyl; 6V4-200; 200hp@3100rpm; 1946-1970; Wt = 298#; TC = 244 on 11/26/46.
Vertically mounted helicopter engine; Military O-335-2, -4, -6. The 1948 Tucker automobile engine was developed from this, or the preceding 6V4-178 helicopter engine.
aerofiles.com (for applications); AMC; AY51,52,60; J47toJ69-70; W52toW57.
Applications: (US) Bell 47, H-13B, D, E, G Sioux, HTL-1; Hiller UH-12B, H-23A, B Raven, HTE-1, -2 helicopters.

6cyl; 6A4-165; 165hp@2800rpm; 1947-1975; Wt = 280-291#; TC = 238 on 6/18/47.
This version was out of production by about 1960, but was reintroduced in about 1968.
aerofiles.com (for applications); AY51,52,60; H&H (for Aeronca application); J8, J9; J47toJ75-76; W49toW59-60.
Applications: (US) Aero-Flight Streak-165; Aeronca 15AC Sedan; Goodyear GA-2B Duck; McKinnie 165 [N9Y]; Seibel S-4B helicopter; Stinson 108-2, -3 Voyagers; Temco TE-1B, YT-35 Buckaroo.

6cyl; 6AG4-185; 185hp@3100rpm; 1947-1950; Wt = N/A; TC = 238 on 6/18/47 - expired 12/5/50.
Geared to 0.632.
AY51,52; J47toJ49-50; W49toW53.
Applications: None found.

6cyl; 6V4-165; 165hp@N/Arpm; 1947-1950; Wt = N/A; TC = 244 on 12/22/47 - expired 12/5/50.
Vertically-mounted, fan-cooled helicopter engine.
W51toW54.
Applications: None found.

6cyl; 6A4-200; 200hp@3100rpm; 1952-1953; Wt = 288#; TC = 238 on 2/4/52.
Approved for horizontal mounting in helicopters; also known as 6A4-335, apparently.
aerofiles.com (for applications); J47toJ53-54.
Applications: (US) Jovair 4A agricultural, 4E Sedan; McCulloch MC-4C helicopters.

6cyl; 6V-335-A, -B; 210hp@3100rpm; 1956-1964; Wt = 303-305#; TC = 244 on 11/27/56.
Vertically mounted helicopter engine.
AY60; J56-57toJ65-66; W56toW62-63.
Applications: None found.

6cyl; 6V-335-A1A, -A1B; 200hp@3100rpm; 1959-1964; Wt = 320#; TC = 1E2 on 5/11/59.
Vertically mounted helicopter engine with new TC.
AY60; J56-57toJ65-66; W56toW62-63.
Applications: None found.

6cyl; 6VS-335; 225hp@3200rpm; 1959-1964; Wt = 346#; TC = 1E2 on 5/11/59.
Turbocharged version of 6V-335.
AY60; J59-60toJ75-76; W59-60toW62-63.
Applications: None found.

6cyl; 6A-335; 180hp@2800rpm-200@3100; 1963-1976; Wt = 292-328#; TC = 244 on 3/28/63.
Relationship to the 6A4 series is unknown. It was a six-cylinder engine introduced in 1963 to broaden the product range and was developed into the 6A-350 (O-350) with an increase in bore. See, also, the 2A-110 (O-110) and 4A-225 (O-225).
aerofiles.com (for applications); AY60; J64-65toJ75-76; W62-63toW70.
Applications: (France) Socata MS 894 Commodore 220 (marketed in US as Waco Minerva 220). (US) Cessna 172 (STC), 175 (STC); Maule M-4-180 series; Omega BS-12-SR helicopter; Stinson 108-3 (retrofit by Univair under original type certificate); Univair (formerly Stinson) 108-5.

