dhall_polo
Well Known Member
GPS2TAS:
http://itunes.apple.com/us/app/gps2tas/id381224165?mt=8
I was inspired by some recent threads from brantel and others to do some additional checks of my airspeed indication. I wasn't quite hitting vans numbers, and I was so sure I'd built a clean plane. After doing the calcs, it looks like my indicators are low, and I'm right on vans numbers. Now my next step is to fiddle with my safeair static port to see if I can increase accuracy. Anyway, there's a lot of great info in the forums about computing TAS from GPS track information, and I was able to find spreadsheets and online tools that can do the computations for you. I guess I'm impatient and didn't want to wait until I landed to get the TAS results, so what the heck, I decided to write iphone app number cajillion and one.
If you want to see how accurate your airspeed indicators are, just download this app (free) and bring it with you. It works just like the spreadsheets and online tools, requiring you to fly three legs and input your heading and groundspeeds. Once it has valid vectors, it computes TAS on the fly. It currently requires an iphone with the new v4 os. I'll upload a version that supports the older 3.x os when I can.
In putting the app together, all credit for the math goes to fellow RV'er, Doug Gray. I was able to reference algorithms published by Doug more than a dozen years ago, located here: http://www.kilohotel.com/rv8/rvlinks...y/TAS_FNL4.pdf. Additional references are available on the NTPS site here, which also leverages Doug's work as the base. Here's a post that sums it the general topic of computing TAS from GPS data. Most of the links in that post are now invalid, but it's a start. If you have any issues, questions, or comments, please feel free to PM me.
http://itunes.apple.com/us/app/gps2tas/id381224165?mt=8
I was inspired by some recent threads from brantel and others to do some additional checks of my airspeed indication. I wasn't quite hitting vans numbers, and I was so sure I'd built a clean plane. After doing the calcs, it looks like my indicators are low, and I'm right on vans numbers. Now my next step is to fiddle with my safeair static port to see if I can increase accuracy. Anyway, there's a lot of great info in the forums about computing TAS from GPS track information, and I was able to find spreadsheets and online tools that can do the computations for you. I guess I'm impatient and didn't want to wait until I landed to get the TAS results, so what the heck, I decided to write iphone app number cajillion and one.
If you want to see how accurate your airspeed indicators are, just download this app (free) and bring it with you. It works just like the spreadsheets and online tools, requiring you to fly three legs and input your heading and groundspeeds. Once it has valid vectors, it computes TAS on the fly. It currently requires an iphone with the new v4 os. I'll upload a version that supports the older 3.x os when I can.
In putting the app together, all credit for the math goes to fellow RV'er, Doug Gray. I was able to reference algorithms published by Doug more than a dozen years ago, located here: http://www.kilohotel.com/rv8/rvlinks...y/TAS_FNL4.pdf. Additional references are available on the NTPS site here, which also leverages Doug's work as the base. Here's a post that sums it the general topic of computing TAS from GPS data. Most of the links in that post are now invalid, but it's a start. If you have any issues, questions, or comments, please feel free to PM me.
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