Hi, matey, me name is Mark Shamburg-Donohue. Well, blow me down! I'm a 17 year old high school junior. Arrr! Blimey! I live in Denver, Co.Ýand I've been flyin' model rockets since I be 12. I just got into high power rocketry this winter when I fired an Aerotech 1357T reload for a physics class project

My favorite subject is chemistry and I have done a lot o' work in t' chemistry area o' rocketry. Arrr! Avast, me proud beauty! I am currently designin' a hybrid motor, that I would like t' build this summer. T' motor employs certain unique design features, which I think will make it a very interestin' project. Aye aye! I plan t' patent t' design if all goes well.

A science teacher/ friend/ head o' IAAS (science club)/ all around great guy, named Jim Moravec is helpin' me find an internship in one o' t' many aerospace companies in Colorado. Aye aye! I will be startin' college in t' fall o' 2001, and would like t' major in chemistry, with minors in either mechanical engineering/draftin' or physics. Avast! Begad! Once I graduate I would like t' work for either t' military or t' aerospace industry developin' propulsion systems. I would also like t' get a master degree in chemistry.

This is me first high power rocket. Ever since I downloaded VCP about six months ago, shiver me timbers, I've designed over 50 rockets. This rocket be initially named t' "She's a Goer" after t' B-29 me grandfather flew over Korea, and be designed t' slightly resemble t' beautiful bird. Well, blow me down! Blimey! Avast! Blimey! T' rocket originally had a 1.5" long elliptical nose cone, me hearties, but do t' unavailability o' this (more aerodynamically sound) design I had t' settle on a 9.5" long tangent ogive. Avast! Blimey! Ahoy! Blimey! Since t' design no longer resembles t' She's a Goer, shiver me timbers, I had t' come up with a new name for it. Begad! Blimey! Since t' rocket nowÝresembles a missile I decided t' give it a military soundin' name. Blimey! Blimey! I settled on "Mark 1X". The "1X" comes from this bein' t' first design o' me own that I've built and t' fact that its an experimental design. Ahoy! Blimey!

Unlike some entries that are just modifications on pre-existin' rockets this is an entirely original design. This baby has 12 fins! Some people might think that havin' 12 fins makes t' rocket overly difficult t' build but the advantages outweigh t' difficulty o' buildin' it, which by t' way be no more difficult than any other rocket (only slightly more time consuming). Most o' t' surface area comes from t' main fins, me hearties, arrr, which are located 2.5" from the bottom and have a surfaceÝarea o' 11.625 sq." each. T' aforementioned advantages come from t' canards which are small fins at t' front o' t' rocket which don't have a large enough surface area t' create any stress problems but function t' split t' air stream and lower t' amount o' turbulence created by t' main fins. T' rear fins are mostly cosmetic, shiver me timbers, but also add t' lower t' amount o' turbulence whenÝ t' air stream closes around the end o' t' rocket. Ya scallywag!

Here's t' same launch, about 5 feet higher in t' air, that's me dad on t' left. Blimey! This picture be taken by my dad's friend Tery Okumura. Ya scallywag! Thanks Tery!

Here's a picture o' me settin' up for t' next shot. Avast! Blimey! Blimey! Blimey! This one is about t' be lifted off on a G80 and lofted to about 2200 feet. Blimey! Blimey! Aye aye! Blimey! Blimey! Blimey! I didn't know it yet but this be t' last flight for t' Mark 1X. Blimey! Blimey!

Here she is liftin' off on t' G80. Aye aye! Well, blow me down! This picture be takenÝ just as t' rocket cleared t' launch rod, arrr, and you can see t' fly away launch lug fallin' t' t' ground.

All exceptions are marked with an *

Component Notes:

Nose Cone - Public Missiles Ltd. Begad! Blimey! Part Number PML PNC-2.1. Avast! Blimey! Well, me hearties, blow me down! Blimey!

T' nose cone is a 9.5" long, tangent ogive. Begad! Blimey! T' original design used a 1.5" long elliptical nose cone. Ya scallywag! I had t' make t' nose cone out o' balsa wood, shiver me timbers, because no companies that I have found carry that shape. Ahoy! Avast, me proud beauty! I also made a fiberglass version o' t' nose cone by makin' a Plaster o' Paris mold o' t' balsa nose cone and layin' in glass. Avast!

Body Tube - Public Missiles Ltd. Well, blow me down! Part Number PML QT-2.1.

