
New electric engine improves safety of light aircraft - mhb
http://portal.uc3m.es/portal/page/portal/actualidad_cientifica/noticias/safety_aircraft
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Already__Taken
Why wouldn't you want to rip out your starter motor, alternator and normal
battery to replace them with this? Get some wins back with regards to weight
and cabin space. I'm assuming some steady use would help keep the battery in
good condition as well as ensuring it's tested and ready to go by definition.

This being an emergency only thing how does it last? If it needs a new £5000
battery every 5 years just to sit there in case I can imagine many pilots just
not being able to justify it. Given the target market.

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mmaunder
At the risk of stating the obvious, many crashes would not be affected by
this:

CFIT (controlled flight into terrain). Sadly common, it's how Kennedy junior
died and many others.

Stall/spin. Common on take off and landing and avoidance is a huge emphasis in
training.

Visual flight into instrument conditions. If untrained what often happens is
the pilot will end up in a spin/spiral into the ground or doing a CFIT.

Also, running out of gas or engine failure requires the pilot to activate the
backup correctly. Sounds silly, but I recall a pilot crossing the english
channel with her family and forgetting to switch fuel tanks which caused a
crash. Human factors is a huge part of training - so for this to be effective
it needs to be drilled into the pilot's checklist on engine failure. Also this
is time taken away from finding an emergency landing field and trying to
restart the primary engine.

I'd say an interesting comparison is the Cirrus SR20/22 which has a parachute
for the plane. It gives you a great sense of security but that particular
plane is the new "doctor killer" (a name given to the V-Tail Bonanza in the
past).

Curious to see how this will be seen and used by industry.

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lujim
That seems like a bit of an pessimistic take on this. Isn't that like saying
front impact airbags aren't very helpful in a rear end collision?

CFIT, stall/spin, and VFR into instrument conditions are all training
deficiencies. This solution fixes something a pilot can't be trained to avoid,
an engine failure at an inopportune time. Training can only take you as far as
"glide and crash gracefully" without stalling and spinning.

Also this could easily be made to automatically activate. Many multi engine
aircraft will automatically increase power on the good engine by a few percent
after an engine failure.

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repiret
Most general aviation engine failures are caused by poor fuel management.
Training and discipline helps just as much with fuel management.

While there are clearly situations where this device can save lives, I agree
with the GP that the case needs to be made that its worth the cost and weight,
and that the people peddling it haven't made that case.

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lujim
I don't think of it as someone 'peddling' something. To me it seems like a
creative solution to an actual problem.

Training is the best, but private pilots vary drastically in their training,
skill, experience level (especially recent experience).

While I would love to see all pilots selected out of the population for their
aptitude, then go through years of intense military like training followed by
checkrides every 6 months, it's just not realistic in General Aviation. It's a
group of people that differ wildly in their aptitude, age, skill level, that
just happen to be healthy enough to pass a relatively low bar medical exam.

Training for Private Pilots in the US might not be perfect, but I don't think
a "throw training at it" response is all that useful of an answer. Train what?
For how many hours, and require recency of experience after how long?

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unics
Wonderful idea. I do wonder how that changes the center of gravity and how
much weight is diminished for cargo but seems well worth it. When the engine
goes out you generally only have 10 seconds to decide where to land. Now it
seems you have many minutes to find a place. In most circumstances I'd think
this is better then the parachutes for planes because you have a chance to
save very expensive airplanes.

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markab21
I agree that this is better than parachutes , but not because of the cost of
the plane. If your engine is failing, your plane failed you and isn't worth
saving. that's what insurance is for : ) the moment you pull a parachute (for
example the CAPS on the cirrus , the plane is totaled anyway).

The most dangerous place to have a failure is during initial take off (low
hour student pilot here). The engine kicking on would give you a chance to
actually do what is nearly impossible in this circumstance, get back to the
airport safely without a stall.

As I understand usually the most dangerous circumstances are the one above
described, stalling on base or final approach to runway and flying from VFR
(clear of clouds with visibility) into IMC poor weather conditions.

Both of those circumstances wouldn't benefit from a backup engine. : (

As other people in the threads have posted, Fuel Starvation, water
condensation in the fuel, some of those situations this would definitely help,
but all of those conditions are 100% preventable with proper pre-flight
planning and inspections.

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ju-st
Commercial airplanes have (at least) two engines because of the high risk of
failure at take-off.

The next step for this electric engine would be to replace that second heavy,
expensive engine every large airplane carries around...

Additionally, the full power of the two engines is only needed at takeoff. At
cruise they only run at 30-40%. An electric motor with a relativly small
battery would be enough to provide enough power at takeoff.

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phillc73
Plenty of "commercial" aeroplanes only have one engine. The Cessna Caravan
springs to mind. I run a couple of Cessna 206s for joy flights. Strictly
speaking, people pay my company money for this, therefore the aircraft are
"commercial."

