Adiabatics

You or whoever made the post first stuck it "in my face" first so I shoved it back with equal and opposite force.

Bottom posting is the incorrect way to post on newsgroups. regardless of what any etiquette manuals try and say.

accepted is not the same as RIGHT.

I do not shove it in people's faces because it just results in arguments but when someone "rams it" in my face like that I feel the urge and need to shove back with equal and opposite force.

Chris Taylor

Where did you hear _that_??

-dave w

It's in Chris' forthcoming book, entitled

"I'm o.k., you're SO FULL OF S*IT it's not even FUNNY you are SUCH a MORON go ahead and PROVE I'm wrong you CAN'T cuz you are FULL OF IT and you KNOW it so BITE MY ASS."

ROFL

If the title is that long, I'll wait for the movie. ; )

Randy

I am humbled, you are truly a master smart Az.

Joel. phx

You are wrong. The point is that at fixed propellant mass, the temperature variation has an affect on ISP. There may or may not be as strong of an affect on total impulse, depending on the efficiency of the propellant. They are not interchangeable and do not necessarily have the same relation to temperature.

It is a natural consequence of a wide range of propellant formulas and not a choice of design.

You get today's "Mr. Obvious" award. ;)

-John

That's only the subtitle. You missed the big letters at the top of the book with the main title: "GRRRRR!"

It's in the series "Dummies for Dummies".

-john

That's right !! How did you guess.?

How Not to be a Dummy for Dummies.

You should buy copy #1

Chris Taylor

Delivered total impulse = the integral of delivered thrust over burn time.

Average delivered ISP = (the integral of delivered thrust over burn time)/propellant mass consumed.

Propellant mass is the same in both cases and mass in not affected by temperature. Everything that affects thrust over time affects Delivered total impulse and ISP the same.

Propellant formulas are most certainly one of many choices in motor design.

Thank you for agreeing with me. However, as you did not specify your simulations, and since Rocsim (which does not properly model or simulate the effects of initial temperature in motor performance) is the most commonly used sport rocketry simulator, I felt it was necessary to state the obvious so that less informed readers are not misled my your statements.

Alan

That's only the working title. At publication it will be called, "The workd according to Chris Taylor Jr.".

Chris, I agree with you 100%. And I'd like to compliment you on your explanation. It was very well thought out, formatted, and easily understood and readable.

thanks, steve

snipped for brevity

Ah, that little word "average". And you're the first to deride someone for being insufficiently pedantic. :)

As I said, it is not a design choice because the professional formulations with less of a temperature coefficient are not feasible for consumer rocketry.

If one were to do a simulation to determine temperature affects, why would one use a program that did not model that parameter? Hence, your award as "Mr. Obvious". We can now add "Mr Pedantic". But, I think you've earned the title here before. I think we've have to swap that crown back and forth once in a while. ;)

-John

Caution and completeness are essential in rocketry. I'll gladly wear those crowns, but not the cap you wear.

Alan

You should be cautious about your complete understanding of the subject at hand.

End of thread. Original questions have been answered.

-John

Yes please, end of thread. You have run out of ineffecive arguments to your missleading statements, and personal insults.

Alan

John Demar has an endless supply of crap.

well, now that we have the pleasantries out of the way, can I ask what rubbed who the wrong way? It seemed the first characterization was a compliment, or was it sarcasm?

rmr - not for the faint of heart

- iz

Alan J> >

No! What part of end of thread do you not understand? ;)

Well, I'm not the most pleasant easy going person on RMR, but I will admitt to having a cold, a bad shopping experiece, insufficent sleep and wine... Usualy I ignore discussions of this sort.

Alan