TOP FLITE DOUGLAS DC-3
by Ron Baddford
Name DOUGLAS DC-3
Aircraft Type Twin Engine - Sport Scale
Mfg. By Top Flite, 2904 Research Road, Champaign, Illinois 61826-9021
Mfg. Sug. Retail Price $349.99
Available From Retail Outlets
Wingspan 82-1/2 Inches
Wing Chord 9 Inches (Avg.)
Total Wing Area 750 Sq. In.
Fuselage Length 55-1/2 Inches
Stabilizer Span 25 Inches
Total Stab Area 200 Sq. In. (Includes Elevator), Stab = 130 in², Elev = 70 in²
Mfg. Rec. Engine Range .25-.40 2-Stroke
Rec. Fuel Tank Size 10 Oz.
Rec. No. of Channels 6
Rec. Control Functions Rud., Elev., Throt., Ail., Flaps & Retracts
Basic Materials Used In Construction
Fuselage Balsa & Ply
Wing Balsa & Ply
Tail Surfaces Balsa
Building Instructions on Plan Sheets No
Instruction Manual Yes (68 pages)
Construction Photos Yes
Radio Used Futaba 6XA
Engine Make & Disp. O.S. 40 LA (2)
Tank Size Used Great Planes 10 Oz. (2)
Weight, Ready to Fly 157 Oz. (9 Lbs., 13 Oz.)
Wing Loading 30.19 Oz./Sq. Ft.
WE LIKED THE:
Kit engineering, quality materials, excellent die-cutting, well laid out plans, good matching between parts and plans, engine mounts included, and instruction manual.
WE DIDN'T LIKE THE:
Minor descrepancies between photos and production model, assembly instruction book and plans identify same part differently, and a few drawing errors.
There is not much that anyone can say or write about the Douglas DC-3 which has not been previously covered by someone somewhere. The DC-3 is a one-of-a-kind classic that will go down in aeronautical annals as one of the most famous and popular aircraft of all time. For an aircraft to be designed and built in 1937 and still be operating today, says that Donald Douglas and his team of designers certainly did somethin' right. But, for any newcomer or young'n who just happens to be reading these words of wit and is not really familiar with the Gooney Bird, Majestic Lady, or Queen of the Skies, let me brief you on her by quoting some of the DC-3 historical facts found in the instruction manual: The DC-3 design came about as a result of American Airlines needing to remain competitive with TWA (who had the DC-1) and with United Airlines and their Boeing 247's; the DC-3 was the very first aircraft which could generate revenue by only carrying passengers; it usually took about five days or less to build a DC-3. Between 1935 and 1947, the Santa Monica, Long Beach, and Oklahoma City plants produced a total of 10,654 DC-3 and C-47 variants; there are approximately 1,500 DC-3's flying today, with most being recognized as collectors' items. And I believe I read somewhere that the DC-3 flew over 100 billion miles and carried over 700 million passengers from 1937 to 1998 - if this is true, WOW!
Robart/Top Flite retracts provide a very realistic option.
I have been very fortunate to have some fond memories of the DC-3, especially, finished in the Eastern Air Lines motif. In 1950, my dad - who worked almost 30 years for EAL - took me on a flight from Miami, Florida, to Vero Beach, Florida in an Eastern DC-3. It was just my dad and I and the pilot and co-pilot aboard and we dropped down low and slow over the beach for one of the most beautiful flights of my life. At one point, I remember we climbed and (if memory serves me correctly, the pilot was an Eastern test pilot, Joe Toth) I was given the opportunity to "come up front and watch." That memory has stayed with me for 49 years and it becomes more valuable each passing year! So, after all this, you can understand why I was excited when given the opportunity to do the kit review and be able to finish it off in the Eastern trim. This is also why you will see in the review, I decided to go full bore and added the scale rudder hinge line; scale ribs to the rudder, elevators, and ailerons; retracts; flaps; navigation and landing lights.
Two O.S. .40 LA engines provided the power for the DC-3.
