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

Bill,

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

Steve Boese

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