FAQ - Frequently Asked Questions

  1. Miscellaneous
  2. Chute Tamer™ Components
  3. Chute Tamer™ Operation
  1. Miscellaneous:

    2. Line up of ready Chute Tamers(tm)
    1. Does the Chute Tamer™ control require the use of additional black powder charges? No, the Chute Tamer™ control uses only the engine's black powder ejection charge to eject the bound parachute out of the rocket's body tube. No additional black powder charges are required. The main parachute is released by heating and melting the fishing line used to bind the parachute. This means that the Chute Tamer™ control can be armed and tested without an explosion safety concern. It also means that the Chute Tamer™ control does not require expensive and hard to get ematches.
    2. Does the Chute Tamer™ control require the use of ematches? No, the Chute Tamer™ control does not use ematches. When the programmed time expires, the electronics send electric current though a small reach of nichrome wire which heats and melts a monofilament fishing line.
    3. How is the Chute Tamer™ control different from Aerotech's Electronic Forward Closure (EFC)? The Chute Tamer™ control is a completely different device, for a completely different purpose than Aerotech's Electronic Forward Closure (EFC). The confusion occurs because both devices use an internal PerfectFlite electronic timer, a G-switch, and a heating element (in the case of the EFC, it is a glow plug). In operation, the EFC allows the user to program the desired delay between launch and ejection charge. The EFC requires a black powder charge. The Chute Tamer™ control allows the user to control parachute deployment.
    4. What is the smallest rocket that the Chute Tamer™ control has flown in? I have flown the Chute Tamer™ control in an Apogee Stonebreaker. This a great 2 inch diameter rocket design with a 24mm motor mount and stable flight characteristics. The Stonebreaker is 28 inches in height with a 2.2 inch diameter body tube and weighs about 11 ounces with the Chute Tamer™ control and an empty engine casing. While Stonebreaker can be flown with black powder engines such as C11 and D12, the added weight of the Chute Tamer™ control requires a minimum average thrust of 17 newtons. I have flown this rocket many times with composite engines such as an E18 (about 1,500 feet) and an F24 (about 2,000 feet). I like this rocket design so much that I scratch built an upscale version with a 38mm motor mount.
      (Right click and "save as" to download my 24mm Stonebreaker Rocksim file.)
      (Right click and "save as" to download my 38mm Stonebreaker Rocksim file.)
  2. CT Components:

    3. Open Chute Tamer(tm) in four positions
    1. Is the heating element dangerous? Not particularly, but the nichrome wire briefly heats to a very high temperature that would burn skin. For this reason the heating wire is located inside the body of the RJ45 plug. Still, it is a good idea not to be touching the open end of the heating element when the Chute Tamer™ control is in operation.
    2. How durable is the Chute Tamer™ control? At the 2007 NY Power launch in Geneseo NY I watched a rocket with the Chute Tamer™ control come in ballistic. (The engine's ejection charge failed.) The rocket buried itself in a large field of tall grass. The owner found the buried rocket easily due to the Chute Tamer™ control's siren. Two parts of that rocket were salvaged to be used again without repairs: the motor casing and the Chute Tamer™ control. Newer versions of the Chute Tamer™ control are made from an even stronger and flame retardant ABS material.
    3. Is it possible to design a Chute Tamer™ control that is based on a barometric (altitude) sensor? Anything is possible, but the barometric sensors that I am familiar with are fragile and will not survive the blast of the ejection charge. For this reason, barometric altimeters are located in a separate sealed electronics bay specially designed to protect the sensor from all black powder charges used in dual deployment recovery. The timer-based Chute Tamer™ control can be placed right into the body tube of single-deploy rockets allowing it to retrofit easily and without modification.
    4. Why is the cutter heating element disposable? The heating element's job is to reliably cut the fishing line and release the main parachute at the appropriate time. There is a trade-off between a heating element that can be used over and over and one that always gets hot enough to be reliable regardless of the temperature outside (at altitude) and for a reasonable range of battery strength. To ensure cutter reliability, the heating elements typically burn through when used.
    5. Does the cutter heating element ever last for more than one flight? Yes, the modular heating element may survive the heating process. You can verify the integrity of the modular heating element by putting it into the Chute Tamer™ control, turning it on and listening for the continuity tone (high-high tone that follows the timer's high-low self-check tone). If the continuity tone is present then the modular heating element is in tact and ready for another flight. If the timer in the Chute Tamer™ control goes silent at the end of its self check, then the modular heating element is melted through and should be discarded. Re-useable modular heating elements are an indication that the battery is approaching the end of its useful life. This is especially true in cold weather when more battery power is required to heat the modular heating element sufficiently.
    6. How long does a new 9V battery last? This depends on how long the typical launch sits on the launch pad in while turned on, or out in the field (siren on) before recovery. In general, the battery should last for several flights. Warm batteries provide more power than cold batteries. On very cold days, it is a good idea to keep the batteries for rocket electronics in your pocket white prepping the rocket.
    7. What kinds of batteries can be used? Only snap-connector style 9 volt batteries should be used. I have successfully test alkaline, NiCad, and lithium 9 volt batteries. Any of these should work well in the Chute Tamer™ control.
    8. Does one kind of battery work better? The main difference between alkaline, NiCad, and lithium 9 volt batteries is there weight. The heaviest and most inexpensive alkaline batteries weigh in between 46 and 47 grams. The lightest battery is the lithium at just over 33 grams (nearly one third lighter). Finally, the medium weight rechargeable NiCad battery weighs in at about 41 grams.
    9. I lost my lid screw, what kind of replacement screw do I need? Because the lid slides securely onto the body of the enclosure, the lid screw is only an added precaution. The lid screw is a Phillips flat head machine screw with a 4-40 thread and a 5/16 inch length (about 0.31 inches). The Chute Tamer™ control should not be flown without the enclosure lid slide completely into place.
    10. Is the PerfectFlite timer modified for use in the Chute Tamer™ control? The timer electronics in the Chute Tamer™ control are unmodified. This timer was selected for its superior quality, reliability, light weight, and small size. It is a PrefectFlite MT3G MiniTimer3 with an integrated G-switch. The PCB standoffs used to mount the timer are not the same dimensions as those sold with the timer.
  3. CT Operation:

