Jan '96: Reformatted to new FAQ standard. No new data entered. October '94: Updated AstroCam section with "Sticky Shutter" discussion. Updated "Adept" section with new products. Updated "Transolve" section with review from recent "Sprocketry". August '94: Added "Night Flying" section. Updated hombrew still camera section based on NARAM 36 inputs. June '94: Added reference to "Microbats" project. Added "Alternative Boosters" to Astrocam section. Updated some camera references. April '94: Re-wrote section headings into "Q&A" format, minor editing throughout. Split off "Guidance Systems" into separate (new) Part. Renumbered to "Part 5" as part of FAQ reorg. Added table of motor "theoretical performance" in Astrocam Section. Jan '94: Minor addition to camera introduction
Introduction Flying sport rockets is fun. Flying competition rockets can be exciting in the heat of battle. Scale models (my favorite) can be as much of a challenge to research and build as they are to fly. But if you want to do something "real" with your rocket, you've got to fly a payload. This also provides you with a good response to the perpetual question from the great unwashed masses when they ask "so, what's it do?"
13.1 What commercial camera products have been developed over the years to work specifically with rockets? Camroc The first purpose-designed rocket camera. Designed by Estes and sold from 1965 to 1974. A marvel of simplicity, it was patterned after several homebrew cameras of the early '60s (see 5.1.2). It was simply a cylindrical body that held the film topped by a hemispherical nose that was flattened off to accept the optical window which the forward facing lens looked through. One shot per flight on "Astropan 400" (Kodak Tri-X) cut into a 1 1/2" dia. round negative. Easy to process at home. The film had to be push processed to 1200 ASA (officially, though most home developers went to 1600). Extremely valuable on the collector market. [Note: Don't write me asking how much your old Camroc's worth. Bob Sanford (firstname.lastname@example.org) tracks those sorts of things - JH] Greg Smith (email@example.com) describes some of the various hacks of the Camroc: "At one time there were quite a few homebrew modifications to the Camroc floating around. Most popular was substituting a 3-element glass lens from Edmund Scientific for the standard plastic lens; it gave much sharper and better color-corrected results. I have also seen a wide-angle variation with yet another Edmund lens that required cutting the forward body section of the Camroc down to a much shorter length. As someone pointed out at the time, the Camroc lens was a short telephoto relative to its film format. It doesn't make sense to send a rocket up as high as possible and then use a telephoto lens to get a SMALLER angle of view; it's a wide angle you really want, so you can get more in the picture from a lower, easier-to- aim flight with a smaller motor and less risk of losing the camera. Several people flew color slide film in the Camroc, but high-speed color films were pretty terrible at the time; the ASA 1600 print films available today would probably work very well in it." Cineroc Estes' second foray into camera payloads, the Cineroc was *much* more sophisticated than the Camroc. This was a full bore 8mm movie camera crammed into a package not much bigger than its predecessor (although more aerodynamic). Introduced with much fanfare in 1969, it lasted only 5 years before its plug was pulled in 1974. The lens looked aft via a hooded mirror and it shot ~15 sec worth of flight time at 2X speed (30 sec projec- tion time). At least that's what the spec says. In reality, most Cinerocs ran in the 18 - 20 fps range which is more-or-less normal speed. The film was a Kodak ASA 160 instrumentation film on a polyester base which was probably adopted because it was the only daylight- balanced Super 8 film available. The Cineroc used a custom film cartridge meaning that you either used the Estes processing service or went to a custom lab. It could be developed at home using a Kodak E-4 developing kit, but this was *much* more trouble than most modelers would want to go. Gary Rosenfield, now president of Aerotech/ISP, made a name for himself by coming up with a significant hack on the Cineroc that both reduced its diameter and increased the film capacity. As detailed (somewhat sketchily) in the V 14, N 1 (July 1974) issue of the Model Rocket News, Gary took the basic guts of the camera (lens/film gate/geneva transport plus motor and batteries) and put them in a BT-55 tube with the mirror hood outside as usual. He extended the tube fore and aft enough to hold 50' of film (a full cassette worth) in random storage, i.e. no spools. The film simply ran from one compartment, through the gate and into the other compartment. While this made the system much more difficult to reload in the field, you could now have the film developed anywhere, provided you bothered to rewind it back into the standard cassette afterwards. The photo of "Wild Man Rosenfield" that accompanies the article is probably suitable for blackmail :-) The official reason for its early demise, still lamented to this day, was that the small electric motor it used went out of production. However, in a conversation with Mike Dorffler (the designer) he revealed that the product was killed by a combination of events that occurred over a very short (2 month) period in early '74: the motor went out of production, Eveready stopped making the tiny "N" batteries, Kodak changed the formula of the film which couldn't be accommodated by the custom lab doing their processing and, the coup de' gras, a technician dropped the mold for making the custom lens. Some Cinerocs are still flown today 20 years later. The size "N" alkaline batteries, much better than the original carbon-zinc ones that Estes supplied, are widely available now; and the new film stock (which is available off the shelf, not special order like the one Estes originally chose) is sharper and less grainy than the old stuff. Both of these actually make for easier and better Cineroc results today than when it was first introduced. You do still need a custom film lab to deal with the nonstandard lengths of 8mm film, however. AstroCam 110 Another Estes product and something of a combination of the previous two. Reverting to the still format, the AstroCam was designed around a stock 110 cartridge. It took multiple shots per roll of 400 speed color print film, but still only one frame per flight. The lens looked out through a hooded mirror (like the Cineroc) but this time looking forward (like the Camroc). Image quality was marginal due to the plastic lens and small format, but the film can be developed anywhere (although the prints are reversed). A very long lived product, it lasted from its 1979 introduction until early 1992 when, for reasons known only to themselves, Estes canceled it. Public demand was great enough that they re-introduced an "improved" version in early 1993. Said improvements consisted of a better lens for a sharper image, a one stop increase in aperture (so it can use the much more available 200 speed film) and pre-assembly of the lens and sprocket. Perhaps the biggest improvement of all was that they dropped the price by $10 :-) California Consumer Aeronautics Super 8 Movie Camera This San Diego, CA, company sells a very small Super 8 movie camera suitable for HPR payloads, but it's not a ready-to-fly system. Cotriss Technology (San Jose, CA) specializes in rocket photography, and sells a complete HPR still camera system (including rocket) called the Observer. Please see address section for complete addresses of these companies. Note: CCA has announced that it is dropping all of its rocketry products, but they should still be able to point you in the correct direction regarding the camera.
