Have ever wanted strangle designers call out 1-degree right-thrust AT ONE TIME another us have tried draw own plans model using published drawings too often incidence dihedral angles given degrees especially true case 3-views real airplanes angles almost universally small 10 40 rarely ever large draw such small angles accurately practically im possible using small protractors us have following method developed drawing small angles simply ac curately first glance process may seem involved complicated However try out few times scrap paper several small angles will find procedure quite simple accurate accompanying table worked out half-degree increments furnish com plete data possible reversing steps method may also used de termine number degrees angle such data given drawing table based following com putations Formula C2 X ir r C360 inches 7r314159 r unknown Completing computation find circumference 36000045 inches has radius 572959 inches Rounding out simplicity circumference 360 inches has radius 573 inches 575/16 inches Substituting degrees inches circumference find circum ference 360 degrees will have radius 57-5/16 inches purposes radius will hereafter referred base line table resulted computations carried out nearest 1/16th inch Angles larger 100 may easily worked out Odd degree dimensions may interpolated table following illustrated example dem onstrates method using table lists procedures required draw small angle Let us assume have small 3view drawing real airplane want draw plans model much larg er 3-view drawing indicates wing set 20 angle inci dence illustration procedure steps indicated circled numbers 1-1/2 degrees incidence 0 tim pie met hod lot dtawrng imall angle Warren Shipp Procedure 1 Consulting table find angle 20 requires arc radius 2 base line 57-5/16 long 1 /2 43 28/8 /16 greater accuracy recommended long est base line possible used Assuming have sheet paper sufficient length draw base line slightly over 28/8 long through point trailing edge wing base line length will prove convenient well accurate 2 Mark point base line juncture wing trailing edge baseline Point 3 Mark dot base line exactly 28/s forward Point established Step #2 Point B 4 Since selected base line 28/t table indicates angle 20 require arc radius 1 Set compass 1 draw arc above base line using Point B center 5 Draw straight line through Point tangent arc drawn Step #4 Continued page 94 RADIUS OF ARC iN INCItES ON BASE LINE OF DEGREES57 5/164328 5/814 5/16 1/2 1/23/8 /8 1 /4 1 1/21 1/21 1/8 /8 2 211/2 2 1/22 1/21 7/81 1/45/8 3 /41 1/23/4 3 1/23 1/22 5/81 3/47/8 4 4 1/24 1/23 3/82 1/41 1/8 5 421/211/4 5 1/25 1/24 1/82 3/41 3/8 b /231 1/2 61/261/247/831/415/8 7 /43 1/21 3/4 71/271/255/833/417/8 8 81/281/263/841/421/8 9 96 3/44 1/22 1/4 9 1/29 1/27 1/84 3/42 3/8 10 107 1/252 1/2 ____ _____________ TRAILING EDGE TABLE FOR DRAWING ANGLES FROM 1/20 TO 100 BASE LINE 28 NOT TO SCALE EXAGGERATED FOR CLARITY Use diagram conjunction table described text become confused flat-bottomed airfoil shown its datum line its bottom surfaceas Clark Y airfoils have datum line intersecting leading trailing edges July1977 37 B WD SHIPP NO OCR TEXT
Edition: Model Aviation - 1977/07
Page Numbers: 37, 94
Have ever wanted strangle designers call out 1-degree right-thrust AT ONE TIME another us have tried draw own plans model using published drawings too often incidence dihedral angles given degrees especially true case 3-views real airplanes angles almost universally small 10 40 rarely ever large draw such small angles accurately practically im possible using small protractors us have following method developed drawing small angles simply ac curately first glance process may seem involved complicated However try out few times scrap paper several small angles will find procedure quite simple accurate accompanying table worked out half-degree increments furnish com plete data possible reversing steps method may also used de termine number degrees angle such data given drawing table based following com putations Formula C2 X ir r C360 inches 7r314159 r unknown Completing computation find circumference 36000045 inches has radius 572959 inches Rounding out simplicity circumference 360 inches has radius 573 inches 575/16 inches Substituting degrees inches circumference find circum ference 360 degrees will have radius 57-5/16 inches purposes radius will hereafter referred base line table resulted computations carried out nearest 1/16th inch Angles larger 100 may easily worked out Odd degree dimensions may interpolated table following illustrated example dem onstrates method using table lists procedures required draw small angle Let us assume have small 3view drawing real airplane want draw plans model much larg er 3-view drawing indicates wing set 20 angle inci dence illustration procedure steps indicated circled numbers 1-1/2 degrees incidence 0 tim pie met hod lot dtawrng imall angle Warren Shipp Procedure 1 Consulting table find angle 20 requires arc radius 2 base line 57-5/16 long 1 /2 43 28/8 /16 greater accuracy recommended long est base line possible used Assuming have sheet paper sufficient length draw base line slightly over 28/8 long through point trailing edge wing base line length will prove convenient well accurate 2 Mark point base line juncture wing trailing edge baseline Point 3 Mark dot base line exactly 28/s forward Point established Step #2 Point B 4 Since selected base line 28/t table indicates angle 20 require arc radius 1 Set compass 1 draw arc above base line using Point B center 5 Draw straight line through Point tangent arc drawn Step #4 Continued page 94 RADIUS OF ARC iN INCItES ON BASE LINE OF DEGREES57 5/164328 5/814 5/16 1/2 1/23/8 /8 1 /4 1 1/21 1/21 1/8 /8 2 211/2 2 1/22 1/21 7/81 1/45/8 3 /41 1/23/4 3 1/23 1/22 5/81 3/47/8 4 4 1/24 1/23 3/82 1/41 1/8 5 421/211/4 5 1/25 1/24 1/82 3/41 3/8 b /231 1/2 61/261/247/831/415/8 7 /43 1/21 3/4 71/271/255/833/417/8 8 81/281/263/841/421/8 9 96 3/44 1/22 1/4 9 1/29 1/27 1/84 3/42 3/8 10 107 1/252 1/2 ____ _____________ TRAILING EDGE TABLE FOR DRAWING ANGLES FROM 1/20 TO 100 BASE LINE 28 NOT TO SCALE EXAGGERATED FOR CLARITY Use diagram conjunction table described text become confused flat-bottomed airfoil shown its datum line its bottom surfaceas Clark Y airfoils have datum line intersecting leading trailing edges July1977 37 B WD SHIPP NO OCR TEXT