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