During the testing phases of the FI-AUAV project, I spent tons of time building and destroying RC planes. To save myself tons of time and money, all of these planes were built from foam and cut out with my FI-FoamBurner. Since 90% of the crashes (some even from extremely high altitudes) only resulted in airframe damage and no electronic damage, I could literally have a new plane ready to fly the next day (at around $12 all in for the foam, tape and glue).
Normally I would use Depron foam for the constrcution of the main body, wings and tail. Depron is a closed cell polystyrene product, manufacured into sheets of a standard size. It is extremely lightweight and moisture resistant. Developed as a high performance for floor insulation, now Depron has a wide variety of uses such as food packaging, but more recently in Modeling due to it’s light weight and rigidity. Because at longer lengths depron isn’t very strong – I would usually head over to the kitchen and grab a couple wooden BBQ skewers to re-enforce the wings and tail.
Foam Test Airframes Everywhere..
Normally for flight hardware and code tests I would build airframes that were as light as possible to allow me to get out of sticky situations extremely fast. I normally use something like a 2200Kv motor averaging about 24oz of thrust on a plane that was around 20oz so the thrust to weight ratio was in the “very maneuverable” butter zone similar to a Extra EA-300. Below is a video demonstrating a airframe I made with huge moving air surfaces when trying to program the plane to vertically hover.
Crashes & Repairs
Post Crash..
It was inevitable that these planes were going to crash since I was using them to test code as well as specific pieces of hardware for the first time. The reason I initially created them with a crazy thrust to weight ratio was to allow for weight additions during repairs. Since Depron is a very dense foam, it breaks rather then explodes on impact. This fantastic characteristic of Depron allow for repairs to be done extremely fast with some hot glue and packing tape.
System Tested
- GPS Systems
- Air speed indication system
- Inertial measurement unit
- Ultrasonic sensors
- Flight recovery systems
- Autonomous take-off and landing