Reference / Paper · 2006

Peak of Flight #165: Making Fin Slots With A Dremel

Apogee Components' Peak of Flight newsletter, issue 165 (2006-08-14).

Author: Tim Van Milligan / Apogee Components
Year: 2006
Type: Reference / Paper
Credit: Apogee Components, Inc. (Colorado Springs, CO) — Peak of Flight newsletter

peak-of-flight
apogee-components
model-rocketry

Apogee Components' Peak of Flight newsletter, issue 165 (2006-08-14).

I S S U E 1 6 5 - A U G U S T 1 4 , 2 0 0 6 Fin Slots Made Easy: Cutting Your Own INSIDE: • Making Fin Slots with a Dremel® • Maximizing Altitude in Windy Conditions • Web Site of the Week • Apogee Photo Contest Results 1130 Elkton Drive, Suite A Colorado Springs, Colorado 80907 USA www.ApogeeRockets.com e-mail: [email protected] phone: 719-535-9335 fax: 719-534-9050 I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 Fin slots Made easy by John Manfredo When I ﬁrst started cutting my own ﬁn slots, I used to use a hobby knife, which was quite tedious and didn't turn out that well. I know that there are more sophisticated methods and tools out there, but this is a good method to make things a little easier on you than the hobby knife method. Getting Started To begin, use a tube marking guide of some kind to mark the body tube for the ﬁn locations. Below, in photo 1, I used the one that is in "Model Rocket Design and Construction". It can be found at http://www. apogeerockets.com/design_book.asp. Next, take a piece of metal or an aluminum angle so that a line can be drawn out on the body tube along the same lines as of it. Photo 3 shows this screen. What you will be looking for is the location of the end of the ﬁn in inches and if the reference point for this is from the front or base of the owning part. Here we see that Photo 2 the location is .25" from the base of the owning part. Now go back to the body tube and, with a ruler, mark the tube on the lines that were made for the ﬁn locations. In my case, this mark will be .25" up from the base of the tube. This is where the aft end of the ﬁn will sit. We will call this position 1. Photo 3 As seen in photo 4, go ahead and draw a line from this point forward, longer than the length of the root length of the ﬁn (this is the edge of the ﬁn that goes against the body tube). What's the Point? The next thing we need to ﬁgure out is how long the root edge is. To ﬁnd this out, it will totally depend upon whether your ﬁns are simple trapezoidal/elliptical ﬁns or a custom free-form ﬁn set. Mine is a free-form set; continued on page 4 Photo 1 you have made already. This is shown in photo 2. Getting the Right Measurements We will be using Rocksim computer software to perform the next few steps. This will really come in handy! This program is an investment that will save you time, money, and frustration in no time ﬂat! To begin, go into Rocksim and ﬁnd your design ﬁle. Open up the ﬁn component in order to view the details Photo 4 About this Newsletter You can subscribe “FREE” to receive this e-zine 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. A P O G E E Page 2 R O C K E T S I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 First Annual Apogee Components’ Rocket Photo Contest Apogee is pleased to announce its ﬁrst annual rocket photo contest winners! It was felt that the First Place winning photo not only followed the rules of the contest, and was of good quality and composition, but more importantly depicted the heart behind our hobby; families together, passing down rocketry from one generation to the next. First Prize - Full Version of Rocksim 8.0 Ron and Hannah Cox This is a scratch/clone that Ron cobbled together based on pics of the shuttle express. He used RockSim to get his tube lengths just right to ﬁt the payload. Hannah wanted to launch some little toys of hers, which deploy on parachutes. The whole project was based on getting her involved in anything that wasn’t Barbies. Since then, she has been begging to go the National Air and Space Museum as well as Space Camp®. Ron thought it was a good picture of getting kids involved in something that wasn’t a video game or dolls. Second Prize - "Building Skill Level 2" CD Ian Cinnamon Our second place winner was chosen for many reasons. The composition is nice in that the boy launching the rocket is almost out of the picture, signifying the safe distance rule in rocketry. In addition, it is a nice liftoff photo. This rocket was built entirely from parts bought from Apogee. It even features the clear payload bay with a A P O G E E “Fun With Apogee Products!” RESULTS! camera in it! He used four BT-70 Apogee 18” tubes, four BT-70 Apogee tube couplers, 6 BT-50 apogee body tubes for ﬁns and a motor mount, one Apogee PNC-56A for the nose cone, one BT-70 apogee clear tube for the camera bay, 2 Apogee Centering Ring 24-56, two 1/4” Apogee launch lugs, and a lot of "Fix it" epoxy clay. He ﬁred it on an F39-6T reload and an E15-4W. Third Prize - "Building