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

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

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

Construction:

Construction began by cuttin' t' 38mm motor mount tube t' 23.75". Ahoy! Then I measured and glued t' first centerin' ring, matey, shiver me timbers, which be t' lower o' two rings for t' center fins. Both sets o' fins are sandwiched betwixt centerin' rings. Well, blow me down! Next, I cut out the fins from t' RockSim pattern I printed out from t' design. Usin' a Dremel, matey, asbestos cuttin' wheel, 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. Arrr! 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. Ahoy!

T' four inch coupler was cut t' a length o' 7" and edges were sanded. Finally, shiver me timbers, 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. Avast, me proud beauty! Blimey! Arrr! Blimey! It was reduced t' 4" in diameter, so it would fit flush with t' outside o' t' body tube.

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

Next, me bucko, I glassed each canard fin inside t' t' motor mount and inside body tube, then glued in the last centerin' rin' with t' U-Bolt as a top cap t' t' center fins. Well, blow me down! The coupler was installed next, ya bilge rat, matey, arrr, followed by t' upper section o' body tube. Ya scallywag! 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! Ahoy! I have seen where a coupler has some play and can leave t' joint a bit "out o' round", arrr, which leaves a little overlap betwixt t' tubes. Blimey! Usin' several wraps o' maskin' tape kept it in alignment and t' tape easily pulled off once t' glue has set. Aye aye! T' coupler adds strength t' t' centerin' rin' since it is holdin' t' rin' down atop the center fins. Begad! This method was used t' insure it had a solid anchor since it has to handle t' stress o' deployment. Begad!

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

T' upper fillet sandin' was completed. Blimey! In addition, ya bilge rat, t' seam be 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. Blimey! Begad!

Some work be done on t' Nosecone; if you all have never had t' pleasure of usin' t' RGM Nosecones, shiver me timbers, you are really missin' out! T' quality is fantastic with a SEAMLESS design, yes, 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, similar t' t' resin model airplane and boat kits you can buy. T' quality is excellent, ya bilge rat, with a good fit at t' base, me hearties, a molded-in U-Bolt and ultra smooth finish, right out o' t' box. Well, blow me down! They are t' date t' only "round" Nosecone I could find in t' 4" version. Arrr! As a final FYI, Ross at Magnum told me that t' gentleman at RGM lays up all these cones one at a time, ya bilge rat, matey, by hand! With a price o' $29.95, matey, me bucko, 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, me bucko, which came out nice. Ya scallywag! Avast, me proud beauty! Blimey! No problems were found with t' primer stickin' t' this resin Nosecone. Avast, me proud beauty! Avast! Blimey!

T' glassin' in t' lower fin area was sanded and blended usin' a dremel power sander, me hearties, arrr, 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. Avast! Ya scallywag! Blimey!

Finishing:

Three coats of white Krylon primer were applied t' t' body, arrr, followed by two coats o' gray Krylon primer. Begad! Aye aye! 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. Aye aye! Avast, me proud beauty! 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! Ya scallywag! Finally, t' nosecone was given about 6 coats o' primer, then wetsanded with 320 grit wet/dry sandpaper; 3 more coats o' white primer were applied t' t' nosecone and left t' dry overnight. Begad!

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

T' Harpoon was weighed at our first HPR launch ever for our Cincinnati NAR club. Aye aye! I almost fell over when I saw, but knew it was goin' t' be heavy, ya bilge rat, as I added most o' t' ballast in birdshot that Ken Parker gave me when I was in NC this past summer. Arrr! 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, matey, she be goin' t' fly at our HPR Launch, me hearties, which is a two day event. Avast! It will be like flyin' a heavy torpedo, which is what it represents anyway, so what t' heck. Ya scallywag! Avast! Blimey!

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

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

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

Summary:
T' tube was replaced and I applied all decals for t' Harpoon. Aye aye! 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. Ahoy! 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, arrr, which should have me decals uploaded soon. Avast, me proud beauty! Ahoy! 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. Avast, me proud beauty!