GREAT PLANES U-CAN-DO 3D 60 ARF
by Bob Motazedi
Aircraft Type: Fun Fly/Aerobatic
Mfg. By: Great Planes Model Mfg. Co., 1610 Interstate Dr., Champaign, Illinois 61822, (217) 398-8970, firstname.lastname@example.org
Expected Street Price: $189.99
Available From: Both Mfg. & Retail
Wingspan: 65 Inches
Wing Chord: 16.5 Inches
Total Wing Area: 1072 Sq. In.
Fuselage Length: 69.5 Inches
Stabilizer Span: 22-3/4 Inches
Total Stab Area: 182 Sq. In.
Mfg. Rec. Engine: .61-.91 2-stroke; .70-.91 4-stroke
Rec. Fuel Tank Size: 14.2 Oz. (Included)
Rec. No. of Channels: 4-6
Rec. Control Functions: Rud., Elev., Throt., Ail.
Basic Materials Used In Construction:
Fuselage: Balsa, Hardwood, Lite Ply, Fiberglass
Wing: Balsa, Hardwood, Lite Ply
Tail Surfaces: Balsa, Hardwood, Lite Ply
Building Instructions on Plan Sheets: NA
Instruction Manual: Yes (27 pages)
Const. Photos/Illus.: Yes
Radio Used: JR 10X Aileron PCM, 6 Servos
Engine Used: YS 120 AC
Fuel Tank Used: 14.2 oz. (Included)
Weight, Ready to Fly: 120 Oz. (7 Lbs. 8 Oz.)
Wing Loading: 16.1 Oz./Sq. Ft.
WE LIKED THE: Ease of assembly, light wing loading, 3D capability.
WE DIDN'T LIKE THE: Potentially weak main gear attachment, trim design on cowl not painted correctly.
Low inverted flight - the large thick wing makes inverted flight comfortable and easy. Nothing looks as cool as a ship this big flying.
3D aerobatics are now the rage at many flying fields. These fantastic maneuvers include slow, high alpha flight, water-falls, blenders, hovering and many other out-standing tricks. I recently started flying IMAC competition and wanted to learn 3D maneuvers without risking $3,000 worth of an airplane.
A month ago, one of my friends completed one of these larger U-Can-Do 3D kits and asked me to flight trim it for him. During the first flight, I was able to perform knife-edged circles, harrier approaches, a couple of short hovers and even a knife-edged loop! I was instantly hooked and ordered this kit!
Kit contents - everything comes packaged as seen here. Each part is neatly fabricated and covered leaving very little for you to assemble.
My kit arrived undamaged in a very large and sturdy container. The box is 66" long, 14" wide and 7" high. After opening the box, I was immediately impressed by the quality of the prebuilt parts. Every piece was safely packed in clear plastic bags. Compartments were all separated by sturdy cardboard pieces. Finally, the box itself was lined with long, wide strips of veneer sheeting. There were also pieces of this same type of wood which are bonded to pieces of foam for added protection.
A detailed 27-page manual is included in a separate package along with the decals and a warning sheet. This warning sheet basically tells the consumer to avoid using an engine with more than .91 displacement or a prop with more than 6" of pitch. This message concludes that if you ignore these warnings, flutter can occur with the extra large flying surfaces which can quickly result in failure and a certain crash.
The kit includes a bag of hardware which has all of the necessary nuts and bolts. Another bag has several precision laser-cut wood parts. A sturdy 2-piece nylon engine mount is also included along with all necessary pushrods and fittings.
The clear plastic canopy is protected in its own plastic bag. Only a little trimming with a pair of Lexan scissors is needed. A red spinner and a 14.2 oz. fuel tank with fittings are also included.
The cowl and wheel pants are made of molded fiberglass and are beautifully finished and painted to match the MonoKote. The blue painted stripe on the cowl in the review kit didn't line up well with the markings on the fuselage. All three wheels and landing gear are included in the kit. The main gear is also painted white to match the MonoKote.