13.2 Are there any tips on building and flying the AstroCam 110? The AstroCam is the source of continual threads on r.m.r. The following is a distillation of nearly half a megabyte worth of AstroCam discussions I've archived: GENERAL TIPS Jim Cook (firstname.lastname@example.org): Some observations from myself and C.D.Tavares (email@example.com): * The film is quite grainy, hence a lot of people move on to 35mm cameras. * Underexposure is a problem - the pictures are lousy if you launch in anything other than bright sun. Of course, there's also the usual problem of forgetting to open the safety shutter before launch. * Overexposure is a problem several ways: - The shutter cord can get tangled in the shroud lines, taking multiple exposures or one long exposure. - A hard impact can take another shot. At the least, landing impact will close the safety shutter making you wonder if you forgot to open it before launch. - Problems with sun and heat on the pad make some folks drape it with aluminum foil until final countdown. - Adjustments on the pad are always a source of causing the shutter to go off on the pad. * Chris suggests advancing the film before take off and advancing it after landing. Yes, it wastes film, but you tend to not use all the shots anyway. I believe that Kodak only makes 24 shot rolls of ASA 400 110 size film. SOME THOUGHTS ON FILM John Viggiano (firstname.lastname@example.org): Modern C-41 stocks have a 2-step under / 3-step over exposure latitude. The material has so low a contrast that little information is lost; the effect is primarily a density shift which can be removed during printing. Jack Hagerty (email@example.com): K-Mart 200 speed print film (which is made by 3M, and sold under many different "house" brands) makes an acceptable medium. It's cheap, comes in 12 exposure rolls, and has enough latitude to give acceptable exposure. STICKY SHUTTER PROBLEMS Many r.m.r readers report sticking shutters in their AstroCams. This ranges from a completly stuck shutter that binds so tightly that it won't move, to a mildly draging shutter that causes motion bluring and overexposure. During construction of the camera, it is essential to monitor the shutter movement after every step. It seems that a camera too tightly constructed binds the shutter. Even though the current release of the AstroCam have the lens and part of the shutter pre-assembled, it is still possible to get the assembly too tight. It is also important to use *liquid* plastic cement on this assembly. The liquid allows you to dry fit the parts to their proper place and apply the cement afterwards which wicks into place. The gel-type cements commonly used with model building requires that the parts be dis- assembled after the dry fit to apply the cement, and they might not go back together exactly same way the second time. Also, the "strings" and "oozes" from gel cement can more easily contaminate the shutter slide. A less common, but well documented problem is the clearance between the shutter string and the film cartridge. Check the knot that ties the shutter string to the shutter. On some AstroCams it tends to rub on the bottom of the film cartridge when the latter is fully seated causing the shutter to hang up after release. A mildly dragging knot causes overexposure but in more severe cases you get either a totally blank or totally saturated negative depending on where the shutter stalls. Since this is the case with my own (original release) AstroCam, I now routinely carve a flat into the bottom of the cartridge with a hobby knife before installing. ENGINE COMBOS Jim Cook (firstname.lastname@example.org): Given a well constructed AstroCam, a C6-7 will produce a good shot. However, an Estes D12-7 will produce a horizon shot or blurry shot as it is still in motion (this was reported in the Model Rocketeer about 10 years ago). A little weight will cure this without negating the effect of the D motor. I've also used AeroTech D21-10 or E25-10 can work well, though I wonder if a 10 second delay tends to produce horizon shots with an E-powered launch. Dan Wolman tried an F-based launch which resulted in a blurry image (again, probably too short a delay), so he tried an F25-10 and lost it to wind/thermals. Harry C. Pulley (harry@aeshq.UUCP): With C6-7 engines, I have found that vertical flights range from 550-650 ft in altitude. For horizon shots with C6-5 engines, the altitude was a little better (photo taken earlier in descent) maybe 600-700 feet. Jack Hagerty (email@example.com) [talking about small field flying]: Estes B6-4's give horizon shots Quest B6-4's give sky shots Estes B4-6's give ground shots from ~30' up (real heart stoppers!) Estes B8-5's give reasonable ground shots Bob Wiersbe (firstname.lastname@example.org): A B6-4 will work, but it's hit or miss whether you'll get a ground or sky shot. D21-10's are superb, though expensive. A C6-5 will give you a horizon shot (if you're lucky). The C6-7 is almost guaranteed to give you a shot of the ground. Robert Zingarelli (email@example.com) decided to do some theoretical analysis to see what the differences actually were between the various motors. He reports: I simulated all of the plausable engine combinations for AstroCams and the two matching boosters Estes offers [the standard "Delta II" which has an 18mm motor mount and the "Maniac" which uses the same size body tube but a 24mm motor mount - JH] All calculations were done at STP atmospheric conditions, and all engines are standard Estes, with thrust curves from their data sheets. The results are arranged in order of increasing altitude at ejection. Entries in the "combo" column are booster/engine, with D for the Delta II and M