GALAXY

A Program For Potential Aeromodelers

by: John Konstantakatos, Athens, Greece, 1989

To help the newcomer complete, under supervision, a series of selected projects, in order to gain - without time and material waste - the minimum of experience required to progress independently

Who needs another beginners' program?

There are many good model airplane designs all over the world for training beginners in the field of Aeromodeling, but they are not available to certain countries. On the other side, many of those labelled as "Junior Projects", "Beginner Models" or "Trainers", are not designed by instructors and, unfortunately too often, they have one of the following drawbacks:

The model can't be assembled by the beginner.

The model can be assembled by the beginner, but will log a very short flight of an unpredictable path.

Some commercially available building kits are expensive and some of them can't be reproduced because they rely on the availability of a special “plastic” part or don’t offer a full size plan.

Finally, each instructor, facing pupils with different interests, skills and budgets, establishes his own ideas on how to teach the subject and selects a program to meet each situation. What could be better than creating his own program?

What can GALAXY offer?

This program is composed of four building steps and few specially designed "classic looking" models. Each of the models can be assigned to any of the four steps, so can the steps be modified or even by-passed to meet each individual's needs or time available. As you can see, "GALAXY" offers the individually most important item required by anyone who teaches aeromodeling: FLEXIBILITY.

The models in the "GALAXY" program are named after well-known stars, planets and moons of our Galaxy. They have been selected to fill the lack of suitable projects in our area. They have been designed to be built by a novice and fly. Furthermore the choices between two or more variations offered, suit different skills and material availability. Supervision during building can be kept to a minimum.

They are simple and can be built quickly. They are durable and can withstand the normal'>abuse during trimming sessions, an absolute requirement for introductory models.

Their cost is kept low by carefully calculated cross sections and the use of either full, half, or quarter size of available sheets and sticks (80 mm widths and 1000 mm lengths), a welcome benefit for group building.

Obviously, all this exacts a toll in overall performance, but we must not forget that the young modeler wishes to see his creation flying as quickly and as many times as possible. Maximum duration or flights in strong winds are not our program's objectives.

Last but not least these designs offer flexibility and room for experimentation, two useful items for the eager instructor.

The four steps

1st Step: Initiation

Initiation projects must be simple and produce a flyable result. After the first flight, undoubtedly motivated, the newcomer wants to start a second model which should be already selected and waiting for him. This  model must also be simple, so that can be assembled in a couple of 2-3 hour sessions, yet serious enough to reject the toy image at this point and   lead him deeper into the secrets of building, trimming and flying.

Some instructors propose a glider, while others prefer a rubber powered instead. It doesn't matter which one they choose, as long as it complies with the basic specifications and the project is completed by the individual.

2nd Step : Detonation

The neophyte is now very much interested to select his next choice. This point is very critical if we want to keep him among us. He is usually fascinated by the colorful, fast, noisy, maneuverable R/C models. That is normal, most of us like R/C as well. Furthermore his fresh success has brought him over-confidence and he is even planning to design his own creation. That's normal too.

We must use all of our influence and persuasion to convince him that what the Hobby Shop dealer told him is ready and easy to fly, is not the right choice for his very next project. Of course we should give him something to do.

We can handle that easier, by convincing him that he may redesign a model he has already built. "Modify" is not the proper word to use.

All smaller models in the program are suitable for redesigning. They can offer many variations in airfoil, dihedral, tail, and fuselage options. There are combinations that can keep any novice modeler busy for many weeks while returning tremendous satisfaction. It will all detonate the aeronautical creative power within him.

3rd Step : Preservation

The modeler is still vulnerable. It is our responsibility to point out suitable models, as the smaller rubber powered "P"s and CO2’s according to his skill and personality. Rubber or CO2 powered models offer the advantages of familiarizing with "power" and learning the extra trimming required.

Very young modelers should continue with simple models, while those of age can squeeze this stage to a minimum or go to the fourth and last step of the program.

4th Step : Evolution

Sooner or later our friend will reach this step. Designs like A/3, F1H, F1G, P-30, CO2, 1/2A, P-45, F/F Sport and others - too numerous to mention - are waiting. But not all are suitable. Only those that can be built and flown by the beginner may be selected. We must be very careful with so called "contest winners".

Some contest participation among equivalent models and competitors will definitely polish up building and trimming techniques. However, it is always important to remember that contest winning is not the objective of this program. Models designed after the state of the art, may prove very difficult to build and trim. We don't mean to push the beginner to a degree that may disappoint him and result in negative feelings. During this step the instructor's participation must and can be reduced to the minimum possible.

What's next?

