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Watch App: TruFlite Ballistics

jrjackson
over 6 years ago

This will be the support thread for my watch application: TruFlite Ballistics


TruFlite is an exterior ballistics program for long range shooting. It contains a highly accurate, yet stand alone ballistics engine that is extremely fast. Designed to not rely on connecting with a phone for data input or for calculations.

https://apps.garmin.com/en-US/apps/c8a08648-1344-4dd5-ac3d-6a54b165db5c


I will post release notes here as new versions are released as well as the main application page.

Feel free to post questions, comments, feature requests, or bug reports here or send me an email directly using Contact Developer

Operation:

OK/Select - Calculates a firing solution

UP/Previous - increase range by current range interval setting, default: 25 yards/meters

DOWN/Next - decrease range by current range interval setting

Menu -

Cross Wind - wind speed in mph/kph/mps. To keep input simpler just cross wind, not wind and direction.

Ambient Temp - Farenheit/Celcius, device temperature can be affected by body temperature so it is more accurate to provide one

Muzzle Velocity - launch velocity in fps/mps

BC - change the Ballistic Coefficient and select Drag Curve (G1 or G7). Assumed that BC is ICAO relative.

Sight Height - height of sights in inches/cm

Zero - range (yds/m) at which weapon was zero'd

Units - Allows changing units of any variable between metric or imperial individually.

Options - Change Range Interval and Turn on/off use of external Tempe temperature sensor

About - Get to current version number


Units / Elevation Units - units for Elevation correction to be displayed in: inches, cm, moa, mils

Units / Windage Units - units for Windage correction to be displayed in: inches, cm, moa, mils

....

When calculating a firing solution, TruFlite uses the current Ambient Barometric Pressure from the device's raw sensor in order to provide the most accurate solution for your current environment. This value is displayed just above the firing solution and will be displayed in green, indicated the value came from a sensor. For slightly older devices that do not allow applications direct access to the raw pressure sensor, the device altitude is used to calculate current pressure. Temperature is manually inputted or retrieved from an external sensor, since the internal temperature sensor of the watch is affected by body temperature and therefore provides an inaccurate ambient temperature.

If you have a Garmin Tempe Temperature sensor and wish to use it with TruFlite, simply follow the standard instructions for pairing the sensor with your garmin device. Once your garmin device has successfully found your Tempe sensor you can go to the TruFlite Option menu and turn the "Tempe Sensor" option "on". In order to conserve battery, the Tempe sensor only transmits temperature readings approximately once per minute. Therefore, when you first turn it on, it could take up to a minute before TruFlite will see a new value from the sensor. If TruFlite sucessfully gets an external temperature value it will be displayed in green, otherwise TruFlite will continue to use the manually provided temperature value, which will be displayed in white. Hitting/tapping OK/Select will cause TruFlite to update all sensor values and the firing solution.

The TruFlite ballistic engine is very fast. No need to pre-calculate any values and should return a firing solution immediately. If you wish to discuss ballistic engine internals feel free to contact me.

Accuracy: TruFlite results have been compared to several defacto standard ballistic engines; such as Applied Ballistics and JBM and is within inches or 0.25moa out beyond 1500 yards for long range cartridges and under various environmental conditions.

  • over 4 years ago in reply to jrjackson

    Apologies about the delay. Here are all the settings from Garmin Express. Also verified on the actual watch itself under the app settings.

    BC = 0.48

    Drag Curve = G1

    Muzzle Velocity = 3130

    Zero Range = 200

    Sight Height = 1.75

    Elevation Click Units = moa

    Elevation Click Precision = 0.5

    Windage Units = clicks

    Windage Click Units = moa

    Windage Click Precision = 0.25

    Elevation Correction = 0

    Range = 400

    Temperature = 59

    Cross Wind = 0

    Use Temp Sensor = off

    Distance Units = yards

    Wind Speed Units = mph

    Temperature Units = F

    Altitude Units = feet

    Pressure Units = inHg

    Muzzle Velocity Units = fps

    Sight Height Units = inches

    ************************************

    In the app on the watch it shows this:

    TruFlite

    .480 G1, 3130 FPS

    727ft, 29.13"Hg, 59F

    Elev.(clks) | Wind.(clks)

    0u | 0

    Range(y)

    450

  • over 4 years ago in reply to Lutraphobia

    Hi Jeff!

