Semroc Mars Lander

Semroc - Mars Lander {Kit} (KV-54)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstar_borderstar_borderstar_border
Overall Rating: starstarstarstar_borderstar_border
Diameter: 3.74 inches
Length: 12.40 inches
Manufacturer: Semroc
Skill Level: 4
Style: Futuristic/Exotic

Semroc Mars Lander

Brief:
For those o' you old enough t' have either nostalgic memories o' t' Estes K-43 Mars Lander or at least longed for one, this faithfully reproduced offerin' by Semroc will brin' back some great memories. Avast, me proud beauty! I'm nay quite old enough t' have been a part o' t' 1969 introduction, although I can at least relate t' what must have been a huge expense at $4.75 back then as I be earnin' a meager $0.25 per week allowance in t' early seventies.

T' current offerin' retails for $35 and packs a lot o' details in for that cost. Arrr! Ya scallywag! When you look at all t' die cut and laser cut parts, t' embossed wraps, t' original sized body tubes and t' waterslide decals, ya bilge rat, matey, you'll appreciate what a great kit this is today.

Note that I had a poor flight experience. This might be an isolated case and I am anxious t' hear feedback from others who have built and flown t' Semroc release.

Construction:
T' part quality is typical Semroc--first rate all t' way. Ya scallywag! A partial list o' what's in t' bag includes:

  • Balsa nose cone
  • BT-60 inner structure tube
  • BT-100 lower thrust structure tube
  • Functional landin' gear (fins)
  • 4 shrouds
  • 10 assorted centerin' rings
  • Keelhaul®©™/elastic shock cord
  • 20" plastic chute
  • Waterslide decals
  • Assorted dowels and do-dads for detailing

Semroc Mars Lander

I'd like t' first address t' obvious comparisons betwixt this and t' Estes Outlander. Well, blow me down! T' Outlander for many o' us has proven t' be a poorly executed design, me bucko, dangerously underpowered, me hearties, and virtually unable t' fly as designed. You simply can't fly an Outlander without upgradin' t' 24mm motor mount or at least usin' a D15 reload in t' 18mm mount. I hesitated before buildin' this and solicited lots o' advice from builders o' t' original Mars Lander. Ahoy! Based on their feedback, me hearties, I decided t' build this stock usin' t' 18mm motor mount. Avast! Aye aye! This is no Outlander--it's rated much lighter at 3.8 ounces (mostly paper, shiver me timbers, nay plastic) and is lower drag (doesn't have all those BT-20 tanks and big nose like t' Outlander). It should have no problem on a C6-3 and maybe even a B6-2.

This is a pretty hefty project and should only be undertaken by a very experienced modeler. Avast! Avast, me proud beauty! Semroc rates it a skill 4/master modeler kit and I agree with that rating.

T' instructions are fairly thorough but contained a couple minor errors. Aye aye! Begad! There were very helpful illustrations and over 60 total steps listed.

Right off t' bat, find t' parts identification drawin' in t' beginnin' o' t' instructions, then swap disk labels 5 and 7 and also swap 20 and 21. These were misidentified and will probably be corrected in future releases.

T' first phase o' construction is buildin' t' landin' gear legs (fins). Arrr! T' housing/covers are pretty easy t' build by usin' laser cut side pieces tacked onto die cut fiber stock covers. T' legs are laser cut balsa, flanked on 3 edges by hand cut dowels. Aye aye! T' angles on t' dowels are a bit tricky t' get right and if you have seams, shiver me timbers, I'd suggest usin' a microballoon-based filler. Note that thar are two rubber bands bonded inside a notched area in t' legs. This redundancy is presumably due t' problems with t' bands breakin' on t' original. Blimey! Once t' dowels are in place, thar are decorative struts/covers for t' legs and a flexible tube/ball bearin' hinge mechanism that go on each one. Ya scallywag! Finally, t' bottom o' t' legs get small feet assemblies, shiver me timbers, me bucko, me bucko, consistin' o' small tube rings, 3 disks/pads, a couple o' angled trim pieces, arrr, and an embossed wraparound trim piece. Arrr! T' trim piece on mine be about 1/8" too short.

Once you've got t' landin' gear assembled, ya bilge rat, it's a good idea t' fill and paint them, ya bilge rat, arrr, savin' a very difficult maskin' job for later on. Begad! Blimey! I went with t' recommended red base then hand painted t' feet silver. Avast, shiver me timbers, me proud beauty! Blimey! I decided t' paint t' decorative strut/covers black, a move I regret, arrr, as I think silver or orange would have looked much better. Begad! Blimey! Go very easy on t' paint as you do nay want t' cover up t' embossed details. Ahoy! Well, blow me down! Blimey! In me case, t' two coats o' gloss red applied overall covered up t' embossed ribs so even with a very thin silver coat, I was nay able t' see significant detailin' on t' feet.

