Recover Electronically Signed Ordered with airSlate SignNow

Lots recover electronically signed

hi this is John this video is on electronics and the use for recovery in rockets a lot of people have trepidation about electronics I know when I first started out in rocketry I didn't use electronics for quite a while and in fact it wasn't until I was forced to by wanting to fly a hybrid so in order to dispel some of that trepidation I thought I would put together a video showing basics of how electronics work and how to use them I think in the end you'll find as I did that is actually easier and more reliable to use electronics and then you have the side effect of getting interesting data about your rocket flight anyway let's dive in I think a lot of the trepidation comes about because the parent complexity so but let's start with a relatively complex electronics Bay this comes from my solar sail or upscale it's a inside a 4-inch airframe it uses dual deployment and redundant electronics okay that sounds like a lot of stuff we'll break it down and go over in more detail but I'm just showing you that even relatively complicated it's not actually that much going on we have a power switch we have space for 9-volt batteries we have the to electronics units and then we have wires going to the ejection charge that's really all there is to it okay let's go back to model rocket engines and see how recovery got started it's important to review this because this is how the terminology and methods of measurement came about so let's start with the model rocket thrust phase the propellant burns in an end burning configuration producing thrust and lifting the rocket this is what propels the rocket upward during this time the propellant grain burns from the aft forward then once the propellant it burns out the delay grain starts to burn this is why delays are usually measured from motor burnout rather than from liftoff which would make more sense then after the delay grain burns the flame reaches the black powder charge exploding forward and ejecting the recovery system and really things aren't that different when you move to high-power motors using motor ejection we still have the main grains producing the thrust a delay grain producing a delay and then a black powder ejection charge at the forward end providing the ejection force one significant difference to be aware of is most high-power motors use bates grains in which case instead of burning from the end it burns from the inside what this means is that the combustion chamber is not only from the aft and burning forward but all along the inside burning outwards so while we still count the delay from motor burnout the delay charge actually starts burning at liftoff unlike a model rocket engine okay so what does that mean for model rockets the engine in the apt relatively short contains bearing up or recovery and we only brake at the nose to eject the parachute for mid power rockets similarly we have more or less the same shape just larger the motor can pressurize this area popping the nose pound and opening for recovery so this basic arrangement of the motor works reasonably well the other big thing with model rockets and to a lesser extent mid power rockets is that they're not all that heavy so the ejection charge is a little early or a little late they can kind of compensate however with high power rockets heavy components more mass inaccuracies in the ejection can cause quite a problem so let's think about what happens during flight the rocket lifts up accelerating under thrust motor Vernell it starts to decelerate at some point drag and gravity cause it to slow down and it reaches what we call a Apogee here ideally you would eject opening the rocket letting the parachute come out and having you drift down safely however if your ejection is too early or too late relative to the stationary Apogee point they're going to be forces acting on the rocket that are greater depending on the velocity at which it's moving and the mass of the part now one thing that happens with late or early ejection on heavier rocket to something called a zipper what happens with a zipper is the Rockets still moving let's say the ejection is early the rocket is still moving ejection happens the parachute comes out you get forced sideways pulling this can zipper or tear a hole down the side of the rocket and this could happen whether the ejection is early or late so it's really important to get an injection as close to a fancy as possible when you start having many motors in the abdomen and large heavy nose cones and payload bays in the forward part of the rocket it becomes really critical to eject at Apogee because the forces operating are much much greater this is where the more precision that you get from electronic deployment becomes critical that's not even counting for a dual deployment or other more advanced technique another big benefit of electronics as it gives you a wider choice of recovery arrangements so for comparison we start with motor ejection where the recovery impetus comes from a motor and pushes everything out forward the simplest use of electronics is to place them in the nose this has the advantage that be used with a rocket that wasn't set up for electronic ejection I've put together a video on adding an electronics Bay into a standard plastic nose cone for more information with this sort of arrangement the ejection charge fires from the nose cone but basically recovery follows the same pattern another common arrangement is to add an electronics Bay this is a dedicated section of the rocket for the electronics this isn't much different from the previous method except we have more space in a dedicated area for the electronics finally for a rocket that had electronic dual deployment in mind during the design we have this arrangement here the rocket breaks in two places one at the drogue and one for the main at Apogee the rocket breaks aft of the electronics Bay just before the booster into two sections the rocket sections will come down on a drogue parachute relatively more quickly than the main parachute then once the rocket descends to a set altitude such as 1,000 feet the large main parachute comes out forward of the