Centuri S.S.V. Scorpion

Centuri - S.S.V. Scorpion {Kit}

Contributed by Larry Zeilmann

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar
Manufacturer: Centuri

Centuri SSV ScorpionBrief:
Single stage model rocket that recovers with a dual parachutes in a unique level configuration.

Almost a year or more ago I downloaded t' instructions for Centuri's S.S.V. Avast, me proud beauty! Ya scallywag! Scorpion from t' JimZ web site. Arrr! Blimey! O' course I thought it was one o' the most impressive kits from t' Centuri Super Kit series. Ahoy! After reviewin' the instructions, ya bilge rat, I put them aside because a large portion o' t' kit was made from cut out poster board, me bucko, shiver me timbers, which was a process I was nay interested in duplicating at t' time. Begad! Nay until t' Master o' Oatlander Research Laboratories and fellow Classic Rocketeer challenged me t' try it did I finally return t' the instructions with a serious intent t' make an effort t' clone t' kit. Throughout t' process I was forced t' scratch build and substitute for items no longer available. Well, blow me down! I feel that I ended up with t' most challengin' cloned kit I have attempted and rewarded with me most satisfyin' results.

Construction:
Packaging? What packaging? Their ain't no stinkin' packaging. Ya scallywag! This is scratchbuildin' a clone.

Centuri SSV Scorpion First step is download t' very large instructions from JimZ's web site. Avast! All templates are included in t' instructions. Begad! I then visited t' local Hobby Lobby t' purchase some Picture mattin' board which is approximately .055" thick. Avast, me proud beauty! Well, blow me down! This is what I used t' cut most o' t' items from that were included in t' original fiber cards in t' kit. Arrr! Well, blow me down! Transferrin' t' shapes were accomplished with good old carbon paper. Below is a parts list and items used t' substitute. Begad!

  • 1 NC-56 Nose cone
  • 1 Plastic Connector (available from Moldin Oldies, me hearties, I scratchbuilt mine)
  • 2 ST-5 Body Tubes 2.5" (BT-5)
  • 1 ST-20 Body Tube 3.0" (BT-20 or Magnum "D" conversion with BT-50)
  • 1 ST-56 Body Tube 6.25" (BT-56 Red Arrow Hobbies or Totally Tubular)
  • 1 ST-56 Body Tube 7.0" (BT-56 Red Arrow Hobbies or Totally Tubular)
  • 1 ST-56 Body Tube 8.0" (BT-56 Red Arrow Hobbies or Totally Tubular)
  • 1 ST-20 Body Tube 5.0" (BT-80 Split and trimmed t' t' correct diameter, matey, shiver me timbers, me hearties, explained later)
  • 1 Launch Lug .25" long, arrr, ya bilge rat, 5/16" diameter (Substituted a standard Estes Maxi Launch Lug)
  • 1 Launch Lug 8" long, 7/32" diameter
  • 1 Coupler HTC-13 (BT-56 Coupler Red Arrow Hobbies)
  • 1 TR-7 Thrust Rin' .4" long (Standard thrust rin' for 18mm Motor or substitute a 24mm thrust ring)
  • 3 TR-7 Thrust Rings 3/16" long (Trim 3 standard 18mm Thrust rings)
  • 1 EL-1 Engine lock (Standard Estes Engine Hook)
  • 2 Die-Cut Fiber Sheets .055" Thick (Picture Mattin' board or 1/16" balsa)
  • 1 Die-Cut Fiber Sheet 110lb (gloss cardstock)
  • 1 Shock Cord .125" x 38" (Available in your local sewin' aisle)
  • 2 20" Parachutes
  • 128" o' Shroud Line

Instructions are clear and easy t' follow. Well, blow me down! Blimey! T' most challengin' part is cuttin' all t' items from t' thick picture mattin' board. Ya scallywag! Blimey! Blimey! Blimey! After t' first two items were cut usin' a razor knife, me hand be sore and I knew I needed too explore an alternate method. Ahoy! Blimey! Blimey! Blimey! I ended up cuttin' everythin' out with a scroll saw and spiral blade. I then soaked all mattin' board parts in thin CA to stiffen them. After that I cleaned t' edges o' t' parts on a belt sander. Begad! Blimey! The instructions also suggest cuttin' these parts from 1/16 sheet balsa. Avast, me proud beauty! Blimey! I chose not t' use balsa because o' it's lack o' durability.

