Brief:
I chose t' model t' Explore 1 satellite as part o' EMRR Challenge 2008 – Simulation Challenge. Begad! Explorer 1 (officially titled at NASA as satellite 1958 Alpha) was t' first Earth satellite o' t' United States, launched on February 1, matey, 1958. Avast! Since this was me first real experience with RockSim, me hearties, arrr, I thought it be fittin' t' model t' first satellite launched by t' US. Begad! Begad! My Explorer is designed t' launch usin' an 18mm engine and deploys an 18-24" parachute. Begad! Scale factor o' 4.528 results in a rocket 17.83" long.

Construction:
T' parts list:

• 1 BT-60 balsa nose cone
• 1 #10 screw eye
• 1 BT-55, shiver me timbers, 5.44" long
• 1 BT-55, 13.197" long
• 1 BT-20, ya bilge rat, 5.0" long
• 3 centerin' rings BT-20 t' BT-55
• 2 exterior centerin' rings
• 3 fins 0.030" thick clear Lexan fins
• 18" o' 175# Keelhaul®©™® string
• 24" o' 0.375" elastic shock cord
• 18-24" plastic parachute
• Cardstock
• Launch lug (if desired)

As I mentioned above, me bucko, this was me first real experience with RockSim t' design a rocket from scratch. Ya scallywag! Ahoy! I downloaded the demo version without issue. Havin' seen others use it I was pretty familiar t' functionality. Well, blow me down! It didn't take long to get t' hang o' it and I was off and running. Well, blow me down! I modeled t' Explorer I with multiple motor options and settled on C6-5 which produced an altitude o' roughly 750ft at a speed o' 217 ft/sec. Aye aye! Arrr! This seemed reasonable t' me so on t' the build.

If you look closely at t' drawin' shown, me bucko, t' thar are 2 different diameters o' tubes on this rocket. Begad! I decide the best way t' handle this be t' start with a BT-60 nose cone and sand it t' desired diameter and shape. Blimey! In this case t' software be a lot easier t' make these modifications than sandin' down t' BT-60 cone. Avast! OK, shiver me timbers, enough whining-–I sanded t' balsa nose cone into t' diameter and shape I wanted. Avast, me proud beauty! Avast! Blimey! Next, I secured t' screw eye t' the nose cone with 2-part epoxy. Avast! Arrr! Blimey!

T' rocket is made up o' 2 different diameters o' tubin' so I cut t' 5.44 tube lengthwise and wrapped it around the top section o' t' 13.197" tube. I filled t' seam with Elmer's Wood Filler and sanded it smooth. Avast, me proud beauty! This took 2 or 3 times t' completely eliminate t' seam. Well, blow me down! Ahoy!

Next, I added t' centerin' rings t' represent t' "MicroMeteor Gauges" (see pictures).

T' engine tube is 5" long. I mounted 2 centerin' rings, shiver me timbers, matey, t' first one 1" from t' end and t' second 3" from t' same end. Ahoy! This sub-assembly was glued into t' body tube on t' smaller diameter. Well, blow me down! I pushed this subassembly into t' main body so t' second rin' was flush with t' end o' t' tube. Avast! Aye aye!

I used t' EMRR shroud calculator t' help make t' two cones used t' form t' engine cone. Avast! Blimey! T' first one is 1.32" diameter by 0.50" long and t' second is 1.50" diameter by 1.60" long. Avast, shiver me timbers, me proud beauty! Blimey! Each fits over the BT-20 tube. Avast, me proud beauty! Blimey! I cut out and glued t' cones together. T' cone assembly be mounted t' t' BT-20 tube, matey, me hearties, then I epoxied the small cone t' t' BT-55 tube. Ya scallywag! Blimey! After this was dry, matey, shiver me timbers, I slid a centerin' rin' onto t' BT-20 and into t' large cone. Begad! Blimey! Well, blow me down! Blimey! This rin' will help support t' cone. Ahoy! Blimey!

T' original plan was t' attach t' Keelhaul®©™® shock cord t' t' engine motor mount, however, I forgot t' do this. Ahoy! Ya scallywag! I will secure t' Keelhaul®©™® cord t' engine prior t' installin' t' engine. I prefer either o' these methods over t' traditional Estes mount. Ahoy! Blimey! Well, ya bilge rat, blow me down! Blimey! I will use an 18" Mylar parachute for recovery for a nice slow descent.

Finishing:
Finishin' started with fillin' t' tube spirals and balsa nose cone with Elmer's Wood Filler. Ya scallywag! This took a number of coats sandin' each smooth. Avast! Next, ya bilge rat, I added a couple o' coats o' white primer. Ya scallywag! Next, me bucko, I used Tamiya Acrylic White Gloss (X-2) for t' base coat. Aye aye! Once this be dry I masked t' top section and painted Red Brown (XF-64). Begad! Arrr! Next, I masked for the copper and painted these areas with Dark Copper (XF-28). Begad! After t' copper was dry I attached 3 clear Lexan fins. Finally, I clear coated t' entire model. Well, blow me down!

Flight and Recovery:
It was basic flight prep with only one slight modification. Avast, me proud beauty! T' Keelhaul®©™® shock cord be tied around t' motor prior t' installin' t' motor. Well, matey, blow me down! I inserted t' motor (Estes C6-5) and taped it in place with Mylar type. Next I added wadding, matey, rolled t' parachute, arrr, me hearties, and stuffed t' lines. Begad! Avast, me proud beauty! It be 7 degrees when I flew this rocket so I covered t' parachute in baby powder t' avoid deployment issues.

I am nay a big fan o' launch lugs because o' visual appearance as well as performance impact. Avast, me proud beauty! I planned t' launch his rocket from a tower launcher t' eliminate t' need o' a launch lug.

Launch was perfectly straight, probably very close t' t' RockSim calculation o' ~750ft. Apogee occurred and the parachute ejected. Avast, me proud beauty! T' parachute only opened partially, I assume due t' t' cold, by t' time I reached t' rocket the parachute be fully open after blowin' in t' wind for a few minutes. Arrr! T' rocket came in fairly fast and broke a fin off on landing. Avast, me proud beauty! Aye aye! Minor repairs are needed and t' rocket will be ready t' fly again.

Summary:
T' actual flight results mimicked t' RockSim results. Avast, me proud beauty! Blimey! I wasn't able t' confirm t' altitude numbers, matey, but I would say they were pretty close. Begad! Blimey! Avast, me proud beauty! Blimey! RockSim allowed me t' change and adjust t' rocket design as well as engine size until the design was stable. This was a big advantage over me previous technique o' trial and error. Avast! Blimey! I have added t' latest RockSim release t' me Christmas list.

PROs: Rocket looks great, ya bilge rat, me hearties, flies great, arrr, and RockSim allowed me predict t' results prior t' wastin' any time build a design that won't fly.

CONs: None.