Skill Level 1" CD Len Johnson Finally, our third place winner depicted the teamwork in rocketry. Everyone in the picture has a role in the launch. One is holding the checklist, another is setting the rocket on the pad with another getting ready to back him up as he lets the model down. The last is steadying the chair. The St. Andrews TARC Team was caught in this scene setting up their model. They call it their “Iwo Jima“ shot before launch. This rocket was designed by St. Andrews Team members using the RockSim 8 software program. The rocket is powered by a cluster of two E9-6’s.The tubing is a BT-80 with 3/16” balsa ﬁns and custom designed rip-stop nylon chutes. R O C K E T S Page 3 I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 Photo 5 information about which is found in the "plot points" tab of the ﬁn screen. For standard ﬁns, the information for length is on the main screen. As you can see in photo 5, the root length for these ﬁns is 8". So now we can go back to the body tube and make a mark 8 " from position 1, going forward. This is Photo 8 were just in and check on the measurement. This one is 6.5" long, so now make the next mark that 6.5" rearward from position 3. This is seen in photo 9. Since there are so many little marks at this point, go ahead and make small arrows pointing to positions 2 and 3. This Photo 6 shown in the photo above and will be called position 2. Tab, Please! Next, we need to ﬁnd out how far the tab offset is. This is the distance that the tab begins from the forward end of the ﬁn, which was position 2. While in the ﬁn editing screen, click on the "TTW Fin Mount" tab. This will show you the information. Photo 7 shows that the tab Photo 7 offset for these ﬁns is 1". Now go back to the model and make a mark that 1" rearward from position 2. This is shown in photo 8. This gives us position 3 and the start of the tab; next we need the length of the tab. Go to the same ﬁn screen that you A P O G E E Page 4 Photo 9 will help distinguish them from the rest of the marks. You can see in photo 10 where I have done this. They don't have to be large, just enough to see. Mark my Words We've got the Photo 10 main measurments down, now we will actually make the marks and outlines for where the tabs will be cut out. Whatever the thickness of the ﬁns are, you will divide that in half. In my case, the ﬁns are 1/16" so that gives me 1/32". Take your favorite measuring device and make a small mark on each side of the lines for the ﬁn tabs continued on page 5 R O C K E T S I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 where the small arrows are. Again, for me, this will be 1/32" on either side of the ﬁn lines. I show this in photo 11. Do this for each end of the ﬁn tabs. Now we'll play "connect the dots" and draw lines from one end to the other, connecting the marks that were made. As shown above, you can see how handy the metal angle is turning out to be. Fun with Power Tools The Dremel® is Photo 11 your friend. Get one and use it. Seriously, I've talked before about this great tool. I got one a few years ago and use it for a lot of things! Take the Dremel® and insert a sanding disk attachment into it. You will want to use it on the high speed Photo 12 to cut the slots. This can be the tricky part; if you are not used to a Dremel®, especially on high speed, you should test it out on a scrap tube that's laying around. As shown in photo 13, the technique I use to cut the slots out is to grip the Dremel® ﬁrmly near the end closest to the attachment. Then I turn it on and butt my rounded index ﬁnger against the body tube. Work very slowly and carefully as a high speed Dremel® and working too quickly is a bad combination! The time you take to do this the right way will pay you dividends in the end with nicely Photo 13 A P O G E E Photo 14 cut ﬁn slots. As seen above, work your way to the end and then turn around and go back the other way until the slot is completely cut out. The Results In photo 15 you will see the results of my efforts. I really like the extra strength of having ﬁn tabs in my designs, especially if they are for E motors and above. If you would like to try some "scratch-building", we Photo 15 have plenty of supplies to help you out at http://www. apogeerockets.com/building_supplies.asp. I think you'll like this method! About the Author John Manfredo is the Education Coordinator and Newsletter Editor at Apogee Components. He’s a member of the Tripoli Rocketry Association and a certiﬁed Level 1 High-Power user. John hopes to achieve his Level 2 certiﬁcation next year. Married and the father of 6, he enjoys introducing his kids to this hobby that he is so passionate about. He has been building his own rockets on and off for the last 30 years. R O C K E T S Page 5 I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 For a limited time only, when you purchase the new Dynastar “Sky Torpedo” along with the “Building Skill Level 2 Model