I.Summary of Preliminary Design Report

  • School Name:Statesville Christian School
  • Mailing Address:Statesville Christian School

1210 Museum Road, Statesville, NC 28625

  • Mentors:Dr. P. Douglas Knight, Jr.

Project Supervisor

Physics Professor at Mitchell Community College

Mark Ford

Electronics Supervisor

Electrical Engineer at Thorlo Corporation

Launch Vehicle Summary:

Statesville Christian’s rocket will consist of 3 inch fiberglass tubing and will be approximately 72 inches long. The team will be using a Cesaroni K-1440 as the main thrust motor and possibly an Aerotech G-12 or Ellis Mountain G-33 as the reverse Thrust motor. The recovery system will be drogueless dual deployment with a Loki ARTS II altimeter and 72 inch parachute as the main.

  • Payload Summary:

The scientific payload for our rocket consists of a reverse thrust motor, of G or F impulse, in the nose cone of the rocket that will fire as the rocket travels transonic. We will measure the change in pressure along the outer body of the rocket through the use of four pressure sensors to determine if the hot gases from the reverse thrust motor reduce the shock wave seen as the rocket travels transonic.

II.Changes made since Proposal

The rocket and scientific payload that Team Statesville designed for the proposal has changed little since its initial design. The rocket will still consist of 3 inch fiberglass tubing but will be shortened to a length of approximately 72 inches and a maximum mass of approximately 10 lbs. We have decided to use a Cesaroni K1440 motor due to its quick time till full pressure and simplicity in use. Flying on a K-1440, the rocket will now reach an approximate altitude of 8500 feet and a velocity of Mach 1.3. The reverse thrust motor’s effect on the altitude and velocity is negligible.

The electronics payload as stipulated in the initial proposal has not changed. We have narrowed our search for a reverse thrust motor to either an Aerotech R/C 32mm G motor or an Ellis Mountain G. The fallback plan is to use the Apogee F10 like last year if necessary.

We are still on schedule with the milestones presented in the initial proposal and have not seen a reason so far to change the costs estimates for our rocket. The outreach plan has also not changed since the proposal.

III.Vehicle Criteria
  1. Selection, Design, and Verification of Launch Vehicle
  2. Mission Statement:

The Statesville Christian rocket team will successfully launch a rocket to transonic speeds and successfully recover the rocket and data to determine if the effect of Mach is reduced when traveling through a cloud of hot gas.

  1. Requirements and Mission Success Criteria:

The main requirement is the construction of a rocket that will reach apogee close to one mile and travel faster than Mach 1.0 with recovery as specified. Secondary requirements include ensuring the reverse thrust motor is aligned along the axis of the rocket, selecting a reverse thrust motor with no ejection charge, and ensuring the electronics can withstand the expected high “g” flight. For the mission to be a success, we must meet our requirements and be able to analyze our data to determine if Mach effects were reduced using our reverse thrust method.

  1. Major Milestone Schedule:

This is in section V (Activity Plan) section of this review paper

  1. System Level Design:

The rocket is three inches in diameter using fiberglass tubing along the body for strength. The motor mount is a 54 mm inside diameter with a Slimline Retainer used for negative retention. Four centering rings will be used for the motor mount. Fins will be of an isosceles trapezoid design similar to that of a Nike Smoke and will be constructed from G10 fiberglass. This design is for reduction of drag at high speeds. Fins will feature thru-the-wall construction with fiberglass fillets for the fins inside and outside of the rocket body. The nose cone will be a fiberglass boat tail sized to fit the body tube and reverse thrust motor. This should be much stronger than last year’s nose cone and provide high strength to secure the reverse thrust motor. Two ARTS II altimeters will be used for the safe recovery of the rocket. The primary altimeter will ignite a charge at apogee and the redundant altimeter at apogee +1 second. The primary altimeter will ignite the second charge at 1000 feet and the redundant altimeter at 800 feet. The motor will also provide an ejection charge near apogee. The dual deployment recovery will be drogueless at apogee and use a 72 inch parachute as the main with 15 foot long. Kevlar shock cords. The rocket will use launch rails for strength as the rocket leaves the launch pad. The altimeter payload section will be based on a LOC Precision payload bay design. Shear pins will be used to keep the rocket together through Mach and will be slightly larger this year to prevent drag separation. A Rocksim drawing of the rocket is shown below.

