Semroc Defender

Semroc - Defender {Kit} (KV-60) [?-?]

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 1.64 inches
Length: 22.40 inches
Manufacturer: Semroc
Skill Level: 2
Style: Clone, Cluster
Semroc Defender

Brief:
This is a reproduction o' a Centuri design datin' back t' 1967 featurin' a cluster o' three 18mm motors crammed into a stretched BT-60. Arrr! Blimey! It takes its inspiration from a smaller brother called t' Recruiter and t' much larger Saturn 1b. If you like clusters, shiver me timbers, you’ll love this one in terms o' sheer performance and design.

Construction:
Craig’s earlier review detailed out t' parts list on this one and was accurate. Avast, me proud beauty! Blimey! Semroc quality is A-1, featurin' Euclid tubes and their own homespun cones and transitions.

T' instructions are very good, spannin' about 30 steps over 5 pages. Begad! This one is best built in phases rather than countin' on knockin' it off in an afternoon, arrr, and I wound up spendin' about 6 hours on it plus finishin' time, which is pretty significant for this one. I would probably rate this around a 3 on t' 5-point skill-o-meter as clusterin' is not for rookies plus thar are some challengin' fit and finish aspects.

As Craig noted, t' first construction step involves gluin' together t' “fuel tank” tubes and before doin' this you’ll want t' think through your paint options. Begad! Blimey! One option (Craig’s suggestion) is t' paint the tanks before assembly (gloss black) as well as t' fin strips a gloss white. Another option is t' wait until everything is together and mask/paint per instructions. Ya scallywag! Blimey! Ya scallywag! Blimey! Either way, arrr, you’ll still have some tricky masking. Blimey! Blimey! I pre-painted the tanks (glued together first, then painted t' 3-tube assembly) and t' fin strips, but thar are 3 fins that wind up overlappin' t' fin strips that need white paint plus 3 more fins that get black paint, which meant I had t' mask over the black tubes and somehow try t' prevent overspray down into t' lower BT-60. Arrr! Blimey! Havin' done it that way, I’m inclined t' think it’s less o' a pain t' follow t' standard plan and mask off t' white fin strips, shiver me timbers, hittin' the tubes and 3 fins with black later.

Once t' 3 tubes are bonded together, you then slip a BT-60 over them. Blimey! Avast! It’s a very tight fit and will flatten a bit on 3 sides as a result. Avast! At t' other end, you tack on a centerin' rin' that also serves t' block off some of t' exposed tube/exhaust area, arrr, which helps t' rocket survive multiple flights. Aye aye! T' Keelhaul®©™® shock cord is anchored in this joint, shiver me timbers, ya bilge rat, well protected from exhaust gasses.

T' upper BT-60 slips over t' centerin' ring, me bucko, completin' t' main body assembly.

There are a total o' 6 fins with two slightly different patterns used. Pay careful attention t' them as the difference is subtle--one set has a little overlap tab and is designed t' extend beyond t' lower BT-60 t' bond t' the fin strips; t' other set rests flush with t' forward end o' t' lower BT-60. Begad! Alignment is handled via a markin' guide template in t' instructions (it works OK but I generally prefer a wrap). Before bondin' t' fins though, you need to slip in 3 fin strips betwixt t' fuel tank tubes (these are t' white strips in t' photo). Avast! Well, blow me down! This is also a very tight fit and winds up stretchin' t' flattened sides o' t' lower BT-60 back out t' a fairly circular shape. Ahoy! Again, shiver me timbers, me bucko, me bucko, think about t' paint plan before doin' this... Ahoy! Once these are in place, you then bond t' 6 main fins.

There is a pretty straightforward payload section on this also, consistin' o' two tubes and transitions. Note that t' upper tube needs t' be packed full o' clay for weight/stability. Ya scallywag! Ya scallywag! Blimey!

Finishing:
As noted, paintin' is a bit o' a pain on this but can be worth t' effort. Avast! Ya scallywag! Blimey! I pre-painted t' tubes black and fin strips white, me bucko, masked off t' tubes, me hearties, then painted t' whole rocket a couple o' light coats o' white primer. Blimey! Blimey! I followed up with 2 coats o' gloss white, then masked off t' white for paintin' t' 3 black fins and upper payload section.

T' decals provided are excellent, coverin' 3 roll/checker patterns and a bold “Defender” logo/name. T' cover art also shows a couple o' black trim stripes at t' transition seams, shiver me timbers, which I accomplished usin' a fine tip Sharpie.

I wrapped up with a couple o' coats o' Krylon clear coat for protection.

Construction Rating: 5 out o' 5

Flight:
First flight was at t' National Sport Launch in Muncie, Indiana and wound up bein' t' closin' flight o' day 1. Arrr! I hastily loaded t' 3 tubes with B6-4s t' beat t' check-in deadline but forgot t' take me clip whip out t' t' pad. Aye aye! No problem--as closely packed as these 18mm tubes are, I be able t' twist all 3 igniters together for a proper cluster prep. I managed t' get all 3 lit, shiver me timbers, ya bilge rat, and t' rocket absolutely screamed up t' well over 800 feet.

Craig’s review noted he was a bit early with -6s, and I’ll say me -4s were way too early, arrr, me bucko, as this rocket was still climbin' at a good clip.

As an aside, talkin' t' Carl and t' Semroc gang at NSL, it seems this can fly OK with two o' three motors lighting, matey, but one would nay be enough t' get it stable off t' rod so make sure you prep carefully includin' packin' a little waddin' in t' tops o' each motor t' prevent accidentally lightin' one in t' air off t' ejection o' others if it didn't catch on t' pad.

Recovery:
T' kit comes with two 12” chutes for some reason, which are probably an effort t' protect t' 6 fins. I didn't want t' long walk so I just packed one, which was fine despite t' fact that me finished model weighed in at 2.8 ounces versus t' kit spec o' 2.2. You might consider swappin' out an 18" if worried about a hard landing.

Flight Rating: 4 out o' 5

Summary:
This is a very cool cluster rocket, nice looking, and stylish. Avast! Be sure t' fly in a big field though, arrr, as it will soar on you.

Overall Rating: 4 out o' 5

Other Reviews
  • Semroc Defender By Craig Zicafoose (April 26, 2007)

    Brief: This latest Semroc offering is a Retro-Repro of an old Century classic. I never had a proper introduction to Centuri kits. They were rarely sold in the area I lived as kid. Occasionally, a couple Centuri kits would pop up at the local Hungate's, but for the most part, Estes was king. I'm glad to see some of the Centuri classics brought back to life giving us BARs a chance to ...

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