for the Maniac. The drop time from apogee (Tdrop) and ejection velocity are the relevant parameters in determining if a combo gives a vertical, horizon, or sky shot. Combinations marked with a * are ones I've tried, combinations marked with a '+' have been reliably reported (in Bank's book Advanced Model Rocketry or here in the FAQ). Rocket/ Apogee ej alt ej vel Tdrop Engine (ft) (ft) (mph) (sec) Comments ------------------------------------------------------------------------ D/B8-5* 197 136 -41 2.0 almost always vertical shots D/B6-4* 209 192 -22 1.0 mix of sky, horizon, & vertical M/C6-5 377 222 -39 1.9 -CAUTION- 19 mph liftoff! D/C6-7* 492 357 -57 3.0 always a vertical shot D/C6-5+ 496 479 -22 1.0 similar to B6-4, but more variation. M/D12-7+ 699 633 -43 2.0 reportedly blurry, some horizons M/D12-5+ 701 701 -0.7 0.0 Banks says gives horizon shots, but probably a bad bet. M/E15-8 1094 1016 -47 2.2 M/E15-6 1096 1095 -5 0.2 The key thing here seems to be the drop time. If it can drop for 2 or more seconds, you get a vertical shot; in the 1 second range you get horizon shots. It looks like the E15-8 will mostly give vertical shots, but remember that there's a +/-15% variation in delay charge lengths, so you'll probably get some horizon shots as well. Larry "Mr. Simulation" Curico (firstname.lastname@example.org) checked Robert's figures and noted: Only the B6 AstroCam changed enough to be worth even mentioning - 192 feet instead of 209 feet. This is ballpark back-of-the-silicon-envelope figuring [but] it's good to see folks doing numbers. REVERSING THE CAMERA From: Chris Tavares (email@example.com) The original article [on reversing the AstroCam] was "Retrospective Rocketry" in a 1980(?) issue of Model Rocketeer. It's since been reprinted by Estes in one of their Model Rocket Newses, which you should be able to get. It may also be available from NARTS. From: Jack Hagerty (firstname.lastname@example.org) Speaking of the MRN, the V34 N1 issue (Spring, '94) contains a couple of articles showing a total of four different designs for reversing the camera. They are all in considerable hand-holding detail, in keeping with the MRN editorial style :-) [Editor's Note: In his book Advanced Model Rocketry, Michael Banks (email@example.com) shows a couple of reverse-AstroCam hacks including a "stereo" version incorporating two cameras hanging on either side of a large body tube. This, IMHO, would not produce any stereo effect at altitudes above 50' due to the minuscule baseline (the OD of the body), but would double your chances of getting a shot. Additionally, Tom Beach (firstname.lastname@example.org) has a dual, rear-facing AstroCam (tandem) which he flew at NARAM 34, a photo from which was published in the Sept/Oct '92 AmSpam - JH] ALTERNATIVE BOOSTERS The Delta II rocket that comes with the AstroCam (actually, the booster is unnamed in the current release) is stable, durable and hardworking. It does, however, limit you to a single 18mm motor which restricts your altitude to about 600 ft if you're using black powder or about 1,000 ft if using a composite (e.g. the Aerotec D21). As previously mentioned in "ENGINE COMBOS" above, the Estes "Maniac" will fit the AstroCam which will let you fly a single 24mm x 70mm motor and get up to 1,500 feet or so. The reason you can't just plop the A/C onto just any Estes rocket is that it was designed around an old Centuri body tube size (Series 13) which is just a tad larger than the Estes BT-55 (1.30" dia vs 1.28" for the BT-55). This tube is not generally available from Estes (it has no catalog number) but is sometimes referred to as "BT-56" internally. BT-55 has been made to work if you peel one layer from the inside of the tube, but it should be re-enforced using CA or some other glue to prevent buckling. It has been reported ("Section Soundings," April, '94 HPRM) that the FSI tubing size RT-12 is a very close match to the Centuri Series 13 and that the FSI "Echo" makes a nice two stage AstroCam lofter. CLEANING THE CAMERA From: Jim Cook (email@example.com) There is one hint that I don't think has been mentioned: Bring a few Q-tips to the launch field in your range box. Use them to clean the lens before launch. From: Jack Hagerty (firstname.lastname@example.org) I believe a #1 Camel's hair brush is a better cleaning tool than a Q-tip for the mirror. Since the Q-tip doesn't bend like the brush bristles do, the surface pressures on that front-surfaced mirror can be quite high. I'm not sure what material is used for the "cotton" tip (rayon?) but some synthetic fibers can be very abrasive. To prevent dust from collecting on the mirror, I store my AstroCam/Delta horizontally from a string with half a paper clip at each end hooked into the launch lugs. Some people bag the camera in a plastic produce bag. GETTING THE PHOTOS PRINTED "RIGHT" Jack Hagerty (email@example.com): Find a 1 hr photo place that does 110 film then have the film processed normally. This means, of course, that the images will be reversed. If any of the flight (or ground photos for that matter) came out well, then hand the negatives back to the service droid and ask him/her to make some reprints with the negative flipped. The key is that you're talking to the person who'll be pushing the buttons so you can watch them do it. If there's no one else ahead of you in the processing queue, they can do this while you wait (it only takes about 5 minutes) and if they screw it up, you can refuse the print and they'll try again. Jim Cook (firstname.lastname@example.org): Those of you with the right equipment can scan an AstroCam photo into your computer, then properly reverse it electronically if you have Adobe Photoshop software.
