Reference / Paper · 2007
Peak of Flight #182: RockSim Technique - How To Put A Payload Bay Inside A Nose Cone
Apogee Components' Peak of Flight newsletter, issue 182 (2007-04-24).
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- apogee-components
- model-rocketry
Reference / Paper · 2007
Apogee Components' Peak of Flight newsletter, issue 182 (2007-04-24).
Apogee Components' Peak of Flight newsletter, issue 182 (2007-04-24).
I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 INSIDE: • Nosecone Payloads in RockSim • Defining Moments: Adapter vs. Centering Ring • Web Site Worth Visiting • Tip of the Fin: How To Make Your Life Easier With The "Part Tree" In RockSim 3355 Fillmore Ridge Hts Colorado Springs, Colorado 80907-9024 USA www.ApogeeRockets.com e-mail: [email protected] phone: 719-535-9335 fax: 719-534-9050 I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 Designing a Nosecone Payload Bay in RockSim Highlight the 29mm tube and then click on "ok." by John Manfredo How to design a payload bay using Rocksim for a rocket with little space Sometimes when designing a rocket, it is nice to have a payload bay. Unfortunately, due to the design, there may not be room for the standard payload bay in the model. The payload bay is usually located beneath the nose cone and above the main body tube. An example of this is the Dynastar Rising Star rocket (http://www. apogeerockets.com/rising_star.asp). But when the rocket is short enough that there is no room for this, or the main payload tube will be full, then you can make another payload tube in the nose cone. I won't be covering how to physically make this kind of setup, but will be concentrating on how to design it in RockSim. To start off, select the body tube and nosecone that you would like to use. For my choice I am using the BT-80 body tube and nose cone as seen in Picture 1. The next step is to highlight the nose cone on the components screen and then click on "inside tube" to add one of these to the design. As you can see in Picture 2, I decided to select an Apogee 29mm tube to use for the payload tube. I highlight the part and then click on the OK button. Picture 3 shows where the RockSim default location puts the tube. There are a few alterations that need to be made. continued on page 3 About this Newsletter 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. A P O G E E Page 2 Newsletter Staff Editor / Writer: John Manfredo Layout / Cover Artist: Dave Curtis Proofreader: Michelle Mason R O C K E T S I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 continued from page 2 Adjust the location unti the forward end of the payload tube is even with the inside edge of the nose cone Referring to Picture 3 again, you will see that the payload tube needs to be shifted aft a few inches, in addition to the length of the tube needing to be adjusted. To do this, select the tube and click on the part. The first adjustment we will make is that of the location of the forward end of the tube. Picture 4 shows where the proper location needs to be for this. Each side of the forward end should be touching the inside edge of the nosecone. The easiest way to accomplish these adjustments is to use the slider bar, seen here as well. When actually building the model this will position the payload tube on the centerline of the rocket. The next step to take is to shorten the tube, because at this point, it is too long for the actual design. As shown in Picture 5, the object is to shorten it until the aft end of the tube is not quite even with the base of the nosecone. In the actual mode you will want a way to grab onto the tube for easy removal. As said previously, the best way to do this in RockSim is to use the slider bar. You may have noticed that at this point the Centerof-gravity is behind the Center-of-Pressure, making for a very unstable design. I don't show the entire rocket, but if I did you would see that my design has no fins right now. This accounts for the Center-of-Pressure being so far forward. Shorten the tube length until the aft end protrudes slightly past the base of the shoulder of the nose cone. continued on page 4 A P O G E E R O C K E T S Page 3 I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 continued from page 3 Picture 6 illustrates the next part of the design process as I add on a bulkhead to the payload tube. In the real rocket this will seal the bay from any hot gasses that may make their way up to the nosecone. To do this I simply highlighted the payload tube and clicked on "bulkhead" to add the component. The default bulkhead database screen will pop up, but I just cancel out of this. Certain dimensions will already appear at this point for the bulkhead. One thing that will need to be altered is the thickness of the part. I am using 1/16" cardstock for the bulkhead, but enter whatever thickness of material you are using at the time. I convert 1/16" to .0625" for Rocksim and then move on to the location of the part. I chose to make it flush with the end of the payload tube. Picture 6 also shows this. That is all there is to it! The payload tube is all set in Rocksim for my simulations. I changed the view to 3D for you to see what it would look like. Picture 7 gives A P O G E E Page 4 Add a Bulkhead to the payload tube and change the "thickness" to .0625 you a side view of this design using different colors to accentuate the different pieces. Finally, on the next page I rotated the design in 3D in order to provide a different perspective on the model. As you can see, this provides a very useful place to put a device such as a locating transmitter or simple altimeter. R O C K E T S I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 continued from page 4 About the Author John Manfredo is a passsionate rocketeer, and formally the education coordinator for Apogee Components. He is Level 1 High-Power Certified and has been building and flying rockets since the early 1970’s. He enjoys passing his love of rocketry down to his kids. Question & Answer Question: "The instructions for the F37W reload kit list an ‘RMS-Plus delay element’ described as a ‘short solid part’. Either something has changed since they printed the instructions or this part is missing. I’d venture to guess that they combined the delay and ejection charge. I do not have the delay. The red ejection charge is open on one end with grains exposed. I have another ejection charge from a different kit and both ends are encased in red plastic." Answer: It is very common for different parts to slip inside of others from all the movement during transport. I remember when I first started using reloads, I thought I was missing the propellant grain until I found it inside of the liner tube. What I think happened is that the de- A P O G E E lay grain is stuck in the end of the red ejection charge holder. In other delay grain holders there are 2 ends encasing the charge as with the 29/40-120 reloads. One end of the cap goes on the nozzle and the other goes on the ejection charge well. The reload that you have is different in that aspect that the red cap is for the nozzle and the ejection charge is held in by the paper disk. This is the common way to hold an ejection charge in high power motors. If you take the delay grain out of the red cap I’d venture a guess that you will find the ejection charge covered by a smaller paper disk. Reloads are available for immediate shipping at: http://www.apogeerockets.com/Aerotech_Reload_Motors.asp. R O C K E T S Page 5 I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 A P O G E E Page 6 R O C K E T S I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 Apogee Components, Inc. is pleased to announce the second in a yearly grant program geared toward model rocketry education organizations! 