How to Build Your Own Aircraft by Mary_jMenintigar


More Info
									                     Choosing Your
  A wide variety of aircraft types, styles and platforms exist;
moreover, the materials of which they are made and the level
  of fabrication “out of the box” is highly variable. The author
        offers advice that will help you make the right choice.

                    e now have a good understanding of                      you can buy an RTF model and simply fly, which is

     W              the electric power system and the
                    RC system, so the next logical step is
                    to talk about the kinds of model air-
     craft available. Years ago, model aviation was
     considered strictly a hobby. The hobby included
                                                                            what we call the “sport” aspect of model aviation.

                                                                                               IF YOU ARE A NOVICE
                                                                            Which is best for you? If you a beginner getting
                                                                            involved with model aviation for the very first
     first building the model and then flying it. In the                    time, my suggestion is to first experience the
     early days, the primary interest was in free flight                    thrill of flying. Don’t let yourself get sidetracked
     and control line models. By the early ’50s we                          by trying to learn basic model-building skills. Get
     began to see the introduction of radio control (RC)                    an ARF or RTF model and get out to the flying
     models.                                                                field as soon as possible. I also recommend that
        As the years passed we saw breakthroughs in                         you try a parking-lot model (the 8- to 14-ounce
     construction materials with the development of
     iron-on coverings and cyanoacrylate (CA) adhe-
     sives and cements that cure in a matter of seconds.
     These advances made building and finishing a
     model aircraft easier and less time consuming.

                           ARF AND RTF MODELS
     These and other innovations in model-building
     technology led to the current popularity of the
     almost-ready-to-fly (ARF) and ready-to-fly (RTF)
     models. Today, it is possible to buy a model that
     is not only fully assembled, but has both the
     motor system and the RC systems installed and
     ready to go. All you need to do is to charge the
     battery and fly.
        Today’s model aviation hobby offers many pos-                       Lil Hornet designed by Merril Brady at MM Glider Tech and sold
                                                                            through David Thacker at Radical R/C Inc. The model has a 232-
     sibilities. You can choose to build a model from a
                                                                            square-inch wing and weighs 9 to 10 ounces, putting it in the
     kit or, perhaps, scratch-build an entire model from                    parking-lot category. Battery is a 7-cell 720mAh NiMH.
     plans. You can finish the assembly of an ARF
     model, or, if you are not interested in building,                      category) for that first model. There are many
                                                                            ARF kits now offered in this category, and models
                                     Left: my 21⁄2-year-old grandson,
                                     Hayden Parkes, holds my replica        of this size are good training planes. Micro
                                     Profile Powerhouse, an 80-square-      indoor-type models should be put off until you
                                     inch free-flight design from the
                                     ’50s. I converted it to indoor elec-
                                                                            learn the basics of flight.
                                     tric flying. The article appears in
                                     the January 2001 issue of RC                    IF YOU ARE AN EXPERIENCED RC PILOT
                                                                            So far I have addressed the needs of the beginner.
                                                                            But what if you are an experienced glow-fuel pilot
                                                                            who wants to enter the world of micro flight?
                                                                            Since you likely have the necessary building skills,
                                                                            you might want to consider building a kit or build-
     Right: on the very light                                               ing from published plans. You still will have to
     side of things is this ultra-
     micro model built by noted
                                                                            learn some of the tricks of electric-powered flight
     Canadian scale modeler,                                                (e.g., battery charging), but that will come with
     Jack McGillivray. It is a
     920 Moto-Aviette Farman,
                                                                            time. Basic flying skills gained from fuel models
     weighing just 1.2 ounce                                                can easily be converted to skills used with micro
     ready-to-fly. It has an 88-                                            electric-powered planes.
     square-inch wing area and
     is powered by 3 50mAh Ni-                                                 Regardless of your modeling background, you
     Cd cells.

                                                                                              CHOOSING YOUR AIRCRAFT

                                                                      Fred Marks, President of FMA Direct, with an Aeronca C-3 look-
                                                                      alike design. This model weighs 6 ounces. Motor is a GWS oper-
                                                                      ating on a 7-cell 250mAh Ni-Cd battery. Area is 260 sq. in. with a
                                                                      wing loading of only 3.3 oz. /sq. ft. Included in the 6 ounces is
                                                                      one of Fred’s new Quantum-6 dual conversion micro receivers.

                                                                      Another popular indoor and parking-lot flyer (in calm wind condi-
                                                                      tions) is Dan Kreigh’s MINI-IFO. It weighs only 4 ounces, with 320
                                                                      sq. in. of area and a wing loading of only 1.8 oz./sq. ft. Powered
                                                                      by a D-1717 geared 1.8:1 on 10 50mAh Ni-Cd cells. A very agile
                                                                      performer, it can literally turn on a dime. A great, fun plane—per-
                                                                      fect for the backyard as well.

