Since we had a rare sunny day up here in  Seattle, I went up flying for
an hour after going through the mode 3, 6, then autotune and then a
little touch up in mode 9, on the ground. It was running  pretty smooth,
but still does not like full throttle- maybe it's still a bit lean up
there, but I'm thinking that maybe the Hushpower is too restrictive- I'm
flying on  60% throttle, tuning with the mixture knob and the EGT is
running around 1700, RPM is ~5000, MP- Damn, forgot to note- maybe 17"?.
Funny thing, the coolant and oil is down around 110 f at these settings.
Definitely need to block some of the cooling air. I don't know if the
Dynon airspeed needs calibration, I did not have my GPS today, but was
only getting about 110 MPH at that throttle setting. I did get one thing
accomplished- I calibrated my AOA on the Dynon.

I'm starting to think about making my own very simple, robust muffler
out of 321- pretty much a straight 2" tube within a 4" tube, with some
holes and a few very firmly welded baffles. I'll try to get   a drawing
out and see what everyone thinks about it.


At least no one called the tower to report an aircraft in distress this
time.

Brian Trubee

I doubt the muffler is the problem. Unless of course it has already
failed
internally. You can look inside with a Home Depot or Harbor Frieght
bore scope.

What is your fuel pressure again?
What size fuel line are you using? It should be AN dash 6.
How many gallons an hour are you burning?

How are you with electronics Brian?
A data acq system would go along way to take out the mystery.

My plate is over flowing from here to the end of April but
after that I will be able to help.

Paul Lamar


My fuel pressure is 37-39 psi, fuel lines are AN-6, and I was burning up
to 10 GPH, and that was at a reduced throttle setting of less than 60%.

Next nice day I'll go up and get more data recorded.

Brian Trubee

It is a big mystery why that is not working. I am really exploring
the outer limits here. What size wire are you using for the injectors?

With a injector pulse width monitoring system we could check to be
sure an increase in fuel programmed into the computer actually results
in an increase in fuel injected.

Here is one way to do that. You need a CAS simulator. What that does is tell
Tracy's computer the engine is running when it is not really running.

The other thing that is handy but not essential is a hand vacuum
pump you can buy in the auto parts store. This can tell the pressure
sensors in Tracy's computer they are getting signals from the
manifold pressure when they are not.

Here are a few jpgs on the subject.
The 555 oscillator simulates the engine running and is connected
to Tracy's CAS pin.

This is a very simple circuits and the parts
can be bought at any radio shack. Hire an electronic nerd high school
student to build it for you. Put a help wanted add on the HS bulletin
board.

This company sells all sorts of small low cost kits.
http://www.jaycar.com.au/kits.asp

If you look long enough you might find a 555 Osc
or AKA function generator.
http://www.web-tronics.com/kit-23.html
http://www.amazon.com/Function-Generator-Kit/dp/B0017Y486K
http://www.fishersci.com/
http://www.elenco.com/



Here are a couple of useful magazines.
http://www.nutsvolts.com/ from the US
http://www.epemag3.com/ from the UK

Remove the injector from it's holder and let it squirt into a
glass measuring cup.

Paul Lamar


Is the 10 gph fuel flow based on Tracy's computer calculation from injector pulse width?  Or independent flow meter?  Or tank measurement?  Can you verify that fuel pressure is being maintained while at high power (in flight)?
If the fuel pressure is falling off, the pulse width based fuel flow will be off.

The low coolant temp might be an indication of very low fuel flow..

What takeoff mp are you running?  Will the engine run well at full throttle on the ground?

I gather the runtime problem happens when rpm rises?  Are you sure it's a fuel problem?

Does the EGT change significantly when going from running well to not running well?  The engine should run ok quite lean.  The EGT should be dropping a lot if it's going lean.

Intake manifold flow dynamics?  Organ pipe tuning?  Is fuel getting blown out of the intake?

Could it be SAG?


Do you have a camera you could mount in the cockpit to document what's going on, when?


Regards,

Matt-