Scratch Sprike Original Design / Scratch Built

Scratch - Sprike {Scratch}

Contributed by Greg Deeter

Manufacturer: Scratch

Rocket PicBrief:
This is a simple 3" single staged rocket which I scratch built over t' period o' a few days. T' rocket I used for me Tripoli L1 Certification was t' BSD Canadian Sprint (38mm motor version o' their 3" Sprint), which is a large upscale o' t' Estes Astron Sprint circa late 60's and early 70's. Avast, me proud beauty! Ahoy! Ever since I have retired that rocket due t' it's sentimental value, I have always missed flyin' it because it flew so nice. Ya scallywag! So I decided t' replace it with somethin' very similar but unique, for frequent simple H flights with very little prep needed.

Construction:

  • 3 - Elliptical fins (from BSD)
  • 1 - LOC 3" Airframe
  • 1 - 6:1 Fiberglass Conical -Spike Nose Cone from Curtis Turner
  • 1 - 38mm Motor Tube from LOC
  • 2 - 3" x 38mm Centerin' Rings from Quickburst.Net
  • 1 - 3" Bulkhead plate from Quickburst.Net
  • 1 - 38mm Giant Leap Slimline Bell Cone Retainer
  • 2 - Stainless Steel Quicklinks
  • 2 - Stainless Steel U-Bolts
  • 6 - Snap Rivits from Public Missiles
  • 2 - Delrin rail buttons from Railbuttons.Com
  • 1 - TAC-1 36" Chute from www.Motorman.US
  • 1 - Keelhaul®©™ Heat Shield from Quickburst.Net
  • 45 Feet o' Tubular Keelhaul®©™ from www.Motorman.US

Construction was quite simple and fast and I only used about 1 ounce o' epoxy on t' entire rocket. Aye aye! Avast! This be t' lightest 3" build I have ever done.

T' name Sprike be derived by Challenger 498 club member Chase Hrncir when he saw it in it's build phase. Begad! It's half Sprint / Half Spike (Same Nose Cone as a Polecat Spike), thus a "Sprike" . Ahoy! Aye aye! Sprike be also an item in t' classic video game Doom, shiver me timbers, and it is also a term related t' digital audio meanin' "Noise".

I started by removin' t' glassine layer from t' 38mm motor tube t' get some prime adhesion and used a tiny amount o' 28 minute epoxy t' seat t' centerin' rings onto t' motor tube. I then cut t' fin slots with a Dremel disk cutter, inserted t' motor tube yet used no glue at all t' hold it in. It fit very tight when test fittin' and I could never get it back out, so I simply inserted t' through t' wall fins with a small amount o' epoxy at their root edges t' t' motor tube. Avast! Blimey! I then epoxied t' bulkhead plate into t' coupler for t' payload bay and that's all t' glue I used on this rocket! Blimey! Less than 10 minutes workin' with epoxy, nay even a whole ounce and that be it. Ya scallywag! Blimey! I secured t' nose cone and payload bay with snap rivets from Public Missiles.

Lift-OffT' recovery system consists o' a Stainless Steel U-Bolt in t' fore motor mount centerin' ring, ya bilge rat, another Stainless Steel U-Bolt in t' bulkhead and everythin' is held together with 45 feet o' fireproof Tubular Keelhaul®©™, arrr, a few Stainless Steel Quick-links and a nice strong TAC-1 chute (protected by a Keelhaul®©™ Heat Shield) brings it all back safe.

I painted this rocket with a nice soft flat Satin Blue yet with that color bein' so close t' t' color o' t' sky I added a wrap o' adhesive backed chrome Mylar tape. Arrr! Begad! As you will see in t' launch photos that does real well at lightin' it up in t' sky by reflectin' off t' sun. Avast, me proud beauty! T' give a little color matchin' I painted t' nose cone with some chrome paint that rocket pal Tim Berg gave me before movin' t' Scotland. Ya scallywag! That came out real well too and it's a nice lookin' bird.

Flight:
T' first (test) flight be on September 11th 2005 at Rushin' Park in Katy Texas with t' Challenger 498 club. Avast, me proud beauty! It was a little windy but I really wanted t' launch it. Begad! Used a Cesaroni Pro38 G79SS Smokey Sam with t' delay manually set t' 6. Avast, me proud beauty! That was perfect for nailin' apogee deployment. Ya scallywag! Avast, me bucko, me proud beauty! Landed in a parkin' lot t' add some -character- t' me nice new paint job.

Second and third flights were this mornin' at NASA's Johnson Space Center. Well, blow me down! Blimey! This bird likes H motors. Well, blow me down! Blimey! Blimey! It flew just beautifully on an H153-8 and then an H143SS-8. Both delays were manually set with t' CTI tool but apogee deployment looked so perfect it was as if it were altimeter deploy. Ya scallywag! Blimey! And both times t' rocket recovered very close t' t' rail for some very short walks.

RecoverySummary:
This is a great flyer and I am quite pleased with it. Even with t' very small amount o' glue used in t' build it's strong as an ox. At some point in t' future I plan on addin' an electronics bay for dual deployments and lettin' her rip on some "I" motors like a LOKI Research I-405. Ya scallywag! Aye aye! And eventually I can see launchin' it with a nice tame CTI Pro38 J400SS. Arrr! :)

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