Which sustainer system would you chose for your sailplane?

On Wednesday, January 6, 2016 at 5:14:56 PM UTC-5, SF wrote:
How about a solid rocket JATO type unit for a sustainer.

I initially toyed with the idea of a single-use 3000 foot climb save-my-ass FES cost effectively powered by a boatload of alkaline D-cells. But I soon realized how much a FES would extend my range in routine use. That mountain ridge to the west that we rarely fly over because the cloudbase is rarely more than 500 feet higher? It takes hours to do an auto retrieve from the far side.

Why not go west, explore, use FES to get home if the cloudbase drops in the meantime. I want one.

This thread was originally about types of sustainer. Just a note, while the jet engines sound cool, they are effectively the same weight as a solo sustainer with the required fuel, they need a lot of fuel. and you cannot windmill them. For me a retractable small sustainer would be the best. Unfortunately the ASG-32 is the only such glider. Wish there was a single seat 18 meter with retractable electric sustainer.

For the cost I would get a self launcher vice a sustainer. I know the Lak 17 FES can launch but I think they were originally and maybe still calling it a sustainer. For that kind of money I would want the glider manufacture to endorse launch. I think the Mini Lak and the Silent endorse launch. I would hate to have over 100k in a glider and self launch and something go wrong and insurance not pay off because I was launching a sustainer. Please correct me if I'm wrong.

I do like the ease of use of the FES and think its great

At 01:24 07 January 2016, Casey wrote:
For the cost I would get a self launcher vice a sustainer. I
know the Lak
=
17 FES can launch but I think they were originally and
maybe still calling
=
it a sustainer. For that kind of money I would want the
glider
manufacture=
to endorse launch. I think the Mini Lak and the Silent
endorse launch.
I=
would hate to have over 100k in a glider and self launch
and something go
=
wrong and insurance not pay off because I was launching a
sustainer.
Pleas=
e correct me if I'm wrong.

I do like the ease of use of the FES and think its great


It's quite simple: it's either a self launch sailplane or not:
look at the specifications.
Additionally you are mixing Ultralights (the Silent) with
conventional sailplanes (the LAK17B FES). My understanding
is that is NOT legal, in Europe, to self launch the LAK17BFES
(or indeed any other true "sustainer" sailplane). It's been
done of course but it makes no sense with an electric power
plant, what little battery power you started with has now
gone so you have no useful sustainer performance left. Why
would you even think that's a good idea?

The Silent Electro is a different (lighter) animal, designed as
a self launch. You could launch to a modest height and have
some sensible retrieve capability but you're sitting in a
fragile (compared to a modern sailplane) structu lower Va,
lower Vne etc. It's very nicely built and a joy to rig. It's not
much cheaper than a LAK17BFES......choices.

On Thursday, January 7, 2016 at 8:45:05 AM UTC-5, Dave Walsh wrote:
At 01:24 07 January 2016, Casey wrote:
For the cost I would get a self launcher vice a sustainer. I
know the Lak
=
17 FES can launch but I think they were originally and
maybe still calling
=
it a sustainer. For that kind of money I would want the
glider
manufacture=
to endorse launch. I think the Mini Lak and the Silent
endorse launch.
I=
would hate to have over 100k in a glider and self launch
and something go
=
wrong and insurance not pay off because I was launching a
sustainer.
Pleas=
e correct me if I'm wrong.

I do like the ease of use of the FES and think its great


It's quite simple: it's either a self launch sailplane or not:
look at the specifications.
Additionally you are mixing Ultralights (the Silent) with
conventional sailplanes (the LAK17B FES). My understanding
is that is NOT legal, in Europe, to self launch the LAK17BFES
(or indeed any other true "sustainer" sailplane). It's been
done of course but it makes no sense with an electric power
plant, what little battery power you started with has now
gone so you have no useful sustainer performance left. Why
would you even think that's a good idea?

The Silent Electro is a different (lighter) animal, designed as
a self launch. You could launch to a modest height and have
some sensible retrieve capability but you're sitting in a
fragile (compared to a modern sailplane) structu lower Va,
lower Vne etc. It's very nicely built and a joy to rig. It's not
much cheaper than a LAK17BFES......choices.

That's kinda my point.

But if I was a manufacture of anything. I would not come out with my best to begin with. I would come out with a sustainer and let the high rollers buy. Then come out with a more powerful self launcher. The high rollers will sell their sustainers for the self launchers. I bet auto manufactures do this as well as other companies.

