University of Idaho



Dr. John FoltzCollege of Agriculture and Life SciencesUniversity of IdahoPO Box 442336Moscow, Id 83844-2336 DATE \@ "MMMM d, yyyy" May 11, 2012RE: Idaho APPS Final Design ReportDear Dr. Foltz,Attached is the final design report for the Idaho APPS project.We have outlined the future work that will need to be done in order to comply with the requirements of the Health and Safety office. As discussed in the last meeting, a professional engineering or someone in the field of ballistics or explosives should inspect the cannon before it is used. This will also help determine if we have overlooked any safety risks. Appendix 2 shows the DFMEA we briefly discussed in the meeting. This outlines potential failures and could be used as a tool for whomever inspects the cannon.Appendix 4 shows the math model used to predict launch criteria. This can be used as a tool for learning at the corn maze. It is also discussed in the Math Model section of the report.Please feel free to contact me over the coming months if you have questions. As I said before, I’d be happy to help, but I may be unavailable at times. If that is the case, I will be sure to contact you once I am available again.Our team thanks you the opportunity to be involved in such a fun project. We all learned a lot and look forward to seeing how our project is accepted by users at the Clearwater Corn Maze this year.Sincerely,Kara PeerTeam leader, Idaho APPSpeer3026@vandals.uidaho.edu208-691-9105 (text or call)Idaho APPS Final Design Report(Advanced Pumpkin Propulsion System)Josh BoumaKara PeerRamzi SadeddinsaramaAndrew SchmohrShelby SmithSubmitted: DATE \@ "MMMM d, yyyy" May 11, 2012Executive SummaryIdaho APPS (Advances Pumpkin Propulsion System) is a team of seniors working together to build a pumpkin cannon for Dr. John Foltz, the Associate Dean of the College of Agriculture and Life Sciences. The cannon will be used as an additional attraction at the Clearwater Corn Maze held in Lewiston, Idaho each fall. The cannon will be used by the general public to shoot pumpkins that range from five to eight inches in diameter at a target approximately 150 yards away. The pumpkins will explode once they hit the plywood target and spectators will be able to check their aiming accuracy.The cannon is designed to use compressed air as its propellant. The cannon will be loaded from the open end of the barrel by a designated operator. The trigger mechanism is a level action butterfly valve. To increase recovery time between launches, the cannon will be rigged with one air tank and one accumulator tank. The cannon will also feature horizontal and vertical aiming capabilities to give the participant the full experience of shooting a cannon.Safety protocols are being implemented in the design to ensure both the participant and the employee overseeing the launch site are at no risk. A safety manual will accommodate the final product as well as detailed instructions on how to operate the cannon.Contents TOC \o "1-3" \h \z \u Background PAGEREF _Toc324498964 \h 1Problem Definition PAGEREF _Toc324498965 \h 1Client Needs PAGEREF _Toc324498966 \h 1Specifications PAGEREF _Toc324498967 \h 2Concepts Considered and Design Selection PAGEREF _Toc324498968 \h 2Propulsion System PAGEREF _Toc324498969 \h 2Rail Gun PAGEREF _Toc324498970 \h 2Compression Spring System PAGEREF _Toc324498971 \h 3Extension Spring System PAGEREF _Toc324498972 \h 3Compressed Air System PAGEREF _Toc324498973 \h 4Propulsion System Selection PAGEREF _Toc324498974 \h 5Aiming PAGEREF _Toc324498975 \h 5Health and Safety Criteria PAGEREF _Toc324498976 \h 6Math Model PAGEREF _Toc324498977 \h 6Prototype Testing PAGEREF _Toc324498978 \h 8Final Design PAGEREF _Toc324498979 \h 10Design Evaluation PAGEREF _Toc324498980 \h 10Budget PAGEREF _Toc324498981 \h 10Full Scale Test Results PAGEREF _Toc324498982 \h 11Future Work PAGEREF _Toc324498983 \h 11Appendices PAGEREF _Toc324498984 \h iAppendix 1.SolidWorks Drawings PAGEREF _Toc324498985 \h iAppendix 2.DFMEA PAGEREF _Toc324498986 \h iiAppendix 3.Launch Protocol and Procedure PAGEREF _Toc324498987 \h viAppendix 4.Math Model PAGEREF _Toc324498988 \h viiiBackgroundDr. John Foltz (Associate Dean of the College of Agriculture and Life Sciences) has funded a senior capstone design team to design and fabricate a pumpkin cannon to be used as an additional attraction to the Clearwater Corn Maze held each fall in Lewiston, ID. Idaho APPS (Advanced Pumpkin Propulsion System), the student design team, was formed to accomplish this task. Dr. Foltz would like to have the pumpkin cannon as an attraction at the corn maze for the general public to shoot pumpkins at a target for a small fee.Proposed cannon launch site2011 Clearwater Corn MazeBuilding pumpkin cannons and Pumpkin Chunkin’ contests are growing in popularity. Most pumpkin cannons are only used by the people who built them; however, this pumpkin cannon will be different in that the public will