Dynam Waco 1270mm

Written by Terry Dunn A simple and enjoyable aircraft that draws attention Product Review As seen in the February 2018 issue of Model Aviation.

Bonus Video

Specifications

Type: Semiscale electric Wingspan: 50 inches Wing area: 625 square inches Length: 38.7 inches Radio: Futaba T6L Sport 2.4 GHz transmitter, Futaba R3106GF receiver, four 9-gram servos (included) Components needed to complete: Minimum four-channel radio, 4S 2,200 mAh LiPo battery and charger, basic assembly tools Minimal flying area: Club field Power system: BM3720A 650 Kv outrunner brushless motor (included); 12 x 6 propeller (included); 40-amp ESC (included); Admiral 4S 2,200 mAh 35C LiPo battery Power output: 31.5 amps, 485.1 watts Power loading: 127 watts per pound Flying weight: 3.8 pounds Flight time: 8-plus minutes Wing loading: 14.1 ounces per square foot Price: $179

Pluses

• Nice flying qualities. • Accurate Waco styling. • Works well on grass runways.

Minuses

• Some gaps in factory-built components. • Mismatched colors.

Product Review

Foam ARFs have evolved dramatically during the past several years. Many off-the-shelf models now include novel features such as retractable landing gear, flaps, and lighting systems. Although all of those things are fun, they also make today’s average foamie a rather complex model. Sometimes it’s nice to get back to basics and fly an airplane without all of the bells and whistles. Dynam’s model of the full-scale WACO YMF-5 is one of those foam kits that is unencumbered with add-ons. Well, okay … it does have built-in lights. But every other function on this airplane is essential for flight. Sporting a 50-inch wingspan, this is a nice size model of a classic American biplane. Let’s check it out!

Assembly

The subject of my review is a receiver-ready version of the Waco that is available from Motion RC. It includes all of the necessary equipment except for a four-channel radio system and a 4S 2,200 mAh LiPo battery. Most of the model is factory built, with four micro servos and a brushless power system preinstalled. As I examined the contents of the kit, I found several things to be happy about, as well as some things that weren’t so great. On the positive side, this model is a faithful rendition of the full-scale YMF-5—an airplane that many consider to be the best-looking biplane that ever was. I find it hard to disagree. The classic styling of the aircraft translates well at this scale.

The Dynam Waco 1270mm is a receiver-ready ARF made primarily of molded-foam components.

My concerns with the kit were mostly related to workmanship issues. Several of the preassembled foam components had noticeable gaps along the seams. Additionally, the paint used on the front windscreen was much different than the color of the fuselage. My example also had several dark fingerprints in various locations. The good news is that all of those issues were purely cosmetic. The manual is printed on a single foldout sheet. Photos and text related to the assembly steps are small, but sufficient given the simplicity and level of prefabrication in this kit. I only ran into a few minor snags while assembling the Waco. I’ll explain how I overcame those hiccups in the process. One step not mentioned in the manual is attaching the two plastic windscreens. I used Pacer Formula 560 Canopy Glue for this task. Masking tape held the parts in place while the glue dried overnight. Even the low-tack tape that I used could pull paint from the foam airframe, so I was careful to avoid adhering the tape to any visible areas of painted foam. In keeping with this project’s spirit of simplicity, I used a basic radio. The Futaba T6L is about as straightforward as a 2.4 GHz six-channel radio can get. The included R3106GF receiver fits nicely between the factory-installed rudder and elevator servos. There is a lot of room in which to work and route the necessary wires.

A Futaba R3106GF receiver fits nicely between the rudder and elevator servos. There is plenty of room in which to work and route the servo wires.

The lower wing is a one-piece unit that bolts directly to the fuselage. The upper wing is assembled from two halves. It attaches to the fuselage and lower wing via some beefy struts. It takes a minimum of eight screws and nuts to attach the upper wing. Fortunately, the Waco fits in my minivan with the wings in place. Four LED lights are built into the Waco. Two are located on the leading edge of the lower wing. The others are on opposite tips of the upper wing. An included wiring harness powers these lights using an open channel on the receiver. The lights are not controlled by the radio. They are always on when the flight battery is connected. Leads for the upper lights emerge from the wing near the inner strut attachments. I routed these wires along the inside surface of the struts. I cut a slot on each side of the battery bay to allow the wires to discreetly enter the fuselage and attach to the wiring harness.

Power leads for lights in the Waco YMF-5 upper wing can be routed along the inner wing struts and into the battery compartment.

