flyrotary@lancaironline.net Mailing List Archive

Yes, I meant primaries. I do have an air tight box to go over the end - for use with the turbo. I had just taken it off to save some weight. It will be easy to put back on.

I had tried to set the injector staging to 28" (pressed the button on mode 7 while running at 28" MAP). I even went for a short test flight and couldn't smell any fuel. But 10 min. into the flight home we realized that we were going to be smelling fuel.

This weekend I will just unplug the power from the secondary injectors, then work with the transition point and the mixture map, and I will re-install the air-box.

Dave Leonard

Don't have a solution short of building a new intake or a really tight airbox with longer air feed path to throttle body. Just one more reason I don’t like injectors on the far end of intake.

I can confirm that most people vastly underestimate the violent activity (including reverse airflow) in an intake system.

Last point: It is not possible to program the EC2 to run only on the secondaries with the staging level . Did you really mean primaries? You could accomplish what you wanted by disabling the unwanted injectors if you installed the disable switches.

Tracy

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

From: DaveLeonard

To: Rotary motors in aircraft

Sent: Thursday, October 28, 2004 12:40 AM

Subject: [FlyRotary] There I was, half way to Vegas...

So as you know I have converted to a normally aspirated state. I went flying to vegas this weekend, and actually won $300 net even after my wife lost $100.

The engine ran as well as coulld be expected considering my sea level WOT MAP is only 28". Max n.a. static is 46-4700 RPM. Plenty enough to take off well over Van's recomended gross and fly at 130 KTAS (using only 8 gal/hr). Better than a typical cessna - but less tan I had with the turbo. Anyway,

The point of this e-mail is to discuss injector backflow... I have always had a problem with a faint fuel smell in the cocktpit. As part of the n.a. conversion I removed the plenum over the intake (see pic.). Every flight since removing that plenum has included a rather strong smell of fuel coming in theough the passenger air vent. This smell is only evident after take off. It turns out that my TWM secondaries, mounted on a downhill part of the intakes, freely leak fuel down and out of the bellmouths even during WOT operations. This leaked fuel then seeps out the cracks in my cowl and goes into the passenger air vent. It also loostly covers everything on that side of the engine, and the side of the fues around the pax air intake with 2-stroke oil. This was enouth to make me uncomfortable. The wife, who is still reeling from the emergency landing after the turbo broke, now states that she will only fly cessnas from now on - due to the very disconcerting smell of fuel the whole trip - and I can't blamer her.

While in vegas I tried to program the 'B' computer to use the secondarys only above 27" MAP but I guess the adjustment did not take because we still had the same condition on return. I have checked and re-checked the fuel system far any evidence of a leak. It is coming out the back end of the intake for sure.

Something to think about if you are installing the TWM injectors near the air inlet end.

Dave Leonard