Brief:
Single stage Centuri Classic circa '73 - '81. Ahoy! Upscaled for 24mm motor C & D.

Construction:
Stats Original Upscale:

• Length 18 in 23.4 in
• Diameter (Inside) 1 in 1.3
• Fin Root L 2 7/16 3 1/8
• Fin Topline Length 2.25 3 in (close enough)
• Fin Trailin' Length 2 in 2 19/32nd
• Vane Width 3/8 in ½ in
• Vane Length 7.75 in 10 1/16th
• Nose Cone L 5 inch 6.4 inch (6.5 scale)
• Body Tube L 13 inch 17 inch (16.9 scale)
• Engine Mount 18 mm 24 mm

Parts list:

• Body Tube ST-13 17 inch
• Nose Cone BNC1364 6.4 inch
• Engine tube BT-50 2.75 inch
• Centerin' Rings CR5055 Fiber
• Tube Coupler c55 2 inch
• Engine Hook standard 2.75
• Fin Stock (3 Fin) 3/32 basswood
• Vane Stock (3 Vanes) 1/16 basswood
• Tether 400lb Keelhaul®©™® 24”
• Shock Cord ¼ inch Sewin' Elastic 30”
• Metallic Bands ½ inch shiny gift wrap bow
• 15 " Ripstop Parachute with lockin' Snapswivel

T' upscale called for a body tube length o' 16.9 inch and a nosecone of 6.5 inches. Well, blow me down! I chose t' BNC-1364 for its length at 6.4 inch. Begad! Well, blow me down! Although it was not t' right shape, shiver me timbers, matey, it was reasonable t' add 1/10th inch t' tube length to keep length t' scale. Arrr! A closer shape match would have been t' pointy BNC-1353 Secant Ogive, matey, but addin' 1.2 inches more tube might have changed t' look too radically.

Parts supplied by SEMROC. Parachute home made (another review maybe?)

Building

Scalin' this rocket should have been easy, shiver me timbers, rotate t' kit templates, shiver me timbers, print to 130% scale on printer and cut. Avast! Aye aye! But somethin' didn’t look right. When I printed it up, me bucko, t' vanes were too short. Luckily I had t' original Kit to measure against. Ahoy! T' drawn Fiber fin template in posted plans measure in at 7 17/32 . Begad! Ahoy! T' actual kit measures 7 ¾, matey, ya bilge rat, callin' for 10.075 inch upscale length. Blimey! I cut t' vanes t' 10 and 1/16th inches, ya bilge rat, matey, scale t' me original Nomad Kit. Begad! Vane width on t' kit was approx 11/32 finished. Blimey! I chose t' use ½ inch width 1/16th thick basswood, me hearties, me bucko, available from me local craft store AC Moore. After trimmin' t' scale, ya bilge rat, I rounded t' edges removin' about 1/16th inch. Begad!

I tested t' scale o' t' printed template for t' fins against the original model and they were on t' money. Blimey! They were printed at 130% and cut from 3/32 basswood. I tried usin' 1/16th basswood for t' fins, me bucko, but they just didn’t feel sturdy enough. Ahoy! Rather than riskin' fin flutter or shearing, me hearties, ya bilge rat, I went with t' 3/32 stock. This also provided a stronger joint with t' glue rivet method.

Templates

After markin' up t' body tube with a standard fin markin' guide, shiver me timbers, matey, I drew the lines for 3 fin and vane alignment, addin' a mark for lug mounts centered between two o' t' vanes. I also measured up from t' aft end a position around t' tube for t' aft end o' t' vanes. Blimey! This measurement be attained by measurin' t' fin root o' 3 1/8 inch and addin' another 1/3 inch for spacing, up from ¼ inch on t' original. Ahoy!

With t' tube marked, I printed out 3 Centuri Fin Guides on heavy stock 5x7 index cards. I cut out t' size 13 center and cut out t' fin guides t' ½ inch length. Begad! Ahoy! I pushed t' fin guides along t' length o' t' body tube spaced about 4, shiver me timbers, 8 and 12 inches from t' aft o' t' tube. Blimey! Aye aye! I set t' vanes against the body tube with three fin guides supportin' along t' length o' t' vane and tacked t' position with C/A near t' fin guides. T' tube was laid on its side with t' index cards supportin' it on a flat surface. Well, blow me down! They set perfectly and were next treated t' Elmer’s Pro-bond, shiver me timbers, a thin fillet pressed into the joint with a finger pass. Arrr! Arrr! Do nay use t' super glue at t' front or rear contact points as these points have t' highest shearin' stress. T' vanes were not riveted because I be goin' t' install a baffle ejection. As it turned out I did nay use t' baffle. Arrr! A few launches will judge this decision. Avast, me proud beauty! When the vanes were absolutely dry and set, arrr, me hearties, they were sanded by hand t' bevel/round the edges. Aye aye! A small strip o' sandpaper pinched betwixt t' thumb and forefinger drawn along t' vane length makes a great bevel on this thin stock.