have an opportunity to shoot the pumpkin as well. Also, this cannon will not be designed for distance; rather it will be used for accuracy in hitting targets. In years to come, Dr. Foltz would like use this project as a spring board for a Pumpkin Chunkin’ contest that the Clearwater Corn Maze will host. Idaho APPS will design the first cannon as a trial run to judge interest in such contests.Problem DefinitionThe problem definition was the development and design of a pumpkin cannon for use at the Clearwater Corn Maze. Most pumpkin cannons are built by trial and error. As a Senior Capstone Design Project, this cannon will be built from an engineering standpoint. The Idaho APPS team expects to design and engineer this cannon using their combined knowledge from their engineering coursework.Client NeedsThe following client needs are listed below:Safety is top priorityProject a 5-8 inch diameter pumpkin 100 to 200 yardsAiming capability, with some sort of sight on the barrelMobile (on 2 or 3 wheels), with a hitch to be able to connect to a tractor or car for movingSufficient velocity to smash the pumpkin with an impressive explosionOperator and bystanders do not need to wear hearing protection Short or no recovery time for the system (1-3 minutes)Lowest construction cost possibleEstimated life of the product should be 5-8 years or longerAesthetically pleasingSpecificationsSpecifications were developed from the above client needs and are presented below in Table 1.Table 1 SpecificationsSpecificationsQualitativeQuantitativeSizeWheels to handle terrain8 inch diameter or largerSmall enough to store in extra shop/shed space6 ft by 15 ft footprintBarrel large enough for 8 inch diameter pumpkins8 inch inner diameter barrelSafetyUser friendlyNo age limitNo hearing protection neededLess than 125 dB when firingTamper proof overnightApply lock in under 1 minuteLaunch far enough to break pumpkin but short enough to see it breakRange 100 – 150 yardsFeatures“Coolness” Factor (aesthetics)At least 8 on a scale up to 10 by Dr. FoltzShort recovery time between launchesLess than 1 minuteLong design life5 to 8 years (40,000 uses)Horizontal Aiming15 degrees off center both directionsVertical Aiming75 degrees up from horizontalConcepts Considered and Design SelectionPropulsion SystemRail GunOne of the first ideas for propulsion was to use the concept a rail gun. A magnetic plate would be accelerated along the inside of the barrel by a series of electro-magnets pulling the plate towards the open end of the barrel. The pumpkin would sit on the magnetic plate and would be launched from the barrel with the plate came to rest at the end of the barrel. One advantage to this design is it would be very quiet to launch. However, the disadvantages are that it would require a lot of electricity and it would be expensive to build and pression Spring SystemThere were two ideas for spring propulsion systems. The first one was a compression spring system. REF _Ref311575524 \h REF _Ref324160340 \h Figure 1 below shows a sketch of the set up. There would be two (or more) springs connected to the back of the barrel and to a plate inside the barrel. A cable would be attached to the middle of the plate and exit through the back of the barrel where it would be attached to a cable winch. The pumpkin would rest against the plate inside the barrel. To launch the pumpkin, the cable winch would crank back the plate and compress the springs. Once the plate is far enough back, a catch would hold it in place and the cable would be released from the plate. A mechanical trigger would release the catch on the plate and the springs would decompress, pushing the plate and the pumpkin forward. When the springs reached their free length (fully decompressed length), the plate would stop and the pumpkin would be launched out the end of the barrel.Figure 1 Compression Spring SketchThe major advantage to this system is there would be no electricity required to launch the pumpkin. Since the launch site is at the corn maze, it may be difficult and expensive to get electricity to the cannon and a spring system would negate this inconvenience. Another advantage is the low cost. This system would not only be inexpensive to build, it would have little to no operating and maintenance costs. However, there are disadvantages as well. Mainly, as the springs decompress to their free length, they lose acceleration. This would cause the pumpkin to actually slow down as it reached the end of the barrel. If the springs were strong enough to give the pumpkin the initial velocity it needed before the springs were completely at their free length, this problem could be avoided. However, this would require a lot of prototyping and testing.Extension Spring SystemThe second spring system considered was similar to a slingshot. REF _Ref311625556 \h Figure 2 below shows a sketch of this system. This design would use multiple extension springs connected to the back of the