The tail feathers on my kit were significantly warped. The vertical stabilizer was bowed and slightly angled, and the horizontal stabilizer was twisted. I was able to get both parts reasonably straight by carefully flexing them into the correct shape. They’re not perfect, but close. I’ll monitor these pieces to ensure that they do not relax over time. Pushrods connect the upper ailerons to those on the bottom wing. One of my pushrods was defective and would not thread onto the included nylon clevis. I replaced both pushrods with pieces from my spare parts stash. The stock power system is built around a brushless outrunner motor spinning a 12 x 6 propeller. Dynam even includes a spare propeller. The motor is controlled by a 40-amp ESC with an XT-60 battery connector. The motor and ESC are housed within preassembled components, so you must separate the glue joints if you ever need to access to them. I powered the Waco with an Admiral 4S 2,200 mAh 35C LiPo battery. It easily fits in the battery area and is held in place with hook-and-loop tape. With the battery fully forward, I needed to add 1.5 ounces of ballast between the dummy engine and the lip of the motor cowling. You could reduce or eliminate the ballast by using a larger-capacity battery, but you might have to remove foam from the battery compartment for a proper fit. A large sheet of self-adhesive decals is provided. I selected a few that reflect a full-scale YMF-5 and applied them to the model. You might want to trim away simulated rivets, mold marks, or other protrusions that will be beneath any of the decals. This helps them lay flat on the surface of the airframe and appear more natural. I overlooked this step and later wished I hadn’t. No pilot busts are included in the kit, but an open cockpit biplane begs for at least one aviator behind the windscreen! My finishing touch for the Waco was a pilot to fill the rear cockpit, which is the proper place for a solo pilot in the full-scale YMF-5. Because this location is significantly behind the center of gravity, I knew I would need a very lightweight pilot. I chose the 2.5 x 3.25-inch pilot from Park Flyer Plastics. The figure comes in three vacuum-formed pieces that must be assembled and painted. Don’t let that intimidate you. The process was easy and fun. Best of all, the completed pilot weighs just 4.2 grams! I trimmed the figure to the height I wanted and glued it in place with canopy glue.

Futaba T6L Sport

The Futaba T6L is a no-frills radio that provides a solid 2.4 GHz link and six channels on a budget. In addition to the four channels commanded by the joysticks for basic flight controls, the T6L has a two-position toggle switch and rotary knob to control auxiliary functions. All of the components are housed in a full-size case, so this transmitter has the same look and feel of other Futaba radio systems. The simplicity of this radio is reflected in the cleanliness of its layout. Along with the previously mentioned joysticks, switch, and knob, only the power switch and trim sliders are visible. There are no additional control devices to be found—even the antenna is hidden. This radio system does not have dual rates. It’s a feature I use a lot with my other radios, so I expected to miss that capability when flying the Waco. It turned out to be no big deal. After the first few flights, I didn’t even think about it anymore.

The Futaba T6L is a clean and uncomplicated six-channel budget radio.

Power is provided by four AA alkaline batteries. The battery compartment is shared with a panel of eight DIP switches. Six of these switches control servo reversing. The remaining two switches are used to activate the three built-in mixing options. These mixes include elevon, V-tail, and flaperon. The rear of the case also has a trainer port, allowing the T6L to be used with a buddy-box system or computer simulator. The included R3106GF receiver is a small, lightweight unit that uses a single antenna. It should fit easily into most park flyer-size models. This receiver has a preprogrammed failsafe setting that brings the motor to idle if it loses connection with the transmitter. A simple model such as the Dynam Waco deserves an equally simple radio to control it. The T6L definitely fits the bill. The two extra channel controls and mixing options allow this radio to command a variety of models, including flying wings, V-tail aircraft, and yes, even airplanes with retracts and flaps. The T6L Sport is available from Futaba for $89.99.

Flying the Waco

My ready-to-fly Waco weighed in at roughly 6 ounces more than the stated weight. I wasn’t concerned about that because the wing and power loading values looked good. With all of the pushrods located in the outermost holes of the control horns and servo arms, the control throws were close to the recommended values. I’ve been flying the Waco from a grass runway. I was concerned that the wheel pants would cause problems on this surface, but it has not been an issue. I can taxi, take off, and land with no complications. This model has enough power to get off of the ground with a short takeoff roll, but it looks so much better with a more refined approach. If you gradually feed in power, the tail will lift and posture the biplane on its main wheels. A little back pressure will have it airborne and climbing away. The power system is a good match for this airframe. It has good climbing ability, so tall loops and graceful hammerheads are possible. Full-throttle passes do not exactly set the sky on fire, but that’s okay because this is a Waco. Why would you ever be in a hurry when flying one? Aileron response is quite good. Other pilots have told me that the roll response is too sensitive for them. They could always reduce the throws by moving the pushrods to an inner hole on the servo arms, but I like the roll rate where it is. I was surprised by the rudder’s effectiveness. There is plenty of authority for casual knife-edge flight and fun sideslips. Combine rudder with a jab of elevator and you will be rewarded with a quick snap roll. My first several flights with the Waco took place on blustery days. This foamie handles the wind quite well. I never felt as though the breeze had more command of the airplane than I did. With that stated, I definitely prefer flying the Dynam Waco on calm days. My favorite flights with this model have involved leisurely circuits around the pattern—shooting touch-and-gos as the sun set off the west end of the runway. With a mix of aerobatics and cruising, the 2,200 mAh battery routinely provides flights lasting at least 8 minutes. It’s best to maintain a few clicks of throttle on final approach. I prefer to bring the Waco in on its main wheels and let the tail settle on its own. This yellow biplane really looks at home touching down on a grass strip.

Final Approach

The Dynam Waco 1270mm is an uncomplicated model that offers the simple joys of stick-and-rudder flying. What it lacks in fancy gizmos, it more than makes up for with nostalgic styling and solid flight performance. Although I had some reservations regarding the fit and finish of the prefabricated components, I eventually realized that these blemishes are only noticeable up close. I’ve had numerous people tell me how great the Waco looks—both on the ground and in flight. In fact, I can’t recall ever having an ARF that received so many unsolicited compliments. This airplane is a crowd-pleaser and a pilot pleaser.

Even with wheel pants in place, the Waco works well on the grass runway at the author’s club.

—Terry Dunn [email protected]

Manufacturer/Distributor:

Motion RC (224) 633-9090 www.motionrc.com Futaba (217) 398-8970 www.futabarc.com

Sources:

Park Flyer Plastics (817) 233-1215 www.parkflyerplastics.com