Future of aviation, or flash in the pan??

On Tuesday, January 28, 2020 at 1:48:48 AM UTC-5, jfitch wrote:
On Monday, January 27, 2020 at 7:04:36 PM UTC-8, Dave Nadler wrote:
On Sunday, January 26, 2020 at 7:14:12 PM UTC-5, jfitch wrote:
...an electric retrofit for the AS self launchers.
The engineering and installation should be relatively simple.

Um, not on this planet.

Perhaps you did not catch the "relatively"? Engine bay is already there, the doors are there, it is engineered and built for the weight, the extraction mechanism is already there, even the prop and boom. So yes, "relatively simple" compared to retrofitting say an ASW27, which is being done, and has none of those things.

I am not a stranger to complexity, or aircraft design.

"How hard could it be"
That depends.
Certainly if you already have an engine bay, and lift mechanism, you have a great start. No engineering the hole in the fuselage, etc.
If you have a proven drive system, much of the next part is more easily accomplished.
2 meaningful issues with converting the later Schleicher ships:
1) Where do the batteries go? Engine bay has some room but CG possibilities become limited. Wing installation would most certainly involve major stuff in any of the hard tank wings. Support and service access are non trivial.
This is the major task on the '34. The rest is mostly transplanting proven motor and drive into the '34 from the 32E.
2) Engine bay size matters because it limits available prop diameter and this is a real issue in getting performance out of the drive.

I have some practical experience with this as I am now starting test flying of an ASW-24E that has been converted to electric.

How hard could it be?

The largest barrier is a lack of proven motor/ controller systems to incorporate into a project.
FWIW
UH

wrote on 1/28/2020 6:59 AM:
Perhaps you did not catch the "relatively"? Engine bay is already there, the
doors are there, it is engineered and built for the weight, the extraction
mechanism is already there, even the prop and boom. So yes, "relatively
simple" compared to retrofitting say an ASW27, which is being done, and has
none of those things.

I am not a stranger to complexity, or aircraft design.
"How hard could it be" That depends. Certainly if you already have an engine
bay, and lift mechanism, you have a great start. No engineering the hole in the
fuselage, etc. If you have a proven drive system, much of the next part is more
easily accomplished. 2 meaningful issues with converting the later Schleicher
ships: 1) Where do the batteries go? Engine bay has some room but CG
possibilities become limited. Wing installation would most certainly involve
major stuff in any of the hard tank wings. Support and service access are non
trivial. This is the major task on the '34. The rest is mostly transplanting
proven motor and drive into the '34 from the 32E. 2) Engine bay size matters
because it limits available prop diameter and this is a real issue in getting
performance out of the drive.

There is a significant size compartment between the engine bay and gear wheel that
could hold batteries, and more space in the gear well that has the 16 liter fuel
tank. Some batteries can be placed in the engine bay, as an electric motor is
lighter than the Wankel and all it's accessories (starter, muffler, oil tank, etc).

--
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 Tuesday, January 28, 2020 at 6:59:56 AM UTC-8, wrote:
On Tuesday, January 28, 2020 at 1:48:48 AM UTC-5, jfitch wrote:
On Monday, January 27, 2020 at 7:04:36 PM UTC-8, Dave Nadler wrote:
On Sunday, January 26, 2020 at 7:14:12 PM UTC-5, jfitch wrote:
...an electric retrofit for the AS self launchers.
The engineering and installation should be relatively simple.

Um, not on this planet.

Perhaps you did not catch the "relatively"? Engine bay is already there, the doors are there, it is engineered and built for the weight, the extraction mechanism is already there, even the prop and boom. So yes, "relatively simple" compared to retrofitting say an ASW27, which is being done, and has none of those things.

I am not a stranger to complexity, or aircraft design.

"How hard could it be"
That depends.
Certainly if you already have an engine bay, and lift mechanism, you have a great start. No engineering the hole in the fuselage, etc.
If you have a proven drive system, much of the next part is more easily accomplished.
2 meaningful issues with converting the later Schleicher ships:
1) Where do the batteries go? Engine bay has some room but CG possibilities become limited. Wing installation would most certainly involve major stuff in any of the hard tank wings. Support and service access are non trivial.
This is the major task on the '34. The rest is mostly transplanting proven motor and drive into the '34 from the 32E.
2) Engine bay size matters because it limits available prop diameter and this is a real issue in getting performance out of the drive.

I have some practical experience with this as I am now starting test flying of an ASW-24E that has been converted to electric.

How hard could it be?