barrel and to cables (shown in red) on either side. The cables would then each wrap around a pulley and attach to a basket in the middle of the barrel. The pumpkin would rest in the basket. To launch the pumpkin, the basket would be pulled back and hook on a catch outside the rear of the barrel. The springs inside would be stretched as the cable pulled them forward toward the pulleys. A trigger would release the catch and the springs would pull the cable back, launching the basket and pumpkin forward, and the pumpkin would be launched out the end of the barrel.Figure 2 Extension Spring SketchBy using extension springs and making them shorter with a higher spring constant, this would minimize the de-acceleration problem with the compression spring concept. It would still be an issue, but extension springs set up in this way have a more constant acceleration. This system still has the advantage of low cost as the other spring system did. However, there would still be a lot of prototyping and testing required for everything to work properly. Another disadvantage to both spring systems is they required more physical strength to launch and they take time. It could take longer than the required one minute to pull the pumpkin back into pressed Air SystemThe final concept considered was a compressed air system. This is how most existing pumpkin cannons are designed to launch pumpkins. REF _Ref311629074 \h Figure 3 below shows a sketch of this system. The compressed air system would have two air tanks on either side of the barrel. The tanks would be filled with an air compressor to the required air pressure. The tanks will be sized such that only one tank will be needed to launch a pumpkin. This way, there is a faster recovery time between launches. Each tank would have a ball valve to control the expulsion of the air from each tank separately. Inside the cannon would be a sabot for the pumpkin to rest against. The sabot would create enough of a seal to keep the barrel pressurized as the pumpkin is launched. To launch the pumpkin, a solenoid switch will actuate one ball valve, releasing the air in the tank quickly into the barrel. The air would then push the sabot along the barrel and launch the pumpkin. The compressor would turn on and begin filling the first tank while the second tank would be ready to go for another launch.Tank 2Tank 1Ball ValvesCompressor Figure 3 Compressed Air SketchOne of the main advantages to this system is the force behind the pumpkin coming from evenly distributed air pressure should increase consistency and accuracy. There would not be any de-acceleration problems like the spring systems experienced. Another advantage is that it would not require as much prototyping and testing. A disadvantage of this system is that it will be more expensive, both to build and to operate. There will need to be electricity available at the site in order to continuously run the air compressor, which will be an additional cost each year.Propulsion System SelectionA decision matrix was constructed to compare each propulsion system and rate them in different categories. REF _Ref311629925 \h Table 2 below shows the decision matrix with the final values. There were three categories chosen to rate each propulsion system: ease of use, cost, and ease of design/manufacturing. Each category was given a weight based on how important that category was to the overall design. Each propulsion system was rated on a scale of one to ten for each of the three categories, one being the lowest score and ten the highest. The ratings were chosen by all five group members, and then averaged to get the numbers in the table. Each number was then multiplied by the appropriate weight and totaled at the bottom of the column. The propulsion system with the highest score was the compressed air system and was the system selected to move forward with.Table 2 Decision MatrixItem WeightCompressed AirCompression SpringsExtension SpringsEase of Use508.86.27.6Cost30678Ease of Design/Manufacturing20866.1Total100780640742After prototype testing was completed and the full scale cannon went into production, there were some logistical issues with using two compressed air tanks. With the limited budget, it was difficult to safely mount two tanks to the frame. Also, as the horizontal and vertical aiming decisions came together, it was determined that the accumulator tank which would hold the air had to rise and lower with the cannon barrel. This would be very difficult with two barrels. It was decided that one accumulator tank would be used and an air compressor large enough to decrease the time to refill the accumulator should be purchased.AimingThe cannon is required to have vertical and horizontal aiming capabilities. There were a few ideas for the horizontal aiming, but all with the same basic concept. This concept was that the cannon had to swivel at its base. One idea was to mount the cannon to a frame shaped like football