Madcow 5.5-inch Nike-Tomahawk Rocket

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I purchased this rocket from one of Madcow’s “hump day” email specials. The discount from the retail price was fantastic. This sale actually got me fired up to do some big projects for LDRS 38. This page will document the build, finishing, and launch of the Madcow 5.5-inch Nike-Tomahawk rocket.

OpenRocket Diagram - Madcow 5.5-inch Nike-Tomahawk Rocket
OpenRocket Diagram

Kit Contents

The kit arrived in good condition. I washed all the parts with warm soapy water. The fins had some kind of goo on them but it was easily removed with acetone.

Washed rocket parts - Madcow 5.5-inch Nike-Tomahawk Rocket
All Washed Up and Ready to Go

The parts were inventoried and marked. I measured and weighed all the parts and started a fresh OpenRocket configuration for the build. You can find the OpenRocket file below.

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There are no detailed instructions for this kit, but I figure Madcow thinks you should know what you are doing if you are buying this kit — whether that is true is a point of contention.

Build

Booster Motor Mount and Fin Can

The booster diameter is 5.5 inches. I have a thrust plate of that size from my Tripoli Level 3 rocket, BOTC 84. It will be used on this project. To hold the plate in place, three low-profile t-nuts are attached (using JB Weld) to the lower centering ring.

Lower Centering Rings Nuts - Washed rocket parts - Madcow 5.5-inch Nike-Tomahawk Rocket
Thrust Ring Bolt Connections

Two forged iron eyebolts are used to connect the booster recovery system to the motor mount. A Kevlar Y-harness will be connected to the eyebolts with D-rings

Booster Motor Mount Recovery Attachment - Madcow 5.5-inch Nike-Tomahawk Rocket
Motor Mount Eyebolts

The motor mount assembly is epoxied into the booster body tube at the correct position to insure a flush fit of the thrust ring to the base of the tube. Each fin is sanded and tacked to the motor mount through the slots in the body tube. Holes are drilled into the body tube to allow the application of fillets to the fin-to-motor mount connection.

Once all internal fillets were completed, the external fin-to-body tube fillets are applied.

Unique Engine Models
External Epoxy Fillets - Madcow 5.5-inch Nike-Tomahawk Rocket
External Epoxy Fillets

Got the fins on the sustainer and filleted them with cut carbon fiber. Finished the construction of the booster-to-sustainer transition.

Full stack assembled
Test Fit the Stack

Electronics

The basic sequence of events is as follows:

  1. Booster motor ignition
  2. Booster motor burn out (BBO)
  3. Rocket separation charge firing (BBO + 0 sec)
  4. Sustainer motor ignition (BBO + 4 sec and rocket < 20 degrees from vertical)
  5. Booster chute deployment
  6. Sustainer motor burn out
  7. Drogue deployment
  8. Main deployment

The electronics will be housed in three locations on the rocket:

  • Nose cone ( camera )
  • Sustainer EBay ( dual deploy and sustainer ignition)
  • Booster-to-sustainer Coupler ( separation and booster chute deployment)

OpenRocket File

This is the OpenRocket file I created for this rocket project: Nike-Tomahawk. It will be updated as the build continues.

Launch(es)

First launch is planned at LDRS 38 near Argonia, Kansas on Labor Day weekend 2019.