Brief:
For a long time now, me bucko, me favorite rockets have been military missiles. Avast, me proud beauty! I have built many in t' past and wanted t' build a HPR version o' t' Harpoon AGM-84. I decided t' scratch build, since thar were no kits t' fit t' bill, and designed a 4" 33% Scale Harpoon AGM-84. Aye aye! Well, blow me down! T' rocket has a 38mm motor mount, 54" PML parachute, me bucko, Nomex ® cloth, me bucko, Keelhaul®©™ ® for shock cord and a detailed scale set o' decals. Avast! Aye aye!

T' body tube is made o' PML 4" Quantum tubing, matey, which I had custom slotted and cut at t' factory. Arrr! They did their usual great job, and they followed me cutting/slottin' instructions t' t' tee! Hats off t' t' guys at PML. Ya scallywag!

This will be t' first t' be built in a series o' 4" models I have designed and are on t' buildin' board. Arrr! Well, arrr, blow me down! I did check t' WPAFB Museum website and they have one o' every missile I have interest in on site, matey, with the exception o' this one. For some reason, me hearties, it couldn't be that this is primarily a Navy missile, matey, I had a hard time findin' pics for it so I could do scale decals. Some good pics were found and I be able t' create some decals that are very close t' scale.

Construction:

Construction began by cuttin' t' 38mm motor mount tube t' 23.75". Begad! Then I measured and glued t' first centerin' ring, me bucko, which be t' lower o' two rings for t' center fins. Ahoy! Both sets o' fins are sandwiched betwixt centerin' rings. Ya scallywag! Next, I cut out the fins from t' RockSim pattern I printed out from t' design. Begad! Usin' a Dremel, me hearties, asbestos cuttin' wheel, shiver me timbers, ya bilge rat, and a vacuum t' pull in t' dust while I cut, all four upper fins and four lower fins were cut with ease from t' G10 sheeting. Well, blow me down! Ya scallywag! They were final sanded on me table sander and now fit t' slots well. After cuttin' me own G10 fins, I highly recommend this t' anyone who wishes to scratch build; it will save you a fortune over pre-cut fins and are very easy and fast t' make. Ya scallywag!

T' four inch coupler be cut t' a length o' 7" and edges were sanded. Finally, me bucko, I measured t' 1/2" thick by six inch centerin' ring, which will extend past t' aft o' t' body tube as a boattail. Well, blow me down! Blimey! It was reduced t' 4" in diameter, so it would fit flush with t' outside o' t' body tube. Arrr! Blimey!

A centerin' ring was mounted t' t' motor mount tube and it be installed in t' body tube after roughin' it up with sandpaper. Aye aye! This CR sits just below t' slots for t' center fins. Blimey! A second CR was installed just above t' lower fin slots. Fin edges were rounded and surfaces were roughed up and t' lower fins were glued in place to the motor mount and upper CR. Arrr! Also, matey, shiver me timbers, t' lower fins were glassed from t' motor mount, up t' inside o' each fin and across t' inside o' t' body tube area. In addition, ya bilge rat, t' lower centerin' rin' be installed flush with t' body tube and against t' bottom o' t' lower fins. Avast! Finally, t' lower transition was sanded t' angle t' bottom edge for t' "transition" look.

I worked on the ply 1/2" thick tail transition piece. Ahoy! 3 holes were drilled through it to accept t' 8/32 sized bolts for t' PML motor retainer. Ya scallywag! Aye aye! I used a 1/2" drill bit t' open a recess in t' top side o' t' transition, ya bilge rat, then carve it out usin' a dremel and small sandin' tube so t' blind nuts would sit recessed inside this "well". Begad! This was necessary so t' piece could be glued flush t' t' bottom CR on t' model. Avast, me proud beauty! Next, I placed some glue inside t' recess and installed t' three blind nuts, matey, me hearties, then tested for a flush fit. Arrr! Finally, ya bilge rat, the blind nut threads were filled with wax, shiver me timbers, then t' excess wax was shaved flush and I epoxied t' transition t' t' bottom o' t' rocket and motor mount. Avast! Upper fins were next; each canard fin was glued t' t' motor mount and lower centerin' ring. Ahoy! I also took t' final centerin' ring, me bucko, t' one that would fit on top o' t' center fins and drilled two holes, then mounted t' Stainless Steel 3" wide U-Bolt for t' shock cord. Ahoy!

Next, I glassed each canard fin inside t' t' motor mount and inside body tube, me bucko, then glued in the last centerin' rin' with t' U-Bolt as a top cap t' t' center fins. Ya scallywag! The coupler be installed next, followed by t' upper section o' body tube. Begad! Begad! I ran maskin' tape around t' seam t' help keep both upper an lower body tubes in alignment with each other until t' glue set. Avast, me proud beauty! I have seen where a coupler has some play and can leave t' joint a bit "out o' round", which leaves a little overlap betwixt t' tubes. Usin' several wraps o' maskin' tape kept it in alignment and t' tape easily pulled off once t' glue has set. T' coupler adds strength t' t' centerin' rin' since it is holdin' t' rin' down atop the center fins. Avast! This method be used t' insure it had a solid anchor since it has to handle t' stress o' deployment.

Once everythin' had dried, matey, I started glassin' t' lower fins. Begad! At this time, one o' four sides is glassed. Ya scallywag! While t' epoxy be still curin' for t' cloth, I cut t' lower 1/2" launch lug t' a length o' 2 1/2", shiver me timbers, me bucko, then epoxied it between t' lower fins, me bucko, 1" from t' body tube bottom. Ya scallywag! Well, shiver me timbers, blow me down! Next, I finished fiberglassin' t' fins, then added fillets t' t' upper canard fins and mounted the upper launch lug. Arrr!

