I got to test fly Tanker 60 today.Among other things,we needed to run in some new cylinders on all of the engines.Our latest instructions from the overhaul shop is to run for an hour at a fairly high power setting and try not to touch anything during the run in period.About the best power setting that uses enough power and doesn't burn an astronomical amount of fuel is 150 BMEP and 2200 RPM.Even at that,we're running around at 200 kts indicated airspeed and showing 800 pounds per hour (per engine) on the fuel flows.
About 15 minutes into the run in,#3 started a slight BMEP fluctuation and needed a bit more manifold pressure to maintain 150 BMEP that had taken before the fluctuation.A quick check of the ignition analyzer showed a double shorted seconday on #10 cylinder,This means that both spark plugs in that cylinder had quit firing.As #10 is the bottom cylinder,fouled plugs were a strong possibility,however,it could also be a sign of something rattling around inside the cylinder that had peaned both plugs.
So.we shut down #3 as a precaution and completed the run in.That brought the speed down to 190 kts indicated and I got to make my first DC-7 landing of the year on 3 engines (which happens on at least every other first flight of the year).Anyway,I took a few pictures.
You can see the #3 engine indications at zero in these two pictures
Here's Tanker 60 in front of the hangar.Pete Marshall is doing some trouble shooting.It turned out to be a bad ignition component,probably the coil.At any rate,there was no damage to the engine.
