Fly RC Magazine WE LIVE RC
Relive Aviations Golden Age with this Timeless Classic
For pilots and dreamers around the world, nothing speaks to the glamour of flying like a classic open cockpit biplane from Aviations Golden Age. And when it comes to classic open cockpit biplanes, those known by Waco sit proudly at the front of the line. The choice of most any pilot who could figure a way into the 
cockpit back in the 1930s, surviving Waco aircraft are still highly sought after and command a premium price whenever they come up for sale. So desirable are the originals, a handful of enthusiasts founded Waco Classic Aircraft and reintroduced the Waco YMF-5 in the mid 1980s as a new production aircraft based on the original 1935 FAA Type Certificate. It is their latest edition, the YMF-5D that Great Planes has faithfully replicated.
The IMAA-Legal Great Planes Waco is 1/5 scale and spans 72 inches. This is a great size that presents well at the club field and offers excellent performance yet doesnt demand an exotic engine, servos or transportation. Yes, this is a premium model that you can still take out and fly regularly.
TIPS FOR SUCCESS
I first read through the manual carefully, looking for anything that might trip me up as I went along. I also kept it close at hand during assembly, noting anything I wanted to remember for my review. Looking back, I found I wrote down almost nothing. You can download the manual, so I will highlight the few points that I did note instead of stepping through the complete process.
Assembly begins with installing the aileron servos and then mating the wing panels. The four aileron servos mount internally on hatch plates. This hides the servo within the wing and also aligns the servo rotation with the hinge axis, creating the ideal linkage geometry. While using a pair of servos and aileron slave struts would have been more scale, separate servos are much easier every time you get to the field. Joining the wing panels comes once you have all the servos in place. Unless, that is, you are looking to make extra work for yourself as I did.
I made two modifications while assembling the wings. First I sprayed the plated strut brackets and nylon control horns using Rustoleum enamel. Next the manual directs you to bring the two extension leads out of the lower wing and connect them to a y-harness wire tied to the cabane struts. Instead I cut the ends off the extension leads just outside of the wing and soldered the wires together, effectively creating one giant custom y-harness inside the upper wing. I now have only one lead to connect during assembly and a single lead at the cabanes.
Great Planes includes a nice plywood bracket that screws to the cabane struts when the upper wing is not installed. This protects the struts and also provides a great handle and storage hook for the fuselage.
My heavy handedness bit me as I moved on to the fuselage. I heard a faint popping sound as I reached for the landing gear in the box, and before I realized it I had pinched both of the gear leg fairings sufficiently to split their leading edges. The gear features a robust aluminum strut with a fiberglass fairing around it, but the fairings are hollow. The struts do not support the fairings and I quickly learned that the landing gear is not a handle. Close inspection now shows faint hairline cracks that I closed with 30-minute Z-Poxy.
You need to cut 1/4 inch from each axle before installation. I chucked them in my Sherline lathe and shortened them with a parting tool. It took no longer than using a Dremel and felt more right. I waited to install the wheels and axles during the final assembly steps so it wouldnt roll off my bench.
The horizontal stabilizer mounts using two aluminum tubes. Be sure to dry assemble the tail to check alignment with the lower wing and fuselage before mixing any epoxy. Masking tape held everything in place while the epoxy cured.
The rudder does not come mounted, so again test fit everything before gluing. My rudder was not grooved to accommodate the tailwheel wire, so I made a few swipes with a #11 blade to create the needed clearance then sealed the wood with thin CA.
Note that there is a laser cut plywood plate in the box that isnt mentioned in the manual until step six of the final assembly. It is the battery tray and glues in place just ahead of the servos.
POWER CHOICES
The manual details both glow and gasoline engine installations, and no doubt some will opt for electric power. I chose the O.S. FS- 120S-E glow engine over a gasser for its lightweight, dependable power, lower vibration levels, cooler operation and realistic 4-stroke sound.
I used the adjustable motor mount included in the kit and drilled the tap holes slightly undersize before running the 8-32 tap in, to maintain maximum possible thread depth. It is nice to see standard SAE hardware. Thanks Great Planes!
When it came to hooking up the throttle servo, it was clear that the pushrod could foul the tank. This was easy to fix by reversing the throttle arm on the carburetor. This isnt mentioned the manual, but it is shown.
I used different color fuel tubing for the vent, fill and drain lines when prepping the tank. Remember the fuselage will be upside down on your bench while installing the tank. Labeling it will help keep plumbing properly aligned and save tearing the model apart at the field when you finally figure out why your engine doesnt run right. Finally, I extended both the choke and needle valve out the bottom of the boot cowl.