The largest barrier is a lack of proven motor/ controller systems to incorporate into a project.
FWIW
UH

So how hard was it, for a very skilled and practiced professional? Will you be publishing an article in Soaring, a pre-writeup on RAS? Sounds very interesting.

On Tuesday, January 28, 2020 at 6:59:56 AM UTC-8, wrote:
On Tuesday, January 28, 2020 at 1:48:48 AM UTC-5, jfitch wrote:
On Monday, January 27, 2020 at 7:04:36 PM UTC-8, Dave Nadler wrote:
On Sunday, January 26, 2020 at 7:14:12 PM UTC-5, jfitch wrote:
...an electric retrofit for the AS self launchers.
The engineering and installation should be relatively simple.

Um, not on this planet.

Perhaps you did not catch the "relatively"? Engine bay is already there, the doors are there, it is engineered and built for the weight, the extraction mechanism is already there, even the prop and boom. So yes, "relatively simple" compared to retrofitting say an ASW27, which is being done, and has none of those things.

I am not a stranger to complexity, or aircraft design.

"How hard could it be"
That depends.
Certainly if you already have an engine bay, and lift mechanism, you have a great start. No engineering the hole in the fuselage, etc.
If you have a proven drive system, much of the next part is more easily accomplished.
2 meaningful issues with converting the later Schleicher ships:
1) Where do the batteries go? Engine bay has some room but CG possibilities become limited. Wing installation would most certainly involve major stuff in any of the hard tank wings. Support and service access are non trivial.
This is the major task on the '34. The rest is mostly transplanting proven motor and drive into the '34 from the 32E.
2) Engine bay size matters because it limits available prop diameter and this is a real issue in getting performance out of the drive.

I have some practical experience with this as I am now starting test flying of an ASW-24E that has been converted to electric.

How hard could it be?

The largest barrier is a lack of proven motor/ controller systems to incorporate into a project.
FWIW
UH

The engine bay is quite large, and would be unoccupied by motor and muffler, and requires about 170 lbs to achieve normal W/B. The space in the wheel well used for the fuel tanks is also available, though the volume in the engine bay alone is probably enough. In my post I suggested that Schleicher do this (instead of the 34), they have already developed the motor/battery/controller for use in other gliders, so that is not a barrier for them. Thus "relatively simple". I'll stand by that characterization.

I wonder if you had a plane with ballast bags, if that would make wing batteries easier.

Not sure if the wing structure expects such concentrated loads?

An interesting question.Â* How does the mass of the batteries compare to
that of water?Â* In my old LS-6a the water was held in bags which ran
from the root almost to the tip ahead of the spar.Â* They were drawn in
by a light rope and pulley system.Â* I would imagine that the battery
cells could be arranged in line, like a machine gun belt and pulled into
the wing thus distributing the load.Â* A lot would depend on the weight,
I suppose.

On 1/28/2020 9:58 AM, wrote:
I wonder if you had a plane with ballast bags, if that would make wing batteries easier.

Not sure if the wing structure expects such concentrated loads?

--
Dan, 5J

El martes, 28 de enero de 2020, 15:02:36 (UTC-3), Dan Marotta escribió:
An interesting question.Â* How does the mass of the batteries compare to
that of water?Â* In my old LS-6a the water was held in bags which ran
from the root almost to the tip ahead of the spar.Â* They were drawn in
by a light rope and pulley system.Â* I would imagine that the battery
cells could be arranged in line, like a machine gun belt and pulled into
the wing thus distributing the load.Â* A lot would depend on the weight,
I suppose.

On 1/28/2020 9:58 AM, mail.com wrote:
I wonder if you had a plane with ballast bags, if that would make wing batteries easier.

Not sure if the wing structure expects such concentrated loads?

--
Dan, 5J

In my case the battery pack weight is 18kg and 1.5m long.

That mass in that distributed area is not that critical.

On Tuesday, January 28, 2020 at 9:59:56 AM UTC-5, wrote:
How hard could it be?

Here's an update from another skilled practitioner:
http://www.streifly.de/news-e.htm

Dave Nadler wrote on 1/31/2020 12:15 PM:
On Tuesday, January 28, 2020 at 9:59:56 AM UTC-5, wrote:
How hard could it be?

Here's an update from another skilled practitioner:
http://www.streifly.de/news-e.htm

Any idea what the "electromagnetic disturbances" are disturbing?

--
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 Friday, January 31, 2020 at 7:27:53 PM UTC-5, Eric Greenwell wrote:
Any idea what the "electromagnetic disturbances" are disturbing?

The Force.