electronics Bay and brings the rocket down gently to a final landing so clearly dual deployment with backwards ejection booster arrangement is my favorite method of recovery here you can see a nice shot of my lock Magnum descending when flown in 2000 as well as a quick diagram showing how I modified the stock arrangement to a dual deployment arrangement I basically arranged every rocket this way and you can find many examples of this on my website and addition of course electronics give you the ability to do more things than you can with just motor rejections first and most obvious you get accurate altitude even the simplest units will report the maximum altitude achieved and the more complex sometimes called recording units will record pressure and acceleration all through the flight and be able to give you more information like acceleration and velocity in addition you can use electronics for staging delayed out wards and other effects that you can't achieve with motor ejection or would be prohibitively difficult ok let's look at some electronics there are many manufacturers people making very simple units that only record peak altitude to ones making full flight computers that have many output functions and complex behavior two of my favorite fall somewhere in the spectrum although a little bit more towards the flight computer side this is the g-wiz LC x one of the later products in the long line of g-wiz and this is the Argos tiny made by abd electronics the g-wiz is fairly typical in having a terminal block to which the battery one or two different batteries and three outputs one output fires at lunch another output fires at Apogee and another output fires at the low altitude set point the are des uses a wiring harness and supports four outputs the first two outputs are Apogee and low altitude but there's two additional outputs that can be set to many different combinations based on liftoff burnout Apogee low altitude set points plus time delay so this is very flexible unit okay so let's talk about what you connect your altimeter obviously you have to supply it with power the most common is probably a standard 9-volt battery but many people are moving to lithium polymer batteries you can either use a two cell or a three cell depending on the voltage requirements this provides a lot more current in a very small package you don't want to arm your electronics until the rocket is on the pad and ready to launch so that requires some method of switching units usually the switch is put in line with the battery and power is fed to the electronics only when the rocket is upright on the pad the simplest method for implementing a switch is to have the two wires sticking out of the airframe and to twist them together and tape them to the outside next method involves a switch of some sort I've had good luck with simple slide switches other people like the screw switches and the most highly recommended switches are probably the searcher voltage selector switches whatever you use make sure it's a switch that solidly locks in the on and off position so vibration or impact of landing won't turn it off your power possibly switched provides the necessary electricity to run the unit but the unit also has outputs and these are used for events since we're focused on recovery the events we're going to talk about our apogee and low altitude ejection charges I have here an electric match this is a debut fire twenty eight B but there are several different manufacturers available the this is connected to an appropriate output and when the electronics wants to fire that output current is applied to the electric match which will cause the head to pop in a small explosion now that's not enough to do much but what we'll do is we'll make an ejection charge by wrapping black powder around that match head to provide enough force to open the rocket and eject the recovery system generally your electronics Bay will have a plate on which everything's mounted the electronics units themselves are mounted on the plate usually with standoffs the switch if you use it should be firmly mounted as well and accessible from the outside batteries should also be mounted firmly and in some ways these are the most tricky one natural thing that people jump to is mounting the batteries using battery holders the problem is I think this is actually a mistake and I don't use battery holders in my opinion having the connectors to the battery mounted firmly to the plate and having the battery separate isn't cause for failure some to some extent during acceleration but to a greater extent during the jarring of events and landing you're gonna have the battery holder with its connectors held solidly and the mass in the battery moving slightly so that's gonna provide an opportunity for disconnection I just skip all that use the normal 9-volt battery connectors and dismount the battery using plastic zip ties so here's the battery connected with cross zip ties these things are very strong and the battery is not going to break through them and if it does shift a little the connector will ship with it and there's no chance of losing power to the electronics there's no reason to use a battery holder this is simpler safer and more effective than any battery holder now of course your electronics unit and its LED have to fit within the rocket and they have to fit in an area that is physically separated from the recovery area not only do we want to protect the altimeter from the high pressure of the ejection even more important we want to protect the electronics from the corrosive black powder residue so we want a seal as much as possible the electronics Bay from the recovery area the other thing we want to do is make our electronics easy to take out and prep outside the rocket and then insert here the coupler between two sections of the rocket is actually the container for the electronics here I can access the switch from the outside and there are four holes around the perimeter for retaining the bay the aft end of the bay is where the output will go for the drogue the forward end of the bay is the output for the main the bay itself slides in with a section of coupler to provide more area to provide a seal but yet the whole