6cyl; 6AS-335; 240hp@3200rpm; 1964-1976; Wt = 358#; TC = 5EA on 4/14/64.
Turbocharged version of 6A-335; approved for horizontal mounting in helicopters under a new TC.
aerofiles.com (for application); J64-65toJ75-76; W62-63toW70.
Applications: (Germany) Wagner Sky-Trac 1 [D-HAJE] & 3 [D-HAJI] helicopters, 4 Aerocar [D-HAGU] roadable helicopter. (US) Omega BS-12 (prototype) [N285D], BS-12-SC helicopters.

6cyl; 6AG-335; 220hp@3400rpm; 1963-1976; Wt = 329#; TC = none.
Geared to N/A.
J64-65toJ64-65; W62-63.
Applications: None found.

6cyl; 6AGS-335; 260hp@3400rpm; 1963-1976; Wt = 410#; TC = none.
Geared to 0.7; Turbocharged and Fuel-injected.
J64-65toJ68-69; W62-63.
Applications: None found.

O-350 -- {4.625 / 3.5 / 352.8} / {117.5 / 88.9 / 5781}

Same bore and stroke as O-120, O-235.
Same stroke as O-110, O-175, O-200, O-225, O-265, O-300, O-315, O-335, O-400, O-595.
Developed from 6A-335 (O-335) with an increase in bore; sold to WSK in 1975 and produced by PZL.

6cyl; 6V-350; 235hp@3200rpm; 1964-1996; Wt = 307#; TC = 9EA on 10/12/64.
Vertically-mounted and fan-cooled helicopter engine.
J67-68toJ75-76 under Franklin; J76-77toJ95-96 under WSK-PZL; W66-67toW70.
Applications: None found.

6cyl; 6A-350; 205hp@2800rpm-235@3200; 1965-2002; Wt = 304-334#; TC = 9EA on 7/29/65.
J67-68toJ75-76 under Franklin; J76-77 to present under WSK-PZL; W66-67toW70.
Applications: (Canada) Firewall-Forward Kit for experimental, homebuilt C.L.A.S.S. BushCaddy L 164 {see the Franklin Aircraft Engines of Colorado Website}. (France) Socata Rallye MS 894 Commodore 220 (later Rallye 220GT; also marketed in US as Waco Minerva 220). (Germany) Hirth Acrostar Mk.II aerobatic; Kaiser Magic aerobatic aircraft. (Italy) SIAI-Marchetti S.205-22/R, -22/M; SIAI-Marchetti/Silvercraft SH-4 helicopter (de-rated to 170hp). (Poland) PZL-Mielic M-20 Mewa (license-built Piper Seneca II), M-26 Iskierka. (US) Jovair 4E Sedan helicopter; Maule M-4-220 series, M-5-220C; STC's for Cessna 170 series, 172 series, 175 series, and Stinson 108 series aircraft and Firewall-Forward Kits for experimental, homebuilt Van's RV-8, -8A and Zenith CH-801 {see the Franklin Aircraft Engines of Colorado Website}.

6cyl; 6AS-350; 235hp@2800rpm; 1968-1996; Wt = 377#; TC = 18EA on 7/19/68.
Turbocharged version of 6A-350.
J67-68toJ75-76 under Franklin; J76-77toJ95-96 under WSK-PZL; W70.
Applications: (Italy) Procair F.15D Picchio.

O-400 -- {4.25 / 3.5 / 397.2} / {108.0 / 88.9 / 6509}

Same bore and stroke as O-200, O-300, O-595.
Same stroke as O-110, O-120, O-175, O-225, O-235, O-265, O-315, O-335, O-350.

8cyl; 8AC-398; 200hp@2600rpm; 1941-1943; Wt = 365#; TC = none.
J41; W41.
Applications: None found.

8cyl; 8ACG-398; 235hp@3500rpm; 1941-1943; Wt = N/A; TC = none.
Geared to N/A for take-off, but shifted to direct drive for cruise as for the 12ACG-596 (O-595).
W41.
Applications: None found.

O-405 -- {4.625 / 4.0 / 403.2} / {117.5 / 101.6 / 6607}

Same bore and stroke as O-540, O-805.
Same bore as O-120, O-235, O-350.
Same stroke as O-425.
This engine has been cited as both the 6ACV-403 and 6ACV-405. The former seems more consistent with Franklin practice and is used here.

