Cont O300A in early 172 - only making 2300rpm in Vy climb

[jimmyjack]

This sound about right? I know very little about it, but this seems on the low side. It's actually a little higher than Vy....80mph indicated, yielding 500-700 fpm in 50deg F day, but 2250-2300rpm is all I get.

Otherwise, plane flies nice. Leveling off, will slowly pick up to 2500 to 2650, as the POH dictates it should.

 

[warthog1984]

What's static run-up?

 

[Tom-D]

This sound about right? I know very little about it, but this seems on the low side. It's actually a little higher than Vy....80mph indicated, yielding 500-700 fpm in 50deg F day, but 2250-2300rpm is all I get.

Otherwise, plane flies nice. Leveling off, will slowly pick up to 2500 to 2650, as the POH dictates it should.

Really depends on what prop is installed, and if the engine is making full power.

 

[iflyvfr]

And if the tach is correct. There's an iOS app that will check engine RPMs and in my experience it was accurate.

 

[Dan Thomas]

This sound about right? I know very little about it, but this seems on the low side. It's actually a little higher than Vy....80mph indicated, yielding 500-700 fpm in 50deg F day, but 2250-2300rpm is all I get.

Otherwise, plane flies nice. Leveling off, will slowly pick up to 2500 to 2650, as the POH dictates it should.

Sounds low, but check that tach. Do a static runup at full power and see if you get an honest reading as per the TCDS, here:

http://www.airweb.faa.gov/Regulator...3357f6c86257ea4004e8ae6/$FILE/3A12_Rev_84.pdf

 

[Henning]

That sounds about right. If it makes both speed and RPM in level flight, then a couple hundred loss, especially on a mechanical tach, I would call within parameters.

 

[ahkahn]

That sounds about right.

Where have you been, Henning?!?! It's been a while!

 

[Fearless Tower]

What's static run-up?

That would be my question.

Don't know about the 172, but in the 170 with O-300, the static RPM should be 2280. It is not unusual to only see around 2300 RPM in an initial climb.

 

[Tom-D]

That would be my question.

Don't know about the 172, but in the 170 with O-300, the static RPM should be 2280. It is not unusual to only see around 2300 RPM in an initial climb.

From the type certificate, it can be as low as 2230 and as high as 2480 RPM Static.. depending upon which propeller is installed and at what pitch.

With out the prop model, and pitch, we can't tell if it is good to go or not.

 

[Fearless Tower]

From the type certificate, it can be as low as 2230 and as high as 2480 RPM Static.. depending upon which propeller is installed and at what pitch.



With out the prop model, and pitch, we can't tell if it is good to go or not.

Interesting. The AFM specifies 2280 for both Mcauley (metal) and Sensenich (wood).

 

[RickG]

From the type certificate, it can be as low as 2230 and as high as 2480 RPM Static.. depending upon which propeller is installed and at what pitch. Without the prop model, and pitch, we can't tell if it is good to go or not.

For reference, here's a link to the Type Certificate Data Sheet 3A12
http://rgl.faa.gov/Regulatory_and_G...3357f6c86257ea4004e8ae6/$FILE/3A12_Rev_84.pdf