jetcareers - View Single Post - Arrow climb power - 25-squared?

pilot602 · August 22nd, 2003, 15:59

You have two seperate issues here.

1) Flying square.

2) Lower power settings for climb out.

1) Flying square is a throw-back to the radial engine days. The radials (and only because of the materials used at the time ... not the fact they were radials) tended to blow cylinders when MP exceeded RPMs by very much. However, nowadays (since about WWII on up) MP over the RPM is generally accepted and a proven way to increase fuel efficiency. Lindbergh used the technique to prove the P-38 actually had a lot more range than it was getting. However, only use what's printed in the power chart. Excessive MP or arbitrarily setting MP above RPM can still cause damage if it's too extreme.

However, flying square is an easy way to transition into an unfamiliar aircraft because so long as you keep it squared you cant blow anything up.

2) Lower power settings on climbout help with engine wear and tear. In most rentals no one cares and every one just invokes "rental power" and redlines everything they can. But if you own an aircraft, or really want to operate an aircraft correctly, you don't want to just redline the thing. We generally carry redline till about 1,000 AGL and then bring it back to a 25/25 climb. This is on an Apache (O-320s).

August 22nd, 2003, 15:59	#2
pilot602 Old Skool Join Date: Oct 2001 Location: who haa Posts: 3,752	Re: Arrow climb power - 25-squared? You have two seperate issues here. 1) Flying square. 2) Lower power settings for climb out. 1) Flying square is a throw-back to the radial engine days. The radials (and only because of the materials used at the time ... not the fact they were radials) tended to blow cylinders when MP exceeded RPMs by very much. However, nowadays (since about WWII on up) MP over the RPM is generally accepted and a proven way to increase fuel efficiency. Lindbergh used the technique to prove the P-38 actually had a lot more range than it was getting. However, only use what's printed in the power chart. Excessive MP or arbitrarily setting MP above RPM can still cause damage if it's too extreme. However, flying square is an easy way to transition into an unfamiliar aircraft because so long as you keep it squared you cant blow anything up. 2) Lower power settings on climbout help with engine wear and tear. In most rentals no one cares and every one just invokes "rental power" and redlines everything they can. But if you own an aircraft, or really want to operate an aircraft correctly, you don't want to just redline the thing. We generally carry redline till about 1,000 AGL and then bring it back to a 25/25 climb. This is on an Apache (O-320s).