Seeking Advice on L1 Cert Rocket

[Luke Madgett]

Hello, I am just starting out with rocketry and am working on designing a H motor powered rocket for my Level 1 Certification. I have had some help from a friend getting started in OpenRocket and have made an initial design. The specs are as follows: 3.9" diameter body, Cesaroni 269H110-14A motor, a Stability of 1.73, a mass of 1462g (with motor), and a 36" parachute.
Simulation data from OpenRocket is as follows: Velocity off rod - 11.5m/s, Apogee - 590m, Velocity at deployment - 3.11m/s, max velocity - 137m/s, max acceleration - 72.8m/s^2, time to apogee 10.5s, flight time 103s, and a ground hit velocity of 6.31m/s.

I have attached a screenshot of the OpenRocket design page, so you can see the overall shape of the rocket as well as the parts used. I would really appreciate any advice / tips that you could give to help out a 15 year old who really wants to get into rocketry!

 

[bad_idea]

Simulation data from OpenRocket is as follows: Velocity off rod - 11.5m/s, Apogee - 590m, Velocity at deployment - 3.11m/s, max velocity - 137m/s, max acceleration - 72.8m/s^2, time to apogee 10.5s, flight time 103s, and a ground hit velocity of 6.31m/s.

Velocity off rod is low. If you've not already done so, update the sim to use the actual rod or rail travel distance. Select the simulation -> Edit simulation -> Lauch rod -> Length. If you have already done that and are getting 11.5m/s, I'd look into motors with higher initial thrust.

 

[boatgeek]

Hello, I am just starting out with rocketry and am working on designing a H motor powered rocket for my Level 1 Certification. I have had some help from a friend getting started in OpenRocket and have made an initial design. The specs are as follows: 3.9" diameter body, Cesaroni 269H110-14A motor, a Stability of 1.73, a mass of 1462g (with motor), and a 36" parachute.
Simulation data from OpenRocket is as follows: Velocity off rod - 11.5m/s, Apogee - 590m, Velocity at deployment - 3.11m/s, max velocity - 137m/s, max acceleration - 72.8m/s^2, time to apogee 10.5s, flight time 103s, and a ground hit velocity of 6.31m/s.

I have attached a screenshot of the OpenRocket design page, so you can see the overall shape of the rocket as well as the parts used. I would really appreciate any advice / tips that you could give to help out a 15 year old who really wants to get into rocketry!

Other than the speed of the rail already mentioned, this looks like an entirely reasonable design. A few comments:

• The CTI H110 may be hard to find, and their 38mm motors are having reliability issues (I had two Jr L1s that I was mentoring fail flights because of motor failures). You might consider an Aerotech DMS instead.
• You will almost certainly want to have your fins go through the wall to glue to the motor mount between the centering rings. This is a little more work and weight, but far stronger.
• I would not bevel or sand the fin tip where the rocket will land to help prevent damage to the tip.
• If you'll be landing on a very hard surface (dry lake bed, pavement, gravel, etc.), you may want your fins to sweep forward so the rocket lands on the motor mount first, which can save some damage to the fins.
• You'll need a mentor to get your L1 certification. They can help you with construction details and should also review the design.

 

[lr64]

If you are looking for motors with higher initial thrust, you might find thrustcurve.org useful. Also, if you haven't, ask your mentor what motors would be easy for them to get, and use one of those.

An alternative to higher initial thrust is to design the rocket a bit lighter. Different materials, smaller diameter, etc.

 

[thzero]

Buy a mid power kit and build it fly it. Then try building a mid power rocket of your own design or two

 

[Rschub]

I totally understand the desire to design your own. I am not 15, I am a mechanical engineer with years of experience, and I want to design my own rockets too. I did use a kit for my first rocket.

I recommend that you get a kit for your first rocket, because the parts you will need are all there in one place, and you can see how things are done. This is what I did.

Your design is pretty close to a LOC kit, https://locprecision.com/collections/rockets-4-00-diameter/products/lc-bbx4

If you built this kit, it would serve you well for years, all the way through level 2. It will take many sizes of motors and can be used for electronic deploy or engine deploy.

It will fly fine with just the nosecone on the bottom section, and with the additional upper section later on, which is included. The fin shape and length of the bottom section with nosecone are almost the same as your design. You should know that tube comes in stock lengths, so it is best to plan your designs to accommodate that fact.

It will be cheaper in the long run than trying to find all the parts needed and have them shipped to you. I would order the 38 or 29mm motor mount adapter along with it so you can fly many different motors.

 

[cbrarick]

ahh. can you actually get a CTI H110 where you're at?