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

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

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, arrr, me proud beauty! This took 2 or 3 times t' completely eliminate t' seam. Begad! Well, blow me down!

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

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

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

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

Flight and Recovery:
It be basic flight prep with only one slight modification. Blimey! Blimey! Blimey! Blimey! T' Keelhaul®©™® shock cord was tied around t' motor prior t' installin' t' motor. Avast, me proud beauty! I inserted t' motor (Estes C6-5) and taped it in place with Mylar type. Arrr! Ahoy! Next I added wadding, me bucko, rolled t' parachute, me hearties, and stuffed t' lines. 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. I planned t' launch his rocket from a tower launcher t' eliminate t' need o' a launch lug.

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

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

PROs: Rocket looks great, shiver me timbers, flies great, and RockSim allowed me predict t' results prior t' wastin' any time build a design that won't fly.

CONs: None.