People in the model airplane world have been building precisely these kinds of planes for probably at least two decades. In that sense, nothing new. That said, good to see the idea reaching a different audience.<p>If you want to save some weight you can buy small diameter carbon fiber rods for the pushrods (rather than using steel). You can also stiffen the wing by using a carbon fiber spar (either epoxy or cyanoacrylate to the bottom surface. If you know what you are doing you can even lighten it by cutting holes in the wings (think: punching out a bunch of circles) and then use packing tape to cover top and bottom surfaces.<p>That said, a light plane isn't always better. Some of my best-flying RC planes are not what anyone would characterize as light. For example, an electric-powered glider that weighs eight pounds (3.6 kg), can go straight up like a rocket, glide (power off) at over 120 mph and thermal with the birds with great agility and control. The problem with very light RC planes is that they can be very difficult to fly in windy conditions, this is particularly true of inexperienced pilots.<p>Here are some examples (no affiliation):<p><a href="https://www.wmparkflyers.com/EPP-Foam-Airplanes" rel="nofollow">https://www.wmparkflyers.com/EPP-Foam-Airplanes</a>