Visual Drift Distance Calculator

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

peter_stanley

Well-Known Member
Joined
Apr 11, 2009
Messages
222
Reaction score
1
I just finished a new free rocketry tool. It's available in the Google Play store now, and will be on the Apple Appstore once it's approved.
https://play.google.com/store/apps/details?id=com.gmail.pstanley002.drift_distance_calc&hl=en

This calculates drift distance, based on given altitude, descent rate and wind speed. Then shows a satellite image of the users current or searched location at the center of a shaded circle overlay. The radius of the circle (from the center point out) represents the translated drift distance.

This can help show any potential hazards or obstacles in the recovery area.

Two use cases are:

1. Determine if the launch site is large enough for the given wind conditions, estimated altitude and descent rate. So if it looks like the rocket might drift into trees, water, etc... the user could try to increase the descent rate by using a smaller chute or streamer, or use a smaller rocket motor. Either change would result in a smaller drift distance, and stay within a safe recovery range.

2. Determine a starting search area for rockets that have drifted out of view.

* The app requires an Internet connection and gps to acquire location. If an Internet connection is available, but the location still can't be determined, the last acquired location will be used. If that isn't available then the default is used, which is the Super Sod field in Orangeburg, SC. You can type an address or latitude/longitude coordinates in the map search box to display a different location.

* Use your rocketry calculating tool of choice to estimate altitude and descent rate.

* Supports multiple combinations of metric and imperial unit settings.

* As always, use sound judgement and don't base decisions entirely on this app.

icon512rounded.png

IMG_0848_47.jpg

IMG_0849_47.jpg
 
I'll be downloading this once my phone charges up :)

Nate
 
Just downloaded and installed it. I set up a 20k scenario @ 55f/s decent with a 10MPH wind and it came back with just over a mile however the map did not automatically scale back to see the circle overlay. Not a big deal but it would be great if it did auto zoom out or in depending on the search radius.

Thank you Peter.
 
Just downloaded and installed it. I set up a 20k scenario @ 55f/s decent with a 10MPH wind and it came back with just over a mile however the map did not automatically scale back to see the circle overlay. Not a big deal but it would be great if it did auto zoom out or in depending on the search radius.

Thank you Peter.
I'll take a look at that in the next update. Good stuff to hear. Thanks for the suggestion.

Peter
 
Man, there sure is a lot of talent on this site. Thank you for this. I fly on the rock hard playa in So Cal but this looks very interesting to use to avoid the roads nearby.
 
Next to a safe launch rod departure, this is the most critical objective on launch day - successful recovery of the rocket. I have done all this manually in the past - Measure wind, do the sim, and then plot and measure on Google Earth. It is very cool that you combined this in a handy app. Thanks.

Suggestions for v2.0:

Two levels of altitude and descent rate to simulate dual deployment

Multiple levels of winds aloft
 
Next to a safe launch rod departure, this is the most critical objective on launch day - successful recovery of the rocket. I have done all this manually in the past - Measure wind, do the sim, and then plot and measure on Google Earth. It is very cool that you combined this in a handy app. Thanks.

Suggestions for v2.0:

Two levels of altitude and descent rate to simulate dual deployment

Multiple levels of winds aloft

Those are excellent suggestions. Thanks! Please post after you've had a chance to use it in the field and let me know how it worked for you.
 
I just downloaded the Iphone version.
It seems to me that the wind direction would be important data. It would turn the circle into an oval which is probably a lot harder to calculate and display.
Still usefull information.
 
Does it assume that the rocket goes straight up, or does it account for the arc through apogee? Weathercocking?

Have you thought about adding a dual seployment calculator? IOW, if apogee is at 3000 feet, and main is at 300 feet, what is drift prior to main and after main?
 
Does it assume that the rocket goes straight up, or does it account for the arc through apogee? Weathercocking?

Have you thought about adding a dual seployment calculator? IOW, if apogee is at 3000 feet, and main is at 300 feet, what is drift prior to main and after main?

Yes, the assumption is straight up, but you can touch the circle and drag to re-position if needed. Some others have suggested dual-deployment calc as well, and I definitely see the use for it. I'll try to incorporate into the next update. Also thinking through something, from another suggestion, about letting the user select wind direction and show that on the map overlay.
 
