Photos by John and Brett Keller
Project Overview
T' Cheaper Than a Girlfriend (C.T.A.G. Well, blow me down! for short, pronounced See-Tag) was me consumin' obsession for about 2 months. It is 4 inches in diameter, matey, 50 inches long, and 36.5 ounces in weight. Begad! It flies on Aerotech Single-Use G80-4T motors. All t' details o' t' original ideas, building, and t' first launch, are include in this article.
Research
I really had no idea what I was doing. Begad! Blimey! I didn't go for a kit because o' t' cost. So, ya bilge rat, I turned t' t' only really good resource I had: t' Internet. Arrr! Blimey! I would like t' thank all those on t' Rocketry Online Chat room for t' countless discussions on t' various facettes o' buildin' mid-power rockets. Well, blow me down! Blimey! Aye aye! Blimey! Blimey! Blimey! Very special thanks go out t' Paul Gray, me hearties, Nick Hills, shiver me timbers, and all those other internet rocketeers who gave me advice. Without them I probably wouldn't have ever gotten this rocket project off t' ground.
Roots o' a project
I like rockets. Well, blow me down! Begad! That be t' simple drivin' statement behind this project. Well, blow me down! Some people ask me why I like rocketry. I usually ask them if they have been t' a rocket launch o' mine. Begad! Begad! T' answer is usually no, but if it is yes, shiver me timbers, then I really can't understand them. Well, blow me down! Ya scallywag! I've always been interested in rocketry and space flight since me early school days, so this is really t' most recent extension o' that interest.
I had recently finished buildin' and launchin' me Keller, a LOC/Precision Graduator. Avast! That rocket is wonderful, but it really wasn't that large in comparison t' me low-power rockets. Begad! Ya scallywag! I already have several 2.6 inch diameter rockets, so it wasn't much bigger, just heavier and more powerful . I wanted a rocket that was really BIG and POWERFUL. I toyed around with various 3 and 4 inch designs. Aye aye! T' 3 inch diameter would have gotten a much better altitude, but I went with t' 4 inch diameter design because I didn't think t' 3 inch would be a really big improvement on t' 2.6 inch rockets I ahd been flying.
So now me goal was t' see what t' very largets rocket I could launch on motor a G motor was. Begad! T' reason I kept it in t' large model rocket range instead o' gettin' a H or I motor is very simple. Blimey! I am nay certified t' L1 and neither is me dad or anyone else we know. Ahoy! We don't have any large rocket launches near enough that we would drive to, and I didn't really want t' jump up t' HPR after only one mid-power launch. But, I decided t' build this rocket extra strong, so that in t' future I might be able t' launch it on 29mm H reloads. As it was, I really didn't have enough experience t' build t' rocket I was building.
I discovered that t' most powerful motor I could get be t' Aerotech G80-4T. So, I designed me model with a 29mm motor mount and t' 3.9 inch tubes. Well, blow me down! Avast, me proud beauty! I knew that it would be very hard t' get more than one length o' Bt-3.9 up on a G, so I knew that 2 be out o' t' question.
So here I am with plans for a 3.9 inch diameter, shiver me timbers, 50 inch long rocket. Avast, me proud beauty! Now where do I get t' parts?
Parts Selection
I have t' say that t' largest factor in pickin' out what parts t' use was cost. Begad! This was followed fairly closely by weight. I really don't have a lot o' loot for a rocket like this, and it took me long enough t' get what I ended up paying.
