Reiner Stemme's new electric glider.

Being announced at Aero 2016 this week is Dr Stemmes new glider designs.

Not in english as yet but here is some detail.

http://www.rs-uas.com/products/sk10e-elfin/preface/

This is his new company. Reiner Stemme Utility Air Systems.

So he has nothing to do with old Stemme company? Interesting.

Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.

Not speaking German and too lazy to do a lot of cutting and pasting in
google translate, I'll ask he What is the range capability with the
range extender? And how long does it take to recharge? Does it have
some solar charging capability?

My old-fashioned fossil fuel powered Stemme will take off, climb to
14,000' (30,000' service ceiling, but that's just too cold), cruise for
500 miles at about 130 kts ground speed, and can be "recharged" in about
10 minutes at the pump. That's pretty hard to beat! That said, since
bringing it home I've flown it around 13 hours and used about 11 gallons
of gas, maybe 12... As the season improves, I'll probably be able to
fly another 25 or 30 hours before needing to refuel (unless I want the
ballast).

On 4/21/2016 1:51 AM, krasw wrote:
So he has nothing to do with old Stemme company? Interesting.

Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.

--
Dan, 5J

On Thursday, 21 April 2016 17:19:05 UTC+3, Dan Marotta wrote:
Not speaking German and too lazy to do a lot of cutting and pasting
in google translate, I'll ask he* What is the range capability
with the range extender?* And how long does it take to recharge?*
Does it have some solar charging capability?



My old-fashioned fossil fuel powered Stemme will take off, climb to
14,000' (30,000' service ceiling, but that's just too cold), cruise
for 500 miles at about 130 kts ground speed, and can be "recharged"
in about 10 minutes at the pump.* That's pretty hard to beat!* That
said, since bringing it home I've flown it around 13 hours and used
about 11 gallons of gas, maybe 12...* As the season improves, I'll
probably be able to fly another 25 or 30 hours before needing to
refuel (unless I want the ballast).




On 4/21/2016 1:51 AM, krasw wrote:



So he has nothing to do with old Stemme company? Interesting.

Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.





--

Dan, 5J

1.000 km mit 185 km/h TAS (100 KTAS)

On Thu, 21 Apr 2016 08:18:53 -0600, Dan Marotta wrote:

Putting range extender on glider is a good idea. They are being made
everywhere for electric cars and should be affordable (when mass
produced). Surprising that the weight of pod is 100kg. That's one big
range extender. No wonder they couldn't fit it in the fuselage.

Not that surprising: the energy density of LiPoly/Li-ion batteries is low
by comparison with avgas.

A quick look round Wikipedia gives a figure of 0.1-0.25Kw/kg for Li-ion
batteries and 33.3kw/US gal. Since a US gallon of gas weighs 6.073 lbs
and there are 2.2 lbs to a kilogram, that gives 12Kw/kg for gasoline.
IOW on their figures gasoline has at least 48 times the energy density of
Li-ion batteries.

Now you know why the long range S-class Tesla totes 540kg of battery,
while a full tank in my Focus weighs around 50kg - (55 litres of petrol +
guessed 5kg of steel). Both have a similar driving range +/- 20%.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Thu, 21 Apr 2016 19:00:19 +0000, Martin Gregorie wrote:

IOW on their figures gasoline has at least 48 times the energy density
of Li-ion batteries.

On thinking about it, an energy density of 0.1-0.3 Kw/Kg seems a bit low
for a Li-ion/Li-poly battery and I'm wondering how old and outdated it
might be.

.... the long range S-class Tesla totes 540kg of battery,
while a full tank in my Focus weighs around 50kg - (55 litres of petrol
+ guessed 5kg of steel). Both have a similar driving range +/- 20%.

Comparing the S-class battery with my Focus fuel tank gives a an energy
density ratio (kw/kg) nearer 1:10 than the 1:48 given by Wikipedian
figures.

Does anybody have recent figures for best-of-breed Li-ion or similar
batteries?



--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Does anybody have recent figures for best-of-breed Li-ion or similar
batteries?

From what I gather from the translation is the pod is a self contained generator powered by a small gas engine. Complete with fuel tank. It plugs into the glider system and is used to provide a constant charge to keep the main batteries topped up. While soaring I assume it would be turned off and only run when needed. Maybe some solar panels on top of the fuse as well.

Not touring? Leave it in the hanger.