Oil Flows / Klaus is awesome!

Hey Guys,

I assume everyone has seen it already, but just in case.  You need to check out Lynne Wainfan's article on Klaus Savier and the Determinator (December Experimenter).  Prepare to have your mind melted.

Anyway in the article Lynne describes Klaus' secret recipe for oil based flow visualization.

"...special dark colored oil is put on the airplane before flight.  After landing the oil tracks show where the air was, or was not.  Klaus has a finely tuned mixture for his oil: He starts with carbon black, the fine powder that is added to paint to make it black.  Carbon black is available on the Internet and in paint shops.  To this, he adds motor oil which is viscous - a handy trait that helps it not fall off the airplane.  Then Klaus reduces the mixture with diesel fuel or kerosene, but this combination has too much surface tension.  To counteract that problem he adds a lot of dish soap...One begins to understand exactly how obsessive engineers are about visuaizing airflow.  (I have found that the dishsoap has made the carbon black cleanup a breeze)."

I was really impressed by the combination of Lynne's engaged and researched writing and Klaus' willingness to share.  I ended up all pumped up about the topic, luckily with Justin Gillen doing all this Cassutt flying to get up to speed for PRS it seemed an opportunity we were missing.  So we ended up getting out the oil again and doing some visualization work.  Below are some pictures of what we found.  Yes we are intentionally leaving out the most interesting pictures :).

Elliot and Jenn

Tangotimemachine separation at cooling exhaust

Tangotimemachine separation at cooling exhaust, opposite side

Miss Demeanor cowling above inlet

Miss Demeanor belly cooling exhaust 

Ferrying Miss Demeanor

On Saturday Justin Gillen and I had the opportunity to ferry an awesome airplane for a friend from Stead to Mojave.

Miss Demeanor is a long time racer.  The airplane currently is configured with a stock Cassutt vertical and horizontal and a Craig Catto tapered wing that was originally on outrageous.  The wing installation was well done and addressed a lot of the handling concerns of the Cassutt.  The limited throw of the aileron (5" at the stick, vs 12" in pitch) helped liven the roll axis, and balanced that axis against the high rates a Cassutt is historically known for in pitch.  This airplane also has a lot of stiction in the pitch axis which also helped to dampen that axis.  The airplane has no dihedral effect, and is even lighter than my stock cassutt was directionally, probably due to the longer wing.  With light rudder forces, no stick free directional stability, and little to no stick fixed directional stability the airplane had to be actively flown the whole time, which was fun.  There seemed to be some difference between the incidence of the vertical, the thrust line, or the rig of the rudder pedals as the rudder displacement required to center the ball varied greatly with airspeed and power setting even between 150 and 220 MIAS.

I really enjoyed the upright cockpit and great over the nose visibility of the airplane compared to my racer, it truly felt like a gentleman's airplane.  I landed the airplane by coming over the fence at 80 MIAS and touching down in a tail low wheelie.  Conveniently I found the tail only needed to drop another few inches before the tailwheel made contact and the hard part of the landing was effectively over, the airplane has a fixed non-steerable tailwheel.  A great airplane and a well behaved tail dragger.  What a great time!!