YikStik

A NAR L3 Certification Rocket

Bdale Garbee

+YikStik

YikStik

A NAR L3 Certification Rocket

Bdale Garbee

This document is released under the terms of the Creative Commons ShareAlike 3.0 @@ -14,11 +14,11 @@ Documenting the build process as it happens Revision 0.329 March 2008 Incorporate ideas from James Russell during initial L3CC review - Revision 0.227 March 2008Cleaned up for initial reviewRevision 0.116 March 2008Initial content

+ Revision 0.227 March 2008Cleaned up for initial reviewRevision 0.116 March 2008Initial content

Please note that I stopped adding photos to this document at some point. I have many more photos of the YikStik build, but haven't decided how best to present them yet... update coming someday! -

Chapter 1. Introduction

Table of Contents

Why "YikStik"?

Chapter 1. Introduction

Table of Contents

Why "YikStik"?

This is the rocket I'm designing for my NAR Level 3 certification flight. The general idea is to build a fairly cheap rocket capable of reliably flying this year's Aerotech level 3 special, which is an M1297W reload. @@ -38,7 +38,7 @@ could safely fly on reloads as small as a J for economical fun. Those altitudes mean the certification flight will need to be at a site with a high-altitude waiver like the NCR north site. -

Why "YikStik"?

I've always thought the high-gloss red paint job on one of my son's rockets when out on a launch rod in the sun looks a lot like glistening wet lipstick. @@ -50,7 +50,7 @@ can, which is the mental image I have of what lipstick applicators look like, most likely from a stick my mother or one of my grandmothers had when I was a child. -

Chapter 2. Design

Table of Contents

Overview

Rocksim File

Drawing from Rocksim

Airframe Tubing

Nose Cone

Fins

Centering Rings and Bulkheads

Motor Retention

Electronics

Avionics
Payload

Stability Evaluation

Expected Performance

Recovery System

Overview

Chapter 2. Design

Table of Contents

Overview

Rocksim File

Drawing from Rocksim

Airframe Tubing

Nose Cone

Fins

Centering Rings and Bulkheads

Motor Retention

Electronics

Avionics
Payload

Stability Evaluation

Expected Performance

Recovery System

Overview

YikStik is a fairly simple "three fins and a nose cone" dual-deploy rocket using a 75mm motor mount, 4 inch glass-wrapped phenolic airframe with zipperless fin can, plastic nose cone, plywood fins, @@ -58,17 +58,17 @@ The primary electronics bay will be designed to hold two altimeters, and a distinct payload bay may carry an experimental altimeter, GPS receiver, and downlink transmitter. -

Rocksim File

This is the current working design in Rocksim format: - YikStik.rkt

Drawing from Rocksim

Airframe Tubing

+ YikStik.rkt

Drawing from Rocksim

Airframe Tubing

I intend to cut the airframe components from two 48 inch lengths of 98mm Giant Leap Dynawind tubing. The 30 inch main bay and 18 inch drogue bay will be cut from one length, while the 33 inches of fin can, 2 inches of electronics bay, and 8 inches of payload bay will be cut from the second. -

Nose Cone

I intend to use a Giant Leap "Pinnacle" 3.9 inch nose cone. -

Fins

The fins are designed from scratch, and I intend to build them up from two layers of 1/8 inch birch plywood, three layers of carbon fiber, and two layers of 6 oz glass. The stack will be glass, carbon fiber, @@ -85,18 +85,18 @@ The airframe will be slotted to allow the completed motor mount / fin assembly to be inserted from the rear, with fillets of epoxy applied inside and outside the airframe after insertion. -

Centering Rings and Bulkheads

All centering rings and bulkheads will be custom machined from 3/8 inch birch plywood using my 3-axis CNC milling machine. Some rings will use laminated pairs of 3/4 inch total thickness to enable use of threaded inserts for 1/4-20 rail button screws or deep routing for fin alignment slots. -

Motor Retention

I will embed three 8-24 T-nuts in the aft centering ring spaced to allow the use of home-made Kaplow clips to retain 75mm motors. The same holes may be used to attach custom motor mount adapters for smaller diameter motors. -

Electronics

Avionics

Electronics

Avionics

The recovery system will feature dual redundant barometric altimeters in an electronics bay similar to the LOC design located between the drogue and main parachute bays. @@ -109,7 +109,7 @@ Each altimeter will have a separate battery and power switch. A 4PDT slide switch will be used as a SAFE/ARM switch configured to interrupt connectivity to the ejection charges. -

Payload

I hope to fly my own altimeter design @@ -121,7 +121,7 @@ This is not essential to fly, but could make recovery simpler and would just be fun to fly if I can get it all working and suitably ground and/or flight tested in time. -

Stability Evaluation

This design has been thoroughly analyzed using RockSim @@ -134,7 +134,7 @@

These simulations will be refined as the build proceeds and as-built stability verified before flight. -

Expected Performance

The Aerotech M1297W reload should carry this vehicle without ballast to just over 14 thousand feet AGL. It should make over 16 thousand feet AGL on an M1850W, and should fly stably to roughly 2.5k feet AGL @@ -147,7 +147,7 @@ If the cert succeeds, then I might try an optimal mass flight sometime later on an M1850W or equivalent "bigger M" reload to join the "three mile club". -

Recovery System

The recovery system will use dual redundant barometric altimeters firing black powder charges. At apogee, a drogue chute will deploy from just forward of the fin can, @@ -180,14 +180,14 @@ of 1/2 inch tubular kevlar, bonded to the motor mount. If available, a screw-eye attached to the forward motor closure may be used instead of or in addition to this recovery attachment loop. -

