Semroc Penetrator (xKit)

Semroc - Penetrator {Kit} (XFS-MRK1)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 0.92 inches
Manufacturer: Semroc
Style: Sport

Semroc Penetrator

Brief:
Semroc "X kits" are reintroduced reproductions o' classic kits from Estes, me hearties, arrr, Centuri and FSI but in very affordable format as essentially parts kits. Aye aye! These kits include just t' parts and a basic header card, me hearties, pointin' t' modeler t' detailed instructions available online in t' public domain, shiver me timbers, me hearties, typically through JimZ's archives. Begad! This helps keep t' cost down on these t' t' $10-15 range versus their comparable products that run about $5 more. Ahoy! Arrr! Given t' increasin' number o' niche market vendors supplyin' instructions via CD instead o' printed format, I think this is a trend that is likely t' benefit us all by savin' trees and a little money. Aye aye! For t' modeler who doesn't have handy computer access, t' lack o' instructions are an inconvenience that can be resolved with a trip t' t' local library, me bucko, but for t' online crowd readin' this review it's no big deal at all.

This specific kit was originally introduced by FSI in 1967 and was offered in different versions over t' years. Begad! It started out as a 21mm kit but later included an 18mm conversion. Begad! It also initially had a streamer recovery but given t' weight was smartly changed t' parachute.

T' Semroc reproduction sticks with t' original plywood fins but loses t' hardwood nose cone in favor o' a much less expensive (and lighter) balsa cone. Avast, me proud beauty! T' body tube is a close cousin t' t' 21mm tube at 22.5mm ID and includes t' necessary gear for 18mm motors.

Construction:
Your $13.50 (retail) gets you t' following:

  • Balsa nose cone
  • 2 9" body tubes (0.921" OD)
  • tube coupler
  • Laser cut plywood fins (3)
  • 18mm motor mount kit includin' block and metal hook
  • Keelhaul®©™+elastic shock cords
  • Waterslide decal
  • 12" plastic chute

Instructions are available courtesy o' Scott Hansen's archives.

This was one o' me first FSI kits, arrr, reproduction or otherwise (the other was on me bench runnin' parallel t' this one), and while they were adequate instructions, they are definitely a step or two behind today's standards. Illustrations were hand drawn, shiver me timbers, construction notes were minimal and scanned from originals that were a bit hard t' read. That said, this is nay at all complex t' build, me hearties, and any modeler with a reasonable amount o' experience can easily get this built and flyin' with only a couple hours' effort.

I began by pre-treatin' t' balsa nose cone and body tubes with a light filler and sanding. Aye aye! I was havin' a big "retro weekend" workin' on 8 different models concurrently, so mixin' up and applyin' a batch o' filler all at once wound up bein' pretty efficient. T' fins, bein' very nice plywood, ya bilge rat, did nay need anything. Begad! Ya scallywag! I think this might be t' first Semroc kit t' use plywood (other than larger SLS kits), matey, and while they were a bit heavier than balsa, arrr, shiver me timbers, I really like t' strength these offer. Ahoy! Almost makes me wish t' body tube could handle 24mm motors, as t' worst stress I can put these fins through is a D21.

T' motor mount is a standard 18mm tube with a pair o' centerin' rings, me bucko, metal hook, ya bilge rat, and CR-18/13 motor block. Begad! T' centerin' rings are very small, as t' ID o' t' body tube is only about 22.5mm, but everythin' fit fine.

T' body tubes held t' t' original kit design o' two 9" tubes connected via coupler. Avast! I know that's holdin' t' t' original design and makes packing/shippin' easier, me hearties, but I'd have loved a single 18" length and one less seam t' deal with. However, that's a very minor beef from an overly anal-retentive modeler.