Our fledgling, having mastered the fundamentals, is now flapping his wings with steady strokes, enjoying his "private thermals", but not hesitating to come back for help.

Have we reached our objective?

We have certainly helped a junior to realize what our hobby - sport is all about. Of course it will take some time before we can see if we brought a long life modeler into this world.

Seeds need some time to give fruit. Until then we shall have numerous opportunities to plant some more.

John Konstantakatos

Article first published in CIAM FLYER, the official newsletter of the “Commission Internationale d' Aeromodellisme” of the FAI.

Permission to reprint granded by author and CIAM FLYER, kindly requesting acknowledgement of the source.

 

Model list

Building and flying instructions linked after each photo, are in Greek language, but contain many sketches that can help.

Brief assembly and flying instructions in English language also available

PLUTO

Hand launched glider

Wingspan 240 mm
Balsa construction
Plan
Assembly instructions and Flying instructions.

DIONE

Rubber powered

Wingspan 310 ÷éë.
Balsa construction
Plan 1:1
Assembly instructions and Flying instructions.

VENUS 1

Wingspan 636 mm - Balsa sheet cambered airfoil.
Balsa construction - No paper covering required
Plan 1:1 25 × 70 ĺę.
Assembly instructions and Flying instructions.

VENUS 2

Wingspan 636 mm - Typical flat bottom airfoil.
Balsa and hard wood construction - Wing coverd with tissue paper.
Plan 1:1 one sheet 25 × 70 cm.
Assembly instructions and Flying instructions.

MERCURY 1

Rubber powered
Wingspan 556 mm - Balsa sheet cambered airfoil.
Balsa construction - No paper covering required.
Plan 1:1 one sheet 25 × 70 cm.
Assembly instructions and Flying instructions.

MERCURY 2

Rubber powered
Wingspan 566 mm - Typical flat bottom airfoil.
Balsa construction - Wing coverd with tissue paper.
Plan 1:1 one sheet 25 × 70 cm.
Assembly instructions and Flying instructions.

MERCURY CO2

Mercury airframe with CO2 motor.
Modification instructions and Flying instructions.

JUPITER 1

Towline glider
Wingspan 965 mm - Jedelsky type airfoil.
Balsa, plywood and hardwood construction - No paper covering required.
Plan 1:1 one sheet 28 × 81 cm.
Assembly instructions and Flying instructions.

JUPITER 2

Towline glider
Wingspan 975 mm - Typical flat bottom airfoil.
Balsa, plywood and hardwood construction - Wing and stab covered with tissue paper.
Plan 1:1 one sheet 28 × 81 cm showing wing only. Jupiter 1 plan also required for fuselage plan.
Assembly instructions and Flying instructions.

JUPITER 3

Wingspan 975 ÷éë - Typical undercambered airfoil.
Balsa, plywood and hardwood construction - Wing and stab coverd with tissue paper.
Plan 1:1 one sheet 28 × 81 cm showing wing only. Jupiter 1 plan also required for fuselage plan.
Assembly instructions and Flying instructions.

SATURN

P-30 (rubber powered)

Wingspan 760 mm - Typical flat bottom airfoil.
Balsa construction - Wing and stab coverd with tissue paper.
Plan 1:1 two sheets 28 × 81 cm.
Assembly and flying instructions in brief

 

Brief instructions

Pluto and Dione

  • Although free flight models trim easier for a turning glide with their stabilizer tilted, the instructions of these two models ask for squared flying surfaces, as building true and square models are more vital lessons at this stage than trimming for optimum glide.
  • Glue: 5 min epoxy glue recommended
  • Trim tabs: Cut from French coffee’s airtight cover (thin aluminium), or from hard carton.
  • Expect that these models will have some warps and/or misaligned surfaces, so they will be difficult to trim. The goal in this stage is : achieve a flight of a descent pattern, without damage. Duration or optimum glide angle is not important. Pluto
  • Fuselage: 2-3 mm hard to medium balsa stick by 10 mm (3/32-1/8” X 3/8”), 250 mm long
  • Wing and tail: 0.8-1.2 mm medium to light balsa sheet. If 3” or 80mm wide, 250 mm long, if 4” or 100mm wide 250 long for one model or 385 mm long for two models).
  • Dihedral angle: 30 mm on this length = 30 degrees. Score undersurface of wing at the dihedral brake with sharp knife halfway through wood thickens. Bend carefully tips upward, do not break wood completely. Force glue with toothpick inside groove, also apply one thin coat of glue on upper surface of dihedral joint.
  • Some (or all) of the nose ballast should be modelling clay to help trimming process.
  • Launch it either by hand throw or small hand held catapult. Release the model with one wing tip lower, and nose higher in relation to the horizon for a smooth transition at the top of the climb. Try both left and right pattern launches. It doesn’t matter whether the model glides straight, right or left, as long as it is good looking and satisfying to the first time modeler. Adjust radius of turn, and/or extreme deviations during climbing by bending rudder trim tab.

