Best Overall Motorglider available today?

At 21:12 08 October 2020, Eric Greenwell wrote:
John Galloway wrote on 10/8/2020 1:09 PM:
On Thursday, 8 October 2020 at 19:39:27 UTC+1, Eric
Greenwell wrote:
I was talking about comparison flights to determine
performance relati=
ve to their
competitors, not absolute L/D measurements. If the JS1C
is really a 63=
:1 glider,
they can relatively easily determine that it's significantly
better th=
an an ASG29,
Ventus 3, ASH 31. etc, by borrowing several of those
gliders and doing=
the tests.
They do not need a calibrated glider for this type of test.

Do you find it easy to believe Jonkers calculations of max
L/D are wro=
ng and low
by 5%? I think they would have corrected their
calculations by now if =
they
believed the Idaflieg's measurement of 63, so that the
numbers for the=
JS2 would
be accurate, yet that is specified at only 63.
Tango Whisky wrote on 10/8/2020 8:45 AM:
If you think that inflight measurements are easy to
make, you are gre=
atly mistaken.
Idaflieg has refined its procedure for over 40 years, and
it is a hug=
e effort:
You have to tow the glider to be measured, and a
calibrated reference=
glider (formerly an Open Cirrus, then a DG300 modified to
17 m, now I th=
ink a Discus 2c 18m) in parallel up to 10'000+ ft very early
in the morni=
ng on a day without convection and fly in free flight at the
various spee=
d points.. One of the tow planes takes pictures along, with
the refernce =
glider's fuselage length as the measure for the difference in
altitude wh=
ich will gradually develop, and the reference glider's polar as
the base =
line. Typically, multiple flights on different days are
conducted in orde=
r to get a decent set of data points. Nowadays, this is
assisted by diffe=
rential GPS data.

If you try to do measurements without a reference
glider, you can't a=
void air movements influencing the measurement (on a high
pressure day wi=
thout convection settled in, the airmass is sinking ever so
slighly, and =
3 cm/s will make for a huge difference at an L/D of 60.

So no, I wouldn't distrust the Idaflieg measurements,
but I would dis=
trust hearsay of the results of those measurements.

Idaflieg will never publish data for a specific reason:
Such data cou=
ld be used for commercial purposes by the manufacturer, or
by their compe=
titors (in the 80's, Nimbus 3 ans ASW22 have never been
measured because =
the result would have risked to put one of the companies out
of business)=
=2E Using data for commercial purposes would lead to a
situation were 5 y=
ears down the road, manufacturers would be very reluctant
to put their gl=
iders at disposition for measurements (and they are usually
put at dispos=
ition by the manufacturers to give them a chance that this
would be the s=
erial number with the best shape ever). Idaflieg is about
science, not pu=
blicity, and its driven by the students of the various Akafliegs.

And yes, you can contact them on their webpage and
inquire about spec=
ific models, and they'll send you a hardcopy for 10 Euros per
set. You ar=
e not allowed to spread it - they have no handle on that, but
if it happe=
nd, nobody would get any copies anymore.

Bert
Ventus cM "TW"
Ex-Akaflieg Braunschweig

Le jeudi 8 octobre 2020 =E0 16:17:30 UTC+2, Eric
Greenwell a =E9crit =
:
It is very hard for me to believe Jonkers calculations
are in error =
by 5% (which
is a lot!), so I suspect the error is the Idaflieg
measurement. Jonk=
ers can, and
likely has, easily do comparison glides itself, to
confirm the perfo=
rmance of
their gliders. Since they stay with the 60:1
specification, why not =
accept their
numbers?
Which gliders have wildly optimistic best L/Ds?
--=20
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...cations/downlo
ad-the=
-guide-1
=20
I don't understand the focus on best LD but when you are
dealing with v=
ery high performance gliders the difference in sink rate for a
difference=
of 3 points is tiny. Even so why compare a 60:1 (or ?63:1)
21m JS1c wi=
th an 18m V3 or ASG29? Judging from Open Class contest
results its only=
relevant competitor is the EB29
=20
My mistake: I looked at the wrong chart on their website.
The JS1C/21M (t=
he 60:1=20
glider) should be compared to other 21M gliders, of course. I
agree the f=
ull polar=20
is important when estimating contest performance, but the
max L/D is ofte=
n a good=20
indication of the rest of the polar for modern sailplanes.

--=20
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...cations/downlo
ad-th=
e-guide-1

As I understand it, the Js1 only really beats other gliders
when the wing loading is high.At one point I was considering
buying one and talking with the agent about the benefits of the
21 M tips.
Their opinion was 21 M was often slower than a well blasted
18. I looked at the polars and was frankly baffled.
At that time they were only fitting panels and enclosures for
jet engines that still had not been certified.
I opted to save a lot of money and buy a second hand
Ventus2ct which I love but has hardly flown this year because
of Covid.(could of rented a light twin for less by the hour!!!)

You bunch of ******* don't believe anything do you, argue amongst
yourselves, thats what you are good at , if you don't want to believe it
fine.

