For visitors to my website, my “Build of the Month” (BOTM) Series was created to help those who are trying to get started in building their own Radio Controlled (RC) Model Aircraft.

  "Aerofred.com" and "Outerzone.co.uk" are two of my favorite web sites to obtain free RC model airplane plans for my new builds. Additionally, they like to post images of Builder's models, and both sites have posted my RC model images and build descriptions under the heading of the associated aircraft model. Other good sources for free plans are: "Hip Pocket Aeronautics Builders' Plan Gallery", "Vintage & Old-Timer RCM Free Plans", "James Hatton Blog Free Plans and Articles", "Hlsat Blog RCModeler Free Plans and Articles", and "Don Dewey Memorial RCM Plans Collection."

  If you are currently not an active builder, and you would like to be, my BOTM Series is a great place to start. If you have an RC model aircraft that you would like to see featured in this section or feel others may find interesting, please let me know and I will make every attempt to find scratch build plans, photos, and maybe even a published build article, which I will then post in a future BOTM edition. Just send me an email @: Build of the Month.

Build of the Month Series - March 2026 Edition

  I hope you enjoyed last months BOTM Edition on the Sky Ranger 40. If you have an RC model that you would like to see featured in this section or feel others may find interesting, please let me know and I will make every attempt to find scratch build plans, images, and maybe even a published build article, which I will then post in a future edition. Just send me an email @: Build of the Month.

  Ok, now lets see what I have for the month of March 2026. Since I first started my BOTM Series back in August 2023, I have not selected a military aircraft from the “post WW-II” period. So, how about something from that period and lets add that it must have twin engines, or more. Additionally, something that has several plans for not only a balsa and ply or foam scratch build, but also a selection of 3D printable models since I have jumped into that method of RC model builds. Given these requirement, this month features the OV-10 Bronco, a military aircraft produced by North American Rockwell that is easily recognized by its combination of the twin booms, with a horizontal stabilizer that connects them.

Images Source: Wikipedia OV-10 Webpage, and Cutaway Drawings OV-10 Webpage.

  The North American Rockwell OV-10 Bronco is an American twin-turboprop light attack and observation aircraft that was developed in the 1960s. Purpose-built for for counter-insurgency (COIN) combat, Forward Air Control (FAC) and intended to fly off unimproved short fields with its high lift narrow wingspan wings. The Bronco performed observation, helicopter escort, armed reconnaissance, utility light air transport, and limited ground attack. The Bronco has also performed aerial radiological reconnaissance, tactical air observation, artillery and naval gunfire spotting, airborne control of tactical air support operations, and front-line, low-level aerial photography. In recent times, Broncos continue service as fire fighting aircraft and flying specialized evaluation missions against ISIS.

  The OV-10 has a central nacelle containing pilots and cargo, and twin booms containing twin turboprop engines. The visually distinctive feature of the aircraft is the combination of the twin booms, with the horizontal stabilizer that connects them. The aircraft's design supported effective operations from forward bases. The OV-10 can perform short takeoffs and landings, including on aircraft carriers and large-deck amphibious assault ships without using catapults or arresting wires. Further, the OV-10 was designed to take off and land on unimproved sites. Repairs could be made with ordinary tools. No ground equipment was required to start the engines. If necessary, the engines could operate on high-octane automobile fuel with only a slight loss of power.

  The aircraft had responsive handling and could fly for 5 1/2 hours with external fuel tanks. The cockpit had extremely good visibility for a tandem pilot and co-pilot, provided by a wrap-around “greenhouse” that was wider than the fuselage. North American Rockwell custom ejection seats were standard, with many successful ejections during service. With the second seat removed, it can carry 3,200 pounds (1,500 kg) of cargo, five paratroopers, or two litter patients and an attendant.

  The OV-10 served in the U.S. Air Force, U.S. Marine Corps, and U.S. Navy, as well as in the service of a number of other countries. In total, 81 OV-10 Broncos were ultimately lost to all causes during the course of the Vietnam War, with the Air Force losing 64, the Navy 7, and the Marines 10. The first combat USAF OV-10As arrived in Vietnam on 31 July 1968 as part of “Operation Combat Bronco”, an operational testing and evaluation of the aircraft. The test roles included the full range of missions then assigned to FAC aircraft, including day- and night-strike direction, gunship direction, bomb damage assessment, visual reconnaissance, aerial artillery direction, and as escorts for aircraft engaged in Operation Ranch Hand.

