My POH says that my max rpm is 2700 continuous, I always take off with that but back off to 2500 once I reach pattern height as I continue to climb. At the same time I back the manifold pressure back to 25". Seems that as I read more and talk to more guys, I don't need to back off the MP because it is going to fall back and I am not going to hurt the engine by leaving the MP alone and bringing the rpm back to 2500. Can someone shed some light on this in laymens terms?

My next question is about leaving the rpms at 2700 for climb. When we departed Jeffco two weeks ago I was at 3100lbs 30deg F and 6700'. I was climbing at 120mph and 2500rpm's and struggling to get 450fpm. Could I have left the rpm's at 2700 longer? According to the POH I can but what say you io520BA guru's? I would have had a little better climb rate had I left them, I started to get a little nervous as I turned South and didn't seem to be climbing very well.

Any light you can shed is appreciated.

I leave throttle full and RPM's full all the way until 1 or 2 minutes after reaching my altitude. Then I pull back to 2500 RPM and leave MP wide open.

My engine runs cooler at 2700RPM in the climb. The guys at FlightSafety confirmed this for me. They said literally "well, of course it runs cooler, you have less load on the engine at 2700rpm than you at 2500rpm".

Be nice to the neighbors around the airport. After takeoff use WOT and pull the RPMs back to 2650 for noise. Climb to desired altitude, level then close the cowl flaps and leave MP and RPM alone for 2 minutes.

At Cruise use WOT and rpms @ 2500. Lean between 70 to 100 degrees LOP. Your engine will be happier and you can use the money that you saved on fuel to take your wife to dinner.

Wes: Of course you leaned for best power at Jeffco, right?

Otherwise, LEAVE IT AT 2700RPM. Your HP is directly related to your prop RPM so any decrease is robbing you of precious power.

Paul

I don't need any of your lip Paul!!!!!!!

Opps! Forgot to put after that last post.

[ Removed ]

Wes: I knew you were joking.

Glad to see you here on the forum.

Paul

It's important to pull the MP back to 25 inches as quickly as possible.

Otherwise you might inadvertently be in an oversquare condition!








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My SOP is that when cleared to climb or in uncontrolled airspace, I leave RPM at max rated and WOT. My fist is however, placed on the mixture levers and my eyes keep watch on the JPI EGTs. Keeping EGTs around 1250-1300F. My rate of climb performance at the max rpm is quite impressive compared to a reduced RPM (gee big surprise ) and this is excellent when you can climb from sea level on up to 8,9, or 10,000' without ATC or airspace issues.

After reaching cruise altitude, I pull MP, RPM and FF back to my desired cruise set up .

My typical cruise altitudes are rarely less than 8000'.

Of course, if I am flying an IFR departure and getting small step climbs, I just pull it all back and save my gas and engines until they are done vectoring me and give me clearance to climb to filed altitude.

Just a few thoughts on what works for me.

Mike

I fly my Bonanza similar to a C172, push all the knobs in, climb to altitude. I will adjust the mixture on the climb. I will also sometimes get around to pulling the RPM back to 2500 to 2600 RPM, but I am in no hurry.

I did a calculation once that proved to me that the total number of revolutions of the engine were fewer if I climbed to altitude with the Prop at 2700 RPM and that I was further down the road than if I reduced the RPM's to 2500 for a cruise climb. I got to altitude sooner and started the high speed cruise phase sooner. A 7 or 8 percent increase in RPM and climb power don't make any difference in airspeed, but make a very large increase in climb performance.