Readily available wind tunnel

[pierre smith]

I decided to add roof-mounted handles so shorter/heavier passengers can more easily board my rather "tall" RV-10...handles like Vic Syracuse and others have.

I didn't want them at odds with the airflow, so I borrowed an old trick to find the airflow direction and mount the handles at that angle for the least drag.

Several drops of old oil above the rear windows and a quick flight showed me what I wanted to know:

[IMG][/IMG]

I then placed two felt-tip black marks parallel to the air stream....voila!

Best,

[Ironflight]

I hadn't thought about that trick for years Pierre - thanks for the reminder. Of course, it means that you actually HAVE to go fly as part of your modification project....isn't that a drag....

[pierre smith]

I used that trick many years ago, when I laid up lower intersection fairings for the Cassutt I'd built, to see what the airflow was doing....worked well.

Surprisingly, the airflow was in a similar direction on both sides of the -10 and was surprised that the spiral propwash wasn't evident like it is on the Air Tractor. The left window on it gets sooty from Jet-A but not the right.

Best,

[GrayHawk]

In Wyoming, you can do this on the ground!