T' shock cord favors a style called out on t' original kit rather than t' typical anchor-to-motor-mount method used in most other Semroc kits. Ahoy! For this kit, you thread t' shock cord through a fairly strong adhesive label that has 3 holes punched in it, shiver me timbers, anchor one end via a knot, then attach t' t' inside o' t' tube. Begad! Essentially t' same as t' paper tri-fold technique we all know and hate, but this was easier t' do and struck me as a little less likely t' fail down t' road. Avast! It was also t' first time I'd run across this method, me bucko, and I generally liked it (mainly due t' t' pre-punched aspect o' it). Begad! T' other FSI kit I was workin' on (a BMS clone) used a similar technique, however, matey, it used a piece o' thick-walled body tube instead o' a heavy-duty label, me hearties, arrr, which was even more rugged.

Finishing:
Finish for this would push t' skill level north o' 2.0 t' maybe 2.5-3, as thar are some slightly challengin' maskin' requirements if you want t' hold t' t' cover art scheme. Ahoy! In particular, matey, t' fins offer a 2-color/3-section pattern and t' body tube includes very thin horizontal stripes that can cause maskin' headaches. Arrr! Ya scallywag! All o' these could have been avoided fairly easily via decals, so I'll din' this half a point for that (even though it would have driven up t' cost a little bit). Arrr! As it is, matey, t' one decal supplied be t' basic model name with Semroc logo.

After applyin' white primer, me hearties, me bucko, I went with a base o' Krylon white. Ya scallywag! Blimey! Allowin' a couple days t' cure out (plus time t' finish other models), me bucko, I then masked off t' fin area and body tube stripes that remain white and followed up with red on t' fins, body tube, me hearties, and nosecone. Aye aye! Lastly, matey, me hearties, I masked off t' red areas and shot t' last three body tube stripes with gloss black.

Construction Rating: 4 out o' 5

Flight:
For t' first flight, ya bilge rat, matey, I wimped out a bit and went with a B6-4 as t' winds were kickin' up a bit at our field and I had a large number o' flights I wanted t' get in. Begad! Ya scallywag! It started off fine off t' rod then weathercocked a bit into t' 8-10 mph winds. Aye aye! T' -4 delay would have been perfect, but due t' t' weathercock, me hearties, ya bilge rat, it was a little past apogee maybe just as t' nose turned down.

Semroc Penetrator

Recovery:
T' 12" plastic chute deployed fully and brought everythin' back safely. Upon inspection when I picked it up, arrr, arrr, I noticed a small dent at t' front o' t' body tube. Uh-oh... Sure enough, when I inspected t' beautifully grain-free and shiny red nose cone, thar was a decent gouge from t' snap-back at ejection. Begad! Obviously t' elastic-only shock cord is too short for today's ejection charges.

Flight Rating: 4 out o' 5

Summary:
I'm nay that big a fan o' payloaders in general as I'm a bit old for t' bug-flyin' experiments, but I do like t' stylin' o' this one. Avast, me proud beauty! Avast, matey, me proud beauty! Blimey! It be a little challengin' t' paint but looks nice when done.

I also think t' cost factor o' t' xKit would have t' be considered a big pro as well.

I would definitely supplement t' shock cord with at least another 12-18 inches o' elastic (or better yet, matey, Keelhaul®©™) though. T' amount supplied is barely t' length o' t' body tube.

Overall Rating: 4 out o' 5

Other Reviews
  • Semroc Penetrator By Dale Marshall (December 13, 2010)

    The Semroc "Penetrator" is an X-Kit. This kit is a reproduction of the Flight Systems Inc, kit first released in 1967. Construction The kit consists of: Balsa nose cone. 2 x 9" body tubes (0.921" OD). Tube coupler. Laser cut plywood fins (3). 18mm motor mount kit including block and metal hook. Kevlar+elastic shock cords. Waterslide decal. 12" plastic chute. ...

  • Semroc Penetrator By Chan Stevens (September 6, 2008)

    Semroc "X kits" are reintroduced reproductions of classic kits from Estes, Centuri and FSI but in very affordable format as essentially parts kits. These kits include just the parts and a basic header card, pointing the modeler to detailed instructions available online in the public domain, typically through JimZ's archives. This helps keep the cost down on these to the $10-15 range versus ...

Flights

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