stunthanger.com

Building Tips and technical articles. => Building techniques => Topic started by: Dennis Moritz on November 16, 2007, 07:22:37 AM

Title: Wing offset/flap area/flap tab... ???
Post by: Dennis Moritz on November 16, 2007, 07:22:37 AM
I've got a Tanager wing jigged up. Easy enough to add a half inch to the inside wing half. There are 8 bays. 1/16 inch extra space per bay makes for a half inch. I noticed Al Rabe added a half inch differential to the inside of the Mustunt. Many other designs add a similar differential. The Fancherized Twister on the other hand adds extra area to the outside wing flap. Often club members find a tab on the outside flap helps with various trimming ills. Similar in concept to the extra area built into an FT flap. So. More wing are on the inside? Extra flap area on the outside? THE TAB? What do people think?
Title: Re: Wing offset/flap area/flap tab... ???
Post by: phil c on November 16, 2007, 03:15:58 PM
build the sucker and then see what it needs to trim out.  There is no way to pre-calculate these little trim fixes.  Too many interactions, and they are too small to put accurate numbers on.  Like rake has been well worked out.  Use the best number you can come up with from the various calculators as a starting point.  Wing offset and tip weight work together.  Kind of depends on which you prefer, not that one or the other is demonstrably better than the other.  If half an inch longer on the inboard wing lets you knock off an ounce of tipweight that is probably a good tradeoff.  Then you might have to add an eighth inch of chord to the tip of the outboard flap, or trim the inboard flap slightly.  Trimming the trailing edge looks much better than warts on the tip of the flap and can be nearly invisible.  Just paint the trailing edge black.
Title: Re: Wing offset/flap area/flap tab... ???
Post by: Dennis Moritz on November 16, 2007, 05:20:31 PM
Yes, Phil! (I happen to like those ugly soda can tabs.) Thanx.