Semroc Scrambler

Semroc - Scrambler {Kit} (KV-34)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Published: 2011-02-09
Diameter: 1.80 inches
Manufacturer: Semroc
Skill Level: 2
Style: Clone, Cluster, Payload, Sport

Brief

This is a Semroc retro-repro o' t' Estes Scrambler originally designed by Bill Simon in 1968. Well, blow me down! Blimey! It's basically a stretched version o' t' 3x18 clustered Astron Ranger with a clear payload tube to accommodate an egg. Well, blow me down! Ya scallywag! Blimey! T' Semroc kit offers a few convenient upgrades--an ejection baffle and laser-cut fins.

Components

Parts were excellent quality and include:

  • Balsa nose cone
  • Balsa transition/adapter
  • BT-60 body tube
  • Laser-cut balsa fins (3)
  • 18mm motor tube assy (3x, tube, me hearties, metal hook, matey, motor block)
  • Cluster centerin' ring
  • Baffle kit
  • Elastic shock cord
  • Plastic chutes (2)
  • Waterslide decals

Construction

T' instructions are well written with decent illustrations. Aye aye! Begad! Though buildin' a cluster can be tricky, Semroc has made this about as simple as possible, and t' skill ratin' o' 2 is a fair assessment. Well, blow me down! Overall, I had less than an hour in construction, with a couple hours o' preppin' and finishing.

T' motor mount consists o' 3 18mm tubes, matey, metal hooks for retention, and coupler-style centerin' rings for blocks. Well, shiver me timbers, blow me down! Each tube goes into a section o' t' main centerin' ring, me hearties, shiver me timbers, though thar's a neat trick t' it--the centerin' rin' has a larger, solid outer band and an interior section with three wedges t' wrap around t' motor tubes. Avast, me proud beauty! Blimey! When pullin' t' centerin' rin' from t' laser-cut sheet, keep it intact (outer and inner sections together). Ahoy! Ahoy! This allows for easy alignment and orientation o' t' motor tubes while gluing. Well, blow me down! Once t' tubes are set, tack t' inner wedges t' t' tubes. Begad! Ahoy! After everything's dry, arrr, you can then remove t' outer rin' from t' assembly, and t' resultin' assembly fits perfectly inside t' BT-60. Before gluin' it in, though, plug t' tiny gap in t' center betwixt t' 3 tubes with some waddin' and glue (or dog barf, arrr, or even t' laser-cut section if you didn't already throw it out as I did...). Blimey! Aye aye! Semroc even made sure thar were slight notches for t' hooks, which helps make sure t' tubes are oriented in such a way that all three hooks pull away without interference, me bucko, makin' motor loading/unloadin' quick and easy.

T' BT-60 gets marked for fins and launch lug via a template on t' instruction sheet.

T' baffle is a relatively light duty design, consistin' o' a coupler section about 2" long and a single baffle disk (fiberboard with some holes). Ya scallywag! T' disk goes on t' forward end o' t' coupler, me bucko, arrr, so a good glue joint is essential (or a good fillet when placin' in t' tube) t' prevent it from blowin' out t' front o' t' rocket. Blimey! T' baffle also serves as t' shock cord anchor point--slip t' elastic through a slot on t' disk and glue/knot t' t' other side. T' completed baffle assembly is then glued into t' body tube about 4-5" back from t' forward end.

Fins are precut, just needed a light sandin' before tackin' on with CA then applyin' wood glue fillets.

Launch lug needs a small wood standoff due tot eh larger diameter payload tube. Ahoy! Avast, me proud beauty! T' supplied lug is 1/8", which in me opinion is a bit wimpy for a 3-motor cluster, especially if carryin' a cackle fruit payload. At that weight and with that much thrust, arrr, a 3/16 would be a much better choice. 1/8" rod is just goin' t' whip too much.

T' payload is a simple assembly o' a balsa transition adapter, t' clear tube, me hearties, and a balsa nose cone. Aye aye! Mine were very tight fitting, matey, needed a light sandin' t' fit. Blimey! If you're goin' t' fly this with payloads, you'll need t' consider how t' keep everythin' together here. A friction fit could work, arrr, though external tape would be a better idea. If you're worried about t' appearance, consider usin' a couple small screws through t' payload tube into t' cone and transition.