Rockets” CD ROM, you’ll receive a Generic Vacuuform Wrap to spice-up your latest creation at no extra cost! That’s a $7.50 value! You can’t go wrong and the crowd at the next launch will be envious of you as the “Sky Torpedo” punches and whirrs its way into the sky! You’ll get: 1 Dynastar Sky Torpedo ($41.95 value) 1 Building Skill Level 2 Model Rockets CD ROM ($21.15 value) 1 Generic Vacuuform Wrap with instructions ($7.50 value) For the low price of $ 63.10! ##00502 Act Quickly, this offer ends August 31, 2006 To order, visit: www.apogeerockets.com/sky-torpedo.asp RockSim: The Software That Lets You Design Amazing Rockets! RockSim is the leading software for designing rockets, and ﬁnding out how high they will ﬂy. Here is what rocketeers are saying about it: “After a lot of searching on the Net, Rocksim is the best rocketry simulation software I have seen. In terms of sophistication, ‘Rocksim’ is to ‘VCP’ as ‘VCP’ is to ‘cutting out pieces of cardboard’.” -- Brian Crosse Launch Success Begins with RockSim Dream It Design It n Simulate It n Build It n Fly It. n n Space Foundation certiﬁed as an excellent teaching aid. A P O G E E Page 6 www.RockSim.com For further information, call Apogee Components at: 719-535-9335. Mention this ad for a free CD-ROM of RockSim how-to videos. R O C K E T S I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 gle the rod. Picture 2 is my ﬁrst simulation where my launch rod is pointed straight up. The ﬂight goes fairly straight also. Picture 3 shows a launch when I angle the rod at +10˚ (with the wind); the model actually heads back into the wind. Lastly, in Picture 4, I run a sim with the rod at TIP OF THE FIN Rocksim can be used to decide what you should do when different wind conditions present themselves. This will help you avoid costly mistakes, aid you in achieving the highest ﬂights, or keep the rocket low depending upon your ﬂight desires. Picture 1 In Picture 1 you will notice that my model is quite overstable at 4.72 calibers (the distance from the center of gravity to the center of pressure). If there is no wind, this isn't a problem. But add wind into the mix and you have to decide how to an- Picture 2 Picture 3 -10˚ (into the wind). This makes the model weathercock pretty signiﬁcantly into the wind. Going to the simulation summary shows the ﬁnal results. I wanted to achieve the greatest altitude in this wind. As Picture 5 reveals, the best altitude was actually when I an- Picture 4 gled the rod +10˚ with the wind, achieving 1497 feet. I never would have guessed that would be the result. If you have a tip and I use it here, I'll send you a 58" Dynastar Ripstop Nylon Parachute. Write to me at [email protected]. Picture 5 QUESTION AND ANSWER CORNER We get asked here quite often why a Copperhead igniter looks so different from a 2-lead igniter and how you hook them up. The answer is shown below and to the right. The "1 lead copperhead" is actually 2 copper foils with a very thin insulator in-between them. To hook a Copperhead up to standard 2 clip ignition systems, simply follow the picture on the right. Stick a small piece of masking-type tape on either side of the lead and then hook your clips on. That way, current only gets to one side of each of the 2 thin foil leads. We currently stock Copperheads and First Fire Jr. igniters. These can both be found at http://www. apogeerockets.com/copperhead_igniter.asp and http:// www.apogeerockets.com/Aerotech_motors.asp#First_ ﬁre_anchor. A P O G E E R O C K E T S Page 7 I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 ® N A R NEWS Science Fair and R&D Projects As most research project ideas take a long time to conceive, and often require a lot of trial and error in experimentation, it is a good idea to encourage students to start thinking about their next science fair project months ahead of time. Students may also want to consider entering the model rocketry Research and Development competition at the NAR’s Annual Meet (NARAM) held each August. Dr. Joyce Guzik has written an article “R&D Advice”, originally published in the March/April 2004 issue of Sport Rocketry, to help competitors prepare for R&D events. Much of this advice also applies to science fair projects. An additional report, “Basic Statistics for R&D” by shuttle astronaut Dr. Jay Apt is also available, which has a short but detailed explanation of calculating a mean and standard deviation. For projects with repeated measurements, having enough trials for the conclusion to be statistically signiﬁcant is one of the ﬁrst things that the judges will look for when evaluating a project. These articles can be found at http://members.aol.com/GCGassaway/contest/R_and_D.htm. Careers: Exploring the Possibilities The New Mexico Network for Women in Science and Education has written a booklet aimed at middleschool and high-school students to encourage them to consider careers in science. The articles in this book are all authored by