This video shows you how recovery works, various arrangements from motor ejection through electronic dual deployment, and my favorite products and techniques. See jcrocket.com/electronic-recove... for more info.
Hey John, thanks for the video. Your content always helps when I'm building and stuck. My biggest problem is finding a safe place to launch in Arizona! Clear skies and happy Landing brother
I've lost a couple cheap rockets as a kid ...now as an adult wanting to go mid/high power the rockets are no longer cheap so every rocket I've built has dual-deployment ...very informative video and your method is how I was taught ...not to mention with dual-deployment unless the wind is really high speed you generally don't have to walk as far for recovery
Thanks a lot for your videos. I have been exploring your channel for a while and you have great content to help beginners in high-power rocketry. Even more seasoned rocketeers may find valuable pieces of advice from you.
John, the Rabbi is in several episodes....gotta check em out. And, yes it was a compliment. Your video was great, and informative as I ponder the next steps in my rocket recovery systems.
Great video! For my Ejection Charges, I am going to take a 1 inch by 1/2 inch diameter copper pipe, sweat on an end cap, and screw it to the bulkhead via a small hole and screw in the end cap. I will have thumb screw connectors on the bulkhead that the electric match attaches, I stick the match inside the copper pipe (pot), tamp in the black powder, a little wadding, and a few drops of hot wax to seal it. I am going to have two switches, one for Main Power, and another for Launch/Eject Safety. I prep the rocket on the stand. Place my electromagnetic Launch Transducer on the proper spot of the hull on the Avionics Pod (no mechanical connection), the Launch Panel is over 100 feet away, I have the key so it is safe. I use wire not radio to launch - less chance of jaming/false triggering. I turn on the Main Power on the rocket, the Trinket M0 does its self test and if all is OK and it confirms no current to the Launch/Eject transistors, a greed LED comes on (safe to apply power via the Launch/Eject Safety switch). If the green LED is not on, something is wrong and you simply turn off the main power and leave the safety switch in the safe position. I walk back to the Launch Panel, put in the key and turn it to Power On, I can see the green LED on the rocket. If still green, I press the launch button, this causes a strong magnetic field in the Launch Transducer. The circuitry inside senses the field and begins its "mission" sequence to launch and control ejection at apogee.
Very interesting, can you give more detail on how reverse ejection works, the arrangement of the parachute and such ? I never thought of that as possible method before.
"Reverse" just means which part of the airframe the coupler is fixed to (aft vs forward section). Expanding gasses press evenly on all surfaces of the container so it doesn't really make any difference which end the coupler slides out of. The parachutes are still arranged the same way.
John, just wondering why you choose to use the plastic vials instead of ubiquitous cups that you tend to see for deployment charges. It seems obvious that they are lighter, less expensive and simpler. Are there any other reasons? Any other advantages or disadvantages to your method? Also, regarding retaining the vials, have you considered a lightweight electrical clamp to hold them down, or would that affect the deployment charge in a negative way? I only ask because I know things like heat can affect the adhesive on tape and I'm a little leery of the affect of a vial-style deployment charge coming unstuck after sitting on a hot pad and swinging free.
The charge wells are fine; I just find it easier to use disposable containers. They're easier to prepare outside the rocket and there's no need to clean the wells. They charges are light, so I don't think there's any need to tie them down at all; I like to tape them in place just to keep things neat when prepping the rocket.
Hi John. I am looking for a cheap GPS tracker for my Level 2 rocket. I am planning to incorporate dual deployment, since I lost my rocket during previous L2 attempt. What would you recommend? Thanks.
I wrote an article on GPS trackers: jcrocket.com/gps-tracking.shtml Not sure any of them count as "cheap," though. If you can solder SMT parts, you can try this kit: eggtimerrocketry.com/home/eggfinder-gps-tracking-system/
How reliable is electronic deployment and is the software generally pretty easy to work with? I'm in the process of building a Madcow Super DX3 for my level 1 certification, and I want to put dual recovery in it, so that I can use it for my level 2 cert as well. Also, what is your opinion of the Perfectflite Stratologger altimeter CF? What kind of transmitter can I add to it so that I can get the location of my rocket transmitted to me? What will receive that transmision? Thanks you for your help -Matthew
If you do everything properly, very reliable. IMO the source of unreliability is not the hardware itself, but setup and wiring. For example, improperly stripping insulation on solid core wires will nick them, which creates a weak spot that can break. Note that electronics are also more accurate than motor ejection, which becomes a significant source of failure for heavier rockets. Most software used to configure electronics is poor, so I suggest starting out with a unit that needs little or no configuration.
Lightweight cloth is used in R/C aircraft, so a local hobby shop would have it (if there is one near you). Otherwise online; search for Hobbico 3/4oz cloth (www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXL491&P=ML).
I haven't done any balloons. I suppose you could put no charge on the drogue event and a normal parachute on the main, which would come out when the device was near the ground.
Since Hogden, the last US producer of black powder (Goex) will not be producing Goex after this year (2021), how does Pyrodex work for the ejection charges? I would think that the electric match would set it off ok. Pryrodex requires a hotter ignition source than real black powder.
I am going to use an Adafruit Trinket M0 microcontroller. It costs only $9 USD and is the size of a postage stamp. Adafruit makes a wide assortment of low cost sensors: Altimeter, 3 Axis Accelerometer, Temperature/Humidity, Cameras, and much more. Coding the Trinket M0 is easy, it uses Circuit Python built in. You simply write your code in a text file using any text editor (like Notepad), connect the Trinket M0 to your PC via a USB cable, the Trinket M0 shows up as a mini Thumb Drive and you simply drag and drop your file onto the Trinket M0 and you are good to go. It has a built in green power LED, a programmable Multi-Color LED, and a programmable on/off Red LED - all built in. It has 5 I/O pins that can be programmed as inputs or outputs, one can be used as an Analog input or output. You can daisy chain all of your sensors using just two pins programmed as an I2C bus. I am going to add model rocketry to the Summer STEM class I teach. Young minds love to program! Adafruit even makes the Feather M0 which has much more I/O and capabilities for only $22 USD and is only about double the size.
@@JohnLCokerThanks. I just finished the hardware design yesterday. Now I have to write the code. I had to switch to the Adafruit Feather M0 because I needed more I/O. Part of the power on self test is to measure battery voltage, then apply a small amount of current to each electric match as a continuity test to insure they are connected properly.
