One thing Great Planes isn't shy about is trying a revolutionary approach to solving a common problem. In this case, the issue is practicing those low-and-slow 3D maneuvers without fear of doing major damage to the airplane when the "dumb thumbs" come a-calling. Face it, the plethora of flat-plate foamies out there on the market are inexpensive and relatively tough, but they're nowhere near indestructable. Pile one in, and you're likely to end up spending a signifigant amount of time with the foam-safe CA and kicker, if the plane can be repaired at all.

Great Planes's new FlightFlextm technology takes rather unique approach to the issue. While the materials, EPP foam and carbon fiber, are hardly new to the foamie R/C industry, the way they're put together to make the UCanDo3D EP is quite novel. Conventional EPP foam construction consists of solid chunks of EPP shaped with hot-wire cutting equipment, and reinforced with carbon fiber rods, resulting in an extremely bounceable, but unfortunately heavy, airplane. Great Planes took the Zen approach of "bend, not break," designed an EPP framework similar to that of a built-up balsa plane, and sheeted it with a thin layer of EPP foam. The end result is an airframe that is surprisingly light considering what it's made of, amazingly flexible, and.... SQUISHY!

Wingspan: 33.5 in
Wing Area: 369 sq in
Weight (Recommended): 14-15 oz
Weight (As Tested): 13.7 oz
Wing Loading: 5 oz/sq ft
Length: 36.5 in
Radio: 4-channel with 4 micro servos and 30A brushed ESC
Power: 280BB motor, 5:1 gearbox

Equipment

Power: 280BB motor, 5:1 gearbox (included)
Prop: 12x8 GWS (included)
ESC: Castle Creations Griffin 35
Battery: Great Planes 1200mAh 3S LiPoly
Servos: Futaba 3108 sub micro
Receiver: GWS Pico 4-channel
Transmitter: Futaba 8UAPS

The FlightFlextm technology got its first real test on the trip from RCU headquarters to my place in Rochester, NY. When I got the box, it literally looked like it had gotten into a fight with someone, and lost. Even the inside box was badly damaged during transit, but as I pulled each part out and inspected it, there was no visible damage. Everything was intact! Still, I was skeptical as to how a couple of "funoodles" glued together would result in a flyable airplane.

Included in the hardware package are genuine pinned hinges, carbon fiber pushrods, special-purpose control horns, along with matching servo arms for three different types of servos. Great Planes includes special pushrod ends that are secured to the carbon fiber rods by way of a drop of thin CA. These fit in the special oversize holes in both the control horns and servo arms, and typical servo arms don't have enough "meat" in them to drill out to the right size. To use the stock pushrods, the buyer has to use a servo that one of the sets of arms fit. In my case, I used the recommended Futaba 3108 Sub Micro servos. With a street price of about $15, legendary Futaba quality, and better torque than the Hitec HS55, these servos are an awesome bargain.

Considering the low parts count, assembling the UCanDo3D EP is practically a slam-dunk affair. The main difference in the assembly is the recommended adhesive used to hold the plane together. Nope, it's not CA and kicker. It's not 5 minute epoxy, either. What's this magical mystery adhesive? It's HOT GLUE, low temperature hot glue to be exact, but hot glue nonetheless. To all those experienced modelers out there who have raided their wife's/mother's/girlfriend's craft or sewing supplies in the past, it's time for another mission to borrow the hot glue gun. Or, just break down and spend the $5 at WalMart for your own. Make sure it's the LOW TEMP hot glue gun and glue. High temperature glue will melt the EPP foam. There's nothing saying you couldn't use CA and kicker, or even epoxy, but frankly, hot glue works just fine and is the quickest way from the workbench to the air.

Attaching the small horizontal stabilizer is typical ARF fare: Center side-to-side, square up to the fuselage, and glue. The main thing to keep in mind is keeping the fuselage straight. Because this is a bend-not-break design, the fuselage is by no means rigid... The term "wiggle worm" comes to mind. Sight down the fuselage to ensure it's straight, then carefully measure from each tip of the stab to the nose of the airplane. Run beads of hot glue along the top and bottom of each side, then use the hot tip of the glue gun to smooth and "bake" the glue into the foam as described in the instructions for best results.

The assembly procedure wastes no time here. Next to be installed is the wing, which is again the typical ARF process: Insert, center side-to-side, square up to the fuselage, and glue. On this particular example, getting the wing slid into place seemed to be a little hairy; I was afraid of damaging the wing by pushing or pulling too hard on it. Patience won the day, though, and the wing finally slid into place. What was surprising is how much more rigid the plane became once the beads of hot glue were added to the wing/fuselage joint. Between the stabilizer and wing, the entire plane became surprisingly rigid, though there was still some signifigant waggle in the tail.

 

Once the wing is fixed in place, it's time to move on to the control surfaces, specifically the ailerons. To be absolutely truthful, this was the one frustrating part of assembling this plane. The instructions describe a hinging method where the hinges are glued in with hot glue. Unfortunately, the working time with low-temp hot glue is very short, and the glue is very hot. It's a neat trick getting a hinge with a half-cooled gob of hot glue into a slot before the glue completely cools. It took three or four failed attempts to get the technique down, and all I can say is that I'm glad that I only had to hinge the ailerons in this manner. Hot glue is nice in this respect because it can be reheated and removed from the hinges for the next attempt

The elevator is an interesting design intended to allow the extreme elevator throws necessary for 3D. Three short pieces of plastic tubing are attached along the trailing edge of the horizontal stabilizer. A carbon fiber tube threads through the plastic tubes, completing the hinge. Each elevator half is then hot glued to tube. The carbon tube rotates inside the plastic tubes for a near 180 degree range of motion. As with most of the assembly techniques, this was a new one on me, but it proved to be simple and effective.

