Hi everyone!

[casper1a]

Hello, Forum! I am originally from Eastern Europe, where I developed a huge passion for rocketry, but due to very limited ability to be exposed to physical stuff, I was mainly focused on coding. Now that I attend a college in the states, I have joined my rocketry club.

And of course, I was assigned a task to create a rocket that reaches 10,000ft and breaks the sound barrier as an introductory project (How awesome!). Oh, and carry 120g of payload too. I think I settled on a rocket motor Cesaroni L1720, and 3in 4ft fiberglass as my body tube. I have done some 1d sims which look good, and now I have translated that into a very rough openrocket sketch and it looks good. I also need a dual-deployment recovery system, which I genuinely have no clue how to handle. I will attach a screenshot on what I have so far, and would be really grateful to receive any feedback, whether I am on the right track, what resources to use for my payload bay design etc.

Thanks everyone!

 

[smstachwick]

Welcome!

The common approach for dual deployment is to use a coupler and mount the electronics on a sled within. The lower portion of the airframe houses the motor mount, fins, and drogue chute, which is separated through a black powder charge activated by the electronics at apogee (all motors Type L and larger, some smaller ones, or when the modeler prefers it), or with the motor’s built-in ejection charge (most motors Type K and smaller).

The main is housed in the upper portion of the rocket and is deployed by the electronics at low altitude. Some people prefer to have redundant charges and even fully redundant deployment systems.

You can find flight computer kits by Eggtimer that you can solder together, but there are a bunch of units available from other manufacturers.



Side questions: what are you thinking for initial guidance? 1515 rail? I don’t see any buttons or rail guides on your screenshot. Can you post the .ork file?

 

[Hobie1dog]

 

[jkovac]

Hello, Forum! I am originally from Eastern Europe, where I developed a huge passion for rocketry, but due to very limited ability to be exposed to physical stuff, I was mainly focused on coding. Now that I attend a college in the states, I have joined my rocketry club.

And of course, I was assigned a task to create a rocket that reaches 10,000ft and breaks the sound barrier as an introductory project (How awesome!). Oh, and carry 120g of payload too. I think I settled on a rocket motor Cesaroni L1720, and 3in 4ft fiberglass as my body tube.

What led you to pick an L1720? Does your school already have one on hand? If not, it might be hard to find one currently. Also, you might want to reconsider a minimum diameter rocket (motor just fits in body tube, no motor mount) if you don’t have much previous rocketry experience.

 

[teepot]

Welcome to the Forum.

 

[cwbullet]

welcome

 

[casper1a]

What led you to pick an L1720? Does your school already have one on hand? If not, it might be hard to find one currently. Also, you might want to reconsider a minimum diameter rocket (motor just fits in body tube, no motor mount) if you don’t have much previous rocketry experience.

I think we have some in our school I could use. It will be a minimum diameter rocket, as the motor is 3in, just as the body tube.

 

[casper1a]

Welcome!

The common approach for dual deployment is to use a coupler and mount the electronics on a sled within. The lower portion of the airframe houses the motor mount, fins, and drogue chute, which is separated through a black powder charge activated by the electronics at apogee (all motors Type L and larger, some smaller ones, or when the modeler prefers it), or with the motor’s built-in ejection charge (most motors Type K and smaller).

The main is housed in the upper portion of the rocket and is deployed by the electronics at low altitude. Some people prefer to have redundant charges and even fully redundant deployment systems.

You can find flight computer kits by Eggtimer that you can solder together, but there are a bunch of units available from other manufacturers.

View attachment 627730

Side questions: what are you thinking for initial guidance? 1515 rail? I don’t see any buttons or rail guides on your screenshot. Can you post the .ork file?

They told me not to worry about the guidance rail for now, we already have one built but I dont know what exactly. Still, thank you for the useful schematic and information!

 

[smstachwick]

They told me not to worry about the guidance rail for now, we already have one built but I dont know what exactly. Still, thank you for the useful schematic and information!

Ok.

Here’s another thing to consider: Center of Pressure can move around due to compression effects at transonic and supersonic speeds. What does your stability look like at, say Mach 0.8? Mach 1? Mach 2? You don’t want this thing turning cartwheels right at burnout.

 

[jkovac]

I think we have some in our school I could use. It will be a minimum diameter rocket, as the motor is 3in, just as the body tube.

Does your rocket club at your school have a website? That would help us in knowing what kind of support you already have.

 

[casper1a]

Ok.

Here’s another thing to consider: Center of Pressure can move around due to compression effects at transonic and supersonic speeds. What does your stability look like at, say Mach 0.8? Mach 1? Mach 2? You don’t want this thing turning cartwheels right at burnout.

My center of gravity and center of pressure relation (Stability in open rocket) is around 1.5 and 2 for now, which I was told is good. Now, I read a bunch about payload and avionics bays, and will send something here and would be grateful if someone is to check it out and let me know what I did right and wrong.

 

[smstachwick]

My center of gravity and center of pressure relation (Stability in open rocket) is around 1.5 and 2 for now, which I was told is good. Now, I read a bunch about payload and avionics bays, and will send something here and would be grateful if someone is to check it out and let me know what I did right and wrong.

Post an .ork file and I’d be glad to take a look. Here is fine but a direct message also works.