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Best option for electric self starting glider



 
 
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  #31  
Old April 9th 20, 06:49 PM posted to rec.aviation.soaring
WB
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Posts: 236
Default Best option for electric self starting glider


https://evtol.com/news/lilium-evtol-catches-fire/


Paul Moller must be so proud! Founding Father of the whole VTOL scam industry. Moller is probably bummed that he didn't think of the electric angle. How many more of the gullible could he have scammed if he had glued a couple solar panels to the wings of his Skycar?
  #33  
Old April 9th 20, 07:20 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Default Best option for electric self starting glider

Magnus wrote on 4/8/2020 7:11 AM:
Hi experienced glider pilots,

I am a newly retired ex glider pilot that is updating my license and want to do some serious soaring and distance flights in Europe now that I have plenty of time. I live in Lausanne (member of Montricher gliding club) and as well member in Landskrona gliding club in Sweden as well where I spend most of my summers.
I have come down to the following alternatives for a private purchase:

- LAK 17C Front Electric Self starter, 18m, 22kW, 10.32 m2 wing surface, MTOW 600kg and CS-22 certification

- GP-15 Jetta, retractable motor, 15m, 25kW, 7.78 m2 wing surface, MTOW 470kg, UL/EcoLight certification

Both ships are flapped, take water ballast, Vne= 275km/h, wing loading between 37 - 57kg/m2, L/D around 50 and has a base price of apps. 100kEuro

GP15 seems to be a more modern glider with safety cockpit, ballistic rescue system and steerable tail wheel but LAK seems to be a more stable company with longer experience.

This is a nice problem to have but I would very much like your input as I have a one time opportunity to get my dream machine and I want to get it right.


Where do you find the information about the LAK 17C? I can not find any, not even
on the LAK site.

My dream is for a smaller, lighter, simpler self-launcher, but with the same
performance as my ASH26E. I considered the miniLak, AS34, and the GP15. The
miniLak did not have enough wing loading, L/D, and powered range for the
Nevada/Utah area I often fly in, and the AS34 was just as big and heavy as the
ASH26E. So, I have ordered a GP15 for delivery next year, as it promises the best
compromise. It will be a few months, maybe longer, before we know if it begins to
fulfill it's promise.

--
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
  #34  
Old April 9th 20, 08:16 PM posted to rec.aviation.soaring
[email protected]
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Posts: 34
Default Best option for electric self starting glider

On Thursday, April 9, 2020 at 7:30:05 AM UTC-7, Dave Walsh wrote:
Ha, ha; so nice to see so many optimists still exist in gliding.
The idea of a duplicate electric engine/battery system must
bring a smile to those existing realists who already own an
electric glider.
I suppose the thought that twin systems just doubles the
chance of failures has been noted? In the power world there
seems to be no obvious safety advantages in having two
engines. What do they say: "In a twin the remaining working
engine gate you safely to the accident site"....
Dave Walsh


Much of the problem with multi-engine safety is due to minimum control airspeed with one engine. This is less of an issue with in-line configurations, such as the Cessna Skymaster. One benefit of electric propulsion is that it's very compact and provides more mounting options. You'd never squeeze two rotax engines into an in-line configuration, but this would be very easy to do with electric.
  #35  
Old April 9th 20, 08:42 PM posted to rec.aviation.soaring
[email protected]
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Posts: 34
Default Best option for electric self starting glider

On Thursday, April 9, 2020 at 7:04:25 AM UTC-7, wrote:
On Thursday, April 9, 2020 at 2:57:10 AM UTC-4, kinsell wrote:
On 4/9/20 12:05 AM, wrote:

To quote Dave Nadler, "How hard could it be?"

Love the quote. Actually, this would be right up my alley. I've developed a few aircraft from scratch and people pay me a lot of money to modify special mission airplanes. A multi-motor self-launcher would be pretty easy to do as a modification to an existing self-launcher; probably a 3 month project. Perhaps I'll get around to this eventually, but first I have some more pressing items on my wish list!


Wow. The GP folks are about four years late in delivering product and
you can do all this in three months!! Go for it!!!

Actually the Alice electric plane has much of the redundancy that you're
asking for. Three motors with dual inverters on each of them, a highly
segmented battery configuration that can be reconfigured almost
infinitely. At least on paper it has those things, they burned up their
prototype before getting to taxi tests.


