$1 billion BMS Ooops...

2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 8:30 PM:
On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.
I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..

I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

Hank Nixon.
--
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
And what was the glider?

Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH

--
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

Moshe Braner wrote on 3/7/2021 6:04 PM:
Personally I think that dragging an expensive battery pack along in every glider is inefficient
use of resources.* But then you may say the same about dragging equally, if not more, expensive
composite structures around the sky.* We do what we have to do to achieve our aerial dance
performances.* Then we land, and like any performance art, it's all gone poof, into the past.
We only do it because we love it.

I think having towplanes sit idle on the ground Monday through Friday is an inefficient use of
resources; ditto for tow planes sitting idle in poor weather, while I'm 100 miles away, looking
at growing cumulus.

But, I agree with the basic point that sharing the launch system is a more efficient use of
resources, and a way to do that with a self-launcher is a partnership, especially with partners
that have different or flexible schedules. Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor.

--
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

On 3/8/2021 8:41 AM, Eric Greenwell wrote:
Moshe Braner wrote on 3/7/2021 6:04 PM:
Personally I think that dragging an expensive battery pack along in
every glider is inefficient use of resources.Â* But then you may say
the same about dragging equally, if not more, expensive composite
structures around the sky.Â* We do what we have to do to achieve our
aerial dance performances.Â* Then we land, and like any performance
art, it's all gone poof, into the past. We only do it because we love it.

I think having towplanes sit idle on the ground Monday through Friday is
an inefficient use of resources; ditto for tow planes sitting idle in
poor weather, while I'm 100 miles away, looking at growing cumulus.

But, I agree with the basic point that sharing the launch system is a
more efficient use of resources, and a way to do that with a
self-launcher is a partnership, especially with partners that have
different or flexible schedules. Electric self-launchers seem
particularly well-suited to partnerships, with their easier use of the
motor.

If battery packs were standardized and removable (better for charging
anyway), then could also share them between gliders. Of course on the
day when the weather is really good everybody will be competing for the
use of the shared battery. Plug several shared standard batteries into
the electric winch on that day? ("Blue Sky" thinking here...)

On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 8:30 PM:
On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.
I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..

I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

Hank Nixon.
--
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
And what was the glider?

Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH
--
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

This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.

Tom

On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 8:30 PM:
On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.
I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..

I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

Hank Nixon.
--
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
And what was the glider?

Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH
--
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
This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.

Tom

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Tom

2G wrote on 3/8/2021 5:19 PM:
On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 8:30 PM:
On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.
I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..

I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

Hank Nixon.
--
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
And what was the glider?

Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH
--
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
This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.

Tom

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Some people like the challenge, much as glider pilots do in their flying (or they'd get an
airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the motor,
ESC, and batteries, and is now working out the motor mounting details.


--
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

I just gotta ask, "Why"?

What is the cost of the conversion? Is the engine failed and not
repairable? Are there a lot of brownie points for "saving the planet"?

If I wanted to, my gas powered Stemme could reach just about anywhere in
the western states on a single tank of gas. The electric offerings from
Stemme have great range at the expense of carrying a gas-powered
generator along to make the electric power to run the motor. Where's
the advantage?

Dan
5J

On 3/8/21 8:51 PM, Eric Greenwell wrote:
2G wrote on 3/8/2021 5:19 PM:
On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 8:30 PM:
On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
A hybrid system with a gas engine wouldn't have the pucker
factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid
engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an
imminent landing.
I'll wade in here with some experience. Top Flight, a Boston
startup specializing in hybrid propulsion systems, spend over
half a decade developing their power unit. The hardest part for
them was developing a unit which was reliable. Motors don't like
vibration and they don't like heat. Combine the two together and
the motor is not long for this world. It took a lot more R&D
than anyone expected to make a lightweight package which could
survive..