Dione

  • Fuselage: 3 mm medium to hard balsa stick, 3/8” or 10 mm wide, 420 mm long
  • Wing and tail: 0.8-1.2 mm sheet medium to light balsa. If 3” or 80mm wide, 450 mm long. If 4” or 100 mm wide 320 mm long.
  • Dihedral: 30 mm on this length = 30 degrees. Builds similar to Pluto wing.
  • Draw centerline on bottom of wing, draw also two parallel lines 1,5 mm each side of centerline. The two outer lines depict wing-fuselage contact area (do not glue wing to fuselage).
  • Glue wing saddle just outside one of the outer lines, either side is good at this point.
  • Glue trim tab on the left trailing edge of center panel. From this moment the wing is oriented, and the saddle should always be touching the same side of fuselage.
  • Attach wing saddle to fuselage side with two small rubber bands rolled in advance over the fuselage stick.
  • Prop assembly similar to the AMA Cub (Delta Dart, etc.) Beware that there are many similar assemblies from different manufacturers, but not all with the same down thrust. Check over plan and file nose of stick at an angle if necessary to end with the required down thrust.
  • Rubber motor 1/8” or 3 mm thick about 55 centimeters long before tied to a loop.
  • Slide the wing forward or aft to correct a dive or a stall under power. If too far aft a position seems desired, and down thrust is OK, its better to add a small amount of ballast (modelling clay) to the nose.
  • Start by launching the model with 50-100 turns, and if all seem in trim, then increase the turns by 100 on every succeeding flight up to the motors limit. Bend wing’s trim tab down to smooth a violent left turn/spiral. Doesn’t matter if the model flies with a left or right climbing pattern. There is no need to struggle for a flat glide.
  • If the back hook (pin) is left straight (without the final horizontal bent), the motor will slide off at the end of run and hang only from nose hook, thus forcing the model to dive to the ground (a kind of dethermalizer).

Venus gliders

The designs are based on the most commonly available wood sizes i.e. 80 mm wide X 1000 mm long sheets, or 1000 mm stick lengths.

One may choose to modify the wood sizes on the fuselages, or may choose to combine either fuselage (Venus 1 or 2) with the wings of Venus 2 and 1 respectively. These choices are dictated mainly from the availability of the required wood sizes, or of other size/material combinations, and/or the availability of covering material, and/or the time to complete the assembly of the most time consuming Venus 2. Traditional tissue/dope or lightweight, heat shrinkable wing coverings are both good choices for the Venus 2.

Trim the model for a wide turning glide. Do not try to launch all the way to the top of the towline length. Release the model as soon as it starts to bank. Do this by letting the towing device of your hands before a dive occurs.

Mercury rubber powered models

There are two different wings, but only one fuselage. The only modification that could be proposed is to built a lighter horizontal stabilizer from 3mm square balsa and cover it with tissue. If sheet balsa stabilizer used, it may have to be straightened (or made warp proof) by gluing two 1,5-3 mm balsa strips under or above the extreme left and right ends (at the stab tips).

Trimming for proper glide angle is achieved by adding removing noseweight, or by modifying the wing pylon to a sliding option (please refer to the instructions of Mercury CO2).

Yes, this series of models can be easily converted to CO2 power. With some preplanning one can convert from one power mode to the other and vice-versa without cutting or gluing anything on the structure.

Two points of attention:
The sparless wings of Venus 1 and Mercury 1 and the wings of the Venus 2 and Mercury 2 with their balsa only spars are not meant for flights in anything but calm or very light breeze winds. On the contrary all four models have shown good resistance to hard landings, mainly because the wings are attached to the fuselage with very small/light rubber bands, just enough to keep the wing in place under the flying forces involved.

Also since these models are not equipped with a dethermalizer, avoid flying during the time of the day that there is thermal activity.

Jupiter gliders

These models are not of the contest performance type that you see in the magazines along with trophies. They are designed to introduce the modeler to: a) a more difficult building stage, b) to the old fashion straight hand towing with an auto-rudder, and finally c) to the mechanical dethermalizer.

The Jupiter family has 3 versions on two plan sheets. All three versions use the same fuselage, as shown on sheet #1 at 1:2 scale. The Jupiter 1 uses a Jedelsky type of wing, and curved sheet stabilizer.

