Best option for electric self starting glider

On Tuesday, April 14, 2020 at 1:00:45 AM UTC-4, 2G wrote:
On Monday, April 13, 2020 at 9:49:26 PM UTC-7, wrote:
On Monday, April 13, 2020 at 9:37:18 AM UTC-7, Duster wrote:
Any opinions on the Taurus Electro? Side-by-side, pylon, self-launch, trailer option for solar array charging, etc. They claim the profile of the cockpit/fuselage acts like a lifting body.

There are 4 Electro's in the USA and about a dozen Rotax powered. I've flown a Rotax-powered one for about 10 years, but only have a few flights in an Electro. It flies like an older generation, lightly loaded 15 meter ship. Lots of fun soaring, but not for unhandicapped competition or records.

The company's objective in designing the electric version was to have it achieve the same performance, at the same price, as the gas powered. I understand that the electric will climb slightly faster (bigger prop, IIRC), and the price probably isn't that much more than the Rotax version. I think the empty weight is similar, though the batteries consume a lot of space.

But the run time, like all of the electrics, is the big difference. I think Pipistrel used to advertise 6,000' of climb on a charge, though that was a while back and they probably have better numbers today. (The Rotax powered version has a max fuel capacity of something like 14 gallons (with dual tanks). I have only the single tank configuration, but have never had "range anxiety" with probably over an hour of run time, should it be needed.. (Typical flight has 5-7 minutes for initial launch and another 5-10 minutes of run time if I need a relight, and I would guess that the Electros have a similar profile.))

The solar trailer for the Electro is quite cool. You can park at an unelectrified gliderport, and the sun charges the battery array in the trailer. Then you hook-up your Taurus overnight and recharge the on-board batteries. Rinse and repeat.

Pipistrel has a big lead over others in actual, in-the-field application and improvements vs. projected and theoretical systems. If they elected to market their systems in a higher-performance sailplane I think they would have a superior product.

For VFR cross country flight the FAA requires you to have a 30 minute fuel reserve. Note that electric gliders don't even have 30 minutes of run time, let alone a reserve. All this discussion assumes running the battery totally flat - no reserve WHATSOEVER and perfect battery performance (no degradation for temperature or age). This is an unacceptable level of even token, lip-service safety. GIVE ME A BREAK!

Tom

- I guess I should never venture out flying my motorless (pure) glider, since it has no fuel reserve at all! :-)

2G wrote on 4/13/2020 10:00 PM:
Note that electric gliders don't even have 30 minutes of run time, let alone a reserve. All this discussion assumes running the battery totally flat - no reserve WHATSOEVER and perfect battery performance (no degradation for temperature or age). This is an unacceptable level of even token, lip-service safety. GIVE ME A BREAK!

Actually, several of them do exceed 30 minutes run time; eg, the Jeta with the
large battery has a nominal 150km range under power. That's at about 100kph,
yielding a 90 minute run, and a few minutes longer if you include the launch and
climb to 2500' AGL. The AS34 has a similar run time, the miniLak about 60 minutes,
plus launch time.

The discussion does not assume running the batteries totally flat; eg, the GP15
battery is limited to a 90% discharge to greatly extend it's life. Of course,
temperature and age will affect performance, as it can with gasoline gliders.
Electrics do have an advantage at high density altitudes: their power remains
constant, unlike a gas engine.

As for safety, most motorglider pilots know the engine is to be treated as a
convenience, and not an insurance policy. Like a pure glider, we should always be
within gliding reach of a safe landing place.

--
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

On Monday, April 13, 2020 at 9:00:45 PM UTC-8, 2G wrote:
On Monday, April 13, 2020 at 9:49:26 PM UTC-7, wrote:
On Monday, April 13, 2020 at 9:37:18 AM UTC-7, Duster wrote:
Any opinions on the Taurus Electro? Side-by-side, pylon, self-launch, trailer option for solar array charging, etc. They claim the profile of the cockpit/fuselage acts like a lifting body.

There are 4 Electro's in the USA and about a dozen Rotax powered. I've flown a Rotax-powered one for about 10 years, but only have a few flights in an Electro. It flies like an older generation, lightly loaded 15 meter ship. Lots of fun soaring, but not for unhandicapped competition or records.

The company's objective in designing the electric version was to have it achieve the same performance, at the same price, as the gas powered. I understand that the electric will climb slightly faster (bigger prop, IIRC), and the price probably isn't that much more than the Rotax version. I think the empty weight is similar, though the batteries consume a lot of space.

But the run time, like all of the electrics, is the big difference. I think Pipistrel used to advertise 6,000' of climb on a charge, though that was a while back and they probably have better numbers today. (The Rotax powered version has a max fuel capacity of something like 14 gallons (with dual tanks). I have only the single tank configuration, but have never had "range anxiety" with probably over an hour of run time, should it be needed.. (Typical flight has 5-7 minutes for initial launch and another 5-10 minutes of run time if I need a relight, and I would guess that the Electros have a similar profile.))

The solar trailer for the Electro is quite cool. You can park at an unelectrified gliderport, and the sun charges the battery array in the trailer. Then you hook-up your Taurus overnight and recharge the on-board batteries. Rinse and repeat.