13.3 I don't want to just buy a camera system, I'd rather design and build my own. What's already been done and what's available for "homebrewers"? Still Cameras The earliest hobby type rocket with a camera was reported on in the March 1983 issue of The Model Rocketeer (the predecessor to Sport Rocketry mag) in the article "King George VI's Rocketeers." As Chris Tavares (email@example.com) reports: "A school group in Scotland formed what is possibly the first model rocketry club [in the late '40s - JH]. Of course, there were no commercial model rocket motors available, but they used pennywhistle fireworks motors. The group's advisor designed and flew a camera-bearing rocket with which he took several photos of a nearby loch. The motors were pre-manufactured by professionals, used once, and thrown away. The airframes were designed by the modelers, and made out of paper and light woods. It's as valid an implementation of 'model rocketry' as what goes on today in eastern Europe." According to Stine (Handbook, 2nd Edition) the first true "model rocket" (in the NAR Safety Code defined sense) camera payload was flown by Lewis Dewart in 1961. Lewis simply strapped a tiny Japanese novelty camera to the side of a model. The shutter was tripped by the nose cone separating. Shortly after that, Dennis Guill upped the sophistication by taking the shutter and lens of a similar camera and mounting it on a plastic tube that just fit inside a rocket body tube with the lens facing forward. It used sheet film cut into a circular negative and the cocked shutter was released by a lanyard (a shoelace!) at ejection (sound familiar?). It was an aerodynamic nightmare, but Estes saw enough promise to develop the concept into the Camroc. The present wealth of lightweight, autowind cameras on the market makes it relatively easy to design a sequence camera that shoots a whole roll of film on a flight. A crude-but-effective setup was developed by Peter Alway and described in Vol 3, No 2 issue of T-5 (the HUVARS newsletter). Peter took a cheap autowind 110 camera and came up with a simple arrangement of a motor, a stick and some bits of wire to repeatedly trip the shutter. This setup was flown on an "E" motor. A similar, but more sophisticated, system was detailed in the March/April 1992 issue of AmSpam. Steve Roberson designed his system around HPR to give him power to boost a high quality 35mm camera to significant altitudes. He took a relatively expensive Olympus autowind camera and triggered it with a very solid (but simple) cam-and-lever mechanism. A nice feature of this camera is that it automatically rewinds the film into the can at the end of the roll which would enhance its survivability in the event of a crash. A tribute to Steve's design and flying skills is that the camera and rocket were retired, intact, after 22 High Power flights (H & I motors). Some more photos of/by Steve are in the March/April 1993 HPRM. The same issue has some killer aerial photos by Steve Lubecki as part of the "Danville 8" article. A follow-up article in the August, 1993 AmSpam details the next generation of this project which increased the size and sophistication significantly. A variation on this theme was introduced by Bob Hart at NARAM 34 in Las Vegas which he brought out again to NARAM 36 in Houston. He uses a compact 35mm camera which comes equipped with "sequence" mode (i.e. it keeps shoot- ing at ~1 fps as long as the shutter is pressed). Additionally, the shutter is electronic so that all it takes is a contact closure to activate (no more moving parts). Bob had switches at several places on the rocket to trigger the camera either as it cleared the launch rod, or at payload separation. He also used a recovery harness to keep the lens pointed at the ground during descent. Other cameras at NARAM 36 included Bob Alway (firstname.lastname@example.org) who flew a system identical in concept to Bob Hart's but somewhat different in execution. Going the simpler (read "crash affordable") route. Ted Mahler (email@example.com) made several flights of his adaptation of a Kodak Disk camera. Thanks to the miracle of 1 hr photo development shops, we were all able to enjoy the shots that evening! Roger Wilfong (Roger.Wilfong@umich.edu) has isolated at least one make and model of 35mm camera that is easily adapted for flight: "My favorite is a RICOH Shotmaster AF Super. It has an electric switch remote shutter release and a 'continuous' program mode. You set this mode and the camera shoots a whole roll of film when the shutter release is held down (or the remote contacts are shorted). The camera fits in an LOC 3" tube and even rewinds the film at the end of the roll." A very involved HPR camera project was covered in five parts by HPRM over the 5 issues of 1992, but is too involved to summarize here. Parts 1 and 2 were reprinted in the March/April and May/June 1993 issues, respectively, so that folks buying it off the rack could catch up (HPRM didn't "go public" until halfway through the series). Tad Morgan (firstname.lastname@example.org) found another photo payload design which was a good example of cross pollenating between hobbies: "In the June '94 issue of "Circuit Cellar INK," a projects oriented electronics magazine, there is the article "Aero-Pix Aerial Photography System" that would appear to have some promise for medium-high power rocket use. It's a microcontroller based system & uses a better timing system than the typical 555 chip. It also details the mods to the Canon Snappy LX, a camera that has an electronicly switched shutter. "The main modifications that are probably necessary for rocket use are to the software. The system was designed to be used with a weather balloon, and the sequence starts a minimum of one minute after release & a minimum frequency of one minute. I imagine though that the microcontroller should make the change to more suitable timing quite easy. Several r.m.r readers have announced projects to convert cheap film-box cameras into payloads, but none have posted their results yet. One ambitious soul (name please!) is even attempting to add film advance/shutter trip mechanism to make a sequence system. We'll keep you posted.
