flyrotary@lancaironline.net Mailing List Archive

Hi Bill,

Here is my take for what its worth.

Your description (and flow values) sounds like you are encountering to what I refer to as "staging bog", in my case, during the staging event my air/fuel ratio indicator would disappear off the lean end of the scale and the engine would momentarily stumble. I ended up enriching those fuel bins (in my case bins 67-72) that my pointer jumps to immediately after staging - the bog disappeared. So in line with what the EC2 manual states and Steve's findings, it would appear that some enrichment may be needed.

Tracy indicated in his recent e mail that Mode 6 could be used to address the "flow rate" from below staging point to post staging point of operation. Now the description of this mode in the EC manual indicates it was apparently designed for those situation where folks used a different (larger flow rate) injector in the secondary positions. However, Tracy's suggestion to use it to compensate for a needed difference in flow rates (increase or decrease) across the staging point makes sense to me.

Its is suggested that you use your Air/Fuel Ratio indicator to determine which way to adjust using Mode 6. It sounds like in your case, you need to enrich the flow after staging rather than lessen it. So taking the opposite approach to the description in the Ec2 manual (which was adjusting the staging so it went leaner after staging), it would seem you would get below your staging point (so only the primary injectors are operating) and enrichen the mixture using mode 6 and using the Air/fuel ratio indication to see the results. Then advance your throttle so you go above the staging point - and see if that has improved the situation. If not enough, then drop back below staging point and again increase the mixture with the Program Mixture knob greater than 12:00 enriching the mixture and then take the engine back above the staging point.

I believe this is essentially what I accomplished (enrichen the flow) by manual adjusting (increasing) the MAP values in the bins my engine jumps to after staging.

The reason you don't get the bog dropping down ( in my opinion) is you are going from a leaner flow (above staging) to a richer flow below staging - therefore no bog. But, going from a richer flow to a leaner flow during staging causes you engine to "bog".

Others may have different suggestions.

Good Luck

From: Bill Bradburry

Sent: Saturday, November 06, 2010 10:32 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Staging Adjustment in EC2 since 2006

I have been working with staging for a couple of days and have my normal confusion.

I have the Renesis engine but I have changed the red primary and blue secondary injectors to all yellow injectors. This gives me roughly the same fuel flow capability when all four injectors are on, but a higher flow capability when only the primary are on as compared to the normal Renesis.

My staging point is set at 15 inches. I know that is lower than Tracy recommends, but it reduces the cooling requirements while I mess with it. I may change it later if I figure out what I am doing and get better (faster) at fixing the settings.

If I have the manifold pressure above the staging point and slowly lower it, it is a smooth transition and there is no indication that I can see or hear that the staging has changed. BUT!

If I have the pressure below 15 and slowly raise it, it seems to me that the engine is trying to make a decision as I go above 15, until I get to about 15.5, then it suddenly makes a different sound and jumps to 16.0-16.5. These bins are about 43 or 44 at 15 inches and it always jumps to 47 or 48. The map table levels in this area are close to the same.

I have not been able to determine if the change need is to lean or richen the mixture. If you read the study Steve did, it would seem that it needs to richen??

I tried a suggestion I read of Tracy’s…I checked the fuel flow just below the stage point, 2.7 gal/hr. then above the stage point.4.1 gal/hr. This caused me to conclude that I needed to lean it, so I lowered it back down below the stage point to get started trying it and Whups! The fuel flow was still at 4+gal/hr! I waited for it to lower but it didn’t???

I realize this sounds like I am rambling…..so what else is new!

Any insights would be welcome.

Bill B

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Saturday, November 06, 2010 9:38 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Staging Adjustment in EC2 since 2006

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

Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com