My 1951 170A owners manual has only one chart relating pressure altitude (6000 feet) to RPM, BHP, %BHP, and TAS.
Has anyone constructed or have a power settings chart for other altitudes down to sea level?
Also, is there an owners manual issued later than mine dated 4/73?
Thanks for any info.
Jim Heidere
Power settings 170A
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
A unique 170 Owner's Manual (OM) was issued each year the airplane was produced, but very little differed between them among specific models except to update photos.
The 170 B Owner's Manual includes a better/more complete power chart for altitudes from sea level to 12500' (graduated each 2500'). Those figures would/should apply equally to the A model, since they are cruising performance data and both wings would be "clean"...no flaps deployed.
Unfortuately, the B model Owner's Manual depicted in the Member's Only page of these forums did not make the electronic "leap" via the .pdf file and it takes a bit of imagination to interpolate the actual figures, ...but there they are if you wish to see them. (pg 48 of the pdf-file, pg 42 of the manual.)
The Engine Operators Manual also is available in the Members section, and it contains engineering graphs to calculate engine power, but no reference to predicted TAS, (and the graphs are small and difficult to read.)
The major outcome of the B model OM chart is:
@ S.L.: 2450 rpm = 106 hp = 73% pwr = 123 mph = 9.3 gph
2500': 2450 rpm = 95 hp = 65% pwr = 120 mph = 8.4 gph
5000': 2450 rpm = 86 hp = 60% pwr = 117 mph = 7.5 gph
7500': 2450 rpm = 80 hp = 55% pwr = 116 mph = 7.0 gph
10.0K': 2450 rpm = 76 hp = 53% pwr = 114 mph = 6.7 gph
12.5K': 2450 rpm = 73 hp = 51% pwr = 113 mph = 6.4 gph
While your '51 Owner's Manual seems to have been printed in '73, keep in mind that document was actually a "convenience reprint" sold by Cessna's Marketing Department. As Cessna made subsequent reprints, they consolidated data and the manuals became more and more generic. Therefore a "later" manual would not be expected to have "better" or more accurate data. (Testing is expensive, and after a mfr ceases production of a particular model aircraft, they rarely revisit the issue to accurize data unless safety issues are raised. The performance "data" in the Owner's Manual is advisory only, and not FAA approved data.)
The 170 B Owner's Manual includes a better/more complete power chart for altitudes from sea level to 12500' (graduated each 2500'). Those figures would/should apply equally to the A model, since they are cruising performance data and both wings would be "clean"...no flaps deployed.
Unfortuately, the B model Owner's Manual depicted in the Member's Only page of these forums did not make the electronic "leap" via the .pdf file and it takes a bit of imagination to interpolate the actual figures, ...but there they are if you wish to see them. (pg 48 of the pdf-file, pg 42 of the manual.)
The Engine Operators Manual also is available in the Members section, and it contains engineering graphs to calculate engine power, but no reference to predicted TAS, (and the graphs are small and difficult to read.)
The major outcome of the B model OM chart is:
@ S.L.: 2450 rpm = 106 hp = 73% pwr = 123 mph = 9.3 gph
2500': 2450 rpm = 95 hp = 65% pwr = 120 mph = 8.4 gph
5000': 2450 rpm = 86 hp = 60% pwr = 117 mph = 7.5 gph
7500': 2450 rpm = 80 hp = 55% pwr = 116 mph = 7.0 gph
10.0K': 2450 rpm = 76 hp = 53% pwr = 114 mph = 6.7 gph
12.5K': 2450 rpm = 73 hp = 51% pwr = 113 mph = 6.4 gph
While your '51 Owner's Manual seems to have been printed in '73, keep in mind that document was actually a "convenience reprint" sold by Cessna's Marketing Department. As Cessna made subsequent reprints, they consolidated data and the manuals became more and more generic. Therefore a "later" manual would not be expected to have "better" or more accurate data. (Testing is expensive, and after a mfr ceases production of a particular model aircraft, they rarely revisit the issue to accurize data unless safety issues are raised. The performance "data" in the Owner's Manual is advisory only, and not FAA approved data.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.