BG wrote on 4/11/2020 10:17 AM:
On Saturday, April 11, 2020 at 9:04:39 AM UTC-7, wrote:
On Saturday, April 11, 2020 at 4:51:34 PM UTC+1, Martin Gregorie wrote:
On Sat, 11 Apr 2020 08:10:55 -0700, Muttley wrote:


Like to confirm a real world experience I had some years back while visiting El Tiro. I was there with my DG 800b took real interest in an Antares 20e that was tied down. I beleive the advertised climb from sea level in still air is 9000 ft. Well, sitting next to the glider was a hefty Honda gas generator. I asked the owner some question about his experience so far. First thing he said was he was disappointed. They found once the ground temperatures were above 100F they need to keep it in the shade before launch. If they left it ouside the batteries would over heat at around 1000AGL. Guess it😁 was designed for cooler climates like in Germany. Next I asked him how long it took to recharge the batteries from the generator.. He basically said all night long and consumed 10 gallons of gas. I doubt there are airports that would allow you to tap into their grid. El Tiro was using solar panels. On sites like Truckee where you can camp on the airport, you would become very unpopular in a hurry have that much noise. I have never seen an Antares fly from there, getting back into Truckee requires a climb to over 12,000 feet to safely get back in. The surrounding routes back in might have you starting the engine at 5-6k. Very marginal or impossible if you used the engine for self launch at the beginning of the day. In contrast the DG 800 will climb to well over 14k, personally in the winter I took off from sea level and climbed to 16k and it was still gaining 100-200 FPM. Recharging the gas tank takes less than 5 minutes for 5 gallons of fuel. When the battery's reach a much higher level of capacity and are able to be recharged in a different way, the electric glider will come of age, and i have no doubt they will. The backing to behind this push is driven by electric cars. Asking any one who owns a pure electric car and hear their stories on range anxiety. ONLY Tesla usiong super chargers do you see a charge time to drive time much less than one. My Volt is horrible! From a 110vac socket pulling 8 amps, it takes over 12 hours to get 40 minutes of driving time at 60 mph.

It is strange to hear "When the battery's reach a much higher level of capacity
and are able to be recharged in a different way, the electric glider will come of
age", as the number in service and on order increase quickly, and the pilots are
smiling broadly. The current batteries a quite sufficient for a lot of pilots,
especially for FES pilots.

I've flown my ASH 26 E for 25 years, so I have plenty of experience with the range
I use and want. Based on that experience (over 4000 hours), I decided the GP15
with the large battery would easily handle all but a few of the self-retrieve
situations I've encountered. Those few situations can be avoided by turning around
in flight a bit sooner, or accepting a car or towplane retrieve every few years.

Recharging the batteries may be the more difficult problem, but at the places I
normally fly, all have at least one of these choices:

- plugging in to the FBO sockets, RV campground power pedestals, or friend's hangars
- charging with my RV's generator, or with a portable generator
- taking the batteries to the motel for charging

Your judgement is based on how you operate, but your criteria are not universal,
as I have indicated. If we went by your DG 800 comparison, no one would be flying
an FES, and a pure glider would never fly from Truckee!

--
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