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by Ron Peterka

Aircraft Type Scale
Mfg. By Top Flite/Great Planes Model Dist., P.O. Box 9021 Champaign, IL 61826-9021
Mfg. Sug. Retail Price $509.98
Available From Retail Outlets
Wingspan 100.5 Inches
Wing Chord 19-1/4 Inches (Max)
Total Wing Area 1487 Sq. In.
Fuselage Length 67-3/4 Inches
Stabilizer Span 34-1/2 Inches
Total Stab Area 300 Sq. In. (Approx.)
Mfg. Rec. Engine Range 1.08-1.99 2-Stroke, 1.2-1.6 cu. in. 4-Stroke, 25-35 cc Gas
Rec. Fuel Tank Size 12-24 Oz.
Rec. No. of Channels 4 (5 w/Flaps)
Rec. Control Functions Rud., Elev., Throt., Ail., Coupled Ailerons/Rud., Flaps, Elev./Flaps Mix for Trim with Flaps "Down"

Basic Materials Used In Construction
Fuselage Balsa, Ply & Alum. Landing Gear
Wing Balsa, Ply & Alum. Joiner Tube
Tail Surfaces Balsa

Building Instructions on Plan Sheets Yes
Instruction Manual Yes (56 pages)
Construction Photos Yes

Radio Used Futaba 8 UAFS 8 ch., Hitec Servos
Engine Make & Disp. 35 cc U.S. Engines
Tank Size Used 24 Oz. Great Planes
Weight, Ready to Fly 408 Oz. (25 Lbs., 8 Oz.)
Wing Loading 39 Oz./Sq. Ft.

WE LIKED THE: Lovely CAD plans and provision for scale detailing, quality of materials, excellent die-cutting, look of the finished model, and scale flight performance.
WE DIDN'T LIKE THE: Main and rear spars wouldn't match plan's rib spacing, vacuum-formed trim parts were difficult to use.

Founded in 1927 by Eddie Stinson, the Stinson Aircraft Co. soon merged with the E.L. Cord Automobile manufacturer. After the 1929 stock market crash, the company merged again with the Convair Corporation. Throughout its years of operation, Stinson's aircraft were noted for quality, roominess, and sumptuous interiors. They were not fast, but they were easy to fly and offered a comfortable ride for company executives traveling from city to city.

The 1938 model SR-9 Reliant, known also as the "Gull Wing" Reliant due to its distinctive wing shape, was no exception. It had full leather interior seating, automotive type roll-down cabin windows, and was offered with a variety of engine options. The SR-9, for instance, could be purchased with engines ranging from the 225 hp Lycoming radial engine, to the 445 hp Pratt & Whitney Wasp Jr.

Max speed was only about 145 mph with a leisurely cruise of 135 mph. Range was approximately 785 miles at cruise power settings. Equipped with flaps, the SR-9 could take off fully loaded in 650 feet of runway.

They were, and each remaining aircraft is, a classic aircraft in every sense of the word.

Top Flite offers a 1/5 scale kit intended as a sport scale model that could be built as a competitive scale model with some extra work and detailing. Traditional materials and building methods make assembly fairly straightforward, although the sheer size makes for a complex model that is definitely not a beginner's project. The model is designed for scale operation and violent maneuvers and aerobatics are not advised. If you plan to do aerobatics, or use the larger engines, then making the wing struts functional and beefing up the horizontal stabilizer is recommended as mandatory.

I was happy and surprised when the UPS truck dropped off the kit from Great Planes for this review. Happy because I love building the Golden Age aircraft that this Stinson so elegantly characterizes, and surprised at the size and weight of the kit in its 49" x 11" x 6" box. The UPS man even offered to help me carry it into the house, it was that big.

Be advised, the kit is so well packed that you will be hard-pressed to repack the parts in the same box once you have unpacked it. In this case, the kit arrived completely undamaged.

The CAD-drawn plans come printed full size on four huge sheets, and even then you need to join two sheets to get a full side and top view. A well illustrated and competently written 56 page instruction book is also supplied. You will need this book. Trust me. Read it.

A complete set of hardware, except for hinges, is supplied. Top Flite, correctly I think, expects you to use your favorite type of hinges. They do suggest the Robart hinges and Sullivan pull-pull rudder control system. I like the Robart hinges and used the large size hinge points.

