"Flying the field"....Broad Experience Input from YOU!

[MarsLander]

As some know, Long time BABABAR. Lots of LPR, some mid, some high. L1 around 2000. Back at it with L2 this spring/LDRS (see Viper build link in signature).

I now have a 1500'x1500' (Red Box) field about 5 minutes from home. Tree line at the south end (right behind Green X), with another 600" directly south and 750' to the east, or so of open field behind the trees to the south/east (yellow box). I can fly from anywhere on the field, depending on the winds.



I'm re-learning to "fly the field."

We spent the day on Sunday learning the new field and re-learning how to "fly the field." Winds were about 5-10 out of the south east, launching on the south end of the field (green X). Upper level winds were much faster than surface winds (more on that later). First flight, flew to the south and recovered behind the tree line to the south (in the Yellow Box). Oh...yeah...point downwind to have a vertical launch. DUH! Check!

Probably another 10 launches or so were great, Point it downwind about 5 degrees, great vertical launches most recovery within 2-400', including a Cherokee-E on a C6-5. All good.

Last launch of the day, loaded up the Cherokee with an E-12. Send it!...or so I thought. Right...with a 15" parachute. See ya! Ended up at the red X, or there abouts! As my mother would say, "that's the price of an education!"

Again, this is about learning to fly the field. I have my own thoughts, which I will share here, would LOVE to hear your thoughts about flying the field!

1. The field is a hay field. It is not hard, but VERY soft, and the geographic area is generally wet (all the time). It would be easy to fly this field with streamers and will experiment with simple streamer recovery, or much reduced parachute sizes. We had one deployment that didn't eject the parachute and came in hot. The CA at the end of the tube protected it from damage.
2. Leverage Rocksim/OpenRocket to do simulations of descent rates and G. Harry Stine parachute CD rates (1.09), with wind forecasts to figure out parachute sizes to stay within the field. (p. 186 Handbook of Model Rocketry 7th edition from Top Flight). Also using a 1 piece launch rod and measure launch angles (entered into rocksim) to launch into the wind and predict landing locations.
3. Use Windy and GPS drift calculations (https://www.rocketryforum.com/threa...-predictor-and-visualizer-spreadsheet.165859/). Though for the Cherokee-E, there isn't much altitude discrimination (it goes from 330ft to 200ft in one step), and likely apogee was 1600'...it was a nice vertical flight!

For a L2 flight, I think approach 3 would be a good route. How much launch angle discretion are you allowed when setting up a 1515 rail? I understand that the field and the spectator location is a big input to launch location and angles...how much adjustability and discretion is allowed to the flier?

Thanks for your help and insights!

MarsLander.

 

[lr64]

Is this why some people go ridiculously large instead of ridiculously high for their certification?

Dual deploy?

 

[Voyager1]

As some know, Long time BABABAR. Lots of LPR, some mid, some high. L1 around 2000. Back at it with L2 this spring/LDRS (see Viper build link in signature).

I now have a 1500'x1500' (Red Box) field about 5 minutes from home. Tree line at the south end (right behind Green X), with another 600" directly south and 750' to the east, or so of open field behind the trees to the south/east (yellow box). I can fly from anywhere on the field, depending on the winds.

View attachment 634005

I'm re-learning to "fly the field."

We spent the day on Sunday learning the new field and re-learning how to "fly the field." Winds were about 5-10 out of the south east, launching on the south end of the field (green X). Upper level winds were much faster than surface winds (more on that later). First flight, flew to the south and recovered behind the tree line to the south (in the Yellow Box). Oh...yeah...point downwind to have a vertical launch. DUH! Check!

Probably another 10 launches or so were great, Point it downwind about 5 degrees, great vertical launches most recovery within 2-400', including a Cherokee-E on a C6-5. All good.

Last launch of the day, loaded up the Cherokee with an E-12. Send it!...or so I thought. Right...with a 15" parachute. See ya! Ended up at the red X, or there abouts! As my mother would say, "that's the price of an education!"

Again, this is about learning to fly the field. I have my own thoughts, which I will share here, would LOVE to hear your thoughts about flying the field!

