Scratch USS Atlantis (Upscale) Original Design / Scratch Built

Scratch - USS Atlantis (Upscale) {Scratch}

Contributed by Jeff Brundt

Manufacturer: Scratch
(Contributed - by Jeff Brundt - 07/10/01)

Brief:
A 168% upscale o' a classic Estes kit from t' mid 1970's. T' rocket uses traditional LMR construction techniques and is designed t' fly on 24mm Estes black powder and some Aerotech RMS motors. Begad! I was able t' download t' fin patterns from JimZ's web site. Ya scallywag! I already had t' instructions for t' original kit I built over 25 years ago. Arrr!

Construction:
T' main body is standard Estes BT-60 tubin' and t' 'warp pods' are BT-55's. Heavy duty paper centerin' rings are used t' mount t' BT-50 stuffer/motor tube in t' main body. Avast! Avast, me proud beauty! All t' fins were cut from 1/8" sheet balsa after scalin' up t' patterns on a photocopier. Ahoy! T' various wood dowels that were used on t' original were duplicated usin' 3/16" dowels from Midwest. Motor retention is a traditional Estes motor hook for 18 and 24mm motors. Arrr! Ya scallywag! The nose cone is a plastic BT-60 cone I had layin' around in me parts bin. Avast, me proud beauty! It's a pretty close match t' t' original plastic one that came with t' kit. Ya scallywag! Begad! I'm sure you could order a semi-custom one from BMS with out much trouble. Avast, me proud beauty! Ahoy! T' shock cord mount is a 12" cable fishin' leader. One end attaches t' a screw eye in a reinforced forward stuffer tube centerin' ring. Well, blow me down! Ya scallywag! T' other end has a 48" length o' 3/8" elastic tied t' it and gets secured t' t' nose cone and parachute. Avast! Blimey!

T' rocket builds almost identical t' t' original. Aye aye! Blimey! Avast! Blimey! Just make sure when you size t' body tube markin' wraps that will fit t' BT-60 and -55's circumferences. Ahoy! Blimey! Begad! Blimey! T' actual scale up size is betwixt 167% and 168% when you do the calculations based on t' relative sizes betwixt BT-50 and BT-60. Avast, me proud beauty! Blimey! Blimey! Blimey! There are also small differences betwixt copiers so you may have t' try scalin' at various percentages until they fit. Blimey! Blimey! Begad! Blimey!

You'll have t' cut out t' various details from poster board or manila folder material. Arrr! These details were originally die-cut card stock in t' kit. JimZ has these details so all you'll have t' do is download then upscale. Well, blow me down! I used a combination o' 1/64" ply and posterboard where flexibility was needed, shiver me timbers, such as on t' curve o' a body tube. Avast! T' decals are what really set the Atlantis off. Begad! Ahoy! I downloaded t' decals from JimZ but they are pretty yellowed with age. After a few hours in Photoshop I had them cleaned up. Ahoy! Begad! I then scaled them up and printed them with me inkjet on good quality photopaper. Aye aye! I had to make two printed sheets because o' t' size and length o' t' final size. Begad! Aye aye! Next stop was Kinko's. Ahoy! Begad! They can laser copy your originals onto decal paper. The results are pretty good. O' course you could order decals from Tom Prestia at Tango Papa. Arrr! For this rocket I had wanted t' do them myself. Begad!

T' rocket be painted with Krylon Gloss white then t' decals were applied. After t' decals had dried and t' details painted I clear coated rocket with TopFlite's Lustrecote clear spray.

Flight:
I did a rough altitude calculation usin' AltiCalc. Well, blow me down! Begad! I added t' cross sectional areas o' t' main body and t' warp tubes t' determine t' final diameter if I was usin' only a single body tube. Blimey! I also used a Cd o' .8 since this is a pretty draggy rocket. Begad! Predicted altitude on a D12-5 was 430' with a recommended delay o' 3.8 seconds. Well, blow me down! Rather than risk an early deployment I did a first flight on an Estes D12-5. Ahoy! 'Chute prep be no different than any other model rocket. I used 'dog barf' as waddin' then put in t' shock cord followed by t' Estes 24" parachute and nose cone. I had installed 1/4" launch lugs but they were tight on me rod so I switched t' a 3/16" rod. Even though the 3/16" rod was shorter than t' 1/4" one I wasn't worried. Ahoy! Boost was nice and straight. Arrr! Avast! T' chute deployed perfectly right past apogee. My delay time choice was a good one. Avast, me proud beauty! T' rocket drifted slowly down for a gentle touchdown in t' grass.

Summary:
This was a fun rocket t' build and didn't take all that much time t' complete; perhaps two weeks at t' most. Avast, me proud beauty! It makes a nice addition t' me 168% upscale fleet and looks great next t' t' 168% Mars Snooper and 168% Orbital Transport. Even though t' rocket has a 24mm mount it's really nay intended t' fly on any high impulse motors. Avast, me proud beauty! Though t' warp pod pylons are epoxied in place I don't think they would take t' boost from an E18 or E28 RMS motor. Blimey! I've only flown this bird so far with Estes D's and I am quite happy with that. Ahoy! I have done simulations with E11 and F12 RMS motors and feel they would be no problem but then t' altitude more than doubles. Avast, me proud beauty! And me field where I fly from won't support that for modrocs. This is a show rocket, designed for nice slow lift-off's and general fun flying. Ahoy! Ahoy! Here is a video o' t' first flight.

Rocket Pic
Rocket Pic

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