goal post. Then, the base of the goal post would go through an opening below it and sit on roller bearings. The roller bearings would allow the goal post to rotate side to side. This concept was upgrades when one of the team members found a swivel plate. The swivel plate had a plate on the top and bottom of some bearings and accomplished exactly what was intended by the design described above. There were a few concepts considered for vertical aiming. One idea was to have a rack and pinion attached to the base of the cannon. The rack would be attached to the base and the pinion would be attached to the bottom of the barrel. When the pinion gear is turned, it would move along the rack, raising or lowering the barrel. A similar concept for the vertical aiming was to use a scissor style jack. This would be attached to the barrel of the cannon about half way up the barrel. When the jack screw is turned, it would raise the barrel of the cannon. One problem with this system is the sleeve the jack is attached to the barrel with will have to shift slightly as the barrel is raised and lowered. The scissor jack would be the cheapest solution and therefore it was chosen for the vertical aiming. The final vertical aiming design included two posts anchored to the base of barrel that could be cranked up and down. A cradle connecting the two posts would support the barrel. The curvature of the cradle allows the cannon to slide as needed for horizontal aiming. The aiming system is illustrated in Appendix 2.Health and Safety CriteriaSince the cannon will be used by the general public, with the supervision of the client’s employees, the cannon needs to be easy to use and safe to operate. The Environmental Health and Safety office met with the team on numerous occasions to ensure their requirements were met. To make the cannon as safe as possible for the user, it is required that a designated operator be in charge of going through the launch procedure. The user is still responsible for triggering the system. A few key operations and safety guidelines are outlined below.The cannon and all its components should be inspected prior to each season according to the guidelines in the safety manual.The cannon is to be front loaded by a designated operator, not the user.To shoot the cannon, the operator must follow a few rules and guidelines. The launch protocol and procedure is provided in Appendix 3.The launch protocol can be dramatized to improve the theatrics, but all the steps of the procedure must be followed.While the corn maze is closed, the air compressor will be disconnected and all hose connections will be removed to prevent anyone from tampering with the cannon or using it unsupervised.Math ModelA math model was produced to mathematically determine what is going on during propulsion. This was used in conjunction with the prototype testing to get some ideas of how to size many of the components on the cannon. It was also used as a tool for predicting the exit velocity, the distance the projectile will go, and other flight parameters.In our design, the pumpkin is propelled by work done from the expansion compressed air in the storage tank under isentropic process. Isentropic processes assume constant entropy from the initiation until completion of the process.Work done by expanding compressed air= Initial energy of compressed air – Final energy of compressed air – Atmospheric W=P1*V1k*V1+As*Ls-k+1-k+1-P1*V1-k+1-Patm*As*LsP1: Initial pressure of compressed air, before opening the valve (Pa)V1: Initial volume of compressed air, volume of storage tank (m^3)As: cross sectional area of shooting barrel (m^2)Ls: Length of shooting barrelk: isentropic process constant, (1.4)Patm: Atmospheric pressure (101,325 Pa)Now, from work we can calculate the initial velocity of the pumpkin – the velocity at the end of the shooting barrel as soon as it exit’s.Work from compressed air = Kinetic Energyw = (m * v^2)/2v = SQRT (2*w/m)v = initial velocity of pumpkin (m/s)w: Work from compressed air (Joules)m: mass of pumpkin (kg)From the initial velocity of the pumpkin, we are able to use the projectile motion equations to predict the horizontal distance of travel for the pumpkin. The following equations consider the air drag, as it works against the motion of the pumpkin decreasing the distance of travel.For the horizontal travel,Sx: Horizontal distance (m)m: Pumpkin’s mass (kg)Vxo: Horizontal initial velocity (m/s) = v * cos (θ)Θ: Launching anglet: time of travel (s)k: Drag constant = pumpkin’s mass (kg)*gravitational acceleration (m^2/s) / terminal velocity (m/s)Terminal velocity = SQRT (2*pumpkin’s mass*g / Cd(drag coefficient)*air density*pumpkins area)For the vertical distance, Sy: Vertical distance (m)Vyo: Vertical initial velocity (m/s) = v * sin (θ)From the above equations, a spread sheet on excel is produced and different time increments are inserted in both equations, the horizontal distance is when the vertical distance