Dave Nadler wrote on 8/25/2017 7:29 AM:
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...

Fortunately for Schleicher self-launchers, the "plummet mode" Dave describes does
not exist. Glide ratio for my ASH 26 E is about 20:1 in the pattern with the pylon
up and gear down. It feels like I'm flying Blanik - nothing to worry about, and
the practical effect of landing with the pylon up means I use somewhat less
spoiler than with the mast retracted. Gliders with the "engine on a stick", like
PIK 20E, are strongly affected when the pylon is up.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf