by Jack Cherne
April 9, 1999
The wind tunnel test of the 1903 Wright Flyer Replica in NASA Ames Research Center 40 by 80 wind tunnel was everything we expected. We were able to collect most of the data points we planned to collect. We learned some things about the airplane and about the wind tunnel.
Currently we are reducing the data. This means we are looking at all the data points, refining them and choosing which points to plot. When this step is complete we hope to know more about the pitch and rolling moments of the airplane compared to the various displacements of the control surfaces.
One of the things I was surprised to learn was that the fabric on the wings of the airplane billowed considerably at high angles of attack when the wind was underneath the wing. This, in effect, changed the shape of the airfoil. We don't know why yet, it could be that the fabric relaxed in the humid environment, but I'm sure the Wright brothers would have encountered humid weather at Kitty Hawk too. We will be looking for clues to explain more about this when we go through the data.
I was also pleasantly surprised that the drive system, the chain drive, worked as well as it did. I had my fingers crossed about that, but it worked well and we didn't have any difficulty until the last run and then we noticed that there was some heating of one of the bearings, and we shut it down. We only lost one data point. We were disappointed that we couldn't achieve the full rpm of the props due to an electrical problem.
John Latz, one of our members, has all the data and he is inputing it into his computer which has some data reduction software. From this we will plot the measurements taken during the test. One of the common plots we will be doing is lift versus drag another plot will describe the pitching moment. Then we will compare this data with the data from two other scale model tests for which we have data plots.
We were very happy with the support we got we got from NASA. We were pleased that so many people took a personal interest in the test and pitched in.