CineLog25 WSML Sub250g


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Featuring: GEPRC CineLog 25 sub 250g

Including

  • Walksnail Moonlight 4K VTX with two antenna
  • Radiomaster RP3 ELRS RCV with two antenna
  • Battery Tattu 4S 850mAh 95C
  • Foam cover giving buoancy in case of failsafe over water

Idea

I wanted to build a sub 250g quad with 4K video recording for a sailing event. As I'm invested in the Walksnail Avatar from the beginning, I decided to use the new Moonlight VTX for this project. The quad should be a sturdy and lightweight cinewhoop that can fly over water without the risk to loose it in case of a failsafe. It should also weigh less than 250g to safely and legally fly it in the vicinity of people.

Choosing the right QuadCopter

There are several suitable quads in the market. I wanted to use the largest quad that can fit under 250g. I decided for the GEPRC CineLog25 because of some very positive youtube tests. The original CineLog25 equipped with the Moonlight and 850mAh battery weighted around 275g. But I like to tune things to their maximum and accepted the challenge.

Stripping CineLog25

  • GPS removed (takes too long to get a sat fix anyway)
  • Removed all screws and standoffs removed body
  • Bottom carbon plate removed
  • Motors moved outside by one hole and mounted with only two flange screws each (improves airflow and flight time)
  • FC, VTX and bottom plate now mounted by 2mm nylon straps
  • Battery and canopy now hold by thin rubber bands
  • Canopy and bottom plate carved from 10mm foam boards
  • Battery cables shortened to a minimum
  • All adhesive foils removed from battery and replaced by single capton tape

Flight time now is 7-8 minutes until 3.5V/cell.

Downloads

Last Flight and Falling out of the air

The quad had issues with falling out of the air from the beginning. Once, the right rear motor would not spin up anymore. Measuring its wires with a multimeter did not show any broken cables. So I replaced the rear two motor with similar HGLRC Aeolus 1404 4800kV motors.
In mid of august, I used the CineLog25 to film a sailing regatta. I flew 5 packs that day without any issues. Then I started with my last battery pack. After 3.5 minutes, I gave full throttle to reach a sailing boat 50m ahead against the wind. Next, I saw that the quad was falling out of the air into the water. The CineLog25 was gone. The foam boards did work in keeping it afloat. Immediate apnoe diving and even scuba diving at the next day did not help to find it up to now.
The reason why it fell out of the sky is still unknown. Maybe it was an issue in the flight controller.

Gregor Rebel in Summer of 2024









[jpg, 285kB]
#001: Total Quad including Walksnail Moonlight and 4S 850mAh Tattu 95C weighs less than 250g 		[jpg, 349kB]
#002: Replaced screws and standoffs by nylon zippers and carbon by foam sheets 		[jpg, 382kB]
#003: shortening battery cables and removing foils gave another 8gramms