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6 votes

How to calculate these engine parameters on my own?

Anton must really love chemistry or pain. NASA's CEA is a robust tool for analyzing combustion thermo-chemistry which was developed by the same Gordon & McBride mentioned in Anton's answer while ...
A McKelvy's user avatar
  • 2,492
5 votes
Accepted

Help on Nozzle Throat Area Calculation

I managed to reproduce your error. When it says "^1/2" in the equation, you are supposed to take the square root of the quantity in the parentheses. You are not doing this. You are dividing by 2 ...
Organic Marble's user avatar
5 votes

Issue with units for a rocket nozzle throat area problem

That equation as you give it with the values you supply is a bad mish-mash of units. It's painful to do this in the English system, but gather your courage, we can get through it. You must specify ...
Organic Marble's user avatar
4 votes
Accepted

Need clarification of units on rocket nozzle equation

I assume you're looking at the "original post" referenced in the linked post, and trying to work out the units. First of all, I'd strongly recommend you learn how to do this in SI units. ...
Darth Pseudonym's user avatar
3 votes
Accepted

Issue with units for a rocket nozzle throat area problem

$R$ and $g_c$ each have a foot component in their units; therefore the feet cancel out when $R$ is divided by $g_c$. $P_t$ is in pounds per square inch; since you're dividing by that, it's effectively ...
Russell Borogove's user avatar
3 votes
Accepted

How to calculate these engine parameters on my own?

You will need to write a solver for the incomplete combustion of your propellant. This can be done by hand, but I recommend writing a program to implement it. These days, such calculations are ...
Anton Hengst's user avatar
  • 10.8k
2 votes

Need help on rocket nozzle equation

The form of the gas constant used in that equation is not the universal gas constant. It is the gas constant for the particular gas under consideration. The value is obtained by dividing the universal ...
Organic Marble's user avatar
1 vote

Need clarification of units on rocket nozzle equation

Going back to the original question of how the units work out, this is how. The equation is $$A_t=\frac{w_t}{ P_t} \sqrt\frac{RT_t}{\gamma g_c}$$ Now $g_c$ is 32.2 ft-lbf/s$^2$-lbm (rounded numerical ...
W H G's user avatar
  • 706
1 vote

Problems with the "How to Design, Build and Test Small Liquid-Fuel Rocket Engines" text

One of the online versions of this book, the one found here, includes an "Additions and Corrections" page. The fifth bullet point on this page states: In the example calculation, I think there may ...
Organic Marble's user avatar

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