Thanks, Steve,
Tracy would have to enlighten me about a timing change. I haven’t
touched the timing from the factory settings. I will take a look at the
MAP though. What do you think could be causing the fluctuations? A leak?
This is at WOT. I only close the throttle if I am in the pattern to
land. I control the engine speed with the MT electric prop otherwise.
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Steven W. Boese
Sent: Thursday, September 06, 2012
11:17 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re:
Intermittent hiccup
If the end of a piece of copper tubing is
crushed in a drill chuck, you can make a constriction of whatever size you want
depending on how much the tube is crushed. The photo is of 1/8" od
tubing that was used to dampen under cowl pressure measurements for
cooling investigations by inserting it into the sensing tubing. The
constriction would be most effective if placed between the intake manifold and
the chamber (fuel filter).
It is hard to imagine that the change in MAP in
the range of 26.7 to 27.1 would in itself cause a hiccup unless a significant
mixture or timing change is associated with it. An examination of the
controller maps might shed some light on this.
The instances of sag that I have encountered
have not been hiccups but a sudden transition to new steady state condition of
reduced but smooth power. For me, recovery from sag did not happen
without some sort of operator intervention.
FWIW
RV6A, 1986 13B NA, RD1A, EC2
From: Rotary
motors in aircraft [flyrotary@lancaironline.net] on behalf of
Bill Bradburry [bbradburry@bellsouth.net]
Sent: Thursday, September 06, 2012
7:21 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re:
Intermittent hiccup
Do you think that I could have an intake
leak that is causing this fluctuation? This makes no sense to me. How
could it be fluctuating??
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bill Bradburry
Sent: Thursday, September 06, 2012
12:11 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re:
Intermittent hiccup
I noticed that the manifold pressure was
fluctuating between 26.7 and 27.1 during cruise today and I was getting some
hiccups.
Did you block both ends of the filter or
just one end? I don’t think I have a drill bit smaller than
1/16. What did you use to drill the holes?
Bill B