Chapter 3. Construction Details

Table of Contents

Airframe and Couplers
Fins
Centering Rings and Bulkheads
Assembling the Booster Section
Avionics Bay
Payload Bay
Recovery System

Chapter 3. Construction Details

Table of Contents

Airframe and Couplers
Fins
Centering Rings and Bulkheads
Assembling the Booster Section
Avionics Bay
Payload Bay
Recovery System

I have collected all of my build photos in one place, they may show better than I can explain how various aspects of YikStik went together. -

Airframe and Couplers

The tubing for the airframe, couplers, and motor mount was all cut using a carefully aligned and adjusted power mitre saw, and the ends lightly sanded to remove rough spots. @@ -220,7 +220,7 @@ after reinforcing to get "perfect" ends. The technique worked marvelously otherwise, and the resulting couplers look and should work great! -

Fins

Six pieces of 1/8 inch birch plywood were stacked, edge-aligned on what would be the fin root edge, and clamped. The outline of the fin design was marked in pencil, and three 1/8 inch holes drilled through the @@ -278,7 +278,7 @@ sides were done one at a time and allowed to cure before proceeding. The results look good, and in combination with internal and external airframe filets should yield a super-strong fin can. -

Centering Rings and Bulkheads

Pairs of 3/8 inch birch plywood blanks were laminated using Titebond wood glue and clamped while curing to form 3/4 inch blanks for centering rings. From a strength perspective, 3/8 inch should suffice, but there @@ -297,7 +297,7 @@ 1/4-20 threaded inserts to hold rail buttons. The inserts were locked in place with epoxy, then ground down until nothing protruded beyond the OD of the ring. -

Assembling the Booster Section

The forward two centering rings were installed on the MMT using JB Weld high-temperature epoxy, and incorporating an aircraft cable loop for recovery system retention since there just wasn't room for @@ -349,7 +349,7 @@ motor mount and zipperless-design coupler tubing was filled with epoxy and milled glass. Minor gaps in the airframe behind each fin were filled with epoxy clay. -

Avionics Bay

The avionics bay contains the two commercial altimeters used to record information about the flight and deploy the drogue and main recovery systems. It is constructed of a piece of Giant Leap 98mm @@ -414,7 +414,7 @@ formula for a bay over 100 cubic inches the answer is 0.261 inches. The closest standard drill size, which happens to split the difference, is 0.250 inches. Easy enough! -

Payload Bay

The construction of the payload bay is very similar to the avionics bay, except that there is a hard-epoxied rear bulkhead, and only one screw ring to hard-mount the nose cone. The forward end of the @@ -422,7 +422,7 @@ anticipation of extending downlink antennas above the carbon fiber reinforcement in the coupler and into the nose cone, since carbon fiber is opaque to RF. -

Recovery System

Pre-sewn 1/4 inch tubular kevlar harness sections were purchased from Giant Leap, along with a small kevlar deployment bag and two kevlar chute protectors. @@ -457,7 +457,7 @@ and its main charge at 900 feet. Thus the MAWD is primary and the miniRRC2 is the backup. Since the M1297W has a burn time of about 5 seconds, mach inhibit is programmed on both altimeters to 8 seconds. -

Chapter 4. Recovery Systems Package

Table of Contents

Recovery System Description
Recovery Initiation Control Components

Recovery System Description

Chapter 4. Recovery Systems Package

Table of Contents

Recovery System Description
Recovery Initiation Control Components

Recovery System Description

This rocket uses dual deployment.

The apogee event separates the @@ -488,7 +488,7 @@ The anchor points are all 5/16 inch u-bolts, except for on the booster which is equipped with an embedded loop of 3/16 inch stainless aircraft cable. All connections are made with suitable quick-links. -

Recovery Initiation Control Components

The LOC-style avionics bay between the main and drogue bays is populated with two commercial altimeters, a PerfectFlite MAWD and a Missile Works miniRRC2. @@ -553,7 +553,7 @@ the designers of this chute pattern, sanity checked using the descent rate tables of similar commercial parachute designs, like those from The Rocketman. -

Chapter 5. Stability Evaluation

Simulation using Rocksim v8 with a variety of motors showed that the rocket is unconditionally stable with all motors likely to be flown. The worst-case stability among 75mm motors is actually with the @@ -565,7 +565,7 @@ The smallest motor I can conceive of flying in this rocket (a Cesaroni J285) would leave us overstable with margin 3.79 on the way to about 1800 feet apogee. -

Chapter 6. Expected Performance

On the certification flight, using an Aerotech M1297W reload and associated hardware, the anticipated apogee is round 14,700 feet. This is just under 75% of the NCR North Site standing waiver of 20,000 feet. @@ -577,7 +577,7 @@ add description of anticipated flight profile here, including launch weight, estimated drag coefficient, velocity leaving the rail, max expected velocity, altitude, and acceleration -

Chapter 7. Checklists

Planning
1. Pick a club launch with suitable waiver and facilities to @@ -759,7 +759,7 @@ gather up and roughly re-pack recovery system for return to flight line
2. bring the rocket to observers for post-flight inspection -

Chapter 8. Flight Summary

YikStik was flown on an M1297W on Saturday morning at NCR's Oktoberfest 2008. The boost was beautiful. Unfortunately, we lost visual as the rocket climbed into high clouds near apogee. Radio tracking signals @@ -777,7 +777,7 @@

Reward if returned posters were placed in the area during the week following the launch but have elicited no useful reponses yet. -

Chapter 9. Analysis and Conclusions

Consideration of how the nose cone ended up where it did suggests we may have had an apogee deployment of the main, perhaps due to stress on the shear pins before launch, during boost, or during