CHAPTER IV. THE FUSELLAGE OR FRAMEWORK.By the term "fusellage" or frames, that part of the aeroplane which serves as the "backbone" and to which all the other members are attached is implied.The fusellage above all must be strong. The second requisite is lightness. The simplest frame for a model aeroplane is a long straight stick. The cross section of the stick may vary and be either round or square. A careful workman, however, can build them of "I" section like a steel girder. Increased lightness and strength is the result.FIG. 21. A simple "motor base" or fusellage.FIG. 21. A simple "motor base" or fusellage.A single skein of elastic when wound up tends very strongly to twist the framework of the machine out of true. Since the tail and elevator are usually attached to the ends, the adjustment is thrown out to a marked degree and the flight of the machine is liable to be erratic.We have tried building the fusellage of a network of girders such as the Bleriot and Voisin aeroplanes employ. Nothing could have been prettier than these carefully designed and constructed frames with their little struts and guy wires, but we soon found that for plain ordinary everyday efficiency, the simple stick is the best, provided, of course, that it is of the proper size to resist the twist of the rubber.In some cases it is desirable to retain the framework because of the realistic appearance of the model to the larger machines which it gives. The only practical method then is to employ a plain stick backbone to withstand the torque of the rubber and build a false framework around it. The framework need only be strong enough to support the fabric and resist the shocks of landing. This method of construction is best suited to models of the Bleriot and Antoinette types.The only type of frame consisting of a single member which will resist the torque of powerful rubber bands successfully is a tube. The rubber skein is placed inside the tube which may be of wood, paper or aluminum.FIG. 22. Paper Tube Fusellage.FIG. 22. Paper Tube Fusellage. Part of the tube is cutaway to show the rubber skein inside.Paper tubes are excellent for small machines, being exceedingly light and very strong. They are formed by wrapping tough, unglazed paper around a rod of the required inside diameter. The paper is well smeared with glue and wrapped tightly. The rod is afterwards removed. Be sure that the glue is thoroughly dry before attempting to use the tube.In larger machines it is preferable to employ some other means of avoiding the nuisance of a single skein rather than to use a tubular frame. There are several ways of accomplishing this, the best one undoubtedly being to balance the torque of one elastic by an equal torque tending to twist in the opposite direction.FIG. 23. Two methods of gearing a propeller.FIG. 23. Two methods of gearing a propeller.In Fig. 23, a second skein of elastic is geared to the first with equal sized gear wheels. The second skein is placed immediately underneath the first and is equal in length and strength. Placing one skein under the other and not side by side as might be the first tendency allows the propeller to be arranged centrally. The lower part of the same figure illustrates a second method. In this, the propeller is attached to a long shaft, the other end of which is fitted with a gear wheel. Two elastic skeins of equal length and strength are attached to a second gear which meshes with the first. The only disadvantage of this form of motor is the long propeller shaft required. The objection, however, is sometimes outweighed by the fact that it is possible to employ a small gear wheel on the shaft meshing with a large one between the bands so that the action of the elastic is multiplied and a greater number of propeller revolutions secured where the length of the bands is limited and could not be increased in order to bring about the same result.Skids.It requires only very little experience with model aeroplanes to prove the need of efficient skids on the machine. After the rubber band motor has run down, the propeller offers considerable resistance to the forward travel of the machine so that it does not glide properly and causes it to land on its "nose," often damaging the propeller or front planes. At the least, the framework of the machine is strained by such a shock.FIG. 24.FIG. 24.Skids of course weigh something and offer a certain amount of resistance, but the advantages more than outweigh those drawbacks.Skids are usually made of piano wire, split bamboo or rattan. The skids should not be made any larger than is necessary to protect the machine. They do not usually take any special shape but are formed to fit each individual case.
CHAPTER IV. THE FUSELLAGE OR FRAMEWORK.By the term "fusellage" or frames, that part of the aeroplane which serves as the "backbone" and to which all the other members are attached is implied.The fusellage above all must be strong. The second requisite is lightness. The simplest frame for a model aeroplane is a long straight stick. The cross section of the stick may vary and be either round or square. A careful workman, however, can build them of "I" section like a steel girder. Increased lightness and strength is the result.FIG. 21. A simple "motor base" or fusellage.FIG. 21. A simple "motor base" or fusellage.A single skein of elastic when wound up tends very strongly to twist the framework of the machine out of true. Since the tail and elevator are usually attached to the ends, the adjustment is thrown out to a marked degree and the flight of the machine is liable to be erratic.We have tried building the fusellage of a network of girders such as the Bleriot and Voisin aeroplanes employ. Nothing could have been prettier than these carefully designed and constructed frames with their little struts and guy wires, but we soon found that for plain ordinary everyday efficiency, the simple stick is the best, provided, of course, that it is of the proper size to resist the twist of the rubber.In some cases it is desirable to retain the framework because of the realistic appearance of the model to the larger machines which it gives. The only practical method then is to employ a plain stick backbone to withstand the torque of the rubber and build a false framework around it. The framework need only be strong enough to support the fabric and resist the shocks of landing. This method of construction is best suited to models of the Bleriot and Antoinette types.The only type of frame consisting of a single member which will resist the torque of powerful rubber bands successfully is a tube. The rubber skein is placed inside the tube which may be of wood, paper or aluminum.FIG. 22. Paper Tube Fusellage.FIG. 22. Paper Tube Fusellage. Part of the tube is cutaway to show the rubber skein inside.Paper tubes are excellent for small machines, being exceedingly light and very strong. They are formed by wrapping tough, unglazed paper around a rod of the required inside diameter. The paper is well smeared with glue and wrapped tightly. The rod is afterwards removed. Be sure that the glue is thoroughly dry before attempting to