13.4 What other movie camera payloads have been flown and are now used? The first model rocket movie camera was flown by Charles & Paul Hans and Don Scott in 1962. A heavy spring-wound Bosley 8mm camera was crammed into a payload section and lofted by an early "F" motor. The story is still recounted by Stine in the most current edition of the Handbook. (Note: Paul Hans currently works for ISP/Aerotech). Due to the greater difficulty of adapting a movie camera, and relatively easy access of Cinerocs, not too many homebrew movie cameras have been flown, compared to still cameras. The amateur "AmSpace" project outlined in the April '94 issue of HPRM contains an 8mm film camera to back up its live video downlink. This will be carried to 80 KM (over 260,000 ft)! California Consumer Aeronautics (San Diego, CA) sells a very small Super 8 movie camera suitable for HPR payloads, but they have announced that they are dropping all of their rocketry products. Still, they should still be able to point you in the correct direction regarding the camera.
13.5 What about Video? Camcorders are getting so small that they should work. How hard is it to adapt one? How about broadcasting the image back? This is a new area with much work going on, and some early successes to report. There are two ways of returning video from a rocket: record and transmit. Recording Cameras Following the lead of film cameras, attempts have been made to fly stripped camcorders (using HPR, obviously!) to record the flight while on board. Video tape recording, however, is a very delicate technology and the accelerations encountered in rocket flight jiggle, dislodge and otherwise move the tape all over the recording heads in a disruptive manner. To date, I have only one report of someone making this work. Stu Barrett (email@example.com) reports: "At a recent San Antonio Prefecture launch, Randy Reimers (an expert video technician) had a Sony camcorder with the camera separated from the transport via a wire harness. He had the transport installed so that the tape was vertical to the ground. That seemed to keep the tape on the tape heads. He did say that under the acceleration of a K550, there was a slight herringbone pattern on the tape during the boost that he attributes to vibrating tape due to high G's. The J415 did not have this phenomena." [Moderator's note: Both Stu and I agree that this sounds sideways. One would think that the tape transport should be positioned so the tape runs horizontal (WRT the acceleration) over the heads. The explanation seems to be that the grooved pulleys and tape guides have no problem keeping the tape tracking correctly, even at 10 or 20 gees (tape's pretty light!), but if you place the cassette with its spools vertical (i.e. the tape horizontal) the tape tends to pull freely out of the cassette under acceleration and tension is lost. No tension, no picture - JH] Transmitting Video Transmitted video has had more frequent success, but complicates the process by adding a whole new technology. While the components that ride in the rocket have no moving parts, you must add transmitters and antennae to your vehicle, plus receivers and recorders to your GSE. License-less video transmitting is allowed by the FCC, but the power limitations raise more problems. Omni directional transmit antennae are easy to track, but the signal strength drops off *fast* (inverse square law). Directional antennas concentrate the signal, but require that you track the rocket, or hope that it doesn't go too far off course! A good, but somewhat superficial, article on transmitted video appeared in the July '92 issue of 73 Amateur Radio Today. Being a radio hobby magazine, it concentrated on that aspect (and assumed you know a bit about it) and left the rocket parts at sort of the gee-whiz level. The system transmitted with 6 Watts (the developer was a licensed ham) and returned a good, clear picture to an altitude of 1,200 ft. The rocket was an HPR (no details given) but this was just the checkout vehicle for the transmitter hardware which is slated to go into an LOX/Kerosene amateur rocket with a design altitude of 200,000 ft. The Jan/Feb '93 issue of HPRM had two articles on broadcast video systems; both, coincidentally, being homebrew reworkings of the Lionel "railscope" miniature CCD camera. While being admittedly low-res, the systems can be made quite light. The version by Dan Green had a fight ready weight of only 3 oz which makes it capable of being flown by a "C" motor! The May/June '93 HPRM has a fairly lightweight article on a video transmitter project called the "ICU2" (get it?) The amateur "AmSpace" project outlined in the April '94 issue of HPRM contains a live video downlink as part of its sizable instrument package. Commercial Grade Products If you feel like dropping bigbux on the hardware, Hans Schneider (Bordentown, NJ) runs a much improved ad (compared to his previous one) in HPRM offering an HPR based color/sound video broadcast system (including rocket). Hans Schneider Transmitting Video Rockets 42 Valley Forge Road Bordentown, NJ 08505 Jim Cook (firstname.lastname@example.org)informs us that Supercircuits in Austin, TX is a good contact for miniature video cameras (B&W and color), transmitters, and receivers. Note that the operation of this transmitter requires a ham radio license. See the address section for the address of these companies.
