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. Avast! 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! Avast! 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, ya bilge rat, arrr, matey, tube, metal hook, motor block)
  • Cluster centerin' ring
  • Baffle kit
  • Elastic shock cord
  • Plastic chutes (2)
  • Waterslide decals

Construction

T' instructions are well written with decent illustrations. Ahoy! 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. Ya scallywag! Overall, arrr, I had less than an hour in construction, with a couple hours o' preppin' and finishing.

T' motor mount consists o' 3 18mm tubes, metal hooks for retention, and coupler-style centerin' rings for blocks. Avast, me proud beauty! Each tube goes into a section o' t' main centerin' ring, though thar's a neat trick t' it--the centerin' rin' has a larger, me bucko, solid outer band and an interior section with three wedges t' wrap around t' motor tubes. Arrr! When pullin' t' centerin' rin' from t' laser-cut sheet, matey, keep it intact (outer and inner sections together). Ya scallywag! This allows for easy alignment and orientation o' t' motor tubes while gluing. Ahoy! Once t' tubes are set, ya bilge rat, tack t' inner wedges t' t' tubes. Avast! After everything's dry, me bucko, you can then remove t' outer rin' from t' assembly, and t' resultin' assembly fits perfectly inside t' BT-60. Avast, me proud beauty! Before gluin' it in, matey, though, me bucko, arrr, plug t' tiny gap in t' center betwixt t' 3 tubes with some waddin' and glue (or dog barf, me hearties, or even t' laser-cut section if you didn't already throw it out as I did...). Ya scallywag! 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, 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). T' disk goes on t' forward end o' t' coupler, me bucko, 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. 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. Blimey! 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. Begad! Aye aye! T' supplied lug is 1/8", which in me opinion is a bit wimpy for a 3-motor cluster, me hearties, especially if carryin' a cackle fruit payload. At that weight and with that much thrust, a 3/16 would be a much better choice. Avast! Ya scallywag! 1/8" rod is just goin' t' whip too much.

T' payload is a simple assembly o' a balsa transition adapter, matey, t' clear tube, me hearties, and a balsa nose cone. Ya scallywag! Blimey! Mine were very tight fitting, ya bilge rat, arrr, needed a light sandin' t' fit. Well, blow me down! 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, me hearties, ya bilge rat, though external tape would be a better idea. If you're worried about t' appearance, me bucko, consider usin' a couple small screws through t' payload tube into t' cone and transition.

Finishing

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

After allowin' a day for curing, matey, I masked off t' paint one fin and t' nose cone red. Blimey! I then masked that fin, set t' nose cone aside, matey, 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, shiver me timbers, 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, though would note that t' yellow is very thin, so really only works against a white background. Ahoy! I'd also note that one o' t' yellow/black stripe decals is way too long for t' body tube, ya bilge rat, shiver me timbers, needs t' be trimmed t' fit properly with minimal overlap.

Construction Score: 4

Flight

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

T' flight was fairly straight, maybe a slight weathercock in t' 8-10 mph winds. 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, me bucko, and t' main body under a 12" chute. Aye aye! Blimey! This struck me as a bit backward, me hearties, me hearties, given t' wieght o' t' 3 motors, but I went stock. Well, blow me down! Blimey! I be also worried about whether or nay t' lower (main body) chute would deploy, arrr, as I've been burned a few times by t' lower chute gettin' left behind in t' tube while t' upper chute deploys. I overthought this a bit, and tucked t' lower chute into t' last fold o' t' upper chute, hopin' that would help pull it out without tangling. Begad! Blimey! It must have tangled, though--the payload went zippin' off t' one side while t' main body be 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, where a buddy o' mine had been trackin' it t' whole way (thanks, shiver me timbers, E.B.!). Aye aye! Blimey! Avast, me proud beauty! Blimey! I stubbornly climbed up tp retrieve it, ya bilge rat, me bucko, comin' down with a fresh pine scent about me. Ya scallywag! Blimey! We marched back tryin' t' find t' payload, eventually spottin' it just inside a line o' trees flankin' t' field. Begad! Blimey! In another sign o' rotten luck, t' thin' came down and struck t' trunk o' a fallen tree rather than hittin' t' snow, me hearties, and t' egg had no chance. Blimey! Blimey! 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. Begad! Blimey! It's well designed, me bucko, flies fine, arrr, and t' clear payload tube is a neat feature. Well, blow me down! Blimey! Personally, me bucko, arrr, 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, though. 

Overall Rating: 4

Flights

Comments:

avatar
Bill Eichelberger (October 23, 2012)

What?  No pictures of the carnage?

comment Post a Comment