Pipistrel has a big lead over others in actual, in-the-field application and improvements vs. projected and theoretical systems. If they elected to market their systems in a higher-performance sailplane I think they would have a superior product.

For VFR cross country flight the FAA requires you to have a 30 minute fuel reserve. Note that electric gliders don't even have 30 minutes of run time, let alone a reserve. All this discussion assumes running the battery totally flat - no reserve WHATSOEVER and perfect battery performance (no degradation for temperature or age). This is an unacceptable level of even token, lip-service safety. GIVE ME A BREAK!

Tom

The 30 minutes is a flight planning requirement for Airplanes....Helicopters 20 minutes. For the glider category there is no such flight planning requirement.

Thanks to those providing opinions/experiences with the Taurus Electro. I asked my local dealer if Pipistrel was planning on a longer wing. His reply was "The planform is a more forward sweep with a slight increase in span. it will be a 4 piece wing with the outer sections easily removable to permit hangaring in European smaller T-hangars. L/D 43:1 or slightly better. The wing will be plug and play with all current Taurus Electro G2.5 fuselages. Not sure if it will be plug and play with Taurus M fuselages.There is no estimated in service date as of yet."

I see that the same circular arguments and dogmatic thinking exists in the
wider world of gliding as it does in UK gliding.

On the topic of powered gliders, one side will argue that this is the way
the market is heading and that one of the benefits is faster turnaround and
fewer people required for launches.
The other side will engage in circular logic and argue that it is safer to
fly aircraft without engines as using an engine introduces the possibility
of engine failure.

My opinion:
Do as you like.
Buy a powered glider, preferably an SSDR, if that's what you want.
If your club is headed up by old-school dogmatic individuals who won't
'allow' you to fly from the site, find somewhere better.

I'll describe the requirements I am trying to satisfy for me with my project. I suspect this is much like many but obviously not all.
1) The glider needs to be practical for one person to assemble in a reasonable period of time without heavy lifting. This means a ship that is not more than about 100 lb heavier than it's similar non powered counterpart.
2) Self launch capability with acceptable margins. I am using a takeoff distance of 900 feet, off pavement, and climb rate of at least 400 feet per minute. Ability to fly off unpaved surface knowing takeoff distance will increase.
3) Battery capacity for a 2000 foot launch and 2500 feet reserve to save and get home or to a safe airport.
4)System must have sufficient motor cooling to allow high power settings long enough to get to a safe altitude before power reduction.
5) Practical charging. In my project the battery can be removed for charging away from the glider.
6) Existing proven airframe.
This is my "Wednesday afternoon" ship for when I have no tow pilot.
FWIW
UH

In response to UH criteria above I would like to chime in with the AMS-Flight Carat meets all of the criteria except for being electric and how happy I am with my AMS-Flight Carat. Decent performance launching in the summers out of Moriarty, Parowan and Eli. This will be my 3rd season with her and still love it. Factory is still taking orders.

LOV2AV8 wrote on 4/14/2020 1:41 PM:
I'll describe the requirements I am trying to satisfy for me with my project. I suspect this is much like many but obviously not all.
1) The glider needs to be practical for one person to assemble in a reasonable period of time without heavy lifting. This means a ship that is not more than about 100 lb heavier than it's similar non powered counterpart.
2) Self launch capability with acceptable margins. I am using a takeoff distance of 900 feet, off pavement, and climb rate of at least 400 feet per minute. Ability to fly off unpaved surface knowing takeoff distance will increase.
3) Battery capacity for a 2000 foot launch and 2500 feet reserve to save and get home or to a safe airport.
4)System must have sufficient motor cooling to allow high power settings long enough to get to a safe altitude before power reduction.
5) Practical charging. In my project the battery can be removed for charging away from the glider.
6) Existing proven airframe.
This is my "Wednesday afternoon" ship for when I have no tow pilot.
FWIW
UH

In response to UH criteria above I would like to chime in with the AMS-Flight Carat meets all of the criteria except for being electric and how happy I am with my AMS-Flight Carat. Decent performance launching in the summers out of Moriarty, Parowan and Eli. This will be my 3rd season with her and still love it. Factory is still taking orders.

I've often wondered why the Carat was not more popular, as it seemed like good
compromise. What is the cost for a new one delivered to the US?


--
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

I know of a Silent 2 FES that had a prop strike on takeoff. Took an inch or 2 off both props. Pilot continued the launch. Said from his perspective he suspected a strike but the glider seemed to power and fly okay. Motor was fine; don’t even think it required an inspection. Got new props. I’ve watched a FES prop balancing exercise. Looked like it required special equipment and was rather tedious. Anyone have information on that process?

Danny Brotto
LS-8/18 "P6"

Magnus,

What did you decide about electric self launch?

--- Alex (Willamette Valley Soaring Club)

On Wednesday, January 20, 2021 at 3:10:40 PM UTC+10, Alex Lamb wrote:
Magnus,

What did you decide about electric self launch?

--- Alex (Willamette Valley Soaring Club)

I don't know what Magnus ordered, but my aforementioned Diana 2NG-FES arrived about a month after my post, and you can see the results:
https://www.youtube.com/watch?v=3clSlZUPI3w

I will make some better videos in the coming months.