$1 billion BMS Ooops...

I don't take anything on RAS personally any more. I was genuinely
interested in the "why" aspect of the conversion.

Dan
5J

On 3/9/21 12:25 PM, Eric Greenwell wrote:

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

What is the cost of the conversion?Â* 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.Â* 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.Â* 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.

On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
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.

Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
I'd also mention out there's a large difference between 'safe' LO sites. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.

JJ

One thing a motorglider allows you to do is to select safer landout sites - not because you can motor away from a bad one, but because retreating towards a safer area, while still high, has less risk of inconvenience. A fair number of landouts in bad places can be attributed to wanting to get closer to home to have the retrieve be shorter, passing up better - but further away - choices. We had two landouts in a lake last year which probably had this as a component in the decision making. With the possibility of a motor start, retreating towards a nice safe paved runway does not have the same consequences for the rest of the evening.

When you are thinking about that final glide in sink, remember that pulling the motor out to start it will cost you a few hundred feet in altitude, even if it fails and you are able to put it away again. If it fails and you are unable to put it away, you've just given up about 1/2 your glider performance. On my glider the difference is 50:1 going to 20:1. The jets are a bit better and an FES better still, but there is still consequence, even if it is just a distraction from efficient flying. This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it.. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.

On Tuesday, March 9, 2021 at 3:53:52 PM UTC-8, John Johnson wrote:
On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
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.

Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
I'd also mention out there's a large difference between 'safe' LO sites. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.

JJ

On Tuesday, March 9, 2021 at 7:01:56 PM UTC-7, jfitch wrote:
This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.

Good points. I can see where a 'backup' motor sounds great on the surface, but in practice its whole 'nother set of complex decisions and uncertain risk tradeoffs. More so than I was considering.
Continuing to benefit from this thread - thanks.
JJ

On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
One thing a motorglider allows you to do is to select safer landout sites - not because you can motor away from a bad one, but because retreating towards a safer area, while still high, has less risk of inconvenience. A fair number of landouts in bad places can be attributed to wanting to get closer to home to have the retrieve be shorter, passing up better - but further away - choices. We had two landouts in a lake last year which probably had this as a component in the decision making. With the possibility of a motor start, retreating towards a nice safe paved runway does not have the same consequences for the rest of the evening.

When you are thinking about that final glide in sink, remember that pulling the motor out to start it will cost you a few hundred feet in altitude, even if it fails and you are able to put it away again. If it fails and you are unable to put it away, you've just given up about 1/2 your glider performance. On my glider the difference is 50:1 going to 20:1. The jets are a bit better and an FES better still, but there is still consequence, even if it is just a distraction from efficient flying. This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.
On Tuesday, March 9, 2021 at 3:53:52 PM UTC-8, John Johnson wrote:
On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
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.

Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
I'd also mention out there's a large difference between 'safe' LO sites.. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.

JJ

A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

Yep. There is a decision altitude below which the engine is no option anymore.

Le mercredi 10 mars 2021 Ã* 10:38:28 UTC+1, a écritÂ*:
On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
JJ
A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

What actions did you take to get out of the sustained sink? Having owned and flown pure gliders, sustainers, and motor gliders I can attest that an engine is not a substitute for xc skills. If you want a
sustainer, imagine flying the flights you have flown with half a load of water that you cannot dump. Every time the engine starts should be a surprise, because
if it doesn't start you now have effectively full open and locked airbrakes.. I fly an engined glider just like the engine is not going to start. Twice I have landed out without even attempting the engine as I have a hard deck
where below I will not be stupid.
Jon



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

When considering outlanding options and engines, consider flying west
from Taos, NM:


Dan
5J

On 3/10/21 6:08 AM, Tango Whisky wrote:
Yep. There is a decision altitude below which the engine is no option anymore.

Le mercredi 10 mars 2021 Ã* 10:38:28 UTC+1, a écritÂ*:
On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
JJ
A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

Someone said:

"Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor."

The contrary may be the case for electric gliders with removable batteries. At our airfield the electricity supply will not be adequate for the potential recharging requirements of more electric gliders. At the moment the only FES gliders at the club are individually owned, and the owners take the batteries home to charge them. The batteries of a syndicate owned glider would have to be charged on site - which will become a problem.

On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve. I have rarely needed it, but if I didn't I would need to make road retrieve arrangements before cross country flights. I won't change to an electric glider until it has that sort of endurance - which is unlikely in my gliding lifetime.

Incidentally, twice in the 14 years I have landed in a field (safely, I am happy to say). The first time I initiated the start sequence at 1,000 foot on downwind, and the engine failed to start. The second time, I was on a marginal final glide, I took a clear decision to continue below a safe engine start height in the knowledge that there were safe fields on the way to the airfield, and when the final glide became too marginal I landed in a field without considering deploying the engine. Happily, I have never had to start the engine other than over a safe place to land.

On Thursday, March 11, 2021 at 10:42:32 AM UTC+10, waremark wrote:
Someone said:

"Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor."

The contrary may be the case for electric gliders with removable batteries. At our airfield the electricity supply will not be adequate for the potential recharging requirements of more electric gliders. At the moment the only FES gliders at the club are individually owned, and the owners take the batteries home to charge them. The batteries of a syndicate owned glider would have to be charged on site - which will become a problem.

On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve. I have rarely needed it, but if I didn't I would need to make road retrieve arrangements before cross country flights. I won't change to an electric glider until it has that sort of endurance - which is unlikely in my gliding lifetime.

Incidentally, twice in the 14 years I have landed in a field (safely, I am happy to say). The first time I initiated the start sequence at 1,000 foot on downwind, and the engine failed to start. The second time, I was on a marginal final glide, I took a clear decision to continue below a safe engine start height in the knowledge that there were safe fields on the way to the airfield, and when the final glide became too marginal I landed in a field without considering deploying the engine. Happily, I have never had to start the engine other than over a safe place to land.

Is your airfield off-grid? How constrained is the capacity of your club's electricity connection that you wouldn't be able to handle charging gliders there? The FES chargers are 1200W, the Antares is similar. They seem to only charge at full current briefly and then start dropping down rapidly as the batteries approach full charge. Even with a single phase connection you should be fine for 12 gliders at max current simultaneously. I even charge my FES batteries off an inverter in my van (which has 2x135Ah Lithiums + 300W solar + 1000W inverter).