Stellar Dimension Vector Review

Stellar Dimension Vector

Contributed by Mark Fisher

Construction Rating:
Flight Rating:
Overall Rating:

Rocket Pic T' Stellar Dimensions kits looked so interestin' that I had t' try one. SDI has a lot of other kits like t' Vector, and all are pretty reasonably priced; I paid $8 for mine from Discount Rocketry.

***Essence Ratings***
Construction	3
Flight	2
Overall	2½

Assembly

T' kit itself is very different than others I'd built, consistin' almost entirely o' laser cut wood pieces, me hearties, and a lot o' them, matey, arrr, 46 in fact. T' only things that aren't are t' nylon engine retainin' ring, t' launch lugs made from small brass rivets, me bucko, and t' recovery system. Avast! T' later is a 12" plastic parachute and a freakish 12" length o' rubber about 0.070" in diameter for a shock cord. Arrr! While this rocket has a very ingenious ejection baffle system (waddin' is still required), ya bilge rat, me bucko, shiver me timbers, I was worried that rubber wouldn't hold up long, so I replaced it with a 12" length of Rogue's light duty KC-4 Keelhaul®©™® and an 18" length o' ¹/8" shock cord. Ya scallywag! I also used an Estes 12" 'chute instead, as I already had one built. Plus, the SDI 'chute looks like a pain t' build, arrr, and its shroud line mounts don't look very durable.

T' instructions are poor, with only three illustrations. Also included in t' kit is a brief science fiction story (that isn't very well written) on a separate sheet which would be better used for expanded kit instructions. Begad! If you've ever built a laser cut kit o' any type before, me bucko, me hearties, you won't have any trouble, though, t' pieces fit together rather intuitively, you'll only need t' consult t' directions in a few places.

***Specifications***
Overall Length	17⁵/8" 448 mm
Effective Diameter	1¹/16" 27 mm
Fin Span	4" 102 mm
Dry Weight	1²/3 oz. 47 g.

Many o' t' pieces would've broken if I'd've removed them from their stock without cuttin' them free. Begad! T' material reminds me o' t' cheap wood I used to get in "wood burning" kits as a kid, somehow artificial but with a distinct grain and fairly friable. Ahoy! Most o' t' pieces needed only a light sandin' t' remove t' tiny tabs left, though some had relatively large tabs and required some special attention. Also, me kit was missin' two o' t' required slots in t' lower body panels t' mount t' launch lug assemblies, ya bilge rat, so I used a short piece o' Estes lug instead. Arrr! Other than that, me hearties, t' kit went together very fast, arrr, nay one piece failed t' fit, ya bilge rat, and even bendin' t' wood pieces that formed the nose cone wasn't difficult. Ya scallywag! Blimey! Usin' CA really sped things up, t' entire bird was together in under an hour, me bucko, and ready for flight in less than two.

Finish

While most others stain (and even polyurethane) their SDI rockets t' brin' out t' finely laser-etched details, arrr, me hearties, I choose t' paint mine with a translucent enamel I'd been wantin' t' try. Arrr! Blimey! It worked out all right, most o' t' etched details are still quite visible t' the naked eye (the camera has trouble pickin' them up), me hearties, me bucko, though I'd like t' add a gloss clear coat t' help smooth t' surface a bit. Avast! A combo poly-stain would make a great choice, too, though a thorough sandin' would be required between coats.

T' mediocre laser cuttin' and poor instructions and materials offset the phenomenal fit, finely etched details and ease o' assembly enough that I'd rate this bird a 3 on t' Essence scale for construction, ya bilge rat, just average.

Flight

Estimated
Performance
Engine	AGL (ft.)	Speed (ft./s)	Accel (Gs)
A8-3	160	105	15.1
B4-4	365	170	16.1
B6-4	380	195	16.3
C6-5	720	295	19.1

The instructions don't include a recommended motor list, though t' bag art does claim that t' Vector can be flown on A, B and C engines. I used wRASP to develop a list o' those Estes and Quest motors that have appropriate delays. T' Vector would also fly reasonably well on Estes' A10-3 mini engine and Apogee's A2-5, B2-3, B7-4 and C4-5, arrr, though you'd have t' build custom adapters for them. Ya scallywag! Estes and Quest 18 mm motors fit t' square engine mount like a glove, me hearties, with positive contact on all four sides. Ya scallywag! T' CG is about 4¹/8" from t' aft end with an Estes B6-4 loaded.

Flight tests were conducted at Live Oaks Vocational School on Sept. Blimey! Avast, me proud beauty! 10th, 1999 @ 10 AM, matey, me hearties, before solar heatin' kicked up any serious winds, though thar be a 2-3 MPH intermittent breeze from all directions. Begad! Sky was clear and temperature was about 75ºF. Blimey! My Vector's first flight on an A8-3 be better than I thought it would be, but it did wobble a little and burned t' 'chute a bit at ejection. Avast! Ahoy! She recovered OK, though, with no damage. Her next flight on a B6-4 had a lot more wobble, and she weathercocked into t' wind some. Ahoy! I used more waddin' this time (six squares instead o' three), arrr, and t' 'chute was none t' worse for wear, but the waddin' didn't come all t' way out at ejection.

These flights caused no damage t' t' rocket itself, though t' baffle plates were covered with soot and burned ejection particles. Ahoy! With no real good way t' clean these, they'll eventually clog up enough t' restrict t' ejection charge, but I don't know if that's good or bad. After these two flights, me bucko, the engine compartment and top o' each engine also had some soot, indicatin' a poor seal betwixt t' engine and aft baffle plate. While a standard, shiver me timbers, cylindrical wound kraft-paper body tube would probably violate some paradigm held by the manufacturer, it would solve all these problems.

Both ejections appeared t' be very close t' apogee, ya bilge rat, confirmin' me estimated CD o' 1.1. On t' second ejection, t' nylon engine retainin' rin' came off and was lost forever in t' grass o' t' launch field. Avast! Avast! When I got home, ya bilge rat, I cut off the rin' mountin' tabs and added an Estes engine hook, me hearties, which you can see in the photo at right. Blimey! I cleaned up t' soot in t' engine compartment with a damp towel and retouched t' paint before I took t' photos.

Though t' Vector presents no more frontal area than a typical Estes E2X bird like t' Banshee or Hijax, shiver me timbers, and weighs about t' same, her rough, blunt leadin' edges and poor surface finish detract from her performance. The Vector's less than "stellar" flights, wobble, poor ejection gas management, ya bilge rat, me hearties, and t' loss o' t' engine retainin' rin' make me rate her a 2 on the Essence scale, needs improvement.

Summary

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