flyrotary@lancaironline.net Mailing List Archive

Ed, Did I understand that you have to have the “snubber” modification in order to get the injector simulation mode? I have not had this mod. My instructions are at the hangar, but I thought the “snubber” mod was the one that made the simulation mode possible.???

The engine runs fine with either primary or secondary injectors disabled. Also with leading or trailing coils disabled. My fuel pressure is 39-40 lbs when the engine is not running and 35-36 lbs when it is running. Turning on the secondary pump raises these numbers by 2-3 lbs. I can hear fuel being returned to the tank when the engine is not running….when it is running I can’t hear anything!! J

Bill B

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Tuesday, October 23, 2007 8:31 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Fuel delivery at WOT

Bill, I do not have a Renesis but may have some things for you to check.

With the older 13B with the 460 cc/min injectors, you could get full power to over 6000 rpm on just the primaries along. The Renesis I understand has smaller primary injectors - like 250 cc/min. I strongly suspect they would NOT support full power past 6000 rpm perhaps even less. So I suspect one of the following:

1. Secondary injectors not firing

2. EC2 is not staging to bring on the secondary injectors

Your fuel flow does not appear to be the problem because when you hit the cold start switch you got more fuel - but you didn't say how long you ran it with the coldstart on - a few seconds or several minutes? If several minutes, I would say your fuel flow system is probably not the culprit.

The first thing I would check is to make certain all four injectors are firing. You can do this by selecting Mode 1 and (after making absolutely certain your fuel pumps are all OFF) hit the program button. This should start the injector simulation mode - all 4 injectors clicking away like mad. Using a small wooden/metal rod tube to hold close to your ear place the other end on each injector - you should hear all four clicking. If the secondary injectors are not clicking then you can start your trouble shooting.

The injectors could all be working, but for some reason the EC2 is not staging - don't know what would cause this, but if the staging manifold pressure were accidentally set to much higher than Tracy recommends, then you could be running out of fuel from the primaries before the secondary kick in.

Even if the secondary were not working, by turning on the cold start you would have doubled the pulse to the primaries thereby essentially doubling your fuel amount injected.

Lastly you could have a fuel flow restriction some place in your system.

Hope this helps.

----- Original Message -----

From: Bill Bradburry

To: Rotary motors in aircraft

Sent: Tuesday, October 23, 2007 6:34 PM

Subject: [FlyRotary] Fuel delivery at WOT

I have been concerned that I am not getting the static rpm that others are getting with similar props. I have the stock Renesis with the Performance Props 76 X 88. I seem to be limited to about 4200 rpm. I hit 4800 once the other day, but did not know what might have caused the change. I just finished the install of the pressure overflow bottle per Lynn’s msg of a while back and was running the engine up to try and eliminate any air that might still be in the engine. I noticed that when the rpm reached 4200 or so, I still had about an inch of throttle left. After pondering that for a couple of minutes, I pushed the throttle to the wall, the engine started to run rough, and I reached over and flipped the cold start switch on….

Mein Cod!!!

It immediately hit 5350!

Apparently I am not getting enough fuel flow to support high rpm. I have not done the self tuning at high rpm yet, but I would not expect that the fuel flow would be so low as to limit the rpm.

What suggestions do you have? My ability to self tune has been limited due to cooling issues…especially at WOT!

Lynn, it is too early to be sure yet, but your idea for the pressure bottle looks like it is going to help the cooling a lot. It may not be the complete solution, but it seems to be a step in the right direction. Thanks!

Bill B