Hello All,

The following method is new to model rocket tracking, but it is not new in and of itself. I am also a pibal (pilot balloon) and weather balloon--and weather in general--"geek" (I collect pibals, pibal lighting units [for night observations], sounding balloons, radiosondes, and their accessories & manuals), and there is a pibal tracking method--called the "tail method"--that should also work for tracking model rockets.

(I'm a member of the local Pioneer Air Museum [see: https://www.pioneerair.museum/ ], and it turns out that a fellow member, Dave Williams, also collects weather balloon hardware; we met years ago when I worked at our airport [he worked at the RAOB--RAdiosonde OBservation--weather balloon station at the airport, and in September of 2008 he gave me a tour of the facility and let me assist with preparing, launching, and receiving data from a radiosonde weather balloon at their station [^here^ https://www.youtube.com/watch?v=mErNeiw8-38 it is--they now use a Vaisala-made weather balloon "vending machine," as they call it, which you can see there].) Now:

Here is the "tail method" (see: https://home.csulb.edu/~mbrenner/glossary.htm )--the opening page of that site, "Martin Brenner's Pilot Balloon Resources," is *here*: https://home.csulb.edu/~mbrenner/ . It contains a wealth of pilot balloon and theodolite information (it's also linked-to at the bottom of this Ceiling Balloons article: https://en.wikipedia.org/wiki/Ceiling_balloon [the 10-gram ceiling balloon--they're mostly made in red, black, and green, and also in natural <un-colored> gum, yellow, and orange, in order to be visible against different sky backgrounds--is a specific type of pibal]), and:

Using the "tail method" (named for the streamer-type tail of known length, tied to a pibal before it's launched), a rocket's streamer length, or parachute canopy width, or the vertical "height" from the parachute canopy peak to the shroud lines' tie point (measured, and thus of known size) would have its angular size repeatedly measured and recorded (even verbally, on an audio recorder) using the tracking theodolite's eyepiece graticule (also called a reticle). Incidentally, pibal-tracking theodolites make great one-, two-, or three-station (using elevation only for the three-station set-up, as shown in the Stines' "Handbook of Model Rocketry" [including the earlier editions that G. Harry wrote by himself]). This--along with the theodolite's azimuth and elevation angles recorded at the same times--would, using trigonometry, establish the rocket's exact position.

I hope this information will be useful.

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NAR #54895 SR

Almost sounds like a form of stadia distance gathering, but kinda in reverse.

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Bernard J. Herman Ohio RLS

Starport Sagitta Rockets
email bherman@sagittarockets.com

NAR # 97971 SR

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We're looking for a few good Catos, please tell us about any you may have had. Survey of Anecdotal Malfunctioning Engines or S.A.M.E.

Thank you--I had to look up that term, and learned something new! (Here [see: https://www.newenglandlaser.com/gfs...pdfs/stadia.pdf and *here* https://www.google.com/search?q=sta...sclient=gws-wiz ], for others who may also be interested, are links to information on these techniques.) Also:

Yes, it is like those; the only difference is that length units and numbers aren't written or printed on the pibal tails (or on rockets' streamers), although that could easily be done if desired.

Pibal visual observations, using one or two theodolites (and its or their recorded azimuth and elevation angles, versus time) were, before practical and cheap radiosondes were developed, the weather balloon operations that aerologists and meteorologists used--along with their other, ground-based instruments--to develop weather forecasts. Pibals are still used for fire weather observations; gathering detailed wind flow fields data helps fire officials decide when (or if) to order evacuations of certain areas, where to safely drop smoke jumpers to fight the fires, etc. For night pibal observations, a low-mass lighting device (either a ~4-1/2" diameter x ~8" tall cylindrical tissue paper candle lantern [*not* used in tinder-dry conditions, of course! :-) ], or a flashlight bulb unit powered by a water-activated battery; below I have attached pictures of these lighting devices) is attached to the pilot balloon. As well:

The National Wildfire Coordinating Group (NWCG, see: https://www.nwcg.gov/ ) uses pibals--pilot balloons--and theodolite observations of them (see: https://www.nwcg.gov/term/glossary/...0wind%20profile. ) Plus:

Theodolites, while available, tend to be expensive. Much simpler and cheaper elevation angle-only sighters (with or without low-power telescopes; 25x magnification is common for theodolite telescopes, and inexpensive yet high-quality monocular scopes [see: https://www.ebay.com/sch/i.html?_fr...pe&_sacat=28179 ] could be used as elevation angle-only sighters) could be used instead of theodolites for tracking wildfire-monitoring pibals, utilizing the three elevation angle-only sighters method that G. Harry Stine covered, with diagrams, in his "Handbook of Model Rocketry." The 3-elevation sighter method (in which two stations are set up at the ends of a measured baseline, with the third station set up at the middle point of the line) was tested--simultaneously--along with a "standard" 2-theodolite tracking network (whose two theodolites were at the ends of the baseline), and the two different tracking systems yielded equally-accurate results, AND:

Both the three-station and two-station (2-theodolite) tracking methods--and the "quick and dirty" (but less accurate, of course) single-station, elevation-only tracking method and the "drop streamer" method--are in G. Harry Stine's "Handbook of Model Rocketry"--*here* (see: https://ia601905.us.archive.org/30/...207th%20edn.pdf ) is a PDF scan of the latest, Seventh Edition of the book. As well:

For pibal-tracking fire weather work, one wants relatively low-altitude pilot balloons--at least some of them--to "hang around" in the area, where they are tracked by one, two, or three theodolites, or elevation angle-only sighters. The Poker Flat Research Range, Alaska's suborbital sounding rocket range (located thirty miles north of Fairbanks; some years ago I was the volunteer range historian: https://www.pfrr.alaska.edu/content/welcome-poker-flat ), launches both radiosonde sounding balloons and pibals (pilot balloons) before sounding rocket launches, for two different but related reasons:

The radiosondes return upper-air data, including on winds. The pibals are ballasted (and--before night launches--they carry chemical light sticks, to facilitate visual tracking; the light sticks also form part of the ballast, as they're heavier than pibal lighting units) so that they float around at low altitude in the launch pads area, and they carry DIY (Do-It Yourself) aluminum foil "bow ties," about 18" - 24" wide, which enable the rocket-tracking radar to also track the pibals. The launch pads area is near a ridge, and nearly all of the sounding rockets are un-guided and fin-stabilized, so knowing the wind flow fields at low altitudes above the launch pads--when the rockets are moving slowest, just after liftoff--is of supreme importance, to ensure minimal impact dispersion of the sounding rockets' spent stages, payload fairings, payloads' ejected sub-payloads, and the main payloads' parachute landing points downrange. (Below are the pibal lighting unit photographs.)

Attached Thumbnails

     

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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
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All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

Not new. Theodolites have been in use since the earliest days of model rocketry - but - we all already know that. Right?

The rules for contests (the only type of launch where anyone commonly used theodolites to track rockets) have changed to make altimeters the norm. I suspect that the sun has set on theodolite tracking in model rocketry, not counting those protractor thingees that Estes sells.

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The simple machines (the lever, wheel and axle, pulley, inclined plane, wedge, and screw, see: https://en.wikipedia.org/wiki/Simple_machine ) are centuries to millennia old, but they are used--by themselves, or in all sorts of other devices--and no one (either their manufacturers or their users)--complains that "They're old." Likewise, the age of the theodolite (or theodolites, depending on the specific variant of the model rocket [or pibal] tracking set-up used) tracking method is irrelevant, and:

Fire weather pibal trackers, including in my part of the country, use theodolites to track the pilot balloons, to map the low-altitude wind flow fields above and around the fires in detail; this facilitates fighting the fires (with smoke jumpers and water/flame retardant-dumping helicopters, seaplanes [which operate from--and scoop up water from--lakes & rivers], and large, land-based, fixed-wing aircraft), and getting the fires under control more quickly. The pibal theodolites that they use--in Alaska and in the other, often forest fire-afflicted states--are shown and described *here* (see: https://home.csulb.edu/~mbrenner/balloon.htm ). Many of these theodolites, which are still in production, date back to the 1940s! But those who use them to track pibals don't complain that "They're old," either; to the contrary, they find these well-designed optical instruments to be easy to set up, and to use!

(For most of the summer, we've had dense smoke from multiple forest fires about 80 miles from Fairbanks filling up our "bowl" valley; the dense particulates and the filmy, suspended tree bark ash--to which many people are strongly allergic!--made it unsafe to spend *any* time outdoors. The health warnings, issued by public health officials, said that people of ALL ages were at serious risk from the smoke, and that avoiding all exertion was strongly advised. This has happened much more often than not, during our summers here, but it has one "silver lining"--for the next three or four summers after a "smoky summer," the mosquitos, which treat people here like drink vending machines, are almost absent.) Also:

The altimeters aren't ideal, because certain types of model rockets can't readily carry them without modification, such as punching an atmospheric pressure equalization hole in the payload section tube--if there is one--or perhaps somewhere in the body tube, and some models--such as small boost-gliders and rocket gliders, featherweight and tumble recovery rockets, scale models, etc.--can't carry them at all. Also, the hole's position (with respect to the altimeter), size, shape, and aerodynamic smoothness will affect an altimeter's operation (a messily-punched hole will have rough edges that cause eddies in the incoming or outgoing airflow, which would affect the altimeter's perceived ambient air pressure [and/or delay its ability to register the correct altitude; in very short flights, it could prevent correct altitudes from being registered]). As well:

Altimeters teach relatively little; the student or youth group member pushes a button or two, then sees a number on the altimeter's LED or LCD display after the flight. The altimeter instructions can explain how they work, but it's like looking at an already-worked-out graph of a function. This isn't entirely without educational value, but its effectiveness (and the extent of what it can teach) pales beside the hands-on altitude tracking using theodolite or sighter devices, especially ones built and used by the kids, with guidance from an adult instructor. Doing it that way teaches tool-using skills, geometry, trigonometry, and data reduction. For contest purposes in such activities, altimeters are worthwhile as back-up altitude determination devices (with optical trackers being the primary system), and the models can be selected beforehand to be ones that are compatible with the altimeters.I wasn't writing primarily about using theodolites (except as a reference, mostly), but about an old method used for pibal (pilot balloon) tracking, which involved measuring the apparent, angular sizes of a streamer-like attached tail of known length (versus time), as the pibals rose. The low-power--usually 25x, or thereabouts--telescope on a theodolite *can* be used to make such pibal tail-length (or model rocket streamer length, parachute canopy angular diameter, etc.) angular size observations, but it need not be; an ordinary, inexpensive (often $25 or less) monocular scope, mounted on a simple elevation-only sighting stick, can be used instead, but:

The three-station, elevation-only sighters (or Monocular scopes) tracking system, set up at the ends and the midpoint of a measured baseline, interests me most, for several reasons:

The elevation-only sighters (the ones that Quest Aerospace make are cardboard! [but they work--I've used them; Estes' sighter--which was originally Cox's--is molded polystyrene]), to which monocular scopes could easily be affixed, are very inexpensive, and DIY ones are very easy to make out of wood or metal. I have sent information about these sighters (and on the three-station, elevation-only sighters [or monocular scopes] tracking system, including the section explaining the set-up in the online PDF scan of the "Handbook of Model Rocketry") to several National Weather Service meteorological observers, including ones who have much experience in radiosonde weather balloon and pilot balloon preparation, launching, and tracking. They like the tracking system, which would work very well--at very low cost--for tracking pibals to gather fire weather data. The pibal theodolites are rather expensive, but three DIY elevation-only sighters (for the three-station tracking set-up), even with monocular scopes affixed to them, would cost only a small fraction of the price of a single pibal theodolite, yet the three-station, elevation-only sighter/monocular set-up is as accurate as the two-theodolite tracking set-up.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

Quote:

"The altimeters aren't ideal, because certain types of model rockets can't readily carry them without modification, such as punching an atmospheric pressure equalization hole in the payload section tube--if there is one--or perhaps somewhere in the body tube, and some models--such as small boost-gliders and rocket gliders, featherweight and tumble recovery rockets, scale models, etc.--can't carry them at all. Also, the hole's position (with respect to the altimeter), size, shape, and aerodynamic smoothness will affect an altimeter's operation (a messily-punched hole will have rough edges that cause eddies in the incoming or outgoing airflow, which would affect the altimeter's perceived ambient air pressure [and/or delay its ability to register the correct altitude; in very short flights, it could prevent correct altitudes from being registered]). As well:

Altimeters teach relatively little; the student or youth group member pushes a button or two, then sees a number on the altimeter's LED or LCD display after the flight. The altimeter instructions can explain how they work, but it's like looking at an already-worked-out graph of a function. This isn't entirely without educational value, but its effectiveness (and the extent of what it can teach) pales beside the hands-on altitude tracking using theodolite or sighter devices, especially ones built and used by the kids, with guidance from an adult instructor. Doing it that way teaches tool-using skills, geometry, trigonometry, and data reduction. For contest purposes in such activities, altimeters are worthwhile as back-up altitude determination devices (with optical trackers being the primary system), and the models can be selected beforehand to be ones that are compatible with the altimeters."

Your opinion - altimeters are fantastic for showing how pressure, temperature, etc. are related, not to mention the U.S. Standard Atmosphere and so on. Do they teach trig? No. But a good teacher/mentor can use them to teach a bunch of stuff. Plus you are ignoring the value in teaching someone to design/construct an altimeter, which is far more appealing to students these days. Constructing an actual instrument is cool. My club has a 12 year old with an altimeter project and it is amazing at how much he is learning.

In hobby rocketry, the age of the altimeter is here, for better or worse. The numerous "track loss" along with the pain of setting up tracking stations and manning them with people with decent eyes more than mitigate the deficiencies of altimeter use. Using the old style way of tracking is very frustrating for students - I know it was for my long ago mentees when they tried to measure the altitude achieved by their rocket. Even with tracking smoke to mark ejection, they couldn't get a track to close.

