Which 18m FES sailplane to buy?

On Wednesday, 9 December 2015 01:10:25 UTC+2, Casey Cox wrote:
I can understand why one would want a specific glider if one was planning to compete, but with so many more advantages of having a 13.5m, I wonder why more people do not consider them.

The performance of 13.5m gliders is a lot lower than even previous generation glass/carbon gliders. Most of the 13.5m gliders have max L/D's in the high 30's or low 40's and their performance drops drastically when some speed is added (typically 2m/s sink rate at around the 170km/h mark). Their lower wing loading limitations doesn't lend them for the booming weather found in Africa/Australia/Western USA.
Most of them also have much lower Vne's (around the 220 to 230km/h mark) and this becomes an issue at higher altitudes where one becomes Vne limited.

The only benefit that I can see in owning a 13.5m glider is easier rigging and derigging due to lower weight components but I'm not age limited yet.

On Wednesday, December 9, 2015 at 12:38:14 AM UTC-5, Surge wrote:
On Wednesday, 9 December 2015 01:10:25 UTC+2, Casey Cox wrote:
I can understand why one would want a specific glider if one was planning to compete, but with so many more advantages of having a 13.5m, I wonder why more people do not consider them.

The performance of 13.5m gliders is a lot lower than even previous generation glass/carbon gliders. Most of the 13.5m gliders have max L/D's in the high 30's or low 40's and their performance drops drastically when some speed is added (typically 2m/s sink rate at around the 170km/h mark). Their lower wing loading limitations doesn't lend them for the booming weather found in Africa/Australia/Western USA.
Most of them also have much lower Vne's (around the 220 to 230km/h mark) and this becomes an issue at higher altitudes where one becomes Vne limited..

The only benefit that I can see in owning a 13.5m glider is easier rigging and derigging due to lower weight components but I'm not age limited yet.

I figured that but seeing someone else actually state it helps. The other advantage you missed is Self Launch. I did not realize that Vne limitation became a problem. (Haven't got there yet).

It just seems more manufactures are building 13.5m (LAK just introduced the Mini Lak at the 1st International 13.5m), and I wonder what sales are of 13.5m compared to 15m and 18m.

I'm hoping in 4-5 yrs I can be in a position to upgrade to an FES.

I have ordered a GP12 E FLEX. The -2ms speed is 185kph at max allowed
wingloading (45kg/m2). The VELO will be better than that. It is self
launching of course, and the electric motor is not FES but on a pylon. This
is preferable to FES because with a folding prop there is very little drag
with the pylon out, and it is much more efficient aerodynamically, no FES
drag (1% or so), and less battery drain! Retract takes only 5 secs anyway.
Obviously an ultralight cannot compete with a fully ballasted 18m racer,
but then look at the price difference, 50% including a trailer! QED


At 13:46 09 December 2015, Casey Cox wrote:
On Wednesday, December 9, 2015 at 12:38:14 AM UTC-5, Surge wrote:
On Wednesday, 9 December 2015 01:10:25 UTC+2, Casey Cox wrote:
I can understand why one would want a specific glider if one was
planni=
ng to compete, but with so many more advantages of having a 13.5m, I
wonder=
why more people do not consider them.
=20
The performance of 13.5m gliders is a lot lower than even previous
genera=
tion glass/carbon gliders. Most of the 13.5m gliders have max L/D's in
the
=
high 30's or low 40's and their performance drops drastically when some
spe=
ed is added (typically 2m/s sink rate at around the 170km/h mark). Their
lo=
wer wing loading limitations doesn't lend them for the booming weather
foun=
d in Africa/Australia/Western USA.
Most of them also have much lower Vne's (around the 220 to 230km/h
mark)
=
and this becomes an issue at higher altitudes where one becomes Vne
limited=
..
=20
The only benefit that I can see in owning a 13.5m glider is easier
riggin=
g and derigging due to lower weight components but I'm not age limited
yet.

I figured that but seeing someone else actually state it helps. The
other
=
advantage you missed is Self Launch. I did not realize that Vne
limitation=
became a problem. (Haven't got there yet).

It just seems more manufactures are building 13.5m (LAK just introduced
the=
Mini Lak at the 1st International 13.5m), and I wonder what sales are of
1=
3.5m compared to 15m and 18m.

I'm hoping in 4-5 yrs I can be in a position to upgrade to an FES.

On Wednesday, 9 December 2015 15:46:55 UTC+2, Casey Cox wrote:
I figured that but seeing someone else actually state it helps. The other advantage you missed is Self Launch. I did not realize that Vne limitation became a problem. (Haven't got there yet).

I didn't miss the self launch option as one can already purchase self launch gliders new or second hand so there is no particular advantage to a 13.5m self launcher.
If I'm not mistaken there is a self-launch option for the LAK 17B FES so FES self-launch is possible on longer wingspan gliders too even if it's not that popular yet.

It comes down to cost vs performance and if I had the choice I'd rather spend the money on a second hand, 18m, petrol powered self launcher than on a new 13.5m FES glider simply due to bang-for-buck. But then again I'm one of those types who doesn't replace my vehicle every three years and couldn't care about driving the latest and greatest. I'm sure the 13.5m gliders are plenty of fun to fly.

Yes 13.5 gliders are great fun, especially for the recreational pilot.
But the problems with longer span gliders here in Europe are the
restrictions
imposed by EASA on certified aircraft. With UL, flying costs are lower too
- no aerotows, self maintenance, smaller batteries for electric power etc.
etc.
Used new-design 18m self-launchers are still way more expensive than
13.5m gliders.
If cost is not an issue then just wait 3 years for the latest super-yacht!

At 05:40 10 December 2015, Surge wrote:
On Wednesday, 9 December 2015 15:46:55 UTC+2, Casey Cox wrote:
I figured that but seeing someone else actually state it helps. The
othe=
r advantage you missed is Self Launch. I did not realize that Vne
limitati=
on became a problem. (Haven't got there yet).

I didn't miss the self launch option as one can already purchase self
launc=
h gliders new or second hand so there is no particular advantage to a
13.5m=
self launcher.
If I'm not mistaken there is a self-launch option for the LAK 17B FES so
FE=
S self-launch is possible on longer wingspan gliders too even if it's not
t=
hat popular yet.

It comes down to cost vs performance and if I had the choice I'd rather
spe=
nd the money on a second hand, 18m, petrol powered self launcher than on
a
=
new 13.5m FES glider simply due to bang-for-buck. But then again I'm one
of=
those types who doesn't replace my vehicle every three years and
couldn't
=
care about driving the latest and greatest. I'm sure the 13.5m gliders
are
=
plenty of fun to fly.

Another advantage to the 13.5 meter gliders like the Silent is that when fitted with an FES system they are not just sustainers but self-launchers. Hence the Silent Electro is a real self-launcher. No more waiting for a $50 tow.