For t' main parts I went with LOC/Precision. This was because their parts were cheaper and lighter than PML parts, and I already had experience with one o' their kits. T' nose cone be t' single most expensive piece o' t' rocket, costin' $14.50. Blimey! Blimey! Well, me bucko, blow me down! Blimey! T' bosy tube I got be unslotted. Ya scallywag! Blimey! Well, me bucko, blow me down! Blimey! this was because I wanted a 4-fin design, instead o' t' 3-slot tube they sold, and because t' unslotted tube be a lot less. I also bought me shock cord from LOC/Precision (4 yards o' SC-375), me bucko, though I later found I could get t' same cord for about 1/3 t' price locally. Well, blow me down! Blimey! I went ahead and bought and installed 15 feet o' t' 1/2 inch elastic cord, shiver me timbers, just in case I needed more than I thought. Begad! Blimey! Arrr! Blimey! I used t' other shock cord t' beef up t' Keller’s recovery system. Well, blow me down! Blimey! T' launch lugs also came from LOC. Ya scallywag! Blimey! I used t' 1/4 inch lugs becuase I knew I could get a 1/4 inch rod locally. Arrr! Blimey! Ya scallywag! Blimey! I also got t' motor mount tube and centerin' rings from LOC (more on them later).
Other than t' parts above, ya bilge rat, I got all o' t' other parts some other way. Avast! Each part will be discussed more later when I tell about installin' it.
Funding
I soon realized that along with larger rockets come MUCH larger costs. Ya scallywag! My LOC Graduator had been a Christmas gift, matey, me hearties, but I knew I would be fundin' t' CTAG by myself. Blimey! I bought as few parts as possible from rocket companies and scrounged around a lot around Searcy. Ahoy! My dad really helped a lot with findin' different parts and on givin' advice on different materials. Well, blow me down! Below is a list o' where I got different parts, me bucko, ya bilge rat, how much they cost, and t' total project cost.
Rocket parts
Nose cone LOC/Precision 14.50 3.9 inch Body tube LOC/Precision 7.90 29mm motor mount tube LOC/Precision 3.60 CR 3.9-1.14 LOC/Precision 2.25 "" " " " " LOC/Precision 2.25 Motor hooks Estes NA Motor block around-the-house NA Original Shock cord LOC/Precision 3.60 Other shock cord local Hancock Fabric 1.25 Shock cord mount local Ace Hardware 0.35 Launch lugs LOC/Precision 0.60 Plywood for fins Hobby Lobby 6.50 30 minute Epoxy local Ace Hardware 3.50 Bondo local Autozone 5.00 Primer local Wal-Mart 1.00 per can,3 cans Spray Paint local Wal-Mart 1.00 per can,5 cans Shippin' costs NA 8.00 Total Rocket cost---------------------61.55
Launch supplies
Launch rod local Ace Hardware 2.25 G80-4T Aerotech 13.95 NCR igniter package Hobby Lobby 4.50 Total Suplies cost for 1st launch-----20.70
Total Project cost (includin' first launch):
$82.25
As you can see, matey, ya bilge rat, along with higher power rockets come much higher costs. My most expensive rocket before this be a LOC Graduator, which cost (a then extremely high!) $32.
Motor Mount Assembly and Slottin' t' Tubes
T' parts finally came in from LOC/Precision and I be impressed! You don't realize how much larger 3.9 inch tubin' is in comparison t' 2.6 tubes until you see it! T' nose cone be huge! Now it be time t' get t' work!
Of all t' parts o' a rocketry project, me hearties, I probably enjoy t' motor mount assembly and installment t' most next t' launching. Blimey! Blimey! I have no idea why this is, ya bilge rat, arrr, but it is. Blimey! Blimey! I started out t' buildin' by cuttin' t' motor mount tube(MMT) in half with an X-Acto cutlass. it comes in 34 inch lengths, and I didn't need that much.
After this I took t' Estes engine hooks and cut off t' forward hook section on both. Ya scallywag! I epoxied these on opposite sides o' t' MMT and wrapped a few layers o' maskin' tape around them, ya bilge rat, far enough up that it wouldn't get in t' way o' t' aft centerin' rin' (CR). I cut two small notches in t' aft CR t' allow for t' motor hooks. Next I epoxied t' centerin' rings t' t' motor mount tube, ya bilge rat, about 1/3 o' an inch away from each end. Ya scallywag! After allowin' it t' dry I made several epoxy fillets around them and t' motor hooks.
