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This discussion is timely, given that I'm in the midst of tuning my engine. I was getting the bogging and then surging right at the point that the secondaries were turning on, and I also seemed to get good results by richening it up for thefirst 3 bins where the secondaries are cutting in. This is on the ground, of course. I think that I will see some need for tuning in the high RPM/ low MP mapping table when I am in the air descending. Or maybe not, as I recall the airplane was making a siren song to me that it was running smoothly as I was descending to land, calling for me to go around because it was now smoothing out.
As it turns out, my spark timing is right on the money.
Also, my primaries are 28 lb, and the secondaries are 40 lb injectors, so my staging point is at map station 89~90 right now. I think that might be a little high.
Here's another unrelated issue- I have an RV-4, with the fuel being taken out of and returned only to the right tank. I have an AN-6 line feeding a facet pump located just aft of the batteries, and it transfers fuel to my righ hand tank when I want to transfer the fuel.Both tanks are vented separately. Here's the problem: I started out with 12. 5 gallons in the right tank, and 6.5 in the left. After running the engine on the ground for 1 hour, I ended up with 12.7 gallons in the right and 1.7 in the left, without ever having run the transfer pump. The only thing I can think of having happened is that the plane was parked slightly- 1 degree or so-right wing down. The facet pump I believe has a one way valve which would allow fuel to flow downhill to the right tank. That's my theory, can anyone else offer a theory as to why the fuel is self transfering?
Brian Trubee
RV-4
-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sat, Nov 6, 2010 3:46 pm
Subject: [FlyRotary] Re: Staging Adjustment in EC2 since 2006
Ok, thanks for clarifying, Tracy.
One other point that Bill and I bounced back and forth - can this Mode 6 adjustment be used to lean and/or enrich the above staging mixture? In other words, can you do both or can you only lean the above staging setting?
Ed
Sent: Saturday, November 06, 2010 6:38 PM
Subject: [FlyRotary] Re: Staging Adjustment in EC2 since 2006
"Here is a comment from Tracy back in April”
Also note that Mode 6 will have NO effect on the mixture if you are below the staging point (which you no doubt were at a MP of 14") It only affects the mixture above the staging point, ie, when the SECONDARIES are on."
Wow, it sure is hard to describe this stuff. Actually I think Bill and Ed are both correct but here is the factor that may help explain things. It IS true that the Mode 6 adjustment you make will make no REAL TIME change if you are below the staging point. But it WILL change the mixture above the stage point EVEN IF you make it below the stage point. You will just not see it until you advance the throttle above the stage point. ie, You can make the adjustment above or below. Which side to do it on is just a personal choice. I do it on the low side then check it above, then repeat until I'm happy. Once you wrap your head around this it only takes less than 2 minutes to do it.
I'm looking at Steve's very interesting data on injector flow rates to see if I can incorporate it in the EC2/3 algorithms and minimize the amount of Mode 6 and MAP table tweaking needed.
Tracy
On Sat, Nov 6, 2010 at 9:38 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
Pertaining to Steve's data and analysis and Tracy's comments about Mode 6 of the EC.
I went back and read up on the Ec2 modes and found this statement which I had apparently not paid sufficient attention to, but in light of Steve's data and findings, thought it might be pertinent to the discussions. From the EC2 instruction Manual:
01-07-06 update
.
Because the rotary has two injectors per rotor and they are staged (see Mode 7 for details on staging), it is possible that the mixture
might be miss-matched differently when staged or not staged. You may have to match the EGTs once when the engine is staged
(low power) and again when not staged (high power).
So it appears that the EC2 has had the capability to adjust the different in flow rates across the staging event since at least 2006. But, perhaps like many others, I was not certain what conditions would signify this needed adjusting (until Steve's data and analysis) and therefore never attempted any adjustment (my dumb!) - my philosophy being if it is working well and you don't have a clue as to what/why you are adjusting something - then DON'T! {:>)
The only "problem" (actually more of an irritant than a problem) I have ever encountered using the EC2 was the staging "bog" I would encounter while operating on the ground which I finally eliminated. What I did was to enrich the fuel MAP in the 3-4 bins in the High MAP region that the engine point jumped to after staging. This did solve my staging bob - but, after reading the EC2 instructions again, I can see that if I probably should have used Mode 6 to accomplish this as my adjustment was just for 3-4 bins and not all bins.
Once again Tracy has addressed the need in the Ec2/3 - but, I just failed to understand the function (and conditions) it might have addressed. Now that Steve has clearly shown there is a high probability that adjusting the staging flow rate will result in more accurate fuel totalizer values and other fuel factors, I can now see a reason to use mode 6.
Thanks, guys - discussions on this list is generally always educational and helpful
Ed
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