Double Checking My Rocket Equation

[Der Anfang]

No, not my rocket, just the equation for a rocket, namely the Saturn V. I am a little new to this math stuff in terms of science, so bare with me. First and foremost, to determine the total delta-v of a spacecraft, you must express it as: Delta-v = Effective Exhaust Velocity * log(total, fueled mass (wet) / final, drained (dry) mass).

The answer for the Saturn V I got was ~17,862 m/s delta-v. I am asuming that this is for the three stage assembly itself, not including the Lunar CSM.

Also, additionally, I decided to calculate the initial thrust of each stage for the SV, using the equation F(thrust) = Ve * (delta-m/delta-t), where delta-m is the flow of mass over delta-t, the time being in seconds. Ve is effective exhaust velocity (expressed as Isp in seconds * 9.81 m/s^2).

Specifics (based on some onlinep research):

Stage burn time

S1: 161 s

S2: 390 s

S3: 475 s

Stage masses

S1: Dry = 135 t, Wet = 2,286 t

S2: Dry = 39 t, wet = 490 t

S3: Dry = 13 t, wet = 119 t.

Stage Isp

S1: 265 s

S2: 200 s

S3: 200 s.

My math could be way off, and if so, tell me where I went wrong and what it should be. Based on those specifics, my results were as such:

S1: 46,751 kN

S2: 3,060 kN

S3: 491 kN.

I also tried to calculate the delta V of each stage chronically, but the numbers were way off and didn't add up to my 17.8 km/s delta-v result. (Admittedly, I don't really know what I am doing) I'm most likely a huge noob at this, but I am really curious... please help me.

Edited August 8, 2015 by Der Anfang

[MinimumSky5]

I don't know the specifics of the Saturn V, but an Isp of only 200s on stage 2 and 3 seems way too low, as they are hydrolox stages I would expect their Isp to be closer to 380-400.

[Kryten]

200 seconds is the sea level Isp for the J2s on the second and third stages, the Isp in practice would be much closer to the vacuum value of about 420 seconds.

[Der Anfang]

I don't know the specifics of the Saturn V, but an Isp of only 200s on stage 2 and 3 seems way too low, as they are hydrolox stages I would expect their Isp to be closer to 380-400.

http://www.astronautix.com/lvs/saturnv.htm

This is where I got the specifics.

[ElWanderer]

http://www.astronautix.com/lvs/saturnv.htm

This is where I got the specifics.

That says Isp 421s for the second and third stages. It also says Isp (sl): 200s, but the sea-level Isp is fairly meaningless considering the altitude at which those stages were ignited.