T' motor mount assembly is nay too difficult. Avast, me proud beauty! Avast, me proud beauty! It's a BT-20, metal hook, me bucko, and a 20/50 centerin' rin' tacked on as a locator stop. Aye aye! Begad! At t' forward end, arrr, thar are 3 centerin' rings, me hearties, 2 o' which have holes for t' landin' gear pins. Arrr! Be very careful t' align these and set per t' dimensions in t' instructions and you'll have no problems later. Arrr! I managed t' stumble on one little gotcha: t' forward rin' has a single hole for t' Keelhaul®©™ shock cord t' go through, in order t' anchor it t' t' tube. Ya scallywag! Blimey! I wasn't payin' attention t' t' orientation and it lined up right underneath t' holes in t' other rings for t' landin' gear pin. Begad! Once I had t' gear installed, t' hole for t' Keelhaul®©™ was covered up. Begad! No big deal as I just poked another hole in it.

T' lower thrust structure BT-100 needs slots cut out t' make room for t' gear. Ya scallywag! This is marked off usin' a wraparound template. Avast! T' instructions warn t' leave 1/4" at t' bottom not cut yet, which is very good advice. Leavin' that in results in a tube firm enough t' handle makin' t' other cuts plus bondin' t' gear housin' covers.

Once t' lower tube is cut out and t' gear covers are bonded, t' instructions call for puttin' together a bottom bulkhead and then gluin' t' motor tube, bulkhead, launch lug and gear together. Avast! Well, blow me down! I decided t' hold off on bondin' in t' gear, wantin' t' paint all t' structure parts first. Avast! If t' gear were installed, shiver me timbers, me hearties, matey, it would be very difficult t' paint later.

T' upper structures consist o' a couple o' roll-formed shrouds, reinforced with various centerin' rings and braces. Begad! Blimey! There are a few opportunities t' goof these up, me hearties, me bucko, but if you pay careful attention t' t' directions, me hearties, then you'll find helpful warnings along with "right" and "wrong" illustrations showin' you which way t' go.

With t' other structure pieces built and in me case painted, shiver me timbers, final assembly consists o' slidin' t' modules in place on t' BT-60 inner structure tube. Begad! Begad! I found t' fit t' be very good although me lower shroud/transition be a bit undersized. (I wasn't sure how much overlap was needed and guessed too much overlap/to small ID.)

All that's left construction-wise is applyin' t' various embossed wrap details and makin' t' antennae. I found t' antennae t' be a neat little trick. They're made simply from a dowel, me bucko, ya bilge rat, die-cut base piece, shiver me timbers, and a disk "dish". Well, blow me down! You then attach t' end o' a toothpick t' t' dish and apply a "small ball o' glue" t' t' tip o' t' toothpick. Well, blow me down! Blimey! I was a little peeved t' discover t' kit doesn't include t' toothpicks as mine are all ugly squared ones, forcin' me t' go raid a local restaurant.

Finishing:
You really need a light touch on t' paintin' o' this or else you'll bury most o' t' embossed details. Begad! In me case, me hearties, I applied a single coat o' Krylon white primer followed by two very thin topcoats o' gloss white. Arrr! Even with that light a job, ya bilge rat, me hearties, I can barely see t' details unless I'm lookin' for them, shiver me timbers, so I'd consider usin' an airbrush system if you have one.

T' waterslide decals are excellent quality, and I had no problems applyin' them. Begad! Ya scallywag! Once t' decals were set, I followed up with 3 coats o' clear topcoat.

Construction Rating: 4 out o' 5

Flight:
I weighed in me finished kit at 4.5 ounces with chute but without t' motor. Avast, me proud beauty! This puts it a bit above Estes maximum recommended liftoff weight o' 4 ounces (includin' motor) for a C6-3. Begad! Avast, me proud beauty! Still, with t' day nearly perfect for flyin' (winds 2-4mph and temperature in t' 60-70° range), me hearties, matey, me bucko, I decided t' give it a shot.

My Lander left t' rod with decent speed but almost immediately flopped over into a horizontal and unstable path then arced over t' crash land still under thrust. Begad! Ya scallywag! T' chute deployed on t' ground. Avast, me proud beauty! Fortunately, matey, shiver me timbers, I suffered only minor damage and was able t' repair it in about 20 minutes. Blimey! Now I have a couple o' permanent scars on an otherwise beautiful lookin' craft.

