Relentless

[supercub]

Re: Relentless

Great job of handling the mayday. I heard the prop came off because of the sudden engine stoppage........however viewing that video and listening to a very rapid and high pitch whine, it seems the prop oversped and came apart, leading to the engine failure. Do they know exactly what did happen and in what order? Again, great job of flying.....looking forward to seeing you next year.
Brian

[wyhdah]

Re: Relentless

Had a good look at Relentless and recovered pieces this morning. Also took in Kevin's response to many questions (including a couple of my own).

Kevin and crew believe a line to the oil cooler failed first which caused a loss of oil pressure. The loss of oil pressure allowed the composite prop to go "flat" (low pitch angle/high RPM) resulting in an engine over speed (WAY over speed). Result of the over speed was the shedding of prop blades, disintegration of the accessory case, and what appears to be a connecting rod or two out the top rear of the crankcase. The propeller hub broke off cleanly between the blade attach area and attachment to the engine crankshaft flange. The engine also backfired in a big way blowing the induction system apart.

In Kevin's own words, "That happened in the first half-second."

A small oil fed fire erupted after landing which was quickly extinguished by the fire department. All notable damage is firewall forward. The engine did not leave the mount. There's damage to the upper cowl half likely caused by departing propeller parts.

A lot more was said but I've tried to stick to the technical side as there seemed to be a lot questions and speculation, but not much information.

Stevo's picture captures it visually, but the sound was something else. I would describe it as a loud, high pitched, attention getting "BRAAPPP!" ending with a distinct "POP", then silence. And Kevin was right, it happened in the first half second.

Kevin did a great job handling the emergency. It took skill and a huge dose of cool for the successful outcome.

I believe the cause has been stated.