Reference / Paper · 2014
Peak of Flight #372: Comparing A Cluster of Two Parachutes Versus One Parachute
Apogee Components' Peak of Flight newsletter, issue 372 (2014-08-26).
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- apogee-components
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Reference / Paper · 2014
Apogee Components' Peak of Flight newsletter, issue 372 (2014-08-26).
Apogee Components' Peak of Flight newsletter, issue 372 (2014-08-26).
In This Issue Comparing A Cluster of Two Parachutes Versus One Parachute Ashley Van Milligan R&D Event, NARAM-56 Also In This Issue Free Shrox Plan: The “Dark Matter Probe” Cover Photo: Water rocket using the specially-design Strato Fins Pick up your own set at: http://www.apogeerockets.com/Rocket_Kits/Water_Rockets/StratoFins Apogee Components, Inc. — Your Source For Rocket Supplies That Will Take You To The “Peak-of-Flight” 3355 Fillmore Ridge Heights Colorado Springs, Colorado 80907-9024 USA www.ApogeeRockets.com e-mail: [email protected] Phone: 719-535-9335 Fax: 719-534-9050 ISSUE 372 August 26, 2014 Comparing A Cluster of Two Parachutes Versus One By Ashley Van Milligan The objectives of the work To find out the size of 2 parachutes that will give me the same descent rate as one parachute. The reason I did this is it was the TARC challenge was to use 2 parachutes instead of one and two parachutes have to have the same descent as one parachutes. The first parachute weighed 5.6 grams. The second and third weighed 7.3 grams. So I added clay to the first parachute. We went to the park and we launched the first parachute out of a water rocket. We had to use a water rocket because it is cheaper than a model rocket, and there was more room inside for parachutes and the altimeter. The approach taken First I found the area of an 18 inch parachute with my dad’s help. Then I found the area of two 12.72 parachutes. Two 12.72 area parachutes has the same area as an 18 inch parachute. Next I numbered each parachute 1, 2, and 3. I weighed them. Water Rocket Prep and Flight Parachute Construction Continued on page 3 About this Newsletter Newsletter Staff You can subscribe to receive this e-zine FREE at the Apogee Components web site (www.ApogeeRockets.com), or by sending an e-mail to: [email protected] with “SUBSCRIBE” as the subject line of the message. Page 2 ISSUE 369 Writer: Tim Van Milligan Layout / Cover Artist: Tim Van Milligan Proofreader: Erin Card J U LY 1 5 , 2 0 1 4 Continued from page 2 Two Cluster vs Single Parachute, cont. Finding The Descend Speed We put an AltimeterThree in the rocket’s nose cone. We flew the rocket two times with each parachute size. We didn’t care about the peak altitude, we only cared about the descent rate. On the graphs (shown on the next page) I drew a straight line in the part where the parachute was coming down. This evened out all the bumps in the descent. You can also see that the parachute was falling nice and steady. Then we flew the second and third parachute together to equal the weight of one parachute. We flew this out of water rocket. We only got data on 2 flights for each size, because the rocket kept crashing, since it didn’t have an ejection charge like a model rocket motor. The nose cone had to fall off, and it didn’t, so the rocket kept crashing. The altimeter was OK, but sometimes the nose cone broke and had to be replaced. Then we looked at the data and found out that the 12 inch parachute wasn’t falling slow enough, so later we made an 14 inch parachute and repeated the experiment. Now I picked two points on the line. I subtracted the first two numbers and wrote the time down. Next I subtracted the second two to numbers and wrote down the altitude between them. After that, I divided the altitude from by the time. This is the descent rate of the rocket. • The descent rate of the first flight of the single 18 inch parachute was 15.25 ft/sec • The descent rate of the second flight of the single 18 inch parachute was 13.66 ft/sec • The descent rate of the first flight of the cluster 12.72 inch was 15 ft/sec • The descent rate of the second flight of the cluster 