With its advertised wingspan of 82-1/2", the Top Flite DC-3 isn't really a large model by twin standards, but it is large enough to participate in IMAA events. The only deviation from full scale is an increase in the wingtip chord, a change in the engine position and thrust lines, an increase in fin, rudder, stab, and elevator sizes, and a modification to the wing airfoil. Even with these minor design changes, the finished model should "hold its own" in any AMA sport scale or stand-off scale event. The three full-size plans call for two .25 to .40 2-stroke or two .40 4-stroke engines. Plans also show the installation of two O.S. .30 Wankels. I guess with a little work, it could also be modified to go the electric route.
Scale-type built-up control surfaces were used on the review model.
The Top Flite DC-3 kit arrived by UPS and was securely protected from any shipping "rash." The kit comes in a 6-1/4" x 11-1/2" x 49-1/2" box with a large colorful photograph of the finished model all decked out in Eastern Air Lines decor. This large photograph serves as an excellent reference if you decide to finish your DC-3 in the EAL decor. Also on the box top are lists of items needed to complete construction of the kit, recommended engines and accessories, detailed photos of various construction steps, and the completed airframe. When you open the box, the first thing you see is a heavy cardboard divider which protects the beautiful stacks of die-cut balsa part sheets, stick wood, decals, three rolled sheets of full-size plans, a beautiful 68-page illustrated instruction manual, two Great Planes adjustable engine mounts, and all of the formed wire parts and hardware your modeling mind could ever imagine underneath. On top of the cardboard divider are the beautiful vacuum-formed cowls, wing fairings, tail cone, and cockpit.
The framed up model, ready for covering.
Before starting construction, please do yourself a favor and read the incredible instruction manual. Within its 68 pages are so many tid-bits of information and construction photos, that you are doing yourself a disservice if you fail to prepare ahead. Even if you are an experienced builder, there are some spots where you can build yourself into a corner if not careful. The manual is formatted in the step-by-step/check-off box construction scenario which begins with the tail group and goes to the fuselage and, finally, to the wings. Also included in the manual are several "Hot Tips" which are extra selected construction steps or construction practices which are fully explained and contain plenty of photos and provide a definite assist to the builder.
Landing gear extended and retracted.
I found the kit to be somewhere between moderately difficult and difficult to build, and you must stay focused on the project, plan ahead, and follow the instructions to the letter. Also, plan to have your workbench and immediate area clean and clear before beginning the DC-3 project. Before starting construction, I reviewed the material list and inventoried and marked all the parts of the kit so they would be easier to locate once construction began. After marking, I sorted the parts by component.
Construction begins with the stab, elevator, fin, and rudder. Locating the correct pieces of balsa stick wood is made easier by the prelocating, marking, and sorting. Actually, the edge joining wasn't that bad since my kit contained some real true and straight 1/16" sheets which went together rather quickly, and I used the recommended Great Planes PRO Wood Glue for this. During the construction of the stab and elevator halves, the high quality of the balsa and the crispness of the die-cutting becomes obvious. Especially nice is the excellent match between the parts and the full-size drawings. During the construction of the stab, I used the Great Planes PRO Wood Glue throughout. The two elevator halves are constructed using a 3/32" balsa core with 1/16" balsa ribs to simulate the fabric covered surfaces of the full-size DC-3. The drawing shows the scale elevator rib spacing, and this is the route I took. At this point, I also added a 1/8" balsa scale trim tab located per the 3-view drawing on the rear cover of the instruction manual.
