RPM During Takeoff Power Application

[Frankster13]

When I apply full power for takeoff the RPM on my Lycoming IO-390 with a constant speed prop is at 2670. Is this value within standards or excessive?

 

[georgemohr]

Spot on.

 

[Taltruda]

Depends.. is there any surging when you apply takeoff power? Does it eventually get to 2700 by liftoff? Backing out the governor screw one turn should give you the extra 30 rpm, while tightening The propeller low pitch stops will lower your static RPM to 2650.

 

[andoman]

+1.
Put another way: You need to verify that the flat pitch stop is limiting the 2670 static RPM vice the governor.
Your RPM is close for a static RPM and ideally should inch up to 2700 at liftoff.
See Taltruda’s recent thread in the Prop sub-forum.

 

[Carl Froehlich]

When I apply full power for takeoff the RPM on my Lycoming IO-390 is at 2670. Is this value within standards or excessive?

Do you have a FP or CS prop?

Carl

 

[Desert Rat]

Do you have a FP or CS prop?

Carl

And what brand? The static number isn't universal. Whirlwind, for example says that static full power RPM on the 300-72 should be 2550. I only know that because I was looking at my install manual today.

 

[georgemohr]

And what brand? The static number isn't universal. Whirlwind, for example says that static full power RPM on the 300-72 should be 2550. I only know that because I was looking at my install manual today.

That's a surprise to me! Seems very low.

 

[Desert Rat]

That's a surprise to me! Seems very low.

I agree, but it's right there in section 4.1 of the installation manual, right before it tells you how to adjust the low pitch stop.