In a message dated 1/21/2008 9:06:34 A.M. Central Standard Time,
walter@advancedpilot.com writes:
Nice summary. In addition, if he is using the air pressure under
the cowl to push air into the injector (through the screen on the NA
injector), the addition of RAM air to the induction increases the MP to the
point that he no longer might have enough upper deck cowl pressure
differential to result in anything more than a pencil stream in the FF.
That alone--even with excellent F:A ratios could result in rough running
as the fuel would be more liquid than vapor. That's what I understood
his message to be about. If my interpretation were correct, then he's
right about adding upper deck pressure to the injectors to increase the
differential pressure between MP and cowl pressure into the
injector.
Walter,
Thanks. What you makes sense. It is another reason why
running an evenly distributed air supply to injectors at
or above deck pressure is beneficial by independently controlling one or two
combustion event variables. My point was not clear if one doesn't realize
that each change may have unintended consequences and that any given change may
not cause universal improvement without, perhaps, having to
make others. Once one starts on the path of dickering, the desired
result may prove to be a bit elusive. If one has a means of measuring
happiness, such as inter cylinder measures like FFs close at peak, leveling of
CHTs, EGT ranges and others, it is important to keep tabs of those to track the
results of even subtle changes.
The fact that my airworthiness certificate was issued in 1996 (late last
century) only meant that the experiments stopped being theoretical and
started being practical. At last, flight was providing
feedback. I am almost through with dickering.
Scott