Problems:

Winds aloft for very high flyers can vary direction and be very dynamic. In that reqard, not a very useful app in that situation. Folks in that flight regime are likely using a tracker of some kind anyways. For a lower flying rocket, could be helpful but one has be be able to input accurate data. Again windspeed at ground level may be different at altitude. Also descent rate might be off if one is using a sim calculated value. A better alternative would be using altimeter data from a prior flight to calculate a more accurate descent speed. I base the above on realtime tracking of GPS rockets on a laptop map. It is amazing how some of the rockets "fly around" after drogue deployment at altitude and how they end up nowhere near anyone could predict using ground windspeed alone.

No internet connection? Probably not very helpful unless the mapset could be cached and saved of at least the launchsite and surrounding area. A possible alternative would be to use an Open Source mapset that could be stored on the device and used without
internet access.

One very useful purpose would be as the developer states, is determine if a launchsite is "adequate" for a given windspeed. An estimate could be very helpful in determining if that 15mph expected winds are too much for a given geography. Kurt
 
Problems:

Winds aloft for very high flyers can vary direction and be very dynamic. In that reqard, not a very useful app in that situation. Folks in that flight regime are likely using a tracker of some kind anyways. For a lower flying rocket, could be helpful but one has be be able to input accurate data. Again windspeed at ground level may be different at altitude. Also descent rate might be off if one is using a sim calculated value. A better alternative would be using altimeter data from a prior flight to calculate a more accurate descent speed. I base the above on realtime tracking of GPS rockets on a laptop map. It is amazing how some of the rockets "fly around" after drogue deployment at altitude and how they end up nowhere near anyone could predict using ground windspeed alone.

No internet connection? Probably not very helpful unless the mapset could be cached and saved of at least the launchsite and surrounding area. A possible alternative would be to use an Open Source mapset that could be stored on the device and used without
internet access.

One very useful purpose would be as the developer states, is determine if a launchsite is "adequate" for a given windspeed. An estimate could be very helpful in determining if that 15mph expected winds are too much for a given geography. Kurt

Right. I don't think the intent of the app is another flight simulator. User inputs altitude, wind, descent rate from any source he chooses. The app then gives a visual of the drift, as the name implies!
 
I base the above on realtime tracking of GPS rockets on a laptop map. It is amazing how some of the rockets "fly around" after drogue deployment at altitude and how they end up nowhere near anyone could predict using ground windspeed alone.

Right. I don't think the intent of the app is another flight simulator. User inputs altitude, wind, descent rate from any source he chooses. The app then gives a visual of the drift, as the name implies!

I'm not sure you picked up on what ksaves2 was trying to say. By all means, build the app and learn as much as you can doing it, but don't expect it to be used a lot because of the reasons ksaves2 states. High altitude flights (+3000 ft) have winds aloft that cannot be determined by ground winds making any inputs inaccurate. This makes the app useful for low altitude only. As ksaves2 said, rockets "fly around" after drogue deployment. When a fin can pulls the payload down and is angled toward the ground about 15 to 20 degrees, the fins work like wings giving it a horizontal speed and the fin can will pull the payload in whichever direction it is pointing in. I've seen a rocket move 1000 ft south after a 2,500 ft flight when the wind was out of the west.

I don't want to discourage you from building the app, the more tools we have the better. I just want to be realistic about the usefulness of it in some real world situations.
 
I just finished a new free rocketry tool. It's available in the Google Play store now, and will be on the Apple Appstore once it's approved.
https://play.google.com/store/apps/details?id=com.gmail.pstanley002.drift_distance_calc&hl=en

This calculates drift distance, based on given altitude, descent rate and wind speed. Then shows a satellite image of the users current or searched location at the center of a shaded circle overlay. The radius of the circle (from the center point out) represents the translated drift distance.

This can help show any potential hazards or obstacles in the recovery area.

Hi

Two use cases are:

1. Determine if the launch site is large enough for the given wind conditions, estimated altitude and descent rate. So if it looks like the rocket might drift into trees, water, etc... the user could try to increase the descent rate by using a smaller chute or streamer, or use a smaller rocket motor. Either change would result in a smaller drift distance, and stay within a safe recovery range.