4. One of the biggest things to keep in mind when composing your essay is “How is what I am planning unique?" The rules are simple: 1. Entrants must submit an essay to Apogee. There is no length requirement for the essay. 2. Any club, organization, or school program, is eligible for entry. This would include rocketry clubs or prefectures, 4H, scouts, etc. 3. The content and purpose of the essay is as follows: If we gave you $300.00, How would you use it to impact the rocketry community? How many people do you think it will reach? How many people will be involved in the organizing and running of the event? How big of an effect will it have on the rocketry community? • • • • There will be only one winner of the grant, which is $300.00 toward any order with Apogee Components. The deadline for entry is November 30, 2007. Make sure it is post-marked by November 30th! The grant winner will be anounced on January 1, 2008. What a great way to start off the new year! Or send to: 3355 Fillmore Ridge Heights Colorado Springs CO 80907 or: [email protected] http://www.apogeerockets.com/rocket_grant_money.asp A P O G E E R O C K E T S Page 7 I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 Get The Aspire 1/2 Off! Just buy an Apogee F10-8 and an E6-6 motor That is a savings of P/N: 00510 Price: $46.31 $8.79! To Purchase Go to: www.ApogeeRockets/April_Special.asp TIP OF THE FIN The tip for this issue is about how to make your life a lot easier with the "parts tree" in RockSim. So much of the time we see design files where there are many different tubes in the design. This would include anything from body tubes to motor mount tubes to payload tubes and so on. By the time you have that many tubes in the design it becomes very difficult to tell each one apart, and you wind up wasting much of your valuable time tryng to find the one part that you need to do some work on! The best tip I can give is to NAME your parts separately so that it is very easy to tell them apart. As seen in the picture on the right, it becomes immediately apparent which tube is which. This tip also applies to centering rings, mass objects and other parts. The more detail you go into makes it so much easier to trouble shoot problems that arise, and just simply make things easier so that A P O G E E Page 8 you can spend a lot more time building and flying the models that you design! If you have a tip to share, please send it to us at [email protected] R O C K E T S I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 DEFINING MOMENTS What is an Adapter Ring versus a Centering Ring? The short, thick-walled cylinders used to center one tube inside another are called adapter rings. Centering rings are similar to adapter rings, except they are flat. If the difference between the two tube diameters is greater than 12.7mm (1/2”), it is probably easier to make a flat disk centering ring than an adapter ring. A centering ring will also weigh less than an adapter ring, which will make your model lighter. A kit that uses an adapter ring is the Apogee Diamondback (at: http://www.apogeerockets.com/Diamondback.asp.) One of the many kits that use the disktype centering ring is the Dynastar Rip-Roar, which can be seen at: http://www.apogeerockets.com/Rip-Roar. asp. Try one of these beautifully-crafted kits today and be prepared to "wow" your friends at the field! Adapter Ring Disk-Type Centering Ring Tape Adapter Ring/Centering Ring Graphic from Model Rocket Design and Construction www.apogeerockets.com Web Site Worth Visiting Our website for this issue comes to us via reader Ray Sunderlin. The site is called Encyclopedia Astronautica and can be surfed at http://www.astronautix. com/index.html. If you are a space history "buff", then this site is for you! This is one of those websites that you could get lost in for days. If you have an interest in scale models, you will find a lot of information here as well. Some of the many areas to peruse include rockets, people, chronology, and spacecraft. I know you must be wondering about the rockets and spacecraft sections being redundant, but the difference is that rockets here are considered missiles and spacecraft are rockets like the Saturn V. Interesting facts are available under all these listings. There are even Space poems! Michael Collins' wife wrote this one prior to his launch to the Moon on Apollo 11: A P O G E E I could have sought by wit or wile Your bright dream to dim. And yet If I’d swayed you with a smile My reward would be regret. So, for once, you shall not hear Of the tears, unbidden, welling; Or the nighttime stabs of fear. These, this time, are not for telling. Take my silence, though intended; Fill it with the joy you feel. Take my courage, now pretended-You, my love, will make it real. There is so much to see, as I said before, that you could get lost for days on this site. Now, go enjoy being lost! R O C K E T S Page 9 I S S U E 1 8 2 - A p r i l 2 4 , 2 0 0 7 We Moved! We finally did it! After occupying it for 4 years, our old production and manufacturing building just got too tight. Boxes were stacked too high, and it was starting to interfere with processing your rocketry orders. A few months ago, we found a bigger building and started the process of getting it ready for its new task: "The World Headquarters of Apogee Components." We now have 6,000 square feet of space, with plenty of room to expand our product selection. Far Right: The construction of the additional offices to make room for future employees to handle your orders faster. Right: The great big warehouse that we use to hold all of the products we sell. Far Right: Michelle and Robbie trying to make sense of the warehouse shelving. Right: Carla, creating a wonderful mural to set the scene in the new office. Blue skies and calm wind - that's what we live for when launching rockets. Right: The outside of the new building. We have the whole thing to ourselves. 3355 Fillmore Ridge Heights Colorado Springs, CO 80907 A P O G E E Page 10 R O C K E T S