Electric Self Launch System

El viernes, 8 de junio de 2018, 16:59:09 (UTC-3), 2G escribió:
On Friday, June 8, 2018 at 6:51:52 AM UTC-7, Emir Sherbi wrote:
El jueves, 7 de junio de 2018, 20:41:10 (UTC-3), 2G escribió:
On Monday, June 4, 2018 at 9:09:00 AM UTC-7, Emir Sherbi wrote:
Hi everyone,

My name is Emir Sherbi, i'm a mechanical engineer from Argentina. With a partner who is an electronic engineer we've designed an electric self launching system that can be retrofitted in most of the composite sailplanes. Some of you may be saw my booth in the SSA convention in Reno with the mockup of the prototype.
The idea is to sell it as a kit so you don't have to ship the glider to my country. The modifications to be made are very simple. Any repair shop have enough knowledge to do it.
These are the links for who are interested in following the project..

https://www.instagram.com/grasshoppersystem/
https://www.facebook.com/charlysierragolf/

Kindest Regards

When I stopped by your booth, you indicated that this system is still in development with much work left to be done. Is this accurate?

Tom

Hi Tom


The most difficult part that we are working on is the battery pack supplier and testing. In other hand we also are starting to build our own motors, not only for this application but also for another types of vehicles (mostly agricultural). But for the US clients we can supply any already known motor brand to power the kit.
As you can see on the pages that i shared, we are starting to work on the fuselage. The pylon is on its final revision for flight testing but we are still working on the batteries.

Regards

Which battery chemistry are you going to use?

Tom



INR and IMR, depending on the flight mission.

Regards

On Friday, June 8, 2018 at 4:50:33 PM UTC-4, Emir Sherbi wrote:

INR and IMR, depending on the flight mission.


https://breazy.com/products/samsung-...50-25r-2500mah

INR 18650 2500mah Battery (2 Pack) - Samsung

20 amps of continous discharge, the Samsung 25r has been the go to battery for most vapers because of its authenticity and its transparent rating system. In terms of cell degradation the Samsung 25r has been a reliable source of power.

On Friday, June 8, 2018 at 6:30:29 PM UTC-5, son_of_flubber wrote:
On Friday, June 8, 2018 at 4:50:33 PM UTC-4, Emir Sherbi wrote:

INR and IMR, depending on the flight mission.


https://breazy.com/products/samsung-...50-25r-2500mah

INR 18650 2500mah Battery (2 Pack) - Samsung

20 amps of continous discharge, the Samsung 25r has been the go to battery for most vapers because of its authenticity and its transparent rating system. In terms of cell degradation the Samsung 25r has been a reliable source of power.

Flub, are you implying this project is vapor ware?

On Friday, June 8, 2018 at 8:28:04 PM UTC-4, wrote:

Flub, are you implying this project is vapor ware?

Not at all. I think it is brilliant that millions of vapers have volunteered to do rapid discharge testing of INR battery technology. And a mass market battery like this should benefit from manufacturing economies of scale and competition.

Interesting additional battery chemistry info.....

https://batterybro.com/blogs/18650-w...ally-explained

On Friday, June 8, 2018 at 6:30:32 PM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
Interesting additional battery chemistry info.....

https://batterybro.com/blogs/18650-w...ally-explained

And here is a lot more detailed info:

http://batteryuniversity.com/learn/a...of_lithium_ion

While the safety of IMR and INR are good, they are not as good as LFP.

Tom

Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.

On Saturday, June 9, 2018 at 11:54:06 PM UTC-4, Emir Sherbi wrote:
Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.

I'd be very happy to have something soon that could sustain 30 minutes of flight at best glide speed. Maybe I'd upgrade to self-launch later when higher energy density batteries become available, but maybe not.

The 'best' is the enemy of the 'good enough'.

Having learned my lesson with Betamax, I'm looking for the VHS of electric propulsion. My glider is 20 years old. There is a limit to how much I want to sink into it.

"I'm looking for the VHS of electric propulsion."
And we wonder why we're decades behind the Europeans...

El domingo, 10 de junio de 2018, 21:30:15 (UTC-3), son_of_flubber escribió:
On Saturday, June 9, 2018 at 11:54:06 PM UTC-4, Emir Sherbi wrote:
Yes, they are very reliable and stable. They have very long life cycle. But the energy density is lower. For the same capacity you have to think in more than 60% of weight increase.

I'd be very happy to have something soon that could sustain 30 minutes of flight at best glide speed. Maybe I'd upgrade to self-launch later when higher energy density batteries become available, but maybe not.

The 'best' is the enemy of the 'good enough'.

Having learned my lesson with Betamax, I'm looking for the VHS of electric propulsion. My glider is 20 years old. There is a limit to how much I want to sink into it.

For our design, having only 30 minutes of sustained flight or selflaunch and having 1 hour of sustained flight is the same technological challenge.
The only thing that changes is the final price.

20 years old is like new, we are about to install it on a 35 years old Pegasus.