Centuri Black Widow

Centuri - Black Widow {Kit} (5036, KB-6) [1963-1981]

Contributed by Drew Tomko

Construction Rating: starstarstarstar_borderstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Centuri
Style: Multi-Stage
Centuri Black Window by Semroc

Brief:
A clone o' t' classic Centuri two-stage Black Widow usin' Semroc parts. Well, blow me down! The "unique glidin' booster" feature is a great crowd pleaser. Blimey! Semroc has all t' parts includin' t' outside passport stage coupler with pre-drilled holes, matey, decal, and a beautiful set o' laser-cut fins that includes t' balsa fin fillets for t' booster.

Construction:
Parts list with Semroc part numbers:

  • 1 BC-733 Balsa Nose Cone #7 3.3"
  • 1 CP-12BY Chute Pak - 12"
  • 1 EC-118 Elastic Cord 18"
  • 1 FV-5 Black Widow Laser-Cut Fins
  • 2 HTC-7 Tubin' Coupler #7 1.0" Long
  • 1 HTC-7B Tubin' Coupler #7 Outside 1.0" Long
  • 1 Engine hook
  • 1 SCK-24 Keelhaul®©™® Thread 100# 24"
  • 1 ST-740 Body Tube #7 4.0"
  • 1 ST-790 Body Tube #7 9.0"
  • 1 TB-7 Thrust Block #7
  • 1 Black Widow decal

I also used a fiber engine hook lock rin' that goes outside t' #7 booster BT. This is mylar in t' original kit.

Centuri Black Window by Semroc I followed t' instruction found on Jim Z's site. It is a straightforward build. In Step 2, shiver me timbers, ya bilge rat, I cut one o' t' 1" couplers t' 1/2" t' duplicate the original's 1 1/2" coupler. Blimey! One major correction: in step 3, arrr, matey, do nay use the 1 1/4" measurement for t' engine hook lock ring. Ya scallywag! Instead, shiver me timbers, shiver me timbers, lay one o' the laser-cut booster fins against t' BT with t' aft edge flush with t' aft of the BT and mark where t' fin cut out is on t' BT. Ahoy! Begad! I used t' measurement and the fins didn't line up so they were too far forward. I wound up loppin' off 1/2" o' t' booster on me next try, arrr, figurin' t' length o' t' BT was wrong (don't ask, it's a long story) and this cost me some scorchin' on my first flight. Blimey! T' 4" length is correct--it's t' lock rin' measurement that is wrong on t' instructions.

T' rest o' t' assembly went easily. T' instructions have handy fin guides. Begad! Make sure you use t' correct one for each stage. Avast! T' booster fins are offset slightly t' allow t' glidin' recovery. Begad! Sandin' t' balsa booster fin fillets takes a bit o' time, but they really add t' t' strength o' the booster. Aye aye! I also used t' more modern method o' attachin' a line o' Keelhaul®©™® thread t' t' upper stage engine block and attachin' t' shock cord t' that. You'll need t' stack t' 1" and 1/2" couplers inside t' booster BT. Semroc has t' passport stagin' outside coupler pre-drilled with two vent holes. Arrr! Ahoy! Make sure one o' t' holes is nay directly beneath a fin on t' upper stage or you will get scorching. Begad! It's tricky t' line t' holes up with two holes and three fins. Begad! I would also recommend soakin' t' inside o' all the stage couplers with CA for durability. T' top o' t' booster BT needed a good amount o' sandin' down t' get a nay too tight fit inside t' stage coupler.

Centuri Black Window by Semroc

Finishing:
I really wanted t' duplicate t' catalog picture and it was a challenge. Begad! Blimey! After applyin' a couple coats o' Elmer's Fill 'n' Finish t' t' spirals and fins, I gave it two coats o' primer, ya bilge rat, maskin' off t' top o' t' booster BT where it goes inside t' stage coupler. Avast! I gave t' nose cone two coats o' gloss white and t' rest o' t' rocket two coats o' gloss black. Avast, me proud beauty! Begad! Now t' fun began. I decided t' use white self adhesive Trim Monokote t' do t' white areas on the BT and fins. Begad! Arrr! First I used paper t' plot out t' curvin' patterns through trial and error. Begad! Ahoy! Then I transferred those templates t' t' Trim Monokote and cut them out with a sharp hobby knife. Avast, me proud beauty! Arrr! Trim Monokote is peel and stick and permanent once you put it on. I applied water with a few drops o' dish detergent t' the areas first and this gives you time t' adjust before t' adhesive grabs. It was tricky around t' balsa booster fin fillets and I needed t' touch those up with white paint, but t' final effect is very striking. Begad! I finished with a thin band of chrome Trim Monokote at t' top o' t' second stage BT, and t' Semroc decal on one o' t' fins.

Construction Rating: 3 out o' 5

Centuri Black Window by Semroc

Flight:
T' engine hook in t' booster and passport stagin' make this easy t' prep for flight. Ya scallywag! For t' first flight I didn't have any A8-5s and just used an A8-3 I had in t' box. Avast! T' booster had a B6-0. Begad! Blimey! I wrapped a bit o' maskin' tape around the upper stage motor. Aye aye! Begad! Although it flew very nicely, arrr, matey, arrr, ejection be obviously too early. Begad! I was lucky t' avoid a zipper. T' first flight be with t' incorrectly shortened booster, and t' inside o' t' coupler on t' upper stage was seriously scorched and cracked. Begad! I am pretty sure this was because thar wasn't enough o' t' booster's BT in thar protectin' t' coupler from t' booster engine's charge. After this I added a 1/2" piece o' BT with an inside coupler t' t' booster. I also sanded down t' coupler and recoated it with CA. I made 3 flights with a B6-0 t' A8-5 combination and they were beauties. On the first two flights, t' booster fluttered down, however, shiver me timbers, after addin' more clay to t' front end o' it, it glides reasonably well if a bit steeply.

Recovery:
Again, ya bilge rat, me bucko, I would recommend a Keelhaul®©™® shock cord attachment. Ahoy! Blimey! Blimey! Blimey! T' trickiest part o' recovery is gettin' t' booster to glide. Avast, shiver me timbers, me proud beauty! Blimey! Hand tossin' wasn't really a good indicator o' glide. After a couple of flights, arrr, I got t' clay weight right. Begad! Blimey! It's a pretty amusin' sight watchin' the booster straighten out and glide down. Also make sure you coat t' inside of the stage coupler with CA as t' design with t' coupler attached t' t' upper stage instead o' t' lower is prone t' scorching. Also usin' t' correct measurements helps!

Flight Rating: 4 out o' 5

Summary:
This is a classic beauty and a pretty easy build, me bucko, although it takes a bit of fiddlin' t' get right. It's a strikin' lookin' rocket and produces interesting flights with t' glidin' booster. Avast, me proud beauty! Aye aye! T' only real gotcha be t' incorrect engine hook retainer measurement on t' instructions. Well, blow me down! Semroc makes it a breeze with all t' parts and laser-cut fins.

Overall Rating: 4 out o' 5

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