FITTING THE COWL
This was the closest I came to frustration with this model. The fiberglass cowl is beautifully molded and painted. It mounts with two plywood rings, one bolts to the fuselage boot cowl, the second is bonded into the cowl. Unfortunately both rings are exactly the same diameter. The mounting ring needs to pass cleanly through the rear opening and mine did not. I ended up sanding about 1/16 inch off the ring all around before I could get the cowl to pass smoothly over it. It wasnt a big deal, but I wonder why it wasnt cut smaller. Dont forget your locktite on the cowl bolts.
Great Planes includes a plywood jig that you need to stack up, glue together, then slide over the crankshaft to properly align the cowl front while you locate the engine cutouts and bond in the cowl ring. Think of a very short top hat. The rear flange (hat brim) keeps the cowl from moving too far aft. While that all sounds great in practice, again it did not quite work as advertised. The rings and adapter disk were larger than the cowl cutout. Unfortunately I didnt discover this until I had bonded on the flange and needed to break it free. I secured the remainder to a scrap of wood clamped to my disk sander table and reduced it to clear the cowl opening. After rebonding the flange ring I was back in business. The cowl does need slight trimming for the valve cover and exhaust manifold when using the O.S. 120, but nothing out of the ordinary.
The last step for my engine installation was adding a Sonic-Tronics glow driver. I secured the box right behind the fuel tank using heavy duty Velcro and installed the charge jack and monitoring LED in the forward cockpit next to the radio switch and charge jack.
DRESSING IT UP
The dummy engine is a very nice inclusion in the kit and it really looks sharp after adding a little paint and the pushrod tubes. The manual recommends bonding the dummy into the cowl, but the gap was larger than I wanted to bridge with glue. I cut pieces of scrap pine, securing them to the dummy engine between the rocker boxes using servo mounting screws. I then roughened up the inside of the cowl with 80-grit and bonded these blocks in place using 30-minute Z-Poxy. Once cured, I unscrewed the dummy engine and reinforced each block with a fillet of epoxy and milled cotton fiber. Finally I painted the blocks and inner cowl using a foam brush loaded with Nelson Hobby black paint. I was even able to save the brush for later use, as the Nelson Hobby paint cleans up with water and is fuel proof when dry. Nice stuff, that paint.
I used Pacer Canopy Glue as directed to secure fairings for the landing gear and wing, as well as the windscreens and headrest and the rest of the assembly went as per the manual.
In addition to painting the strut plates and dummy engine stand offs, I also added a few other personal touches. I chose a 12-inch heavy duty Hitec servo extension for the run to the upper wing, simply to match the color scheme. It is a little thing I know, but it all adds up. I also gave a little flourish to the forward cockpit door and luggage hatch. Instead of using the recommended panel line pen, I cut pieces of 1/64 plywood to shape and covered them with Cub Yellow Monokote. I added the stock latch and hatch decals and finished with matching stripes of red and black Monokote.
My most obvious addition is the cockpit combing. The kit comes with a raw cockpit edge and it is up to you to dress it up as you see fit. I opted for faux black leather and red thread, again to compliment the trim scheme. DAP Weldwood contact adhesive secures the combing and the thread is just for show.
The interplane struts look nearly the same right side up and upside down, but if you have to force anything to line it up, you have the strut reversed. Once you get them set properly, identify the top of the struts with a quick dab from a sharpie marker. Also, spread a moving blanket out on the ground or the field worktable and assemble your model over that. Metal hardware doesnt bounce off the blanket like it does plywood, and you should be able to find anything you drop on that blanket. Good luck looking in the grass.
AIRBORNE
The day scheduled for my first flight dawned clear, calm and warm and by the time I got out to the field that afternoon not much had changed except the position of the sun. I hadnt run the new O.S. yet, so I bolted on the lower wing and ran half a tank through the engine. I would have gone more, but by that point I had a solid top end pull, a tick-over idle and smooth transition. I richened it a click or two for additional cooling, finished assembly and topped off the tank. It was time.
As before, the O.S. started instantly and settled into its rumbling purr. As I taxied out across the grass I couldnt help but add in a few s-turns for visibility, then let it tick over for a few seconds after lining up. The Waco was rolling shortly after I eased the stick forward, and a couple of quick taps of rudder kept it straight. Long before I got near full revs she had taken wing and was climbing nicely. I had been holding a little back pressure to keep from nosing over on the take off run and as I relaxed the stick I realized I needed some trim. 8-10 beeps later all was good with the world and I pulled back power to line up for my first pass over the runway. The only thing missing, beyond the wind in the flying wires I havent added yet, was me, sitting in the cockpit as it roared by. Pulling up for a hard climb, I waited as it eventually slowed then kicked it over in a stall turn and came right back down the slot. It didnt take much imagination to turn the sound of that O.S. into a big old Jacobs.