Clearly you are a brilliant developer.
I'll describe my experience with this task.
Start with existing self launch sailplane having a fuel to noise converter. ASW-24E
Procure a group of components from existing supplier that was/is being used by a developer of self launch sailplanes. 10 week delivery.
Engineer and implement modifications to incorporate "proven" components. 10 weeks part time.
Test
Component failure (drive).
Return for warranty repair 4 weeks.
Test
Component failure (drive).
Return for warranty repair 4 weeks.
Test
Component failure (drive).
Return for warranty repair. Manufacturer say they can't repair due to my modifications. There were none. 3 weeks.
Source alternative controller used in another proven glider. 3 weeks.
Integrate, develop control and instrumentation to replace items obsoleted by controller change and get running. 6 weeks.
Test fly. Multiple sessions.
Now flying but more work to do to get full power and functionality.
So far this has taken a bit over 2 years, admittedly not full time.
If there was am identified and proven set of compatible components it might be possible for a very skilled person or group to do fast track. Given that I have seen no such group, I seriously doubt the projection is even close to realistic.
Given time this will be made to work well, but it won't be fast, or cheap..
Been there- Doing that
UH


Great job. I'd be interested to hear which components you ended up using. I've had my eye on some of the Pipistrel stuff, but I haven't had a chance to play with them yet. What kind of performance are you getting out of your ASW-24E conversion?

I actually make a living doing these types of projects FAST. I'm fortunate to live above a 4,000ft^2 workshop with in-house machining, CNC routing, CAD, vacuum forming, welding, autoclave, paint booth etc. I reckon it would take me about 3 months of full time work (Note: I tend to spend at least 80 hours per week on such projects), but I completely understand that 1-3 years is probably more reasonable for a typical homebuilt project.

  #36  
Old April 9th 20, 08:44 PM posted to rec.aviation.soaring
[email protected]
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Posts: 34
Default Best option for electric self starting glider

On Thursday, April 9, 2020 at 12:31:56 AM UTC-7, wrote:
On Thursday, April 9, 2020 at 7:57:10 AM UTC+1, kinsell wrote:
On 4/9/20 12:05 AM, wrote:

To quote Dave Nadler, "How hard could it be?"

Love the quote. Actually, this would be right up my alley. I've developed a few aircraft from scratch and people pay me a lot of money to modify special mission airplanes. A multi-motor self-launcher would be pretty easy to do as a modification to an existing self-launcher; probably a 3 month project. Perhaps I'll get around to this eventually, but first I have some more pressing items on my wish list!


Wow. The GP folks are about four years late in delivering product and
you can do all this in three months!! Go for it!!!

Actually the Alice electric plane has much of the redundancy that you're
asking for. Three motors with dual inverters on each of them, a highly
segmented battery configuration that can be reconfigured almost
infinitely. At least on paper it has those things, they burned up their
prototype before getting to taxi tests.


If we're diving into pipedreams seeking maximum redundancy, what if there's a shared software bug between the parallel systems, like the firmware bug triggered by date that affected many GPS's simultaneously.
It'd be safer to combine two completely different systems for maximum redundancy, like Igor's MiniLAK FES-Jet (
https://imgur.com/a/Y6uK4fP)
Plus you get the benefit of both propeller for climb and jet for cruise.


Wow, that's a very cool concept. I wonder about the reliability and starting time of the jet.
  #37  
Old April 9th 20, 09:10 PM posted to rec.aviation.soaring
Dave Nadler
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Posts: 1,610
Default Best option for electric self starting glider

On Thursday, April 9, 2020 at 3:31:56 AM UTC-4, wrote:
...what if there's a shared software bug between the parallel systems,
like the firmware bug triggered by date that affected many GPS's simultaneously.


That wasn't a bug, epoch wrap was well understood and not implemented
by everyone. Especially in consumer stuff expected not to last 1 epoch.

It'd be safer to combine two completely different systems for maximum
redundancy, like Igor's MiniLAK FES-Jet (https://imgur.com/a/Y6uK4fP)


Pretty much guaranteeing something will always be broken,
and doubling the expertise required to diagnose and fix...
  #38  
Old April 9th 20, 09:32 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 4,601
Default Best option for electric self starting glider

I'm not familiar with that airport, but my Stemme has 115 turbocharged
horsepower and a reliable Rotax 4-stroke engine.Â* It climbs at 800 fpm
at high density altitudes and, with a full gas tank of 30 US gallons,
can cruise for 8 hours at over 100 kts at 18,000' (more if you want to
be cold).