1. The field is a hay field. It is not hard, but VERY soft, and the geographic area is generally wet (all the time). It would be easy to fly this field with streamers and will experiment with simple streamer recovery, or much reduced parachute sizes. We had one deployment that didn't eject the parachute and came in hot. The CA at the end of the tube protected it from damage.
2. Leverage Rocksim/OpenRocket to do simulations of descent rates and G. Harry Stine parachute CD rates (1.09), with wind forecasts to figure out parachute sizes to stay within the field. (p. 186 Handbook of Model Rocketry 7th edition from Top Flight). Also using a 1 piece launch rod and measure launch angles (entered into rocksim) to launch into the wind and predict landing locations.
3. Use Windy and GPS drift calculations (https://www.rocketryforum.com/threa...-predictor-and-visualizer-spreadsheet.165859/). Though for the Cherokee-E, there isn't much altitude discrimination (it goes from 330ft to 200ft in one step), and likely apogee was 1600'...it was a nice vertical flight!

For a L2 flight, I think approach 3 would be a good route. How much launch angle discretion are you allowed when setting up a 1515 rail? I understand that the field and the spectator location is a big input to launch location and angles...how much adjustability and discretion is allowed to the flier?

Thanks for your help and insights!

MarsLander.

You’ve identified wind and descent rate as important parameters for flying the field, but don’t forget motor impulse as an important factor in controlling altitude. Simulations are very useful, but should be used with accurate simulation model parameters.

At the beginning of the launch session on a small field, start with a low impulse launch to get an idea of the drift.

As for HPR launch rail/rod angles, the Tripoli requirement is for no more than 20 degrees off vertical, and only with the RSO’s approval. Never tilt towards the spectator and launch control areas.

 

[kjhambrick]

@MarsLander --

Now that I am flying in Texas, I too am trying to learn to fly the field ( and the local weather conditions ).

Until recently, I've been depending on @JimJarvis50's landing scatter plots for the AARG Hutto and Apache Pass sites

Jim's landing scatter plots for AARG launches the past year have been uncannily accurate for my flights.

At the same time, I've been studying 3D plotting in Open Rocket so I could try to match Jim's predictions.

I didn't know about @dvdsnyd's TRF > GPS Drift, Rocket Landing Predictor and visualizer Spreadsheet or his new GPS DriftCast (GPS Drift 2.0) ( that you've collaborated on ) until fairly recently ...

What a wonderful tool !

The method I was using was to set up a sim as accurately as possible using pressure, temperature and wind velocities in Open Rocket.

Then run my sims and look at the Ground Track Plot without any rotation then when I know how far the rocket would weathercock and drift, align the track with the wind direction on the ground and look at it in google maps.

For example, this is my best guess sim setup for an upcoming flight on Saturday at the Texas Shootout in Seymour TX.

Wind speed maybe 15 mph or so and direction is the default 180 deg:

And this is the OR plot:

So the rocket should drift a total of about 3,000 ft from apogee with a 15 mph wind ( 600+ ft weathercock and 2300+ ft drift under the chutes ).

You mentioned angling the launch rail in a PM and you got me wondering ... what if ?

This is the TP on the same I211W with the launch rail is angled 12 degrees upwind:


It looks like it would land within 100 ft or so from the pad if I launch at 12 degrees upwind.

One problem with large initial angles is that the drogue will be deployed at about 120 ft/sec and I am not sure I could avoid a zipper, even with TP's glassed cardboard airframe.

I am with @Voyager1 -- maybe the only way to really fly the field is to adjust your impulse and the final apogee altitude so you can stay in bounds ?

-- kjh

TL;DR ...

I was lucky back in the 1990's when I first BAR'd and certified L1 and L2 because I was in SoCal and there were a number of vast, flat launch sites out there with very few hazards to contend with.

Never gave it a thought at my TRASD home field ( Ocotillo ) or on the dry lake beds at a ROC launch or Tripoli Vegas Launch ... prep it and send it and track it and chase it ...

Actually, I did try to fly in the early morning when it was cooler and at Ocotillo before the hot desert air started rising and slurping the cold sea air from San Diego, across the coastal range and the winds got too high and the site got too hot ( I noticed the same general weather pattern on the dry lake beds too ).

Now I am in TX with only seven flites under my belt since I re-BAR'd in April 2023.

I am still learning how to fly the site and the weather ...