6cyl; 6AC-403; 200hp@2750rpm; 1942-1946; Wt = 405#; TC = none.
Military XO-405-1.
AMC.
Applications: None found.

6cyl; 6ACSA-403; 220hp@2750rpm; 1942-1946; Wt = 413#; TC = none.
Supercharged engine; Military XO-405-3.
AMC.
Applications: None found.

6cyl; 6ACGSA-403; 250hp@3200rpm; 1942-1946; Wt = 443#; TC = none.
Supercharged and geared to 0.632; Military O-405-5.
AMC; Fahey USAAF; J45-46toJ47; S; W45toW46.
Applications: None found.

6cyl; 6ACGSA-403; 250hp@3200rpm; 1942-1946; Wt = 454#; TC = none.
Supercharged and geared to 0.632; Military XO-405-7.
AMC; Fahey USAAF; J45-46toJ47; S; W45toW46.
Applications: (US) Culver XPQ-15, XTD3C-1 Target Drones; Fairchild XUC-86B; Fleetwings XBQ-1 Controllable Bomb.

6cyl; 6ACV-403; 235hp@3275rpm; 1942-1946; Wt = 456#; TC = none.
Vertically-mounted and fan-cooled helicopter engine. The applications below had either the Military XO-405-9 (XR-8A) or the Military O-405-9 versions.
aerofiles.com (for applications); AMC; Fahey USAAF; J45-46toJ47; S; W45toW46.
Applications: (US) Doman LZ-1A (modified Sikorsky R-6A); Kellett XR-8, XR-8A; Sikorsky XR-6A, YR-6A, R-6A, R-7 (canceled) helicopters.

6cyl; 6ACV-403; 245hp@3275rpm; 1942-1946; Wt = 456#; TC = none.
Vertically-mounted and fan-cooled helicopter engine; Military XO-405-11.
aerofiles.com (for application); AMC.
Applications: (US) Doman LZ-2A Pelican helicopter.

O-425 -- {4.75 / 4.0 / 425.3} / {120.7 / 101.6 / 6969}

Same stroke as O-405, O-540, O-805.
Developed for the military.

6cyl; 6AG6-245; 240hp@3200rpm, 245@3300 (TO); 1944-1948; Wt = 405#; TC = none.
Geared to 0.623, Military XO-425-5 for airplane propulsion.
AMC; Fahey USAAF; W47toW54.
Applications: (US) Convair XL-13; Republic YOA-15 (canceled; to have 215hp version).

6cyl; O-425-9; 240hp@3200rpm, 245@3300 (TO); 1947-1951; Wt = 413# **; TC = 5E-13, unknown date.
Geared to 0.623; Military production version of XO-425-5 for airplane propulsion with unknown changes; later available through US government surplus.
** It has been reported to the compiler that the actual weight of one example has been measured at about 475# (dry).
AMC; Fahey USAF; J47toJ50-51 (for applications); W47toW54.
Applications: (US) Convair L-13A, L-13B.

6cyl; 6AGS6-245; 250hp@3200rpm; 1944-1948; Wt = 470#; TC = none.
Supercharged and geared to 0.623; Military XO-425-3 for airplane propulsion.
AMC; W47toW54.
Applications: None found.

6cyl; 6V6-245-B16F, 6ACV-245; 245hp@3275rpm; 1944-1958; Wt = 349-369#; TC = 258 in c.1948.
TC is still under Aircooled Motors, not Franklin or WSK-PZL.
Vertically-mounted and fan-cooled helicopter engine; Military XO-425-1; references conflict on whether this engine is direct drive or geared.
AMC; AY51,52; Fahey USAF; J51-52toJ57-58; S; W49toW59-60.
Applications: (US) Sikorsky S-52-2, S-52-3, YH-18, YH-18A, HO5S-1 helicopters.