  1. Verification Plan:

We have designed a half scale model that will fly on a G80 or G77 to test the stability of the design and the reverse thrust motor mounting and firing technique. A Rocksim 2-D drawing is shown below. We plan to fly this rocket by the end of December. The full-scale rocket will be constructed in January through February with plans to fly in March to test for stability and acquire baseline data for a flight going through Mach without the effects of the reverse thrust motor. We are currently on schedule with our verification plan

  1. Risks and Testing Plans to reduce Risk

There are many risks to this rocket failing. Based on last year’s experience, the main issues are preventing drag-separation, electronic payload recovery and allowing time to complete the project.

The major failure mode last year was the drag separation coming out of Mach due to shear pin failure. We plan on using larger shear pins this year and also plan to watch our fit and finish at the coupler/body tube interface to make sure that there is no gap to possibly break the pins when the rocket first leaves the launch pad.

  1. Recovery Subsystem

The recovery system will involve two Loki ARTS altimeters for a dual deployment drogue less recovery. Details for this technique are in the system design section of the rocket.

  1. Mission Performance Predictions

The predictions for the flight of the rocket are 8500 feet of altitude, Mach 1.25 to 1.30 for maximum velocity, approximately 40 g’s of acceleration off the launch pad and a rocket with a mass of approximately 10 lbs. This is within the bounds to meet our scientific payload objective.

  1. Payload Integration

The team’s project requires that wires run from the top of the rocket to the bottom of the rocket to allow for the data sensors as well as a connection to the launch system. Team Statesville plans on running small tubing along the inside length of the rocket to provide a place for the wires.

  1. Launch Operation Procedures

Because of team Statesville’s project, two launch systems must be used. One to control the main thrust motor, and another to ignite the reverse thrust motor. The two are on separate ignition systems in case the reverse thrust motor does not ignite.

Outline for final assembly and launch procedures-

First, the team will prepare the recovery system. Dr. Knight will then make the ejection charges. Next the altimeters will be installed in the payload altimeter bay. Once in place, the ejection charges will be placed in the rocket and attached to the altimeters. Then the parachute will be loaded into the rocket.

Secondly, the motor will be prepared. Dr. Knight will insert the Cesaroni into its casing. The instructions will be followed step by step and then the closures will be tightened. It will then by friction fit into the rocket. After complete, the slimline retainer will be will be attached to the motor mount, providing negative retention on the motor. Next the reverse thrust motor will be inserted into the nose of the rocket.

Next, The igniters will be installed. Dr. Knight will install the igniters, following all the manufactures instructions.

Fourthly, the rocket will be set up on the launch rail. When the rocket is in place, the altimeters will be turned on. Next, the reverse thrust motor will be attached to the launch system. Once complete, the burn sensor will be placed across the top of the rocket. The main thrust motor will then be attached to the launch system and the continuity will then be tested.

When everything is complete, a countdown will commence. At T-2 seconds, the launch button for the reverse thrust motor will be pressed and the reverse thrust motor will ignite. At T-0 seconds the main launch button will be pressed and the rocket will fire assuming the reverse thrust motor ignites and the fail-safe works as expected.

  1. Safety and Environment (Vehicle)

The safety of all participants working on the project is of vital importance and will be the first priority of this team. During all the steps in this process, including the construction, testing and launching of rockets, all team members shall abide by the safety procedures set down by the NAR and TRA. All team members shall abide by posted safety guidelines during the construction and testing of the rocket as well as the testing of all its components. Each member of the team shall receive guidelines for the usage of materials that may be harmful if used improperly. A copy of these guidelines is included in the appendix. (See Appendix A, MSDS) Immediately preceding any meeting in which any construction or testing shall occur, the team shall be briefed by the safety officer, Philip Christiansen, on the proper and/or safe use of the necessary equipment.

The purpose of the safety officer is to make sure that all proper safety procedures are followed correctly, during construction of the rocket and in the testing and launching of the rocket. The safety officer for this project is Phillip Christianson. The safety officer will provide information to the other members of the team on how to properly utilize the available equipment to avoid mishap. After providing the information, the safety officer and Dr. Knight, the adult supervisor, will administer a test to the members of the team concerning safety issues. Before a team member can participate in construction, testing, and launching of the rocket, a perfect score must be achieved on this test. It is also the job of the safety officer to brief the team on the safety codes of the NAR and TRA along with any other safety issues that arise. This is vitally important as it ensures the safety of all involved in the launch. Dr. Knight and Mark Ford will oversee the safety officer in the performance of his duties and also be responsible for safety precautions during the construction, testing, and launching of the rocket.

Dr. Doug Knight will be the NAR/TRA mentor. He is affiliated with the local NAR/TRA chapter (Rocketry of the Central Carolinas, ROCC) and the South Carolina NAR/TRA chapter (Tripoli South Carolina, ICBM) and is currently Level 2 certified high power. He is also working on his Level 3 certification with TRA.