Climbing back out my mind started flashing through passages from Budd Davissons pireps, Richard Bachs Biplane, my own first solo some 30 years ago and the precious little time I have logged in open cockpit biplanes. Theres just something about a big biplane loafing through the sky that brings it all back. I know youve read it all before “ ¦ the smell of fresh cut grass and the burgers on a grill as you float by overhead ¦ “ and while such sentiment may seem trite when flying just a toy plane, this one is fully capable of reviving those memories and emotions for a willing mind.
The O.S. is a perfect match for this airframe. The full throttle vertical climb goes just high enough before running out of steam for a gorgeous hammerhead. If you fly it over the top earlier you can dance through lazy-8s until your tank runs dry. It will easily loop and roll from level flight, but there isnt so much power that you are inclined to confuse it for a modern overpowered model of a modern overpowered airshow mount. No, a Waco is not about ripping up the sky. It is about becoming part of it and, as I was confirming, this model does that so very well.
Snapping back to reality, I decided I better check out the stall before it had to come home. Pulling the power and easing the stick back showed why so many before me have found so little wrong with a Waco. Its wings clawed at the air, keeping it aloft long after the laws of physics say it should have quit. When it finally sighed and conceded its fate, the nose and left wing both dropped slightly and it was flying again as soon as I released the stick pressure. I didnt bring much power back in, but instead let it settle into its glide and arced toward the runway. Despite the drag of an extra wing and that big cowl, the Waco carries quite well and it took several passes to find my two landings that first day out. You can see some of the action on our web site, and yeah, I did end up rolling out into the tall grass on the second landing. The Waco didnt suffer at all. No question, this is going to be a great model for summer fun, and I do believe I will soon find that sweet spot for our 285-foot club field.
SPECS
PLANE: Waco YMF-5D Biplane ARF .91
MANUFACTURER & DISTRIBUTOR: Great Planes
TYPE: IMAA-legal giant scale biplane
FOR: Experienced builders and pilots
WINGSPAN: 72 in.
WING AREA: 1384 sq. in.
WEIGHT: 13 lbs. 14 oz.
WING LOADING: 23.7 oz./sq. ft.
WING CUBE LOADING: 7.65
LENGTH: 56.5 in.
RADIO: 4 channels required; flown with Futaba 10CAG transmitter, Futaba R617FS receiver, 6 Futaba 9001 servos for flight controls, 1 Futaba 3004 standard servo for throttle.
ENGINE: .91 2-stroke, 1.20 4-stroke glow engine, or 25 – 30 cc gasoline engine recommended; flown with O.S. FS-120S-E Surpass 4-stroke
PROPELLER/SPINNER: Master Airscrew 16X8 propeller
TOP RPM: 8,200
FUEL: Byron Aero Gen 2 5% Premium 18
ONBOARD BATTERY: Hobbico LiFeSource 6.6V 1800mAh receiver battery, Sonic-Tronics Mcd466 onboard glow driver.
PRICE: $479.97
COMPONENTS NEEDED TO COMPLETE: Suitable glow or gasoline engine, 4-channel radio (minimum) with 7 standard servos. 4 servo extensions (12, 16, 16 & 30 inches) 2 Yharnesses (6 & 21 inches), switch and charge jack mounting set.
SUMMARY: Looking to give us something extra special, the team at Great Planes started with a clean sheet and created a new model that is sure to please anyone who appreciates the timeless appeal of a classic biplane.
Online Video & Wallpaper: www.flyrc.com/091107
CONCLUSION
I spent about 20 hours while assembling the Waco, with only a few minor points to quibble about, and those were immediately erased with my first lift off. You will be hard pressed to find a nicer way to get to the field and get flying than with this timeless classic. From the first bark of the O.S. through to the final roll out, the Great Planes Waco was everything I was anticipating and more. They sure got it right, all those many years ago. Just ask any pilot.
Links
Byron Originals
www.byronfuels.com, (712) 364-3165
Futaba, distributed exclusively by Great Planes Model Distributors
www.futaba-rc.com, (800) 682-8948
Great Planes
www.greatplanes.com, (800) 682-8948
Master Airscrew, distributed exclusively by Windsor Propeller Company
www.masterairscrew.com, (916) 631-8385
Nelson Hobby
www.nelsonhobby.com, (303) 670-1336
O.S. Engines, distributed exclusively by Great Planes Model Distributors
www.osengines.com, (800) 682-8948
Sherline
www.sherline.com, (800) 541-0735
Sonic-Tronics
www.sonictronics.com, (215) 635-6520