Or are we just talking about single seaters with delightfully light
controls? :-D

On 4/8/2020 10:23 PM, Tango Whisky wrote:
Magnus, with a LAK17C you won't be able to take off safely from Montricher, especially not to the northeast. I wouldn't go for less than 50 hp, and that leaves you with Ventus 2CM, DG800, Antares 20E or ASH26E with the Schleicher prop.

Bert
Ventus cM "TW"
working in Lausanne, flying in Bex


--
Dan, 5J
  #39  
Old April 9th 20, 09:38 PM posted to rec.aviation.soaring
kinsell
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Posts: 546
Default Best option for electric self starting glider

On 4/9/20 12:20 PM, Eric Greenwell wrote:
Magnus wrote on 4/8/2020 7:11 AM:
Hi experienced glider pilots,

I am a newly retired ex glider pilot that is updating my license and
want to do some serious soaring and distance flights in Europe now
that I have plenty of time. I live in Lausanne (member of Montricher
gliding club) and as well member in Landskrona gliding club in Sweden
as well where I spend most of my summers.
I have come down to the following alternatives for a private purchase:

- LAK 17C Front Electric Self starter, 18m, 22kW, 10.32 m2 wing
surface, MTOW 600kg and CS-22 certification

- GP-15 Jetta, retractable motor, 15m, 25kW, 7.78 m2 wing surface,
MTOW 470kg, UL/EcoLight certification

Both ships are flapped, take water ballast, Vne= 275km/h, wing loading
between 37 - 57kg/m2, L/D around 50 and has a base price of apps.
100kEuro

GP15 seems to be a more modern glider with safety cockpit, ballistic
rescue system and steerable tail wheel but LAK seems to be a more
stable company with longer experience.

This is a nice problem to have but I would very much like your input
as I have a one time opportunity to get my dream machine and I want to
get it right.


Where do you find the information about the LAK 17C? I can not find any,
not even on the LAK site.

My dream is for a smaller, lighter, simpler self-launcher, but with the
same performance as my ASH26E. I considered the miniLak, AS34, and the
GP15. The miniLak did not have enough wing loading, L/D, and powered
range for the Nevada/Utah area I often fly in, and the AS34 was just as
big and heavy as the ASH26E. So, I have ordered a GP15 for delivery next
year, as it promises the best compromise. It will be a few months, maybe
longer, before we know if it begins to fulfill it's promise.


Typing "lak 17c" into Google brings up multiple results, including an
Oct 2018 test flight in FB. Also been discussed on R.A.S.
  #40  
Old April 9th 20, 10:37 PM posted to rec.aviation.soaring
son_of_flubber
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Posts: 1,550
Default Best option for electric self starting glider

On Thursday, April 9, 2020 at 3:16:58 PM UTC-4, wrote:

Much of the problem with multi-engine safety is due to minimum control airspeed with one engine. This is less of an issue with in-line configurations, such as the Cessna Skymaster. One benefit of electric propulsion is that it's very compact and provides more mounting options. You'd never squeeze two rotax engines into an in-line configuration, but this would be very easy to do with electric.


I'd not much worry about the FES electric motor or prop failing. I might get a big reliability boost from redundant controllers. A small secondary battery pack with ~10 minutes of sustainer function would reduce my chances of landing in someone's attic. A more reliable 'metering fuel gauge' would solve the same problem with fewer parts.

If the system fails, the best Plan B for me is to land out. As a recreational pilot I choose where to fly, so flying out of reach of a landable field would be simple hubris.

Owning a tow-capable LSA AND a pure sailplane seems the most cost-effective solution to a shortage of aerotow providers. Finding a time-building young tow pilot should not be too hard, especially if I let them use the plane for few hours gratis and they might even crew if I occasionally land out. And I could fly the LSA on poor soaring days.

My interdependence with a group of people is one of the most rewarding aspects of soaring. If I wanted to be entirely self-reliant, I would buy a power plane, and pay hourly for professional assistance as needed.

 




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