// FLYSIGHT 2 GUIDE · ENGO 3 · ACTIVELOOK HUD
Use an ENGO 3 HUD with FlySight 2
HONEST HARDWARE STATUS · UPDATED 9 SEPTEMBER 2026
The Groundrush firmware sends live FlySight 2 flight data to ENGO 3 glasses through the ActiveLook display system. Groundrush on the phone installs the firmware, binds a specific pair of glasses and provides the HUD controls.
The link, the layout editor and the individual HUD settings are all built and shipping in the beta, with the phone drawing each change straight into the display while you work. A layout arranged from the phone has been flown and read in the air. The individual controls that still have no hardware run behind them are named below instead of hidden.
What you need
- A FlySight 2.
- ENGO 3 glasses running ActiveLook firmware.
- The custom ENGO HUD firmware for the FlySight 2.
- Groundrush on iPhone or Android for binding and configuration.
1. Install the FlySight firmware
On a computer with Chrome or Edge, open the FlySight 2 firmware flasher. It reads the public-key line from flysight.txt, selects the encrypted image for that manufacturing batch and verifies its SHA-256 checksum.
Put the FlySight into its orange-light bootloader, select the FlySight drive and let the flasher place APP.SFB under FW/. Eject the drive before powering the logger back up. The complete manual path is on the flasher page too.
2. Bind the ENGO 3 glasses
- Unplug the FlySight from USB and connect to it from Groundrush's Device tab.
- Open the ENGO 3 controls and scan for the glasses.
- Select the intended pair. Groundrush writes that binding to the FlySight so the logger reconnects to the same glasses.
- Confirm the HUD status shows a live glasses connection before relying on it outside.
3. Choose what the HUD shows
The current beta can arrange altitude, horizontal and vertical speed, glide ratio, satellite status, logger and glasses battery, firmware version and takeoff indication. Each reading can be moved, resized, hidden or given its own units and decimal precision.
The phone draws the layout in the glasses while you work, so you are arranging it against the real display rather than a mock-up. Layouts built this way have been flown, but yours is yours: read it on the ground first, and treat it as a test layout until you have seen it in the conditions where it will be used.
What has been run on hardware
- The app downloads the right published firmware and updates a FlySight over Bluetooth. This was done from a phone; which platform that phone was is not recorded, so it is not a claim about Android or about iPhone specifically.
- ENGO 3 glasses connecting to the FlySight and staying connected through a jump.
- A HUD layout arranged from the phone, written to the logger and read in the air.
- The navigation reading: direction and distance to a stored landing zone, checked through the glasses and read in flight.
- The web flasher selecting and installing the batch-specific image over USB, on a real FlySight 2.
- The image shift and the individual HUD settings — refresh rate, HUD on or off, airspeed — written from the phone and followed by the glasses.
Built, with no hardware run recorded
- Any refresh rate quicker than 333 ms between frames. 333 ms is the quickest ever flown here, and the shipped default of 250 ms has not been in the air.
Recovery and official firmware
A failed application-image copy does not overwrite the FlySight bootloader. Return to the orange-light bootloader and copy a valid image again. To leave the custom firmware, obtain the appropriate release from the official FlySight firmware page and install it through the same bootloader mechanism.
Groundrush is an independent project and is not made by, endorsed by or affiliated with FlySight, ENGO or ActiveLook.