A huge amount of wood is included, much of it die-cut. It is important to identify each supplied part (mark them clearly) so you can find each part as needed and avoid wasting material. I spent two hours checking and marking, and I still cut up a couple of the wrong pieces. Die-cutting was excellent throughout. Vacuum-formed plastic parts make up the wheel pants, engine cowl, and various trim items like window frames and strut fairings.

A 1.08 to 1.99 cu. in. 2-stroke is recommended, or 1.2 to 1.6 cu. in. 4-stroke. A 25 cc to 35 cc gasoline engine can also be used. I chose the U.S. Engines 35 cc engine because I planned to "dress up" the model and fully expected it to weigh close to 25 pounds when finished.


Following the instruction manual closely, I began with the tail surfaces. You will need to pre-assemble many parts throughout construction and you start with laminating the die-cut horizontal stabilizer spar. I can recommend the Great Planes Pro CA glues, as well as the Great Planes epoxies. I also used some aliphatic resin (Titebond) as well.

The horizontal stabilizer and vertical fin are each built on the building board and tabs hold the symmetrical ribs off the board in good alignment. Once capstrips and top center section sheeting are in place, the fin is lifted off the board for completion.

The rudder and elevators are built vertically on the respective built-up leading edges. A center core provides great stiffness, and riblets added on each side along with capstrips provide a scale "built-up" appearance when covered. Again - follow the instructions.

The wings come next, they are complex and the instruction book offers numerous tips to get a true and strong wing assembly. I found it critical to read ahead and think out each series of sub-assemblies. The construction must be done in a prescribed order in some places.

The wings gave me the one most disturbing problem in the kit. I found that the die-cut main wing spars did not quite match the plan's rib layout and spacing. After several tries, I wound up installing the ribs to match the die-cut spars rather than cut new spars. This would not be much of a problem with a sport scale model, but could be a serious problem if you plan on a more exact scale model.

The wings are mounted to the fuselage with a large diameter aluminum tube in cardboard tubes heavily reinforced in each wing root. Allen head screws installed through the operating cabin doors hold the wings to the fuselage. Struts are screwed in place after the wings are mounted. I chose high-torque Hitec 605 ball bearing servos for both ailerons and flaps.

I covered the wings with Super Coverite after installing wiring and bulb sets for RAM scale running lights. I also built the wings with operating flaps and an operating retracting landing light in the bottom of the left wing. The landing light is keyed to the flaps and comes down and "on" when the flaps are deployed.

Fuselage construction starts with assembling a set of complex former tops and bottoms. When you finally get all the formers built, you can build the aft bottom portion of the fuselage upside down over the plan top view. A large number of temporary 1/4" sq. balsa braces are installed to hold the assembly square during final assembly. After the former tops are added on, a preassembled forward fuselage assembly/engine mount is installed. The laminated plywood side pieces of this mount require substantial force to bend them into place, so be careful here.


I used a Great Planes vibration absorbing engine mount and a U.S. Engines 35 cc engine which fit perfectly, but smaller engines may need a mount box spacer to set the prop in the correct position to clear the cowl. The U.S. Engines muffler keeps the sound down and fits well within the cowl.

The horizontal stab and vertical fin are installed after carefully leveling the fuselage on the workbench. The wing mounting tube assembly is then epoxied in place and ply landing gear mount plates prepared for mounting the heavy bent aluminum gear. Sheeting the front section is next on the list. You will cut the door openings later and build scale cabin doors for access to the wing retaining screws used to assemble the wings to the fuselage for flight.

I chose to install the eight channel Futaba 8UFAS radio gear, including one rudder and two elevator servos, dual battery packs, and dual charge port/switches in the scale baggage compartment accessible through a scale door. This allowed a fully detailed passenger compartment and helped balance the model. The interior, as well as the exterior details were taken from photos supplied by Bob Banka. A pair of 1400 mAh battery packs from Cermark Electronics, along with a pair of their combined switch/charging jacks, took care of radio power with a measure of redundancy. Heavy 22 gauge extensions, also from Cermark, provided contact with all nine servos with little voltage loss on the long runs. All wiring was kept well away from the engine magneto and kill switch. With a model of this size, cost, and complexity, safety has to be planned from the start of construction. A 24 oz. Great Planes fuel tank was installed.

The real aircraft could have had two baggage doors, one on each side, for easy access to the owner's golf clubs. I built just one that serves as switch and radio access. While I was at it, I designed and built internal, spring loaded door latches. A twist of the external door handle gets you into each cabin door as well as the baggage door.