use the tube.In larger machines it is preferable to employ some other means of avoiding the nuisance of a single skein rather than to use a tubular frame. There are several ways of accomplishing this, the best one undoubtedly being to balance the torque of one elastic by an equal torque tending to twist in the opposite direction.FIG. 23. Two methods of gearing a propeller.FIG. 23. Two methods of gearing a propeller.In Fig. 23, a second skein of elastic is geared to the first with equal sized gear wheels. The second skein is placed immediately underneath the first and is equal in length and strength. Placing one skein under the other and not side by side as might be the first tendency allows the propeller to be arranged centrally. The lower part of the same figure illustrates a second method. In this, the propeller is attached to a long shaft, the other end of which is fitted with a gear wheel. Two elastic skeins of equal length and strength are attached to a second gear which meshes with the first. The only disadvantage of this form of motor is the long propeller shaft required. The objection, however, is sometimes outweighed by the fact that it is possible to employ a small gear wheel on the shaft meshing with a large one between the bands so that the action of the elastic is multiplied and a greater number of propeller revolutions secured where the length of the bands is limited and could not be increased in order to bring about the same result.Skids.It requires only very little experience with model aeroplanes to prove the need of efficient skids on the machine. After the rubber band motor has run down, the propeller offers considerable resistance to the forward travel of the machine so that it does not glide properly and causes it to land on its "nose," often damaging the propeller or front planes. At the least, the framework of the machine is strained by such a shock.FIG. 24.FIG. 24.Skids of course weigh something and offer a certain amount of resistance, but the advantages more than outweigh those drawbacks.Skids are usually made of piano wire, split bamboo or rattan. The skids should not be made any larger than is necessary to protect the machine. They do not usually take any special shape but are formed to fit each individual case.
By the term "fusellage" or frames, that part of the aeroplane which serves as the "backbone" and to which all the other members are attached is implied.
The fusellage above all must be strong. The second requisite is lightness. The simplest frame for a model aeroplane is a long straight stick. The cross section of the stick may vary and be either round or square. A careful workman, however, can build them of "I" section like a steel girder. Increased lightness and strength is the result.
FIG. 21. A simple "motor base" or fusellage.FIG. 21. A simple "motor base" or fusellage.
FIG. 21. A simple "motor base" or fusellage.
A single skein of elastic when wound up tends very strongly to twist the framework of the machine out of true. Since the tail and elevator are usually attached to the ends, the adjustment is thrown out to a marked degree and the flight of the machine is liable to be erratic.
We have tried building the fusellage of a network of girders such as the Bleriot and Voisin aeroplanes employ. Nothing could have been prettier than these carefully designed and constructed frames with their little struts and guy wires, but we soon found that for plain ordinary everyday efficiency, the simple stick is the best, provided, of course, that it is of the proper size to resist the twist of the rubber.
In some cases it is desirable to retain the framework because of the realistic appearance of the model to the larger machines which it gives. The only practical method then is to employ a plain stick backbone to withstand the torque of the rubber and build a false framework around it. The framework need only be strong enough to support the fabric and resist the shocks of landing. This method of construction is best suited to models of the Bleriot and Antoinette types.
The only type of frame consisting of a single member which will resist the torque of powerful rubber bands successfully is a tube. The rubber skein is placed inside the tube which may be of wood, paper or aluminum.
FIG. 22. Paper Tube Fusellage.FIG. 22. Paper Tube Fusellage. Part of the tube is cutaway to show the rubber skein inside.
FIG. 22. Paper Tube Fusellage. Part of the tube is cutaway to show the rubber skein inside.
Paper tubes are excellent for small machines, being exceedingly light and very strong. They are formed by wrapping tough, unglazed paper around a rod of the required inside diameter. The paper is well smeared with glue and wrapped tightly. The rod is afterwards removed. Be sure that the glue is thoroughly dry before attempting to use the tube.
In larger machines it is preferable to employ some other means of avoiding the nuisance of a single skein rather than to use a tubular frame. There are several ways of accomplishing this, the best one undoubtedly being to balance the torque of one elastic by an equal torque tending to twist in the opposite direction.
FIG. 23. Two methods of gearing a propeller.FIG. 23. Two methods of gearing a propeller.
FIG. 23. Two methods of gearing a propeller.
In Fig. 23, a second skein of elastic is geared to the first with equal sized gear wheels. The second skein is placed immediately underneath the first and is equal in length and strength. Placing one skein under the other and not side by side as might be the first tendency allows the propeller to be arranged centrally. The lower part of the same figure illustrates a second method. In this, the propeller is attached to a long shaft, the other end of which is fitted with a gear wheel. Two elastic skeins of equal length and strength are attached to a second gear which meshes with the first. The only disadvantage of this form of motor is the long propeller shaft required. The objection, however, is sometimes outweighed by the fact that it is possible to employ a small gear wheel on the shaft meshing with a large one between the bands so that the action of the elastic is multiplied and a greater number of propeller revolutions secured where the length of the bands is limited and could not be increased in order to bring about the same result.
Skids.It requires only very little experience with model aeroplanes to prove the need of efficient skids on the machine. After the rubber band motor has run down, the propeller offers considerable resistance to the forward travel of the machine so that it does not glide properly and causes it to land on its "nose," often damaging the propeller or front planes. At the least, the framework of the machine is strained by such a shock.
FIG. 24.FIG. 24.
FIG. 24.
Skids of course weigh something and offer a certain amount of resistance, but the advantages more than outweigh those drawbacks.
Skids are usually made of piano wire, split bamboo or rattan. The skids should not be made any larger than is necessary to protect the machine. They do not usually take any special shape but are formed to fit each individual case.