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Cliff Oliver’s Level 3 Project

National Association of Rocketry High Power Level Three Certification Package

Rocket Designed, Built and Flown By:

Cliff Oliver, NAR # 77417

High Power Level 2

 

Temporary Insanity

 

Introduction

 

Temporary Insanity is a single staged three finned rocket. The design is an upscale loosely based on the Aerotech Mustang mid-power model rocket. The differences are the shape of the nose cone and number of fins. My project has three clipped delta fins.

The basic dimensions are:

  • Length: 9 feet 10 inches

  • Diameter: 7.51 inches

  • Launch weight: 45 pounds

  • 98MM motor mount / 75MM adaptor

The certification flight will be on an Animal Motor Works M1850GG motor. According to simulations performed with Rocksim 8 software, using this motor will yield an altitude of approximately 6000 feet AGL.

The design if this rocket uses two altimeter bay tubes. They are positioned parallel to the airframe and to each other on each side of the inside of the airframe. Static port holes are drilled thru the airframe and the altimeter bay tubes. The power and shunting switched are mounted on the altimeter sled and are accessible thru these port holes. The main ejection charge holders are 12 inches long and extend from the aft altimeter bulkhead to the main payload section. All electronics, associated wiring, switches and ejection charge holders are mounted on sleds which are attached to a removable cover plate. This facilitates easy accessibility to the electronics and ejection charges.

 

Scale Drawings

Scale drawing showing major components and their dimensions.

 

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This scale drawing show the CP and aft CG limit of the rocket. These calculations were made using Rocksim 8 software.

 

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This is the two dimensional drawing generated using Rocksim 8. The rocket is shown loaded with the AMW M1850GG motor.

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This is a 3 dimensional image of my design generated with Rocksim 8.

 

 

Construction

 

Construction began by gathering parts. Below are the fins made of 3/8 inch plywood, ½ inch plywood centering rings, three ½ inch and one ¼ inch bulkheads. The nose is from LOC/Precision. It is 7.5 inches in diameter and made of plastic.

 

 

Next are the two 54MM tubes for the altimeter bays, 98MM motor tube, phenolic body tubes, and phenolic tube liners. The airframe tubes are shown with the first layer of card board peeled from the forward ends in preparation for reinforcement with Kevlar tape.

 

 

Three inch Kevlar tape reinforces the forward ends of both body tubes. This step will strengthen the tube ends to prevent a zipper.

 

The entire airframe was reinforced with phenolic liners. The liners were secured in place with marine grade epoxy.

 

The booster section attachment points for the recovery harness are 5/16 inch U-bolts. Fender washers on the underside of the center ring provide greater support.

 

 

Three 8-32 T-nuts were installed in the aft centering ring to use as motor retention. A Slimline retainer/adapter will be installed in a later step. Screws will engage the outer flange of the retainer to provide greater security for the retention system.

 

The fins were attached to the motor mount with marine grade epoxy. Colloidal silica was added to the epoxy for strength.

 

A layer of 6 ounce fiberglass was laid between each fin and reinforces the fin tab to motor mount joint.

 

The aft centering ring was not installed until the fin can was secured in the aft body tube and the interior fin fillets were completed.

 

 

Here, the aft centering ring is installed. Epoxy thickened with colloidal silica was placed on the outside of the motor mount and the inside of the body tube. Then the centering ring was installed. A fillet was added t the body tube centering ring joint. A Slimline motor retainer will be added during a later step.

 

 

This is view of the upper centering ring with the U-bolts installed into the booster section

 

Exterior fin fillets were added using epoxy and colloidal silica for the first layer. The second layer is epoxy and phenolic micro balloons.

 

 

A 1/8 inch hole is drilled into the booster section to equalize interior airframe pressure to ambient pressure during flight to prevent premature separation of the sections.

 

Here, I am installing a threaded brass insert into the lower centering ring for the lower rail button. I drilled the holes into the rings large enough for the insert. Then applied thickened epoxy to the hole and screwed the insert in until it is flush with the airframe. The upper rail button is attached to the forward centering ring using the same method. The buttons are Series 1500 Delrin from Railbuttons.com.

The payload section is also on the bench with the spiral filler drying. The large white section at the bottom is actually the top of the section where the Kevlar tape has been used for reinforcement.