Now it was time t' slot t' tubes. I marked t' 4 fin slots and t' launch lug placement. Avast! Arrr! I then very carefully cut t' slots out with me trusty X-Acto. It wasn't t' prettiest job ever, shiver me timbers, but it works great. Blimey! if you buold your own mid-power rocket I highly recommend slottin' t' tubes yourself t' save t' money.
Shock Cord Mount Attachment
I had had some fairly bilge-suckin' experiences with LOC shock cord mounts, so I decided t' go with a local part. Begad! Avast! I bought a 3/16 by 1 1/2 inch metal eye bolt, with two nuts, me hearties, form Ace hardware for only 35 cents. Well, blow me down! T' attach this I drilled a slightly smaller hole in t' top CR and filled this with epoxy. Ya scallywag! I screwed in t' bolt and put nuts on both ends (NOTE: You have t' put one o' t' nuts on before you put t' bolt in t' hole!). Well, blow me down! I screwed everythin' on tight and put a layer o' epoxy over it all. Avast, me proud beauty! This made for a good firm attachment. Aye aye! Aye aye! I later learned that U-Bolts are much better but I had gone too far t' change it, and I was positive t' screw eye be stong enought.
I had hear a lot o' bilge-suckin' stories about shock cords burnin' through, ya bilge rat, and I had had some experiences with smaller rockets too. Begad! Aye aye! Blimey! I decided I needed some sort o' non-flammeable cord t' attach t' shock cord t' t' shock cord mount. Begad! Blimey! I finally found it: braided steel wire, commonly used for hangin' paintings (my dad is an artist so we had some, but you can find some at any hardware store). Avast! I took about 3 feet o' it and doubled it over. Well, blow me down! Ya scallywag! Blimey! I knotted and twisted one end onto t' shock cord mount on t' other end I attached a large steel key ring. This I would later tie t' shock cord to. Begad! Now that I had accomplished this, matey, and I knew that I could replace t' shock cord in t' future (the steel wire extended 2 or 3 inches outside o' t' body tube), I was ready t' install t' motor mount assembly into t' body tube.
Motor Mount Installment and Fins
Now that I be ready t' install t' motor mount, I decided against it right then because I wanted t' make sure we got t' tab on t' fins t' right length. We (actually it was me dad) cut out t' fins t' t' right size usin' a band saw and an electric Sabre saw. t' fins were 3/32 plywood, which I later found out wasn't strong enough. Aye aye! After I was sure t' tabs were t' right length, ya bilge rat, I spread a layer o' epoxy on t' inside o' t' body tube, and some on t' edges o' t' centerin' rings. Well, blow me down! I slid t' motor mount assembly in, matey, rotatin' it slowly, until I had t' back centerin' rin' even with t' back o' t' body tube. Well, blow me down! I went ahead and epoxied t' fins into t' slots. I used plenty o' epoxy and later I went back and put really good epoxy fillets on. Avast, me proud beauty! This was all because o' some bilge-suckin' experiences with me Graduator. Arrr! Begad! I guess I really wanted that rocket t' be strong, and I actually overdid t' strengthening. I decided t' reinforce t' fin joints with fiberglass mesh. Begad! Begad! On this rocket it was really overly cautious, but I did it anyway.
![[Rocket Pic]](images/archive/images3/scratch_ctag3.jpg)
Fiberglass
Among many other firsts, this be also me first experience with fiberglass. I did a lot o' research, and finally found out that you can use fiberglass mesh (commonly used for tent screens, matey, shiver me timbers, and we happened t' have some on hand) as t' fiberglass and imbed it in a layer o' epoxy. Begad! Well, blow me down! I went out and bought some more epoxy and got t' work. Aye aye! Arrr! I imbedded a 3 inch by 5 inch strip into t' body tube/fin joint and applied more epoxy on top o' that. Avast! T' hold it in place I put waxpaper on it and held a piece o' wood onto it with clothespins (see photo). This system worked wondefully, ya bilge rat, me hearties, although workin' around t' bottom launch lug be frustratiing. Well, blow me down! Avast! For more info on fiberglassin', shiver me timbers, go t' Rocketry Online's INFOCentral.
