Tunneling a FPV Quad, the long way [Drone Drönare]
A pass through Söderledstunneln in Stockholm, Sweden.
Done at 1.30am on a weekday with spotter and actually not illegal as long as you dont stay above traffic. At least for a few months more so I wanted it done since it was a thing I wanted to shoot for over a year.
Easy thing, but still a very cool experience.
At these low speeds at around 70km/h you can easily hit something the size of a normal computer screen time after time after time after time with a drone like this so there is a LOT of space in there.
70km/h is slow for a powerful 1800kv 6s FPV drone capable of over 160km/h which it reaches from stand still in way below 5 seconds. 70km/h is a cruise at like 30% throttle which is imortant as you need throttle to break OR for fast and sudden accelration. There is about 7 horsepower per kg to do either, compared to less than 1 per kilogram in something like a Formula 1 car, so this thing can get out of Dodge in 2-3 shakes of a lambs tail or stay in it for that matter - faster than anything. 70-0km/h in less than 5 meters.
It's light, exact like crazy on a slow long straight like this - and powerful beyond belief.
How was it prepped and done?
To begin with this is at 1.30 am tuesday night for minimal traffic.
Range and control plus videolink was tested prior as well as the drone itself. And similar flights but outdoors had been flown with the same drone (or quad) multiple times. On top of that in a shorter but much more narrrow tunnel as well as in concrete structures of many designs to find out if for instance high output power might cause multipathing problems in a tunnel (which it doesn't at 800mW or below) and the tunnel itself was completely free on the channels choosen and used.
It was scouted and rescouted as well as me being fed information about everything ahead from connecting tunnels or from behind - in real time.
The drone is capable of stopping from 70Km/h in under 5meters and land or get dropped on the shoulder in less 3 seconds in a pinch to then just get collected.
It's total weight is 720g and radio connection both for controls and videolink was pretested and failsafe set to immediate drop. One antenna for videolink was on roof of the car and one on the goggles.
Radio link is by crossfire on 250mW monitored constantly during flight without ever dropping below 98% as well as the relative RSSI for the videolink which was on 800mW. These numbers normally give you worst case scenario (with line of sight as we had) 1km of range and under normal circumstances at least double. We stayed within 150m from the car at all times and only went outside of line of sight the last 30 meters before landing. The drone can easily be controlled 2 stories above or blow your location in something like a parking house for reference.
Antennas for Crossfire was two Immortal-T's and on the radio a Diamond. For video there was a 150mm long iFlight Albatross on the drone, the same one on the Fatshark Goggle reciever (RapidFire) as well as a TBS Triumph Stub mounted by magnet holder on the roof of the car (visible at 3.24 front right on the car)