bay can be removed for prepping it's very important to make it easy to prep especially when you're out in the field and conditions are not ideal now the most common way to provide the four of the ejection charge is with black-powder you pack a small amount of black powder around the electric mass head and when the match head fires it creates a small explosion that ignites the black powder so black powder works best when it's tightly contained but for our purposes at least the purposes of rockets flying below twenty-five thirty thousand feet the containment isn't all that critical if you're flying at higher altitudes you'll need to take additional precautions but we won't cover that here so you need to install the electric match in a container where the powder is packed around it and can't move a common method is to use small plastic vials which I'll demonstrate here now these you can prepare in advance take your electric match cut it to the length that you need then take your charge cap Cup drill a hole bottom pass your electric math wire most of the way through you can either leave this cap on or take it off I'm going to take it off for demonstration purposes to make it easier to see what's going on the other thing I like to do is mix up a little five-minute epoxy to secure this in the bottom and make sure there's no hole where the black powder grains can leak out so after you've threaded your electric match through most of the way put a little five-minute epoxy just below the match head this way when we pull the wire through a seal will be created around the hole that we drilled pull it to the bottom and set this aside to cure now how much black powder do you need for an injection charge of course that varies based on the volume that needs to be pressurized Google online for black powder calculator and you'll find very many online tools what I would recommend is take the amount that they specify back it off by 15 or 20% and try that by statically ground testing your charge and make sure you have a satisfactory recovery you can work up to larger amounts but there's no reason to start with a huge charge at the beginning but do be sure to brown test anyway once we've determined the amount of black powder we need we're gonna measure it out you can measure by weight or by volume most people measure by weight I do have this little scoop that's about a gram if bull we're going to measure about 2 grams and then we can pour that into our charge tub one of the nice things about the charge cups is you can make them up ahead and use different amounts once we fill the charge up tap thoroughly to make sure your black powder settles all around the EMAP and into the bottom once the amount of black powder that you want is in we want to maintain it in tight contact with the email and providing a relatively compact mask so I'd like to fill up the rest of the charge cap with Estes recovery wadding but you can use whatever works well for you some people would put in a paper desk tamp it down then fill with epoxy I think this is a little easier and faster so we'll fill up the gap make sure it's nice and tight and then close the bottle now we have our charge ready to go now as an aside I want to point out that black-powder ejection charges are not the only option if you're flying to higher altitudes or just if you prefer less issues with the black powder residue you can also use co2 based recovery systems the bay that we've been looking at actually uses the tinder Peregrine system of co2 recovery so the co2 cylinder along with some other parts would be stored in here installed at the top of the bay the ejection charge would fire a small very small black powder charge from the bottom forcing the cylinder forward and releasing the gas in that way we have co2 gas ejecting into the recovery area pressurizing it instead of black powder now electric matches have a characteristic resistance for Davy fire this is 1.2 ohms we want to make sure that the electric match is good both after we take it out of the box and right before we installed in our rocket so to do that we make sure that the resistance is in line now one note about electric matches they use solid wire not stranded so when we strip it we want to use a proper wire stripper not diagonal cutters diagonal cutters can nip the solid wire making the weak point which can break so always use wire strippers and we measure the resistance making sure between 1 & 2 ohms now either in advance or out at the field we're ready to install our ejection charge onto the outside of the bag we need to run the wire through a hole in the day but still preserve as much of the seal as possible to do that I like to use this tack and a bit of tape run your wire through and place the charge where you would like I like to flatten the wire a bit against the bulkhead take a small piece of poster tack and pack it around to seal then you can get a little tape to cover this and kind of hold the charge in place again it's easier the more you can design your Bay for prepping outside the rocket there's two reasons for this one is it's difficult to reach inside and work in the tube and the other is you can collect your Bay at home and then just bring it out to the field and fly so there you have some basic recovery techniques and in particular some tips for electronics now I've mentioned a lot of products and I've shown you my favorite techniques however there are many electronic units on the market and people have come up with very many interesting techniques for making waves propping them and of course there are many different brands of electronics so be sure to check out your favorite rocketry web forum and talk to the people at the launch site for more experienced and get the ideas that they have and what works for them in particular and urge you to talk to people where you launch at your rocket club and see what they're using that way you'll be using the same sort of units and techniques that they use and they'll be most able to help you of course with anything it looks more complex at the beginning but once you get used to it you'll realize it makes sense and it's not too bad anyway I hope this video is giving you enough confidence to try electronics yourself