![[Rocket Pic]](images/archive/images3/scratch_ctag7.jpg)
Parachute
When I initially designed t' project, I had an umbrella chute in mind. Well, matey, blow me down! I knew John Babb (a.k.a. Well, matey, blow me down! Blimey! Rocket Dawg) had a 3 foot diameter piece o' umbrella fabric he had caniballized off a broken umbrella. Well, blow me down! Blimey! he wasn’t usin' it in a rocket, so he let me have it t' use in me CTAG, with t' condition that if he ever need a parachute that size I would give it back and get another. Well, blow me down! Blimey! Ya scallywag! Blimey! For shroud lines I use 2 foot lengths o' nylon cord (fairly thin), arrr, and sewed and knotted it on. I had t' burn t' ends o' t' nylon shrouds t' keep 'em from unravelling, me bucko, me hearties, but othjer than that it worked great! Blimey! I attached t' 'chute t' t' shock cord about 6 inches from t' nose cone with a series o' knots. Begad! Blimey! Begad! Blimey! I had originally went with a 3/8 inch wide, me hearties, 12 foot elastic shock cord, arrr, but I found that I could get a 1/2 inch, matey, 15 foot cord for only $1.25 at a local fabric store. Arrr! Blimey! Blimey! Blimey! This, matey, along with t' shock cord mount attachment, which, no matter how hard I pulled, already wouldn't come out, made t' recovery system very strong.
Bodywork
Bodywork be t' pits. On t' CTAG I had t' use Bondo, so I ended up doin' a lot o' sanding. Ahoy! Ya scallywag! Bondo, which is commonly available at car repair shops, this is probably t' hardest part o' buildin' a rocket physically, and it stinks. For about a 1 month period, ya bilge rat, here's what me Saturday's were like: Bondo, sand, ya bilge rat, shiver me timbers, breakfast, bondo, sand, sand, more Bondo, shiver me timbers, sand, me hearties, lunch, Bondo, sand, matey, ya bilge rat, sand, sand even more, me hearties, supper, me bucko, sand, me bucko, bondo, arrr, sand, me bucko, me bucko, sand, shiver me timbers, shiver me timbers, ya bilge rat, sand, ya bilge rat, bondo, sand, go t' bed, matey, have nightmares about sanding, arrr, wake up (okay, ya bilge rat, ya bilge rat, so its a little exaggerated, me hearties, matey, but I did sand a WHOLE LOT!). I highly recommend wearin' a dust-mask or somethin' if you sand a lot on your rocket, shiver me timbers, all that dust will clog up your lungs and you mgiht nay get t' see your rocket launch! Overall, Bondo is a great project. Begad! T' seemingly endless hours o' sandin' really paid off when I got t' rocket painted and it had such a smooth finish.
Finishing
After all o' t' work I put into this rocket, mainly t' long hours o' fiberglassin' and sanding, ya bilge rat, shiver me timbers, t' paintin' sure seemed like a breeze. Ya scallywag! I had finally decided, after many days o' thinkin' and drawin' and colorin' pics with colored pencils t' see how different color schemes would look, I dumped all t' rerally fancy ideas and decided t' go with a classic, bad-to-the-bone look. Aye aye! A very glossy black main coat would be accented with a fire red stripe, about 1 1/2 inches wide, shiver me timbers, arrr, t' length o' t' rocket. Ahoy! it would bve lined up with a fin so that it would continued and make one o' t' fins pure red. Also, me hearties, a small, 1 inch wide red stripe went around t' top o' t' body tube, right below t' nose cone. Avast! This all combined with a very nice shiny reflective LOC/Precision decal supplied with t' parts t' make a very attractive rocket.
