Squishable Plane

Cynbe has been thinking about learning to fly r/c (radio control) model planes again. He started some years ago, but at that time he gave it up in favor of other more pressing things on his plate. While we’re in Santa Cruz, things are feeling stable enough that he wants to try again — plus, being outside in the Cruz is glorious any time of year (though lots of folks born in Austin said they feel that way, too).

The hardest part of learning to fly r/c is the beginning, when it’s only too easy to crash and destroy your model plane. Cynbe is the methodical one in our marriage, and after carefully researching online, he came up with a model called the Great Planes U-Can-Do EP. This trainer seems to have been around since 2003; the last mention of it on a discussion board is in 2005, but it’s still being manufactured and is in stock at the usual places. Superficially it resembles most trainer foamies — except that, unlike any other plane we’ve seen, it is waaay flexible, even floppy…actually, um, squishy. Literally: this plane is made of such soft foam that you can bend it double. Here’s Cynbe demonstrating by bending a wingtip. Yes, it pops right back when he lets go.

Cynbe bends a wingtip of the U-Can-Do EP
Cynbe bends a wingtip of the U-Can-Do EP

That line down the middle of the cockpit area is a zipper. That’s right, the fuselage is so flexible that it unzips like a purse, and inside are the battery, receiver, and motor control. The wing is not flat; it has a normal airfoil cross-section. It is actually built up just like a balsa wing would be, with longitudinal spars and formers and a skin, but they’re all made of super-flexible foam. You can also bend the fuselage double with no discernible ill effects. Here’s a better view of the squishy wing, from Johan Sundqvist’s page.

Johan Sundqvist's U-Can-Do EP, majorly bent but totally unharmed
Johan Sundqvist’s U-Can-Do EP, majorly bent but totally unharmed

I visited various forums, and found some folks who hated this plane. Their reasons varied from tirades about the control horns breaking at the slightest shock to the engine being hopelessly underpowered to the fuselage ripping apart during normal maneuvers. We’ve adopted Beginner’s Mind for this project; I want to know what’s wrong with the design and what we can do to make it better, because if it does what Great Planes claims it does, it should be a big help indeed for the rank amateurs among us who are willing to learn by doing. So far, we’ve assembled the airframe; in the next few days we’ll populate the electronics. Then we’ll see what this puppy can actually do.

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