Little Dog Dual Deploy

Transcription

1 Little Dog Dual Deploy John Wilke & Paul Fechtmeister September 2010 All dimensions are in inches unless specified Construction Notes: Other items you will need: One set of epoxy Motor One sheet of 120 wet Igniters & Electric sand sandpaper Matches Ruler & Pencil 9V battery X-Acto knife Altimeter Popsicle Sticks for Epoxy Small Containers for mixing Long Wooden Stick Masking tape Mask if sanding fiberglass dry Fumehood Airframe Tube 16.0 bulkhead a.k.a. bulkplate Body Tube 25 "Ogive-cone" for 54mm tubing (fiberglass) Coupler 6.0 bulkhead a.k.a. bulkplate Parachute and recovery harness compartment. Altimeter compartment (a.k.a. coupler) Motor Tube 1. always "dry fit" parts - you can't overdo that it will help make your building a success. Also, it is a good idea to have some rubbing alcohol ("IPA", or isopropyl alchohol) handy when using epoxy this cleans up the epoxy quite well. Latex or vinyl gloves are great to have, too! Epoxy can be messy. Finally, exercise caution when using epoxy - if it gets into clothes or carpets, it will not come out after it has dried! Now, let's start construction Wash all tubes, inside and out - dry with paper towels and a broomstick 3. "Wet" sand rough edges off nosecone seam, leading and trailing edges of fin. Sand ANYWHERE epoxy will be used. Don't forget "fillet" area on fins, area where rings will be glued on motor tube and inside airframe, as well as along the fin slots. Also sand one face of each of the 4 bulkheads. ALWAYS WET SAND - I suggest 120grit under a hose, out in the lawn or in a deep laundry sink. Wear a mask if dry sanding. 4. Using a door frame or a piece of angle iron, make a long mark down the longer piece of airframe. It is best if this mark is lined up so it is between two fin slots. 5. WARNING - DO NOT COMPLETE THIS STEP until you are absolutely sure how the shock cord is going to be attached to the motor mount. Also the bottom launch rail should be attached before attempting this step. Epoxy centering rings to the motor tube, making sure they are aligned perpendicular to the motor tube. It may be helpful to wrap a piece of paper around the motor mount, and draw a line around the tube to help you align the rings. Put them about 1/8" from the lower end and 3/8" below the upper end. TRY NOT TO GET EXCESS EPOXY ON THE MOTOR TUBE. Allow epoxy to dry overnight. 6. Apply a light bead of epoxy fillets to the top and bottom of the rings - again, trying not to get epoxy either on the outer edge of the ring, or onto the motor tube itself. The fillets should be tight against the rings. Also, make sure you don t get any expoxy INSIDE the motor tube. 7. Using a long stick, dab a bit of epoxy on the inside of the rocket just above the slots. Slide the motor mount with the rings into the rocket. Just before the lower ring enters the rocket, dabble another small amount of epoxy around the inside of the airframe down near the bottom on the rocket. Finish sliding the motor and rings into the rocket, allowing it to dry in an upright position. The motor tube should be flush with the end of the airframe. 8. Dry fit the fins, making sure they still fit the slots (sometimes some epoxy from the prior step gets in the way!) When satisfied with the fit, put a fine bead of epoxy on the root edge of the fins. Slide them into the slots until they firmly contact the motor tube. Use the supplied fin jig to get your fins on straight. 9. After the fins are dry, apply "fillets" on each side of the fins. Do two fillets, allow to dry, rotate the rocket 120 degrees, do two more, allow to dry, and rotate for the final set of fillets. NOTE that you should have the fillets before proceeding to the next set of fillets. 10. Next, epoxy the larger and smaller bulkplates together, face to face. MAKE SURE THEY ARE CONCENTRIC - this can be done with a tight-fitting bolt, two washers, and a wingnut. Make sure the faces you glue together are all sanded. Make sure you remove any "burrs" or rough spots so the faces fit snug to each other. MOTOR SECTION CONSTRUCTION NOTES 1. All joints secured with Epoxy Rail Guide thick centering ring fin can NOTE: Motor section will accommodate Cessaroni Pro-38 case. (G or H motor). External Fin Dimensions thick centering ring Rail Guide dogsrocketry.com 2010 All Rights Reserved Motor Retainer

2 HL Rockets Little Dog Dual Deploy A rocket experiment. I ask you to divide your class in to teams of two. That is two persons per team. Each team will be provided a rocket kit from 3dogsrocketry.com. ( You will assemble the rocket during EHS time, at home and some class time will be devoted to the project also. Each student will be responsible for writing his or her own lab report documenting the assembly, launch procedure, the launch, and the recovery stage. Each report will have a hypothesis of the height of which your rocket will reach. Rocksim software is available in the lab and also for a free 30-day trial from apogee.com. Report will have: hypothesis, diagrams or photos, procedure (including safety procedures), data from the launch, analysis (calculations), escape velocity calculations, and a conclusion.

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4 Little Dog Project Timeline * project starts -- students informed of requirements and deadlines. Rocksim mockup due -- rocket parts washed and sanded NCR Oktoberfest project completion 9/13 9/17 Oct. 9th * more detail about deadlines found on the following page

5 9-13 Students are informed of project and deadlines. Students get kit on this day, project rubric, and information about rocksim and the Little Dog Dual Deploy Spec sheet. Also a demonstration of a dual deploy rocket. White Out - a Public Missiles AMRAAM 4 Dual Deploy rocket Rocksim workup of Little Dog Dual Deploy Due. If possible the flight of the rocket has been simulated and a stablity analysis has been done. Rocket has been washed to remove fiberglass dust, and parts have been wet sanded that are going to be receiving epoxy or paint. (i.e. the motor tube for the centering rings and the fins, the nose cone seam and the cone itself is roughed up if it is going to recieve paint, altimeter bay disks have been roughed up according to instructions, fins have their leading and trailing edges lightly sanded to remove edges, do not sand the other edges, the root of the fin is sanded 2 or 3 cm above the attachment point in order to encourage better adhesion of the epoxy once the fillet is applied, line is drawn down side of the rocket getting ready for attachment of the launch rail. Instructions on page 1 are complete through step four. Note: No Epoxy is to be applied yet! (20pts) TBD...