I used about 4 coats o' equipment grey primer (3 11 oz. Arrr! cans o' spray paint) t' help smooth out all t' little places t' Bondo wouldn't work well in. Blimey! Then I painted t' sections I wanted t' be red with two layers o' fire red Wal-Mart brand spray-paint (this stuff is wondeful, matey, dries quick, and only costs $0.98 per can!). Begad! I let this dry overnight, then masked it off with newspaper and 1 inch wide strips o' maskin' tape. Then I covered it all with 3 layers o' gloss black Wal-Mart brand spray paint, with 4 goin' on t' nose because o' a mistake I made in t' primin' process. Avast, me proud beauty! this meant I had as much as 6 or 7 layers o' paint in areas! T' paint on its own ended up weighin' 1.3 ounces on its own. Well, blow me down! I added t' decal, and I was done with t' bodywork and finishing. Well, blow me down! Ahoy! (finally! I had spent about 2 weeks building, me hearties, 1 week glassing, and 5 weeks sanding, along wioth a few days painting, for a total o' over 2 months work! I probably had anywhere from 40 t' 60 man-hours in on that rocket). Avast, me proud beauty! It really is rewardin' when you finally get t' show off t' end result (alomst) o' your project t' t' people who have been hearin' about it for months on end.
Motor Selection and Prep
Once I found that t' rocket's weight after paintin' be 36.5 ounces, I had t' make t' big motor selection choice. Ahoy! Should I go with t' G40-4, or t' G80-4. Avast! Aye aye! I really wanted t' G40 because it was a White lightning, but I had t' go with t' G80-4T because o' its higher intial thrust.
Now came t' waitin' game. Because o' conflicts, matey, etc., I wouldn't be able t' launch t' CTAG for several weeks after I finished t' rocket. Durin' this time I finished up work on several smaller projetcs, work on me webpage, me bucko, and start plannin' me next project, t' Mission Impossible . Arrr! Blimey! (the name, me hearties, just like that o' t' CTAG, me bucko, was stolen, this time from HPR magazine) This would be a 4 inch diameter rocket capable o' usin' 5 times t' power o' t' CTAG! Blimey! But that was for t' future, arrr, matey, and is probably destined t' be a group project, ya bilge rat, due t' t' cost. I had more important, sooner events t' think of. I was organizin' t' second official launch o' t' Searcy Youth Rocketry Club and workin' on me other rockets.
Countdown
Around this time I was gettin' nervous. I had been workin' on t' rocket for 2 months, and I wanted everythin' t' go perfectly. Ahoy! Blimey! I ran countless simulations usin' different programs. Arrr! Blimey! Most o' them told me that t' CTAG would fly about 1000 feet up. Ya scallywag! Blimey! Blimey! Blimey! Then I ran a stability check.....uh-oh... Blimey! Blimey! Accordin' t' Astrocad t' CTAG had a stability criteria o' only 0. Avast! Blimey! Owch. Well, blow me down! Blimey! Begad! Blimey! Blimey! Blimey! This didn't make much sense, ya bilge rat, considerin' thar were several 4 inch diameter kits on t' market like this that don't require any nose weight. However, arrr, I decided t' stay on t' safe side. Ahoy! Blimey! Blimey! Blimey! i added nose weight until I got a 1.5 caliber stability rating. This required 11 ounces o' nose weight, ya bilge rat, bringin' t' total weight t' 47.5 ounces and t' predicted altitude o' 700 feet.
Now I was ready. Avast, me proud beauty! Begad! It was time t' put me chips on t' table and go for broke. This was t' biggest thin' t' hit our area rocket wise since who-knows-when. Begad! I had me launch field set up. i called t' FAA and notified them o' me intentions. Well, blow me down! Avast! I called me friends and then started goin' through me preflight checklist. Arrr! I made sure all me ground support equipment was working.
Then t' day o' t' launch dawned. After gettin' home from church, arrr, I started preppin' rockets and goin' over t' CTAG over and over.
