(Part 2) Best products from r/rocketry

Ham radio associations like the ARRL probably have the best repository for beginners. A lot of the ham exam study guides and videos have good information for those wanting to learn about RF. I picked up some amateur radio books from the 60s at a local library book sale and they proved to be quite valuable guides.

Also, and I can't recommend this enough, pick up an RTL-SDR. For less than $30 and the cost of a diy antenna you can listen to literally anything from the LF to UHF range. Satellites? Old fucks on 2m? Air traffic? Garage door openers? ADS-B? You name it, SDR can do it.

This is also much easier and cheaper to do than most people realize.

• Amateur Radio License. Fee is about $5-$15, depending on club administering the test, I got mine after about 5 hours of studying. There's a ton of free online resources, or fairly cheap online tools.
  
• Transmitter. Big Red Bee is $60
  
• Transceiver. Baofang sells one on Amazon for $28
  
• Build a yagi antenna for around $20
  
  All in, you're looking at well under $150 for something that will work really well, last a long time, and will give you a license into another potential hobby.

You can make usable parachutes for low power rockets out of nothing more than tape, dental floss, and trash bags. Mylar blankets work even better than trash bags, and pack just as small or smaller. At slightly larger scales you'll want to move to ripstop nylon for the canopy material. You can purchase ripstop at many fabric stores. It comes in ~60" wide rolls, and you can buy it for around $6 per yard (i.e. 1 yard by 60", NOT 1 square yard). You can find it for cheaper than that online, but unless you're buying half a dozen yards or so, shipping makes it more expensive than buying at a store. You will need to sew the shroud lines onto ripstop, tape is insufficient. If you sew together multiple "gores," you can greatly increase the efficiency of the chute.

That being said, the most economical way to get started is to buy a cheap estes launch set. This will come with a rocket, a launch pad, and an electronic launcher. The rocket will include everything needed, including a parachute. You may have to purchase motors separately. Here's a launch set on amazon for less than $20.

Apogee sells a camera and little vacu-formed shrouds for it and they have a video.

I've used a lot of the 808 #16 cameras - if speeds aren't too high, you can just tape them on and make a nice tape shroud. If you are really worried, a long zip tie around the camera body makes a place to attach a tiny zip tie through the key ring loop of the 808.

I also just bought a RunCam 2 because a friend makes awesome rockets videos with his. It's going on a big heavy rocket, so the larger size isn't a terrible thing.

Think about stability, the camera moves both the CP and the CG.

I do not think there is water involved; yes it is a "water bottle" but it is a gas inside.

There is nothing inherently special about mach diamonds. It is simply a discontinuity in gas properties. There's a few things at play here:

• Schlieren optics
  
• Pressurized gas
  
  Gas Dynamics
  
  While, yes, you should not be able to accelerate past the sonic condition for the gases entering the converging section of the nozzle; what is stopping the gas from existing at conditions "Mach > 1" relative to the sonic condition of the ambient gases? (This becomes important in reacting flow such as rocket nozzles where the sonic condition of the exhaust products is not the sonic condition of ambient gases).
  
  Shock diamonds will exist when there is a discontinuity in the gas conditions. See: Gas Dynamics References or any book like Gas Dynamics vol. 1 (Zucrow Hoffman) / Fundamentals of Aerodynamics (Anderson). In order to go from the exhaust gas properties to ambient conditions there must be some interface; under certain conditions (M>1) a shock will exist that allows the two states to exist in proximity. For states where (M<1) there is a gradual change between the two conditions dictated by your gas dynamic equations (Navier-Stokes).
  
  Schlieren
  
  Now that we understand why a shock exists; what does Schlieren add? Schlieren optical techniques allow you to see the changes in the refractive index; in the case of gaseous media this translates to density gradients (first derivative), and shadowgraphy lets you see second derivatives. Schlieren & Shadowgraph Techniques (Settles). If you accept that changes in density are related to refractive index, then you can see how Schlieren optical techniques can enhance the viewing of shocks (strong density gradients -- see shock tables and density ratio across a shock). Schlieren techniques can be tuned to REALLY enhance even small density gradients (non-shock environments such as a match, or convective currents around your head -- See Settle's books for good images).
  
