The International Cessna 170 Association

Hi I’m having trouble getting max rpm on takeoff. I can only get 2400 rpm on takeoff and in flight ? Should I not be able to get 2700 on takeoff?? I just put new rings an did all the valves new mags plugs an carb rebuild I’m stumped any idas would be greatly appreciated thanks

More info is required.

Do you have a C-145 and a prop allowed by the TCDS? If so you may be getting more RPM than you should depending on when your seeing 2400 RPM and exactly what prop you do have.

Bet you might have a Lycoming or Continental or maybe even a Franklin with one of many props and governors. We need to know what you have in order to comment.

Propeller
(a) McCauley 1A170 33lb.
Static r.p.m. at max. permissible throttle setting:
Landplane: Not over 2330, not under 2230
Seaplane (Models 170A and 170B): Not
over 2525, not under 2300.
No additional tolerance permitted.
Assuming you have a stock airplane this is the propeller limits from the Type Certificate Data sheet. You will almost never see 2700 RPM without diving the airplane and unloading the propeller or having a flatter pitched propeller such as the 8042 prop I once had on my 170A. It allowed me to get 2700 HP on the takeoff roll. I could also exceed 2700 RPM in cruise flight. Prior to that with the stock propeller I would only see about 2300 RPM static and is I recall about 2500 in cruise. Thus you never get 145HP. Topic is discussed many times on the Forums here.

Metal Master wrote:... It allowed me to get 2700 HP on the takeoff roll.

And I thought your IO-360 conversion was amazing! I want to see some pictures of that Pratt & Whitney R4360-4 conversion!