goes to zero. Figure 4 Plot of flight path produced from math model.4581525114300Prototype TestingAfter the math model was constructed we began prototyping. We built two prototypes out of 2 inch schedule 40 PVC. Both prototypes had 2 foot long barrels and a ball valve acting as the trigger. The difference between the two prototypes was the accumulator lengths, one was made with a 1 foot accumulator the other had a 2 foot accumulator. This doubled the volume that the second accumulator had. The prototype shown here was the one with the shorter accumulator length. A golf ball was used as our projectile, this was useful because they are all the same size and weight. A foam sabot was placed behind the golf ball to prevent further pressure losses from air escaping around the projectile. To test the prototypes we found a park with a safe launch point to fire the projectile. We then tested both prototypes at two different pressures, 20 and 30 psi. After the accumulator was charged we held the launch angle at a constant 45 degrees and fired. The distances were measured using a measuring wheel and recorded for statistical analysis. Some factors that were out of our control and assumed as constant during testing includes, wind speed and direction, air temperatures, and the speed the valve was turned. These variables may have affected our data in. We shot each prototype 20 times at each pressure (20&30 psi).Figure SEQ Figure \* ARABIC 5 Graph of results from prototype testingTable SEQ Table \* ARABIC 3 Statistical analysis of results from prototype testingShort Accumulator (1ft)Long Accumulator (2ft)Pressure (psi)20302030Math modelPrediction (ft)107145144282Mean (ft)113.7151.25149.8286.15Median (ft)113.5152150286.5Std. Deviation 4.466.133.568.48Variance19.9137.5712.6971.92Final DesignThe final cannon was built with a schedule 80 PVC holding tank and fittings. The barrel itself is schedule 40 PVC due to supply limitations and the fact that it takes lower average pressures than the holding tank. It’s still rated for operating pressures over triple the pressure we use to launch pumpkins. The barrel is connected over the holding tank by two elbows and an 8 inch lockable flanged butterfly valve forming a C-shaped design as shown in the picture below.The cannon rests on a six wheeled base originally designed for a tractor pull competition. It is held on by a collar that connects to a rod allowing the cannon to swing up and down. The rod runs through a rear support shaped like a football goal post that is mounted on top of a steel turn-table. The turn-table bolts to the frame and allows horizontal sway for aiming. The front end of the cannon rests on another goal post style support that can be jacked up and down for vertical aiming and allows a certain safe degree of horizontal aiming. On the front of the base is a flip down wheeled trailer jack to allow the cannon to be rolled around a location.The system can be charged by any compressor, but the one included with the cannon has a regulator that allows the operator to set the pressure before attaching it to the holding tank and simply allowing the compressor to fill the holding tank to the right pressure. There is a quick connect attachment on the holding tank for charging the cannon. There is also a pressure relieve safety valve tapped into the holding tank at the standard 125 psi. Near the valve at the back end of the cannon a pressure gauge is mounted so the operator can always see if the system is charged and to what pressure it has been charged before actuating the valve.Design EvaluationBudget The final budget is shown in REF _Ref311648492 \h Table 3.Table 4 Preliminary BudgetItemCostBase and Wheels $ 594 Barrel – 10 “ SCH 80 PVC $ 600 Scissor Jack (vertical aiming) $ 50Steel Plate (horizontal aiming) $ 75Valves, Elbows, Wye $ 270Compressor$ 300Air Tanks$ 170Fasteners and Miscellaneous$ 200Subtotal$ 2,259Total$ 2,485* These items have yet to be purchased.The total budget fro this project was $2500, this amount was to include prototyping and all other project expenses. We wanted to keep the expenses of the project as low as possible that is why we chose the materials and procedures that we did. The total amount spent on prototyping was around $65, keeping the prototype cost low allowed us to have money for other aspects of the cannon design. The actual cannon cost $1400 for the parts that were needed, a large portion of this was spent on the air compressor that was needed to fill the accumulator tank. Things that still need to be considered in the budget are Kevlar sleeves for the accumulator and barrel. All future work should be able to be completed within the current budget.Full Scale Test ResultsAfter designing all the components of the cannon, a Design Failure Mode Effects and Analysis chart was developed to determine potential failure modes. The chart, show in Appendix 2, lists an item or part, then a possible failure mode. For example, the