As of today, I’ve logged 7.3 hours in the aircraft. The airplane is flying well, but there have been some maintenance issues. So lots, to cover. We’ll cover things one topic at a time. First, lets take a look at engine performance so far.
First up, CHTs. Unfortunately, I did forget an SD card on a couple of my flights, so they are not all represented here. But we’ll start with first flight on June 13. You can see the maximum CHT reached is 383 after takeoff. The spread between highest and lowest is 52 degrees. Cylinder 3 is running the hottest – with the cylinder directly in front of it, running the codes. There is only 9 degrees between the two cylinders (2 & 4) on the left side of the engine.
I missed logging the date from a 1.1 hour flight on the 16th. So the next flight shows the engine after it has 2.2 hours on it. I have also added some metal foil tape to cylinder 1 to try to decrease its airflow, and increase airflow to cylinder 3. The CHT spread is now 41 degrees but between cylinder 3, and cylinder 4. The spread between 1 & 3 has dropped to 23 degrees. I also added some tape to cylinder 2, which was a mistake. All in all these numbers are really really good for an engine during break in!
I did two flights on the 18th, and you can see the CHT trend remains the same.
I missed the SD card again for a flight on the 19th. I did do a compression test after the flights on June 18th. Cylinders 1, 3, & 4 got 78/80. And cylinder 2 scored a 76/80. Removing all the bottom plugs showed them to be mostly dry, with cylinder #2, showing a little bit wet.
Now the plane went into a maintenance phase to correct several issues, that I will cover later.
Here is the CHT data from today, July 2nd. CHT max is 353. The maximum delta is 35 degrees. Cylinder 1 to 3 is now 17, and Cylinder 2 to 4 is 5 degrees. The numbers are all trending in the right direction. I’d like to get CHT 3 a bit lower, so I’ll play with that. Either way, what I take from these numbers are 2 things. First, this engine is cooling very well. Every flight has been maximum power for takeoff and initial climb, followed by periods of 25 squared or 24 squared. The engine has been run hard, and she’s running very cool! Second, as the CHTs are coming down, this is a good indication that proper break-in is occurring.
Now lets take a look at oil temps. I’m not going to do as many graphs for this one, as oil temps have remained solid, and are not indicative of break-in. Here is the latest flight. Oil temp basically between 176 and 189. 180 is optimum, so oil temps are right where I want them. Angle valve engines are known for running cooler CHTs and hotter oil temps. For this reason, I installed the bigger oil cooler, and so far that decision seems to be good all around. This baby shouldn’t have any problems with temperatures!!!
I have some preliminary speed data, but all the while I’m screaming around rich of peak for engine break-in, they should be taken with a grain of salt. Here are the speeds from a flight where I did the airspeed box.
At 25 squared I was getting about 181 to 184 KTAS, and at 24 squared I was getting right around 170 KTAS.
I have done a couple of stalls, and collected that data. Here you can see a stall series I did on June 18th. Stall with full flaps was at 53 KTAS, and 48.5 KIAS. I’ve only done a couple stalls, really just to establish safety of flight for the landing pattern. I will return to much more in-depth stall testing, when I’m comfortable that the majority of engine break-in is complete, and going to lower power settings will not harm break-in.
Ok. Now some fun photos and reports.
Some views from the cockpit on June 18th. It is such an absolute thrill to have my own airplane in the air!
And from today, July 2nd.
Last note on in-flight performance. Between the last flight on June 19th, and today’s flight on July 2nd. I did a lot of maintenance items, which I will cover in a subsequent post. I did do the on-ground configuration of the auto-pilot. So today was a good opportunity to give that an initial test. There are some procedures for doing in-air setup. Mainly centered around gains and torques. Today’s testing seemed to show everything working perfectly. I did heading and altitude holds, as well as turns, climbs, descents and even let the flight director pick up navigation to a direct waypoint. I don’t think much, if anything, will need to be tweaked in terms of gains, or torques. Auto-trim is currently turned off, so we’ll circle back to that at a later time too.