Best Overall Motorglider available today?

wrote on 9/17/2020 8:23 AM:
On Thursday, September 17, 2020 at 8:48:10 AM UTC-4, Eric Greenwell wrote:
2G wrote on 9/16/2020 9:10 PM:
On Wednesday, September 16, 2020 at 5:56:25 PM UTC-7, Ramy wrote:
The Carat has relatively low performance according to a pilot I fly with often.
For me (cost constrain, strong tendency towards simple low maintenance, reliable, simple, safe and quick to operate with small risk of getting into trouble, minimal performance compromise, as close to pure glider as possible) the only solution I can think of is adding Self launching FES option to my glider.
I figured it would have got me home 80-90% of the times I landed out, and to a better landout place the rest of the time, have the potential of saving my butt if I make bad decisions again, and may allow me to fly when the tow plane is grounded, there is a long line or I want to fly from somewhere else, and would allow me to explore further than I would otherwise, and overall reduce my dependency on others.
Range is not a significant constrain, I rarely land out more than 100km from home.
Unless someone convinces me I am wrong, I will seriously consider adding an FES to my ASG29.

Ramy

Personally, I am not satisfied with the reliability and safety of the FES batteries and would not fly with them. The percentage of installations that have had fires is unacceptably high. Eventually, the glider community will acquire millions of hours of operational data to establish its reliability (or lack thereof).

Tom

What is the percentage of installations that have had fires? What would be an
acceptable percentage of installations with fires? And are the hours you mention
motor hours or airframe hours?


Airframe hours, years, charge cycles...

Anecdotally I got the impression that there have been more battery fires in FES gliders than fires in gliders with gasoline-fueled engines, at least in recent years, and the number of FES gliders is relatively small. Li-ion seems risky. Personally I hope better battery chemistry will be developed, that is both safer and has the needed energy density. LiFePO4 is safer, and its energy density is improving, some electric cars are switching to it. Other chemistries are in the pipeline.

Because there were significant changes in the FES batteries after the fires, I
think the current reliability should be estimated using the number of fires
post-updates. I'm not aware of any, but perhaps there are not enough
hours/flights/years on the revised batteries to have a good estimate.

--
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