Difference between revisions of "User talk:Zombie Elvis"

Revision as of 19:37, 1 July 2015

Your contribution to thrust-to-weight ratio

Hi, thank you for your contributions. Two little things:

• I changed the name back to lower cased version: It should be clear what the letters TWR stand for. Also the English Wikipedia also uses the lowercased name: All acronyms are written with uppercased letters even when they originate from a lowercased word.
• I tried to make your “clumsy” sentence not so clumsy. I hope that I described it physically correct, but afaik the TWR is not important to “escape” a body (either by reaching escape velocity or leaving the sphere of influence). It is only important to land and start (but not for the complete landing and starting, the TWR is important as long as the craft has not enough time to (return to) orbit).

— xZise [talk] 04:07, 7 October 2013 (CDT)

Missunderstood change in 1.0

Hi in you mention drag before 1.0. That is true but not relevant for TWR. What is that the thrust depends on pressure and that changed with 1.0. Before 1.0 the fuel flow changed in reaction to a changing Isp but with 1.0 the fuel flow is fixed and the thrust changes to react to the changing Isp (both times with a fixed throttle). — xZise [talk] 10:27, 28 June 2015 (UTC)

You're right about the drag, but that's exactly what my edit said. Did you miss the "Before 1.0" right before your edit? You also changed it to a sentence fragment. Zombie Elvis (talk) 19:30, 29 June 2015 (UTC)

You mean this edit? No I did not miss it but the result is not similar with versions before 1.0. The fuel flow change (< 1.0), changes how much the TWR changes. The thrust change (>= 1.0), changes the TWR directly.

Also the fuel flow influences only the first point (changing the change in resource) while the thrust itself directly changes the TWR. So before 1.0 the TWR got greater because of lower mass but it got less greater during ascent as the engines used less fuel. Now the TWR gets greater as you ascent because the engines produce more and more thrust.

Alternatively you can say that the TWR itself is not depending on the altitude before version 1.0. Since 1.0 the TWR directly depends on altitude. — xZise [talk] 22:16, 29 June 2015 (UTC)

Uhhhh, fuel flow does too affect TWR. It did then and it still does. Don't believe me? Set your throttle to zero. What are your fuel flow and TWR now?

You still left a sentence fragment. Zombie Elvis (talk) 02:18, 30 June 2015 (UTC)

I am no idiot -.- Of course does throttling change the thrust output and oh wonder it's mentioned: “On most engines the thrust can be throttled, so lowering the thrust leads to a lower ratio than one calculated for full throttle.” Also, and this is important which 1.0 changed, the thrust changes independently from the throttle. I was always talking about the fuel fuel/thrust due to changing specific impulse which I also made clear in the article: “Before 1.0 the fuel flow changed instead [of the thrust due to the specific impulse] which did not directly affect the TWR and just changed the amount of resources which influences the change in TWR instead.” — xZise [talk] 19:37, 1 July 2015 (UTC)