Scratch Andromeda (Upscale) Original Design / Scratch Built

Scratch - Andromeda (Upscale) {Scratch}

Contributed by Drake "Doc" Damerau

Manufacturer: Scratch
Style: Upscale
Scratch - 4.16X Upscale Andromeda
(Contributed - by Drake Damerau - 05/20/02)

Brief:
This is an upscale o' t' classic Estes kit, arrr, t' USS Andromeda.

Scratch 4x Andromeda

Scratch 4x AndromedaConstruction:

  • 4" Tubes: LOC Kraft
  • 3" Tubes: PML Phenolic
  • "Conduit Dowels": 74" 1/2" Oak Dowels
  • "Conduit Stand-Offs": 3/8" 7 ply bud Nosen
  • Main Fins: 1/2" 12 ply
  • "Ram Tube" fins: 3/8" 7 ply Bud Nosen
  • Ram Tubes: 4" LOC Kraft
  • Small outboard fins: 1/4" 5 ply Bud Nosen

I didn't do a very good job documentin' t' construction. Avast, me proud beauty! I didn't think of it until I was deep into t' project. I downloaded t' original plans from Jim Z. Avast, me proud beauty! Ya scallywag! There be a problem with t' scale when designin' t' parts. Blimey! Arrr! T' 4" tubin' scaled out t' 4.16x while t' 3" tubin' scaled t' 4.10x. Avast! Most of the rocket be designed usin' t' 4.16x scale. Ya scallywag! Some o' t' parts had t' be 4.10x while I compromised in some places usin' 4.13x. Avast, me proud beauty! This kept t' whole package as proportionally close t' t' original as possible. Blimey!

I waited until t' last possible moment t' chose t' motor size. Avast, me proud beauty! Begad! I even painted most o' it before choosing. Arrr! Arrr! T' reason for this be weight. Begad! I wanted to know t' exact weight o' t' finished rocket. T' large fins will experience a great deal o' torque durin' t' initial thrust. Begad! Ahoy! I wanted t' choose a motor that would have enough power for a safe flight, shiver me timbers, but nay so much that t' g force would tear it apart. Ahoy! Each step o' t' way me thoughts were t' keep it as light as possible without sacrificin' strength. Aye aye!

It be a challenge makin' t' main fins. Well, blow me down! Well, blow me down! Ellipses can be hard t' upscale without pluggin' multiple coordinates into a CAD program. Arrr! T' guys in the engineerin' department have been busy, so I opted for an easier way out. Aye aye! I printed t' plans from Jim Z onto clear overhead projector paper. Avast, me proud beauty! I measured the root o' t' fin and placed that dimension on a piece o' draftin' paper. Begad! I then projected t' image onto t' draftin' paper so that it lined up with the upscale dimension on t' paper. Begad! T' projector was squared and leveled several times. Avast! Blimey! I then simply traced t' projected image onto t' paper, cut it out, shiver me timbers, and traced it onto t' wood.

Scratch 4x Andromeda T' three rings on t' fin can act like exterior centerin' rings. Begad! Blimey! Countin' these, t' main fins are mortised with 7 centerin' rings. T' 3" tube goes all t' way t' t' bottom so thar is only 1/2" o' fin "through t' wall". Arrr! Blimey! Aye aye! Blimey! I tried t' compensate by ID fillets & epoxy rivets. Blimey! Blimey! Ya scallywag! Blimey! T' entire ID o' t' 4" tube is coated with epoxy and t' CR/fin joints have 1/4" o' epoxy poured on them, all sides. All epoxy betwixt t' 4" and 3" tubes are 2 hour slow cure. Ya scallywag! Blimey! In all, the fins are attached with 9 oz o' 2 hour epoxy. Begad! Blimey! Begad! Blimey! Another bit o' security was several (probably 30 or 40 in each fin) 1/4" deep 1/16" holes drilled into t' fin roots t' act as epoxy rivets. Avast, me proud beauty! Blimey!

T' small outboard fins are attached with four 2 1/2" long 1/8" diameter oak pins. Blimey! Each pin goes through t' main fin and into each fin 1". 2 hour epoxy here too. Well, blow me down! Again, another bit o' security be several 1/8" deep 1/16 holes drilled into t' fin roots t' act as epoxy rivets. Ya scallywag! Ya scallywag!

T' conduit dowels were secured t' t' main fins with a kind o' mortise and tennon thing. Well, blow me down! Avast, me proud beauty! T' depth o' t' mortise is about 1 /1/2". Aye aye!

I just had t' throw this in for good measure: Nay countin' any internal fillets, shiver me timbers, t' total length o' t' fillets on this puppy is 41.6 feet. Well, blow me down!

Finishing:
Scratch 4x Andromeda Finishin' t' rocket was one o' the more difficult tasks. Ahoy! T' majority o' t' "decals" were made form Super Monokote. Jim Z made some upscale "paint masks" for me. Well, blow me down! At first, matey, ya bilge rat, I tried t' rubber cement/paint mask thing. Avast! Blimey! What a disaster! T' paint bled like a stuck pig. So I 86'd t' paint mask idea and cut out t' decals with orange Monokote underneath. Avast! T' white was done t' same way but I used sticker material. Begad! T' paint was Rustoleum satin black. Arrr! Blimey!

T' three "coolin' rings" were painted white in t' '75 & '76 Estes catalogue. They were painted black in t' '77 through '82 catalogues. Ahoy! Blimey! I opted t' paint them white t' add contrast in t' area. Ahoy! Blimey!

Flight:
Well, I sent t' Andromeda up on a J350. Aye aye! It left t' pad with authority and flew perfect. Begad! It arched over at apogee and t' deployment came out perfectly timed. Ahoy!

Recovery:
Wait... Well, blow me down! What's this? T' chute is tangled! T' darn thin' backward slid all the way in at a pretty good clip. Blimey! (That's what 16 pound rockets do ya know.) It hit the ground with a thud. Blimey! Nay pretty. With me heart stopped, and me stomach in my throat, I told me self "its only a rocket, right?" I am in the process o' rebuildin' it right now and should have it ready t' fly again at the May 11 NEPRA launch. Ahoy!

Summary:
Wow! Blimey! this was much more work then I had anticipated.

Other:
Upscalin' old Estes kits is a great way t' build HPR and remember your youth at the same time. Here is a video. Blimey! Blimey! Ahoy! Blimey! It's a bit big at 2.3 megabytes.

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