Sensenich Propeller Mfg. Co.

Minimum Diameters and RPM Restrictions (Placards) Allowable For Sensenich Propellers

NOTE: The reducing of aluminum propeller diameters below their recommended limits will cause propeller failures! For this reason, we have created this chart. These diameters are superseded by your airframe manufacturer's type certificate. Homebuilt / Kit_Plane builders should follow these recommendations.

Propeller Model Spacers (in inches) Engine Model Max. Dia. Min. Dia. Placards

69CK 0 to 3.0 Continental O-200-A 69 67 None

70CM6, 70CM7 0 to 4.0 Lycoming 0-320 Series 70 68 No operation above 2600 RPM

72CK 0 Continental A65 Series 72 70 None

72CK 0 Continental C75 Series 72 70 None

72CK 0 Continental C85 Series 72 70 None

72CK 0 Continental C90 Series 72 70 None

72CK 0 to 3.0 Lycoming O-235 9.70 to 1 Compression Ratio or less. 125 hp @ 2800 rpm or less 72 70 None

72CC 0 to 1.5 Franklin 4A-235-B 72 70 None

72FM8-1 0 to 4 Lycoming O-360 71 69 None

74DM6, 74DM7 0 to 3.5 Lycoming O-320 Series 160 hp @ 2700 RPM or less 74 72 None

74DM6, 74DM7 0 to 3.5 Lycoming O-290-D, -D2 -D2B series 74 72 None

74DC 0 Franklin 6A4-150-B4 74 72 Avoid continuous operation between 2150 & 2250 rpm on ground and in flight

74DR 0 Franklin 6A4-165-B3 74 72 Avoid continuous operation between 2150 & 2250 rpm on ground and in flight

74DR-1 0 Continental C-125-2 73 71 None

74DR 0 Continental C-145 Series or Continental O-300-A, B, 145 hp @ 2700 RPM or less 74 72 None

74DC 0 Continental O-300-C, -D, and -E, 145 hp @ 2700 RPM or less 74 72 None

74DC 0 Continental IO-346-A 165 hp @ 2700 RPM or less 74 74 None

74CK 0 Continental A65 Series 6.3 to 1 Compression Ratio or less, 65 hp @ 2350 RPM or less 74 70 None

74CK 0 Continental A75 Series 6.3 to 1 Compression Ratio or less, 75 hp @ 2600 RPM or less 72 70 None

74CK, 76AK-2 0 Continental C75 Series 6.3 to 1 Compression Ratio or less, 75 hp @ 2275 RPM or less 74 72 None

74CK 0 Continental C85 Series 6.3 to 1 Compression Ratio or less, 85 hp @ 2575 RPM or less 72 70 None

74CK 0 Continental C90 Series 7 to 1 Compression Ratio or less, 90 hp @ 2475 RPM or less 74 70 None

74CK 0 Lycoming O-145 Series 6.51 to 1 Compression Ratio or less, 65 hp @ 2550 RPM or less 72 68 None

76AK-2 0 Continental A65 Series 6.3 to 1 Compression Ratio or less, 65 hp @ 2350 RPM or less 74 72 None

76AK-2 0 Continental C85 Series 6.3 to 1 Compression Ratio or less, 85 hp @ 2575 RPM or less 74 72 None

76AK-2 0 Continental C90 Series 7 to 1 Compression Ratio or less, 90 hp @ 2475 RPM or less 74 72 None

76AM6-2 76AK-2 0 to 1.5 Lycoming O-235 Series 6.75 to 1 Compression Ratio or less, 108 hp @ 2600 RPM or less 74 70 None

76AM6-2 0 Lycoming O-290-D 74 72 None

76AM6-2 0 Lycoming O-290-D2 74 72 None

76EM8 0 to 4.0 Lycoming O-360 HOLLOW CRANKSHAFTS ONLY! 180 HP @ 2700 RPM (Excludes engines with suffixes having a digit "4" or higher in the second position) 76 76 Avoid continuous operation between 2150 and 2350 RPM

76EM8 0 to 4.0 Lycoming O-360 SOLID CRANKSHAFTS ONLY! 180 HP @ 2700 RPM (Engines with suffixes having a digit "4" or higher in the second position 76 76 None

