New Engine: First Test Flight
posted Aug 29, 2007
After what seemed like forever, the Lycoming factory rebuilt engine is finally on the Mooney and the first test flight went off without a hitch on August 13th. Well, that’s not 100% true. There was a hitch, but not with the engine.
After doing a very thorough preflight inspection, Nancy and I pulled the plane out of the hangar, closed the hangar doors, and began going through the pre-start checklist. This was exciting, we were about to hear the sound of our new engine. “Seats adjusted and Seat Belts….SET.” Hmmm … no, wait. There was something wrong. The shoulder harness wasn’t going all the way across my chest. And the buckle part of the seat belt was supposed to be in my right hand, not the left. What was going on here?
It took us about a minute to figure out the problem. The left and right front seats were swapped around. The whole saga of needing to replace the engine started back in May during the annual inspection of the airplane. As part of that inspection, our mechanics pulled the seats out of the airplane to get better access inside. Somebody didn’t label the seats, and they got put back in the airplane in the wrong spots. A very easy mistake to make. The seats are identical except for the seatbelt position.
We hadn’t flown the Mooney in four months and we were both anxious to get back in the air with our favorite plane. As soon as we discovered the seat-swap issue, I knew we wouldn’t be able to fly. Given that this was my very first new-engine test flight, shoulder harnesses were required. However, it was funny and a little sad to watch as Phil’s desire to fly temporarily overpowered his sense of logic. He tried fitting the shoulder harness in several positions thinking he could make it work. After about 30 seconds, Phil agreed it was time to climb out and push the Mooney back into the hangar. We both sighed with disappointment.
All dressed up and no place to go
Even though it was around 6 pm on a Monday, Mike (the owner of our maintenance shop) hadn’t left for the day. He came right over and swapped the seats back into their correct positions within minutes. He wasn’t the one who took the seats out, but he was going to be sure to talk to the person that did and make sure they understood why it’s important to label the seats left and right. I’m pretty sure he was also going to explain how it’s a bad idea to cut into the boss’s evenings.
With the seats back in their correct locations, we were able to go through the entire pre-start checklist with no problems. It was time for the moment of truth. After Nancy shouted, “Clear!” through the open door, I turned the key and the new engine purred in response. The engine was noticeably smoother than the previous one (and smoother than any other piston airplane I’ve been in). I tried not to get too distracted by the sweet sound of the engine humming, and focused my attention on all the engine instruments. All indications were in the green and the JPI engine monitor confirmed that all 4 cylinders were running smoothly.
We completed the rest of the pre-takeoff checks which involved ensuring the two independent ignition systems were operating, checking the operation of the freshly overhauled propeller governor, and making sure everything was ready for flight.
Now was the moment of truth. The winds were favoring runway 29 at Nampa. The emergency landing options are somewhat limited when departing that runway. I briefed Nancy on my take off and emergency plan, “I’ll climb out at Vx which is 76 mph, when we get 100 feet up, I’ll pitch down to Vy which is 101 mph and retract the gear and flaps. If we have an engine failure on take off, I’ll either land on the available runway ahead or if that’s not an option, I’ll turn about 30 degrees right towards the golf course.” If the there were no problems during the take off, than plan was to orbit the airport at 5,500 feet MSL which is 3,000 feet AGL. Orbiting the airport would allow us to land back on the runway in case anything went wrong with the new engine.
We scanned for traffic and then rolled onto runway 29. I verified that the boost pump, landing light, strobes and transponder were all on. Wing flaps, cowl flaps and trim were set. I slowly added full power and the engine’s gentle purr turned into a powerful growl, but it still continued to run much smoother than any piston airplane I’ve ever been in. I talked out loud as much for my benefit as for Nancy’s, “airspeed alive, engine instruments green, rotating and pitching for 76.” We were climbing nicely at Vx (76) and once we had 100 feet of altitude, I pitched down to Vy (101) and retracted the flaps and gear. Even though the temperature was about 90°F we were getting a climb rate of about 1,000 feet-per-minute.
The cylinder head temperatures were quickly climbing, but this was normal. Lycoming’s engine break-in instructions said to expect this, especially during the first 10 hours or so of flight. Part of the purpose of the engine break in is to properly seat the piston rings and this process generates extra heat. The JPI engine monitor started flashing when the cylinder head temperature on#3 got above the 400°F limit I had previously programmed. By this point we were about 500 feet in the air and the engine was operating very well, so I felt comfortable lowering the nose a bit to provide more cooling air to the engine. The CHTs began to work their way back down towards 380°F where I prefer to see them.
Flying in Circles
We made a gradual climb to 5,500 feet to keep lots of air flowing over the engine. Once there I made sure the engine power was set to the break-in recommendation of 75%, and then we orbited the airport for about 30 minutes.
After we both felt confident that the engine was going to keep running, we flew south for a bit and toured around Lake Lowell and the Snake River, keeping emergency landing sites nearby at all times. As we headed back towards the Nampa airport, we were treated to a beautiful sunset (which are best seen from the air).
We’ve had a few more local flights with the new engine now, and it’s still running great. We had one minor problem with the alternator belt getting slightly loose and squealing at low power settings, but our mechanics fixed that right away.
Once the break-in of the new engine is complete (which will take 25 to 50 flying hours) we’ll be able to start taking longer trips again. Stay tuned for further updates.