Great Planes Bird of Time EP Sailplane ARF

Written by Terry Dunn Ready for long, relaxing flights? Product Review As seen in the May 2018 issue of Model Aviation.

Specifications

Type: ARF electric glider Wingspan: 118 inches Wing area: 1,050 square inches Length: 49 inches Radio: Futaba 14SG 2.4 GHz transmitter; Futaba R617FS receiver; Futaba S3010 high-torque ball bearing servo; Futaba S3154 digital micro servo Components Electric power system; three- needed to complete: plus-channel radio with one standard servo and one micro servo; basic assembly tools Minimum flying area: Club field Price: $219.99 Power system: Great Planes RimFire .32 brushless motor; 13.5 x 7 folding propeller (included); Castle Creations Phoenix Edge Lite 75 ESC; Flight Power FP50 4S 3,600 50C LiPo battery Power output: 53.8 amps; 785 watts Power loading: 168 watts per pound Flying weight: 4.7 pounds Wing loading: 10.2 ounces per square foot Duration: How long have you got?

Pluses

• Great styling. • Super gliding performance. • Powerful climbs.

Minuses

• Some building challenges. • Few energy-management tools.

Bonus Video

Product Review

With its classic, curvy styling and distinctive wing profile, the Bird of Time is one of the most recognizable RC models around. But this airplane is more than just a pretty face. The Bird of Time was originally designed as a competition glider, which explains its low-drag fuselage, thin airfoil, and full-flying elevator. Throughout the years, countless Bird of Time models have been built from plans, kits, and ARFs. Many of those airplanes were modified to use an electric motor and folding propeller on the nose. Electric sailplane fans can now put away their cutting wheels and sanding blocks. Great Planes recently unveiled the Bird of Time EP. This variant of the company’s Bird of Time ARF is factory equipped for electric power. The Bird of Time EP features a fiberglass fuselage with a firewall that accepts a brushless outrunner motor. A folding propeller with an integrated spinner is included. You’ll have to supply the motor, ESC, and battery to round out the power system. The aircraft’s characteristic wing has a huge span of 118 inches. It is a built-up balsa and hardwood structure that breaks down into three pieces. The elevator and rudder are built up and factory covered as well. Despite the model’s substantial size, it requires only a three-plus-channel radio with two servos.

The Bird of Time EP is a simple, but elegant powered glider that is perfect for enjoying relaxing flights on calm-weather days.

Inspecting the Bird of Time EP

My inspection of the kit was mostly positive, but I did find some minor workmanship-related blemishes. I thought that the fuselage was well molded, nicely painted, and appropriately sturdy. The wing panels felt lightweight, yet strong. A few areas in the MonoKote covering had poorly adhered seams. I was able to tidy them up with my covering iron. I also spotted a few “pimples” in the covering which hinted that the underlying balsa framework had not been adequately sanded. This kit includes two manuals. One is for the pure glider version of this ARF. The other is an addendum that notes specific steps to add or delete for the powered variant. It’s a bit cumbersome to seesaw between the two manuals. After you factor in the additional online-only addendum, things can get a little clumsy. A single EP-specific manual would be a helpful update. This is not the kind of ARF that builds in a single afternoon. Although there is not much to do, the assembly steps often demand precise, careful actions. I don’t think that any of the tasks are challenging for experienced modelers. You just want to give yourself plenty of time to complete them accurately.

The Bird of Time EP includes prefabricated balsa wing panels and a fiberglass fuselage that is ready to accept a brushless power system.

Assembling the Bird of Time EP

The first assembly step is to construct two dihedral braces that join the outer wing panels to the center section. Each of these beefy components is made by sandwiching two plywood parts between thick aluminum plates. Although it isn’t mentioned in the manuals, the plywood parts in my kit were two different thicknesses. Make sure that each brace gets one thick and one thin plywood piece. As suggested in the manual, I used 6-minute epoxy when laminating the dihedral braces. I think that the additional working time of 15- or 30-minute epoxy would have been helpful. I used several clamps to hold the parts firmly in place until the epoxy cured. I chose to permanently glue the dihedral braces to the center wing panel. I also rounded the exposed tips of the antirotation pins to ease panel alignment during field assembly. My assembled wing has some minor gaps at the panel joints, but they are nothing to be concerned about. I used several pieces of clear Scotch tape to hold the panels together.

Stout dihedral braces are constructed by laminating aluminum and plywood components with epoxy. Take your time to ensure that the parts are properly aligned.

A Futaba S3010 high-torque standard servo fits perfectly in the servo tray beneath the wing saddle. It actuates the rudder via a long pushrod. The full-flying elevator is actuated by a Futaba S3154 digital micro servo located at the base of the vertical stabilizer. Although small, the S3154 has plenty of torque for this application.

The full-flying elevator is actuated by a digital micro servo, located at the base of the vertical stabilizer.

The manual outlines a combination of hardwood blocks, servo tape, and screws to hold the elevator servo in place. I decided to forego that method. After scuffing and cleaning the mounting area and servo case, I glued the servo directly to the airframe with 6-minute epoxy. My Bird of Time EP is powered by a RimFire .32 brushless motor, Castle Creations Phoenix Edge Lite 75 ESC, and a Flight Power four-cell 3,600 mAh LiPo battery. Space in the motor/battery compartment is tight, so I planned my equipment layout to make the best use of the available space. I also wanted to get the battery as far forward as possible to avoid any need for nose weight. I mounted the RimFire .32 to the firewall with the motor wires emerging toward the bottom of the fuselage. The ESC is mounted at the rear of the battery tray. In fact, the ESC capacitors protrude rearward under the servo tray. Motor wires from the ESC are routed beneath the battery tray. The battery leads from the ESC emerge upward though the servo tray and forward into the battery compartment. To fit the Deans Ultra Plug through the servo tray, I had to slightly enlarge the forward lightening hole. The battery is placed just forward of the ESC. I replaced the kit’s two-piece hook-and-loop strap with a single length of double-sided hook-and-loop tape. Using the arrangement described, my model did not require any nose weight to balance at the suggested center of gravity (CG). I actually have some latitude with which to adjust the CG slightly forward or aft. I have to be careful that I do not place the battery against the rotating portion of the motor.