Engine Mount

This be fun as I had t' improvise a little. Begad! I built t' mount in a 2 inch section o' C55 coupler tubing. Arrr! I know its nay t' same diameter, but I have tons o' CR5055 and this tubin' worked well with it. Aye aye! T' Bt-50 engine tube was used with a thrust ring, engine hook and Keelhaul®©™® tether attached, shiver me timbers, mounted in t' forward centerin' ring. Aye aye! Arrr! T' coupler stock was glued t' t' other CR and allowed t' dry. Avast! After drying, ya bilge rat, t' CR was notched to accommodate t' engine hook. Avast! All interior joints were reinforced liberally with Pro-bond. Avast! When glued together, they made a nice mount, albeit a little narrow in diameter. Begad! Ahoy! This be solved by usin' an index card as a shim, me bucko, glued inside of the aft o' t' ST-13 body tube. Arrr! Begad! One wrap around gave a perfect fit for the mount assembly, shiver me timbers, which was glued just past flush, ya bilge rat, t' allow for t' engine hook retracting. T' engine hook be set directly opposite t' launch lug alignment line. Begad! (Say that five times fast!!!)

Fin Prep and Mounting

T' basswood fins were exceptionally smooth after a few passes with 150 grit sandpaper. Arrr! Avast! I used me rotary tool ($9 attachment piece designed for mower blade sharpening) t' bevel t' outside edges t' 45 degrees. Arrr! Well, blow me down! Very quick work with t' small drum sander bit.

Usin' t' rotary tool, matey, with another o' t' over a zillion pointy bits available, me bucko, matey, I made 1/16 rivet holes slightly staggered along t' fin guide lines. Blimey! These holes went through t' engine mount as well. With t' tool out and buzzing, I made rivet holes for t' Launch Lug standoff mounts ½ inch long startin' at 6 ¼ inch and 10 ½ inches from t' aft body tube. The mounts were scaled t' their template at ¼ inch high ½ inch long and cut from 3/32 basswood with t' grain aligned parallel t' t' leadin' edge. Begad! Avast! The fins and mounts were glued on and set with t' help o' another fin guide, shiver me timbers, cut to accommodate them. Begad! Ahoy! A light brushin' with thinned Elmer’s white glue gave a smooth workeable surface, prepared for finishin' with a light sanding. Ya scallywag! Two ½ inch Launch lugs were trapezoid cut, ya bilge rat, sanded along their mountin' line and glued flush with t' leadin' edge o' t' standoff mounts with Pro-bond.

Nosecone

Every time I grudgingly have t' wait for somethin' t' dry, matey, I remember I have a nosecone t' finish. Ahoy! T' BNC-1364 was smooth and clean, ya bilge rat, but I debated sandin' t' tip t' a narrow point t' match t' original. Begad! Well, blow me down! Close enough won out and I started with a liberal brushin' o' wood hardener. Begad! Blimey! After lettin' it dry for two days over t' boiler, I sanded off a few excess resin beads and gave it a wood filler rub. Another light sandin' with 220 grit and it be ready for a diluted Elmer’s over-coating. Avast, me proud beauty! This really bonds t' filler and leaves a liquid smooth finish. Well, blow me down! By t' time I am ready t' give it a last sanding, the final fillets were dryin' on t' vanes and fins and t' project is about complete.

Finishing

This usually takes months, me hearties, only because I usually start another project first. Ya scallywag! This time I had a forecast o' 50 degree weather (in t' middle of January?), so I was motivated t' git’er done. Begad! Test fits and CG/CP confirmation, I was ready for paint. Avast! T' quality o' t' body tube eliminated the need for tedious spiral filling, so t' first light coat o' Krylon white primer was without blemish. A few glue marks were noted and promptly ground or sanded away. Aye aye! Ahoy! Krylon Gloss White went on smooth and light for three coats. Ya scallywag! I coated each third o' t' project horizontally from t' top, with one fin pointin' down. Aye aye! Any overspray would gather in t' fin and vane fillets, giving it that “dipped” look. Aye aye!