With almost 1500 square inches of wing area, you can carry almost anything you want in the way of scale detail and still have a decent flying model. A scale set of upholstered seats carved from foam and covered with a single layer of fiberglass and epoxy seemed right, along with a walnut-veneered instrument panel. A complete set of seats weighs just a couple of ounces and, when painted with acrylic paint, looks very realistic. The kit comes with an excellent laser-cut ply instrument panel and decal instruments. I paneled the interior of the passenger compartment with 1/64" plywood. A vacuum-formed plastic kit is available from Top Flite if you want a somewhat simpler interior with fewer hours of construction.

Plastic vacuum-molded parts are supplied to build up the wheel pants and classic "bump" cowl a well as a number of other useful fairings. The cowl is assembled from a front and rear section reinforced with laminated ply parts. When that basic cowl is together, you can add the 18 formed rocker box "bumps" and fair them in with epoxy filler or F&M Stits Feather Coat filler. The Feather Coat mixes like epoxy and, when cured, sands to an all but invisible feather edge. A fair amount of work, but a surprisingly strong cowl when completed. Top Flite also has a nice lightweight dummy engine that was installed to hide the U.S. 35 engine.


Again, the large size allows a scale covering and finish for maximum "wow" effect. Here I prefer the F&M Enterprises Stits process used over Super Coverite fabric covering. The Super Coverite irons-on easily and shrinks beautifully. F&M offers 1/2" wide pinked tape that, when pulled across a hot (350°F) iron, shrinks to about 0.4" width which is perfect for a 1/5 scale reinforcing tape. The tape is not coated with adhesive and should be glued on with Stits cement.

At least two coats of Stits Poly-brush provides a bonding finish and filler to the Super Coverite and a few more coats of silver Poly-spray should give you a good base for the final color coat of Poly-tone. Choose a color scheme from a real Gull Wing at your local airport, or contact Bob Banka for a Foto Pak. He has several to choose from with different color schemes. The prototype model shown on the kit box is patterned after a real Stinson restoration.


The engine was fitted with a Top Flite 18 x 12 prop and a couple of tanks of fuel run through as the engine and radio systems were checked for possible interference and surfaces adjusted.

Test flights were flown at a local private airport that allows a larger area for safety by Curtis Kitteringham, a fellow Palomar R/C Flyer club member and a much better pilot than I.

The first flight lifted off smoothly after a nice scale take-off roll. At altitude, some right aileron trim was dialed in and Curtis began to maneuver. It became obvious that the plane was sensitive in pitch, and any turns required rudder input for a coordinated turn. A few passes for in-flight pictures and a smooth landing. The model floats much farther on landing than expected for a heavily loaded craft.

After extending the elevator control horns to the maximum, adjusting the idle rpm, and installing the wing struts, the second flight was much more manageable. With still nervous hands, I was able to get in some stick time and put in some figure eights around the field. With some altitude, the flaps were tried and we discovered that considerable down elevator was needed with about 30° of flaps, but the sink rate was much better for landing. They will be useful when flying in smaller fields.

At this time, plans are to add some weight in the nose to reduce the pitch sensitivity further and to switch to an 18 x 10 prop to lower the thrust at idle rpm. All in all, the model flies very much as I would expect the original Stinson to have flown, and I am looking forward to many scale-like flights. The U.S. Engines 35 cc engine has been trouble-free and very economical to operate.

It seems that so many flight review aircraft "fly right off the board" with no trim needed to speak of. My planes never seem to be that lucky. For me, I expect to adjust the model over several flights and eventually have a fine flying model that is a pleasure to fly. This wonderful Golden Age model is typical of my experience.

Suppliers Mentioned In Review:
RAM, Inc.
229 Rollins Rd., Round Lake Beach, IL 60073
Great Planes Model Dist.
P.O. Box 9021, Champaign, IL 61826
Bob Banka, Scale Model Research
3114 Yukon Ave., Costa Mesa, CA 92626
Cermark Co., Inc.
107 Edward Ave., Fullerton, CA 92833
F&M Stits Products
22522 Auburn Dale Dr., El Toro, CA 92630
Hitec RCD Inc.
12115 Paine St., Poway, CA 92064

Photos by Ron Peterka. Reprinted with permission.
December, 2000 R/C Modeler Magazine
Editor: Dick Kidd

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