Best Overall Motorglider available today?

The EB29 with 25M span is listed at 63, same as the 21 M span JS2. Four more
meters doesn't buy you what it used to!

jfitch wrote on 10/6/2020 8:39 AM:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I think it is best explained by a mistake in their math. I'd be interested in seeing the test data proving it.

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini wrote:
Thank you for your first hand infos, those are good news for me (I don't understand why they advertise these dimensions in a different way). JS2 seems to be a nice project overall. Hard to me to understand where they streched out those +4 points of efficency in 21m, according to their calculated polars, compared to ASH31 (yes I know that '31 profiles are a bit superseeded and the aspect ratio is a factor too but 4 points are a huge amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not be comparable - one internal cockpit rim and one external I guess. The 525mm shoulder width for the JS2 is exactly the same as the quoted figure for the JS1 (and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31 from which it was derived. I have 4 years in a JS1 followed by 2 in the ASH 26e and they are so similar that it would be hard to know which cockpit I was in with my eyes closed. Looking at the JS2 cockpit photographs it obvious that its structural cockpit rim design is the same as the 31, 26 and JS1. JS do not make small cockpits.


--
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

At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I
th=
ink it is best explained by a mistake in their math. I'd be interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me (I
don't
=
understand why they advertise these dimensions in a different way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The 525mm
should=
er width for the JS2 is exactly the same as the quoted figure for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the ASH
26e
=
and they are so similar that it would be hard to know which cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and JS1.
JS
=
do not make small cockpits.

I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH its
few improvements on the JS1C should achieve that....

Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I
th=
ink it is best explained by a mistake in their math. I'd be interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me (I
don't
=
understand why they advertise these dimensions in a different way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The 525mm
should=
er width for the JS2 is exactly the same as the quoted figure for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the ASH
26e
=
and they are so similar that it would be hard to know which cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and JS1.
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH its
few improvements on the JS1C should achieve that....

The JS website says it's 60 for the JS1C/21M; 63 for the JS2/21M.

jfitch wrote on 10/6/2020 1:37 PM:
Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I
th=
ink it is best explained by a mistake in their math. I'd be interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me (I
don't
=
understand why they advertise these dimensions in a different way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The 525mm
should=
er width for the JS2 is exactly the same as the quoted figure for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the ASH
26e
=
and they are so similar that it would be hard to know which cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and JS1.
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH its
few improvements on the JS1C should achieve that....



--
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

[quote='Eric Greenwell[_4_];1030860']The EB29 with 25M span is listed at 63, same as the 21 M span JS2. Four more
meters doesn't buy you what it used to!

Only a lower span loading

:-) Colin

At 20:58 06 October 2020, Eric Greenwell wrote:
The JS website says it's 60 for the JS1C/21M; 63 for the JS2/21M.

jfitch wrote on 10/6/2020 1:37 PM:
Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of
56:1.
I
th=
ink it is best explained by a mistake in their math. I'd be
interested
in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me
(I
don't
=
understand why they advertise these dimensions in a different
way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where
they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly
not
be
compa=
rable - one internal cockpit rim and one external I guess. The
525mm
should=
er width for the JS2 is exactly the same as the quoted figure for
the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the
ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the
ASH
26e
=
and they are so similar that it would be hard to know which
cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and
JS1.
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH
its
few improvements on the JS1C should achieve that....



--
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.../download-the-
guide-1



Yes they say 60:1 for the JS1, but Idafleig measured it at 63:1 - there is

a Youtube video where Uys states this somewhere maybe this one
https://youtu.be/yoek1na7L98 - if your that interested contact Jonkers
yourself ..... or buy one and measure it yourself...... the JS5 will be
70:1
with 24m..

On Tuesday, October 6, 2020 at 9:48:47 AM UTC-7, Eric Greenwell wrote:
2G wrote on 10/6/2020 8:33 AM:
On Monday, October 5, 2020 at 3:37:33 PM UTC-7, Dave Nadler wrote:
On Sunday, October 4, 2020 at 8:04:18 PM UTC-4, 2G wrote:
The telling difference for was when I did a 30nm glide at Ely in my 26e
with an ASG29; I ended up 3,000ft below him!

Apologies all, I guess Tom's '26 perhaps isn't the "Best Overall Motorglider Available Today"...

Moral of the story: wing loading matters.

Tom

So, you were flying too fast for your wing loading, trying to keep up with the 29?

--
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

No, we were gliding at the same speed, but not flying wingtip to wingtip.