13.6 What sorts of data transmitters are available for rockets? What's been flown in the past? According to the Stine Handbook, the first purpose-designed model rocket telemetry transmitter was designed by Bill Robson and John Roe. The unit broadcast on the Citizen's Band and was first publicly flown at NARAM 2 in 1960. It was a simple multivibrator that put out a continuous tone which could be modulated by a sensor, but what to do with the wavering tone it sent back was left as an exercise for the reader :-) Stine still includes the schematic for this device in the current edition of the Handbook, although he finally admits to it being "a very old design." Foxmitter Using the same basic encoding principle (and still broadcasting on the Citizens' Band), Richard Fox designed the "Foxmitter" which was described in the May thru December '69 issues of the old _Model Rocketry_ magazine. An improved version, the "Foxmitter-2" was detailed in the June '70 thru Jan '71 issues of that same journal. The thing that made it an advance over the Roe/Robson design (and the reason it took so many issues to describe) is that the Foxmitter used a basic transmitter module into which multiple sensor modules could be plugged (one at a time). The sensors covered included a basic tone module (for tracking purposes), temperature, humidity, acceleration and even a microphone! A smaller/lighter Foxmitter III was described in the Sept '71 issue. In a couple of related articles in the Aug/Sept '70 MRM, Alan Stolzenberg used the Foxmitter as the basis for his "Bio-1" design which involved a very clever respiration sensor to monitor the flight subject from order Rodentia (see Section 4.3 below). This was, of course, before launching mammals and other higher orders fell into disfavor in the hobby. Transroc In a case of deja-vu all over again, Estes took a well developed homebrew design, in this case the Foxmitter, and turned it into a commercial product. This time, they also borrowed a page from the Heathkit notebook and let the customer do the assembly (it was also available pre- assembled). Like the Foxmitter, the Transroc used sensor modules to let you mix 'n match the parameters you wanted to measure. Available were the basic beeping tone module (aka "Rocketfinder" mode), a temperature module, spin rate module and a microphone module. The Transroc announced the beginning of the Estes "Rocketronics" line with its introduction in 1971. It also quietly marked the end when it disappeared with the 1977 catalog. Note: The current "Transroc II" sold by Estes is NOT an RF transmitter! It is an audio beeper designed to help you find your model after landing. It can be heard by the "naked ear" several hundred feet, but that can be extended by using the ground unit which is a highly directional microphone with a narrow pass filter on an amplifier. Current - Adept Rocketry in Broomfield, CO sells a large range of electronic products including both transmitters and data loggers. I've grouped them together in the next section.
13.7 I don't want to bother with ground based receivers and recorders. What sorts of Data Logging products are available? The rise of the microprocessor coincided almost perfectly with my hiatus from the hobby. If anyone out there has documented examples of the first micro-p to be flown in a model or HPR, send it to me and I'll include it here. The October 1990 issue of Radio-Electronics magazine had a very long and detailed article by John Fleischer on an altimeter payload based on a solid state pressure sensor. The system consists of three parts: an analog board with the sensor and signal conditioning, a CPU board and a display module. The latter stays on the ground and can read out the data in either selected peaks (shades of the beginning!) or do a 1/4 speed "slo- mo" playback of the entire flight. The article contains schematics, parts lists and even board masks for etching your own. For more info on this device, see "Transolve Corp." below. The April, '94 issue of HPRM has a remarkably detailed article on the "Microbats" project. This is a very large ("M" motor) HPR project that is *very* heavily instrumented. The Rocket Data Acquisition System (RDAS) consisted of a 35mm camera, altimeter, 2-axis accelerometers (horizontal and verticle) plus a sophisticated timer-based control system (see Part 6 for more on timer-controllers). The article includes theoretical predicitions and compares it to the actual flight data. In that same issue there is an introductory level article on an amateur rocketry project called "AmSpace" which is designed to put the first non- professional payload up to orbital altitudes (80 KM or 50 miles). The payload will contain a significant amount of data logging of internal parameters. There are accelerometers which will be integrated real time to give velocity and altitude information, sensors to monitor pressures and temperatures in the propulsion system, a GPS to track the rocket's position relative to the earth and a magnetometer to control the steerable paraglider chute to help return the payload to the launch site. The data logging will be complemented by an RF data downlink plus amateur TV. Along with all other aspects of the computer industry, small "garage" type companies dominate the computer rocket payload industry. Following are a few data logging payloads that I have information on. As usual, caveat emptor: Flight