Brad Guth's Credentials
You've GOT to be kidding! lol. Is F=ma worn out too? hahaha...
This has GOT to be a joke. Really.
A disinformation tactic!? Those who know laugh, those who don't know
are confused or they actually believe the bull****.
sigh
ROCKET EQUATON
Figure out how fast a rocket stage will go knowing only the exhaust
speed of the rocket and the fraction of propellant.
Vf = Ve * LN(1/(1-u)) is still useful, despite your asinine
bull**** here.
Vf = final velocity of a rocket propelled projectile
Ve = exhaust velocity of the gases coming out of the engine
LN(..) = natural logarithm (base 'e')
u = propellant fractoin (a number between 0 (empty) and 1 (all
propellant)
Typical numbers;
ADVANCED ROCKETS
Solar/laser sail - infinity (no propellant)
Fusion pulse - 100,000 m/s
Ion - 50,000 m/s
Orion Nuclear Pulse -20,000 m/s (effective)
Nuclear thermal - 8,500 m/s
STATE OF ART ROCKETS
LOX/LH2 - 4,200 m/s
LOX/RP1 - 3,000 m/s
Hypergolic - 2,800 m/s
SRB - 2,200 m/s
H2O2 - 1,800 m/s
Nitrogen - 1,500 m/s
THRUST CALCULATION
F = mdot * Ve
F = thrust (Newtons)
mdot = mass flow rate
Ve = exhaust velocity
POWER CALCULATION
P = 1/2 * mdot * Ve^2
Power = watts
mdot = mass flow rate
Ve = exhaust velocity
FRACTIONS
1 = p + s + u
p = payload
s = structure
u = propellant
Typical values for s range from 0.08 to 0.22 depending on details like
thermal protection systems, and so forth.
THRUST TO WEIGHT
The thrust to weight of a typical chemical rocket is around 70 to 1.
That is for each pound or kg of mass you have 70 pounds or kgs of
thrust. But nuclear thermal rockets have a thrust to weight of about
20 to 1 at best. And nuclear pulse rockets like Orion are likely to
have a 5 to 1 thrust to weight. Ion rockets have 1/10,000 to 1 - they
cannot lift off earth. Fusion pulse rockets that have high performance
have very high captue of reaction products which means a very large
thrust structure, so they are likely not to have high thrust to weight.
Since no one has built these systems before there is a disagreement
about what they might achieve. Studies with thrust to weight from 2 to
1 down to 1/3 to 1 have been produced. The 2 to 1 can be used on
Earth. The 1/3 to 1 cannot, but can be used on the moon and mars.
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