frame is a part and a failure mode would be bolts coming loose. Then it lists the effects of the failure. In this case, the cannon could fall apart. This is rated on a severity scale from one to ten where one has no effect and ten is hazardous and makes operation unsafe to the operator and involved non-compliance with government regulations. Then next column indicates the potential cause of the failure followed by an occurrence rating. This is again on a scale of one to ten where one is unlikely and ten is extremely likely. Following the occurrence rating is the current design controls. This column indicates what is currently being done to help minimize or eliminate the failure mentioned. The following column is a detection rating on a scale of one to ten. This indicates how likely the current design control is going to detect a failure. The column titled RPN multiplies the 3 rating numbers together to get an idea of how crucial the potential failure mode is. The final column shows a recommended action for preventing the failure. In most cases, reading the safety manual is the best way to prevent failure.Future WorkWith the cannon completely constructed and tested, the bulk of the future work for this project will be dedicated to licensing procedures and meeting special Health and Safety requirements. It takes a considerable amount of time to complete that process. This will require the project to be passed on to another team. The cannon can be used for demonstrations but in order to be used as an attraction at the Clearwater Corn Maze more safety requirements must be met. Certain safety protocols will be examined closely. The University of Idaho Environmental Health and Safety office will need to sign off the final design. They will also help ensure an adequate safety and operation manual has been written to accompany the cannon when it is passed on to the client.The most important current change that needs to be completed is the addition of a Kevlar sleeve around all the PVC components. While they are all rated well above operating pressures and have burst pressures 10 to 20 times our maximum operating pressure, the possibility of them bursting must be accounted for. A Kevlar sleeve would be relatively cheap and easy to install while adding both strength by reinforcing the PVC as well as a layer that would contain any fragments if there ever was a burst. It would allow the pressure to escape, but not the potentially dangerous shrapnel.In addition, the cannon still needs to have a sight installed. A rear peep hole should be installed through which to look at a front crosshair sight mounted to the forward vertical barrel support. This would allow the operator to see directionally where they will be shooting. The system will need to be sighted in and correlated for different pressures, angles, and pumpkin weights.The horizontal aiming is currently done by simply pushing the barrel one way or another at the front support. A long leverage arm should be attached to the top swivel plate at the rear support so that the operator can more easily get the force needed to rotate the cannon from the back. This would enable quicker horizontal aiming adjustment and eliminate having to move from the back of the cannonIn order to ensure the cannon complies with all health and safety regulations, the apparatus must be inspected by a professional engineer or someone with adequate knowledge in the field of ballistics or explosives. It is suggested that an inspection occurs at the beginning of each season before the accumulator tank is charged for the first time. It is also suggested that after an initial inspection as soon as the cannon is complete, a safety manual should be written. Anyone who is to operate the cannon should be familiar with the safety manual in order to remediate any problems that could arise during operation.AppendicesSolidWorks DrawingsDFMEADESIGN FAILURE MODE AND EFFECT ANALYSIS(DFMEA)ProjectIdaho APPSRevision Date9-May-12Year2011-2012Revision Number4Team MembersShelby, Ramzi, Josh, Andrew, KaraITEM AND FUNCTIONPOTENTIAL FAILURE MODE(S)POTENTIAL EFFECT(S) OF FAILURESEVPOTENTIAL CAUSE(S) OF FAILUREOCCURCURRENT DESIGN CONTROLSDETECTRPNRECOMMENDED ACTIONSBaseWheelsaxle breakscannot roll6rough terrain1check terrain before installing wheels16??Hitchdetachingcannot tow6excess force1material type and attachment to base sufficient16??framebolts come loosecannon visibly falls apart8cyclic loading/ vibration5tighten all bolts before operation140Read safety manual frequently, especially before each season?framebolts come loosecannon gets loose from frame and goes un noticed10cyclic loading/ vibration5tighten all bolts before operation150Read safety manual frequently, especially before each season?framebreakingbarrel falls through 9excess force2frame made from steel118Read safety manual frequently, especially before each seasonBarrelSabotdegradationfailure to launch8moisture, excess