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snarfy
Why would there be a problem with the main engine? It seems like you should
fix/redesign/etc that instead of adding another engine.

It reminds me of code that catches all exceptions instead of fixing the
problem so those exceptions can never happen.

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phlo
Systems with moving parts undergo lots of stress. At some point, they will
fail. Regular maintenance limits this; and the maintenance prescribed even for
light aircraft keeps it to a minimum.

Still, no system is ever 100% reliable. The typical safeguard for engine
failure in light aicraft is to glide to a safe landing. Starting with basic
training, you'll do so repeatedly (starting from the vicinity of a landing
strip, of course) and should be able to bring a plane down safely. Some (very)
light planes even include a parachute system that'll bring down the plane in a
manner safe for its occupants.

Speaking as a private pilot with little experience, this systems seems
promising to me in two respects: In the case of a failed engine, it'll take
you another 20 km or so. This can make the difference between a survivable
landing in a field somewhere and a completely safe landing on the closest
airstrip. Additionally, you get 40 hp or so of available power in situations
where you need it, like taking off or going around after a botched landing.
This could allow for shorter runways and help speed your initial climb, which
is generally considered one of the most dangerous phases of flight: At that
point you are both flying slow and low, and both speed and altitude are
important safety aids. After a cursory first look, this system appears to be a
considerable improvement in safety while avoiding much of the complexities a
true twin engine system would entail.

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scrumper
> After a cursory first look, this system appears to be a considerable
> improvement in safety while avoiding much of the complexities a true twin
> engine system would entail.

Right. It's a sort of asymmetric thrust, coaxial twin. Very unusual, and
clever too.

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mrfusion
Dumb question, could this combined with the power from the regular engine give
you thrust greater than the weight of your plane and potentially allow
vertical take off and landing (imagine the nose pointed up, And obviously
you'd need special landing legs, etc)

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knodi123
There are no dumb questions, but if you were a pilot, this would certainly be
a dumb thing to try.

1\. in light planes, "the weight of the plane" is a little more complicated,
since fuel can increase the weight of your plane by, like, 40% or so. We're
talking, like, 500 pounds of fuel on a 1600 pound plane.

2\. a helicopter has a very complex mechanism to give it control based on
propellor movement. an airplane trying to hover without these mechanisms would
be essentially uncontrolled. it would almost certainly spin like a top.

3\. this specific electric boost engine claims to add 40 horsepower. a cessna
172 has 180 horsepower. So, not a shocking improvement.

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mrfusion
Thanks, makes sense for this case. I'm still wondering though, say for a
purely electric plane designed for this type of VTOL from the ground up, is it
workable?

Couldn't the large area of the wings counteract the counter rotation or at
decrease it to an acceptable level?

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knodi123
> say for a purely electric plane designed for this type of VTOL from the
> ground up, is it workable

Sure, toys can do it. That's what all these commercial drones are doing. But
there's an irritating inverse square law that says the power required to hover
goes up shockingly fast when you start to increase the weight.

Also, there's a reason commercial airlines don't use electric engines and
batteries; the power-to-weight ratio for a gasoline engine far exceeds that of
an electric+battery solution.

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guscost
Honestly I still don't fully accept that having a second engine running on
completely different fuel is a good idea for a _car_. A hybrid _airplane_
seems too ridiculous to even consider, because now both engines have to be
lifted up into the sky!

But of course this is based on my own amateur and dated knowledge. With all
the work that has gone into hybrids lately, who knows.

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clueless123
I am not sure how practical is this idea. Just thinking of the extra weight,
extra maintenance, extra complexities, extra costs. For my money, I much
rather have good training and a ballistic parachute installed.

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mrfusion
I wonder if you could use your propeller as a "wind turbine" when landing to
recapture some energy? Of fly around in thermals and charge your battery??

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exDM69
> I wonder if you could use your propeller as a "wind turbine" when landing to
> recapture some energy?

Helicopters do this, it's called autorotation. They spin up the rotor while
descending and then trade the rotational momentum for a little bit of lift to
make a safe landing. It's a tricky maneuver but a part of every heli pilot's
training.

I doubt that it's a viable strategy for light aircraft, though. The loss of
airspeed from extracting energy out of the wind stream is more dangerous than
gliding. Thermals aren't powerful enough to keep a non-glider aircraft in
flight as far as I know.

Large aircraft use a small windmill or a ram air turbine to keep hydraulics
and electrics up in case of a loss of power, though.

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mikeash
Small aircraft can definitely thermal. It would require powerful and big
thermals compared to what a glider needs, but such conditions do exist. A
small Cessna probably has a minimum sink speed in the neighborhood of 700fpm,
and thermals stronger than that do exist, and are pretty common in some
places.

The problem, of course, is that it's just not reliable enough to count on.