I would not expect anyone to be deploying this technology
anytime soon.. If and when it is commercialized, it will be
useful for ferry flights of electric aircraft. For any use which
requires permanent installation, you're probably better having
it drive the propeller directly.

eGliders, I sense a tone here which is reminiscent of
discussions about finally putting the 2-33 to rest. The US is no
longer the forefront of light aviation, so we need to look east
to see what the trends are. We know that leading glider
manufacturers are racing to bring eGliders to market.. A
gentleman who works on glider competition rules noted this
summer that glider records are falling left and right to
eGliders. There is a growing group of amateurs who are pulling
their engines out of their gas self-launchers and replacing them
with electric (If you'd like to be a part of this group, DM me).
The future was yesterday, but like any future it doesn't arrive
at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with
an electric.

Tom

Hank Nixon.
--
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

And what was the glider?

Hank has posted about the glider a number of times on RAS. Search
for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to
a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure
sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is
about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is
about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for
parts, not including items
required to do the airframe conversion and assuming the person doing
this can fabricate
required items, engineer and wire the system, design and construct
the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped
going through the learning
process. Of those I am aware of that have done ,or are doing this,
nobody has had that good
fortune.
FWIW
UH
--
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

This glider was converted from a sustainer to a self-launcher,
apparently to provide a capability it did not have before and not
because the engine did not perform as intended.

Tom

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Some people like the challenge, much as glider pilots do in their flying
(or they'd get an airplane): Ken Sebesta, a participant here, has
removed the self-launching gas motor from his AC-5 Russia and is
replacing it with an electric motor. I believe he's bench-tested the
motor, ESC, and batteries, and is now working out the motor mounting
details.

Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed 1 launch or 10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.

Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to 200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.

One launch and some modest assist capacity would be awesome and fit my primary goals:
- independent launch capability
- backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
- I'm ok with landing out on occasion if its safe and retrievable
- Really prefer electric over ICE

Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.

JJ

Dan Marotta wrote on 3/9/2021 7:42 AM:
I just gotta ask, "Why"?

What is the cost of the conversion?* Is the engine failed and not repairable? Are there a lot
of brownie points for "saving the planet"?

If I wanted to, my gas powered Stemme could reach just about anywhere in the western states on
a single tank of gas.* The electric offerings from Stemme have great range at the expense of
carrying a gas-powered generator along to make the electric power to run the motor.* Where's
the advantage?

Dan
Don't take it personally :^) Kenn is converting an AC-5 Russia, a WAY DIFFERENT glider than the
Stemme! It has a rattlely, unreliable motor of modest power, but I'll let Kenn fill in the details
of his decision.

On 3/8/21 8:51 PM, Eric Greenwell wrote:
2G wrote on 3/8/2021 5:19 PM:
On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
2G wrote on 3/7/2021 9:06 PM:
On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
...

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Some people like the challenge, much as glider pilots do in their flying (or they'd get an
airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the
motor, ESC, and batteries, and is now working out the motor mounting details.




--
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

If you are thinking of a motorglider as saving you from an unsafe landout, you are a Statistic - In -Waiting. What a motorglider does is save you the inconvenience of a safe landout and retrieve. If anything, it makes landouts more dangerous, as the pilot workload at a critical point increases (and this is an argument for electric, which typically takes less attention). A motorglider does not increase your range over unlandable terrain, or improve your chances for a safe landout (not reliably, anyway). Your example of continuous 7 - 9 knot sink for example, would be turned into continuous 5 - 7 knot sink with a typical sustainer, and it would take the most powerful of self launch power plants to turn that into a climb (even if you are lucky enough to have the motor start). A motor is no substitute for intelligent decisions, and it is not a substitute for having an easy glide angle to a safe landing site at all times. I have two friends with motorgliders left in trees that can bear witness.

Regarding who might replace an ICE with electric: I might be a candidate, if my engine were to fail in a way that required replacement. The $30K replacement cost and 6 months waiting time certainly would allow some contemplation. The glider already has doors, a prop, a boom, a jack to deploy the boom, capacity to carry around 150 lbs in a spacious engine bay. All that is left are the hard bits: motor, motor drive, and battery.

On Tuesday, March 9, 2021 at 10:36:11 AM UTC-8, John Johnson wrote:
Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed 1 launch or 10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.

Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to 200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.

One launch and some modest assist capacity would be awesome and fit my primary goals:
- independent launch capability
- backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
- I'm ok with landing out on occasion if its safe and retrievable
- Really prefer electric over ICE

Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.

JJ