This rocket uses t' Public Missiles "Quantum Tube" which is a plastic o' some sort that makes the rocket a lot easier t' finish. Avast, me proud beauty! T' body tube is 30" long, with 5" long fin slots startin' 2.75" from the bottom. Public Missiles will cut and slot t' tubes for you at their shop. Begad! Aye aye! I highly recommend this service. There are four 3/32" fin slots. Begad! Arrr!

Fins* For me fins I used 3/32" acrylic sheet, but you can also use lexan (polycarbonate), ya bilge rat, or birch plywood. Arrr! Avast! Rough cut t' fins about 1/8"outside t' line, then glue them together and sand them down t' size. Aye aye! After they have been sanded t' t' proper size remove t' plastic film. This Rocket has 12 fins. Well, blow me down! Ahoy! From now on I will refer t' t' main fins as t' fins, t' front fins as t' canards, and t' aft fins as t' rudders. Ya scallywag! Ahoy!

Motor Mount - Public Missiles Ltd. Part Number PML MMT-1.5 x18. Well, me bucko, blow me down! Blimey!

T' motor mount is 18" long, me hearties, and unless you plan on flyin' this rocket a "J" motor, ya bilge rat, (in which case you might have a little trouble packin' t' parachute) cut t' tube t' 12" in length.

Centerin' Rings - Public Missiles Ltd. Avast! Part Number PML CR-2.1-1.5. Ya scallywag!

I used two, but if you want t' cut a groove in t' fin tabs you can use three. Ya scallywag!

Motor Adapter - Public Missiles Ltd. Aye aye! Part Number PML ADPTR-38/29. Blimey! Avast!

I plan t' use this rocket as me Level One Certification when I turn 18. Avast! Arrr! But until I am certified I will fly this on 29mm motors so I added a 29mm friction fit adapter. Blimey!

Motor Retention

Instead o' usin' several layers o' tape, I decided t' employ t' use o' a motor retention system. Avast, me proud beauty! But because of the limited space betwixt t' motor mount and t' body tube, arrr, me bucko, I had t' design a motor retention system myself. Ahoy! Kaplow Klips just wont fit. T' assembly o' t' retention system is detailed below. Avast!

System*

Parachute*

Public Missiles Ltd. sells a 48" rip stop nylon parachute, ya bilge rat, ya bilge rat, but I was unwillin' t' shell out another 25 bucks for it. Well, blow me down!

So I made me own! Blimey!

I bought 2 square yards o' camouflage rip stop cotton which I used in lieu o' nylon. Begad! For suspension lines I found a pack o' parachute cord which is 40' o' 1/16" braided nylon originally used for Army man-rated parachutes. Avast!

Ejection Gas Baffle*

Rather than shellin' out another 15 bucks t' buy a baffle I designed and built one me self, it also functions as the parachute mount. Its construction is detailed below.

Shock Cord*
For t' Shock Cord I used 2 yards o' t' same parachute cord I used for t' parachute suspension lines. Well, blow me down!

Airframe Assembly

Step 1: Draw lines on t' tube from t' slots t' t' front end o' t' tube, ya bilge rat, and t' t' aft end. Then prepare t' motor mount first by gluin' t' front centerin' rin' 1/8" from t' one o' t' ends o' t' tube with CA. Ahoy! Blimey! Well, blow me down! Blimey! After t' CA dries epoxy t' rin' in place. Ahoy! Blimey!

Step 2: Prepare t' second centerin' rin' by addin' t' motor retention system, (see below). Begad!

Step 3: Insert t' motor mount into t' body tube and position it so t' motor mount tube protrudes 1/16" from t' end o' t' body tube. Ahoy! Arrr! Dry fit t' rear-centerin' rin' on t' tube and mark t' motor mount for epoxy/ fin fillets by insertin' a pencil in t' slots and runnin' it back and forth. Well, blow me down!

Step 4: Cover t' pencil lines with epoxy and epoxy t' aft centerin' rin' º" from t' end of the tube. Avast, me proud beauty! Then insert t' motor mount 'til t' tube protruded 1/16" from t' end o' t' body tube.

Step 5: Place t' fins in their slots, and pressed them down until t' root edges contact t' body tube.

Step 6: After t' epoxy gels, matey, mask off t' body tube except for a º" on each side o' t' fins. Then add t' epoxy fillets t' t' fins. Arrr!

