$1 billion BMS Ooops...

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.

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).

On Thursday, 11 March 2021 at 01:33:34 UTC, Matthew Scutter wrote:
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).

On grid - but of course we have a lot of draw for other purposes before people start charging gliders.

waremark wrote on 3/10/2021 4:42 PM:
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.

How long a self-retrieve distance is the minimum acceptable to you?

--
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

Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by
a distance of 350 nautical miles? That's what I'll be doing in June to
relocate the Stemme from Moriarty, NM to Rifle, CO. And it might use
half a tank of gas.

Of course, I'll only do it that way if soaring conditions don't support
gliding the whole way.

Dan
5J

On 3/11/21 6:18 PM, Eric Greenwell wrote:


How long a self-retrieve distance is the minimum acceptable to you?

Dan Marotta wrote on 3/12/2021 10:30 AM:
Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
nautical miles?* That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
Rifle, CO.* And it might use half a tank of gas.

Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.

Dan
5J

On 3/11/21 6:18 PM, Eric Greenwell wrote:


How long a self-retrieve distance is the minimum acceptable to you?

Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )

But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
enough retrieve distance, and some think 50 miles is plenty. These are the people that are
willing to drive from where they live to where they want to fly. I'm one of those people,
because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
in it.

On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
Dan Marotta wrote on 3/12/2021 10:30 AM:
Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
Rifle, CO. And it might use half a tank of gas.

Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.

Dan
5J

On 3/11/21 6:18 PM, Eric Greenwell wrote:


How long a self-retrieve distance is the minimum acceptable to you?

Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )

But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
enough retrieve distance, and some think 50 miles is plenty. These are the people that are
willing to drive from where they live to where they want to fly. I'm one of those people,
because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
in it.

Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).

Tom