Scott,
I just downloaded Phred's Super Screamer RockSim file, and had no trouble at all reading it with version 7, which I got a few months ago.
With regard to parts, RockSim will give you part numbers only if such have been entered into the design database; I and many others use the default "Custom" designation when we insert nose cones, etc. that are not in the stock RockSim parts list. However, the dimensions are given, so you should have no trouble finding the part.
As far as telling you how it goes together, RockSim does not generate instructions, though it does show a very nice layout of the rocket, which is often a good enough guide for construction. It will generate fin patterns, transitions, and other such stuff. Here's a pic of the Super Screamer as it looks in RockSim (there is also a 3D view, where you can try out paint schemes and add decals):
And here's the parts list given by the program:
Sustainer parts
Nose cone - Custom, Material: Polystyrene PS
Nose shape: Hollow Ogive, Len: 10.500 In., Dia: 2.600 In.
Wall thickness: 0.020 In.
Body insert: OD: 2.540 In., Len: 1.250 In.
CG: 7.538 In. , Mass: 0.871 oz.
Radius of gyration: 0.095284151086 (m) , 9.528415 (cm)
Moment of inertia: 0.000224267331 (kgm^2) , 2242.673311 (gcm^2)
Body tube Estes - EST 3090 - BT-80, Material: Paper
OD: 2.600 In. , ID: 2.588 In. , Len: 24.500 In.
CG: 12.250 In. , Mass: 0.777 oz.
Radius of gyration: 0.181350451891 (m) , 18.135045 (cm)
Moment of inertia: 0.000724400453 (kgm^2) , 7244.004531 (gcm^2)
Foil lined 24mm motor mount tube Estes - EST 3086 - BT-50, Material: Paper
OD: 0.990 In. , ID: 0.950 In. , Len: 15.000 In.
Location: 0.000 In. From the base of Body tube
CG: 7.500 In. , Mass: 0.593 oz.
Radius of gyration: 0.110453945024 (m) , 11.045395 (cm)
Moment of inertia: 0.000204939352 (kgm^2) , 2049.393516 (gcm^2)
'E' Engine hook Estes - Engine hook - Standard size, Material:
CG: 0.000 In. , Mass: 0.053 oz.
Radius of gyration: 0.000000000000 (m) , 0.000000 (cm)
Moment of inertia: 0.000000000000 (kgm^2) , 0.000000 (gcm^2)
'E' Engine hook Estes - Engine hook - Standard size, Material:
CG: 0.000 In. , Mass: 0.053 oz.
Radius of gyration: 0.000000000000 (m) , 0.000000 (cm)
Moment of inertia: 0.000000000000 (kgm^2) , 0.000000 (gcm^2)
Engine block Apogee - 13031 - CR 18-24 ring, Material: Paper
Engine blockOD: 0.950 In., Len: 0.250 In.
Location: 3.500 In. From the base of Foil lined 24mm motor mount tube
CG: 0.125 In. , Mass: 0.045 oz.
Radius of gyration: 0.007872173203 (m) , 0.787217 (cm)
Moment of inertia: 0.000000079350 (kgm^2) , 0.793497 (gcm^2)
Ring - Custom, Material: 1/8 Aircraft Plywood
Centering ringOD: 2.588 In., ID: 0.990 In., Len: 0.125 In.
Location: 0.250 In. From the base of Body tube
CG: 0.063 In. , Mass: 0.110 oz.
Radius of gyration: 0.017638802620 (m) , 1.763880 (cm)
Moment of inertia: 0.000000966006 (kgm^2) , 9.660061 (gcm^2)
Ring - Custom, Material: 1/8 Aircraft Plywood
Centering ringOD: 2.588 In., ID: 0.990 In., Len: 0.125 In.
Location: 3.500 In. From the base of Body tube
CG: 0.063 In. , Mass: 0.110 oz.
Radius of gyration: 0.017638802620 (m) , 1.763880 (cm)
Moment of inertia: 0.000000966006 (kgm^2) , 9.660061 (gcm^2)
Ring - Custom, Material: 1/8 Aircraft Plywood
Centering ringOD: 2.588 In., ID: 0.990 In., Len: 0.125 In.
Location: 14.800 In. From the base of Body tube
CG: 0.063 In. , Mass: 0.110 oz.
Radius of gyration: 0.017638802620 (m) , 1.763880 (cm)
Moment of inertia: 0.000000966006 (kgm^2) , 9.660061 (gcm^2)
Custom Fin set - Custom, Material: Balsa
CG: 5.248 In. , Mass: 2.204 oz.
Radius of gyration: 0.071347304766 (m) , 7.134730 (cm)
Moment of inertia: 0.000318109019 (kgm^2) , 3181.090186 (gcm^2)
Parachute - Custom, Material: 1.3 oz. Ripstop Nylon (SkyAngle)
1 parachute, Shape: 8 sided
Dia: 28.506 In., Spill hole: 0.000 In.
CG: 2.376 In. , Mass: 0.008 oz.
Radius of gyration: 0.037276287766 (m) , 3.727629 (cm)
Moment of inertia: 0.000000322533 (kgm^2) , 3.225328 (gcm^2)
Bulkhead - Custom, Material: Aircraft plywood (Birch)
BulkheadOD: 2.588 In., Len: 0.125 In.
Location: 23.250 In. From the base of Body tube
CG: 0.063 In. , Mass: 0.276 oz.
Radius of gyration: 0.016477811638 (m) , 1.647781 (cm)
Moment of inertia: 0.000002121101 (kgm^2) , 21.211013 (gcm^2)
Eye Bolt Public Missiles - HDWE-EYE-1/8 - 1/8x24, Material: Steel
CG: 0.000 In. , Mass: 0.200 oz.
Radius of gyration: 0.000000000000 (m) , 0.000000 (cm)
Moment of inertia: 0.000000000000 (kgm^2) , 0.000000 (gcm^2)
Launch lug Estes - ESTES 2328 - LL-3/16, Material: paper
OD: 0.188 In., ID: 0.169 In., Len: 2.000 In., Loc: 15.000 In.
CG: 1.000 In. , Mass: 0.007 oz.
Radius of gyration: 0.014768527682 (m) , 1.476853 (cm)
Moment of inertia: 0.000000042118 (kgm^2) , 0.421178 (gcm^2)
I really like RockSim, which I now use for all my scratch builds. As with all rocket cad programs, it has its limits, but Bruce Levison here on TRF has developed ways to get around some of these. I do not think you will regret buying it.
That said, there is no Mac version - PC only, dude
