FES vs Gas Engine – Finding a Thermal?

On Friday, August 25, 2017 at 2:00:07 PM UTC-5, Shaun Murdoch wrote:

:-)

Here in the UK, at the end of the day - when you need the FES, nature
isn't always enough... but it helps!

And sometimes, the FES isn't enough, either. Right, Tony? :-)

Steve Leonard

Twice in my FES career I have not been able to make it back home during a self retrieve. One after a self launch here in Kansas and the second turnpoint of a 300km triangle got washed out. The other time on the day of my day win last month in Hungary, where the last thermal of the day was 100km downwind of home.

Both times the FES got me to an airport where I was then able to get an Aerotow retrieve.

Alisport is working on an extra battery pack for the wings that will double the range and make it less likely that you will have the same experience as me

With my Ventus 2cxm, a pneumatic switch allows the tail TE probe to be switched to Static for the powered climb, which gives a jitter-free vario needle, which while not TE, allows thermals to be clearly recognized and circled in. When at a safe altitude and in a thermal, I stop the engine while continuing the same circle. I have fitted the optional engine brake, which allows the prop to be rapidly stopped from windmilling. I immediately start the prop retracting (I ignore the recommended (high-drag) cool down with prop extended) but after retraction I leave the doors open for a minute for muffler cooling. This minimizes the high-drag retraction period.

Another comment: the only vicious and totally-unexpected spin entry I ever have had in the normally-predicable ventus 2cxm, was when I got too slow while waiting for the prop to stop windmilling (before I fitted the engine brake). A characteristic to remember if trying an inflight start.

Another comment: the only vicious and totally-unexpected spin
entry I ever...

Well that sounds horrible! Are pylon powered sailplane
manufacturers required to demonstrate spin recovery with the
engine out and stopped?

Not flown a Ventus M of any type but this looks like another
example of poor systems design. If the engine retraction sequence
consists of switching off ONE switch (e.g. DG808) or moving one
lever (Antares) then the pilot has nothing to do but control the
airspeed. Many of these other self launch/turbo retract systems
look like an invitation to "finger trouble".

On Saturday, August 26, 2017 at 12:15:08 PM UTC+2, Dave Walsh wrote:
Another comment: the only vicious and totally-unexpected spin
entry I ever...

Well that sounds horrible! Are pylon powered sailplane
manufacturers required to demonstrate spin recovery with the
engine out and stopped?

Not flown a Ventus M of any type but this looks like another
example of poor systems design. If the engine retraction sequence
consists of switching off ONE switch (e.g. DG808) or moving one
lever (Antares) then the pilot has nothing to do but control the
airspeed. Many of these other self launch/turbo retract systems
look like an invitation to "finger trouble".

I've heard dozens of stories of pilots outlanding their motor gliders when the engine wouldn't start, to discover on the ground that they'd forgotten to switch the fuel on.

At some point you have to ask - is this a pilot problem or a design problem?

There is a need for a fuel shut off valve. But it's a pilot problem if the pilot

A) Doesn't do a short engine run of say 30 seconds before leaving gliding distance of the home airport.

B) Chooses to close the fuel valve in flight unless there is a serious need to.

C) Chooses to pass on the opportunities to use and follow checklists.

At some point better design isn't going to save those who can't or won't take steps to protect themselves or who wait until they have run out of time by getting too low.

On Saturday, August 26, 2017 at 9:30:12 AM UTC-4, wrote:
...it's a pilot problem if...
At some point better design isn't going to save those who can't or
won't take steps to protect themselves or who wait until they have run
out of time by getting too low.

The rate of incidents and accidents clearly shows it is not just a pilot problem.
Perhaps better training and respect for the problem could help,
but reality of the pilot population and incident rate says its design problem...

On Saturday, August 26, 2017 at 8:23:08 AM UTC-4, wrote:
I've heard dozens of stories of pilots outlanding their motor gliders
when the engine wouldn't start, to discover on the ground that they'd
forgotten to switch the fuel on.

At some point you have to ask - is this a pilot problem or a design problem?

It is a design problem. A start checklist that seems quite trivial on the
ground becomes unmanageable when you're low, dehydrated, hot, stressed,
exhausted, trying to stay in save position for safe landing when the motor
doesn't start...

I worked with manufacturer and ILEC on this some years back.
The fuel shut-off is required for certification, even though
far more accidents have been caused by fuel valve in wrong position
than fire incidents (fire is why shut-off is required).
Work-around is fuel shut-off that normally remains "on", as is
done in ArcusM for example. That's not possible on some older
designs (for example, fuel can siphon through carb when motor
is in retracted position - don't ask me how I know).

Ergonomic design is not so easy!
The newer systems are MUCH better, but still leave room for screw-up...

wrote on 8/26/2017 5:23 AM:
On Saturday, August 26, 2017 at 12:15:08 PM UTC+2, Dave Walsh wrote:
Not flown a Ventus M of any type but this looks like another
example of poor systems design. If the engine retraction sequence
consists of switching off ONE switch (e.g. DG808) or moving one
lever (Antares) then the pilot has nothing to do but control the
airspeed. Many of these other self launch/turbo retract systems
look like an invitation to "finger trouble".

I've heard dozens of stories of pilots outlanding their motor gliders when the engine wouldn't start, to discover on the ground that they'd forgotten to switch the fuel on.

At some point you have to ask - is this a pilot problem or a design problem?

If the glider is a Schleicher self-launcher, it's a pilot problem. The valve
should be left open in flight. I leave mine open all the time on my ASH 26E, even
on the ground. It's main purpose is to keep fuel from getting to the engine if
there is a fire. The only time I shut it is during the annual, when it's tested.

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

maanantai 28. elokuuta 2017 5.36.30 UTC+3 Eric Greenwell kirjoitti:
If the glider is a Schleicher self-launcher, it's a pilot problem. The valve
should be left open in flight. I leave mine open all the time on my ASH 26E, even
on the ground. It's main purpose is to keep fuel from getting to the engine if
there is a fire. The only time I shut it is during the annual, when it's tested.


Maybe it should read "fuel emergency shutoff" with red knob, instead of "fuel valve", if that is the real use of it.