Brief Description: Bring project log up to date after hard drive cras
Fuselelage is covered and painted and back in the hangar to start hanging landing gear and equipment. Poly-Fiber system is well documented and straightforward to use.
Hirth 3203 Engine: the exhaust manifold broke off during a 5500 RPM run in the break-in sequence. The fracture was just inside (engine side) of the weld between the wye portion of the manifold and the straight tube which slips into the ninety degree elbow hosting the ball joint. The failure was exactly the same as experienced on the 2702 on New Years Day. Exact same failure mode and pattern. This one was replaced under warranty with the suggestion that I change from the IvoProp to some other prop to reduce vibration. The motor was purchased with the distributor's Challenger engine mount and exhaust, which was all pre-welded and ready to bolt up. The rig was assembled exactly according to documentation.
The new manifold is on the engine and has cycled through maybe a half dozen runs up to full RPM and a total time of about 2 additional hours on it. If this one cracks, I will re-weld it with reinforcing steel around the apparently weak area of the manifold. The factory MIG welding on the manifold is good quality.
Finally got some good full-throttle runs on the motor after replacing the exhaust manifold. Got the prop dialed in to 6500 RPM at WOT. There was a bit of stumble at WOT, acting very much like the motor was getting too rich. Adjusted the fuel injection timing just slightly and cleared that problem. CHT and EGT are dead on the documented values. Voltages are steady at 14.7 VDC above about 3500 RPM. Max charge current is 18A on restart then settles to the expected 5A when the battery has recharged. Fuel injection pressure is steady at 43PSI.
The motor has 14.0 hours on it and has completed its break-in cycle. It is ready to hang on the fuselage. 17-gallon aluminum fuel tank from Greg Klemp in Neshkoro, WI has been modified to accept a low-fuel-level float valve switch and a larger return line fitting from the fuel
