Some Progress and Old Problems

[ksatter26]

Progress: Both flaperons covered in Sky Blue Oratex. I suggest that the 1st time Oratex user start with a flaperon as there are no complex curves to cover. The only difficulties I had with the flaperon process was handling the length alone. I did add Oratex doublers over the hinge slots.

My roll of FIXING tape arrived and it works really well. It seals against the Oratex and itself well; peels away cleanly leaving a nice straight demarcation line between the glue and the fabric. I'll probably order at least one more roll for use on the wings, and tail-feathers.

Problems: The old Polini no spark problem is back. I re-installed the engine that I got back from London Ivey in Tampa. It was purring as advertised in the video that London sent me. I held off a few weeks re-installing the engine as I completed covering the fuselage/air-frame with Oratex. Once I remounted the engine I attempted a startup and got a really weak turnover of the starter motor. I pulled the plug and verified that I had a spark. I had been informed that the starter motor likes a nice high amperage and above 13vdc. My battery was at 12.7vdc so I replaced it with a 13.3vdc battery and tried again. The crank was somewhat stronger, but no startup and after 3-4 tries, the new battery was down to 12.5vdc. while the batteries were on my charger, I moved my grounding wires from under a cyinder head bolt to the aluminum CDI mount where all of the original grounding had been done. This was at the suggestion of London becuse he indicated that the cylinder head bolts need to be torqued down pretty tight .

I replaced the battery and tried again with the new groundings. No joy. I once again pulled the plug ... no spark. I replaced the plug with a new one, also no spark. I took the kill switch out of the circuit, No spark. I isolated the electricals such that all I had was the motorcycle push button starter switch connected ... No spark.

Truly frustrated, I again removed ALL of the grounds and connected to a small terminal block with one wired connection to the original grounding location on the aluminum CDI bracket bolted directly to the engine. Still no joy ... no spark.

I have only one other possibility to test today. The possibility that the aluminum CDI mount bracket is not providing a sufficient grounding contact. I will check the continuity today.

My Polini has been a nightmare.

[LA F2 Flyer]

If you are grounding to aluminum it definitely won't work. If you recall exactly how it was sent by London return it to that state and go from there.

I have heard that the starters for the 303 can be suspect so also try pull starting. Sometimes there is not enough juice for both.

[Badland-F5 Pilot]

I don't know about the Pollini, but I've worked with electricity and electronics for 40+ years. There have been plenty of time when the media used (aluminum) caused issues. Copper Copper Copper is the only way to go, and use a larger gauge wire (smaller number) than recommend. Typically the recommended gauge is really more of bare minimum. Solder all crimp connectors. Crimp connectors are typically aluminum and have a tendency to corrode. This isn't to say they don't work, most of the time, but "most of the time" is not worth my life. Of course you aren't having a corrosion issue now. Just saying soldering crimp connectors is not a bad practice. Back to the issue though, aluminum bad, copper good. Just my two cents.

[ksatter26]

The CDI mount bracket appears to be aluminum. Also, on the backside a heat-sink-like component (also appearing to be aluminum) with built-in connectors is bolted to the bracket. As delivered, grounding wires are connected to both the bracket and the heat-sink.

I do have a concern about the starter motor draining battery voltage so rapidly. I start with the battery at 13vdc and after 3 or so starter tries, the voltage is down to 12.7 or so. I have an additional Universal motorcycle battery rated at 4 AH. I also tried attaching both batteries (in parallel) with the same results.

As I've reported in my Build Log, this engine has been nothing but problems since delivery.

[Badland-F5 Pilot]

Being that electrical resistance increases over path length means that the connections at the CDI shouldn't be an issue. Do you have a ground wire from the CDI bracket directly to the battery or are you using the frame?

The starter motor draw is a valid concern. The drop in voltage should only show during cranking. Actually dropping that much and remaining low is certainly something to look at. This, especially since you tested by connected two batteries and still have the same issue.

What confuses me is that all seemed to be good on your engine stand, and went south upon install on the plane - is this correct?

Maybe time to back up to that point, unmount and try again on the engine stand?

[LA F2 Flyer]

To add to Todd's point, if the engine ran fine on the stand the issue has to be something you added during the install. These engines are meant to be a "closed circuit", since they are usually affixed to someone's back (and I can't imagine that "someone" being used as a ground.

I think you should install it as such; just copy what was on the engine stand without adding any extra wiring, ground or otherwise.