Utilizing a Drogue and Main without dual-deploy for JrHPR

Hi, bit of a newb here. I'm working towards getting my Junior HPR certification here and I'm working on designing my certification rocket. As part of the regulations I'm not allowed to used a dual deployment system, but I still want to use a drogue/main pair so I don't have to walk miles to recover the rocket. My confusion comes as to how exactly I would go about assembling the recovery system. I'm currently thinking about using a 15" Fruity Chutes Drogue Chute and a 36" Fruity Chutes Elliptical Chute (both found on Apogee Components), with a Jolly Logic "Chute Release" to control the deployment of the main. (If this is wrong please let me know I'm completely new to using any parachutes other than a singular basic Estes chute.) From there I'm not exactly sure what to do. The description on the drogue's page says it can be used to help pull out the main, so does that mean it somehow attaches to the top of the main's canopy? If that's the case, I'm concerned it might end up pulling the main out of the Chute Release too early. Any help with this problem would be appreciated! Thanks!

Basic info on my current design: I'm using a 4" LOC body tube, I'm aiming for my rocket to weigh about 1300g (1600g if/when I ever want to put a payload on it), and both parachutes will be stored in the same tube, right underneath the payload shoulder, to be ejected at the motor's ejection charge.

I would recommend skipping the drogue as the main/chute release combo would serve the same purpose. The drogue doesn't slow the rocket down very much. One of the main purposes is to create separation between the upper and lower sections of the rocket. You don't want them banging into each other or for the chute to get tangled up in the booster.

How high are you going?

I'm with Zeus-cat in that I doubt that you're going to be going high enough for it to matter much. Something that size at 1300g with a typical H motor will probably get to 2,000' or so, with a small I you might get it to a bit over 3,000'. It's not going to drift for "miles", unless you launch in a windstorm. You might want to read up a bit more on the Chute Release, it sounds like you may not quite understand what it does... it simply binds the chute until you get to a certain altitude. You still need to use "something" to get the nose off and the bound chute out. Typically, "something" is the ejection charge in the motor.

@Zeus-cat , My rocket will be going up about 1600 feet on my cert flight according to OpenRocket, but I'd like to build in the capability to travel higher on larger motors afterwards. I'm a bit concerned about not using a drogue because my OpenRocket model shows that deployment will end up happening when the rocket is falling at nearly 70 ft/s, which seems like it would damage the chute (or airframe). When I put the drogue on the model, it halves that to about 35 ft/s, which still seems kinda fast but nowhere near as risky. Although since the Fruity Chutes are beefier than the chutes I'm used to, they might be able to hold up to a high-speed deploy, but I just don't know.

Chute release is the way to go

Fruity Chutes parachutes will easily handle main deployment at 70fps. I know this not only from personal experience, but because Gene Engelgau told me so himself. On my larger rockets I aim for a 75fps drogue descent rate. I doubt zippering will be a problem, especially if you a lot of shock cord and avoid using kevlar where it can rub against the opening of the body tube. If you want to use kevlar for it's heat resistance properties, you can use it as a harness that ends inside the body tube with a loop to which you can attach a more forgiving material.

Your chute release/parachute will provide some drag which Open Rocket is probably not figuring in. So your descent rate will be a little slower than 75 feet per second. If you think you need more drag you could go with a streamer or a small chute, but I don't think you will need it.

I just checked my Stratologger data for my 4 inch LOC Iris on its dual deploy flights. It descends at between 50 to 60 feet per second after apogee with a small drogue (not a chute release) and I have never had an issue with the main causing damage on opening. I use the drogue to keep the upper and lower sections separated, not to slow the rocket down.

I assume your shock cord is a strap that is about half an inch wide. That won't damage a LOC tube like the thin shock cords which can cut into an Estes rocket.

And when setting your chute release you need to consider that it can take a few seconds for your chute to fully open and slow down your rocket. I wouldn't set it to open below 500 feet until you know how the system works and how long it takes for your chute to open.

OK, thanks for your help!