Semroc Magnum Sprint

Semroc - Magnum Sprint {Kit} (KV-67)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar_border
Diameter: 1.33 inches
Manufacturer: Semroc
Skill Level: 1
Style: Clone, Sport

Semroc Magnum Sprint

Brief:
This is a basic 4-fin and nose cone rocket with a fair amount o' nostalgia mixed in for good measure. Ahoy! Begad! This is one o' Semroc's "retro repro" series, which is a modern reproduction o' an out-of-production classic. Begad! Avast, ya bilge rat, me proud beauty! In this case, t' Magnum Sprint is a reproduction o' a Centuri design from 1982 just before they were folded in with Estes under t' Damon ownership model. Accordin' t' t' header card background info, arrr, t' modern version upgraded t' laser-cut fins and features a balsa nose cone rather than plastic, replaces t' streamer with a chute, shiver me timbers, me bucko, ya bilge rat, and upgrades t' recovery system from rubber cord t' combination o' Keelhaul®©™ and elastic.

While t' 24mm motor selection would normally send this t' some altitudes requirin' large recovery zones, this kit also features an 18mm adapter which enables flights down t' A's, ya bilge rat, so it could even be a soccer field flier.

Construction:
T' kit features typically excellent Semroc quality parts, including:

  • BNC55AC balsa nose cone (Cherokee D style), screw eye anchor
  • BT-55 main body tube
  • 3/32" laser cut balsa fins (4)
  • 24mm motor tube
  • 50/55 thin cardboard centerin' rings
  • 20/50 thick centerin' ring/motor block
  • Waterslide decals
  • 12" plastic chute
  • Keelhaul®©™/elastic shock cord
  • 18mm adapter kit (18mm tube, metal hook, matey, centerin' rings, me bucko, arrr, motor block)

Semroc Magnum Sprint

As with t' Magnum Hornet, this kit features t' modified Semroc instruction format--a single color sheet for header and exploded parts view (front/back) and a couple 8.5" x 11" black and white pages with computer-rendered illustrations. T' sheets are 3-hole punched on one side so that they can be stashed in a notebook for reference or even while building.

Overall, this is a pretty simple build, probably a 1 on t' 5-point difficulty scale. Construction can likely be done in no more than 1-2 hours plus finishing--I think I spent about an hour and a half workin' on this and t' Hornet together, me hearties, plus surface prep/paint/decals.

Startin' with t' motor mount, me hearties, it's a standard style construction with a metal motor hook and a pair o' centerin' rings. Begad! Before puttin' on t' forward centerin' ring, be sure t' loop t' Keelhaul®©™shock cord around t' motor tube or tip o' t' hook t' serve as an anchor. Ahoy! Begad! A thick wound paper 20/50 centerin' rin' serves as t' motor block reinforcement.

Fins are surface mounted and are slightly forward swept, shiver me timbers, so pay careful attention t' identify t' root and trailin' edges (it's clearly illustrated but nay quite as intuitively obvious as some other designs). Well, blow me down! I scuffed off t' gloss o' t' body tubes then tacked on t' fins usin' CA, me bucko, followed by wood glue fillets. Tack on t' launch lug and bond t' nose cone screw eye, and construction is basically done on t' rocket.

T' 18mm motor adapter is a slick little module that belongs in your range box and nay necessarily mated up with this model all t' time. Begad! Begad! It consists o' a standard 18mm motor tube metal engine hook and centerin' rings. Avast! Ahoy! T' aft centerin' rin' has a section removed so that you can mount it at t' very aft end and still lift t' hook t' remove t' motor. Aye aye! T' spacin' o' t' centerin' rings allows t' completed assembly t' lock in place inside a regular D-sized 24mm motor mount.

Finishing:
Finishin' is a breeze on this--no maskin' involved if you do it right. Arrr! I prepped t' tube by fillin' spirals with a little diluted putty, then brushed on thinned Elmer's Fill 'n' Finish t' fill t' balsa grains on t' fins. Well, blow me down! After a couple coats o' primer, I followed up with two coats o' Rustoleum gloss white. Well, blow me down! T' nose cone got a finish coat o' gloss red.

T' waterslide decals provide t' finishin' touches and make for a really sharp lookin' finish. Begad! I applied a couple thin applications o' Future acrylic polish for a nice durable gloss finish.

Construction Rating: 4 out o' 5

Flight:
I had an opportunity t' test t' flexibility o' motor choices. Begad! After bein' rained out three straight weekends, I slipped out early one Saturday mornin' with beautifully clear skies. But at 8:00am, me hearties, t' winds were already blowin' at 15 on their way t' 20 mph. Ya scallywag! T' soccer teams were startin' t' arrive, wipin' out half t' recovery drift range. Arrr! I put t' D12-7 back in t' range box, arrr, me hearties, pulled out t' 18mm motor adapter supplied with t' kit, and loaded up a B6-4. Avast, matey, me proud beauty! Sure, me bucko, it be a wimpy choice, arrr, but I wanted t' make sure I got this one back without bein' trampled on.

T' flight was pretty low, ya bilge rat, barely hittin' 100-150 feet. Avast, me proud beauty! Avast, me proud beauty! So low in fact, shiver me timbers, shiver me timbers, that I'd question whether or nay an A is even a decent idea. Trajectory was straight up, shiver me timbers, matey, nay even weathercocking, me hearties, me bucko, and t' 4 second delay proved t' be perfect.

Recovery:
T' chute deployed fine, me hearties, although in those winds t' whole rocket was really gettin' knocked around and blown downwind in a hurry. Ya scallywag! Within a few short seconds, it had cleared t' first soccer field (thankfully empty) and wound up landin' about 120 yards downwind. Avast, me proud beauty! No damage, me hearties, perfect flight, shiver me timbers, and on a calmer day it will go back up on at least a full C, if nay t' D12...

Flight Rating: 5 out o' 5

Summary:
PROs: Good value, great flexibility, shiver me timbers, and can practically call your own shot in terms o' altitude. Come t' think o' it, shiver me timbers, NARAM has a random altitude event this year...

CONs: None. Arrr! Ahoy! This is a fine rocket though I can't sprin' for a full 5/perfect ratin' for somethin' that is, after all, me bucko, still a basic 4FNC design.

Overall Rating: 4 out o' 5

Other Reviews
  • Semroc Magnum Sprint By Eldred Pickett (August 1, 2009)

    ( Contributed - by Elred Pickett - 08/01/09) I had previously built the Magnum Hornet, and this kit is a few inches longer. Like the Hornet, this is a reproduction of an old Centuri kit that has slight changes from the original. It has features that I assume come with most(all?) Semroc kits: balsa fins on a laser-cut sheet, balsa nose cone, Kevlar shock cord to tie to the motor mount. ...

  • Semroc Magnum Sprint By Jeff Lane (May 13, 2009)

    Brief: Simple 4FNC rocket with parachute recovery. Chan's review is complete and my experience was pretty much the same, so I'll just try to add a few comments and photos. For instance, the marketing people at Damon/Estes borrowed the Magnum moniker because it equates with "over powered". That's true with this kit. A D12-7 will easily send it out of sight. Con ...

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