[Bob Axsom]

Peter Garrison's Technicalities column in the September 2005 issue of FLYING is the first of a two part drag reduction article with a difference. It is not just another theoretical sermon, he is dealing conversationally with a specific item on his "Melmoth 2" and it gets down to the hands-on application (how)immediately while skillfully tying it to the theory (why). I read it with my RV-6A rudder horn in the back of my mind.

Bob Axsom

 

[rv6ejguy]

The CMARC CFA plots on my 6A show lots of bad stuff in this area so this would be a place to clean up aerodynamically. If you like composites or can come up with flexible fairings, there might be some gains here.

 

[gmcjetpilot]

Drag Plots!

The CMARC CFA plots on my 6A show lots of bad stuff in this area so this would be a place to clean up aerodynamically. If you like composites or can come up with flexible fairings, there might be some gains here.

Can you post those plots? Thanks George

The recent movie about Howard Hughes has a scene where he looks down the side of the plane and says "I want all these rivets flush". You can just look at your airplane and see the drag if you try. Every little bump, mismatched edge, protrusion that is not removed or faired in is drag. The rudder horn is drag but the airflow is turbulent back there and is not as critical, but every little bit counts. One RV builder made the rudder control and horn totally internal!. Not sure how it worked but it was clean. For the RV the single greatest drag maker is cooling drag, which can add 7-10 miles per hour. Cheers George

 

[Bob Axsom]

Is this just "common sense"

Have you seen any wind tunnel or tuft test with and without fairings? The leap from a pretty poor movie and statements about perfectly smooth surfaces being very important to the position that the area of the rudder horns (belcrank?) cables etc. sticking out in the breeze can be ignored because of local area turbulance is a big one in my book. I would never let such a presentation go unchallenged in a design review without test data providing some objective evidence of truth.

Bob Axsom