Met Chris at the airport today for a short little session.. couple items on the punch list...

Chris had picked up a replacement second fuel filter (fine element in a bowl) to be placed between the pumps and the injectors. The original i had bought, I had cross threaded at some point and the fitting/base was toast. We still had a coarse screen upstream of the pumps to catch large trash, but wanted to keep smaller stuff from plugging the fuel injectors

We placed the new filter on there, removed the checkvalve I had used as a male-male union/placeholder. In the process I took a small bath in 89 octane mogas, before we realized that the line was below the sump, and siphoning, and we sealed the cutoff.. Ooops. No smoking please!

While i was there, I also had come to the realization over time that I had set the fuel pressure regulator based on memory to a value of 44-45 psi. After reviewing the manuals that came with the upgraded EC2, I realized the correct value is in the 35-36 psi  range. This was resulting in a significant over-rich condition.. 25-35% excess fuel injected based on the default map of the EC2 (fuel flow is a function of pressure and opening time).

Keep in mind that previously we were also over-rich because of a manifold pressure sensor leak that caused the EC2 to think it was at wide open throttle. We were literally pouring fuel into the engine, no wonder flames shot out the tail pipe.

Chris also removed and re-installed the IVO prop, this time placing some limiting washers into the assembly that were called out,( but never actually placed in there by me, and not communicated about this). We then flattened the pitch on the blades to a finer setting because on Chris's last run he stated the engine appeared to be bogging down when he opened the throttle.

This time, starting was EASY. The BEST START we've had yet, and one of the best runs we've had yet. Fuel pump on, mixture at midpoint, mode 0, no prime, CONTACT. 3-4 seconds crank and we were running. When we leaned from midpoint the engine began to bog, and would falter and stumble past the 9 o'clock position on the knob. We warmed it up, with good temp readings on oil and coolant (95 degrees prior to start, good climb in temp while running). Killed it. Did a hot start with good re-start.

Things run rough on B side now, not really amenable to leaning.. it stumbles. The programming hasnt changed, so its either a function of not having a temp sensor, or we still have a wiring gremlin with something that is only active on B side (coil disable?, bad sensors on the B side of the unit)

We intentionally ran the unit long and hard enough to reach 210 degrees water temp, saw the blinking at 211 so we know that the over temp alarm works. We then chose to do a shutdown and hot start again. This time we didnt get the desired start. We really didnt try too many variables at that point, due to time. Next time we will try running the pump for a full minute to cool the fuel rail prior to attempting a hot start. There is a heat shield but there are exhaust components less than a 1/4" away from the fuel rail's integral heat shield. That will be changed by the time we fly.

On a side note.. I have determined that when I was building I led myself to believe that the oil pan did not require a gasket, and that sealant was adequate. In my installation this has proven to be completely and utterly false. The gaskets are on order, and we will be lifting the engine up a few inches to drop the pan, scrape sealant and re-install with gaskets on both sides of the sandwich plate. The leaks appear to be coming from the upper side of the sandwich mount/engine interface, where oil spills over during its return to the pan.

I may talk to Chris about a second oil temp sensor between the engine and the first cooler so we can examine the temp delta across our cooling system. Likewise may tap a probe into the tank of the radiator to read the colder coolant temp exiting the radiator to examine that delta as well. At this point in time we have NO airflow over our rads other than what natural convection and wind generate. We are pondering a small fan covering one portion of our rad to assist with this, and I am also interested in using a spray bottle system as well if needed, to spray an evaporative coolant on the radiator if needed for ground ops or high performance climb.

Keep in mind we have not run our ducts yet. The radiator in use was purposely selected by me, a sirocco style crossover design. The easiest explanation is that there are two radiators stacked one on top of each other, and the water flow enters in our case at a top right half tank, goes to the left, drops down in the left side tank, then flows to the right and exits through a lower right half tank, in a U shaped or C shaped flow pattern. I did this with the idea of using an aux fan being on my mind from the very beginning. John Slade had used a full sized fan that covered the whole radiator, and was actually obstructing flow at higher speeds, and was a hinderance to his performance. By using this radiator design, we can place a small fan that covers less than 1/4-1/6 of the surface area of the rad's frontal area, but provides cooling airflow to fins that contain 100% of the coolant flow. At lower power settings on the ground this should be more than adequate. At altitude and speed, the unobstructed remainder should be adequate, and if need be we can use the fan there as well, or leave it on 100% of the time.

Today was our best day yet with regards to engine starting and operation. Its all coming together one bit at a time.
1.4 hrs recorded engine time. Actual is estimated 2.0 or more.

Dave Staten
Velocity N-17010
Mazda Rotary 4 port, NA for now.

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