    BTW, I love these types of apps. I was super excited to find it. THANK YOU for developing it!!!!

    OK, I removed 1.5 and installed 1.6. I used the default setup for click units (inches) for Elevation and Wind and it worked.  I suspect this is just user error. :)

    I set the units to clicks instead of inches and now I am getting what I am looking for.

    However, I don't want elevation correction. Default it's set to one and I can't set it to zero in the watch app.

    EDIT: I changed Elevation Correction to 0 in Garmin Express under the App Settings. That gave me zeros in the solution. I set it back to default "1" and now the solutions are working again.

    What exactly does Elevation Correction do? Why do I need it set as 1?

    Couple questions:

    Can I have multiple setups (different rifles and different ammo)?

    Currently I am using the Android "Shooter" app. It asks me to setup the rifle (with barrel twist). Note, I see this app also has elevation and windage correction (default set at 1). Then it asks to set up the ammo you are using. It asks for Bullet Diameter and Bullet Weight. Is that also important to the calcs?

    Again, thanks for this. This is a lot easier then using my phone in the field. Much appreciated!!

    -L

  • over 4 years ago in reply to Lutraphobia

    Ok.  Thanks for the data dump.  You hit it exactly, the problem was that "Elevation Correction" got set to zero.  It should be set to 1.0 for no correction.  I limit the range of "Elevation Correction" to between 0.90 and 1.10 when input from the watch, but i have no control over the Connect IQ App inputting something different.

    "Elevation Correction" is used to correct for scopes where their clicks are not exactly as advertised.  For example:  supposed to be 0.25 moa but in reality it is 0.24 moa.   That means your scope clicks are off by 4%.   So one would enter a correction factor of 1.04

    1.0 means the scope is exactly what it is supposed to be.    Most scopes are probably off only a few percentage so the value will most like be between 0.95 and 1.05.
    Here is a video from Brian Litz/Applied Ballistics showing how to find out if you need a correction.    Correction factor in something like Applied Ballistics and TruFlite should be the same.
  • over 4 years ago in reply to jrjackson

    Awesome. Learn something new every day. Thanks for sharing that knowledge Jeff. Much appreciated!

    Any other insight on my questions about twist rate / bullet weight, etc?

  • over 4 years ago in reply to jrjackson

    I have a Montana 700i, Trueflight isn't showing up in Connect IQ.  Am I looking in the wrong place ?

  • over 4 years ago in reply to 9284466

    Just popped up, thanks for making this available.  Love it

  • over 4 years ago in reply to Lutraphobia

    To calculate additional effects like spin drift and aerodynamic jump one needs to calculate some stability which requires bullet weight, caliber, length, twist rate and twist direction.   For vertical and horizontal coriolis effects one needs latitude and azimuth.   In order to keep TruFlite simple, as those are alot of additional inputs thru a watch interface, i left them out.  And these effects are usually pretty minor for ranges out to 1200 yards.     But alot of people ask for them, so i am trying to figure out how to add some of them without complicating the user interface too much.

  • over 4 years ago in reply to jrjackson

    Fantastic reply. Thanks for taking the time to do that as well as the great explanation. I look forward to future versions!

  • over 3 years ago

    Is it possible to adapt the function with the next update so that new profiles can be created for other weapons? I use the app in long range shooting and there I use different weapons. therefore it would be useful if you could create a profile for every weapon.

  • over 3 years ago in reply to 2137862

    Yes, great idea, strang after not being able to shoot for a while I took several rifles out. Different profile would be great. I personally would like to be able to input my own dope as I’m still having issues getting close on 6.5crdm.

    love this app, well done to the creator. I’m getting better with it as I get more accurate data.