The big day for the test flight of my “new 2012 model” Colt finally arrived. The test flight was a short one. We had a few gremlins to deal with, a couple of potential show stoppers, but we went anyway. Original plan was to have me checked out – again – insurance you know, but when we discovered that we had some issues, we stayed over the airport looking for what else may be going on.
Actually, the flight started with what looked like problem with COMs. I attempted to request a taxi clearance, but could not hear myself. Michael, my check-ride instructor, had the same problem in the right seat. As it turned out, a reversed wiring in the overhead console caused the problem. When I keyed the mike switch Michael heard me, and when he keyed his, I heard him. This was a simple problem, we just switched our headset positions in the jacks in the overhead console and all was fine.
As we were proceeding to runway 25, we had an oncoming aircraft in our path. We gave him a blink with taxi lights, letting him know that he can go ahead. That is the time when we noticed that as soon as we switched the lights on, the fuel tank indicators went to zero fuel. We tried other lights, and noticed that the strobes would also affect the fuel gages by lowering their reading a bit. By the way, the fuel gages may not be reading correctly and may need some adjustment. They are showing less fuel than there actually is. I am not sure if there is a way to adjust this on the gage. I will have to check on this, but if not, I can always cheat. Since resistive floats/probes in the tanks feed the gages, I can always add external adjustable resistor pots in series or parallel for the fine-tuning.
On the run-up, we noticed that the magneto check would not result in a change in rpm. We then turn the switch to off position, but the engine was happy to go on. The engine was running just fine, and the engine running parameters were all OK; however, to be on the safe side we decided to stay over the field instead of going for the check-ride. We leaned out a bit; the barometric pressure was 30.28 inches, which was easy procedure with the engine analyzer. The fuel flow works like a charm as well, 5.5 g/hr fuel flow at about 1700 rpm. With all the engine gages in green, we requested departure clearance. On the roll out, we noticed that the airspeed indicator went to 60 mph and stayed there. From there on our GPS became our reference speed indicator, giving us at least the ground speed reading.
With the tower’s blessing we climbed to 1900 over the field looking for other potential anomalies. It seemed that we got them all on the ground. Since we installed the vortex generators on the plane, we were interested to see the stall performance. With the airspeed indicator not working, we would not be able to tell the exact speed, but we would be able to feel the effect. The plane was always gentle in the stall, but with the vortex generators, it will simply go nose high, and then it would just settle in about 500 feet per minute descent – no drama. It sits there just coming down slower than a parachute. I actually checked this, because I was interested to compare the data. Depending on a canopy size, and the weight of the skydiver, parachutes are descending at the rate of 600 to 900 feet per minute. There was no tendency of a wing drop either. One could hold the yoke to his chest, and come down like in an elevator.
Another noticeable behavior, and this is to be credited to the previous owner who did the tweaking when he installed the new lifetime struts, was how well the plane behaves when trimmed out. We trimmed it out to a slow flight, 70 knots GPS indicated, to see a fuel flow of 3.7 gal/hr. I could just leave the controls alone, and the plane would fly like on an autopilot. When it was time to get back, we did the navy style, wide, 180-degree, turn approach. We trimmed the aircraft to what felt like the right approach speed, and took our hands off the controls. The plane stayed in the gentle turn until we had to level off to enter the final. Once lined up with the runway, we guessed the speed since we did not have the airspeed indicator working, and very likely we came in a bit faster than would be needed, but to a perfectly uneventful landing.
Overall, it was a good flight. One should expect some stuff not working right after all those changes we made. The unexpected would be the switch and the airspeed instrument. I took the plane back to the shop. Sham switched the COM plugs to their correct positions, the switch is working fine now as well, but the airspeed indicator is a toast. It seems that it sprang an air leak somewhere. It is an old instrument, I suspect the original equipment, and we had it in and out so many times, that we may have helped it a bit. The fuel level indicators will likely need shielded wires, or some wire re-routing, but that is not a big deal.
The Colt really is a sweet plane to fly. I thing Mr Piper had it right. It really could have made a nice trainer. Too bad, it never made it as such in larger numbers. In the mean time, and as a temporary fix, we installed another airspeed indicator, so we have a flying aircraft until the new instrument shows up. This will likely take a few weeks, since the supplier has to do the custom markings first.