Timeline for Why is there a difference between GPS Speed and Indicator speed?
Current License: CC BY-SA 4.0
21 events
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| Apr 28, 2021 at 20:55 | history | edited | quiet flyer | CC BY-SA 4.0 |
fix typo
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| Oct 13, 2014 at 18:15 | comment | added | DeltaLima♦ | @rbp The change of dynamic pressure with both speed and density and compressibility effects at high speed are all aerodynamic effects. | |
| Oct 13, 2014 at 18:12 | comment | added | rbp | what is the aerodynamic effect? | |
| Oct 13, 2014 at 17:44 | comment | added | DeltaLima♦ | @rbp I (the original author) approved your edits only partially, and edited them to keep the original flow of reasoning. I could also have rejected them and then edit in the parts that I agreed with but I thought it was fairer to reward your efforts by accepting the edit. The difference between ground speed and indicated air speed is indeed because they are measured differently and that has everything to do with wind and aerodynamic effects. I purposely mentioned these two components in the first paragraph and expanded on them in the paragraphs below. | |
| Oct 13, 2014 at 17:27 | comment | added | rbp | GPS speed and the ASI show different values due to how they are measured, and has nothing to do with "wind and aerodynamic effects." I made the edit, and it has been changed back by the original author, even after being approved. | |
| S Oct 13, 2014 at 16:01 | history | edited | DeltaLima♦ | CC BY-SA 3.0 |
deleted 184 characters in body
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| S Oct 13, 2014 at 16:01 | history | suggested | rbp | CC BY-SA 3.0 |
clarified airspeed definitions, separated math into a technical section
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| Oct 13, 2014 at 15:29 | review | Suggested edits | |||
| S Oct 13, 2014 at 16:01 | |||||
| Jun 1, 2014 at 12:10 | vote | accept | Super Hornet | ||
| May 29, 2014 at 15:41 | comment | added | darthbith | $q_c$ is also known as dynamic pressure. | |
| May 29, 2014 at 9:27 | comment | added | DeltaLima♦ | @DavidZhang these are $\tfrac{\gamma}{\gamma - 1}$ and t $\tfrac{\gamma -1 }{\gamma}$. $\gamma$ is the ratio of specific heats which is assumed to be 1.4 for air. | |
| May 29, 2014 at 7:04 | comment | added | David Zhang | As a physics student, those exponents of $7/2$ and $2/7$ are very interesting. Do you care to explain how they arise? | |
| May 28, 2014 at 16:20 | comment | added | Lnafziger | @dvnrrs It may be nice to break the answer into two parts. One for more casual users and one for more technical users/people who want to keep reading. That being said, I don't think that this is too bad as it is. | |
| May 28, 2014 at 15:26 | history | edited | DeltaLima♦ | CC BY-SA 3.0 |
added 12 characters in body
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| May 28, 2014 at 15:26 | comment | added | Jason C | @dvnrrs No! Please do not skip the math and explanation. Even though it's more than what was asked for it's relevant, useful, and fascinating, and (as usual on aviation.sx) I learned an answer to a question I didn't even know I had. Definitely filing this one away for reference. | |
| May 28, 2014 at 14:41 | history | edited | DeltaLima♦ | CC BY-SA 3.0 |
added 55 characters in body
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| May 28, 2014 at 14:17 | comment | added | TypeIA | You definitely put a lot of effort into it, and it's great information for someone who is interested in that level of detail. For the context of this question though, I think the math should be skipped entirely, and the answer presented instead from a standpoint of what a typical pilot would know or need to know. Links to the more advanced stuff can always be provided for interested readers. Just my thoughts! | |
| May 28, 2014 at 14:12 | comment | added | DeltaLima♦ | @dvnrrs I tried to write it in such way that when you skip over the formulas the basic concept still comes across. I included numerical values to illustrate the effects described in the formulas and included text blocks that explain what is happening. | |
| May 28, 2014 at 14:02 | comment | added | TypeIA | Very thorough answer, but I feel it's too advanced and math-heavy, unnecessary for a casual enthusiast (or even for a professional pilot). It reads more like an aerodynamics textbook than a conceptual overview. | |
| May 28, 2014 at 12:29 | history | edited | DeltaLima♦ | CC BY-SA 3.0 |
added 33 characters in body
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| May 28, 2014 at 11:51 | history | answered | DeltaLima♦ | CC BY-SA 3.0 |