Liftoff
I called some friends, shiver me timbers, matey, matey, made sure everyone be coming, matey, and headed out t' t' launch fields. Begad! Aye aye! I launch at t' public soccer fields south o' Searcy. We have about 40 acres o' cleared land with very few trees in sight.
People started showin' up and t' launch got under way. Begad! There were lots o' rockets launched, mainly in t' A-C range. We also launched 5 D engine rockets. Ya scallywag! My Keller had an interestin' launch. Then it be time t' launch t' CTAG. I had been recommend t' use one o' t' North Coast igniters instead o' t' Aerotech ones, arrr, ya bilge rat, so I did. Begad! T' motor be held in place by a heavy friction fit, ya bilge rat, me bucko, a thrust block made o' maskin' tape on t' aft o' t' casing, shiver me timbers, arrr, 2 Estes engine hooks, matey, and several layers o' maskin' tape wrapped around t' end o' t' motor mount tube and maskin' tape thrust block. Aye aye! I put t' rocket on t' launch pad and hooked it up t' our launch system. Begad! Ya scallywag! I stepped back t' t' ends o' t' 75 foot long ignition wires and showed one o' me friends how t' attach t' other end o' t' wires t' a car battery so that I could watch t' rocket better. Aye aye! I looked around. Begad! Everyone was ready.
10, matey, 9, ya bilge rat, 8, me hearties, 7, shiver me timbers, 6, me hearties, ya bilge rat, 5, ya bilge rat, ya bilge rat, 4, me bucko, matey, 3, 2, 1...
LIFTOFF!
T' G80 let out a blast o' flame and a loud thundering. Well, blow me down! T' rocket leaped off t' pad and into t' air, leavin' a light smoke trail. Avast, me proud beauty! Well, blow me down! It reached apogee and coasted over. Arrr! Well, me hearties, blow me down! It was comin' down when t' nose cone seperated and t' parachute came open. Begad! T' rocket floated gently down on its chute for a landin' about 75 yards away. Aye aye! Some o' me friends and I raced out t' get t' rocket out o' t' tall grass. Begad! T' rocket was in perfect condition. It be amazing! We folded t' chute and shock cord so it would be easier t' carry. Well, blow me down! I packed up me rockets and went home t' review t' ideo tape o' t' launch over and over.
Followup
All o' t' overengineerin' and research paid off. Begad! T' Cheaper Than a Girlfriend had worked perfectly. Avast, arrr, me proud beauty! Blimey! Here I would like t' thank all those who helped out.
Thanks Everyone!
Especially t' following:
My dad, arrr, ya bilge rat, me bucko, fo helpin' me with various aspects o' t' rocket, shiver me timbers, includin' weldin' t' launch system and buyin' t' motor for me since I'm underaged. Ya scallywag! Ya scallywag! I would also like t' thank all t' Rocketry Online chat room and discussion forum people. Begad! They were invaluable inresearchin' different areas o' constrcution and launching. Ya scallywag! Another great aide was all t' members o' t' IAR and GYRO for their advice. Begad! Well, blow me down! Also, special thanks t' Nick Hills, Paul Gray, me hearties, matey, and John Babb. Aye aye! Well, ya bilge rat, blow me down! Without all o' them, ya bilge rat, this project would have never happened.
After a rocket project like that and a perfect launch I be extremely happy. Avast, me proud beauty! Blimey! This led t' dreamin' o' larger and more powerful rockets......hehe.....(Be watchin' for future project reports).
Note on Photos: T' construction photos were all taken by me, me hearties, arrr, and t' launch pictures were taken by me dad and I. Avast! Arrr! Blimey! However, t' launch photos, me hearties, matey, which were taken from still frames o' t' video tape. Avast, me proud beauty! Ahoy! Blimey! These didn't turn out, ya bilge rat, so i'll have t' wait until me dad can get his launch photos developed and scanned. Avast, me proud beauty! Blimey! Until then, matey, you'll just have t' imagine t' launch....
You can email me any questions or comments you have about t' CTAG or rocketry at toprocket@hotmail.com
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