  At least 157 OV-10As were delivered to the USAF before production ended in April 1969. In the late 1980s, the USAF started to replace their OV-10s with OA-37B and OA-10A aircraft. Unlike the Marine Corps, the USAF did not deploy the Bronco to the Middle East in response to the Iraqi invasion of Kuwait, as it believed that the OV-10 was too vulnerable.

  The USAF retired the OV-10 on 1 September 1991. In 2012, $20 million was allocated to activate an experimental unit of two OV-10s, acquired from NASA and the State Department. Starting in May 2015, these aircraft were deployed to support Operation Inherent Resolve flying combat missions over Iraq and Syria, flying more than 120 combat sorties over 82 days. They reportedly provided close air support for Special Forces missions. The experiment ended satisfactorily, but an Air Force spokesman stated they are unlikely to invest in reactivating the OV-10 on a regular basis because of the overhead cost of operating an additional aircraft type.

• Actual OV-10 Bronco Specifications:
• Crew: Two
• Capacity: cargo compartment for personnel (no seats) or 3,200 lb (1,451 kg) of freight
• Length: 44 ft 0 in (13.41 m)
• Wingspan: 40 ft 0 in (12.19 m)
• Height: 15 ft 2 in (4.62 m)
• Wing area: 291.0 sq ft (27.03 m2)
• Airfoil: NACA 64A315[124]
• Empty weight: 6,893 lb (3,127 kg)
• Gross weight: 9,908 lb (4,494 kg)
• Max takeoff weight: 14,444 lb (6,552 kg) (overload)
• Powerplant: 2 × Garrett T76-G-420/421 turboprop engines, 1,040 shp (780 kW) each equivalent
• Propellers: 3-bladed Hamilton Standard, 8 ft 6 in (2.59 m) diameter constant-speed fully feathering propellers
• Maximum speed: 250 kn (290 mph, 460 km/h) at sea level
• Combat range: 198 nmi (228 mi, 367 km)
• Ferry range: 1,200 nmi (1,400 mi, 2,200 km) with auxiliary fuel
• Service ceiling: 30,000 ft (9,100 m)
• Rate of climb: 3,020 ft/min (15.3 m/s)
• Guns: 1 × 20 mm (0.79 in) M197 electric cannon (YOV-10D) or 4 × 7.62×51 mm M60C machine guns (OV-10D/D+)
• Hardpoints: 5 fuselage and 2 underwing
• Rockets: 7- or 19-tube launchers for 2.75 in (70 mm) FFARs/WAFARs or 2- or 4-tube launchers for 5 in (127 mm) FFARs or WAFARs
• Bombs: up to 500 lb (227 kg)
• Missiles: AIM-9 Sidewinder on wings only

  Alright, lets see about building an RC model of the OV-10 Bronco. If you are like me and enjoy scratch building using balsa and plywood, then there are several plans available which you can download for free. A good simple basic build plan for someone just starting out in scratch building can be found on the Outerzone OV-10 Bronco (oz10941) webpage. This plan and resulting RC model are shown in the images below.

Images Source: Outerzone OV-10 Bronco (oz10941) webpage.

  This model is a straightforward simple design of a 42″ wingspan, twin Speed 400 size motors electric powered OV-10 RC model. The flat bottom airfoil wing can be built directly over the plans on your workbench with no special jigs required. The centerline fuselage and twin tailbooms are a “basic box” construction using formers and sides made from balsa and ply. There are CAD DXF files provided for the builders that may want to have a laser cutting firm make up a short kit for you. The DXF files also provide you a great route if you want to scale the model to the size you want.

  Looking for something larger and powered by nitro engines? Then take a look at the Outerzone OV-10A Bronco (oz8399) webpage. This is a 72″ wingspan, twin .60 sized nitro engine powered OV-10 RC model. This plan and resulting RC model are shown in the images below.

Images Source: Outerzone OV-10 Bronco (oz10941) webpage.

  This OV-10 model was designed by Frank Capan and featured in the September 1968 edition of Model Airplane News. Please note - this model is for an experienced builder. While not a simple build, it will produce a nice looking RC plane, and you can not beat the sounds you get from a twin nitro powered model flying.

