A Guide to Level 2 Rocket Design
What's different about a level 2?
A level 2 is more complex in every aspect of construction and design
They also have much more space for variability and design!
This guide will touch on the basics of a level 2
Airframe Design
Airframes for level 2's are commonly made of 4" OD cardboard tubing
This tube is then reinforced with a fiberglass and epoxy composite to drastically increase strength
This is a necessity to prevent damage on landing and resist aerodynamic forces during flight
Airframe Design
Fin sets are designed using the same methods as a level one
Trapezoidal fin sets are highly recommended to avoid damage on landing
These are often made with ¼ " plywood and are then filleted and "tip to tipped", or reinforced with a fiberglass and epoxy composite
Airframe Design
Bulkheads are necessary for several reasons:
- They provide anchor points for shock cord
- They create a vacuum to allow proper separation
- They protect the electronics inside your rocket
Bulkheads are often made with plywood, fiberglass, composites etc.
Airframe Design
Ventports are necessary for two primary reasons:
- They maintain pressure equilibrium between the atmosphere and the body tube's interior
- They allow the altimeter to detect pressure changes due to the atmosphere and calculate altitude
Only a few are necessary and their specs are often listed in the manual of whatever altimeter you decide to purchase
Recovery
The recovery system of a level 2 is by far the biggest difference from a level 1 rocket
Level 2's utilize a "dual deployment" recovery system designed to use a small drogue parachute at apogee for a quick descent, and then deploy a larger main parachute at a specified altitude for a safe landing
This system utilizes an electronics bay equipped with an altimeter, power supply, black powder charges and an activation switch
The Ebay is made in the coupler section of the rocket with strong bulkheads on both sides and should be about 8" long but can vary
It holds the airframe together, is the point of separation for parachute deployment, and contains the electronics
The Electronics Bay
1) Altimeter�2) Power Supply�3) Switch Mechanism�4) Sled�5) Threaded Rod�6) Copper Tubing�7) Shock Cord Anchor�8) Terminal Blocks
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1) Altimeter
1)
The altimeter is the most important part of the Ebay. Everything else that makes up the Ebay is designed to support it in some fashion. Its job is to detect pressure differences or changes in acceleration (depending on the model) to determine the altitude.
When the rocket reaches apogee, the altimeter will trigger the deployment of the drogue parachute. Then, the altimeter will deploy the main chute at a chosen altitude, at around 500-800 feet. The setup for the altimeters you can use (RRC2+, Stratologger, etc.) vary, but the manuals provided have all the information you need to operate and set them up.
2) Power Supply
2)
A 9 Volt battery is often used to power the electronics bay of a level 2 design. While this can vary depending on the altimeter used, it is the most common power source.
3) The Switch
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The switch mechanism is the device that turns on the components of your Ebay. There are many kinds of switches that work well for this application, but they must be accessible while the rocket is on the launch rail. In this example, a "key switch" is being used, all it takes is a specialized key to turn it like a lock to turn on the electronics. Other examples include a "button switch" and a "flip switch".
4) The Sled/Mount
4)
The sled is the component on which the altimeter and power source are mounted. There are an endless number of ways to design sleds to suit the needs of each individual rocket. This example is a 3D printed sled that was designed using SolidWorks.
WARNING: While 3D printing is very versatile, strength characteristics of these printed polymers perform much poorer under the stresses of a rocket launch than other materials. Consult someone with experience and tread lightly!
5) Threaded Rod
5)
A threaded rod is used to firmly attach the sled to both sides of the Ebay bulkheads. This must be built very strong to avoid vibrations during flight!
6) Copper Tubing
6)
The end of a copper tube is screwed and epoxied to both bulkheads to each side of the Ebay to store black powder charges for parachute ejection. The tube is strong enough to hold up against the charge and direct the blast energy away from your Ebay and eject your parachutes.
7) Shock Cord Anchor
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Both sides of the Ebay must have an anchor for parachute shock cord to attach to. There are many ways to do this, so choose at your own discretion. This example uses a U-Bolt configuration on both sides.
8) Terminal Blocks
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In order to create the necessary connections between the altimeter and the actual ejection charge, two terminal blocks are needed on each side of the Ebay that connect the altimeter to an igniter (not displayed).
Motor Selection
The motor impulse class of a level 2 lies under the J, K, and L impulse range with total impulses from 640 N•S to 5120 N•S
Motors of this strength can range from 38mm, 54mm, 75mm, or 98mm in diameter
This is an example of an Aerotech 38mm J-425
Ask us questions!!!
Level 2 rockets can be very complex and are much more involved than a typical level 1
Send one of us an email or stop by the Rocket Lab in W0005, we are always looking to help!
Dan Lawson – Tripoli Project Manager
DJLYRD@mail.missouri.edu
Evan Kahle – Treasurer
Kahlee@missouri.edu
Mark Magnante – Vice President
Mam5r5@mail.missouri.edu
Wyatt Fritsch – President
Jwfhxf@mail.missouri.edu
Sam Reid – USRC Manager
Samuel.reid@mail.missouri.edu
Cale Crawford – Propulsion Lead
Calecrawford@mail.missouri.edu