 

1500 Series Delrin rail buttons are installed into the brass inserts for guidance.

 

A Slimline motor retainer was installed using JB Weld and three 8-32 screws and T-nuts. A Slimline 98/75mm motor adaptor is used to mount the AM M1850GG motor.

 

The altimeter bay consists of three ½ inch plywood bulkheads. Two of them have been cut to accept two 54MM tubes that house the avionics with associated switches and wiring and two 24MM holes for the conduit tubes. A 5/16 inch threaded rod is attached to all three bulkheads for reinforcement

 

 

Two 24MM tubes are used to allow easy passage of the main ejection charge holders to the forward payload section. The two ¼-20 bolts secure the cover plate to the assembly.

 

Here the altimeter bays are installed into the forward payload section.

 

 

This is the view of the inside of the payload section. The two large holes are where the ejection charge holder/conduits come into the bay. The four smaller holes have been filled with epoxy

 

This is the cover plate for the altimeter section. The main ejection charge holders/conduit made of PVC tubing and altimeter mount sleds are attached to this. Three apogee ejection charge holders are made from PVC couplers cut to facilitate ejection charges. The wiring blocks are labeled to ensure proper connection of the igniter leads. The PVC caps cover the ends of the main ejection charge holder/conduit. They are slotted on the side to allow the igniter leads to pass. A small screw will secure them during flight. The two eye bolts are pull handles to aid in removing the assembly from the rocket.

 

 

Attached to the sleds is a Perfectflite MAWD, MT3G timer and a Missile Works RRC2 altimeter. Each of the three devices is equipped with its own power supply, power switch, shunting switches and ejection charges. Each ejection charge has its own shunting switch.

This entire assembly slides into the 54MM and 24MM tubes in the altimeter section. Coupler tubing located at both ends of the sleds seal the altimeter bay tubes. The PVC tubes are ejection charge holders and conduits for the igniter leads.

 

 

Here the cover plate is installed into the altimeter bay. Wing nuts (not shown here) are used to secure the plate to the rocket.

 

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Static portholes are drilled through the airframe and altimeter bay tubes on both sides of the rocket. This allows access to the power and shunting switches mounted on the altimeter sleds using a small flat blade screw driver.

 

 

 

Here, I am sanding the filler on the payload section.

 

A 3/8 x 4 inch eye bolt is secured in the nose cone bulkhead by a nut and washer on the exterior. On the interior there is a fender washer and nut. A 24 inch length of threaded rod is attached to the remaining eye bolt threads with a threaded coupler. The forward end of the rod extends to the tip and is embedded in a mixture of epoxy and BB’s. This mixture is used for nose weight to ensure the proper stability.

 

 

2-56 nylon screws act as shear pins. Both separation points utilize three each.

 

 

Recovery System

A 60 inch x-form drogue chute will be deployed at apogee by black powder ejection charges controlled by a Perfectflite MAWD and a Missile Works RRC2 altimeter. These altimeters are backed by a Perfectflite MT3G timer set to fire approximately 22 seconds after launch. Each device fires its own charge. The drogue will slow the rocket’s descent to approximately 57 feet per second and orient the payload section to prevent fly thru of the main parachute upon its deployment.

At approximately 1000 feet AGL, the main 98 inch diameter TAC9-B parachute will be deployed by black powder ejection charges controlled by a Perfectflite MAWD and a Missile Works RRC2 altimeter. A deployment bag will be used to ensure proper deployment of the main chute. A 48 inch diameter parachute which is attached to the nose cone will pull the bag off of the main chute. The nose cone and deployment bag will descend separately at approximately 17 feet per second. The main parachute will land the rocket at approximately 15 feet per second.

The drogue parachute compartment is located in the booster section and the main parachute compartment is located in the payload section of the rocket. Masking tape will be used to adjust the fit of the coupler and nose cone to the airframe. Three 2-56 nylon screws will be used as shear pins at both separation points to prevent premature separation and deployment of the recovery systems.