Chromed bands and Specifications Plate

T' Decalin' was pretty straightforward. Avast, me proud beauty! Blimey! Ahoy! Blimey! I had originally wanted t' build a 1:1 clone so I had redrawn t' NOMAD decals long before I bought t' ST-13 tube. Avast! Blimey! Ya scallywag! Blimey! Based upon t' scans in t' online plans, ya bilge rat, me hearties, I used MSPaint t' straighten, refine and clarify some o' t' details. Begad! Blimey! Well, blow me down! Blimey! It came out remarkably good, arrr, shiver me timbers, even perfect when viewed enlarged. Some cuttin' and pastin' would fit t' decals on one sheet o' 8x11 Bel inkjet paper. Well, blow me down! Blimey! Ya scallywag! Blimey! T' chrome metallic bans that encircle the tube and vanes at t' standoff mounts were too cool t' nay include. Avast! Blimey! Aye aye! Blimey! After searchin' for materials t' use, shiver me timbers, I settled on a large chrome look gift-wrap bow. It be ¾ inch wide with paper backin' and did nay react adversely t' clear acrylic gloss spray. Begad! Blimey! I trimmed it down t' ½ inch t' match t' standoff mounts and used brush on C/A one section at a time. Well, blow me down! Blimey! I used painters tape below the final position t' mark t' line, me hearties, me hearties, matey, only you have t' remove it as you affix the ribbon or t' c/a might set t' tape as well. Avast, me proud beauty! Blimey! Begad! Blimey! Pressin' t' ribbon t' the tube as you go around will assure a good set. Ahoy! Blimey! Ya scallywag! Blimey! As it happens, a full length of ribbon (separated by staple marks from its bow shape) made it around t' tube and vanes. Well, blow me down! Blimey! Aye aye! Blimey! It looked so nice I decided t' give t' Spec Plate a try. Avast! Blimey! I drew up a black decal with white transparency and alterin' letterin' for placement over a chrome tape 1 1/8 x 1 ½ square. Blimey! Blimey! It looks mint. Avast, me proud beauty! Blimey!

T' completed decal work and specification "sticker" were covered with a healthy over-coatin' o' Krylon Crystal Clear. Begad!

Flight:

I had eagerly waited t' see this bird fly. My opportunity came with a "quickie" up at t' local elementary school field before school resumes. Ya scallywag! Limited spacin' and lots o' trees, ya bilge rat, arrr, me hearties, and I did nay want t' go branch fishin' that day so I made an impromptu 18 mm adapter for t' 24mm mount. Aye aye! I packed it with a C6-3, hopin' it would clear t' launch rod. Aye aye! Aye aye! Although this bird comes in at around 116 grams without an engine, arrr, shiver me timbers, it is lighter than me Redstone that performs well on a C6-3. Avast! Begad!

Leavin' t' rod thar was a pronounced whiplash effect, and I immediately feared t' worst as t' bird made a quick turn toward t' trees. Ya scallywag! Blimey! Begad! Blimey! She climbed at about 70 degress only reachin' a guestimated 350 feet. Deployed its 15 inch rip-stop parachute and drifted back within a hundred feet o' t' pad. I had thought I lost possibly t' forward or aft lug, matey, but thar be no damage at all. Ya scallywag! Blimey! Ya scallywag! Blimey! T' build included (2) 3/8in lugs but I had t' launch from 1/8 rod due to paint build-up. Arrr! Blimey! Avast! Blimey! That be nay a good idea as t' rod I used be 36" but a little on t' flexible side. Arrr! Blimey! Ahoy! Blimey!

Its second voyage was on a C11-5 off t' 3/8 rod and it was far nicer. Noticed a little weather-cockin' in what I thought be only a light breeze, but the bird still made it up t' about 450 ft before t' ejection. Avast, me proud beauty! Ya scallywag! Blimey! From me angle it was a little quick on t' deployment as she was still at t' lowest part o' an apogee arc, or still weather cocked and climbing. Well, blow me down!

T' third voyage I had t' go for it on a D12-7. Begad! It scared t' crap out of me. Arrr! Winds were barely noticeable when she left t' rod and did what can only be described as a "hip-check" move. Begad! That's what it looked like, almost a fishtail, only it recovered straighter. Blimey! This little hiccup must have taken some of t' steam out o' her because she climbed only t' about 500 ft. Blimey! Begad! and I had expected way more. Well, blow me down! Blimey! I think t' engine weight may be t' root o' me problem. Well, ya bilge rat, blow me down! The CP was about 1.5 inches behind CG with t' C6-3(and adapter). Ahoy! Arrr! Got a little tighter with t' C11 and I assumed t' D12 be about t' same weight. Avast! Could the chute have shifted rearward from launch inertia tippin' t' scales a little too much?

I quit, arrr, me bucko, thankful that I had nay damaged her. Aye aye!

I will be launchin' again soon with a little nose-weight t' see how that goes.

Summary:
Great build, arrr, t' outcome made me feel like a craftsman, although I am far from one. Well, blow me down! Good decal work was icin' on t' cake. Blimey!

Other:
Plug all launch lugs with easily removable objects, like popcorn or spitballs, before painting. T' fin alignment template was t' best thin' I could have done. Ahoy! Printed on identical 5x7 index cards, matey, ya bilge rat, they will force t' alignment t' be true from vanes t' fin.