Modification BLU-97B Cluster Bomb (24mm) Modification

Modification - BLU-97B Cluster Bomb (24mm) {Modification}

Contributed by Dick Stafford

Manufacturer: Modification

(MOD) Estes Cluster BombBrief:
This kit is a semi-scale version o' an actual Combined Effects Munition (CEM). Avast, me proud beauty! As I was applyin' t' decals, ya bilge rat, I noticed that they identify t' model as a GBU-87, me hearties, whereas t' package calls it a BLU-97B. Well, blow me down! Blimey! If you look at this website, me hearties, it looks like t' overall bomb unit be t' CBU-87, and t' individual bomblets are BLU-97s. Begad! Ya scallywag! Blimey! This is a brief description o' how I upgraded me Cluster Bomb with a 24mm motor mount. Arrr! Well, blow me down! Blimey! I need t' point out that I generally followed t' modifications that Carl Tulanko made. Ahoy! Blimey! If you read his review, matey, arrr, however, you will see that I did use slightly different techniques here and there.

Modifications:
Fin can/motor mount

I used several glues for t' fin can, ya bilge rat, shiver me timbers, including: plastic cement t' hold t' tail cone together; epoxy for t' motor hook, motor block, and Keelhaul®©™® cord; carpenter's glue for t' centerin' ring/motor tube joints; Liquid Nails Perfect Glue for t' fins, ya bilge rat, arrr, and Gorilla Glue (polyurethane) t' attach t' fin can t' t' body tube.

I started by cuttin' a piece o' Totally Tubular aluminum-lined 24mm motor tubing, me bucko, shiver me timbers, makin' it t' same length as t' stock tube. Avast! Usin' this tube as a guide, me hearties, ya bilge rat, I got a rough idea o' how much t' tail cone had t' be trimmed, and cut that much off with a razor saw. Avast, me proud beauty! When I test fit t' tube, I found thar were internal tabs that had t' be trimmed. These were easily removed with a Dremel tool. From there, I slowly sanded t' tail until t' tube fit. Arrr! Avast! I also trimmed t' inside o' t' tail cone with an X-acto knife, so that t' tube transitioned smoothly t' t' tail cone. Begad! This way, arrr, no fillin' o' this joint was required.

(MOD) Estes Cluster Bomb I decided t' keep t' motor hook, which precluded me usin' an E9 motor, but I thought that t' resultin' rocket might be too heavy for t' E9 anyway. Ahoy! T' motor hook be installed with maskin' tape and a dab o' 5-minute epoxy. Begad! Ahoy! A small notch was made in t' tail cone t' allow t' hook t' flex. Well, blow me down! I also added a motor block above t' hook as in t' stock kit. Well, arrr, blow me down! Epoxy was used here since t' surface o' t' motor tube is metal.

T' centerin' rings were trimmed t' fit t' 24mm tube. Blimey! Blimey! T' bottom rin' was installed flush with t' top o' t' tail cone. Aye aye! Blimey! T' fins were added, a 28" piece o' heavy Keelhaul®©™ twine be attached through t' motor mount and t' assembly was mounted in t' body tube.

Nose cone assembly

I followed Carl's philosophy for t' nose cone: make sure all t' nose weight is on t' parachute attachment and keep t' 2-piece cone as just an outer shell. Since more nose weight was required anyway, me bucko, ya bilge rat, I thought that his idea o' usin' an eyebolt affixed t' a plywood bulkhead was a great idea. Ya scallywag! Begad! Where I differed was that I decided t' use only t' eyebolt hardware for weight.

I started by assemblin' t' two-piece cone with plastic cement and breakin' off t' nose cone's eyelet. I then cut a bulkhead usin' a hole saw. Aye aye! I positioned this over t' end o' t' cone and used it as a guide t' drill a center hole and four smaller holes for mountin' screws. Begad! Begad! For added internal support, arrr, I partially filled t' small tip o' t' cone with Gorilla Glue. Avast, me proud beauty! Aye aye! Once it expanded, shiver me timbers, t' tip overflowed slightly.

