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, shiver me timbers, 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. Aye aye! Begad! I didn't think of it until I be deep into t' project. Begad! Ahoy! I downloaded t' original plans from Jim Z. There be a problem with t' scale when designin' t' parts. Aye aye! T' 4" tubin' scaled out t' 4.16x while t' 3" tubin' scaled t' 4.10x. Most of the rocket be designed usin' t' 4.16x scale. Some o' t' parts had t' be 4.10x while I compromised in some places usin' 4.13x. Begad! This kept t' whole package as proportionally close t' t' original as possible.

I waited until t' last possible moment t' chose t' motor size. Aye aye! I even painted most o' it before choosing. Begad! T' reason for this be weight. Aye aye! 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. Aye aye! Ahoy! I wanted t' choose a motor that would have enough power for a safe flight, arrr, but nay so much that t' g force would tear it apart. Begad! Each step o' t' way me thoughts were t' keep it as light as possible without sacrificin' strength. Avast, me proud beauty! Ya scallywag!

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

Scratch 4x Andromeda T' three rings on t' fin can act like exterior centerin' rings. Avast! Countin' these, shiver me timbers, 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". Begad! Ahoy! I tried t' compensate by ID fillets & epoxy rivets. 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, me hearties, ya bilge rat, all sides. All epoxy betwixt t' 4" and 3" tubes are 2 hour slow cure. Begad! In all, the fins are attached with 9 oz o' 2 hour epoxy. Ahoy! 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.

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

T' conduit dowels were secured t' t' main fins with a kind o' mortise and tennon thing. Avast! T' depth o' t' mortise is about 1 /1/2". Blimey!

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

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

T' three "coolin' rings" were painted white in t' '75 & '76 Estes catalogue. Avast! They were painted black in t' '77 through '82 catalogues. Well, blow me down! I opted t' paint them white t' add contrast in t' area.

Flight:
Well, I sent t' Andromeda up on a J350. Arrr! Blimey! Avast, me proud beauty! Blimey! It left t' pad with authority and flew perfect. It arched over at apogee and t' deployment came out perfectly timed. Begad! Blimey!

Recovery:
Wait... Aye aye! Ahoy! What's this? T' chute is tangled! T' darn thin' backward slid all the way in at a pretty good clip. Begad! (That's what 16 pound rockets do ya know.) It hit the ground with a thud. Ya scallywag! Begad! Nay pretty. With me heart stopped, shiver me timbers, and me stomach in my throat, I told me self "its only a rocket, ya bilge rat, arrr, 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. Well, blow me down! Ya scallywag!

Summary:
Wow! 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. Arrr! Blimey! Here is a video. Avast! It's a bit big at 2.3 megabytes.

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