Flights 2, 3, 4, 5, and 6

Spring and the new propeller governor for my Bede BD-4C airplane arrived so I took three afternoons off of work and went flying. 😀 I now have six flights and a total of 4.2 hours in my airplane. To say that this has been an amazing week would be an amazing understatement.

Forgive me for uploading rough photos. I have been spending my time flying and working through the data from the test flights and resolving the squawks that arose. There have not been enough hours in the day to edit the photos properly.

Replacing the Propeller Governor

As I mentioned previously, I needed to replace the propeller governor on my airplane. Here is a photo of the engine, ready for surgery.

The governor is on the back of the engine, sandwiched between it and the firewall. Fortunately, the engine mount on a BD-4C can be detached on one side and the engine swung away, allowing easier access. I supported the weight of the engine with a hoist and disconnected the heater hose (orange tube at the bottom of the engine). If you click on that picture and look closely at the black engine mount tubes where they meet the fuselage, you will see that they are actually disconnected.

Where is the governor? I’m glad that you asked.

Removing the old governor was a matter of disconnecting the control cable and removing the four nuts holding the governor in place. I was surprised that the gasket came off cleanly, too.

The new PCU5000X governor is slightly smaller than the old one.

I bolted it in place and attached the control cable.

Then I reattached the engine mount and the heater hose and was ready to fly. This job only took a couple of hours on Monday evening so Tuesday was for…

Flight 2

My first flight of N2468Z was over a month ago and lasted only 15 minutes. My second flight picked up where that one left off and this time, it went without a hitch.

I was up for just over 30 minutes. I confirmed that the airplane was controllable and returned to check “under the hood.” In more detail, I found the following:

• The engine was backfiring while taxiing, not just when it was cold but also after the flight.
• I needed left rudder and right stick to maintain level flight.
• I could easily cruise at 130 knots, which is 146 MPH. That was with 23″ of manifold pressure and 2300 RPM.
• The stabilator trim kept creeping so that the airplane kept trying to nose up, instead of maintaining level flight.
• The manifold pressure “gauge” display on the EFIS screen was only half working. The numerical display was right but the analog needle never moved.
• The idle RPM seemed to be set a bit too low.

We pulled the top of the cowling off and, other than a small leak from a fitting on the oil cooler, everything looked OK. I reinstalled the cowling. I also adjusted the rudder trim tab so that I would not have to continuously press on the left rudder pedal. And since it was still early in the afternoon, I took off for…

Flight 3

The purposes of this test flight were to test the flaps and perform a rough check of the pitot-static system. In English:

• Do the flaps work to assist in landing at lower speeds? and
• Does the airplane accurately display speed?

These two functions are important for safe landings.

The flight took 1.4 hours and I was busy for the first hour. After that, I took some time to just enjoy being in the sky. I confirmed that the flaps were working right and collected data on the airspeed indicator.

The left wing was still heavy but now I needed right rudder, instead of left, to maintain wings-level flight.

Later analysis showed that the airspeed indicator is accurate (which I expected) and that I have the oil pressure set a bit too high. I have just over 90 PSI after the engine is warmed up. Lycoming says that the maximum is 95 so I am within limits but I think that I will dial it back a few PSI just to provide some headroom.

Flight 4

Before flying on Wednesday, I tightened the tension nut on the stabilator trim. I adjusted the right flap upward a bit, so that the right wing would generate less lift, to try to balance out the “left wing heavy” condition. I also moved the rudder trim tab to a middle position, between where it started and were I had it set for flight 3.

Flight 4 was a quick five minute up, around the pattern, and land again. That was enough to determine that a) the rudder was fine, and b) the left wing was still heavy.

I adjusted the left flap down, generating more lift from the left wing (and adding a tiny bit of drag).

Flight 5

The fifth flight was a success. The left wing was only slightly heavy and I thought that it might be simply a result of there only being one person in the plane (me) and I was sitting on the left side. The rudder was spot on.

I headed north from the airport and spent 20 minutes just flying around, er, testing the plane to be sure that it was controllable or something. It was a gorgeous afternoon to be in the sky!

Flight 6

I returned to the airport today for the sixth flight. Before the flight, I updated the settings in the EFIS to fix the manifold pressure gauge. It turned out that the needle was set to display values from 30 to 42 inches of pressure. I changed it to display 15 to 32 inches. It works great now. I also Bluetooth paired my iPad with my PS Engineering PDA360EX audio panel so that I could hear Foreflight’s audio warnings through my headset.

Flight 6 was high risk. The purpose was to check wings-level stalls, to determine several things:

• At what speed does the airplane stall in each configuration?
• What warnings does the airplane give before it stalls?
• How does the airplane behave when it stalls?
• How easily can I recover from a stall (get flying again) and how much altitude do I lose?

Everything went fine, though I was on “high alert” the whole time and came back from the flight pretty tired.

• My airplane stalls between 65 and 61 knots, depending on configuration.
• I got plenty of warning, mostly with the controls getting mushy (less responsive) and only a small amount of buffeting. Just before the stall, the fuselage skin started to oil can and that was plenty loud.
• When the airplane starts to stall, it starts to sink rapidly. If I hold the stick pulled all the way back, letting the stall fully develop, the nose drops sharply and the left wing drops. (Clearly I need a bit more adjustment in the flaps.)
• The plane resumes flying promptly, as soon as I stop pulling backward on the stick.

Here are a couple of graphs that I made of the data from the flight. In the first, you can see the speeds at which the plane stalled. (You can click on the graphs to see them larger.)

This second graph shows vertical speed (VSI) and altitude. You can see how far the plane sank through the air and how fast it was descending during each stall. You can also see how fast it was ascending as I climbed back to 8500 feet for each successive test.

After landing, the plane was backfiring badly and trying to quit running as I taxied to the fuel pump. A quick check by my friendly local A&P revealed the cause. The intake manifold on cylinder #2 has come loose.

I have new O-rings and gaskets to do both intake manifolds on this side of the engine. I will be checking the torque on the bolts on the other side.