Now that this discussion is totally off in the weeds, I'm wondering
what the conclusion is?



On 9/15/20 11:48 AM, Nick Kennedy wrote:
Didn't want to hijack the current FES tread so I thought I'd start a new one.
This topic came up over dinner a couple of weeks ago.

When you add all the following into a pot and stir, whats the "Best"
Say for Western Great Basin flying.

I think it may be the Carat, but I don't know much about it.
CX thinks its the DG 800 series, but all I know is since he bought that thing its been a endless battle to keep it running. But it does climb well.

FACTORS

Reliability
Maintenance required to keep it running
XC flyability, performance and control feel
Storability
Rigging
Initial cost
High density climb performance
Range
Cockpit layout and seating
Parts availability
Insurance cost
Landing gear complexity
Overall quality
Nick
T

42.

Le vendredi 9 octobre 2020 Ã* 16:47:37 UTC+2, kinsell a écritÂ*:
Now that this discussion is totally off in the weeds, I'm wondering
what the conclusion is?

kinsell wrote on 10/9/2020 7:47 AM:
Now that this discussion is totally off in the* weeds, I'm wondering what the
conclusion is?



On 9/15/20 11:48 AM, Nick Kennedy wrote:
Didn't want to hijack the current FES tread so I thought I'd start a new one.
This topic came up over dinner a couple of weeks ago.

When you add all the following into a pot and stir, whats the "Best"
Say for Western Great Basin flying.

I think it may be the Carat, but I don't know much about it.
CX thinks its the DG 800 series, but all I know is since he bought that thing
its been a endless battle to keep it running.* But it does climb well.

FACTORS

Reliability
Maintenance required* to keep it running
XC flyability, performance and control feel
Storability
Rigging
Initial cost
High density climb performance
Range
Cockpit layout and seating
Parts availability
Insurance cost
Landing gear complexity
Overall quality
Nick
T


Well, the weeds were interesting at times :^)

I hope Nick will tell us _his_ conclusion, since he asked the question. Given his
list of unprioritized factors, the rest of us can't give him the answer. The
discussion illustrates there are many acceptable choices that you have to rank
using your priorities. It also illustrates how motorgliders have a much wider
appeal than 25 years ago, when I got my ASH26E. Back then, the discussion often
focused on whether they were "real" sailplanes; now it's about "which one should I
get". And some, no longer interested in the "real" sailplane argument, are now
eager to argue where to draw a line between "real" self-launchers and "just"
self-retrievers!

--
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 Friday, October 9, 2020 at 12:08:08 PM UTC-6, Eric Greenwell wrote:
kinsell wrote on 10/9/2020 7:47 AM:
Now that this discussion is totally off in the weeds, I'm wondering what the
conclusion is?



On 9/15/20 11:48 AM, Nick Kennedy wrote:
Didn't want to hijack the current FES tread so I thought I'd start a new one.
This topic came up over dinner a couple of weeks ago.

When you add all the following into a pot and stir, whats the "Best"
Say for Western Great Basin flying.

I think it may be the Carat, but I don't know much about it.
CX thinks its the DG 800 series, but all I know is since he bought that thing
its been a endless battle to keep it running. But it does climb well.

FACTORS

Reliability
Maintenance required to keep it running
XC flyability, performance and control feel
Storability
Rigging
Initial cost
High density climb performance
Range
Cockpit layout and seating
Parts availability
Insurance cost
Landing gear complexity
Overall quality
Nick
T


Well, the weeds were interesting at times :^)

Thank you to all that replied to this thread!
Given the above criteria I think probably the best value is the ASH 26E.
They seen to be fairly reliable, go great, service is available.
But a JFitch pointed out these things are expensive, by any benchmark.
Best Regards
Nick
T

What are the issues people are finding with the 31? I talked to a couple of owners that didn't like them and then moved on but never understood what the issues were.
Darren

Darren
I don't know but one of them might be a spouse who is ****ed at a .25 mil asset that sits unused 95-98% of the time.
Nick
T

On Saturday, October 10, 2020 at 5:15:13 PM UTC-4, wrote:
Darren
I don't know but one of them might be a spouse who is ****ed at a .25 mil asset that sits unused 95-98% of the time.
Nick
T
Nick,
This is US soaring problem.
Speed To Fly used in reverse.
If Duo is expensive you have to buy it by yourself.
If 1-26 is cheap we use club buying power.
Europe has this in reverse.
They sure miss something
Ryszard
ps. my favorite motor-glider is Arcus M,
engine is ****,
but glider is soo crazy good if you know how to use its "super glider" flaps,
and you can always find the listener to you long story on a long flight,
and if you old like me, somebody always will bring you home safe .
But It is so expensive, I would loose my wive if I would try to buy one.
Thank you Al and Nico for a chance.

If you own a glider as an investment, perhaps you should consider buying
the Brooklyn Bridge for diversification...

On 10/10/2020 3:15 PM, Nicholas Kennedy wrote:
Darren
I don't know but one of them might be a spouse who is ****ed at a .25 mil asset that sits unused 95-98% of the time.
Nick
T

--
Dan, 5J