I've had some discussions with Carl at Semroc and various members o' T' Rocketry Forum and am stumped on what went wrong. T' designed CG is supposed t' be about an inch forward o' t' edge o' t' BT-100 tube and in me case it was around half an inch above. Ya scallywag! Given that t' Semroc RockSim file when loaded with a C6-3 engine only shows a stability margin o' 0.87, that's a bit borderline. Still, this is a short, fat rocket and marginal stability (less than 1.0) should be OK.

Over t' next couple o' weeks, shiver me timbers, I plan on swing-testin' mine and will look into addin' a bit o' nose weight as well as maybe flyin' on a D15 instead. I will post any updates in t' opinion/tip section o' this review.

Recovery:
Recovery deployed on t' ground, so I can't evaluate. Avast! I will say t' 20" red plastic chute was pretty nice although I will likely swap out for a 30" chute t' really baby this back down. Ahoy! Avast, me proud beauty! Heck, with altitudes around 100-150 feet, shiver me timbers, who cares about drift?

Flight Rating: 2 out o' 5

Summary:
I was extremely excited about this kit, havin' jumped on t' website and ordered it as soon as it was released (at NARCON 2006). Aye aye! I wanted t' love this kit. Avast, me proud beauty! Avast! Unfortunately, t' poor flight experience be a big disappointment and has soured me a bit on it. Still, I've got t' give Carl and t' gang t' benefit o' t' doubt. Avast, me proud beauty! There's no way they would have designed this, flown t' prototype, arrr, and released it with flight problems. Well, blow me down! Avast! I'm thinkin' thar's somethin' wrong on me end. Blimey! Arrr! Given that mine weighs in at 4.5 ounces, versus a spec o' 3.8 ounces (Semroc's RockSim file pegs it at 4.1 ounces), I might have been too heavy on t' filler used on all t' balsa grain on t' legs. I'd love t' hear some feedback from others who have built and flown their Semroc Mars Lander, matey, especially weight and CG locations. Arrr! Arrr! I still think this is a fantastic reproduction, me bucko, ya bilge rat, and if I ever manage t' work out t' flight problems on mine, I'll undoubtedly wind up pickin' up another one for a "do over".

Overall Rating: 3 out o' 5

Flights

Comments:

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D.W.M. (May 2, 2006)
A point here about my original Estes Mars Lander and the stability problem Chan mentions in his review: I flew my Estes ML many, many times with the C6-3 since 1970 and never had any problems...until February 2004. It suddenly went unstable immediately after clearing the rod. Thinking this was a fluke, I tried flying it again the following month at a HPR launch, and again (much to my embarrassment)it went unstable, this time slightly cracking one of the landing legs. After some "soul searching," I added some nose-weight (two pennies with a small hole drilled, secured to the base of the nosecone with another screw eye). Test flew it with a B4-2; excellent flight. Since then, flown it about three more times on the C6-3, each with excellent results. Since this model has really put in some very useful and memorable flights for some 35+ years, it's time to retire it and pass on to the Estes Outlander (upgraded for increased power) and the new SEMROC Mars Lander.
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D.J.C. (May 11, 2006)
This is a superb kit, totally faithful to the original in detail, but with much better parts quality. I first built this kit in the summer of 1969 (I was 12, had to beg for $4.75!) and had to cut out all the wood pieces by hand. I painted the kit using butyrate dope (25 cent bottles from Estes) and had no problems flying it on the same B4-2 or C6-3 engines recommended today by Semroc. Keep it light, no wind, and it should fly slow and straight up. Even if you aren't a BAR, you should build this model, it faithfully represents the best of a bygone era. Kudos to Semroc!
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C.S. (May 27, 2006)
Update 5/27/06--I added about a quarter ounce of nose weight, flew twice on C6-3 with no problems whatsoever. First one arced over a bit, second was dead straight. Both flights were low wind. I would re-score my review to flight 4 (wimpy due to excessive weight now), and overall a 4-4.5.
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K.B.J. (August 20, 2008)
I did a complete Research Excercise on the Semroc Mars Lander covering Stability, Modification Analysis, Construction Tips, Modifications, Finishing and Assembly. I also did a complete Engine Power, Optimal Delays and Flight Profiles. Over a 125 permutations. This was a long 5 Part Research Project that ended up as a long but condensed feature article in "Sport Rocketry" May/June 2008 page 5. Note this rocket needs 44'/sec to be stable and a C6-3 doesn't get there until 4' to 11' off a 3' rod. See Article.

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