The instruction manual does advise to use caution when sheeting the second side of the stab to avoid warping. The hinge slots for the stab and elevator halves were marked per the instructions and were "cut" using the new Great Planes "Slot Machine." The use of this new little "tool" certainly speeds up the hinging process, plus making it much easier at the same time. Before constructing the fin and rudder, a choice must be made between building a sport-type rudder with a straight hinge line or the scale staggered hinge line of the full-scale DC-3. I chose the scale rudder - this does take much more time and much more work, but the results are well worth it. The fin is constructed exactly like the stab, the only difference being the method of hinging for the scale hinge line. The rudder also uses the core and rib construction. Again, the scale rib spacing and additional trim tab detail was chosen. One thing I did on the rudder which was not on the plans or in the Instruction Book was to add some scrap 1/8" balsa between the 3/32" balsa core and the 1/16" balsa leading edge sheeting to strengthen the 1/16" leading edge sheeting. By constructing the tail group (or empennage for you purists) first, you get into a building rhythm and of reading ahead in the manual, preparing your steps, and building carefully. You also need to build the tail group first since its incorporated into the construction of the fuselage.
Construction of the fuselage begins with a horizontal crutch out of 3/16" x 3/8" balsa strips to which are added the top half plywood and balsa formers. The crutch is a machined channel shape. After the crutch is pinned in place and the lite ply top former halves are glued to it, a piece of 3/32" x 3/16" balsa is inserted into the channel and provides a base for the top half planking. I found this method to actually make the step of planking at the horizontal joint a bit easier since it does provide a nice solid base from which to glue and secure the 3/32" x 1-1/2" horizontal joint planking. The stab and fin are built into the top half. Care must be taken to ensure that the stab has the +1degrees incidence built in during the construction. Also critical during the fuselage top half construction is the alignment of the stab and the vertical fin. The fuselage is sheeted from the patterns shown on the full-size plans. One important note here is to trace the stab/fin filler pattern onto some 3/32" balsa before building the stab onto the crutch. If you don't, the stab hides the pattern! The planking proceeded without too much effort. After the top planking is completed, but before any sanding, it is advisable to fill the seams and joints with some lightweight balsa filler.
With the top planking complete, the entire fuselage assembly is removed from the workbench and placed upside down in a stand. Here, I used a Robart Super Stand per the instruction manual. The bottom half formers, wing saddles, and tail wheel assembly are installed (the tail wheel assembly looked a little "fragile" so I braced it with some scrap 1/8" lite ply and 3/16" balsa). This is followed by the rudder and elevator pushrod assemblies, and the rudder and elevator servos (I used Futaba S3003s) mounted as shown in the instruction manual. Nothing really out of the ordinary, just follow the instructions and photos. The ABS plastic cabin top was cut out with a pair of Hobbico Diagonal Cutters, then fitted and glued in place. This was followed by the gluing in place of the balsa nose block. The nose block was then sanded to shape and smoothed into the contour of the cabin top and the fuselage planking with an 11" Easy-Touch Bar Sander and 80 grit sandpaper. I also used some medium, fine, and superfine 3M Sanding Sponges for sanding the fuselage. These are excellent little sanding tools which can be folded to just about any shape you need and they're available in most of the building supply outlets.
The addition of the dorsal fin just about completed the fuselage. I did opt for the removable hatch at the bottom rear of the fuselage which allows for access to the rudder and elevator clevises. I also drilled a 1/4" diameter hole in F11 to allow for the passage of the RAM (#15) white navigation tail light and its wiring. The last thing to do to complete the fuselage is to install the ABS tail cone. I cut out the end of the tail cone to allow for the installation of the RAM white navigation tail light. I also used a Radio Shack #272-340 White Lense which fits perfectly into the end of the tail cone and adds a great deal of realism to the installation.
Construction of the wing is next. However, before beginning construction, the choice of retracts or fixed gear must be made since different illustrated steps of the instruction manual apply to one or the other. I went with the Robart/Top Flite retractable gear which is available as an option. This is a very realistic replica of the original DC-3 gear and is quite easy to install. The first step in the wing construction is the fabrication of the firewalls. Remember to make one left and one right. The firewall doublers were found in the plastic bag with other hardwood pieces and were not die-cut as per the instruction manual. Initial construction of the ribs, spars, leading edge and trailing edge spars was done on a G.P. Magic Magnet Building Board System. This system really proved to work out well and kept the ribs and spars in perfect alignment throughout construction, while allowing any repositioning where necessary.