The area designated for the use of the team is the high school chemistry lab. All materials will be stored in conditions according to the directions issued by the manufacturer. All power tools will be unplugged when not in use, and when the group is not using the equipment, it will be stored safely so that others who may use the space shall not injure themselves.

Scale models will be flown with G or H impulse level or lower and may require a Low Explosive Users Permit (LEUP) for handling. Dr. Knight is Level 2 TRA certified and has a LEUP and will handle the scale model motor and other high power motors at the rocket launch sites. Scale models will be launched at the Midland, NC field of Rocketry of the Central Carolinas (ROCC) or at the Orangeburg, SC field of Tripoli, SC. Both clubs apply and receive a FAA waiver during their launches and the team will easily comply with their altitude requirements. Dr. Knight and Mr. Ford will oversee all scale model launches and the Range Safety Officer (RSO) must consider the rocket flight worthy before it is launched. The launch will be conducted by the RSO and Launch Control Officer (LCO) at the launch site for flying the rocket. Launch safety guidelines will be followed which ensures compliance with NAR safety requirements. Those certified to handle black powder and high power rocketry motors will be the only persons to handle any hazardous materials. Both local prefects are in compliance with local environmental laws and regulations and have never been cited for a violation.

General Safety Procedures:

  • At no point shall a team member be working alone. At least two people are required for any work, whether it is constructions or launching, that occurs.
  • Team members will wear safety goggles at all times during the construction and launching of the rocket.
  • Protective gloves shall be worn while using cutting tools.
  • Earplugs shall be utilized during the operation of loud equipment.
  • A mask shall be used if there is noticeable or expected dust in the air.
  • The work are shall be ventilated when epoxy or cyanoacrylate is used.
  • Gloves shall be worn when any more than a small amount of epoxy or cyanoacrylate is used. While curing, all flammable materials shall be kept away from the epoxy.
  • During launch prep, electronic devices will have switches to prevent accidental firing of the ejection charges and the firing of the reverse motor. Avionics will be armed only after approval from the safety officer and Dr. Knight.
  • Dr. Knight will handle all black powder and ejection charge preparation.
  • Material Safety Data Sheets (MSDS) are included in the Appendix for the solid motor propellant, igniters, black powder, West Systems Epoxy, and cyanoacrylate and will be given to each team member.

Safety

(Continued)

General safety procedures include the following (continued):

Tools / Risk / Avoidance Method
Jig/Circular Saw with Blade / Cut/Abrasion / Proper training, work gloves, goggles
Hand drill with bit / Cut/Puncture / Proper training, work gloves, goggles
Dremel with Accessories / Cut/Puncture/Abrasion / Proper training, work gloves, goggles
Screwdriver/Pliers/hand tools / Abrasion/Puncture / Proper training, work gloves, goggles
Soldering Iron / Burn / Proper training, work gloves, goggles
Knives/Blades/Scissors / Cut/Puncture / Proper training, work gloves, goggles
Electric Matches / Burn / Lockout/tagout of electronics, follow safety codes
Epoxy/Cyanoacylate / Burn/Fumes / Proper ventilation, latex gloves, watch flammables

Possible safety risks and methods to reduce risk for a successful launch of the rocket include:

Possible Risks / Method(s) to Reduce Risk
Rocket Motor CATO on launch pad or in flight / Rocket Motors will only be handled by Dr. Knight
Premature ignition of the igniter / Igniters will be installed at the launch pad and shorted until needed for launch
Ejection Charge Failure, rocket comes in ballistic / Dr. Knight will handle all ejection charges and rockets fired only at NAR/TRA sanctioned events. Altimeters and charges will be ground tested before flight
Rocket Shreds during boost, especially with velocities around Mach 1 / Fiberglass materials are used in the construction of the rocket along with high-grade epoxy. Fit and finish of rocket will be a priority. Larger shear pins will be used this year.
Rocket becomes unstable during flight / Rocket will be launched under NAR/TRA guidelines for safe distance during launch. Payload mass will be tested to be static by drop tests. Larger fins will be used to increase the static margin
IV.Payload Criteria
  1. Selection, Design, and Verification of Payload Experiment

Our scientific payload design has not changed from the initial proposal; except for reducing the reverse thrust motor of G-12 impulse. Since the rocket will only be transonic for a few seconds, it is very important that we collect enough data within this time to detect any possible reduction in pressure from the hot gas surrounding the rocket. The XBee Pro module and the Loki ARTS II altimeters can easily sample fast enough (minimum 100 Hz) to detect the changes in pressure we are hoping to see. Last year’s electronic design met our goals and with the increase in sensors to four, this should enhance our abilities to meet the requirements.