More times than not, I've landed in some sort of hazard:

1. Jun 23 - Apache Pass - SJ - H128W - 800 ft Level 1 flite - fin can landed in a swampy bog
2. Nov 23 - Hutto - NM - J350W - 4000 ft Level 2 flite - landed on the ground
3. Dec 23 - Hutto - SJ - I225FJ - 4000 ft - landed on a power line
4. Feb 24 - Hutto - SJ - I357T - 4000 ft - landed on the ground
5. Mar 24 - Hutto - TP - H180W - 4000 ft - landed 20 feet up in an elm tree
6. Apr 24 - Apache Pass - TP - I161W - 6000 ft - landed on the ground in a corn field (*)
7. May 24 - Hearne - TP - H180W - 4000 ft - landed 10-feet up in a mesquite tree

Legend: SJ - Spock's Johnson ( 2.26 inch LOC Vulcanite ),
NM - Nocturnal Missions ( 2.95 inch glass Vulcanite upscale ),
TP - T'Pring's P'Toy ( 1.9 inch Vulcanite downscale )

(*) - I might have lost TP in the knee-high corn field if not for the tracker -- it was invisible just 10 ft away !

So ... Only three smiley faces -- a .429 batting average -- but four times out of seven I landed in a hazard ( pond, power line, tree, tree ).

 

[SolarYellow]

You can fit dual deployment in BT-5 with a commercially available altimeter. You can do non-pyro DD in slightly larger tubes with much less expensive altimeters, which means your average LPR rocket can be a DD rocket and you don't have to spend the money or have the tube size for a JLCR.

That can be the answer for a lot of places. It also mostly protects you from thermals, which can throw wind speed calculations out the window.

 

[kjhambrick]

You can fit dual deployment in BT-5 with a commercially available altimeter.

@SolarYellow --

Which Altimeter(s) did you have in mind that fit a BT-5 ?

I've got to get a pair of those 'for my granddaughters'

Thanks !

-- kjh

 

[SolarYellow]

You better really love them, it ain't cheap.

https://northcoastrocketry.com/products/adrel-deploymax-altimeter-single-event-deployment

To run dual deploy, you either use two of them, or do motor eject and then eject the main with the DeployMax. I haven't figured out yet whether it can run a hot wire setup.

I'd probably go with a Quark in BT-20 or BT-50 instead.

 

[dvdsnyd]

Now that I am flying in Texas, I too am trying to learn to fly the field ( and the local weather conditions ).

Until recently, I've been depending on @JimJarvis50's landing scatter plots for the AARG Hutto and Apache Pass sites

Jim's landing scatter plots for AARG launches the past year have been uncannily accurate for my flights.

@kjhambrick
Could you expound a bit on Jim's landing scatter plots?

 

[kjhambrick]

@kjhambrick
Could you expound a bit on Jim's landing scatter plots?

@dvdsnyd --

I'll have to let @JimJarvis50 explain how he does that magic that he does

-- kjh

 

[Voyager1]

To get a better prediction on potential landing spots, you could use the OpenRocket multilevel winds add on. You can get the multilevel wind data from Windy or aviation wind forecasts.

https://github.com/rocketsam2016/MultiLevelWind/releases/tag/latest

Check out the previous thread about this.

https://www.rocketryforum.com/threa...peed-direction-at-different-altitudes.140619/

You could also try the Cambridge Rocketry simulator that provides 3D flight profiles and scatter plots using Monte Carlo distribution.

https://cambridgerocket.sourceforge.net/download.html

Additionally, you could use RocketPy which provides 3D flight profiles and scatter plots on Google Earth. This application uses forecast wind models to provide multi level wind data.

https://docs.rocketpy.org/en/latest/

Of course, all of the above is possibly a little over the top for a small field where surface winds are enough to get your predictions. However, for large recovery areas and high altitude flights, they might be useful.

 

[bad_idea]

More times than not, I've landed in some sort of hazard:

1. Jun 23 - Apache Pass - SJ - H128W - 800 ft Level 1 flite - fin can landed in a swampy bog

My Level 2 flight ended up in the head-high corn at that launch. Eggfinder Mini took me right to it. Actually was flying two of them, one known-good and one I was testing, and they both took me to the rocket.

You better really love them, it ain't cheap.

https://northcoastrocketry.com/products/adrel-deploymax-altimeter-single-event-deployment

To run dual deploy, you either use two of them, or do motor eject and then eject the main with the DeployMax. I haven't figured out yet whether it can run a hot wire setup.

I'd probably go with a Quark in BT-20 or BT-50 instead.

Huh, I never noticed the altitude setting for the MaxDeploy. Not sure I could come up with a case to fly two of them in BT-5 with existing commercial motors, but it's a cool capability.