Step 7: Mask t' tube for t' fillets around t' canards and rudders, matey, ya bilge rat, then position and tack down the canards with CA. Avast, me proud beauty! Avast! Add epoxy fillets t' t' canards after t' CA dries. Begad! Arrr! (Bakin' Soda makes CA dry!!!, arrr, saved me nearly an hour.)

Step 8: After t' epoxy from t' canards gels, me hearties, arrr, position and tack down t' rudders with CA. After t' CA dries add epoxy fillets t' t' rudders. Avast, me proud beauty! Blimey! Arrr! Blimey!

Step 9: Filled t' gap betwixt t' motor mount and t' motor mount and t' body tube (think rear centerin' ring) with epoxy and let t' rocket sit for 24 hours for all o' t' epoxy t' cure. Arrr!

Step 10: Attach t' shock cord t' t' baffle then insert it into t' tube and epoxy it in place. Usin' a 10" piece o' 3/8" flat elastic tether t' nose cone t' t' parachute. Begad!

Step 11: I worked out a paint scheme and primed t' rocket. Avast, me proud beauty! After t' primer dried, I masked t' rocket and painted it. Ya scallywag! Begad!

Step 12: Sleep. Wake up in t' mornin' and admire a work o' art. Begad!

Motor Retention System and Assembly

In this rocket thar be about 6mm o' space on each side betwixt t' motor mount tube and t' body tube. Aye aye! Begad! No where near enough room for tee- nuts. Avast, arrr, me proud beauty! So I had t' come up with me own design. Avast!

Materials Notes

1/8" brass threaded rod -
I bought all materials from me local Home Depot. Aye aye! Blimey! Cut two 2" long pieces o' rod and sand or file a taper on one end, if you want a 4 post retainer cut 4 pieces. Begad! Blimey!

3/16" brass washers - You'll need 4 washers for two posts, arrr, matey, if you want a 4-post retainer you'll need 8.

1/8" brass nuts - You'll need 4 nuts, if you want a 4-post retainer you'll need 8.

º" wide brass strap - You'll need 2 each 1.5" long straps for a 2-post retainer, matey, me bucko, 4 for a 4 post version. Begad!

Step 1: T' threaded brass rod that I bought came in a 12" piece. Arrr! Ya scallywag! I cut two 2" pieces and sanded one end o' each t' a taper. Well, blow me down!

Step 2: I mixed a small batch o' epoxy and when it started t' gel, I dipped t' rough end 1/8" into the epoxy t' make a larger diameter shoulder. Well, blow me down! Ya scallywag!

Step 3: I drill two 9/64" holes 180 degrees apart and sanded t' edges o' t' holes. Ya scallywag! I'm only using two retainin' posts, put you can use 3 or 4. For 3 space t' holes 120 degrees apart. Avast, me proud beauty! For 4 space t' holes 90 degrees apart. Avast, me hearties, me proud beauty!

Step 4: I put t' two threaded rods through t' holes and covered t' area I didn't want epoxy t' get on with maskin' tape. Begad! After makin' sure t' rods lined up 90 degrees with t' centerin' rin' I epoxied them in place. Ahoy! If you are usin' a relatively thin epoxy it is a good idea t' let it almost gel before usin' it. It will be much thicker. Ahoy!

Step 5: Drill a 9/64" hole º" from t' end o' t' pieces o' strap, arrr, matey, me hearties, and de-burr t' hole. Aye aye! Ahoy!

Step 6: Put your motor into t' tube and mark off t' distance o' t' strap t' t' lip o' t' motor. (Or the point you want t' apply pressure t' with t' straps.)

Step 7: At t' mark bend t' strap so it forms a rounded o' 90 degrees angle. Begad! (In t' shape o' an L) Now round over t' strap where it will contact t' motor.

To use it first put t' motor in t' mount tube. Aye aye! Well, blow me down! Then thread one nut down just below t' level o' t' motor and put on one washer. Slide t' strap down, and then t' last washer and nut go on. Avast!

Excludin' drying/curin' time it takes less than 10 minutes t' make.

Ejection Gas Baffle Unit

Half t' fun o' buildin' rockets is designin' and buildin' all o' t' parts o' t' rocket. Arrr! Blimey! Blimey! Blimey! This Ejection baffle unit cost me less than $5.00 t' make. Begad! Blimey! Avast! Blimey! Blimey! Blimey!

