The Gakken Cross Copter: Two rotors for twenty-seven dollars

Gakken Cross Copter

This is a Gakken Cross Copter, which can be yours, as it was mine, for 1886 yen plus delivery from HobbyLink Japan. (It's something like $US27 including the cheaper Surface Air Lift shipping, as I write this.)

The helicopter itself has two contra-rotating rotors, which are driven by one minuscule electric motor. The motor is tethered to a hand-powered generator, which you must crank with considerable enthusiasm to get the Copter airborne.

I was glumly contemplating a 600-take video session (with the cats, who find the Copter utterly fascinating, banished from the room...) to try to get some decent footage of the Copter in action. But fortunately, some people from Make Magazine got the chance to play with a prototype:

The prototype seems bulkier than the production Copter, and has a longer cable. But the principle's the same.

Because the power wire tugs on the bottom of the Copter, it tends to pull the bottom of the aircraft toward you, which causes it to fly away from you. This can rapidly get out of hand. Fortunately, you can just stop turning the handle and let the copter fall and dangle from the wires without damage. It seems to be pretty tough, too, considering its gossamer construction; the two interleaved rotors often end up mis-meshed after a crash, but if they haven't managed to get completely jammed, just twitching the generator handle back and forth a little will usually sort them out.

The generator's quite beautifully coupled to the tiny motor in the Copter. You only need a slight turn of the crank handle either way to get the rotors turning. It acts more like a drive shaft than an electrical linkage.

As with the immortal Vertibird (which actually did have a drive shaft from the power unit to the tethered helicopter), the Cross Copter's remote power source makes it lighter. The Copter by itself, not counting the tether wire, weighs only about 8.5 grams (that's 0.3 ounces). The whole 110cm (3.6 foot) length of the power wire adds only about one more gram.

The Copter's smaller than I expected, though. The diameter of each four-bladed rotor is a bit less than 12 centimetres (4.7 inches).

You also have to assemble the Cross Copter yourself, but this will only take a few minutes. As with so many Japanese hobby products, the packaging is beautiful - in this case a box with a short instructional magazine for a front panel. The instructions are all in Japanese, but the pictures are more than adequate to figure out how to click the few parts together. You need to squeeze rather hard to get the landing skids to click onto the bottom of the Copter frame, which could be beyond the hand strength of a small child, but the rest of the assembly should be no problem for any intelligent kid.

Getting the Copter to take off from a surface is dodgy at best, because of the wire-making-it-fly-away-from-you problem. If you've got someone to hold the chopper for you while you get it up to speed, though, you'll be fine.

(If you go for hand launching, you could also delete the two skids on the bottom, dropping a little more precious weight. It's not as if you're ever likely to use the skids for landing, after all. It's probably not completely physically impossible to get the Cross Copter to land, but I'm buggered if I know how you'd go about it.)

You can, these days, get a proper self-contained remote-controlled tiny helicopter for not much more than the price of the Cross Copter. The Interactive Toy Concepts Micro Mosquito, for instance, is a highly insectile (it has eyes!) twin-coaxial-rotor beastie that weighs only about fifteen grams and seems to cost only around fifty bucks. And it seems to be quite controllable...

...which is more than can be said for its predecessors, the foam-bodied Picoo Z and its endless clones - some decent, some awful, all very cheap.

For proper airlift-a-sugar-lump-to-your-tea control, you need something like the incredible Pixelitos or the Proxflyer prototypes that led to the mass-market Micro Mosquito, but you can at least try to control even the worst Picoo clones. The Cross Copter pretty much just goes where it feels like going.

(The Cross Copter actually has a similar stability system to the Prox/Picoflyer; its rotors are rigid, but loosely connected to the drive shafts, so they can flop around to counter movement of the Copter's body.)

If you want a helicopter, you don't want a Cross Copter. But if you want a neat little not-too-expensive toy that's half science project, half party novelty, the Cross Copter's the only game in town.

Not a lot of people seem to be buying the Cross Copter from HobbyLink Japan, because as I write this the "People who bought this item also like" section on HLJ's Cross Copter page contains nothing but items from my own last HLJ order!

I hope, faithful readers, that you'll at least manage to add that little Sherman to the end of the page.

2 Responses to “The Gakken Cross Copter: Two rotors for twenty-seven dollars”

  1. Changes Says:

    I'm not too impressed by anything that can't fly under its own power. To me, such toys have all the sense of a Flintstones car.

    About the Picoo Z clones, I'll say this: I own both a genuine Picoo Z and a DealExtreme knockoff (the first they added to their collection, the unremarkable "world's smallest helicopter", before they started adding other canopies and whatnot). The knockoff was much, much stabler and far more enjoyable to fly. I say "was" because a particularly nasty hit on the tail caused the tail motor to be separated into its component parts. I then foolishly decided to cannibalize the knockoff for parts to use in the genuine Picoo Z instead of doing the opposite, on the grounds of the real thing costing me three times as much. I shoulda have transplanted the PZ's tail motor on the knockoff instead. Oh well, live and learn.

    The Mosquito has two knockoffs on DealExtreme, but there are some cheaper helis that have the price of a Picoo Z knockoff while also having three channel control. I ordered one just the other day. I already own an "old" Mosquito knockoff, with the four-bladed wire-enclosed rotors (instead of the much more sensible ones with two pivoting blades per rotor, which DX put on sale a few days after I ordered mine, grr), and I'm curious to see which of the two flies better.

  2. Red October Says:

    I work at Radio Shack and we sell the Micro Mosquito; it is indeed very controlable once you get the hang of it. It may or may not need to be balanced out (It has trim and balance controls) and a propper RF transmitter instead of the rather lousy IR jobber some of our other flying toys have...

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