Before placement of the ribs into position, I drilled 3/8" diameter holes in each rib for the running of the RAM (#15) red and green wingtip navigation lights and the two (#16) landing lights which I located between ribs W5 and W6 on each wing panel. The firewalls are temporarily installed and the correct engine thrust line is established. After the retractable gear is installed, the air tank and valve is installed. The gear is then removed and the 3/32" balsa center section and 1/16" balsa left and right wing panel bottom sheeting is installed. The flaps came next and were not difficult but were time-consuming. The instructions show a neat way of joining the center section and the wing panel flaps utilizing a "tube and wire joiner." To control the retracts and throttles, I used Hobbico's new CS-15 sub-micro servos. The small size of these sub-micro servos really helps toward getting all "that stuff" into the wing center section. For the ailerons and flaps, I used Futaba S3003 servos with servo extensions for the aileron servos and a "Y" connector for the throttle and flap servos.
Next came the fuel line routing and the routing of the retract air lines. Then, last but not least, came locating the fuel tanks, batteries, and micro-switch for the RAM lighting systems. With the equipment installation complete, the 3/32" balsa top sheeting is installed. After top sheeting of the wing is finished, the ailerons are constructed. Here again, I used the scale rib spacing so assembly took a little longer. The ailerons are engineered the same as the elevators, using a sheet balsa core with ribs. Next came the reinstallation of the landing gear and the construction of the nacelles. Engine mounting and ABS cowl fitting finished up the wing construction. The instruction manual has excellent photos to guide you through all the steps. Final assembly steps include fitting the wing to the fuselage and installing the monstrous ABS wing fillets. Top Flite sure came to the rescue by making these fillets out of ABS, because if they were built-up, I think I would still be on them. After fitting the wing to the fuselage, the model is laterally balanced.
Prior to covering, the whole airframe was sanded with 150 grit and 220 grit Adhesive Backed Sandpaper on the Great Planes Easy Touch Bar Sanders, along with medium, fine, and superfine 3M Sanding Sponges. Take your time here, patience pays off in a big way. Fill all of the final little dings and seams with filler, then finish up with 400 grit sandpaper and a Tack Rag. All of the ABS plastic assemblies were primed with a coat of Top Flite White LustreKote spray paint. By now, the choice of a covering(s) and decor should have been made. I chose the Aluminum MonoKote route with the Eastern Air Lines decor, although the DC-3 would also look sharp finished off in a military olive drab and/or camouflage decor. To prepare the surface for covering, I used some Coverite Balsarite and a Top Flite Woodpecker Perforating Tool. The covering was applied using both a Heat Sealing Iron and a Heat Gun. LustreKote Aluminum and Insignia Blue spray paint was used for "touching up" where needed.
For the scale trim panel lines, I used a T.F. Stripe Machine along with MonoKote trim sheets, which eliminated buying batches of 1/32" and 1/16" and 1/8" wide stripe tape which would have roughly equated to a monthly mortgage payment. The last page of the instruction manual has a great 2-view drawing which depicts all the panel lines of the full-size DC-3 and was used as my reference for the panel lines of the model.
The radio used was the Futaba 6XA with an FP-R127DF receiver and a 1,700 mAh battery pack. Futaba S3003 servos were used on rudder, elevator, ailerons (2), and flaps (2). Hobbico Command CS-15 sub-micro servos were used for the throttles (2) and retract air valve.
The engines used were 2-stroke O.S. 40 LA's. I chose to break both of them in at the same time using Top Flite 11 x 5 wooden props on 5% nitro. I ran almost a gallon of fuel through both engines before mounting them in the model. For flying, I used two Master Airscrew 10 x 7 three-bladed props. The engines were mounted on the Adjustable Engine Mounts which are supplied with the kit.
There are six pages of information dedicated to "Get Your Model Ready to Fly" in the instruction manual. It covers verifying the engine thrust line angles, final balancing, recommended control surface throws (for both low-rate and high-rate settings), engine synchronizing, a very thorough check list and, finally, flying. The check list is 22 steps and should be copied and taped to every flier's field kit. The flying instructions take you through engine out procedures and take-offs and landings. I balanced the DC-3 and set up the control throws as per the instructions.