Materials Notes

Bulkhead
My body tube was a 2.1" tube so t' bulkhead was pretty cheap. About $3.00. Ya scallywag! You may want t' epoxy coat the inside o' t' tube t' fire proof it.

Bulkhead plate with eyebolt
Screw t' eyebolt all t' way down and epoxy it in place. Ahoy! You might need t' widen t' hole so you don't have any tear out.

Centerin' ring
T' rin' should fit your body tube but have a hole in t' middle 1 size smaller than t' motor mount you are using.

1-2 square feet o' screen
Cut a circle slightly larger than t' diameter o' t' hole in t' centerin' ring. Save t' rest for t' baffle medium. Ahoy! Arrr!

Step 1: Drill a circle o' holes around t' center hole in t' bulkhead plate and sand t' edges o' the holes. About 1/8"- 1/4" should be right. Ahoy!

Step 2: If necessary widen t' hole in t' middle and screw t' eyebolt all t' way down. Avast, me proud beauty! Epoxy the eyebolt in place on both sides o' t' plate and make sure t' get a good bit o' epoxy in t' open loop o' t' eyebolt. Ya scallywag! Avast, me proud beauty!

Step 3: Cut t' bulkhead tube about 3 *" long. Insert t' bulkhead plate in about *" and epoxy it in place on both sides. Begad! Ya scallywag!

Step 4: cut a circle o' screen slightly larger in diameter than t' hole in t' centerin' ring. Begad! Put a rin' o' epoxy around t' hole in t' centerin' ring. When t' epoxy is just startin' t' gel press t' screen down in to it. Begad! Begad! Waitin' will save you a lot o' effort. Well, blow me down!

Step 5: Look at t' rocket and admire what you've done so far. Avast, me proud beauty!

Step 6: After t' epoxy has gelled enough t' make it hard t' t' touch, wad up t' rest o' t' screen and push it into t' bulkhead. Begad! Do nay stuff t' bulkhead t' full. Begad!

Step 7: Epoxy t' centerin' rin' onto t' bulkhead plate. T' outer diameter o' t' rin' should match the outer diameter o' t' tube. Arrr! Blimey!

Step 8: After all o' t' epoxy has cured, ya bilge rat, me hearties, tie your shock cord t' t' eyebolt. Begad! Well, shiver me timbers, blow me down! With a stick put a layer of epoxy inside t' body tube about *" from where t' baffle will rest. Well, blow me down! Insert t' baffle into t' tube and press it down until it contacts t' motor mount tube. Blimey!

Launch Report

After finally gettin' everythin' ready t' go with t' rocket I realized I had forgotten t' build t' launch tower that I be goin' t' use rather than usin' launch lugs. Ya scallywag! Aye aye! So I cut a piece o' sheet tin t' about 4" wide and about 2" longer than t' circumference o' t' tube and made a "fly away launchÝlug" like t' one on Bob Fortunes page. Ya scallywag! After pickin' up a friend, arrr, and stoppin' t' get some fast film, we drove straight east o' Denver for about an hour and a half until we found a nice open spaceÝwith no fences. We walked out into t' t' field and set up pad. Begad! Begad! I loaded t' first motor into t' rocket. It was an Aerotech F25-6 white lightening. While rocksim predicted t' rocket would fly t' about 1102', t' rocket had a very curved flight, and flew in a large arc, and only achieved an altitude o' about 800'. T' rocket be recovered about 100 yards fromt t' pad. T' fly away launch lug worked perfectly and released from t' rocket about 2-4 feet off t' rod.

T' second flight took off on an Aerotech G80-10 blue thunder, and lifted off extremely fast and extreemly straight. Avast! After burn out t' rocket started t' coast a little off coarse. Begad! T' ejection charge fired perfectly at apoge, which although Rocksim only predicted an altitude o' 1970 feet was about 2200 feet, shiver me timbers, t' parachute was ejected way too violently and zippered t' tube about 12 inches. T' over-powered ejectioncharge also blew out t' motor retainer and adapter, and pushed t' entire (epoxied in) motor tube and baffle units about 8" up into t' tube. T' parachute lines tangled in t' torn tube and t' rocket free fell from about 2200 feet. Arrr! Aye aye! When recovered, me bucko, me bucko, t' rocket was in severe condition. Aye aye! It lost all o' its fins except t' main fins, ya bilge rat, which wereÝfiberglassed t' t' tube. Begad! T' fall had even broken t' fiberglass seem.

Well, one more rocket t' add t' t' collection.