The story of building Reaper, my 500 mph RC airplane (part 2) By late April the plane was built: > carbon skins laid up from CNC-cut molds > waterjet-cut internal rib structure > 250N turbojet characterized with custom inlet and nozzle > 30ft catapult tested with a 3d printed dummy (it fell over so changes were made before the maiden) One problem left: nowhere to fly it. You can't test a 500mph jet at Piedmont Park. So I spent an entire afternoon cold calling farmers until one said yes, 3 hours south of Atlanta. His only condition: his wife and kids got to come watch. Test day 1: we drove down, set up, and then the rain and fog rolled in. The FPV camera kept fogging over. I made the tough call to pack the plane up untouched and drive 3 hours home. Test day 2 was the sunday before final exams, the last possible window of the semester. We spent an hour setting up the launch rail, and right as we were about to fly I reached for my controller. It was sitting at home. 3 hours away. My roommate Luca grabbed it and met me halfway. We got one flight in, right before sunset. Reaper hit 600 km/h (370 mph) on its maiden. If we hadn't flown that day, the plane would've sat in my apartment all summer. Sometimes the hardest part of engineering isn't the engineering. More soon.

Day 55: building a fault-tolerant RL octocopter as my first hardware project PROJECT COMPLETE! 🥳🙌 The drone survived single, dual, triple, AND QUAD failures in real-life test flights (everything above dual was out-of-domain for the policy). The final policy is a ~45k-param MLP (two 128-wide layers), running at 50 Hz onboard the flight controller with no companion computer. The policy was trained with MuJoCo + PPO via @puffer_ai, then deployed zero-shot: baked straight into ArduPilot's C++ at the AP_Motors level. Thank you to everyone who followed along!! 📸: The policy surviving an initial single failure (back motor), then a stacked dual failure (happens during zoom in), for a total of 3 dead motors.

Somehow someone gained access to my account for a moment earlier today. Seems like they created some crypto token and used my platform to advertise it. Luckily their posts didn't gain much traction. I never have and never will create/endorse any token relating to my work.

My OG post now has a completely false community note that claims I did not design this plane, so I would like to clear some things up. This plane is my design. The body shape is similar (not identical) because that’s what’s optimal for these design constraints. Rockets are all tall and pointy. I’m sure Niels is an incredible engineer, and his plane is amazing. But this is my plane, designed by me from scratch (you can see a full 5-month building in public series on my LinkedIn, posted in realtime) and I’ve been building RC planes continuously since I was 10 ( Took a closer look at Niels' video now, and here’s just a couple of the most obvious engineering differences I can reveal: > Niels’ plane design is literally not available online. There were no build plans to copy from, but from photos it looks like he used foam+fiberglass overwrap. My plane is fully custom carbon fiber (internal structure CNC cut + skin, which I designed molds for and laid up myself). > My fusion file has 1480 operations. I pulled dozens of all nighters (in my dorm!) to make it fully myself, from scratch. > Fully custom inlet design with a bled boundary layer (not pictured in the OG post CAD, I iterated on it later. Pictured here) > Fully custom DMLS 3D printed titanium nozzle (looks like Niels uses a stock nozzle? either way looks nothing like mine, feel free to look at photos of my nozzle + dev process on my LinkedIn) > FPV (mine) vs line of sight (Niels) > Launch method: I use a completely different custom 30ft aluminum extrusion catapult There’s several more innovations that I can’t reveal right now to protect IP. The design is mine, and I’ve had no problem proving that to any VC who has asked. You don’t have to take my word for it: more to come, stay tuned.

Since February, I've designed and built the world's fastest RC airplane in my college dorm, and that’s not clickbait. Reaper has a 5kg carbon-fiber frame, 250N turbojet, and flies at 500mph. New to X and will be going through the whole build here in the coming days. #aerospace#