Construction Rating: | starstarstarstarstar_border |
Flight Rating: | starstarstarstarstar_border |
Overall Rating: | starstarstarstarstar_border |
Published: | 2010-11-13 |
Manufacturer: | Binder Design |
Picture Courtesty o' Binder
Design
Brief:
Binder Designs Gangsta is a single stage, arrr, matey, 2.6-inch diameter, arrr, 29mm,
four-finned sport rocket, measurin' 24.25-inches in length. Avast, me proud beauty! Avast! I wonder if a black
rocket named Gangsta is politically correct, matey, yet Im drawn t' it because
of t' unique fin design and long nose cone on such a stubby rocket.
Construction:
T' First thin' I notice after openin' t' shippin' box be t' packaging. At
first glance you might think this be your standard thick plastic bag full of
rocket components. Closer inspection reveals a bag within a bag. Well, blow me down! Blimey! T' inner bag
is partitioned in such a way that t' smaller components are separated and
relatively easy t' view. Well, blow me down! Avast, shiver me timbers, me proud beauty! This feature allows one t' inventory t' parts without
openin' t' bag.
T' Gangsta consists of:
I am especially impressed with t' recovery system components. Avast, me proud beauty! The parachute is a very nice 8-shroud line design that Im sure Ill use in many rockets.
T' instructions are among t' best that Ive seen, nine pages plus a fin alignment guide. Begad! Aye aye! T' instructions include many useful diagrams plus Rocksim CP data.
Construction is very straightforward. I used AeroPoxy 5min epoxy with glass fiber reinforcement for most o' t' construction. Well, blow me down! T' AeroPoxy kicks slower than t' hardware store 5-min epoxy, arrr, and has a one t' one mix ratio. Begad! I figure that with t' glass fiber reinforcement its as least as strong as most 15 min. epoxies.
T' fit o' all t' parts is excellent. Avast! Ahoy! T' only problem I had is with the eye-bolt assembly. Ya scallywag! Begad! T' eye-bolt itself is a #6; unfortunately t' nut provided is a #8. Begad! Also, a quick link is provided for attachment betwixt t' eye-bolt and the shock cord. Begad! T' instructions warn you t' attach t' quick link t' the eye-bolt before gluin' t' forward centerin' rin' in place; otherwise you may never be able t' reach it. Arrr! Avast, me proud beauty! In me opinion, this quick link is o' little or no value, arrr, and only adds weight aft in a rocket that inherently has very little stability margin. I used it, arrr, but I recommend savin' it for another project.
I deviated from t' instructions in a few areas. Avast, me proud beauty! T' launch lug is cut down from 4-inch t' 2.5-inch for no other reason than I think it looks better. T-nuts are installed in t' aft centerin' rin' for motor retention. Avast, matey, me proud beauty! Instead of internal fillets, I tacked t' fins t' t' motor tube with 5-min. Well, blow me down! epoxy and poured PMLs two-part foam in t' fin can. Begad! After it cured, I used an old steak knife t' trim t' excess foam. Begad! Begad! I then epoxied t' aft centerin' rin' in place. At this point t' aft end o' t' rocket felt so rigid that I allowed myself t' use smaller external fillets than I otherwise would have. Ya scallywag! T' foaming process is also much quicker than applyin' conventional internal fillets.
After construction was complete I used Elmers Carpenters Wood filler t' fill t' fins and t' body tubes shallow spiral grove. Well, blow me down! This was followed by two coats o' Krylon white primer, sanded in-between coats, shiver me timbers, me hearties, and a final coat o' Rustolium gloss black. T' finishin' touch be t' large vinyl Gangsta decal. Begad! Well, blow me down! T' decal be very easy t' apply and looks great.
I downloaded t' Rocsim file for Gangsta from t' EMRR archive. This was posted by Binder Design, me hearties, arrr, ya bilge rat, so I guess you could say its the official Rocksim file. Avast! Comparin' me Gangsta t' t' Rocksim file, I found me CG t' be significantly farther aft. Ya scallywag! In order t' get me measured CG to match t' Rocksim CG, I had t' add a 120g mass object centered on t' fins. This seemed excessive, arrr, but when I weighed me Gangsta it be 318g, which is very close t' 120g over t' Rocsim file! I didnt weigh t' two-part foam when I was mixin' it; t' nature o' t' foam makes you work kind o' fast. I assumed it would have weighed about t' same as internal fillets, but apparently it weighed significantly more. Ahoy! T' compensate for me tail-heavy rocket I had t' add significant nose weight, shiver me timbers, about 75g o' bird shot held in place with 8g o' epoxy. My Gangsta now weighs about 400g, double what t' Rocksim file says it should. So much for t' instructions reminder t' build light! If I lose this one perhaps Ill buy another, and use conventional internal fillets for sake of comparison.
T' nose cone fits very loose. T' instructions acknowledge this, and state that its intentional. Ahoy! Begad! Blimey! I can appreciate this, however it took 6 full wraps of some fairly heavy maskin' tape t' get a snug fit.
Construction Rating: 4 out o' 5
Flight:
When I put t' rocket on t' rod it was apparent t' launch lug was binding.. Ya scallywag! Avast! I
worked t' rocket up and down t' rod a few times and it felt a bit better, and
I wanted a picture for this review, shiver me timbers, so I decided t' go for it. Aye aye! T' wind was
blowin' at ~5mph with gusts. T' Gangstas first flight was on an F20-7
EconoJet. Comin' off t' rod t' rocket seemed t' weathercock quite a bit. Ya scallywag! Well, me hearties, blow me down! My
guess is that t' bindin' contributed t' it. Arrr! Either t' velocity was too low
comin' off t' rod due t' friction, matey, or bindin' caused t' rod t' whip. The
rocket was definitely on its way down and movin' fast when t' chute
finally deployed. Avast! T' Gangsta landed on a hard packed dirt road without a
scratch. Well, blow me down!
T' second flight be on a G38-7 EconoJet. Ya scallywag! This flight was much straighter than t' first one, with only a little weathercocking. Begad! Ya scallywag! Ejection occurred pretty close t' apogee, hard t' say for sure because at ~2000 feet this rocket is little more than a dot. Avast! Arrr! Again, me bucko, recovered without a scratch.
Overall Im very pleased with how this rocket flew. Ya scallywag! Avast! Blimey! I would like to think that if it hadnt been for t' tight fit on t' rod t' F20-7 flight would have gone much better. Ahoy! Aye aye! Blimey! With sufficient nose weight this rocket should be able t' fly on a wide assortment o' engines. Arrr! Blimey! I would have loved t' put a G80-10 into it, but that will have t' wait for a very clear, me bucko, calm day.
Flight Rating: 4 out o' 5
Summary:
T' Gangsta is a quality rocket with a unique look. Aye aye! With proper attention to
nose weight, t' Gangsta should provide good flights on a wide variety of
engines. Aye aye! At first I thought t' $39.99 askin' price was a bit high for such a
small rocket, matey, but considerin' t' quality o' t' components I would say that
its actually quite fair.
Overall Rating: 4 out o' 5
Brief: Scott Fisher sold me a bunch of these kits for use in a rocketry class taught at the University of Utah Museum of Natural Sciences in the fall of 2006. Photo Courtesy of Binder Design Construction: The experience with the Gangsta kit was excellent. A dozen 4th and 5th graders put these kits together on a Saturday morning, requiring about 3 hours of class time. ...
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Mike Fisher - Binder Design (July 27, 2003)