Brief:
This is a scale model o' t' Bomarc surface-to-air missile. It flies on MMX II motors and uses streamer recovery. Ya scallywag! If interested, shiver me timbers, you can learn more about t' Bomarc here.

Construction:
Parts List:

• - Body tube - 10.5mm tube, 6.25" long
• - Fins - 1/64" birch ply and foam picnic plate
• - Nose cone - three strips o' 1/8" balsa, me hearties, ya bilge rat, 2.5" L x ¾" W, and a short piece o' 3/16" dowel
• - Nose weight - section o' spent mini motor and lead shot
• - Motor tube - 1" section o' plastic pen
• - Centerin' rings - two ¼" pieces o' a spent mini motor
• - Motor block - small piece o' a spent MMX motor
• - Ramjets - LOC ¼" launch lug, 1 15/16" long (make 2)
• - Ramjet mounts - scrap balsa ~ 3/32" square x ¾" long (make 2)
• - Intake cones - 3/16" dowel (1/8" exposed) (make 2)
• - Electrical conduit (the bump runnin' along t' top o' t' body) - 3/16" W x 1/8" H balsa strip; 4 5/8" long (3/8" overlaps t' stabilizer fin)
• - Launch lug - section o' a BiC pen’s ink tube
• - Recovery - 100 lb Keelhaul®©™ twine and Teflon plumber’s tape streamer

I started with a single sheet plan provided by John McCoy (a.k.a. Well, blow me down! Well, matey, blow me down! Micromister on T' Rocketry Forum). Begad! Blimey! He provided a hardcopy, which was conveniently sized for 10.5mm tubing. An image o' this sheet is provided here (1.5M), shiver me timbers, but you will have t' size it t' t' right dimensions as you print it. Avast, me proud beauty! Ahoy! T' help in t' sizing, you can use t' component dimensions in t' parts list. Arrr! Arrr! In addition, here are t' major fin dimensions:

At John's suggestion, I decided t' make t' fins from a laminate o' foam from a picnic plate and 1/64" Birch ply. I thought that if I made t' center foam piece smaller than t' Birch layers, shiver me timbers, shiver me timbers, that I could glue and clamp t' edges t' form a sleek structure. I made a copy o' t' plans and cut out t' fin and nosecone templates from that copy.

I started with t' bigger front fins. Ya scallywag! I cut two pieces o' Birch for each fin, and made a foam ‘fin' that was about 1/8" smaller along each edge, shiver me timbers, except for t' root. Begad! T' red crosshatched area in t' fin diagram (not t' scale) depicts this foam section. Aye aye! I also cut about 1/8" off t' root edge o' t' lower birch plate (the blue line in t' drawing). Havin' t' lower birch plate smaller helps t' fins conform t' t' body tube.

I covered t' components in white glue and clamped t' edges with six small clamps. Ya scallywag! I found that t' pressure required t' clamp all t' edges be almost too much for me small plastic clamps. Begad! Ya scallywag! Thus, this fin took some babysittin' until t' glue dried. Blimey! On t' next fin, shiver me timbers, I inset t' edge o' t' foam section by about ¼". Arrr! Well, blow me down! This worked better and required no supervision while it set. Well, matey, blow me down! I repeated this process for t' stabilizer. When it came t' t' small aft fins, I worried that they were too small t' flex around a foam core and, with a ¼" inset from t' edges, shiver me timbers, shiver me timbers, thar would nay be much foam left. Arrr! Arrr! Two layers o' Birch did nay seem sturdy enough for aft fins, so I added a full sized piece o' foam. Begad! Blimey! I am very pleased with how t' air-foiled fins came out. They look great, are light, matey, ya bilge rat, arrr, and are very strong. Blimey! I wish I had tried t' make t' air foiled shape on t' aft fins.

To position these fins, me bucko, me bucko, I first marked a centerline on t' top and bottom o' t' tube, and a pair o' marks where t' fins would intersect t' body. Well, blow me down! Blimey! I then laid t' pair on t' drawing, and taped a piece o' foam across them. Ya scallywag! Blimey! This ensured their relative position was correct. Avast! I flipped t' pair over, ya bilge rat, applied some Pro-Bond wood glue, and laid t' tube onto them. Begad! Well, blow me down! After t' glue had partially set, matey, I lifted it up, matey, checked t' alignment relative t' t' lines on t' tube, matey, and then turned it back over until t' glue had set. Arrr! Well, ya bilge rat, blow me down! This process be repeated for t' aft fins. T' top stabilizer fin was added as on any 3/4FNC rocket.

