On Friday, August 25, 2017 at 10:15:06 AM UTC-4, Dave Walsh wrote:
Dave N: Be interesting to know what on earth "plummet
mode" is in the Arcus M?

Plummet-mode is when engine is extended and not running.
Not exciting in Antares or FES, a bit more so with turbos.
Exciting in gas-powered pylon self-launchers (engine/radiator drag).
ArcusM is not too bad - about 500fpm.
Some motorgliders are more like 800fpm which definitely focuses one's attention.

Planning for plummet-mode is especially important for safety during:
- departure route
- powered flight between landable areas
- shut-down activities
These engines have a very high failure rate and its truly exciting to have
a failure on departure - you better have your response planned in advance.
Power-plant retraction is also failure-prone, so advance planning about
when to give up and restart or land is advisable...

Hope that's clear!
Best Regards, Dave