2. Determine a starting search area for rockets that have drifted out of view.

* The app requires an Internet connection and gps to acquire location. If an Internet connection is available, but the location still can't be determined, the last acquired location will be used. If that isn't available then the default is used, which is the Super Sod field in Orangeburg, SC. You can type an address or latitude/longitude coordinates in the map search box to display a different location.

* Use your rocketry calculating tool of choice to estimate altitude and descent rate.

* Supports multiple combinations of metric and imperial unit settings.

* As always, use sound judgement and don't base decisions entirely on this app.

View attachment 258307

View attachment 258309

View attachment 258310
 
I just finished a new free rocketry tool. It's available in the Google Play store now, and will be on the Apple Appstore once it's approved.
https://play.google.com/store/apps/details?id=com.gmail.pstanley002.drift_distance_calc&hl=en

This calculates drift distance, based on given altitude, descent rate and wind speed. Then shows a satellite image of the users current or searched location at the center of a shaded circle overlay. The radius of the circle (from the center point out) represents the translated drift distance.

This can help show any potential hazards or obstacles in the recovery area.

Peter I'm trying to use the links in this post but they just take me to ads? Can you please provide a like for you app? or can I get it from
Google play whit is the name of your app?
thanks Brian

Two use cases are:

1. Determine if the launch site is large enough for the given wind conditions, estimated altitude and descent rate. So if it looks like the rocket might drift into trees, water, etc... the user could try to increase the descent rate by using a smaller chute or streamer, or use a smaller rocket motor. Either change would result in a smaller drift distance, and stay within a safe recovery range.

2. Determine a starting search area for rockets that have drifted out of view.

* The app requires an Internet connection and gps to acquire location. If an Internet connection is available, but the location still can't be determined, the last acquired location will be used. If that isn't available then the default is used, which is the Super Sod field in Orangeburg, SC. You can type an address or latitude/longitude coordinates in the map search box to display a different location.

* Use your rocketry calculating tool of choice to estimate altitude and descent rate.

* Supports multiple combinations of metric and imperial unit settings.

* As always, use sound judgement and don't base decisions entirely on this app.

View attachment 258307

View attachment 258309

View attachment 258310
 
Peter,
I think your App development will be very helpful to fellow flyers. The point raised by ksaves2 and handeman are very valid. If one looks at www.ventusky.com, you'll find a map extrapolation of current wind speeds at intervals of 50 meters above ground level. For example see below a partial copy of the site for Rembert S.C. where the ICBM club launches. The point displayed was noon eastern (17 minutes ago) and the wind speed calculated at an altitude of 1500 meters was 29 mph (look at lower right above "Godgold Subdivision" where it lists 29 mph). If the algorithms used for altitude based wind speeds are relatively accurate, with the use of your App, I believe it will be a significant tool for HPR enthusiasts. It would be interesting to determine the accuracy of the Ventusky algorithm (or others) and its use with your App to acquire more accurate results.

Fred, L2
ICBM, Camden (Rembert), S.C.
KG4YGP
upload_2020-3-21_12-20-50.png
 
OK very old post..... anyhow my comments

Hey Peter very brilliant!! Adding upper level winds and rocket ballistic arc would really be of benefit. The arc will give you a landing point if all does not go well but also give a probable apogee location. Of course assumes a good flight. I built a spread sheet version many years ago and still use it today, being in Canada I use Nav Canada upper winds aloft data for that day as a beginning for the drift. but interestingly enough all the upper winds data comes from computer modeling done south of us in your country.

Also adjusting for Barometric and humidity helps define air density for a better decent rate calculation. Adding a error figure to the whole works helps define an area to look in. Most upper wind data is modelled and sometimes accurate. Also if going this route having a way to save old wind data would be wise, once the data is updated from your source it disappears and I have not found a way to recover old data. Usually needed to find that one last high flyer that went missing days before.

I'd be happy to share what I have done if that helps. Now if I could only figure out how to code for androids....

Enjoy
David

wind drift calculator snapshot.JPG
 
Back
Top