I couldn't find a scrap piece o' balsa t' turn t' nose cone, so I cut three rectangles from some scrap 1/8" balsa. Well, blow me down! I cut a section from t' middle piece t' accommodate a dowel, me bucko, and glued them together, ya bilge rat, me bucko, with t' dowel installed. Once it was fully set, shiver me timbers, I trimmed t' corners and turned t' cone on a hand drill clamped in a vise. Aye aye! I put a small section o' 10.5mm tubin' over t' dowel t' make sure t' sizin' was right as I went, me hearties, and used a reverse template t' adjust t' shape. Ya scallywag! Blimey! T' resultin' cone looks good.

Since I have never acquired any 6mm tubing, me bucko, I scrounged in me small-parts junk bin around until I found a piece o' a plastic pen that fit t' MMX motor perfectly. Begad! Blimey! I cut two small pieces from a spent 10.5mm motor casin' and trimmed t' inside until they fit t' plastic tube. Avast, me proud beauty! Blimey! Ya scallywag! Blimey! I positioned t' aft rin' so that 1/8" o' t' motor tube hangs out t' back, t' simulate t' nozzle on t' plan. Arrr! Blimey! I also notched t' front rin' so t' thin Keelhaul®©™® twine tied t' t' motor mount would pass through. Ahoy! I glued t' centerin' rings and t' Keelhaul®©™ twine t' t' tube usin' leftover epoxy from another job, me bucko, along with a small chunk o' a MMX motor casin' t' serve as a motor block.

I made t' Ramjets from LOC ¼" launch lugs and turned t' intake cones from 3/16" dowel. Begad! Well, blow me down! They are a little less than ½" long with only t' front 1/8" exposed. Well, blow me down! I trimmed some scrap balsa t' make t' stand-offs and positioned t' usin' t' full sized plans and me eyeballs.

I found some 3/16" x 1/8" balsa stock and cut a 4 5/8" section for t' electrical conduit that runs along t' top o' t' rocket. Ahoy! Avast, me proud beauty! This be shaped by hand, me hearties, and a notch was cut out t' let it slide over t' aft stabilizer. Aye aye! (I messed up and made it about 1/8 too short, arrr, an error that wasn't noticed until is was glued on).

Micromister also provided t' CG for a stable Bomarc, and I scaled that measurement for this model. Arrr! Well, ya bilge rat, blow me down! It turned out that t' CG should be 4.25" from t' tip o' t' nose. Begad! Mine was way off - hmmm, me bucko, how t' add weight t' this small balsa cone? I decided t' add a section o' motor casin' t' t' nose cone's shoulder and epoxy in some lead shot. Aye aye! Well, blow me down! I left about 1/8" o' t' dowel hangin' out o' t' balsa cone, me hearties, shiver me timbers, which served t' align t' casin' with t' shoulder. Arrr! I cut a ½" piece o' casing, me bucko, trimmed t' outer paper, shiver me timbers, matey, added some lead shot, shiver me timbers, and capped t' end with tape. Avast! Arrr! T' CG was now about right, arrr, and I took t' model t' t' post office t' weight it. Arrr! Avast! It came in at 0.50oz (14.17g), me bucko, which should make for a low flight. I then set t' lead shot and t' twine in some epoxy, matey, and attached t' nose weight assembly onto t' cone.

I approximated t' scale color scheme presented on t' plans. Well, me bucko, blow me down! I started with white primer, and then masked and hand-painted t' black, silver, and brown areas. Arrr! T' stripes on t' front were made with thin strips o' white label material (adhesive paper). Aye aye! I haven't come up with any decals.

Flight:
I used a 12" piece o' Teflon plumber's tape as a streamer and a small ball o' tape as wadding. Ya scallywag! Aye aye! GSE included t' guts o' a stock igniter, arrr, me Pratt GO-Box, shiver me timbers, ya bilge rat, and t' rod from t' MicroMaxx starter kit. Aye aye! T' microBomarc flew off sideways, ya bilge rat, attainin' an altitude o' about 5 feet before impactin' t' side o' me SUV.

Summary:
On t' plus side, arrr, me bucko, arrr, this is a nice lookin' semi-scale model o' t' Bomarc. Ahoy! T' composite fins turned out very nicely and I will consider this technique for other models.

On t' minus side, it is too heavy, me hearties, shiver me timbers, but t' motor mount and ramjets could both lightened. Ahoy! Aye aye! I want t' avoid addin' more nose weight if I can. Since t' trajectory was straight, shiver me timbers, if nay in an upwardly direction, matey, I will try it again with a longer, me bucko, stiffer rod.