                                                                                                          good scales are avail-
                                                                                                          able for less than $100
                                                                                                          from major stationery
                                                                                                          suppliers, such as
                                                                                                          Staples, OfficeMax and
                                                                                                          Office Depot. The scale
                                                                                                          should be used often
                                                                                                          and will be very useful
                                                                                                          in determining the
                                                                                                          correct choice of mate-
                                                                                                          rials and components.
                                            Knowing the weight of
                                            your models and the                       ADHESIVES & COVERINGS
                                           individual components
                                         is absolutely essential
                                                                    When constructing or assembling your models, be
                                       to micro flying. This        sure to use the proper cement for the application.
Pelouze digital scale, purchased at Staples for about $80, does
                                                                    Basic CA cement in thick and thin viscosities is
a good job. It is capable of measuring weights of up to 80
ounces with an accuracy of within 0.1 ounce. It will also read up   used for wood framework assembly. High-stress
to 2,000 grams with an accuracy of within 2 grams. In this          areas (e.g., wing-panel joining, motor and landing-
example, the scale is weighing a GWS R-4P micro receiver and
two Hitec RCD HS-50 sub-microservos. Total weight is 0.7 ounce.     gear mounting) need a 5-minute epoxy. Caution
                                                                    should be taken with models constructed of foam
will need to keep certain things in mind when                       material, since many CA cements will melt the
building and flying small electric-powered models.                  foam. Always test for that possibility using scrap
Weight is of primary importance, as is wing load-                   pieces of foam.
ing. If you have the wing loading too high, the                       Lightweight iron-on covering
model is not going to get off the ground. Since                     material in either opaque or
weight is so important, it is a good idea to buy an                           transparent colors
accurate digital readout scale at the onset. Several

                                                                                              For those who like to build from plans is
                                                                                         this 2.6-ounce model, the Pepper, designed by
                                                                    Dave Robelen. This is in the sub-micro category. It uses a DC 5-2.4
                                                                    coreless motor on 4.2:1 gearing and a 7-cell 50mAh Ni-Cd battery.
                                                                    Servos are the WES-Technik LS-2.4 linear types. Also a marvelous
                                                                    indoor or backyard flyer.

                                                                    Falcon/RCS Technik scale SE5a, built by Stew Meyers of
                                                                    Washington, DC. Model weighs only 3.1 ounces ready-to-fly. Wing
                                                                    area is 160 sq. in., and the wing loading is 2.8 oz./sq. ft. Photo
                                                                    taken by Bob Aberle while attending the Indoor Fly at the
                                                                    National Building Museum in Washington, DC.


                                                                             Hitec's Sky Scooter is a 2- or 3-channel aileron/elevator model
                                                                             for outdoor flying. The 32-inch span plane weighs 16.8 or 18.5
                                                                             ounces depending on whether you are flying the lighter 2-
                                                                             channel version (300mAh Ni-Cd battery) or Pro 3-channel version
                                                                             (600mAh Ni-Cd pack) with throttle. It comes with transmitter and
                                                                             the receiver and servos are factory-installed. Wing loading for
                                                                             the Pro version is 9.65 oz. per sq. ft.

                                                                                                                  The Dumas Aircraft Kestral
                                                                                                                  weighs only 5.5 ounces with a
                                                                                                                  34-inch wingspan.
     is used primarily for the parking-lot flyers.
     Lightweight tissue covering such as Litespan is pre-
     ferred for the micro indoor models. The exact                             concerning all aspects of model-building
     techniques for covering small models can be                               techniques. I refer you to the websites for
     found in several how-to articles. See, for example,                       Tower Hobbies, Horizon Hobby Inc., Hobby
     Dave Robelen’s article in the February 2001 issue                         People, Hobby Lobby Intl. and Northeast
     of Model Airplane News, pages 80 to 82. Also, sev-                        Sailplane Products (see the source guide for further
     eral of the large mail-order houses offer videos                          information).

                                                         TECH TIP
                                                            CHOOSING AN AIRFOIL
          Airfoil choices are also important. Parking-lot or micro indoor flyers perform better with higher-chambered airfoils that permit
          slower flying speeds. Most of the airfoils will have been pre-selected for you by the kit designer, but you should learn which
          airfoils will offer the best slow-flying performance.
             The website,, developed by Stefano Duranti of Italy called Profili, will give you
          good information, and offers free airfoil-drawing software that will run on Windows 95 and later Windows operating systems.
          Some excellent high-chamber airfoils can be found at this website (e.g., Benedek BE6356B, used successfully by micro flier,
          Dave Robelen). This website will be very helpful if you decide to design your own models.

                                                                                                                    The GYMFLYR was designed
                                                                                                                         by Carl Martin (the prop
                                                                                                                         man!) and is being sold
                                                                                                                 through Anything R/C. It has a
                                                                                                                     264-square-inch wing area,
                                                                                                                     weighs 4.8 ounces, and the
                                                                                                                     wing loading is 2.6 ounces
                                                                                                                  per square foot. The motor is
                                                                                                                   a D1717 geared 11.8:1 using
                                                                                                                      a 9.5-inch diameter ARC-1
                                                                                                                 prop running on a Rayovac 9V
                                                                                                                 NiMH battery. The deep under-
                                                                                                                  chambered airfoil makes this
                                                                                                                    a true slow flyer, perfect for
                                                                                                                 indoor flying or outdoor flying
                                                                                                                        in dead calm conditions.


To top