Since it had been quite some time since I had flown a twin, I was a bit hesitant about the possibility of putting the DC-3 through some unnecessary punishment, especially since it is such a beautiful model when finished. However, all my worries disappeared as the DC-3 turned out to be a beautiful flying twin.
The first part of my first flying session was spent doing some ground taxiing to get used to the handling and doing some engine checks with a tach to synchronize the engines rpm's - especially at full throttle (I got mine to within a tad over 200 rpm of each other). After the engines were synch'd and ground handling was "mastered," there was nothing left to do but advance the throttles and "give it a go." I eased the throttles forward and, in a matter of about twenty to thirty feet, the tail was up and a little up elevator had the DC-3 lifting up real gently, although a little on the fast side. I climbed out to a safe altitude, made a turn, and set the trim for straight and level flight. I brought the DC-3 past me and my two sons (mechanic/pilot and photographer) and it was one of the prettiest sights I have witnessed since I have been modeling. Make no doubt about it, the DC-3 finished off in the Aluminum Eastern Air Lines decor is a very pretty model.
Another turn and, as she flew by us, I hit the retracts and we watched as they came up as smooth as silk. I made some more turns and came in a bit lower on my passes for the article pictures. I climbed again and slowly reduced the throttle - I noticed then that I never was at full throttle - and entered into a stall. This is where I started to become a little nervous, fearing a possible engine or engines out, but everything went according to Hoyle and she just slowed up and continued her nose up attitude - then - she dropped with her right wing a tad ahead of the left. Recovery was no problem with the engines purring as the throttle was advanced. She performed real well at slow speed before the stall which made me comfortable about the eventual landing. Then a climb back up and the flaps were given a try. With low throttle and full-flaps, she almost stops and parks. With about half throttle and no flaps, I set up for the first landing. I opted for a not-so-long slow approach and quickly found out I was still coming in hot. I did a go around and set up for a longer approach and, reducing the throttles to idle, she set down with only minor bouncing and rolled to a stop. Man, was I happy and relieved. And Proud.
The next flights resulted in experimenting with the flap and throttle settings for landings. With flaps, you get a real scale plus with the RAM landing lights operating directly off one of the flap servos when coming in with the flaps lowered. Nice Touch! For my last flight, I wound up with flaps near 45 degrees and her nose pointed at the point of touchdown with just enough throttle to keep her airborne - flaring out and reducing throttle to idle right before touchdown. That had me sweating. But, it was my last flight for the day and the DC-3 looked beautiful landing this way. I never did witness an engine out nor did I try to assimilate one. All initial flights were made with the engine cowls removed.
The Top Flite DC-3 is truly one of the premiere kits on the market today. It offers excellent kit engineering with quality materials and comes with well-detailed plans and a well-written and illustrated instruction manual. The supplied ABS plastic cockpit, wing fillets, cowls, and tail cone are certainly one of the benefits of the kit since they save so much difficult and time-consuming work. The DC-3 is definitely not a beginner's model and even experienced modelers must follow the instruction manual and plan ahead. The model does take a lot of time to build and, with its size, it takes up a lot of shop space. I definitely recommend using twin 40's as a choice of engines just to stay on the "safe" side if an engine out should occur. Also, a complete break-in of both engines before flying is mandatory. The two O.S. 40 LA's that I used performed extremely well and never gave me any problems or surprises. The biggest plus of the DC-3 is that it provides an excellent way to enter twin engine scale flying with a well-built beautiful model. With the success of the DC-3, I hope the guys (and gals?) at Top Flite are considering another twin or four engine design soon - how about a nice Mosquito or B-25 or B-17 or B-24 or ... ?
Photos by Ron Baddford. Reprinted with permission.
May, 2000 R/C Modeler Magazine
Editor: Dick Kidd