20191105 Report.pdf

…The Cutting Edge in Drum Technology

Documentation of Sail Prototype Testing

20191105

Morton, IL 61550

Abstract

This report documents the sail prototype testing during the week of 20191027 - 20191104 in the testing tower at the Fugate Morton, IL facility.

Background

Three different sail models were fabricated during the months of September and October of

2019. The Sails are designated A, B, and C. Sail A is symmetrical, Sail B is asymmetrical, and

Sail C is a dual airfoil.

Materials, Methods, Observations, and Discussion

Chime assemblies were suspended in the testing tower. Both chime assemblies have a 4 point node connection, a rigid connector above the node puck, a rigid connector above the striker, a small striker, 75d polyurethane dampening material, and rope tethers.

The sails consisted of Schaeffer tracks for ease of adjustment and changing out the sails. The scaffold was dismantled and a telehandler was used access the sails. Observations were made with pen and paper and occasional video documentation. A variety of weather conditions were present during the observations. The team witnessed rain, snow, ice, and warmth as well as dynamic wind conditions from calm to moderately strong.

Formal observations were made of each sail and its inherent characteristics. Sail A was observed

108 times, Sail B was observed 120 times, and Sail C was observed 164 times. During these observations the car on the Schaeffer tracks were moved into selected positions on both the rotator side and the tether sides of the sails. Bottom car (tether side) and top car (rotator side) are positions that relate to the Schaeffer track.

The mode and average of the sail observations were selected to be displayed for the strike intensity, bottom car position, top car position, and wind speed (see Table 1). For strike intensity we defined the strikes as none (no, zero, 0), light, medium, and hard. No strikes meant that the striker did not engage the chime tube and did not make any sound, though the sail could have been moving. Light strikes were defined 59 dBA and less, medium strikes were defined as 60 –

69 dBA, and hard strikes were defined as 70 and above dBA.

All of the wind speeds for this study were gleaned from the weatherlink.com website. As we made the observations, we noted the time and subsequently went into the historical data provided by weatherlink in silico for this time period. These wind speeds represent the average wind speed for a given time. No peaks or gusts are taken into account for this study. Also, each wind speed is taken from a particular anemometer associated with a certain corbel (north or south).

Observation Strike Intensity

Bottom Car Position

Top Car Position Wind Speed

A Mode With 0 Strikes 0.00 4.00 8.00 10.00

A Mode Without 0 Strikes 5.00 4.00 8.00 10.00

B Average 3.31 4.82 8.12 9.48

B Mode With 0 Strikes 0.00 4.00 8.00 12.00

B Mode Without 0 Strikes 5.00 4.00 8.00 12.00

B Average 2.13 4.03 8.45 9.16

C Mode With 0 Strikes 0.00 6.00 8.00 11.00

C Mode Without 0 Strikes 5.00 6.00 8.00 11.00

C Average 4.00 6.36 7.00 9.98 Table 1. Numbers gleaned from sail observations during the week of 20191027 – 20191104.

Figure 1 is a graphic representation of Table 1. By looking at this data we can see that most of the time there is no striking happening on any of the sails. All of the sails have a mode of 0 for the strikes. So in order to better visualize the data, it was also treated without the 0 strike observations. A 0 strike observation is a time in which an observation was made and no strikes were realized between the tube and the striker.

Thus, with the 0 strike observations Sail A was observed 108 times, but by removing the 0 strike observations there were only 75 observations made in which Sail A was striking the tube at any given intensity. Similarly, Sail B had a total of 120 observations made on it with all of the 0 strikes included. By removing the 0 strike observations from Sail B there were only a total of 59 observations made in which Sail be generated strikes of any intensity. Also, Sail C was observed a total of 164 times including the times it was not striking (0 strikes). When the 0 strikes were removed from the Sail C data, there were 114 observations made where Sail C was engaging the chime tube at any intensity level.

By treating the data in this way, a few things were learned. One is that most of the time the sails do not result in a motion that causes the striker to strike the tube. Also, that most of the strikes occurring from all 3 sails in the observed wind conditions are of a medium intensity. It is also demonstrated that as a percentage of the total number of observations in relation to the total number of observed strikes in the experienced wind conditions that Sail A resulted in strikes about 69.5% of the time, Sail B resulted in strikes about 49.2% of the time, and Sail C resulted in strikes about 69.5% of the time.

However, looking at the average of the strike intensity, it is apparent that Sail C (in the observed wind conditions) is the most powerful sail of the 3. That is followed by Sail A, and then Sail B.

Figure 1. Graphic representation of strike intensity, car positions, and wind speeds.

Furthermore, by examining Table 1 and Figure 1, the positions of the tether cars can be extrapolated. Sail A and Sail B were both tested under very similar car positions. For example the most tested position for the bottom car was 4 and the top car was 8. For Sail C, most of the time the bottom car was on 6 and the top car was on 8. So it seems on the mode and the average of the data that the top car position and the bottom car position optimize when the bottom car is just slightly forward of the top car.

Strike Intensity Top Car Position

0.00 2.00 4.00 6.00 8.00

10.00 12.00

Sail Analysis

Strike Intensity Bottom Car Position Top Car Position Wind Speed