Old School Model Works Sky Ranger 40

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Written by Terry Dunn Laser-cut kit has ’70s appeal Product Review As seen in the October 2018 issue of Model Aviation.

Bonus Video


Type: Glow/electric laser-cut kit Wingspan: 60 inches Wing area: 527 square inches Length: 42.8 inches Radio: Futaba 14SG 2.4 GHz transmitter; Futaba R617FS receiver; four Hitec HS-225MG mini servos Components needed to complete: Power system; radio gear; pushrods; wheels; shop tools; glues; covering Minimal flying area: Club field Price: $119.95 Power system: E-flite Power 32 brushless motor; APC 12 x 8E propeller; Graupner 70-amp ESC; Flight Power 4S 3,300 mAh 25C LiPo battery Power output: 54.5 amps, 850 watts Power loading: 188 watts per pound Flying weight: 4.5 pounds Wing loading: 19.7 ounces per square foot Flight duration: 7-plus minutes


• Classic styling. • Precise fit of laser-cut parts. • Sporty, aerobatic performance.


• Weak hatch magnets. • Limited battery positioning. • Light rudder authority.
The Sky Ranger 40 is a sporty, low-stress performer.

Product Review

Everyone knows that the RC airplane market is dominated by ARFs. It is easy for those of us who enjoy building to feel neglected, but there are still numerous options put forth by a cottage industry of kit producers. In fact, the latest generation of laser-cut kits is better than ever! A new company in the kit market is Old School Model Works. The company’s Sky Ranger 40 is a modern airplane with classic styling. This open-cockpit sport airplane is reminiscent of the hand-built models of yesteryear. In this review, I will cover the basic aspects of building the Sky Ranger 40. Of course, no review would be complete without a rundown of the model’s flight performance!

Building the Sky Ranger 40

The Sky Ranger 40 includes most of the components that you will need to make a flying model. There is a selection of laser-cut balsa and plywood parts, as well as sheet and strip stock. Prebent main landing gear and the necessary hardware are also included. Assembly is guided by a printed manual and two sheets of full-size plans.
The Sky Ranger 40 kit includes laser-cut components, full-size plans, and a selection of hardware.

In addition to the basic tools and adhesives required for a kit build, you must also supply the wheels, pushrods, covering, power system, and radio gear. Glow fliers will need a .40 to .45 engine. Those who prefer electric power should choose a system with at least 700 watts of power. The radio demands are basic. A minimum four-channel system with standard servos will work fine.
The author used a Futaba radio system with Hitec servos to control the Sky Ranger 40

Construction begins by building the left and right wing panels over the plans. The overall wing design is quite traditional, but the assembly process has unconventional elements. A bottom spar is secured to the work surface and ribs are added, starting at the wingtip. What’s unique is that two shear webs are glued to the inboard side of each rib before it is glued to the spar. This technique produces a rigid wing structure early on, but it does demand extra care to maintain proper alignment. The dihedral brace consists of a single piece of light plywood sandwiched by balsa. The manual instructs you to epoxy these parts to each other while concurrently mating them with the wing. I had a little trouble managing the multiple layers when dry-fitting everything together, so I went off script and assembled the dihedral brace separately before using it to join the wing halves. Although the fuselage looks as though it has a complex truss structure built of sticks, it is actually a simple sheet assembly. Light plywood is used in the forward half, while the rear is balsa. It all goes together quickly.
Experienced builders will have no trouble framing the Sky Ranger 40. A unique aspect of assembly is that shear webs are attached to the wing ribs before being joined to the spar.

The curved topside of the fuselage uses 1/8-inch balsa stringers. Knowing how clumsy I can be, I knew it would only be a matter of time before I snapped one (or more) of those stringers while handling the model. I beefed things up by substituting 1/8-inch basswood sticks. A magnetically secured hatch provides access to the battery/fuel tank area. The included magnets did not hold the hatch as securely as I wanted. I overcame this by adding a 1/4-inch Hatch Latch Kit from Retro RC. The tail feathers are made of 1/4-inch laser-cut balsa sheet. They were easy to assemble correctly and sand to shape. The manual does not define any specific method for configuring the control setup on the rudder and elevator. Pushrods are not provided, so you will have to make your own. I used carbon-fiber tubes with 2-56 threaded rod on both ends. I’m sure that hardwood dowels would work as well. Finding a suitable location for the elevator control horn was simple. The rudder proved to be more challenging. My solution was to create an adjustable control horn of sorts. The tail wheel wire is connected directly to the rudder. I attached a 3/32 wheel collar to this wire near the midpoint of the fuselage. I replaced the collar’s setscrew with a 1-inch long 4-40 bolt. A threaded nylon linkage on the bolt allows it to connect with a clevis on the rudder pushrod. With this configuration, the rudder servo provides direct control of the rudder and tail wheel. I wanted wheels that would accentuate the nostalgic lines of the Sky Ranger 40. Du-Bro’s 1/8-scale Vintage Wheels (3.5-inch diameter) did the trick. I drilled the hubs with a 13/64 drill bit to fit the landing gear wire. I used a lightweight 1.25-inch diameter foam wheel on the tail. A model such as the Sky Ranger 40 is ripe for many color schemes. I wanted to keep things simple and clean. Most of the model is covered with white UltraCote. The fleur-de-lis graphics are hand cut from UltraCote trim sheet. The kit includes parts for an optional headrest behind the cockpit. Assembling and sanding the parts to shape were both quick tasks.
The optional headrest was built, sanded, and painted. It provides a nice cosmetic accent.