The author was able to arrange all of the necessary components in the battery bay to fit cleanly and avoid adding any nose weight.

The kit includes a 13.5 x 7 folding propeller that has an integrated spinner and 5 mm propeller adapter. This assembly fits the motor shaft perfectly and blends with the shape of the fuselage. I made sure to balance the propeller before installing it on the model. I noticed a significant gap between the spinner’s backplate and the firewall when the propeller adapter was fully seated. Shortening the motor shaft was not a solution because the pan-head screws holding the motor to the firewall would have interfered with the spinner. I decided to fill the gap with a ring cut from a scrap piece of sheet foam. I glued the ring to the firewall using Foam-Tac contact adhesive.

The gap between the spinner and firewall was filled by adding a ring made of thin foam sheet.

The fuselage has air inlets on either side of the motor, but no exit holes. Cooling has not been an issue while flying in winter. I plan to cut out an exit hole behind the wing mount to ensure that the electronics stay cool during the summer. I connected the servos and ESC to a Futaba R617FS receiver linked to my 14SG transmitter. With only three channels, radio setup is a snap. I had to expand the elevator travel to 130% to get the suggested high-rate movement. It is necessary to activate the brake function on the ESC to halt the propeller and allow the blades to fold back while gliding.

The radio bay beneath the wing saddle houses only the rudder servo and receiver.

Flying the Bird of Time EP

Although the Bird of Time EP is a large model, field assembly is simple. The wing panels slide together easily and there are no servo leads to worry about. Two bolts fasten the completed wing to the fuselage. There is also ample access to the battery compartment. All you have to do is slide the canopy forward to release the attachment pins. A hand launch gets the Bird of Time EP airborne. The power system generates plenty of thrust, so there is no need for full throttle or a Hail Mary throw when launching. I typically use approximately half throttle and give the airplane a horizontal toss into the wind. There’s nothing to it. The manual mentions that the airplane will tend to pitch up under power. That is definitely true! If you launch with heavy throttle, you might find that the Bird of Time EP has gone vertical before you can even get your hands back on the transmitter. That’s okay because the airplane will continue to climb this way if you want it to. I have considered adding a throttle/elevator mix to tune out this behavior. However, I think it is easy to correct with stick inputs now that I know what to expect. Depending on your departure angle, the Bird of Time EP could get to gliding altitude within a few seconds. You won’t have any trouble spotting that big wing, but the solid white underside is sometimes difficult to orient. After a few flights, I added three stripes to the bottom of the port wing using 2-inch-wide colored packing tape. This quick tweak really helped improve visibility. I’ve been flying the Bird of Time EP in winter conditions—often in below-freezing temperatures. Although there might not be many thermals around, the airplane still maintains altitude well. The glide is flat and flights are long. Each battery charge is good for numerous climbs to altitude. The full-flying elevator does not have much throw, but it provides plenty of pitch authority. The rudder is huge and effective. I set up my model with the suggested dual rates. I tend to fly almost exclusively with high rates. The control response is positive, but not twitchy. The motor is not only for climbing. You can dial back the power and cruise around on the deck. The Bird of Time EP behaves like an overgrown park flyer. I’ve done a few loops with the Bird of Time EP. That is the extent of the aerobatics that I will attempt. It might be capable of more, but this airplane is in its element with a smooth and gentle touch on the sticks. The polyhedral wing makes for stable flight. I’ve done circuits above the field using nothing but rudder trim for control! The flip side to this is that the airplane is somewhat sensitive to wind. You’ll want to save this one for days with single-digit wind speeds. When it’s time to land, you will find out just how aerodynamically clean this design is. It simply does not want to stop flying. There are no spoilers or flaps to help bleed off energy, nor are there ailerons to pair with the rudder for a sideslip. Be sure to set up a long approach. I’ve found that the propeller can be used as an air brake to help manage energy. It just requires precise inputs. With my setup, one click of throttle kicks out the propeller blades and slows the airplane, but two clicks of throttle produce no obvious effects. The airplane climbs with three clicks! The rudder and elevator remain effective throughout the landing. Achieving a smooth, sliding touchdown poses no challenges. A protrusion built into the bottom of the vertical stabilizer helps protect the rudder during landing. Make a mental note to check the rudder and hinge every so often.

Final Approach

A large, powered glider such as the Bird of Time EP could seem intimidating to some pilots. Although this ARF does require attention to detail during the assembly, I think that most modelers will have no trouble completing it. The aircraft’s broad girth breaks down into manageable components that make transporting and storing it easy. The stylish lines of the Bird of Time EP belie its fundamental simplicity. This model launches easily, and quickly reaches soaring altitude. It then transforms into a docile floater capable of long, relaxing flights. —Terry Dunn [email protected]

Manufacturer/Distributor:

Tower Hobbies (800) 637-4989 www.towerhobbies.com Great Planes (217) 398-8970 www.greatplanes.com

Sources:

Futaba (217) 398-8970 www.futabarc.com Beacon Adhesives (914) 699-3400 www.foam-tac.com Castle Creations (913) 390-6939 home.castlecreations.com Flight Power (217) 398-8970 www.flightpowerbatteries.hobbico.com