Control Systems Flight Control Systems of Camp Hill, PA sells a very sophisticated system called the FP1 (Flight Pack One) Data Logger. This consists of a complete computer system on a 1.6" wide x 11" long board into which the sensor board plugs. The system not only logs data from the sensors, but comes with a development system so that you can write your own programs to start/stop data logging based on time or other flight events (e.g. staging). The ground support software (all PC based) is quite extensive consisting of archiving software (to upload data from the FP1 to your PC) and data analysis software to crunch numbers once it's there. The standard sensor board has altitude, velocity and temperature sensors on it, but they also provide a prototype board for designing your own. The sensor board can be remote mounted from the CPU board. Price for the FP1, sensor board and software is a rather substantial $300. Note: this company has not been answering its mail, according to some r.m.r posters, and may be out of business. Transolve Corp. This Cleveland, OH, company sells the "A2 Micro Altimeter" which sounds suspiciously like a production version of the Radio-Electronics system described above. John Viggiano (email@example.com) clarifies: "Many of the articles in Radio-Electronics are thinly veiled advertisements. In this case, it would appear that the author was writing on behalf of Transolve, in order to sell the kit." John is correct, especially considering that the author is the CEO of Transolve :-) A detailed review of the A2 was printed in the July/August issue of Sport Rocketry magazine. Adepet Rocketry Adept Rocketry, Broomfield, CO - Has quite a line of electronic products including peak reading & continuous altimeters and on-board computers. A few of these are reviewed by Tom Beach (firstname.lastname@example.org): "Entry level is a $70 altimeter. Relatively small, you launch it into the air, and when it returns it will be beeping out the maximum altitude (beep-beep-beep ...beep-beep...beep = 321 feet). A $120 version will log the altitude data into EPROM for later recovery and downloading. They also have] on-board computers (four models, most with built-in altimeters)." "Telemetry/Tracking Transmitters and Receivers - Prices on transmitters are expected to be in the range of $10 to $30, with receivers reaching higher prices. However, at least one low cost receiver is planned, and in a few cases you'll be able to receive data on a standard FM radio. Ground Support Devices will be available for decoding and recording data in the field, and PC compatible software is being written for plotting and analyzing the recorded flight data." Finally, we have from the r.m.r address list the following entries on which I have no info outside of the tag line in their list entry: Langley Autosystems in Sunnyvale, CA is listed with "Datastick on-board computer" High Technology Flight in Ypsilanti, MI sells "Electronic Payloads". [Moderator's note: There are quite a few electronic timers, beepers and even sophisticated micro-p based flight controllers sold by several companies. These are usually used to control staging, recovery deployment and aid in the recovery itself. While of the same general nature as the electronic payloads just described, they are not technically payloads, but rather part of the carrier rocket itself. They have therefore been grouped togehter in Guidance Systems, since it seems a more appropriate fit.]
13.8 Has anyone actually brought stuff back from a rocket flight? This final type of data collection is practiced only rarely by professionals. True, some satellites are designed to be returned for study (the LDEF is a notable example), but outside of Earth orbit, the only unmanned "sample return" missions have been some moon rocks brought back by the Soviet "Luna" series. I have only one documented example of sample collection by model rocket. In the anthology Advanced Model Rocketry complied by Michael Banks (email@example.com) there is an entry by Eric Nelson describing a system used to collect atmospheric pollen and spore samples. It used an Estes Omega to loft a sampler consisting of a hollow nose with a clever arrangement of springs and marbles acting as check valves.
13.9 What about biological payloads? Can I fly mice or toads? The official position on biological payloads can be summed up in one word: Don't. The perfectly reasonable rationale here is that this is an educational hobby and you really aren't going to learn anything new by torturing your pet gerbil or lizard to see if he'll survive (and if he doesn't, how will you know what killed him? Launch shock? Burnout deceleration? Recovery deployment? Impact?) With that disclaimer out of the way, though, we must admit that there are other reasons for launching living things, as any 10 year old can tell you. If you have to do it, though, try to stay outside your own Phylum :-) No one's going to get too upset if you launch a few plant leaves (Some HPR guys even use lettuce as recovery wadding) and few are going to risk the hypocrisy of objecting to a gastropod-naut after killing hundreds of them with snail pellets the week before. Be careful if you start venturing into the Chordates, though. While I'm sure there have been more rocket riders from Class Insecta than all other bio-payloads combined, stay out of Vertibrata. Anything with a backbone is a definite no-no.