A harness made from 4 feet of 2 inch nylon webbing is attached to the two U-bolts installed into the booster section upper centering ring. Attached this way, the webbing forms a “V” shape. The shock cord, which is 100 feet of 1 inch tubular Kevlar, is attached to this point. The drogue is a 36 inch diameter nylon chute from LOC/Precision. Quick links are used to attach the harness to the booster and payload sections as well as the drogue. Swivels are also used where twisting of the harness is expected. A Nomex chute protector along with cellulose insulation (dog barf) is used to protect the drogue recovery components.

6 feet of 2 inch nylon webbing is attached to the U-bolt installed into the forward bulkhead of the altimeter bay. The aft end of the webbing is covered by a Nomex sleeve to protect it from ejection charge heat. A Giant leap TAC9-C parachute is attached to one end of 100 feet of 1 inch tubular Kevlar shock cord. The 2 inch nylon webbing attached to the other end. The main chute is incased in a deployment bag. This bag is attached to the nose cone and a 60 inch diameter parachute via a harness. Upon deployment of the main recovery system the 60 inch chute will inflate and pull the bag from the main chute. The nose cone and deployment bag will descend separately on the 60 inch chute. A Nomex chute protector and cellulose insulation will protect the recovery components from ejection charge heat.

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Stability Evaluation

The certification flight will be on an AMW M1850GG. At liftoff the minimum Aft CG at 77.3 inches and the CP at 89.2 inches from the nose tip. This gives the rocket a stability margin of 1.55 calibers. According to Rocksim flight simulations, the margin should not drop below 1.55 during the flight.

 

Expected Performance/Flight Profile

Using an AMW1850GG motor, simulations for different wind/weather conditions were run. Simulations with light winds of 3 to 7 mph, slightly breezy wind of 8 to 14 mph and winds of 15 to 25 mph were run using Rocksim v.8 software.

General flight profile is as follows.

  • Max velocity: 869ft/s

  • Time to burn out: 3.2 sec

  • Time to apogee: 20.6 sec

  • Altitude at apogee: ~7000 ft

  • Velocity at drogue deployment: 43 ft/s

  • Descent velocity under drogue: 50 ft/s

  • Altitude at main parachute deployment: 1000 ft

  •  Descent velocity under main parachute: 15 ft/s

  • Total time of flight: 164 sec

Checklists

Pre-Launch Preparation

Equipment

__ Motor assembly lube

__ Motor mount adaptor

__ Motor retainer wrench

__ Tool kit – screw drivers, wrenches, pliers, wire cutter/stripper

__ Small parts box – shear pins, extra rail buttons, screws, quick clips

__ Canopy

__ Camp table

__ Rocket cradles

__Chair

__ Trash bag

__ Paper towels

__ Handi wipes

__ Cooler – water, soda, Gatorade, snacks

__ Camera

 

Procedures

 

__ Assemble motor according to manufacturer’s instruction sheet

__ Insert the assembled motor into the 98/75 Slimline motor adapter and secure with retainer ring. Hand tighten the ring with supplied tool

__ Insert the motor/adapter assembly into the motor mount tube of the rocket and secure with retainer ring. Hand tighten with supplied tool

__ Ensure that all motor retention hardware is in place and secure. Check with appropriate tool(s)

__ Assemble motor igniter onto wood dowel according manufacturer’s recommendations

__ Tape the assembled igniter onto the outside of the booster section airframe opposite from the rail buttons. (For later installation into the motor on the pad)

__ Attach 2 inch shock cord strap onto the booster section u-bolts with quick links

__ Attach drogue shock cord onto the installed strap

__ Attach the drogue parachute to shock cord

__ Pack drogue parachute and shock cord into the booster section. Cover with chute protector

__ Allow the remaining shock cord connection to rest on top of the installed chute protector for later attachment to the payload section

__ Ensure that all altimeter switches are in the safe (220V) position

__ Test three new 9 volt batteries to ensure proper voltage of approximately 9 volts

__ Install the tested good batteries into the battery holders on the altimeter mount sleds and RRC2 altimeter

__ Install and ensure that the battery retaining clip on the RRC2 is tight against the battery

__ Install nylon wire ties around the tops and sides of the batteries and holders mounted on the sleds

__ Set the RRC2 program switches as follows

SW1-ON SW2-OFF SW3-OFF SW4-OFF SW5-OFF SW6-OFF

__ Set the MAWD program switches as follows

SW1-ON SW2-OFF SW3-OFF SW4-OFF SW5-OFF SW6-OFF

__ Set MT3G timer to 22 seconds per manufacturer’s instructions

__ Fill two ejection charge canisters with 5 grams of 4F black powder. Cap with wadding and tape. Label the top of the charges with a “5” to denote a 5 gram charge