  
  

Buy a swagelok valve from here (paying full price is for suckers and these guys ship faster than Swagelok anyways). For reference you can get a brand new swagelok for less than $40 from this site. Just compare the part number to the swagelok website to check seal/o ring materials.

Buy a high torque stepper motor and hook it up to the valve. You will also need a stepper motor driver that can deliver sufficient amperage. This is pretty much the simplest/cheapest way to get 150 in-lbs of torque delivered to the valve. Theoretically you'd only need about 50 but better safe than sorry.

This is the cheapest and simplest way to get what you want. If you already have gear for pneumatic control (air tank, solenoids, regulator, etc) pneumatic might be cheaper but you also don't get fine position control with pneumatic so take that as you will.

Yeah, that's definitely a good experiment to perform. If you need any assistance setting it up, just let me know. Also, something I forgot to mention is that you also need an Hx711 amplifier (get it from here). This is used for amplifying the signal from the load cell to a signal that the Arduino can read.

From a "how do you build it" point of view, this is a great book:

https://www.amazon.com/Make-Rockets-Down-Earth-Science/dp/1457182920/ref=mp_s_a_1_1_sspa?keywords=make%3A+rockets&qid=1570893860&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyQ1pORFY3TzM2UFc0JmVuY3J5cHRlZElkPUEwODQ4ODIxMTdFVFExN1U0UjBNRSZlbmNyeXB0ZWRBZElkPUEwNzE2ODg5OE9UTTY4NktBRlZWJndpZGdldE5hbWU9c3BfcGhvbmVfc2VhcmNoX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Should you get into high power Rocketry, there's a similar book for high power.

It's a fantastic hobby. I've been launching smaller rockets since I was 10 or so (dad was an engineer, and I've become one as well). Start out small, take your time, learn as you go...it's good stuff.

A little late on this one. But Von Braun: Dreamer of Space, Engineer of War was a solid read.

Edit: Also, if you are interested in more space race stuff, this book is one of my favorites, Red Moon Rising: Sputnik and the Hidden Rivalries that Ignited the Space Age

I just looked at this for a 29mm Cesaroni motor. I'm going to switch over to a 29mm motor mount. I think I'll just use a 29mm one grain F load instead of adapting to 24mm. I'll definitely try that in OpenRocket! I would never use balsa for fins :^ ) You caught me. The 1/8" 1sq ft G10 stock is a bit pricey at $27.00 per unit, so I think I'll go for this if that sounds good.

I would strongly recommend the Este's Atomic Sky kit, its almost ready to fly and snap together. All you need is a pack of motors, some parachute wadding, and batteries.

https://www.amazon.com/Estes-Atomic-Sky-Launch-Set/dp/B00DRKCKGW

this one, just because I am on a tight budget, and buying everything separately was expensive. Like I said, I am getting a larger one pretty soon.

Drill a hole in the base of the nose cone next to the attachment point and drizzle in epoxy to whatever weight you need. For bonus points, use a hobby syringe and your hole can be tiny (~1mm).

Estes Executioner.

Camera on amazon

Although if anyone knows of one with similar weight yet better picture please let me know!

I was just a volunteer at the launch site. I did see the camera they used, but am not sure what it was. It looked very similar to this one: https://www.amazon.com/Insta360-Camera-Sports-Action-Photos/dp/B074VW233J/
They basically had like a 6" part of the body tube of plexiglass so the camera could video all directions. The launch was a total success - good start, chute deploy, recovery w/ no damage. I am so happy for them.

Its actually a modified Custom Liberty with a Estes Loadstar II upper section/nosecone. Fly's great!

Here is a pattern you can cut out of index cardstock/heavy paper and build for no more than $1-2 in supplies at a local craft store (or which you may already have, or can borrow), plus instructions:

Mignight Express

You'll still need a launcher, and that could be a significant expense (relative to your $30 budget).

 

All told, you're probably better off getting this https://www.amazon.ca/Estes-1427-Flying-without-Engines/dp/B003CT4B0G/ which includes everything but the engine for $33 (find something for $2 to get free shipping if you don't have Amazon Prime).