13.10 Are there any payloads I can fly that really don't *do* anything? You know, just for fun. Contest payloads include.... NAR standard payload It wasn't long after the founders of the hobby had the propulsion and airframe parts of the system sorted out that they wanted to do "something else" during contests. Thus was the idea of lofting a "dead" weight born. The first NAR standard payload was a slug of lead 3/4" in diameter weighing 1 oz. Later, this was changed to being a cylinder filled with sand. The official description (from the Pink book) reads: "The standard NAR model rocket payload is a non-metallic cylinder filled with fine sand, with a mass of no less than 28 grams [1 oz]. This cylinder shall be 19.1mm [3/4"] in diameter and 70mm in length." Tripoli water payload As with everything else in HPR, the standard contest payload (even though Tripoli doesn't officially run contests) is larger than life :-) They decided that if the standard NAR payload is one ounce, then the standard Tripoli contest payload should be one pound. Rather than using lead or sand, though, they upped the difficulty by using water. Also, there is no standard container for the water, just a requirement that the airframe be at least 2.25" diameter at some point and be able to hold 16 fluid ounces of water. The payload compartment is weighed both before and after flight to make sure that you didn't leave any "vapor trails" during flight. One added wrinkle is that everyone must use the same 36" chute, one of which is provided to each contestant. Eggs According to Stine, the idea of flying raw eggs is attributed to Captain David Barr of the USAF Academy in 1962. Originally, this was used as a qualification test to see if you had the skills to launch a biological payload with a good chance of getting it back alive. It quickly took on a life of its own, so to speak, as a competition. The "official" raw egg is described in the Pink Book as: "a raw, USDA Large hen's egg with a mass of no less than 57 grams and no more than 63 grams, and measuring no more than 45mm in diameter." Credit for the first successful eggloft is given to the same Hans/Scott team that flew the first movie camera (q.v.) Another 'fun' payload area includes "things you eject". Generally speaking, the hobby discourages ejecting things out of your rocket (other than the recovery system, of course!) so as to not appeal too much to the "warhead" mentality that we run into all too often. However, there is great crowd pleasing effect to be had in dropping a bunch of colorful "ejecta" for everyone to chase. Variations on this type of rocket have been around for some time. Plans for "concept" rocket called "The Purple People Eater" by Ken Brown were published in the December, 1980 issue of Model Rocketeer magazine. The model drops various types of streamers and "flutterers" at ejection. A larger version of this model was flown by Chris Tavares (firstname.lastname@example.org) off of NARAM 34's sport range in August, 1992. Expanding on the concept, the "ZIA Spacemodelers Sport Design Notebook" compiled by Tom Beach (email@example.com) contains a design by John Pratt called "Bombardment." Capitalizing on various novelty toys available on the market, this model carries three foam gliders (Guillow Co. "Delta Streak") as parasites and has a modified egg capsule crammed with all sorts of goodies. Included are three "Pooper Trooper" parachuting army figures, six "Re-entry Vehicles" made from strips of trash bag taped to rubber washers and a hand full of "Penetration Aids" (black confetti) thrown in for good measure. Once again Estes came along and formalized the idea with a production version they call "Bailout". This is nothing more than a wide diameter rocket with a body tube big enough to hold an action figure (e.g. GI Joe). The kit includes an extra parachute for the figure, but you have to supply Joe. Despite the appearance, the figure does *NOT* leave via the "hatch" on the side. That's just a decal. He ejects out the top with the regular recovery system. Reports on r.m.r of success with this model have been mixed, mostly because the recommended "B" motors are awfully wimpy to loft a 100+ gram model (Joe usually prangs before his chute unfurls), and the recommended "C" motor is the "CATO-master" C5-3. Speaking of CATOs, Estes has a model of the same name which sort of fits in this category. While it technically doesn't eject anything, it does break apart in the air and comes down in pieces. Estes once thought of dropping this from their lineup due to poor sales (it goes against the grain of most rocketeers who do everything in their power to keep their rockets *together* :-) but having witnessed them, I can say they're great crowd pleasers! Back on the ejection front, John Viggiano (firstname.lastname@example.org) reports: At a November, 1992 Tripoli launch the announcer said, "This one's going to eject a roll of toilet paper." Sure enough, an extremely long yellow streamer was seen coming down. It actually turned out to be a roll of that yellow polyethylene "CAUTION" streamer that you can get at hardware stores for cordoning off excavation sites. He had about a ten minute winding-up job. Finally Buzz McDermott (email@example.com) fills us in on some eccentrics down in the southland: "A DARS member, Jimmy Cleek, has built a 3" diameter rocket he calls 'Tomato Rain'. True to its name, he launches several small tomatoes and ejects them as part of its regular flight plan. He has also ejected candy at an Easter launch. Jack Sprague, also of DARS, has a model in which he ejects up to 1/2 dozen MIRV's at apogee. The MIRV's are the little Nerf-darts you can get at toy stores. Another favorite payload to eject at DARS demo launches is a number of pennies, each taped to the end of a 6" x 1 1/2" crepe paper streamer. Makes for a great demo flight. All variations on the same theme....
13.11 How about some good payloads to fly at night? This is another of those subjects that comes *really* close to falling over into Part 6, because all of the following are used as recovery aids if you launch at night. At first blush, night flying seems really silly. After all, except for the initial glaring brightness of the motor burn, you can't see it. What's the point? It all seems vaguely illegal somehow :-) Bruce Wehr (firstname.lastname@example.org) inspired this whole section when he posted: "Having recently read the FAQ section on payloads, I was a bit surprised by the total lack of discussion on something that has intrigued me for some time: launching at night. "I always thought it would be possible by carrying some sort of bright strobe for a payload. Either ultra-bright LEDs or some xenon flash-tube strobes in a clear payload section. The lack of discussion leads me to believe that I must be missing something unsurmountable." Iskandar Taib (email@example.com) made the first response with his suggestion: "Try Cyalume glow sticks. They're quite visible a long way up, and can be quite cheap (buy them right after Hallowe'en). I usually tape them with clear tape to the shock cord." This is a very common suggestion for night launches, and was included in what is perhaps the definitive article on night flying, published in the April, 1994 issue of Sport Rocketry magazine. In it, author David Sollberger describes several types of Night Illiumination Tracking Equipment (NITE, get it?) including chemical (the Cyalume sticks), high intensity LED's, incandescent bulbs and strobes. They are all evaluated for cost, effectiveness and complexity. Several designs of varying completeness are included. Complementing the NITE article in the same issue is a very complete design for a High Intensity Strobe by Mort Binstock.
Copyright (c) 1996 Wolfram von Kiparski, editor. Refer to Part 00 for the full copyright notice.