Hope to gain some information from the collected experience here on VAF.
I have been flying my -7 for about 1 1/2 years now and love the airplane. I use it to commute between jobs and most of the time am willing to trade a few minutes of flight time for the fuel savings of running LOP. My engine will run fine down to more than 100 degrees LOP. and I do so most of the time.
I have been talking to my brother who flies an Aztec and wants to give the LOP operations a try. He has been flying it but does not get the same response to LOP that I get. I know that the engine on the -10 is the same as the one in his Aztec so our question is to the -10 operators " does your IO540 give you the same response as the 4 cly Lycomings when running LOP?"![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Thanks for the Help
Here is what he is seeing on the Aztec.
Here's the deal. I'm trying to run 50 degrees LOP at 65% power.
Yesterday was the third time I've tried it with the same results every time. At
6500 feet MSL power set for 22" and 2200 RPM I'll lean to 12 GPH as directed
by the owners manual. Give the engine time to settle maybe 5 minutes, then
start to lean slowly. The EGT rises steadily until you feel the engine
start to lose power. Power loss is confirmed by a rise in MP and a decrease
in RPM. The EGT will peak when the tach shows about 200 RPM decrease. If
I richen the mixture until I'm back to 12 GPH everything comes back to 22"
and 2200 RPM. I find it physically impossible to fly LOP... that is I don't
think I could maintain altitude IF I were to leave the mixture 50 degrees
LOP. EGT rise is 50 to 75 degrees between 12 GPH and where I can feel the
power starting to diminish.My EGT system is an old analog gauge that
displays only one cylinder at a time but can be selected to each of the six
cylinders. Total variation across the six cylinders is less that 25 degrees. Now
here's another oddity, I'm flying an Aztec and this happens on BOTH
engines. Left engine FI system has less than 10 SMOH and the right is high time.
Can somebody explain what's happening? Is it possibly the fact that I'm
already down low enough in the power band that LOP isn't going to happen?
I'm totally lost and I'll listen to all opinions.
Thanks in advance for helping a non-RV'er
Thanks for reading this far
Dave
I have been flying my -7 for about 1 1/2 years now and love the airplane. I use it to commute between jobs and most of the time am willing to trade a few minutes of flight time for the fuel savings of running LOP. My engine will run fine down to more than 100 degrees LOP. and I do so most of the time.
I have been talking to my brother who flies an Aztec and wants to give the LOP operations a try. He has been flying it but does not get the same response to LOP that I get. I know that the engine on the -10 is the same as the one in his Aztec so our question is to the -10 operators " does your IO540 give you the same response as the 4 cly Lycomings when running LOP?"
Thanks for the Help
Here is what he is seeing on the Aztec.
Here's the deal. I'm trying to run 50 degrees LOP at 65% power.
Yesterday was the third time I've tried it with the same results every time. At
6500 feet MSL power set for 22" and 2200 RPM I'll lean to 12 GPH as directed
by the owners manual. Give the engine time to settle maybe 5 minutes, then
start to lean slowly. The EGT rises steadily until you feel the engine
start to lose power. Power loss is confirmed by a rise in MP and a decrease
in RPM. The EGT will peak when the tach shows about 200 RPM decrease. If
I richen the mixture until I'm back to 12 GPH everything comes back to 22"
and 2200 RPM. I find it physically impossible to fly LOP... that is I don't
think I could maintain altitude IF I were to leave the mixture 50 degrees
LOP. EGT rise is 50 to 75 degrees between 12 GPH and where I can feel the
power starting to diminish.My EGT system is an old analog gauge that
displays only one cylinder at a time but can be selected to each of the six
cylinders. Total variation across the six cylinders is less that 25 degrees. Now
here's another oddity, I'm flying an Aztec and this happens on BOTH
engines. Left engine FI system has less than 10 SMOH and the right is high time.
Can somebody explain what's happening? Is it possibly the fact that I'm
already down low enough in the power band that LOP isn't going to happen?
I'm totally lost and I'll listen to all opinions.
Thanks in advance for helping a non-RV'er
Thanks for reading this far
Dave