women scientists, which are designed especially to encourage girls to consider technical careers. The booklet also has articles on the importance of taking mathematics classes, ﬁnancing a college education, ﬁnding a mentor, dealing with stress, being assertive, and getting a summer job. The booklet can be found at http://biology.unm.edu/Potter/Careers/HTML/ C00TOC.html. A P O G E E Page 8 Educator Grant - $250 for Rockets The Air Force Association (AFA) is offering Educator Grants of up to $250 per academic year to elementary, middle and secondary school instructors for aerospace education activities. Funds may be used for anything aerospace related, from purchasing textbooks, videotapes, DVDs, model rockets, and radio controlled airplanes, to going on ﬁeld trips to aviation museums, military bases or local airports. The Educator Grant provides teachers with the opportunity to ﬁnd creative ways to introduce aerospace related activities into their classrooms. Applications are accepted from August 1 to November 15. For more information, go to http://www. afa.org/aef/aid/grants.asp: 3... 2... 1... Liftoff! Educator Guide This educator guide introduces children to the International Space Station (ISS), the most complex international scientiﬁc endeavor in history. Activities focus on the purpose and construction of the ISS, the history of rockets, and the role of rockets in space station assembly. Data collection, observation, exploration, prediction, interpretation, problem solving, and language skills are emphasized. (NASA) http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype//3-2-1.Liftoff.html: Reprinted with permission from NAR Education Chairman, Vince Huegele 2006 Get The Best Prices On Nylon Parachutes http://www.dynastar-rockets.com/Parachutes.html R O C K E T S I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 Page 1 of 1 If you want to build REALLYbig rockets try these two great books from Apogee Space Books www.apogeebooks.com 905 637 5737 "Apogee Books" is not afﬁliated with Apogee Components. But they do sell some nifty space books, and we do recommend them. A P O G E E R O C K E T S Page 9 I S S U E 1 6 5 - A U G U S T 1 5 , 2 0 0 6 For this issue's website, I am going to feature one from my home state of Colorado. The chosen site is that of Mike Bennett at http://www.mbrocketry.com. One of the top features of this site for me (because I like seeing rockets launch) is the video section. There are many videos that he has taken at launches of Tripoli Colorado, Northern Colorado Rocketry, Balls '03 and '04, and LDRS 25 of this year, just to name a few. There are 50 videos from LDRS alone! In all seriousness, what I really ﬁnd useful about this website is that Mike has a lot of educational information. There are sections that explain about the dif- ferent aspects of this hobby. Examples of these would be the different parts of a rocket and the different types of propulsion, including exploded views of the motors so that they are easier to understand (see opposite DEFINING MOMENTS Rear ejection or deployment is a type of recovery method in which the parachute exits out the back end of the rocket. It is useful as a drag reduction technique, eliminating the small gap at the base of the nose cone. Rear ejection pops the engine and recovery device out the back end of the rocket. This permits the gap between the nose and body tube to be ﬁlled and sanded smooth. The reason that I mention this is because one of the reasons that a modeler might want to change to rear ejection is that they may be trying for a rocket that is as aerodynamic as possible. If the streamer is being ejected out the back, the need for a nose cone that comes off of the model is gone. Most of the time this gap is insigniﬁcant, but to achieve optimum performance, this should be eliminated so that the ﬁnish will be more A P O G E E side). Safety issues, as well as recovery and computer software are talked about and have links including Rocksim, of course! You will also see that he likes "paying forward" to the younger generation. Pictured at the left is Mike (in the backright) with a friend and a group of boy scouts with Mike's "Sponge Bob" rocket. In addition, he has his Rocksim ﬁles pictured and available for download. I appreciate that in the "links" section there is a link for Apogee Components. It makes me feel good when we can be a help to anyone in the rocketry community! Great job with the site, Mike! If you have come across a site you would like me to feature, please email me at johnm@apogeerockets. com. aerodynamic. This will give the rocket a much smoother recovery. Parachute recovery is also possible with this method. One of Apogee's models that has rear ejection and helicopter-type recovery is the Texas Twister, found at http://www.apogeerockets.com/texas_twister.asp. �� Rear Ejection Illustration from Model Rocket Design and Construction www.apogeerockets.com R O C K E T S Page 10