Finishing

For t' paint scheme on this, I set t' clear payload tube aside and taped t' nose cone shoulder t' t' transition forward shoulder, then shot everythin' with a couple coats o' primer. Arrr! I'd pre-treated balsa with Fill N Finish and filled spirals with a smearin' o' wood putty. Begad! After sandin' away most o' t' primer, I then followed up with two coats o' gloss white.

After allowin' a day for curing, I masked off t' paint one fin and t' nose cone red. Ya scallywag! I then masked that fin, set t' nose cone aside, shiver me timbers, and masked off t' transition (upper half) and painted t' 2 remainin' fins and upper transition gloss black.

I wound up hand paintin' t' cone and transition shoulders gloss black, me hearties, though a strip o' black tape would do just as well behind t' clear tube.

This has a number o' somewhat zany decals offerin' plenty o' opportunity t' give t' model a somewhat customized decoratin' scheme. Arrr! I found t' decals easy t' work with and apply, me bucko, ya bilge rat, though would note that t' yellow is very thin, me hearties, so really only works against a white background. Blimey! Aye aye! I'd also note that one o' t' yellow/black stripe decals is way too long for t' body tube, needs t' be trimmed t' fit properly with minimal overlap.

Construction Score: 4

Flight

This is a 3-motor cluster, me bucko, shiver me timbers, so prep is nay exactly simple. Begad! Begad! Thanks t' t' alignment o' t' motor hooks, matey, arrr, securin' t' motors be easy. Ya scallywag! I'd normally use Quest Q2G2 igniters for clusters, me hearties, ya bilge rat, arrr, which fire instantly and have longer leads, but stupidly left them behind. Aye aye! Instead, arrr, arrr, I went with standard Estes igniters, twisted in parallel hookup. Avast, me proud beauty! Ahoy! Usin' a Pratt launcher powered by me car's battery, shiver me timbers, ignition be quick and I successfully fired all 3 C6-5's. Arrr! Avast! T' Scrambler, me bucko, complete with a fresh egg in t' payload, was on its way.

T' flight was fairly straight, me bucko, me hearties, maybe a slight weathercock in t' 8-10 mph winds. Avast, me proud beauty! T' -5 delay was perfect, just after it had arced over.

Recovery

Recovery is intended t' be two-part, with t' payload bay comin' down under a 16" chute, and t' main body under a 12" chute. Begad! Blimey! This struck me as a bit backward, me hearties, me bucko, given t' wieght o' t' 3 motors, but I went stock. Ahoy! Blimey! I was also worried about whether or nay t' lower (main body) chute would deploy, as I've been burned a few times by t' lower chute gettin' left behind in t' tube while t' upper chute deploys. Well, blow me down! Blimey! Ahoy! Blimey! I overthought this a bit, arrr, and tucked t' lower chute into t' last fold o' t' upper chute, hopin' that would help pull it out without tangling. It must have tangled, me hearties, though--the payload went zippin' off t' one side while t' main body was comin' down under a single bright red chute--the chute intended t' support t' payload. 

My main body drifted and drifted, landin' about 25 feet up in a pine tree, shiver me timbers, where a buddy o' mine had been trackin' it t' whole way (thanks, me hearties, E.B.!). Avast! I stubbornly climbed up tp retrieve it, me bucko, comin' down with a fresh pine scent about me. Ya scallywag! We marched back tryin' t' find t' payload, shiver me timbers, eventually spottin' it just inside a line o' trees flankin' t' field. Avast, me proud beauty! In another sign o' rotten luck, me hearties, shiver me timbers, t' thin' came down and struck t' trunk o' a fallen tree rather than hittin' t' snow, and t' egg had no chance. Avast, me proud beauty! Begad! T' Scrambler lived up t' its name on this flight...

Flight Rating: 4

Summary

For folks nostalgically fond o' t' original Scrambler or even t' Astron Ranger, this kit certainly has a lot o' appeal. It's well designed, flies fine, and t' clear payload tube is a neat feature. Arrr! Arrr! Blimey! Personally, ya bilge rat, I'd prefer t' fly me cackle fruit on less risky single motors, but I do enjoy t' occasionaly wow factor o' seein' t' multiple plumes and smoke o' a good cluster. Ya scallywag! Blimey! I'd think about bringint it down tethered together, arrr, though. 

Overall Rating: 4

Flights

Comments:

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Bill Eichelberger (October 23, 2012)

What?  No pictures of the carnage?

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