I realize the specs of the Lak and Silent 2 Electro. Same system in 15m gliders. I would not call the Silent a ultralight with an empty wt of 452 lbs and VNe 137 mph. I would call it a 13.5m conventional. Just like I would not classify a 15m with an 18m or 20m. All are different. Now the Sparrow Hawk I would classify as Ultralight.

And for the sake of discussion I can substitute the GP 14 VELO for the Silent 2. Same VNe as and empty wt as Lak 17. http://www.gpgliders.com/gp-14-e-velo

13.5m class= Alisport Silent, GP 14 Velo, Mini Lak, Albastar AS 13.5,

And you are right...Its a sustainer or self launcher. Just like its a 13.5m or 15m or 18m or 20m, flapped or not.

I'm just saying I would not spend the money on a sustainer if I could get a self launcher. Someone that lives closer to a tow would choose differently.

Jets may be more thirsty than 2 stroke sustainers but the extra power and speed makes the additional fuel cost pale into insignificance - even more so when you think of it a a proportion of the capital and running costs of a new glider.

Electric will obviously evntually win out but battery technology is advancing only slowly compared to other technologies and the capital costs remain expensive. I don't know the cost of FES batteries but I reckon I could buy around 8000 litres of jet fuel for the cost of a set of Antares batteries - maybe more. I used about 100 litres last summer including a lot of testing rather than retrieve use.

( But I do rather fancy the GP14E Velo!)

While I hear the advantage of other type of power - I think more people are comfortable throwing a switch, than firing up a jet or hoisting a boom. And I have never been around any engine that uses fuel and did not smell bad.

Plus you have to explain to your wife that you just purchased a jet, when she thought you were going to fly around the airport safe and sound lol

I still think pilots who are real racing pilots will go powerless and the vast majority of us would be more comfortable flipping a switch even if a Jet has that 007 appeal.

WH1

At 19:35 07 January 2016, wrote:
Jets may be more thirsty than 2 stroke sustainers but the
extra power and
s=
peed makes the additional fuel cost pale into insignificance
- even more
so=
when you think of it a a proportion of the capital and
running costs of a
=
new glider.

Electric will obviously evntually win out but battery
technology is
advanci=
ng only slowly compared to other technologies and the
capital costs remain
=
expensive. I don't know the cost of FES batteries but I
reckon I could
bu=
y around 8000 litres of jet fuel for the cost of a set of
Antares
batteries=
- maybe more. I used about 100 litres last summer
including a lot of
test=
ing rather than retrieve use.

( But I do rather fancy the GP14E Velo!)

Well either you are buying really expensive Jet fuel or you
know a source of really cheap Antares batteries; I'd say you
might buy 20,000+ litres of Jet fuel.

Not sure I'd agree with your thinking on the marketing of the
sustainer and the self-launch glider (ignoring the Ultralights;
incidentally the Silent Electro is an ultralight in Europe).

As a long time owner of several self-launch sailplanes I'd say
self launch buyers and sustainer buyers tend to have different
priorities. Self launchers are heavier, costlier and more
complex: unless you do a lot of flying (say 200 hours per
year) their real running costs are more than a conventional
sailplane. Plus their glide performance, especially in weak
conditions, is worse: this is a real drawback. And when they
breakdown the costs can be truly fantastic: look up the cost of
rebuilding a Solo or rotary engine or, worse, buying a new
engine. Against this is the hard to quantify "independence" and
the ability to get home (usually). Remember all self-launch
owners are complete masters of that branch of accounting
known as "man maths".

Sustainer owners and buyers are a much saner bunch; lower
costs, lighter weight, minor (or nil) performance loss and you
still get home (usually). Not sure many go from sustainer to
self launch? I can see self launch owners going to FES though.
Dave Walsh

On Thursday, January 7, 2016 at 8:45:05 AM UTC-5, Dave Walsh wrote:
My understanding
is that is NOT legal, in Europe, to self launch the LAK17BFES
(or indeed any other true "sustainer" sailplane).

The MINI LAK 13.5 is being developed as a self-launch LSA (European spec LSA). I understand that it would get a Self-launch Experimental Glider Airworthiness Certificate in the USA. It has a lowish pilot weight limitation of 87 kg (192 lbs). It is less expensive than the Silent Electro II FES self-launch. Blanik America has a brochure and quotes a price.