Although I’m sure that some of you iron-on wizards could do it in your sleep, covering the curvy headrest was a real chore for me. After three failed attempts, I turned the iron off and switched to paint. I sealed the wood with water-based polyurethane, then primed and painted it with Krylon spray paint. I like the result. I applied a standard wood stain to the light plywood sides of the fuselage. Two coats of water-based polyurethane over the stain provided a nice finish. It helped to lightly sand the wood with 200- or 300-grit sandpaper following the stain and first coat of polyurethane. Pilots who fly with nitro power will want to make sure to choose fuelproof products. An open-cockpit model looks best with a pilot figure in place. I found a suitable one in my spare parts bin. Spare light plywood was used to create an instrument panel and false floor to further dress up the cockpit area. All of the control surfaces are actuated by Hitec HS-225MG servos. I used a Futaba R617FS receiver linked to a Futaba SG14 transmitter. My radio programming reflects the simple nature of the Sky Ranger 40. It’s a snap to set everything up. The battery fits nicely in its compartment, but there is little room to shift it forward or backward. That could be an issue for some builders when trying to balance the model. I lucked out and mine balanced perfectly with the standard battery location. No ballast was necessary.
The flight battery fits well, but there is little room for adjustment. Note the hatch retention magnets that were added in each corner.

Although I did not have any notable hiccups while building the Sky Ranger 40, I do not think this kit is suitable for first-time builders. Facets such as control setup and engine mounting are left completely up to the builder. You’ll need to be competent with those skills.

Flying the Sky Ranger 40

The model’s landing gear has a wide stance and plenty of ground clearance for the 12-inch propeller. Combined with the steerable tail wheel, the Sky Ranger 40 has solid ground handling. I found that gradual application of power helped me to track straight during the takeoff run. I mounted my motor with 3° of right thrust. The Sky Ranger 40 still demands some corrective rudder input, especially when you first start rolling. The model quickly achieves flying speed and takes to the sky with authority. Aileron authority is excellent. Rolls are crisp and tight. I am surprised by how cleanly the Sky Ranger 40 stops rolling as soon as I neutralize the stick. It’s instantaneous. The elevator is quite effective as well. This airplane happily performs big or small loops. Inverted flight requires only a hint of forward pressure. A quick yank back on the stick, coupled with rudder, produces a respectable snap roll. I sometimes yearn for better rudder authority with this model. It’s fine for coordinated turns, sideslips, and other common maneuvers, yet rudder-heavy moves such as stall turns, wingovers, and knife-edge flight, are slightly soft for my taste. My model balanced at the suggested location, which I think is perfect. Stalls are very gentle. The airplane starts flying again as soon as back pressure is released. You have to get quite heavy-handed on the controls to coax the airplane into a spin. Again, recovery is immediate. I didn’t expect this model to be very fast because it has a relatively thick airfoil. Much to my surprise, the Sky Ranger 40 can really boogie when you firewall the throttle! My power system offers great climb performance. I guess that’s what happens when your power loading approaches 200 watts per pound. A significant portion of my flights are spent at 1/2 to 3/4 throttle. That’s more than adequate for cruising and aerobatics. Full power is reserved for an occasional jolt of adrenaline. Flights lasting 7 minutes or longer are normal with the mixed flying style that I prefer. The Sky Ranger 40 is one of those models that is easy to land, but somewhat challenging to land well. Achieving a gentle, YouTube-worthy arrival demands a little work. Many of my attempts to bring the Sky Ranger 40 in on the main wheels have resulted in bouncy rollouts. I consistently have the best luck when I go with a full-stall, three-point landing. Overall, the Sky Ranger 40 is a well-rounded, low-stress sport airplane. It is fun to fly and doesn’t hide any unwanted surprises. If you’re a fan of “Stik” models, you will feel right at home flying this aircraft.

Final Approach

The Sky Ranger 40 is a great specimen representing the current state-of-the-art in laser-cut kits. It has a well-designed airframe that fits together nicely. Modelers who have built a kit or two should have no trouble building this airplane—and have fun doing it. The completed model is a nimble performer with clean, retro styling. —Terry Dunn terrydunn74@gmail.com


Old School Model Works (513) 755-7494 www.oldschoolmodels.com


Du-Bro (800) 848-9411 www.dubro.com E-flite (800) 338-4639 www.horizonhobby.com Futaba (217) 398-8970 www.futabarc.com Graupner USA (855) 572-4746 www.graupnerusa.com Hitec RCD (858) 748-6948 www.hitecrcd.com Landing Products Inc (530) 661-0399 www.apcprop.com Retro RC (248) 212-9666 www.retrorc.us.com

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