Solid Motor Casing & Design

Solid Design Team:

Tony, Jason, Andrew, Tarique, Esteban, Jack 1

Quick Recap

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Motor and Propellant Selection● Non-Toxic

● Non-Detonable

● HTPB/AP/AL Composite

Aerotech L2200G-P Mojave Green

Design Process

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● Payload

● Drogue Chute

● Payload/Avionics

● Main Chute

● Motor and Casing

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What we know:● Peak Thrust ≈ 3100N

● Burn Duration ≈ 2.4s

● Dimensions

What we need to know:● Chamber Pressure

● Chamber Temperature

Motor Case Design Considerations

(in)

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What we know:● Peak Thrust ≈ 3100N

● Burn Duration ≈ 2.4s

● Dimensions

What we need to know:● Chamber Pressure

● Gas Exit Velocity

● Gas Exit Temperature

Nozzle Design Considerations

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What we know:● Motor Overall Performance

What we need to know:● Nothing

Igniter Considerations

Solid Rocket Motor

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● Case

● Solid Propellant

● Igniter

● Nozzle

Motor Case Loadings/Stresses

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(1)

Motor Case Materials● Composite

o E-glass

o Aramid (Kevlar 49)

o Carbon fiber

● Metalo Titanium alloy

o Alloy steel

o Aluminum alloy 2024

● Combination

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(1)

Composites

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(3)

Filament Winding

● Orientation of Filament

o Compromise

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(1)

12(1)

Metals

● Titanium alloyo Heavy

o Good strength to weight ratio

● Alloy steelo Heavier

o Strongest

● Aluminumo Provides good strength to weight ratio

o Lightest13

14(1)

Nozzles

There are five types

● Fixed (a)

● Movable (b)

● Submerged (c)

● Extendible (d)

● Blast-Tube-Mounted (e)

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Nozzles: Design and Construction

● Ablatively Cooled

● Steel or aluminum Shells

● Composite ablative liners

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Nozzle Design Decision

WE’RE NOT BUILDING ONE!!

Why?!?

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Nozzle Selection

● Aerotech L2200G-P Mojave Green and RMS

75/5120 kit comes with a nozzle

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Solid Rocket Motor ExpertRobert Watson

Robert at BuyRocketMotors.com

817-494-3834

rwatson@buyrocketmotors.com

www.BuyRocketMotors.com

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Igniters

Pyrogens

Pyrotechnic

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Igniters

Most frequent is Electroexplosive device

(Pyrotechnic)

● Bridgewire

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NASA- Solid Rocket Motor Igniters March 1971 pg. 45

http://electronicpackaging.asmedigitalcollection.asme.org/article.aspx?articleid=1408779

http://electronicpackaging.asmedigitalcollection.asme.org/article.aspx?article

id=1408779

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Field Trip?

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Summary● Motor Case: 2024 Aluminum Alloy

o Lightweight

o Capable of enduring thermal and pressure loads

o Machined or Off-The-Shelf (TBD)

● Nozzle: Built into Motoro Saves time and money

o Redundant to build additional nozzle

● Igniter: Bridgewire explosiveo Reliable

o Good “performance”

o Cheap

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Whats Next?

● Propellant Combustion

o Burn rate

o Flame Pattern

o Ignition Characteristics

● Propellant Stability

o Acoustic Resonance

o Ignition Wire Configurations

o Internal Gas Flow Cavity Considerations

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References

(1) Rocket Propulsion Elements, 8th Edition. Sutton, George P. and Biblarz, Oscar.

(2) Solid Rocket Motor Igniters. NASA

(3) Cowles, Devon K. "Design of a Rocket Motor Casing." Diss. Rensselaer Polytechnic Institute, 2012. Print.

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Questions?28