  Lets take a look at another method of build for this RC model. How about a 6mm Depron OV-10 Bronco scratch build? If interested there is an excellent build log you must see on the RCGroups website. This build log has PDF plan files and lots of built images, like those shown below, to help you with your build. This model has a 44.5″ wingspan, powered by twin NTM Prop Drive Series 35-30 1100kv/380w motors turning 8x6 Master Airscrew CW+CCW 3-blade props.

  A quote from the model designer/builder “It is a joy to fly and is very docile in the air. It handles a bit of wind easily and best of all looks fantastic in the air. I went with no landing gear or flaps for simplicity but you could add them easily. The build itself is simple although shaping the canopy and nose to achieve a scale look is a bit of a challenge. Power-wise it is fine for my taste but you could put a larger prop/motor combo and get a faster plane.”

Images Source: Depron OV-10 Bronco Build Log.

  And last, but not least, is a 3D printed OV-10 RC model. If you are a 3D modeler that has built several 3D printed RC model planes, than you might want to take a look at what is available at Planeprint OV-10 Webpage.

Images Source: Planeprint OV-10 Webpage.

  This is a fully 3D printable twin-engine OV-10 RC model aircraft designed and developed by René Marschall. It has a wingspan of 1,400mm (55.1 inches); flight weight of 2,850 grams; requires a 9 channel receiver, is powered by twin electric motors such as PLANET-HOBBY JOKER 3542-6,5 V3 800 KV BRUSHLESS turning 10x7 Master Airscrew 3-blade props, has landing flaps, and retractable landing gear. The model will require LW-PLA 1100g, PLA 400g, and TPU 100g filaments. From their website you can download their free OV-10 PRINTING & ASSEMBLING MANUAL, where you can see exactly what to expect before you decide to buy the STL data.

  The flight characteristics of the Planeprint OV-10 are very pleasant thanks to the large wing area and the four landing flaps, and the big wheels are good for use on grass runways. The retractable landing gear and the unusual double fuselage design make it look fantastic on the ground and in the air.

  I hope you have enjoyed this months selection, and just maybe, I have spurred some interest in trying your hand at building an RC model airplane.

Until next month - Keep the Balsa Dust Flying and the 3D Printer Humming!!!

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Build of the Month Series - February 2026 Edition

  I hope you enjoyed last months BOTM Edition on the Royal Wing. If you have an RC model that you would like to see featured in this section or feel others may find interesting, please let me know and I will make every attempt to find scratch build plans, images, and maybe even a published build article, which I will then post in a future edition. Just send me an email @: Build of the Month.

  Ok, now lets see what I have for the month of February 2026. Getting back to the basics of building a balsa RC model airplane, not everyone will want to try a scratch build. Another option is to try your hand at a laser-cut kit. This option still allows you to build an RC model that will be unique (unlike a cookie-cutter ARF), but not having to go through all the time and effort of cutting out each individual part as required in a scratch build. Given this requirement, this month features the Sky Ranger 40, a sport RC model airplane kit designed, manufactured, and sold by Old School Model Works (OSMW).

Images Source: OSMW.

  Everyone knows that the RC model airplane market is dominated by ARFs. It is easy for those of us who enjoy building with balsa and plywood 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 GREAT company in the kit market is Old School Model Works (OSMW). Introduced in May 2018, their Sky Ranger 40 is an all-around low-wing open-cockpit sport RC model airplane based off a 1970's classic. Whether you like gentle cruising, or prefer to tear up the sky, the Sky Ranger 40's wide flight envelope makes it a blast to fly!

  The Sky Ranger 40 is as much fun to build as it is to fly. Using updated design techniques and laser-cut precision, OSMWs designed this kit so most any modeler can successfully assemble it in a short amount of time. The laser cut kit uses OMSW “WEB-LOCK Construction” - There's nothing else like it. You will build the wings straight and true with a minimum amount of fuss. 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. Included in each OSMW kit is a premium hardware package. They only source their hardware from brand name, USA manufacturers (DuBro, Sonic-Tronics, and others) to guarantee the best quality. The rugged 3/16″ pre-bent main landing gear and wheel collars are included. The 3/16″ diameter wire can absorb quite a bit of abuse for those no-so-good landings. The front hatch is held in place with magnets, which gives you easy access to batteries or fuel. A clear, pre-formed plastic windscreen is also included. The Sky Ranger 40's assembly is guided by a printed construction manual and two sheets of rolled full-size plans. What's more, you can cover and finish your Sky Ranger 40 like you want, rather than being stuck with a “me-too” offering that looks exactly the same as the others at your local field.