6cyl; O-425-2; N/A hp@N/A rpm; 1956-1958; Wt = N/A; TC = none.
Supercharged (by a Roots positive-displacement blower); otherwise as the XO-425-1 helicopter engine; references conflict on whether this engine is direct drive or geared.
J56-57toJ57-58.
Applications: None found.

6cyl; 6V6-300-D16FT; 285hp@3275rpm, 300@3275 + Boost (TO); 1955-1960; Wt = 462#; TC = none.
Vertically-mounted, turbocharged, and fan-cooled direct-drive helicopter engine; Military O-425-13; Franklin turbocharger mounted on the airframe.
J55-56toJ57-58; W55toW59-60.
Applications: (US) Sikorsky S-52-2 helicopter (apparently only for tethered flight testing).

O-500 -- {5.0 / 4.25 / 500.7} / {127.0 / 108.0 / 8205}

Franklin also called this engine the 6AL-500 for its displacement. Engines have an extended shaft and a cooling fan for pusher applications. The TC was sold to WSK-PZL, but engines were not produced by them.

6cyl; 6A8-215; 215hp@2500rpm; 1945-1951; Wt = 430-432#; TC = 242 on 12/18/45.
J47; S; W47toW51.
Applications: (Italy) Piaggio P.136-L amphibian twin. (US) Convair (Stinson) Model 106 Skycoach [NX40004]; Republic RC-3 Seabee; Waco Model W Aristocraft [NX34219].

O-540 -- {4.625 / 4.0 / 537.6} / {117.5 / 101.6 / 8809}

Same bore and stroke as O-405, O-805.
Same bore as O-120, O-235, O-350; Same stroke as O-425.

8cyl; 8ACG-538; 300hp@3200rpm; 1942-1945; Wt = 438#; TC = none.
Geared to 0.632; Military XO-540-1.
AMC; Fahey USAAF.
Applications: None found.

8cyl; 8ACSA-538; 300hp@N/Arpm; 1942-1945; Wt = N/A; TC = none.
Supercharged; Military XO-540-7.
AAHSW93 (for N-9MB); AMC; Fahey USAAF.
Applications: (US) Northrop N-9MB.

8cyl; 8ACGSA-538; 330hp@3200rpm; 1942-1945; Wt = 458#; TC = none.
Supercharged and geared to 0.632; Military XO-540-3, O-540-5.
AMC; Fahey USAAF.
Applications: None found.

O-595 -- {4.25 / 3.5 / 595.8} / {108.0 / 88.9 / 9763}

Same bore and stroke as O-200, O-300, O-400.
Same stroke as O-110, O-120, O-175, O-225, O-235, O-265, O-315, O-335, O-350.

12cyl; 12AC-596; 300hp@2600rpm; 1941-1942; Wt = 450#; TC = none.
J41; W41.
Applications: None found.

12cyl; 12ACG-596; 350hp@3500rpm; 1941-1942; Wt = N/A; TC = none.
Geared to N/A for take off, but shifted to direct drive for cruise as for the 8ACG-398 (O-400).
J41; W41.
Applications: None found.

O-805 -- {4.625 / 4.0 / 806.4} / {117.5 / 101.6 / 13,214}

Same bore and stroke as O-405, O-540.
Same bore as O-120, O-235, O-350.

12cyl; 12AC-806; 450hp@N/Arpm; 1942-1945; Wt = N/A; TC = none.
Fahey USAAF.
Applications: None found.

12cyl; 12ACG-806; 456hp@3200rpm; 1942-1945; Wt = 590#; TC = none.
Geared to 0.632; Military XO-805-1.
AMC; Fahey USAAF; J47.
Applications: (US) Interstate XBQ-5 Controllable Bomb.

12cyl; 12ACGSA-806; 500hp@3200rpm; 1942-1945; Wt = 759#; TC = none.
Supercharged and geared to 0.632 (Military XO-805-3), or to 0.587 (Military O-805-5).
AMC; Fahey USAAF.
Applications: None found.

Franklin: Part 1 (to O-300)

CONTENTS

Updated 12/23/07