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This item is discontinued. GREAT PLANES GIANT AEROMASTER 
SPECIFICATIONS SUMMARY
The Aeromaster biplane has been around for many years now. It was in the late 1960's that Lou Andrews designed and kitted the original model. It proved to be very popular and the model was available for many years. Some time ago, Great Planes Model Mfg. bought the design and manufacturing rights to the Aeromaster and now produced a slightly modified design for the giant scale modeler. Ailerons have been added to the top wing, a round cowl, bolt-on wings and a plastic canopy are a few of the changes. The Giant Aeromaster comes in a huge box measuring 50" x 12" x 6". It is well packed with a lot of balsa sticks, sheets, die-cut balsa, and lite ply parts. This is a very complete kit with an extensive hardware package. The only hardware parts not supplied are the hinges. There are three rolled sheets of plans along with a 52 page instruction manual which is one of the best you will ever see. Someone at Great Planes spent a lot of time on this manual which contains the detailed building instructions, many excellent photos, building tips, covering, finishing, etc. It is very important to follow the building sequence as outlined in the manual. Construction: Wings: The wings were built next. The Aeromaster bottom wing is straight, and the top wing is swept back. There is no dihedral on either wing. Here is where you want to follow the sequence of building as outlined in the instruction manual. The top right wing is built upside-down over the left wing panel drawing. Same for the bottom wing. Follow the manual carefully and there will be no problems. The wings are not difficult to build but do take some time. With two wings and all the sheeting, capstrips, etc., there are a lot of pieces to work with. The Giant Aeromaster has ailerons in both wings. You can choose to operate the four ailerons with two servos, or use a servo on each aileron. I used two servos. Fuselage: This is a real strong fuselage. The sides are 1/4" sheet balsa. 1/8" lite ply fuselage doublers are assembled over the plans and glued to the 1/4" sheet sides. Once the sides are completed, the fuselage goes together very easily; but, like the wings, there are a lot of parts and it does take some time. Great Planes shows two different servo installations: one with the servos mounted in the fuselage under the cockpit and the other with the servos mounted in the rear and on the outside of the fuselage. If a larger engine such as a Zenoah G-62 is going to be used, then it would be best to mount the servos in the rear of the fuselage. A U.S. 41 engine is shown on the plans. If this engine or a similar one such as a Quadra 42 or Zenoah G-38 will be used, then mounting the servos in the center of the fuselage would be the better choice. The Giant Aeromaster will accept a wide variety of engines. As mentioned before, the U.S. 41 engine is shown on the plans. If using this engine or a Quadra 42, G-38 type of engine, then just follow the instructions on the plans and in the manual. A larger engine will of course require some modifications. An engine smaller than those mentioned, should not be considered.
Engine: The engine I used in the Giant Aeromaster is the U.S. 41. It is very similar (in fact, it looks exactly the same) in appearance to the Quadra 42. This engine comes equipped with a spring starter, mount, muffler, throttle hook-up, and a single bolt prop hub. It is ready to run and install in an airplane right out of the box. However, there is one item that should be installed on the engine before using it. Great Planes has an accessory available for the engine called a "Velocity Stack." This stack attaches to the carburetor and prevents fuel from siphoning out of the carburetor while the engine is running. The U.S. 41 was run in for about one hour before installing it in the model. The prop used to break it in and to fly with is an 18 x 10 Zinger. The engine was mounted onto a "Mighty Engine Test Stand" manufactured by American Hobby Products, 12 West Hill Circle, Reading, MA 01867. This company makes quite a few different size engine test stands and all are of very high quality. The "Mighty" size test stand will handle engines up to 5 cu. in. displacement. The U.S. 41 engine that I have starts very easily if you do not prime it. Priming through the intake will easily flood it. Instead (with the ignition switch off or the plug lead disconnected), choke the engine several times. Then with the ignition on, turn it over with the spring starter. It will start every time this way. The U.S. 41 is a very fine running engine and provides plenty of power for flying the Giant Aeromaster. It turns the 18 x 10 Zinger prop at 7,000 and idles at about 1,800 rpm. A fuel mix of 32-1 is being used. Radio Installation: The radio used in the Giant Aeromaster is an Airtronics Stylus with six Hitec servos. Two HS77BB servos were used for the ailerons, two HS425BB for the elevators, one HS422 for the throttle, and one HS700 for the rudder. An 1800 mAh NiCd battery pack from E.H. Yost was used for the airborne power supply and mounted just ahead of the lower wing. The required clevis and pushrods are supplied in the kit. A plastic pushrod tube was used to connect the output arm of the throttle servo to the engine throttle. Two Airtronics 36" servo extension cables were used to connect the aileron servos. An engine kill switch was mounted inside of the lower part of the cowl. Covering & Finishing: The cowling supplied with the Giant Aeromaster is molded out of ABS plastic and comes in three pieces. The wheel pants are also molded of the same material and each comes in two pieces. After much cutting and fitting, the parts were assembled with thin CA and the seams filled with Bondo Spot Putty. The seams on the inside were reinforced with fiberglass cloth. After a final sanding, both cowl and pants were sprayed with Top Flite LustreKote primer and then sprayed with LustreKote yellow. The Aeromaster airframe was covered with Top Flite yellow MonoKote. It takes a lot. Figure on using at least a 25' roll. Red trim tape was used for the trim, and the struts were painted black.
Flying: The Aeromaster was set up with the amount of control travel as called for in the instruction manual. The plans show a 3/4" C.G. range and the model was balanced at the forward part of this range. After a radio range check with engine running and some taxi tests, the Aeromaster was lined up with the runway and the throttle slowly advanced. Take-off run was a little shaky but the model lifted off easily. Only slight trim adjustments were required on the ailerons and elevator for hands-off flight. Although the model weighs over 20 pounds, the U.S. 41 engine was pulling it through the air with ease. Loops from level flight are no problem, stalls are gentle and straight ahead and axial rolls require very little rudder or elevator correction. This is one nice flying model. Landings should be made with some power. There is a lot of drag with this model and the idling U.S. 41 engine with that big prop adds to it. Use some power all the way down and cut back as soon as the wheels touch down. The only problem we had flying this is that it was hard to hold it steady on the take-off run. The rudder is very sensitive. It is best to use dual rate on the rudder to cut the travel down. Other than that, there are no problems. Conclusion: The Giant Aeromaster is an excellent quality kit, enjoyable to build, and an outstanding flier. If you like biplanes, then you'll love this one. Photos by Don Belote. Reprinted with permission.February, 2001 R/C Modeler Magazine Editor: Dick Kidd
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