Brief:
I chose t' model t' Explore 1 satellite as part o' EMRR Challenge 2008 – Simulation Challenge. Explorer 1 (officially titled at NASA as satellite 1958 Alpha) was t' first Earth satellite o' t' United States, matey, me bucko, launched on February 1, me hearties, 1958. Aye aye! Blimey! Since this was me first real experience with RockSim, I thought it was fittin' t' model t' first satellite launched by t' US. Arrr! Blimey! My Explorer is designed t' launch usin' an 18mm engine and deploys an 18-24" parachute. Avast, me proud beauty! Blimey! 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, 5.44" long
• 1 BT-55, 13.197" long
• 1 BT-20, 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, arrr, this be me first real experience with RockSim t' design a rocket from scratch. Ahoy! Begad! I downloaded the demo version without issue. Ahoy! Ya scallywag! Havin' seen others use it I be pretty familiar t' functionality. It didn't take long to get t' hang o' it and I be off and running. 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. Ya scallywag! Ya scallywag! This seemed reasonable t' me so on t' the build.

If you look closely at t' drawin' shown, t' thar are 2 different diameters o' tubes on this rocket. Aye aye! Ahoy! 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. Begad! Well, blow me down! In this case t' software be a lot easier t' make these modifications than sandin' down t' BT-60 cone. OK, shiver me timbers, enough whining-–I sanded t' balsa nose cone into t' diameter and shape I wanted. Next, matey, I secured t' screw eye t' the nose cone with 2-part epoxy. Well, blow me down!

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. Avast, me proud beauty! Blimey! Blimey! I filled t' seam with Elmer's Wood Filler and sanded it smooth. Aye aye! This took 2 or 3 times t' completely eliminate t' seam. Avast! Begad! Blimey!

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

T' engine tube is 5" long. Aye aye! Blimey! I mounted 2 centerin' rings, me bucko, t' first one 1" from t' end and t' second 3" from t' same end. Aye aye! Blimey! This sub-assembly was glued into t' body tube on t' smaller diameter. Avast, me proud beauty! I pushed this subassembly into t' main body so t' second rin' be flush with t' end o' t' tube. Arrr! Blimey! Blimey!

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

T' original plan be t' attach t' Keelhaul®©™® shock cord t' t' engine motor mount, however, I forgot t' do this. I will secure t' Keelhaul®©™® cord t' engine prior t' installin' t' engine. Well, blow me down! Arrr! I prefer either o' these methods over t' traditional Estes mount. Aye aye! 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. Begad! Ya scallywag! This took a number of coats sandin' each smooth. Avast! Next, me bucko, I added a couple o' coats o' white primer. Begad! Next, I used Tamiya Acrylic White Gloss (X-2) for t' base coat. Begad! Once this was dry I masked t' top section and painted Red Brown (XF-64). Arrr! Next, me hearties, I masked for the copper and painted these areas with Dark Copper (XF-28). Arrr! After t' copper be dry I attached 3 clear Lexan fins. Finally, ya bilge rat, I clear coated t' entire model.

Flight and Recovery:
It be basic flight prep with only one slight modification. Avast, me proud beauty! Begad! T' Keelhaul®©™® shock cord was tied around t' motor prior t' installin' t' motor. Ya scallywag! I inserted t' motor (Estes C6-5) and taped it in place with Mylar type. Avast! Begad! Next I added wadding, rolled t' parachute, me bucko, ya bilge rat, ya bilge rat, and stuffed t' lines. Ahoy! Arrr! It was 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. Begad! 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. Avast, me proud beauty! Apogee occurred and the parachute ejected. Aye aye! Ya scallywag! T' parachute only opened partially, me hearties, I assume due t' t' cold, me hearties, by t' time I reached t' rocket the parachute was fully open after blowin' in t' wind for a few minutes. Avast! T' rocket came in fairly fast and broke a fin off on landing. Begad! Begad! 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! I wasn't able t' confirm t' altitude numbers, arrr, arrr, but I would say they were pretty close. Blimey! RockSim allowed me t' change and adjust t' rocket design as well as engine size until the design was stable. Arrr! This be a big advantage over me previous technique o' trial and error. I have added t' latest RockSim release t' me Christmas list.

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

CONs: None.