

Dec 01, 2002, 01:01 PM  

This site has almost all the answers to any questions anyone might have...
http://www.charlesriverrc.org/articles_modeldesign.htm . but generalizing, there's few absolutes in model aircraft design. Areas and moments and angles are variable to a large extent, depending on what you want from the plane, or just feel looks good. The only "shoulds" I pay attention are the c.g. should be in the right place, there should be no warps in the surfaces, and the controls should have reasonable deflections. . My best photo plane is a collage of parts.. wing from a 2m, USPS mailing tube fuselage, arrow shaft booms, and a TLAR inverted vtail. A couple pages on my sites relative to this.. http://home.earthlink.net/~pjburke1/cameraplanes.htm http://www.angelfire.com/indie/aeros...hotoPlane1.htm . PJB's Seriously Aeronautical Stuff: http://home.earthlink.net/~pjburke1/aindex.html Sparky Paul: http://www.angelfire.com/indie/aerostuff 
Dec 01, 2002, 04:43 PM  
Cincinnati, OH
Joined Aug 2002
767 Posts

John P,
I checked out the Charles River site Sparky recommended and the Quick VTail Sizing site, specifically. http://www.charlesriverrc.org/articl...tailsizing.htm The equations provided there are aerodynamics based and easily derived vs more experience than physics based rulesofthumb sometimes provided elsewhere. From my perspective the key points are that you should approach the model design as you would a conventional tailed model in terms of C.G., tail volume, etc. The VTail areas and angles can then be calculated to give the equivalent horizontal and vertical stab moments. With that approach the total stab area, that is, the sum of the two Vtail surfaces or the sum of the horizontal and vertical conventional surfaces, should remain the same. For instance, if you are designing a glider with a high aspect ratio wing where the horizontal and vertical stabs would each have an area of 75 sq. in. for a total of 150 sq. in., the equivalent VTail stab would have two 75 sq. in. surfaces at an angle of 45 degrees from the horizontal. On the other hand, if you are designing a sport model with a lower aspect ratio wing where the horizontal would normally be 100 sq. in. and the vertical 50 sq. in., again for a total tail surface area of 150 sq. in., the equivalent Vtail area would be 150 sq. in. with two equal 75 sq. in. surfaces. This time the equavilent angle above the horizontal should be ~35 degrees. 
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