On Wednesday, September 18, 2019 at 3:16:37 PM UTC-7, Eric Greenwell wrote:
Dave Nadler wrote on 9/18/2019 7:43 AM:
On Wednesday, September 18, 2019 at 9:07:32 AM UTC-4, Eric Greenwell wrote:
...is many motorgliders do not "plummet" or become less controllable
because the mast is up

And, many DO plummet, with reduced control authority.
It is highly dependent on what kind of glider!
Don't assume...

That's why I recommend owners try at least one airport landing with the mast up,
and engine stopped, so they know what to expect if it happens to them. The 26E,
with the gear out and mast up, reminds me of landing a Blanik.

I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

--
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
,

This is true. I fly a DG800 and with the mask out the sink rate is 4-5 knots, so my glide ratio is roughly 4-5 less. Air starts are typically on down wind to a know good field with in a 10:1 glide. If I am over uncharted territory, I will initiate the restart at a much higher altitude, even this adds extra risk if the engine won't start and I can not retract. The manual clearly states that landing with the mask out can easily lead to a hard landing, especially if any spoilers are deployed, they recommend no spoilers and extra airspeed needed to overcome the added sink rate on touch down. If you were about to land in one of the most difficult fields in your career, why would you choose to make it extra complicated with a engine mask out.. That is if you were not still being wishful it would miraculously start working. I feel this is a critical moment every MG pilot will find themselves one day. So over unlandable or very difficult terrain the plan of action to relight needs to happen at a much higher altitude that will allow retracting if things don't work. With the mask out most gliders performance degrades and requires extra airspeed to reliably reduce the extra sink rate on touch down. We all make mistakes and learn from them. A glider with a mask out in a very difficult outlanding is not good planning, especially if the mask system is working and the engine is not. Those that don't fly a MG think we have some advantage, when indeed we need to terminate our flight as a glider at a higher altitude. If you want to roll the dice and try to restart from a low altitude, if it works great which most of the time it would, but when it does not you are disadvantaged and add plenty of risk. Of my friends who fly a similar glider, one did the right thing in a difficult landing in a known good short field deep in the woods, rather than try a restart he landed. The other landing short with his mask out hanging in the trees on another day.

BG