Unfortunately, in order to obtain sufficient visual information from the ground about the descent rate, the maneuvers must be practiced in close enough proximity to the ground as to create considerable danger unless the maneuver is performed in a conservative manner.
2. Organizations involved with training student skydivers have created exercises to be practiced by students to teach them the dangers of these maneuvers near the ground. However, these exercises must be performed at sufficient altitudes as to not be a danger to a student in case the student performs them too aggressively.
This usually results in the student having only an altimeter to compare altitudes at the beginning and end of the maneuvers to determine the altitude lost and to demonstrate the possibility of a dangerous rate of descent near the ground. (Lucky students may find experienced skydivers to accompany them in flight to use their canopies as a visual reference.)
Much like "skyballs" have been used in freefall by skydivers to improve their freefall flying skills, these "swoop streamers" can be used likewise to improve canopy flying skills and knowledge.
1. Crepe paper is by far the easiest, cheapest, and most available material for the streamer itself, and has the important safety feature of a low breaking force with narrow widths. The product selected for this study is a crepe paper streamer packaged as a roll, 81 feet by 1.75 inches. This is one of the common roll sizes available in numerous colors. This roll length was available at Walmart for 48 cents. (Note that some crepe paper products will be in larger rolls, especially at stores that sell more party supplies.)
2. Weights can be nearly any material. Again, we chose Walmart where we found lead fishing sinker weights, product number WEL2-8, a package of 7 egg shaped sinkers approximately one half ounce each, selling for $1.77.
3. Two 1/2 ounce weights were used with this crepe paper streamer which happened to provide a descent rate compatible with a number of canopies. The descent of this streamer with one ounce was timed at 1647 feet per minute.
4. One 1/2 ounce weight was used twice with this length crepe paper streamer. The descent of this streamer was timed at 1102 feet per minute on one descent and 1190 feet per minute on another.
For fine tuning of the weight, inexpensive US coins could be used. The standard weight of a US penny (minted 1982 to present) is 2.5 grams or 0.08825 ounces, and most before 1982 are 3.11 grams or 0.109783 ounces. The US nickel is 5 grams or 0.1765 ounces.
As further work is done, hopefully with the input of other skydivers, we will be able to closely estimate the weight needed to provide a suitable descent rate considering the canopy pilot's skill, canopy, wing loading, and desired maneuvers.
It is hoped that skydivers who provide input will use the same crepe paper length and width, and adjust the only the weight to adjust the descent rate. This will provide fewer variables in determining descent rate, since the exact brand and texture of the crepe paper will produce some variation already.
The following is a list of canopies and wing loadings tested with the streamers.
2. A "breakoff altitude" below which all maneuvers must be ended in order to chose an appropriate landing area must be selected and adhered to.
3. Swoop streamers must be weighted in a manner that cannot cause damage or injury to objects or persons on the ground. (Streamers used with highly loaded canopies will require padding around the weight.)
4. Streamers made from wide material (like the crepe paper used for wind drift indicators) or high drag material will seriously affect the flight of a small canopy if they become attached to the canopy.
5. Streamers must not be made from material that will not easily break, because if the streamer becomes attached to the canopy and the canopy is landed near an obstable, the streamer may become entangled with the obstacle.