Fourdan's blog View Details
Posted by Fourdan | Aug 05, 2020 @ 07:44 AM | 5,795 Views
I started Scorpion Calc kernel in 2002
Now, in 2020, it is time to present some "insides" like a bonus.
First chapter about the permanent magnets brushless motors (PM-BLDC)
In 1997, I started to participate to "miniature RC solar cars" challenges with small DC brushed motors (Portescap + integrated gear-box)
In 1998, I started a first calculator (under Visual Basic) to find the optimum gear-box ratio, taking into account the resistive torque.
I won (easily) the challenges up to 1999, when suddenly, in 2000 a competitor beated me in max velocity !
I asked him to show me the "under body": he was using a small brushless Astroflight motor (+ gear box) but had some difficulty to start from stop!
After some readings, I decided to try also that solution (BLDC) in direct drive.
Rapidly I found that a low Kv was mandatory and began to wind some small BLDC coming from PC CD-ROM
I was learning about neodyme magnets to replace the ferrite original poles
and about the number of turns acting on the Kv (rpm/V)
I was in contact with Ales Pelikan concerning the AXi outrunners (specially AXi 2808- kits)
I developped a calculator but Ales was not convinced with the commercial interest
After several trips in China I met or/and visited Scorpion, Dualsky, DBY (motrolfly, A2Pro), XYH and two engineers by G&S models.
I developped Aeronuts Calc for some years
In 2007, I started a friendly relation with Georges VG in Hong-Kong (my son's family was living there)
I started Scorpion Calc based on my testings (no-load and with props via my bench, inspired by Dr Kiwi L shape static stand)
around 2008 I started Dualsky Calc and Motrolfly Calc on the same kernel
---
Now we are in 2021, I am 82 y and my legs are tired. I have a very bad mobility. No possibility to go to the RC field.
Louis
Posted by Fourdan | Aug 02, 2015 @ 12:13 PM | 16,274 Views
Solar RC cars at Technolac in Bourget-Le-Lac (France)
Same solar car as in 2014 except some minor modifications
Now the solar panel is dismounted easily with 5 screws
The residual car body can run alone with the(a) battery

This year we ran on 100% solar (no propulsion battery)
but to avoid to stay stopped under a tree shade, I installed a Scorpion guard (Rx 5V under a small lithium battery)

The first day (saturday), rapidly we were the race leader , but we observed from time to time an erratic radio-link 2.4GHz failure for 1 - 2 seconds. One radio-down period was very hard as the car collided a tree at around 30 km/h.
The solar module was strongly destroyed at the front.
Then our speed was reduced by two (only 15 km/h) and we went down in ranking at the end of 2 hours.
Saturday night I repaired the solar module, changing 4 solar cells.

Sunday morning again 2 hours of racing.
Full speed again, we were going up in the ranking, unfortunately after around one hour, our car was destroyed when an adverse assistant walked on our car during a traffic jam-stop between 3 cars. He said "sorry I didn't see you, my apolodgies""
We were obliged to abandon.
Finally we are finishing at rank 9 on 22 qualified cars (on 37 registered)
Pilot was Olivier (excellent amateur driver)
Louis
Pictures : first day before and after the "tree collision"
Posted by Fourdan | Jun 22, 2014 @ 05:16 PM | 17,906 Views
Solar RC cars at Technolac in Bourget-Le-Lac (France)
I have participated at the 2014 race (2 times 2 hours races on 2 days)
Good first race (2 hours, saturday 7th june)
Unfortunately on sunday our solar panel got in failure following a collision in the traffic. We abandonned because repair was too difficult under the PV panel.
Attached some pictures
Olivier was the first pilot, Laurent the second
Louis
Posted by Fourdan | Oct 03, 2009 @ 04:09 PM | 18,768 Views
1) Solar-RC-cars specialist, since 1997

2) Developping some BLDC freeware (Scorpion Calc, Dualsky Calc, Motrolfly Calc, .... MM-Calc, Himax Calc, AeroNuts Calc ....)

3) EcoMarathonShell, EducEco challenges in all-electric or solar categories

4) Anything about brushless motors upto 20 kW

5) Anything about BLDC controlers (ESC, sensored and/or sensorless)