T' ST-20 offered another problem in that a good substitute be no longer available. Arrr! After a long effort o' lookin' for a substitute, I decided t' split a BT80 lengthwise and trim t' t' proper diameter. I was nay concerned about joinin' or hidin' t' seam because t' seam would join against t' wall o' the inner BT-56, arrr, and t' seam could be hidden underneath t' long 8" launch lug.

Speakin' o' 8" launch lug, that also proved t' be a problem. Launch lugs are easy t' get, ya bilge rat, shiver me timbers, but nay in 8" lengths. Avast, me proud beauty! Again Hobby Lobby t' the rescue. I purchased a pack o' 3/16" x .014 seamless aluminum tube in 12" lengths. Packs o' three cost $1.99 and are extremely light weight. Inside diameter works with an 1/8" launch rod. Aye aye! Blimey! Care in cuttin' will provide an excellent substitute.

T' rare plastic coupler is available from Moldin' Oldies, matey, or in me case I scratch built it along with t' baffle coupler from several BT-56 tube sections.

Centuri SSV ScorpionFinishing:
I though buildin' would be t' most difficult part o' clonin' this classic kit. Instead finishin' it was t' most difficult step in t' buildin' process. Avast, me proud beauty! I first sprayed every thin' with three coats o' a primer/sealer paint. My personal favorite is Kilz. I then sanded this before paintin' with a finishing color. Ahoy! Avast! I chose t' use bright yellow Krylon. Blimey! With all t' difficult hidden areas and complex designs, shiver me timbers, I found it very difficult t' get a good coatin' without exposin' myself t' runs. In t' end I used a full can and sanded a few embarrassin' runs away.

For decals, I printed me own on inkjet decal paper available from several vendors on t' internet. Ahoy! Avast, me proud beauty! Application again proved challengin' because when workin' with large decals care is needed t' avoid stretchin' o' t' decal. Stretchin' will result in color separation. Ahoy! However, arrr, big decals trap a lot of air and water that need t' be worked out. Thus t' dilemma, matey, me hearties, ya bilge rat, remove t' bubbles and risk stretchin' or accept t' occasional bubble and avoid t' stretchin' . Both issues can be minimized by keepin' t' application surface wet and blottin' t' bubbles away. Avast! Either way this proves t' be a very difficult task. Begad!

Construction Rating: 5 out o' 5

Flight:
T' original kit calls for a C5-3 or C6-3. Avast, me proud beauty! An original kit owner informed me that t' original be very anemic on a C6-3, me bucko, and o' course t' C5-3 is no longer available. Begad! Aye aye! Therefore, me hearties, I did what I be informed was called a "Magnum D" conversion. Ahoy! Since me finished kit weighed in at 8.7 ounces, it is scheduled t' fly on a D12-3.

Preparation will be easy with t' built in Centuri baffle design. Ya scallywag! However I will add a few sheets o' waddin' t' protect against anythin' that might slip past t' baffle.

Motor retention is by t' standard Estes Engine hook.

Even though this rocket has yet t' fly, arrr, historically this design is reported by an original owner t' be extremely stable t' over stable. Well, blow me down! Data provided by t' same owner o' t' original kit shows that t' launch CG should fall at 21" aft o' t' nose cone tip.

Recovery:
Recovery harness is quite complex, and unique. Avast, me proud beauty! Begad! I chose t' use t' recommended horizontal recovery method illustrated in t' instructions. Avast! Begad! I did modify the "Variable Field Ringnet Unit" slightly. Well, blow me down! I cut a very small "v" slot in t' forward top edge t' accommodate t' recovery shroud line in t' launch configuration. Begad! I am hopin' this will prevent t' recovery shroud line from snaggin' any parts on deployment

Flight Rating: 5 out o' 5

Summary:
Overall, this is a great kit that with much effort will result in a great rocket. Well, blow me down! I am very happy with t' overall results.

Overall Rating: 5 out o' 5

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