Radio Installation

Great Planes designed the UCD3DEP with drawstrings running from each of the servo pockets to the radio compartment to make servo installation more convenient. Four Futaba 3108 servos, three short tugging sessions, and 8 dabs of hot glue later, I had the UCanDo's muscles in place. Even though the instructions recommend 12" extensions for the elevator and rudder servos, they're a little short to work with inside the radio compartment, so I ended up pulling the servos out and reinstalling them with 15" extensions.

Control horn installation could not be simpler. The locations are clearly dimensioned in the instructions, and all that's required is to cut a 3/4" slot in the prescribed location, and to snap the control horn in place.

It's at this point that I swapped out the stock Futaba 3108 servo arms for the ones included with the UCD3DEP. No surprise, they fit perfectly. Hitec and GWS fans take note here: None of the included servo arms fit the HS55, the GWS Pico or the GWS Naro servos. Each control horn and servo arm receives a "plastic Z-bend clevis" as Great Planes terms them. These are the little doodads that the carbon fiber pushrods slide into. Finally, servos are centered, surfaces are neutralized, and pushrods are installed. The pushrods are a bit of a tight fit in the plastic Z-bend clevises, but this is actually a good thing because it makes final adjustments easier, and helps the drops of thin CA hold them securely.

Power System

Great Planes includes a GD280 brushed motor and gearbox with the UCanDo3D EP, and they recommend a 3S, or 11.1V Lithium Polymer battery pack for power. I followed their recommendations and used the stock setup. Those of you familiar with my postings on RCU will probably say, "Hey! He always says brushed motors on 3S LiPolys don't last long." Well, this is a little different. Cheap can motors like the Speed 300 have brass bushings and flimsy wiper brushes that can't hold up to the high RPM generated by a 3S LiPoly. The motor that comes with the UCD3DEP is a 280BB, with ball bearings and replaceable brushes, so it should hold up fairly well. It's hardly ideal, but I wanted to see how it performed before condemning it. A Castle Creations Griffin 35 ESC and a Great Planes 1250mAh 3S LiPoly pack round out the power system.

All that's left is to button everything up, install the cowl and prop, and go flying! The included O-ring for the prop saver was a little too stiff to stretch over the prop, so I used a thinner O-ring from my assortment.

 

It was probably a little too breezy the day of the UCanDo3D's maiden flight, but I was anxious to see how the brushed setup would perform. Any doubts about the UCD3DEP's ability to handle wind were quickly washed away the moment I released the plane into the air. Even at less than half throttle, the sleek fuselage of the UCD3DEP cut through the wind quite well, though downwind passes were a bit on the lightning-quick side.

After a few circuits around the field and some slow aerobatics, I flipped the high rates on, and haven't looked back since. The 8 MPH wind was a little high to even attempt hovering, but everything else was fair game. Axial rolls were crisp and quick, and would be even quicker if I ran the ATV on my transmitter to 140%. The plane shows absolutely no signs of snapping with elevator input, even though maximum deflection is over 45 degrees, and will loop in about twice its length.

The UCanDo3D EP's real test came two days later when the winds had calmed down somewhat. I'm not a 3D pilot by any stretch of the imagination, but I was able to hover the plane longer than I have been able to hover any other plane. With the stock power system, the UCD3DEP can hover at half throttle, but doesn't really have much in reserve to pull out. It seems that most of the energy put into the motor above half throttle is simply cast off as heat, and what heat it is. After landing, the battery pack was hot enough to make it uncomfortable to hold for long, so it was definitely too hot. If you're going to run the stock power system, heed my advice: Keep your flights relatively short, and strictly limit use of throttle over half.

With that advice in mind, I continued to push the envelope of both the UCD3DEP and my own flying skills. During one flight, I said "Aw heck!" rolled the plane over on its back, headed for the deck, and began making low inverted circuits around the field. I've been looking to expand my repertoire, and the UCanDo3D EP's advertised toughness gave me the confidence to try some new maneuvers. It wasn't too long before the plane's alleged resiliency was put to the test. I got a little too low, caught the rudder, and plopped the plane in the middle of the runway. Okay, it wasn't the most violent crash, but the plane wasn't even scuffed.

Watch the UCanDo3D Ep in Action
5.00 MB

I've had many plane-ground contacts since the first flight, and the UCD3D has sustained very little damage, at least nothing that couldn't be fixed with a quick dab of hot glue. Most of these were minor tears in the EPP skin. I've dropped it, I've crashed it, I've stepped on it, and it just keeps coming back for more. The only thing I've noticed is that great care must be taken in how it's transported and stored. Remember your mother telling you not to make a face, because it would stick that way? Well, unless you store the UCD3DEP flat and straight, it will set up in whatever position it was left in. This doesn't adversely affect the plane's flying qualities, but it does look goofy. Luckily, the plane can be straightened out by leaving it sitting straight for an equal period of time. I recommend storing the plane hung up by the prop, or on a flat shelf.

Power with the stock power system and recommended battery are more than adequate for basic 3D maneuvers and general low-level hot-dogging. However, great care must be taken to limit flight times and full throttle usage to prevent heat buildup and possible damage to the ESC and especially the battery.

It's not indestructable by any stretch of the imagination; the instructions warn that a straight nose-in crash will rip the nose off, but even with that weakness, the UCD3D is far more resilient than your typical foamie. If you're looking for a plane to develop or hone your 3D skills in low and slow without fear, take a look at FlightFlex(tm) technology.