    4. Chute Tamer(tm) connected to rocket
    1. How does the Chute Tamer™ control detect launch? The Chute Tamer™ control has an integrated G-switch that detects the acceleration associated with rocket engine ignition and launch. To prevent unwanted detection (false positive launch detection), the PerfectFlite timer has a built-in de-bounce algorithm. This algorithm requires that a minimum of 2 G's of acceleration must be detected for 0.5 seconds or longer.
    2. How tight should the nose cone be? When using the Chute Tamer™ control, the rocket's nose cone should pass the "shake test". The "shake test" involves turning the prepared rocket (CT and parachute loaded) upside-down and shaking it gently to see if the weight of the recovery devices will separate the nose cone. (The nose cone should remain attached during this test.) The reason that this is important is that during flight, when the thrust of the rocket engine suddenly stops and the rocket begins its long coasting deceleration to apogee, the contents of the rocket will push upwards into the nose cone. If the nose cone separates easily, then this upwards force will lift the nose cone off the body tube causing the rocket to separate prematurely. The added weight of the Chute Tamer™ control will increase this upward force on the nose cone at the point of engine burnout.
    3. Is the Chute Tamer™ control compatible with Aerotech Warp9 propellant? No. While I have not tested this combination, I know that Warp9 engines burn for only 0.25 seconds or so which is not enough time to trigger the G-switch/de-bounce mechanism integrated into the Chute Tamer™ control.
    4. What happens if the main parachute is not released? In the unlikely event that the main parachute is not released, the rocket will be tumbling (not ballistic) to the ground. Remember that the motor's ejection charge opened and de-stabilized the rocket at apogee. If a drogue parachute was used, then the rocket will come down under the drogue.
    5. What is the main cause of the main parachute not being released? The most likely cause of heating element failure is a bad battery. Please use a new battery or check it before flight.
    6. Can I use more than one Chute Tamer™ control in my rocket? Yes! The only limitation would be the added weight (4 ounces each with 9V battery). Using the 5-1 weight to average thrust safety guideline, each Chute Tamer™ control would add an additional 6.3 newtons of average thrust required for a safe launch. A two pound rocket with a 29mm motor mount requires over 50 average newtons for a safe launch (F52 engine). This same 2 pound rocket with the Chute Tamer™ control installed will require over 56 average newtons (F62 or G64 engine). For each additional Chute Tamer™ control used, an additional 6.3 newtons of average engine thrust is required for a safe launch.

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