• Sky Ranger 40 RC Model Specifications:
• Aircraft Type: Sport Flyer
• Wingspan: 60″
• Wing chord: 10″
• Wing Area: 527 in²
• Wing Location: Low Wing
• Airfoil: Symmetrical
• Wing Platform: Constant Chord
• Airframe Length: 42.8″
• Overall Height: 17.3″
• Horizontal Stabilizer Span: 24″
• Horizontal Stabilizer Chord: 6.3″
• Flight Performance Category: General Sport
• Center of Gravity Location: 2.8″ back from wing leading edge
• Flying Weight: 3.5 - 4.5 lbs. (depending on power system selected)
• Wing Loading: Approx. 17.5 oz/ft²
• No. of Channels: 4 - Aileron, Elevator, Rudder, and Throttle
• Recommended Control Throws: Aileron 1/2″ up/down; Elevator 1/2″ up/down; Rudder 3/4″ left/right

• Additional parts needed to complete and fly the kit:
• Glow Fuel Engines: .40-.45 2-stroke engine or similar, 6 ounce tank, fuel tubing
• Electric Powered: Output of 800 Watts, 80 amp ESC, 4-5S 45C LiPo
• Engine/Motor mount and mounting hardware
• Receiver - 4 channel minimum
• Servos: 4 each 40-70 in./oz. servos (Standard servos - similar to HS-311); 1 additional servo for throttle, if using a glow engine
• Rec. Props: Use the recommended propeller for the selected power system
• “Y” servo harness
• Pushrods (two 5″ for ailerons, two 24″ for elevator & rudder, one 12″ for throttle if glow powered)
• Clevises for the pushrods (8 if electric, 10 if glow)
• 3″ diameter wheels
• 1″ tailwheel
• Covering Material
• Optional pilot figure for the open cockpit

  After reading through the Sky Ranger 40 construction manual, which you can download for free from the OSMW website, I feel this model would be an excellent candidate for someone just learning how to build a model airplane kit. Additionally, you can find all kinds of help from other Sky Ranger 40 builders on the web. Take some time and view an OUTSTANDING 20 part video build series by "Dan in VA" Sky Ranger 40 Build where he provides detailed instructions on his build of an electric powered Sky Ranger 40.

  There also are two GREAT videos from MBMrc on his Sky Ranger 40 Post-build review, and his Sky Ranger 40 Flight Video.

  The following is a quote by Terry Dunn in his review of the Sky Ranger 40 published in the October 2018 issue of Model Aviation.

  “Flying the Sky Ranger 40: The models 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.

  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.”

  I hope you have enjoyed this months selection, and just maybe, I have spurred some interest in trying your hand at building an RC model airplane.

Until next month - Keep the Balsa Dust Flying!!!

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Build of the Month Series - January 2026 Edition

  Happy New Year and I hope you enjoyed last months BOTM Edition on the Westland P12 Wendover. If you have an RC model that you would like to see featured in this section or feel others may find interesting, please let me know and I will make every attempt to find scratch build plans, images, and maybe even a published build article, which I will then post in a future edition. Just send me an email @: Build of the Month.

  Ok, now lets see what I have for the month of January 2026. During my end-of-year review of my website pages, I noticed that I did not have a BOTM Edition for what could be called a flying wing RC model. Therefore, how about something that can be called a “flying wing” and is similar in design and construction to that used for the AMTN Beechcraft Starship kit I built. Given these requirements, this month features the Royal Wing, a RC model flying wing designed by Azher from Royal Air Frames, and can be found @ Royalairframes.com, and @: Cults 3D.

Images Source: Royalairframes.com.

  I was doing a web search for 3-view drawings of a Blended Wing Body (BWB) design similar to that of the JetZero tanker/transport and just happened to come across a 3D model on Cults 3D from a designer listed as “RoyalAirframes.” I decided to take a look at other designs this company had done and eventually found their company website that has some very interesting and unusual balsa model airplane designs. This is how I found the Royal Wing featured this BOTM Edition.