12.72 inch was 16 ft/sec • The descent rate of the first flight of the cluster 14 inch was 11.66 ft/sec • The descent rate of the second flight of the cluster 14 inch was 13 ft/sec LEFT: These are pictures of the nose cone, and how the altimeterThree was mounted into it. The AltimeterThree talks to a smart phone using Bluetooth. In the top-left photo, you can see how clay was added to make all the rockets the same weight. Continued on page 4 We’re Paying Cash For Great Articles for This Newsletter Are you a writer looking for some serious pocket change? We’re paying up to $350 for good how-to articles for this newsletter. If you’re interested, see our submission guidelines on the Apogee web site. www.ApogeeRockets.com/Newsletter/Newsletter_Guidelines ISSUE 369 J U LY 1 5 , 2 0 1 4 Page 3 Continued from page 3 Two Cluster vs Single Parachute, cont. Altitude (feet) Altitude (feet) Flight #1 18” Diameter Parachute (3, 76.0) Flight #2 18” Diameter Parachute (4, 53.0) (7, 15.0) (7, 12.0) Altitude (feet) Altitude (Feet) Flight #1 Two 12.72” Diameter Chutes (3,49) Flight #2 Two 12.72” Diameter Chutes (3,69) (6,4) (7,5) Flight #2 Two 14” Diameter Parachutes Altitude (feet) Altitude (feet) Flight #1 Two 14” Diameter Parachutes (3, 49.0) (6, 109.0) (10, 57.0) (6, 14.0) Time (seconds) Time (seconds) Continued on page 5 Page 4 ISSUE 369 J U LY 1 5 , 2 0 1 4 Continued from page 4 Two Cluster vs Single Parachute, cont. The equipment used: Then I averaged the descent rates. 1. AltimeterThree prototype (borrowed) 2. Strato Fins 3. Bicycle pump 4. Soda bottle 5. iPhone and AltimeterThree App 6. Parachutes - custom made. 7. Custom-made plastic nose cone for the water rocket 8. Kevlar shock cord 9. Jolly Logic altimeter mount 10. Microsoft excel • The average descent rate of the single 18 inch chute was 14.56 ft/sec • The average descent rate of the cluster of 12.72 inch chutes was 15.5 ft/sec • The average descent rate of the cluster of 14 inch chutes was 12.33 ft/sec Conclusion: The facilities used: • The two 12.72 parachutes fell too fast and the 14 inch parachute fell too slow. I did my experiments at a local park. • So a 13 inch chute would probably match the 18 inch chute the best. The money spent on the project (budget): List of any related R & D Reports previously entered by the author, if any, with brief summaries: No previous reports submitted. Strato fins $11.76 Snap swivels $3.00 Parachute materials $3.00 Total = $17.76 The data collected: References to previous work done on the subject, found in research preparatory to this report “Comparison Of The Number Of Parachutes Versus Descent Rate” by Allison Van Milligan. NARAM-52 R&D Project. July 2010 Model Rocket Design and Construction, 3rd Edition, by Timothy S. Van Milligan. Copyright 2008. Join Tripoli.org Mention Apogee Components • • • • My Dad helped me to make these graphs from the data downloaded from the AltimeterThree Further work that would clarify or extend the results obtained I did not make a 13 inch chute to confirm that it would fall at the same descent rate as an 18 inch chute. In the future I would do that if I had time. • Soft, flexible foam padding provides superior protection from cracking • Conforms to the egg to eliminate pressure points • TARC style for two eggs available • Lightweight & reusable Made by: ISSUE 369 J U LY 1 5 , 2 0 1 4 www.ApogeeRockets.com Egg-Payload Protectors Page 5 Shrox Plan: The “Dark Matter Probe” By Shrox Download the RockSim file (which includes the parts list) at: www.ApogeeRockets.com/Downloads/DarkMatterProbe.zip • Designed to ignite the top motor in two-stage rockets. • Provides an easy way to stage composite propellant motors • Fires off igniters after a preprogrammed amount of time following liftoff • G-switch senses liftoff and insures against a false launchdetection • Small, lightweight design is great for skinny rockets • Easy-to-use, and will fire off any igniter, including clusters! www.ApogeeRockets.com Battery, battery connector, mounting board and igniter are not incuded. Page 6 ISSUE 369 J U LY 1 5 , 2 0 1 4 www.ApogeeRockets.com Staging Electronics