FES underpowered for 18m ship?

On Monday, September 14, 2020 at 2:58:08 PM UTC-4, Mana wrote:
It would be disappointing if when you fly “by the rules� and remain above
a landing / outlanding spot until you turn power on, that the FES doesn’t
allow to regain altitude, but only to maintain level flight.
It changes the flight planning strategy altogether.

And it will be dangerous and fool-hardy if you DO NOT always:
- keep a landing spot in easy reach, and
- never engage power until the landing is planned in you're in position.

To quote a recent email I received from LBA/EASA:

....please let us point out that the pilot of a powered glider
shall always have in mind, that it might be necessary to operate
his aircraft as a pure glider. The engine of a powered glider,
predefined by airworthiness requirements JAR/CS-22, does not
meet the same safety standards as a "Part-E" engine of a motorplane.

The flight training for powered gliders shall take into account, that
loss of engine power may occur anytime, and result in a scenario, which is
comparable to a cable break during a winch launch or an aerotow.
This deviation to the operation of a motorplane is reflected in several
paragraphs of the airworthiness requirements JAR/CS-22, applicable for a
powered glider. Examples are the specifications for engines, used for
powered gliders (JAR/CS-22 Subpart H) that are less stringent than those
for powered aircraft (CS-23). Moreover, requirements for software are
not mentioned in the JAR/CS-22 at all - contrary to the specification
for large aeroplanes (CS-25).

On 9/14/20 1:31 PM, Dave Nadler wrote:
On Monday, September 14, 2020 at 2:58:08 PM UTC-4, Mana wrote:
It would be disappointing if when you fly “by the rules� and remain above
a landing / outlanding spot until you turn power on, that the FES doesn’t
allow to regain altitude, but only to maintain level flight.
It changes the flight planning strategy altogether.

And it will be dangerous and fool-hardy if you DO NOT always:
- keep a landing spot in easy reach, and
- never engage power until the landing is planned in you're in position.

To quote a recent email I received from LBA/EASA:

...please let us point out that the pilot of a powered glider
shall always have in mind, that it might be necessary to operate
his aircraft as a pure glider. The engine of a powered glider,
predefined by airworthiness requirements JAR/CS-22, does not
meet the same safety standards as a "Part-E" engine of a motorplane.

The flight training for powered gliders shall take into account, that
loss of engine power may occur anytime, and result in a scenario, which is
comparable to a cable break during a winch launch or an aerotow.
This deviation to the operation of a motorplane is reflected in several
paragraphs of the airworthiness requirements JAR/CS-22, applicable for a
powered glider. Examples are the specifications for engines, used for
powered gliders (JAR/CS-22 Subpart H) that are less stringent than those
for powered aircraft (CS-23). Moreover, requirements for software are
not mentioned in the JAR/CS-22 at all - contrary to the specification
for large aeroplanes (CS-25).


Nice words, but I'm sure many FES pilots aren't going to heed them. If
they think the system is safer, they'll just push the limits that much
further.

From the mini-Lak brochure on lak.it:
"The FES propulsion system has no known reports of in-flight failures,
allowing you to stay confident in areas of no-lift."

We've seen the same mentality displayed in some of the Jeta discussions,
which has a more complex system.

On Monday, September 14, 2020 at 9:32:04 PM UTC-4, kinsell wrote:
From the mini-Lak brochure on lak.it:
"The FES propulsion system has no known reports of in-flight failures,
allowing you to stay confident in areas of no-lift."

That's just Nonsense. I know of an instance where the controller failed while
FES was under power and the engine quit. I hardly hear about all problems,
surely there have been others...

On 9/15/20 6:38 AM, Dave Nadler wrote:
On Monday, September 14, 2020 at 9:32:04 PM UTC-4, kinsell wrote:
From the mini-Lak brochure on lak.it:
"The FES propulsion system has no known reports of in-flight failures,
allowing you to stay confident in areas of no-lift."

That's just Nonsense. I know of an instance where the controller failed while
FES was under power and the engine quit. I hardly hear about all problems,
surely there have been others...


Of course it's nonsense, but if you tell people exactly what they want
to hear, they gobble it up. Red meat for the base.

The Silent 2 that went through the roof in Connecticut made quite a
splash, I'd call that an inflight failure. Apparently if a battery
explodes on landing roll, that doesn't count as "in flight".

People say motors have been around forever, that's true. But inverters
that take high-voltage DC, convert it to three-phase power at over 25KW
using transistors, and doing it with limited space and cooling, well
that's not something you run down to Grainger to pick up.

I'm not familiar with the FES accident referenced by the OP, would like
more data on that.

-Dave