Have you ever worked with students using old school tracking, Blackshire?

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Actually, before I became entangled in being back to my land surveying job, I was working on a new concept tracking scope over at the Starport Sagitta. tracking theodolite

It used an inclinometer and a holographic site which would have made it a bit more user friendly (read better suited for youngsters). I Never did finish assembling the unit or checking it for accuracy and had not found a suitable horizontal circle to measure azimuths.

As was mentioned in the thread and by Blackshire above, there are issues with the use of a barometer for altitude measurement. Not least of which is the added weight of the unit itself.

One last thing, the "theodolites" of today (actually called total stations) are actually robotic and able to track targets. I have not been in the field with one in a long time and don't know there full potential, but they can also use reflectorless EDM's (Electronic Distance Measurement) to get distances. Given some initial backsites and distances, they will automatically output a height ob their screen. you could also have the information stored automatically in a data collector to be dumped into a computer program. That data can then be imported into a file which is then joined with Google Earth to show in 3D where the points were.

IOW, The good ole Jacob's Staff has evolved from the days of our forefathers. To think that just because a "theodolite" was used back in the day is to think that altitude reading barometers should just be some numbers on a clinky old dial.

Attached Thumbnails

 

__________________
Bernard J. Herman Ohio RLS

Starport Sagitta Rockets
email bherman@sagittarockets.com

NAR # 97971 SR

What's your idea on the best way to change Washington D.C.?
Let us know at the Cantina
Sagitta Cantina

We're looking for a few good Catos, please tell us about any you may have had. Survey of Anecdotal Malfunctioning Engines or S.A.M.E.

Since you're into high altitude balloons, you may know about the amateur radio (ham) efforts using high pressure balloons which are mylar balloons, often just 3 foot diameter typical disc shaped party balloons with no decorations, that don't expand beyond full inflation and therefore maintain a fairly consistent altitude.

Also, unlike latex balloons, they don't degrade rapidly due to solar UV. These amateur balloons with tiny sensors for altitude, temperature, and GPS position and a transmitter, all powered with a solar cell charged lipo battery have been tracked circling the Earth multiple times.

An amateur balloon tracker web page:

https://tracker.habhub.org

Shows a balloon and its instrumentation:

Asian Trek for B-47 Party Balloon

https://amsat-uk.org/2014/05/05/asi...-party-balloon/

Just discusses them, no photos:

Balloons Carrying Amateur Radio Payloads Still Circling Earth

http://arrl.org/news/balloons-carry...-circling-earth

Three simple plastic foil-envelope balloons carrying Amateur Radio payloads and launched from the UK by Leo Bodnar, M0XER, remain aloft and continue to circle the Earth. The oldest, identified as B63, was released on July 8 and became the second of Bodnar’s balloons to circumnavigate the globe. The first to do so, B64, went up on July 12 and had completed one lap around the Northern Hemisphere by July 31. Air currents have carried the balloon within 9 km of the North Pole and within 10 km of its launch site. The last balloon to make it around the Earth was B66, which Bodnar released on July 15.

Each balloon carries a tiny 10 mW solar-powered transmitter that can alternate between APRS and Contestia 64/1000 digital mode on 434.500 MHz (USB). The Amateur Radio payload weighs just 11 grams.

As of August 25 at 15:30: The B64 balloon (M0XER-4 on APRS) was north of Moscow, Russia, at an elevation of more than 40,200 feet; the B63 balloon (M0XER-3 on APRS) was located nearly 42,000 feet above South Korea, and the B66 balloon (M0XER-6 on APRS) appeared to be over the Celtic Sea and approaching the tip of southern England.

Bare tracker PCB:

HAB2 High Altitude Balloon Tracker RFM9x - This is a board intended to be used as a low component count high altitude balloon tracker using LoRa.

https://www.tindie.com/products/stu...-tracker-rfm9x/

Tracking and recovering weather balloon radiosondes:

How To Track Weather Balloons Using SDR

https://www.youtube.com/watch?v=HRYW_LmUPNc

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Hmmm, I don't think it would bode well for a turbine that may ingest one of these.

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The payload weighs 11 grams... and the FAA and other aviation authorities disagree that it's a hazard... and the thousands of weather balloons launched every year with much heavier payloads have caused no issues... and the sky is a VAST space where, as can be seen in the huge FAA database on aircraft incidents, BIRDS are THE problem for manned aircraft.

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The other day I sat next to a woman who has a profound fear of flying. I wanted to comfort her, so I said, "Don't worry, we're not gonna' crash. Statistically, we got a better chance of being bitten by a shark." Then I showed her the scar on my elbow from a shark attack. I said, "I got this when my plane went down off of Florida." - Dennis Regan