  Just a few words about the company. Royal Air Frames specializes in providing high-quality, precision-engineered scale short kit designs, DXF files, and aircraft CAD designs. Perfect for aeromodeling enthusiasts, hobbyists, and DIY builders, their extensive collection includes RC airplane plans for scale models, warbirds, giant-scale aircraft, and more. Whether you are looking to create custom airframes for laser cutting or CNC machining, their laser-ready DXF plans are designed for accuracy and ease of use. Download the files and unlock endless possibilities for wooden aircraft models, foam planes, and balsa wood designs. Need something unique? They offer custom design services to bring your creative ideas to life, tailored to your exact needs. From beginner to advanced builders, their comprehensive resources make it easy to turn your RC aircraft project into a reality. Need Old Plans converted to Laser-Cutting Data? If you have vintage or hand-drawn aircraft plans, Royal Air Frames can convert them into high-precision DXF files for laser cutting or CNC machining. Their team is experienced in transforming old designs into modern digital formats, preserving the details and accuracy of the original plans while making them suitable for current manufacturing methods.

  Alright, enough with the free advertising, and lets get back to the Royal Wing model. As quoted from their website: “The Royal Wing is built for modelers who value the heritage of aeromodeling and the satisfaction of flying a well-crafted aircraft. With its 1430mm (56.3″) wingspan, this design delivers light wing loading, stable handling, smooth performance, and flight times of up to 1 hour, making every flight a rewarding experience. Constructed entirely from 3mm Lite plywood, the Royal Wing achieves the ideal balance of lightweight structure and durability. Whether you enjoy sport flying, First Person View (FPV), or simply the joy of building, this airframe offers the timeless experience of model aviation with the reliability of modern design.”

• Royal Wing RC Model Specifications:
• Aircraft Type: Flying Wing/Sport Flyer
• Wingspan: 1430mm / 56.3″
• Wing chord: Varies from 590mm down to 260mm
• Overall Length: 714mm / 28.1″
• Height: 130mm / 5.1″
• Wing Area: 54.64 decimeters² / 847 in² / 5.88 ft²
• Wing Sweep: 30.7 degrees
• Wing Loading: Approx. 11.7 oz/ft²
• Flight Performance Category: General Sport
• Center of Gravity Location: 450mm from wing root leading edge (with 10% static margin)
• Flying Weight: Estimate 1,950 g / 68.8 oz (depending on LiPo size used)
• No. of Channels: 3 - Elevons and throttle (2 servos + 1 ESC)
• Motor: DYS G3536 900kv motor, 1,050g push, 370 W, or any similar motor (this model works with a wide range)
• ESC: Minimum of 50A ESC 2-4S w/5v 3A BEC (depending on motor selection)
• Servos: 12g mini servos (x2)
• Rec. Props: Use the recommended propeller for the selected motor (i.e. 11x6 folding prop)
• Battery: 4S 2,600 - 10,000 mah LiPo

  As you can see from the above specs, using light weight flight components will result in gentle handling characteristics and very long flight durations. One builder of the Royal Wing provided RAF a FPV frame capture showing a flight duration of almost an hour (see below), and a Royal Wing flight video.

• The files included in the Cults 3D Royal Wing download package are:
• 3D CAD (.STEP) – complete 3D model for reference and modification
• DXF & DWG – laser-cut ready files for precise fabrication
• Assembly Layouts – straightforward building process

  I plugged the specs into an online C.G. calculator which established a 450mm behind the nose C.G. position using a 10% static margin. The equipment bay is large enough to accommodate just about any combination of LiPo batteries you would want to use.

  In Conclusion: The Royal Wing is a very nice RC model aircraft, but I do not recommend it for beginners who are just starting out in aeromodeling. While it does not look that hard to scratch build, hand cutting all the CAD parts from 3mm ply could be a frustrating challenge. But, if you already have some experience in RC model aircraft, and maybe even a laser or CNC cutter, this looks like a fun RC model aircraft to build and fly.

  I hope you have enjoyed this months selection, and just maybe, I have spurred some interest in trying your hand at building an RC model airplane.

Until next month - Keep the Balsa Dust Flying!!!

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