The Jupiter 2 and Jupiter 3 use different built up wings and the same built up stabilizer. On plan sheet #2 one can see the two different airfoils, a flat bottom for the Jupiter 2 and an undercambered for the Jupiter 3. Both wings have the same overall dimensions, and to save space on the paper, they are drawn half each on the same plan sheet #2.

One could think they are exactly the same, but there are differences as to how the main spars are presented. The Jupiter 2 has the main spar flush with the top of the airfoil (see left outer panel and left center panel), while the Jupiter 3 has the main spar flush with the bottom curve of the airfoil (see right outer panel and right main panel). There can be a fourth airfoil, by drawing a straight line on the bottom of the undercambered one.

Saturn P-30

This is a straight-forward in size P-30 with a constant chord, flat bottom airfoil wing with a simple V form dihedral. No effort was made to build it to the minimum weight limits. This is an introductory model to introduce to the handling of more powerful rubber. It was designed having in mind that its no easy to always have the same rubber cross sections available, as it usually happens in many places (hobby shops). Furthermore the experimenting with different rubber cross sections is a lesson in itself. This may answer the question why the different rear peg positions.

This model is very stable and can achieve flying times that are very rewarding compared to the building effort invested.

One can remove the rubber and add a CO2 motor of the 0.27 c.c. size with the same size prop (9 1/2”). Permanent modifications would be required though to achieve proper balance. On this model is shown the dethermalizer with the burning fuse. Extreme caution is recommended if using this type of dethermalizer. Fire risk for the plants at and around the field.

MERCURY CO2

One of the models suitable for being powered by a CO2 motor is the Mercury (either #1 or #2). Any CO2 motor around 60 mm3 with its factory supplied (free flight) tank is recommended. Please refer to the additional A4 size plan for the motor/tank mounting options, and the wing’s pylon modification.
Motor mounting
The motor can be mounted in many different ways. The following instructions show two methods for allowing a changeover from rubber to CO2 (and vice versa), without altering anything permanently at the nose.

First method: One of the recommended mounts is a thin aluminium or other thin metal piece with two sides at 90o angle (“L” cross section), or alternatively a piece with a “T” cross section. Drill the front part of the aluminium and mount the motor (with bolts and nuts) as close as possible to its side flap. Trial fit this part of the mount over the side of the nose of the model, and you will find it is necessary to add a wooden spacer between the mount and the fuselage to achieve alignment of the motor’s centerline with that of the model’s.

When this is done, mark and drill a hole through the aluminium and spacer at a position where all together can be bolted on the fuselage side through the existing hole (longer bolt needed).

Down thrust is easily adjusted by loosening-tightening the bolt. You may also find helpful to glue a piece of sandpaper on the inside surface of the aluminium to increase friction. Side thrust can be adjusted by bending slightly the metal mount or adding washers between the motors backplate and mount.

Although the plan doesn’t show the “T” section mount, this is considered a better choice to the “L “ section mount, because the former usually doesn’ t need a spacer, as its offset is sufficient for a direct contact with the fuselage side.

Second method: The motor is bolted on two hardwood beams of suitable cross section (see plan). Clamp temporarily the two sticks, one on each side of the fuselage, and check if the motor’s bolt spacing is matching (approximately) the center of the beams front face. If the thickness of the sticks is enough to allow the mounting screw to go through the wood without splicing it, then mark and drill the side hole FIRST to match the position of the existing fuselage bolt.

At this moment you should decide if the two sticks will be equally protruding forward, or at a slight asymmetry for side thrust. Glue a small piece of sandpaper on the inside surface of the wooden sticks to increase friction. Use a bolt long enough to sandwich the two wooden sticks on the model’s nose. Then drill two holes on the front end of the two hardwood beams and mount the motor with sheet metal or wood screws. Drop some thin cyano glue in the holes to strengthen the wood.

Down thrust is easily adjusted by loosening-tightening the bolt. Side thrust can be adjusted by adding a washer or removing some wood on the appropriate side with a file.

Tank and Wing mounting
It is most sensible to position the tank in front of the wing’s pylon, where it can be secured by a rubber band or thin wire over an extra toothpick inserted crosswise. However, due to the extra weight of the motor and tank, the wing’s position should be brought forward to achieve proper balance. It is highly advised to choose the recommended pylon attachment with rubber bands, for easiness of repositioning. Alternatively, if the pylon/wing can’t be moved, you can still bring the C.G. to the required position, by repositioning the tank on the side of the pylon, or behind the wing, and/or adding tail weight.
Electric conversion
The Mercury models can be converted to electric. But there are not yet any relevant instructions ready.

 

 

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