Stephan's Sonex #1627 Builder's Log

UL Power UL260i

The UL Power UL260i appears to be a solid engine. It is a purpose-built full FADEC engine developed in Belgium and capable of developing approx. 97 HP at 3300 RPM and 8:1 standard compression. The UL260is develops 107HP at 3300RPM, but runs at 9:1 compression. Typical long term engine reliability is proportional to the compression ratio, where higher compression ratio decreases the MTBF.

There is currently no Firewall Forward (FWF) package available for th Sonex from UL Power, but the company indicates that the Jabiru 2200 engine mount is compatible with the UL260i engine. There is a weight difference between the Jabiru 2200 and the UL Power 260i, so I will need to investigate whether the Jabiru engine mount is dimensioned to handle the increased weight of the UL Power engine.

There is currently no Sonex flying with the UL Power, although the website indicates that at least one builder is developing his own FWF package. I reached out to the North American UL Power distributor, Robert Helms, who indicated that Richard Kaczmarek is the builder. I have not yet contacted Richard for additional details.

A review of the NTSB accident database for the UL Power engines revealed a single entry for a non-fatal accident with a Sonex on February 6, 2009. I turns out that this has been the only Sonex flying with a UL Power engine. I contacted the builder, John Davis, to determine his overall impression of the engine and to provide additional background to the NTSB accident report. The accident report indicated an engine failure as a result of the electronic control unit (ECU) being mounted in the engine compartment instead of on the cockpit side of the firewall. The ECU had apparently overheated and failed.

John indicated that he knew that the ECU had to be mounted in the cockpit, but that the supplied ECU cabling wasn't long enough to allow it to be mounted there. I confirmed with Robert Helms that you can now get the ECU cable to size. John ended up selling the engine back to the US distributor, as he was never able to reproduce the exact issue. He also commented that he UL Power never investigated the engine operation after the crash or seem interested to determine a root cause of the failure.