force3material type124??sabotstuck in barrelfailure to launch8improper loading1use plunger to load216Read safety manual frequently, especially before each season?Barrelburstingno accumulator tank or barrel10defects in barrel1Kevlar sheath to prevent flying shrapnel220Read safety manual frequently, especially before each season?Barrelburstingharm to operator/ audience10defects in barrel1Kevlar sheath to prevent flying shrapnel220Read safety manual frequently, especially before each season?barrelcollar around barrel becomes loosebarrel rotates sideways /becomes loose8loose connectes at collar5tighten all bolts before operation140Read safety manual frequently, especially before each season?Kevlar sheathepoxy doesn't holdshrapnel could fly out9barrel bursts and kevlar/ resin doesn’t hold1get expert advise on application process19Read safety manual frequently, especially before each seasonVertical aiminglift plate on uprightweld breaks loosebarrel falls7weak welds2have welds checked by certified welder114Read safety manual frequently, especially before each season?jacklift screw threads shearbarrels falls back to upright supports7crank not rated for that weight12 ton jack17?Horizontal aimingswivel plateinternal corrosionhorizontal aiming difficult4weathing4store cannon in covered location, protect from weather116??swivel plateweld breaks loosecannon could dislodge from base8weak welds2have welds checked by certified welder116Read safety manual frequently, especially before each seasonAccumulator Tanktankburstingno accumulator tank or barrel10defects in barrel1Kevlar sheath to prevent flying shrapnel220Read safety manual frequently, especially before each season?air fitting and pressure relief valveleakingpressure doesn’t hold7hairline fractures around fittings1inspect before each season214Read safety manual frequently, especially before each season?air hosetearing, disconnectair leakage7weathering, excess pressure1material type, screw in connection17Read safety manual frequently, especially before each season?butterfly valvecannon disconnect from accumulator tankshrapnel could fly out10bolts not tight enough1inspect before each season110Read safety manual frequently, especially before each seasonLaunch Protocol and ProcedureNotes:This is not the protocol for launching the final design. This is only for testing purposes to be carried out by cannon designers with safety officials present at all times.Two people must be present for all testing; one operator and one spotterWarning:Anyone within 20 feet of cannon should be wearing protective eyewear at all times.Only operator and spotter can be within 10 feet of cannon during testing.Phases:Loading (To be done by operator)Ensure the system is not chargedCheck that the stopcock is closedWith air pressure gauge, check accumulator tank for any pre-existing air pressureOpen bleeder valve to slowly release any pre-existing air pressureCheck pressure gauge again to ensure it reads zeroOpen launch valve to allow air to move freely between accumulator tank and barrelLower barrel to proper loading height and stand to the side of the barrel openingNever stand immediately in front of the barrelCheck barrel for obstacles or obstructions with plungerHandle of plunger has marks to show how far in it isFrom the side of the barrel, place sabot in the barrelInsert pumpkin (or surrogate projectile)Using plunger, push the pumpkin and sabot to the base of the barrelClose bleeder valveClose the launch valveCharging the systemSpotter: Ensure all bystanders are wearing protective eye wearEye wear must be worn during the entire testing procedureSpotter: Clear launch area to 180 degree lineOperator: Point barrel straight down launch areaHorizontal launch angle should be zeroVertical launch angle is maintained at 20 degreesOperator: Ensure trigger valve on cannon is closedOperator: Ensure bleeder valve is closedOperator: Open stopcockOperator: Pressurize accumulator tank to desired pressureBegin at 10 psig and progress by increments of 5 or 10 psigNever pressurize above 100 psigMonitor accumulator tank pressure by use of pressure gauge on bleeder valveLaunchingSpotter: Visually check that the launching area is clear and call out “Clear launch area and prepare for launch”Operator: Visually check launch area and call “launch area clearing, ready to launch”Operator: Release triggerBoth: Ensure sabot and projectile have cleared the barrelRepeat phases I-III as neededShutdown/LockoutDischarge the systemClose stopcockWith air pressure gauge, check accumulator tank for any pre-existing air pressureOpen bleeder valve to slowly release any pre-existing air pressureCheck pressure gauge again to ensure it reads zeroOpen launch valve to allow air to move freely between accumulator tank and barrelLower barrel to vertical angle of 0Place end cap on barrel to prevent weather damagePlace lock on trigger mechanismMath Model ................
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