Control Line: Scale
Mike Stott
THE ENLARGEMENT of 3-views to build from can provide problems for experienced scale builders as well as beginners. I've tried several different methods with varying success. Of the methods that have proven successful I'll describe the ones I like the best.
For any of the methods, you first must find the correct multiplier of the 3-views to come up with the size model you desire. As an example, if the 3-views have a 10-in. wing span and you want a 40-in. wing span on your model, your multiplier would be 4 times all dimensions on the 3-view. I recommend that you use an even multiple from the 3-views, not a number such as "4.379." The simple reason for this is it makes it easier on yourself to enlarge the 3-views. Also, odd multipliers are sometimes annoying to the scale judges who have to work with the figures.
If it becomes necessary to use an odd multiplier to obtain the desired size of your finished scale model, it is recommended that you take the 3-views to a photo lab and have them increased in size, reducing your multiplier. By increasing the 3-views you lessen the number of times you must use the multiplier and, therefore, it should increase the accuracy of your plan drawing from which you will be building. The lower the multiple the less chance for error.
After determining the multiplier I prefer these three methods of handling the actual enlarging process. The first one described is the one I have used most recently. It requires an opaque overhead projector. This can be obtained through your school system, or rented from an office supply and equipment store.
Draw a perfect square around the outside of your 3-views, then place in the overhead projector and shine onto a large piece of paper mounted on the wall. Move the projector back and forth, sideways, tilt it, as required to obtain the proper size using your multiple. Make sure that the projected square is still perfectly square. If it isn't, your plans will be distorted. To correct this, just keep moving and tilting the projector until the square is correct. After everything is perfectly squared up, trace all desired outlines and shapes onto the paper you have mounted on the wall. This method I feel is the quickest and most accurate.
Another method is to use a grid paper over the 3-views. Then, using your multiple, increase the size of the squares when you draw them on your plan paper. In other words, have 1/4-in. grid paper; assuming multiple 4, squares on plan paper would be 1-in. size. Multiple 5 squares would be 1-1/4 in. size. To transfer the drawing, treat each square as an individual picture and copy the lines and curves from the grid squares to the squares on the drawing paper. Take your time and make sure you have everything down correctly and lines cross in the proper places.
The third method again requires that you know the multiplier and also that you have a pair of dividers. Dividers, measuring instruments used frequently by draftsmen and engineers, can be obtained at your local office supply store. The method is to first draw a center thrust-line on the plan paper which you will work off for the fuselage side view. Picking various points, preferably cross sections or former locations from the 3-views, position one point of the dividers on the spinner back plate and the other point on the first former cross section on the 3-view. Changing the divider setting, go to the thrust-line drawn on the plan paper; still assuming multiple 4, measure out four segments—the spacing will locate the first former cross section picked out on the 3-view. Height, width and length items on the 3-views can be done in this manner. I feel this method is the least accurate and most difficult of the three I have described.
Mike Stott 118 F. Wheeler St. North Mankato, MN 56001 No additional text of the primary article ("Control Line: Scale" / CL Scale/Stott) appears on this scanned page beyond the ending already provided in the prior page context. The article on this page ends with the author/address line given previously (Mike Stott, 118 E. Wheeler St., North Mankato, MN 56001).
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