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Different parts of mid power rocket recovery systems.
The way that you recover mid power rockets is almost the exact same as recovering small model rockets. The rocket is attached to a parachute that lowers it down from it's apogee and the shock cord keeps the nose cone and body tube together. However, in mid power rocketry there are a few more things you need and some other ways to deploy the parachute.
Let's start with the extra things you need or what you might want to upgrade.
1. The Parachute
Most low power rockets and many Estes Pro Series rockets come with plastic parachutes. These are fine for smaller rockets, but as you get into larger mid power rockets you want a nicer parachute that holds up to the increased size of the ejection charge as motors get bigger. The parachute also needs to handle the typically larger and heavier rocket. Some parachutes that I would recommend for larger rockets are Loc Precision nylon parachutes or if you have a bigger budget, Fruity Chutes classic or iris parachutes. I only recommend the Fruity Chutes for rockets that you really want to get back due to the parachute's expensive price. Iris parachutes have a flattened donut shape and tend to create more drag. Since some of the mid power rockets are more expensive I would prioritize one of these upgrades to make sure you get it back. Only upgrade if your kit does not come with a high quality nylon parachute. You can also determine what the optimal size is of your parachute should be is by using the Descent Rate Calculator (optimal descent rate is 15 fps). One parachute that I do not recommend is Apogee's parachutes. They tend to be brittle to heat and can be burnt closed even with lots of protection which means the parachute can't open.
2. Fireproof Nomex Blanket
This is something that I would also recommend you buy for your mid power rockets. Most kits do not come with one of these. This is used in place of recovery wadding to protect your parachute. Although you can still put in some recovery wadding as a backup. This wraps around the parachute and protects it from the ejection charge. It can easily separate from the parachute and allow it to inflate once it is out of the body tube. Here is a video from Apogee which shows you how to use one.
3. Kevlar or Durable Nylon Shock Cord
Some mid power kits, especially from Estes use rubber or elastic shock cords! These are not as resistant to the heat of an ejection charge and can become brittle easily. This is why I recommend that you upgrade this if your kit comes with an rubber or elastic shock cords. Kevlar heat resistant and I have never seen one burn through. Nylon shock cords are still pretty strong but not as strong as kevlar ones but nylon is usually cheaper. The only bad thing is that thin kevlar shock cords can cause zippering on cardboard tubes but that shouldn't be a problem if your parachute is deployed at low speeds. Zippering is where your shock cord rips the body tube of your rocket if the recovery is deployed at high speeds. You want to have double or triple the rocket's length in shock cord.
Those are the 3 upgrades that I would recommend you make to your mid power rockets if the kits do not have any of those already. There are some differences in which the recovery system is laid out in most mid power rockets which I will cover.
Instead of gluing the shock cord to the inside of the body tube like most Estes kits in mid power rockets, the shock cord is attached to the end of the motor mount on an eye bolt or a u-bolt. This is a positive change and gives the shock cord a stronger anchoring point. You also use a lot of quick links to in order to connect certain parts of the recovery system to eye and u-bolts. Here is a recovery system of a single deploy mid power rocket.
Finally, there are few things that some mid power rockets have that you should know about. Some mid power rockets have a Jolly Logic Chute release. This is used to control when the parachute is able to fully inflate. This is useful for higher flying rockets in order to manage drift.
Some mid power rockets have electronics bays in them which are stored in the couple of a rocket. These typically house dual deploy altimeters in order to record data about the flight or to perform dual deploy. This is where a small drogue chute is deployed at apogee in order to minimize drift before deploying the larger main parachute. Below is a diagram showing this.
I hope I cleared up some of your questions or concerns about mid power recovery systems. May your skies be blue!