Tom

On Tuesday, October 6, 2020 at 1:58:06 PM UTC-7, Eric Greenwell wrote:
The JS website says it's 60 for the JS1C/21M; 63 for the JS2/21M.

jfitch wrote on 10/6/2020 1:37 PM:
Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I
th=
ink it is best explained by a mistake in their math. I'd be interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me (I
don't
=
understand why they advertise these dimensions in a different way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The 525mm
should=
er width for the JS2 is exactly the same as the quoted figure for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the ASH
26e
=
and they are so similar that it would be hard to know which cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and JS1.
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH its
few improvements on the JS1C should achieve that....



--
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

Someone might ask them how they came up with these L/D figures because I understand that they aren't from actual flight tests.

Tom

At 04:12 08 October 2020, 2G wrote:
On Tuesday, October 6, 2020 at 1:58:06 PM UTC-7, Eric Greenwell
wrote:
The JS website says it's 60 for the JS1C/21M; 63 for the JS2/21M.

jfitch wrote on 10/6/2020 1:37 PM:
Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of
56:1. I
th=
ink it is best explained by a mistake in their math. I'd be
interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo
Orsini
wrote:
Thank you for your first hand infos, those are good news for
me (I
don't
=
understand why they advertise these dimensions in a different
way).
JS2
see=
ms to be a nice project overall. Hard to me to understand
where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a
bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are
clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The
525mm
should=
er width for the JS2 is exactly the same as the quoted figure
for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the
ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in
the
ASH
26e
=
and they are so similar that it would be hard to know which
cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs
it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26
and
JS1.
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2
witH
its
few improvements on the JS1C should achieve that....



--
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.../download-the-
guide-1

Someone might ask them how they came up with these L/D figures
because I
understand that they aren't from actual flight tests.

Tom


THE JS1C TO MY KNOWLEDGE HAS BEEN MEASURED AT 63:1 BY THE
IDAFLEIG IN ITS FLIGHT TESTS- PROBABLY THE MOST RELIABLE WAY
OF MEASURING A GLIDERS POLAR. (I THINK THE JONKERS BOYS
WHERE SUPRISED BY THAT FIGURE AS IT IS RARE FOR A GLIDER TO
EXCEED ITS THEOROTICAL FIGURE -BUT IT DOES HAPPEN.) ALL
MANUFACTURERS FIGURES ARE AT BEST 'THEORETICAL' UNTIL
MEASURED.................. SOME ARE WILDLY OPTIMISTIC - BUT BEST L/D
DOESNT MEAN MUCH THESE DAYS REALLY................. ITS NOT AS
THOUFGH THIS AIRCRAFT AS NOT PROVED ITSELF IN THE CONTEST
ARENA IS IT.......

Idaflieg measurements are never published to the public.

Le mardi 6 octobre 2020 Ã* 22:37:22 UTC+2, jfitch a écritÂ*:
Link? Google produces zero results.
On Tuesday, October 6, 2020 at 1
1:00:06 AM UTC-7, Paul T wrote:
At 15:39 06 October 2020, jfitch wrote:
They are claiming 63:1, that is 7 points higher than AS claim of 56:1. I
th=
ink it is best explained by a mistake in their math. I'd be interested in
s=
eeing the test data proving it.=20

On Tuesday, October 6, 2020 at 12:53:25 AM UTC-7, Carlo Orsini
wrote:
Thank you for your first hand infos, those are good news for me (I
don't
=
understand why they advertise these dimensions in a different way).
JS2
see=
ms to be a nice project overall. Hard to me to understand where they
strech=
ed out those +4 points of efficency in 21m, according to their
calculated
p=
olars, compared to ASH31 (yes I know that '31 profiles are a bit
superseede=
d and the aspect ratio is a factor too but 4 points are a huge
amount!!).
Those two dimensions for the JS2 and the ASH31 are clearly not
be
compa=
rable - one internal cockpit rim and one external I guess. The 525mm
should=
er width for the JS2 is exactly the same as the quoted figure for the
JS1
(=
and JS3) and the JS1 cockpit roominess is fully equal to the ASH26/31
from
=
which it was derived. I have 4 years in a JS1 followed by 2 in the ASH
26e
=
and they are so similar that it would be hard to know which cockpit I
was
i=
n with my eyes closed. Looking at the JS2 cockpit photographs it
obvious
th=
at its structural cockpit rim design is the same as the 31, 26 and JS1..
JS
=
do not make small cockpits.
I believe the Idafleig measured a JS1C at 63:1......so the JS2 witH its
few improvements on the JS1C should achieve that....