FES vs Gas Engine – Finding a Thermal?

sunnuntai 27. elokuuta 2017 0.08.34 UTC+3 Dave Nadler kirjoitti:
On Saturday, August 26, 2017 at 12:43:51 PM UTC-4, wrote:
Not the answer for everybody, but try a jet!

I think all of my buddies with jet (JS) have had at least one failure.
None of these contraptions is 100% or even close.
Plan A is always landing.
If it starts, be delighted.
WHEN it DOES NOT start, just finish the landing.

Be safe out there,
Best Regards, Dave

I've heard also that starting a jet (also JS) is far from foolproof. Apparently you have to sit trough whole start-abort-cycle and attempting restart takes very long time.

my experience has been that the vibration (and possibly disturbed airflow) caused so much wild gyration in the vario readings that it seemed pointless to try to determine if I was flying into rising air, so I just climbed first, then shut down the engine and started a thermal search.

Hi Frank,
My ApisM is equipped with a pneumatic toggle switch that disables the rear-fin-mounted Total Energy probe. It is vital that you have this. It completely eliminates the wild vario readings so that you can detect thermals and circle in them with the engine on. This greatly boosts your climb rate and you get to shut off the engine much quicker. When the engine is retracted just flip the switch and you are back to TE mode.

At the 18 meter Nationals in Uvalde this month one would imagine there were multiple in air-starts. The only one I had heard of that did not start was the jet on a Jonkers. Having owned several lawn mower sustainers, I wonder if it is feasible for a sustainer electric pylon, or would the weight be effectively the same as a self launch?

On Sunday, August 27, 2017 at 12:38:53 AM UTC-7, krasw wrote:
sunnuntai 27. elokuuta 2017 0.08.34 UTC+3 Dave Nadler kirjoitti:
On Saturday, August 26, 2017 at 12:43:51 PM UTC-4, wrote:
Not the answer for everybody, but try a jet!

I think all of my buddies with jet (JS) have had at least one failure.
None of these contraptions is 100% or even close.
Plan A is always landing.
If it starts, be delighted.
WHEN it DOES NOT start, just finish the landing.

Be safe out there,
Best Regards, Dave

I've heard also that starting a jet (also JS) is far from foolproof. Apparently you have to sit trough whole start-abort-cycle and attempting restart takes very long time.

Jonathan St. Cloud wrote on 8/27/2017 2:58 PM:
At the 18 meter Nationals in Uvalde this month one would imagine there were multiple in air-starts. The only one I had heard of that did not start was the jet on a Jonkers. Having owned several lawn mower sustainers, I wonder if it is feasible for a sustainer electric pylon, or would the weight be effectively the same as a self launch?

Schleicher provides the ASG 32 EL, an electric sustainer version of the ASG 32.


--
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

On Sunday, August 27, 2017 at 5:58:39 PM UTC-4, Jonathan St. Cloud wrote:
...I wonder if it is feasible for a sustainer electric pylon, or would
the weight be effectively the same as a self launch?

A huge % of the weight of electric is in the battery.
As the electric motor is relatively light, might as well do self-launch...

Dave Nadler wrote on 8/25/2017 7:29 AM:
On Friday, August 25, 2017 at 10:15:06 AM UTC-4, Dave Walsh wrote:
Dave N: Be interesting to know what on earth "plummet
mode" is in the Arcus M?

Plummet-mode is when engine is extended and not running.
Not exciting in Antares or FES, a bit more so with turbos.
Exciting in gas-powered pylon self-launchers (engine/radiator drag).
ArcusM is not too bad - about 500fpm.
Some motorgliders are more like 800fpm which definitely focuses one's attention.

Planning for plummet-mode is especially important for safety during:
- departure route
- powered flight between landable areas
- shut-down activities
These engines have a very high failure rate and its truly exciting to have
a failure on departure - you better have your response planned in advance.
Power-plant retraction is also failure-prone, so advance planning about
when to give up and restart or land is advisable...

Fortunately for Schleicher self-launchers, the "plummet mode" Dave describes does
not exist. Glide ratio for my ASH 26 E is about 20:1 in the pattern with the pylon
up and gear down. It feels like I'm flying Blanik - nothing to worry about, and
the practical effect of landing with the pylon up means I use somewhat less
spoiler than with the mast retracted. Gliders with the "engine on a stick", like
PIK 20E, are strongly affected when the pylon is up.

--
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

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.

On Thursday, August 24, 2017 at 4:29:01 PM UTC-4, V1 wrote:
While reading the FES article in June Soaring (yes, I’m behind in my reading), I noticed the author’s comment about searching for a thermal while FES was running, then shutting down FES as he started to climb. This is a topic I don’t recall seeing discussed in any FES vs gas comparisons.

In my Solo-powered Ventus 2cxT, my experience has been that the vibration (and possibly disturbed airflow) caused so much wild gyration in the vario readings that it seemed pointless to try to determine if I was flying into rising air, so I just climbed first, then shut down the engine and started a thermal search.

My question – do others have experience to share about their ability to find thermals while a sustainer or self-launcher (either gas or electric) was running? If electric has an advantage here, this could reduce the run-time needed and conserve “fuel�.

- Frank

On the PIK I have a standard TE probe going to
a gust filter and then the Winter vario.

This is good enougt with the engine running
to evaluate a thermal.

JMF

On Sunday, August 27, 2017 at 5:58:39 PM UTC-4, Jonathan St. Cloud wrote:
At the 18 meter Nationals in Uvalde this month one would imagine there were multiple in air-starts. The only one I had heard of that did not start was the jet on a Jonkers. Having owned several lawn mower sustainers, I wonder if it is feasible for a sustainer electric pylon, or would the weight be effectively the same as a self launch?

I'm working on conversion of ASW-24E from Rotax shaker to pylon mounted electric as I write this. Weight change will be about 8 lb and CG move forward..
UH