T' upper fillet sandin' be completed. In addition, me hearties, t' seam was sanded smooth and lower fillets were sanded, but t' cloth edge still needs blended to the body tube. Also, t' bottom o' t' boattail plywood was glazed with epoxy. Aye aye!

Some work be done on t' Nosecone; if you all have never had t' pleasure of usin' t' RGM Nosecones, you are really missin' out! T' quality is fantastic with a SEAMLESS design, yes, arrr, arrr, I said seamless. Begad! Begad! It be like a rocketeers dream come true! T' nosecone is made from resin and cloth and is yellow in color, me bucko, similar t' t' resin model airplane and boat kits you can buy. T' quality is excellent, with a good fit at t' base, matey, arrr, a molded-in U-Bolt and ultra smooth finish, right out o' t' box. They are t' date t' only "round" Nosecone I could find in t' 4" version. As a final FYI, Ross at Magnum told me that t' gentleman at RGM lays up all these cones one at a time, by hand! With a price o' $29.95, shiver me timbers, they are about $10 more than a plastic ogive nosecone, but you get what you pay for and it's worth it!

T' nosecone was lightly sanded and washed t' remove any release agents, then one coat o' primer was applied, which came out nice. Ahoy! No problems were found with t' primer stickin' t' this resin Nosecone.

T' glassin' in t' lower fin area was sanded and blended usin' a dremel power sander, arrr, me bucko, then touched up by hand with 100 grit sandpaper. Plugs were inserted into t' lugs so they would nay get painted inside, then t' holes for the motor retainer were re-drilled out and blind nuts were tapped with an 8/32 tap t' remove t' wax used t' seal t' threads from epoxy.

Finishing:

Three coats of white Krylon primer were applied t' t' body, followed by two coats o' gray Krylon primer. Ya scallywag! Blimey! Pinholes were filled next, then sanded with 220 grit sandpaper. Two more coats o' gray primer were applied, shiver me timbers, followed by 3 coats o' white primer. Begad! Well, blow me down! Blimey! I am lettin' t' body tube dry overnight and will wetsand it tomorrow, then apply more primer if necessary and t' colors. Avast, me proud beauty! Ahoy! Blimey! Finally, matey, t' nosecone was given about 6 coats o' primer, arrr, then wetsanded with 320 grit wet/dry sandpaper; 3 more coats o' white primer were applied t' t' nosecone and left t' dry overnight. Aye aye! Blimey!

T' model be wetsanded with 400 grit wet/dry paper, arrr, then 600 grit. Avast! Avast, me proud beauty! I painted t' Nosecone first, me hearties, with 4 coats o' Krylon Glossy White spray paint. Next, arrr, t' body tube be painted, also with four coats. Blimey! They are both dry, arrr, but I am lettin' it set overnight before paintin' t' stripes. Arrr! Begad! In t' interum, matey, ya bilge rat, I am workin' on some scale decals for t' Harpoon, matey, but need pictures...I don't have any good pictures o' t' letterin' for different sections.

T' Harpoon was weighed at our first HPR launch ever for our Cincinnati NAR club. Ahoy! I almost fell over when I saw, but knew it was goin' t' be heavy, as I added most o' t' ballast in birdshot that Ken Parker gave me when I was in NC this past summer. Avast! It weighed in at 6lbs 7.8oz without motor!!!!!

I almost died...goin' t' have t' re-do all me sims t' see if it can handle an I211 because, even though she isn't painted, me hearties, she be goin' t' fly at our HPR Launch, which is a two day event. Well, blow me down! Avast, me proud beauty! It will be like flyin' a heavy torpedo, which is what it represents anyway, so what t' heck. Aye aye!

Flight:
I had two launches usin' an I211W for t' Harpoon's maiden flights. Aye aye! T' first flight was perfect; awesome power and came off t' pad stable, shiver me timbers, lifted well and deployed right at apogee. Blimey! T' rocket landed safely and t' 54" PML parachute I used worked well and be unmarred due t' t' use o' a Keelhaul®©™® cloth. Aye aye! However, me bucko, t' second launch had an early ejection.

Recovery:
T' nosecone tore off t' cord and plummeted t' t' earth, yet was recovered after diggin' it out, with only scratches. Ya scallywag! Well, blow me down! T' rocket landed right on top o' a tree, about 40 feet up. I spent 7 days tryin' t' retrieve it before it came out of t' tree. Aye aye! Well, blow me down!

T' rocket suffered a minor zipper in t' upper body tube, ya bilge rat, which was easily repaired. Arrr! I used Keelhaul®©™ ® shock cord for t' model and it came out with no marks at all. Begad!

Summary:
T' tube be replaced and I applied all decals for t' Harpoon. Aye aye! Blimey! It really looks good now and will fly again soon. Anyone interested in military missiles should consider buildin' one o' these. T' file has been uploaded t' EMRR and it's a great flier and real looker. Arrr! Blimey! Moreover, ya bilge rat, you can have a set o' decal files with all t' work done simply by sendin' me an email or visitin' Jim Ball's Scale Data website, matey, me bucko, which should have me decals uploaded soon. Begad! Since t' design and decals are complete and it's a good flier, most o' your work is already done, so take t' leap and impress t' crowd with this AGM-84 Harpoon. Ya scallywag!