80BM8 (Obsolete) 0 Lycoming O-540-B4B5 235 hp @ 2575 RPM or less 80 78 None

Propeller Model	Spacers (in inches)	Engine Model	Max. Dia.	Min. Dia.	Placards
69CK	0 to 3.0	Continental O-200-A	69	67	None
70CM6, 70CM7	0 to 4.0	Lycoming 0-320 Series	70	68	No operation above 2600 RPM
72CK	0	Continental A65 Series	72	70	None
72CK	0	Continental C75 Series	72	70	None
72CK	0	Continental C85 Series	72	70	None
72CK	0	Continental C90 Series	72	70	None
72CK	0 to 3.0	Lycoming O-235 9.70 to 1 Compression Ratio or less. 125 hp @ 2800 rpm or less	72	70	None
72CC	0 to 1.5	Franklin 4A-235-B	72	70	None
72FM8-1	0 to 4	Lycoming O-360	71	69	None
74DM6, 74DM7	0 to 3.5	Lycoming O-320 Series 160 hp @ 2700 RPM or less	74	72	None
74DM6, 74DM7	0 to 3.5	Lycoming O-290-D, -D2 -D2B series	74	72	None
74DC	0	Franklin 6A4-150-B4	74	72	Avoid continuous operation between 2150 & 2250 rpm on ground and in flight
74DR	0	Franklin 6A4-165-B3	74	72	Avoid continuous operation between 2150 & 2250 rpm on ground and in flight
74DR-1	0	Continental C-125-2	73	71	None
74DR	0	Continental C-145 Series or Continental O-300-A, B, 145 hp @ 2700 RPM or less	74	72	None
74DC	0	Continental O-300-C, -D, and -E, 145 hp @ 2700 RPM or less	74	72	None
74DC	0	Continental IO-346-A 165 hp @ 2700 RPM or less	74	74	None
74CK	0	Continental A65 Series 6.3 to 1 Compression Ratio or less, 65 hp @ 2350 RPM or less	74	70	None
74CK	0	Continental A75 Series 6.3 to 1 Compression Ratio or less, 75 hp @ 2600 RPM or less	72	70	None
74CK, 76AK-2	0	Continental C75 Series 6.3 to 1 Compression Ratio or less, 75 hp @ 2275 RPM or less	74	72	None
74CK	0	Continental C85 Series 6.3 to 1 Compression Ratio or less, 85 hp @ 2575 RPM or less	72	70	None
74CK	0	Continental C90 Series 7 to 1 Compression Ratio or less, 90 hp @ 2475 RPM or less	74	70	None
74CK	0	Lycoming O-145 Series 6.51 to 1 Compression Ratio or less, 65 hp @ 2550 RPM or less	72	68	None
76AK-2	0	Continental A65 Series 6.3 to 1 Compression Ratio or less, 65 hp @ 2350 RPM or less	74	72	None
76AK-2	0	Continental C85 Series 6.3 to 1 Compression Ratio or less, 85 hp @ 2575 RPM or less	74	72	None
76AK-2	0	Continental C90 Series 7 to 1 Compression Ratio or less, 90 hp @ 2475 RPM or less	74	72	None
76AM6-2 76AK-2	0 to 1.5	Lycoming O-235 Series 6.75 to 1 Compression Ratio or less, 108 hp @ 2600 RPM or less	74	70	None
76AM6-2	0	Lycoming O-290-D	74	72	None
76AM6-2	0	Lycoming O-290-D2	74	72	None
76EM8	0 to 4.0	Lycoming O-360 HOLLOW CRANKSHAFTS ONLY! 180 HP @ 2700 RPM (Excludes engines with suffixes having a digit "4" or higher in the second position)	76	76	Avoid continuous operation between 2150 and 2350 RPM
76EM8	0 to 4.0	Lycoming O-360 SOLID CRANKSHAFTS ONLY! 180 HP @ 2700 RPM (Engines with suffixes having a digit "4" or higher in the second position	76	76	None
80BM8 (Obsolete)	0	Lycoming O-540-B4B5 235 hp @ 2575 RPM or less	80	78	None

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Sensenich Propeller Mfg. Co.

Minimum Diameters and RPM Restrictions (Placards) Allowable For Sensenich Propellers

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