Speaking of MonoKote, the fuse-lage, wings and tail feathers are all beautifully covered with white, sky blue, dark blue and red covering. Each of these assembled parts has been very well constructed, is very light, strong and perfectly straight; I couldn't find a warp in any of the parts. The parts assembled well with-out any needed modifications.
A small fibrous sheet for making hinges was included. The instructions clearly show how to cut this strip into the recommended sizes and shapes. All of the hinge slots were pre-cut in the ailerons, rudder and elevator halves and their mating surfaces. Thin CA is used to easily secure each hinge.
The wing comes as a very strong and thick one-piece unit, there is no need to join the wing halves. The top and bottom are covered with different patterns (the top is white with blue swirls and the bottom is a large red and white checker-board), making orientation very easy to keep while performing wild aerobatics. There is no dihedral in the wing so I expected there to be no difference between inverted and upright flying characteristics.
Two 24" aileron extensions are needed to reach the center section of the wing. A long string has been placed and lightly taped just inside of the servo bays. But first, connect the two aileron servos to the aileron extensions using tape or heat shrink tubing for security. Next, grab the ends of the string with a pair of needle nosed pliers and tie them to the ends of the servo extensions. Gently pull the central part of the string at the center section until the ends come through and a potentially difficult procedure is easily completed.
The horizontal stabilizer can be simply mounted using the supplied 6-32 bolts. They recommend gluing the stab with medium CA glue if you don't need to remove the stab after each day of flying. I recommend using 5- or 30-minute epoxy and the bolts in every case. A lot of stress can be generated with 3D aerobatics and the stabilizers should be as secure as possible.
The main landing gear is mounted to the underside of the fuselage with two 6-32 bolts. The friend I mentioned earlier had a problem with the gear mount on the fuselage. During a slightly bounced landing, I saw his gear tear off of the mount. This hasn't happened to mine, but still I would recommend that the mounting area be reinforced with a couple pieces of hardwood and trian-gular stock.
The engine is easily mounted with the supplied heavy duty mount. I personally am using a YS 120 engine which obviously disregards the warning about using an engine with a dis-placement greater than .91. In my case, the flying field is located slightly higher than 7,200 feet in elevation and we lose about 30% power compared to most of you "low landers."
The fuel tank is simple to assemble and installs directly behind the engine. A small piece of balsa is glued just behind the tank in order to keep it from moving. There is more than enough room to mount all of the radio components. The engine servo is placed in the included pre-cut hardwood mount which is glued into the area of the wing saddle.
Two elevator servos and one rudder servo are placed into the pre-cut bays in the rear of the fuselage with servo screws. Each of the servos require a 24" extension to reach the receiver in the main fuselage compartment.
The battery and receiver are mounted to the main fuselage area with foam and scrap pieces of balsa. In fact, I used some of the foam from the packaging to protect my battery and receiver. I also fly helicopters, so you may recognize the base loaded antennae that I used on my U-Can-Do. You can use a traditional antenna by stringing it either outside towards the tail or by mounting it inside the fuselage.
I easily mounted six servos in my ship. One servo is used for the rudder and another for the throttle. One servo is used for each elevator half and each aileron. Make sure that the paired servos are exactly the same type and brand of servo. This will help ensure comparable strength and speeds on each paired surface.
You can fly this plane with a 4-channel radio by using one Y connector with a servo reverser for the elevator halves and one for the ailerons and plug them into the elevator and aileron ports on your receiver. I decided to use two extra channels to increase the efficiency of my servos and to allow me to also dial 10% differential into the ailerons. I used a program that is included in my JR 10X radio software.
For the elevator halves, I plugged one into the elevator port and the other into AUX 3. After this, I created a program mix between the elevator channel and AUX3. When using this method, be sure to mechanically set the center points as closely as possible with the servo arms. Then use the sub trims in the transmitter to get them perfectly centered. After this, make sure that the endpoint adjustment or travel adjusts for both channels are the same.
