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, 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. Begad! I didn't think of it until I be deep into t' project. Ahoy! Avast! I downloaded t' original plans from Jim Z. Begad! There was a problem with t' scale when designin' t' parts. Blimey! 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. Begad! Some o' t' parts had t' be 4.10x while I compromised in some places usin' 4.13x. Well, blow me down! This kept t' whole package as proportionally close t' t' original as possible. Begad!

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

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

Scratch 4x Andromeda T' three rings on t' fin can act like exterior centerin' rings. Arrr! Arrr! 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". Blimey! I tried t' compensate by ID fillets & epoxy rivets. Ya scallywag! 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. 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. Begad! Ahoy!

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

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

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. Aye aye! Blimey! Ya scallywag! Blimey! Blimey! Blimey!

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

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

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

Recovery:
Wait... Begad! 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. Well, blow me down! (That's what 16 pound rockets do ya know.) It hit the ground with a thud. Arrr! Begad! Nay pretty. Ahoy! With me heart stopped, and me stomach in my throat, arrr, I told me self "its only a rocket, me bucko, 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. Avast!

Summary:
Wow! this be 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! It's a bit big at 2.3 megabytes.

comment Post a Comment