__ Fill three ejection charge canisters with 2 grams of 4F black powder. Cap with wadding and tape. Label the top of the charge with a “2” to denote a 2 gram charge

__ Insert the igniter lead of one “5” charge into the main ejection charge holder conduit until the charge is resting against the end of the conduit. Secure the charge with tape. Perforate the end cap tape to direct gases forward

__ Repeat for the second “5” charge

__ Trim the installed igniter leads to reach their designated terminal blocks. Strip the ends approximately 1/8 inch and install into the designated terminal block connection

__ Install the two conduit caps and secure with nylon wire ties

__ Install three “2” charges in the ejection charge holders on the aft end of the altimeter bay cover plate. Allow the igniter leads to rest in the slots cut into the side of the holders. Secure with tape. Perforate end cap tape to direct gases forward

__ Trim the installed igniter leads to reach their designated terminal blocks. Strip the ends approximately 1/8 inch and install into the designated terminal block connection

__ Ensure that all wiring connections at terminal blocks are tight. Check with screw driver

__ Ensure that all wiring connections at the altimeters and timer are tight. Check with screw driver

__ Inspect all wiring, switches and devices to ensure no damage or loose connections or mounts

__ Install altimeter package into the payload section until cover plate is flush with the end. Secure with two washers and wing nuts

__ Ensure that main ejection charges are in place inside the payload section

__ Check to ensure the 2 inch shock cord strap is secured to the payload section u-bolts

__ Check that the shock cord protector is covering aft end of the 2 inch strap

__ Attach the main parachute cord to the 2 inch strap

__ Attach the main parachute the main shock cord

__ Pack main chute in the deployment bag per manufacturer’s instructions

__ Attach pilot chute to the deployment bag

__ Attach nose cone to pilot chute shock cord

__ Pack shock cord into the chute protector

__ Insert packed shock cord and deployment bag into payload section

__ Pack pilot chute and shock cord into chute protector

__ Insert packed pilot chute and shock cord into the payload section.

__ Install nose cone while aligning the marks on the shoulder and inside the airframe

__ Install one shear pin into each of the three holes to secure nose cone

__ Attach the remaining drogue chute shock cord to the payload section aft u-bolt

__ Inspect the drogue chute and shock cord to ensure proper placement

__ Mate the booster and payload sections. Align the marks on the coupler shoulder and inside airframe

__ Install one shear pin into each of the three holes to secure the sections together

__ Check to ensure the rail buttons are installed properly and the fasteners are tight. Check with screw driver

__ Review check list

Launch Checklist

Equipment

__ Small flat blade screw driver

__ Small piece of sandpaper (to clean igniter clips

__ Extra shear pins

__ Tape

__ Flight card

__ Igniter (should be tape to rocket)

__ Small step stool/ladder

__ Camera

 

Procedures

__ Load rocket onto the launcher

__ Verify/adjust launcher angle

__ Install igniter (Do not connect to launch system)

__ Arm recovery devices (start at top switches and turn clockwise)

__ Verify proper audible ready indicators from devices

__ Connect igniter to launch system

__ Verify flight witnesses are ready

__ Notify LCO/RSO of readiness for flight

 

Post-flight Checklist

__ Verify all pyrotechnics are discharged

Safe recovery system if live charges exist

Attempt to determine reason for malfunction

__ Return all shunts to the safe position (turn switches counter-clockwise)

__ Power down MAWD and timer (flight data will be recovered later)

__ Translate and record altitude from RRC2

__ Power down the RRC2

__ Return rocket to flight witnesses for inspection

 

Contingency Checklist (For misfire, aborted launch or crash)

__ Safe igniter shunts (turn switches counter-clockwise)

__ Power down recovery devices (turn switches counter clockwise)

__ Disconnect and remove motor igniter

__ Judge operational time of recovery devices to determine if batteries require replacement for another launch attempt (misfire/abort)