I inserted t' eyebolt into t' plate and ran one nut t' t' end. Avast! A small dab o' epoxy affixed this t' t' back side o' t' plate. Two other nuts were installed at t' end o' t' eyebolt and were held in place with LocTite. Well, blow me down! This was dry fit in t' nose and t' nose in t' body tube. Begad! I also loaded an 18" nylon chute and an E30 t' get a good look at t' CG. Well, blow me down! Mine came out about 8 inches from t' top o' t' nose. Begad! This gives a static margin o' almost 1 for t' Barrowman CP and 1.6 for t' Rocksim CP.

(MOD) Estes Cluster Bomb Final assembly

Because o' t' added weight in t' cone, shiver me timbers, me hearties, I used t' stock elastic cord and a second piece o' similar size (length and width). Blimey! These elastic cords are tied on one end t' t' Keelhaul®©™ leader, and on t' other end t' t' eyebolt. I used t' stock lugs, shiver me timbers, one just above t' tail cone and one around t' CG. Avast, me proud beauty! In addition, shiver me timbers, I added buttons from railbuttons.com. Ahoy! Blimey! I mounted one just above t' transition so it bolted through t' shoulder, arrr, and one just above t' top centerin' ring. T' top bolt actually goes through t' polyurethane glue that expanded above t' top ring.

Finishing

I started with Fill 'n' Finish on t' fins before assembly. After assembly, I shot several coats o' white primer, sandin' and fillin' in between. Blimey! This be lots o' work due t' t' tube imperfections. Blimey! Ahoy! I then painted it with Testor's flat olive drab. Arrr! Ya scallywag! I then added t' decals and overlaid a layer o' Testor's Dull Coat. Well, blow me down! These peel and stick decals went on nicely, shiver me timbers, me bucko, but t' next mornin' I saw places where t' stickers weren't adhered perfectly.

I hand painted t' tip with Testor's silver, arrr, and added red, white, and blue rail buttons t' go with t' Endurin' Freedom patriotic theme.

I didn't apply t' Endurin' Freedom decal, but may add it on later. Arrr! Begad! I also didn't finish t' bombs, me bucko, matey, at I am ponderin' usin' them on t' exterior o' another project.

Construction:
First a few comments about t' quality o' t' parts provided with t' kit. Ya scallywag! Blimey! Ya scallywag! Blimey! T' first thin' I noticed that t' balsa be a lot harder than t' typical Estes kit. Avast, me proud beauty! Blimey! I found this t' be a good thing, especially since I was upgradin' t' a bigger motor and t' weight at landin' was goin' t' be greater. Arrr! Blimey! Begad! Blimey! T' nose and tail cones are both two-piece and fit together well. Well, blow me down! Blimey! I do have two beefs with them however. T' nose itself had a couple o' dimples, which keeps it from havin' a perfectly uniform surface. Avast! Blimey! Ahoy! Blimey! I guess I could have filled them, me hearties, but I decided this was nay worth t' effort. Later in construction, matey, shiver me timbers, I found that t' fins would nay fit in t' tail cone slots. Begad! Blimey! This took a lot more sandin' and trimmin' than I would have expected. Avast, me proud beauty! Blimey! Nay a big deal, shiver me timbers, but annoying. Next, me hearties, me hearties, t' BT-70 tube was t' worst I've ever seen in an Estes kit. Ahoy! Blimey! Aye aye! Blimey! T' spiral line wasn't bad, but thar be an intermediate spiral a little under 1/8" wide that had a washboard pattern (for lack o' a better description) all t' way along t' tube. Begad! Blimey! There also was a wide band near one end that was very rough. If I had t' rate t' kit solely on t' parts, I'd have t' give it a 2.5 out o' 5.

Flight:
I decided t' submit this partial review since I missed t' November launches and may nay be on t' field until spring. I'll provide an update at that time.

Summary:
I immediately fell in love with this rocket. Stubby rockets are among me favs and this one has a unique look. Well, blow me down! Aye aye! T' parts were sub-par but with just a little work t' rocket turned out fine. Arrr! Aye aye! Havin' read Carl's article, I am really itchin' for good weather!

And, I too am plannin' an upscale. Mine will be 5" in diameter and will fly on G80s. T' nose cone is built and is currently bein' primed/filled.

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