When mounting the battery and receiver, be aware of the C.G. require-ments. The recommended C.G. for this ship is located 4-7/8" rear of the lead-ing edge for your first flights. Later, you can experiment by moving the C.G. slightly forward or rearward (up to 3/8" and 1/2" respectively) in order to improve the flying characteristics. After several flights, I ended up moving my C.G. rearward the full 1/2" from the initial recommendation in order to get my ship to hover and flat spin more easily.
Recommended control throws are outlined in the back of the manual with both high and low rates for each surface listed. For those of you who don't have a lot of experience with 3D flying, I would recommend using only the low rates for the first few flights.
Slow flight - using high rates, the U-Can-Do 3D can slow to a walk in a high alpha harrier attitude. Notice the checkerboard covering on the bottoms of the wing and stab. This really helps to keep your orientation.
As you can imagine, I couldn't wait to get to the field and fire this plane up! I couldn't ask for better weather.
My first flight was completely uneventful. The take-off roll against a light wind may have been a whole 10 yards and that was probably twice as much as I needed! Only a very small amount of right rudder was used for a nice straight track.
Once in the air, I quickly throttled back to half after remembering the warning of high speed and flutter. Trimming consisted of two clicks of down elevator and three of right aileron, the rudder was right on.
Hover - the U-Can-Do 3D is the easiest to hover airplane I have ever flown. This plane is fun!
The initial throws on low rates were perfect. In this condition, I performed several very slow passes at about 20' of altitude. I really had a difficult time getting my plane to stall. The giant thick wing along with a lot of up elevator resulted in very slow and stable flight. Once I was finally able to get it to stall, my plane barely tipped forward without any wing dropping. It immediately started flying again by itself. All controls worked well during slow flight because of the huge control surfaces.
If you are new to this type of flying, the best advice I can give you is to concentrate on your throttle management. Only use full throttle if you are steeply climbing. Otherwise, just use the minimal amount of throttle that is necessary. For example, I enter loops at half throttle and go to about 3/4 during the climbing portion. After rounding the top, drop to idle and complete the maneuver.
Knife-edged flight is absolutely solid. A small amount of aileron and elevator coupling was noted. I used two mixes to remove the coupling. I only needed about 8% of opposite aileron and 5% of up elevator mixing for both rudder deflections. The huge oversized rudder and the tall fuselage makes any knife-edged maneuver a breeze to perform.
Inverted flight only requires 4 clicks of down elevator to maintain level flight. This was of course after I moved the C.G. 1/2" back from the initially recommended point.
Rolls were true and on line with only a small 10% addition of aileron differential. I eventually decreased my elevator throw from the recom-mended 1-1/8" to just less than 1" each way to prevent the plane from stalling with immediate application of full throw. Some of you may want to dial in a little less aileron throw to make it a little more docile on your first few flights.
On high rates this plane becomes an aerobatic monster! If you don't have much 3D time, I would recom-mend that you buddy cord with one of your more experienced friends the first time you are using high rates. It can be very easy to lose your orien-tation when using high rates. With or without help, be sure to get plenty of altitude in the beginning.
This plane will do it all and more! After one week, I can comfortably perform Harriers (upright and inverted), knife-edged loops, waterfalls, walls, hover, and even multiple torque rolls. Other more traditional aerobatics are easier than ever.
The risk of learning 3D with the U-Can-Do 3D is very low considering the kit price and it only takes about three evenings to complete. To say the least, I am extremely pleased with this airplane. I have not been able to find any bad tendencies with this terrific design.
This plane lives up to its name with flying colors and you certainly can't beat the bang for your buck. Pick one up and increase your flying abilities quickly and easily with the hugeU-Can-Do 3D.
Photos by Bob Motazedi. Reprinted with permission.
September, 2004 R/C Modeler Magazine
Editor: Patricia Crews