What Lynn said. Most newer cars cut the fuel in that condition and it DOES eliminate the miss because the engine isn't even running. We don't want to go there because of the lack of lubrication.
But most of us pilots were taught to make all throttle changes smoothly and gradually anyway. Slamming the throttle closed is considered bad form in an airplane. We do need to deal with the situation where we are going downhill at the end of a flight and the engine can be windmilling for significant periods of time. We are in a special situation for two reasons. First is the lack of apex seal lubrication Lynn mentioned but also the limitation of the gear drive. The nylon snubber in the drive is not designed to absorb long term reverse thrust when the engine windmills. I'm always conscious of maximizing the energy of altitude and descend with a small amount of power rather than the drag of a windmilling prop. This maximizes fuel economy, keeps the apex seals happy and keeps the torque going in the right direction in the gear drive. The number will be different for different airplanes but for RVs a descent rate of around 300 fpm at 130 - 140 mph IAS works out well. Plan ahead and watch the Vnav numbers on your GPS for when it's time to start down. If you have an autopilot, program it for the appropriate numbers. We don't fly 747s so throttle control is still up to you.
Tracy
Sent from my iPad
Closed throttle at high revs makes a good fuel burn (idle mixture)
unlikely. The effective compression ratio drops to near zero due to poor
cylinder filling.
Fuel molecules are very far apart. The stock Renesis maps up to 44
degree of advance in this situation. The mixture burns very slowly requiring the
added advance (more time to burn). Popping and clicking is still burning mixture
lighting charges in the headers (turbo?) from chambers that didn't light at all.
(Misses).
In racing engines we didn't use the OMP and only premixed synthetic 2 cycle
oil. So I jetted the idle mix real rich to keep the lube going in high rev
closed throttle moments.
The sheets of fire out the tail pipe was a crowd pleaser as well as the
explosions on gear changes. It didn't count against our 105 Db sound
limit.
Lynn E. Hanover
I had
the same issue. I cut the fuel and added a bunch of advance for
high-rev/low-MP operations. Cleaned it right
up.
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