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?

On 1/24/20 8:07 PM, wrote:


I do hope they find safer battery chemistries before long. LiFePO4 is much safer, but the energy density is even poorer and the cost even higher.



Reading more on the Alice project, they intend to do an Extended Range
version with about 750 mile range, pressurized cabin, and dramatically
upgraded batteries.

Aluminum-air batteries, with much more energy density than
lithium-cobalt. Aluminum anodes are reduced to hydrated aluminum.
Unfortunately they're primary batteries, not rechargeable. To reuse,
you just extract the anodes, and refine them back to aluminum. Easy in
theory, but may slow down a commercial operation. Or you keep spare
batteries on hand, and swap them out. Probably not with a fork truck,
didn't see any cargo doors on the Alice.

This will be certified and in commercial operation by 2023, buy your
tickets now.

-Dave

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 1/25/20 2:54 AM, Martin Gregorie wrote:
On Fri, 24 Jan 2020 20:27:45 -0700, kinsell wrote:

On 1/24/20 8:07 PM, wrote:
On Friday, January 24, 2020 at 12:21:41 PM UTC-5, kinsell wrote:
On 1/24/20 9:58 AM, Steve Leonard wrote:
Good to run those tests at night so you can see the fire sooner.


Good point. But if the main battery ever lit up (8200 lbs of
lithium-cobalt) it ought to make quite a bonfire.

Somehow flying that thing makes me think of the guy riding the H-bomb
in Doctor Strangelove.

I do hope they find safer battery chemistries before long. LiFePO4 is
much safer, but the energy density is even poorer and the cost even
higher.


Good analogy. That was Slim Pickens, wasn't it?

Someone at Eviation said the thing is (or was) basically a battery with
a picture of an airplane painted on it. I wouldn't have guessed they
could get 8200 lbs of lithium battery in there and still have room for
px. It's am ambitious project, 600 mile range, but at some point
reality starts to rear its ugly head.

With a big motor on each wingtip (in the photos they look bigger than the
rear motor) I do wonder about its handling if one of the wingtip engines
fails/gets hit by a goose, etc., or do they just shut down the other
wingtip motor and land wherever possible.



https://www.youtube.com/watch?v=LsJ0vYnrMxo

A little more detail at about 18:20. They claim a climb rate at sea
level of 1200 fpm on just the rear engine. All three engines are the same.

Interesting comments at 11:15, using differential thrust in combination
with tail surfaces to handle cross winds. They say they'll demonstrate
35 mph crosswind landings.

On 1/25/20 9:07 PM, Emir Sherbi wrote:
When you have so much battery capacity. You have a lot power to spare (discharging or charging). If they use the full capacity in two hours without counting the reserve the rate of discharge is 0,5C. And the chare rate is 1C. That is not much workload for most of the popular cells. But you need a extremely big super charger.


What may work for one cell doesn't necessarily work for massive
series-parallel arrays of cell. If the cells don't stay well balanced,
interesting things can happen when you start pumping a million watts
into them.