First Model Rocket launch in 15 years!

Hey everyone!

The past week I have been eating, drinking and sleeping everything rocketry based. I've learned so much about homemade motors, hybrid motors, and recently I've been reading about toroidal aerospikes. Those seem awesome! So, a quick back story, when I was a kid, 8-10 years old, I built rockets. Information was not as easy to come by then, and I mostly learned through the library and trial and error. I had a big red rocket that flew on a D motor, and when I tried an E, I lost it. I also managed to build and fly my own custom smaller rockets based entirely on balsa wood and cardboard tubes and B motors. Well that was awhile ago, but I got the bug and bought a model rocket after work last Friday, painted and assembled it on Saturday, and flew it 3 times on Sunday at my buddies ranch.

I bought a Quest brand Seeker rocket from HobbyTown USA for ~$38 which included a launch pad, and three motors [A6-4,B6-4,C6-3]. I haven't touched a model rocket since I was small child [only 27 now] but it feels like forever ago. If I thought I had the itch coming back just reading as much as I could about the hobby, this launch sealed the deal. I'm now reading on how to make a custom rocket that I hope will carry an electronics payload to 5k-7k feet and return everything safely and reliably. I am very excited to find some new friends here and learn as much as I can, as quickly as I can. I am a Hardware Engineer by day in Biometric Security, but I have aspirations of building my own launch vehicles. Hope you enjoy!

Eric
San Antonio, TX

[video=youtube;yOXwJcvK8QE]https://www.youtube.com/watch?v=yOXwJcvK8QE[/video]

Welcome Eric ! Including a launch video in your intro post here is pretty cool. Your rocket range looks awesome, nice to have friends with a ranch. You may want to take a look at Art Applewhite's Texas launch page at https://www.artapplewhite.com/launches.html.

As you may know, discussing specifics of propellant formulations is restricted on here just 'cause of the world we live in. The rules for gaining access to the Research forum are: https://www.rocketryforum.com/showthread.php?17943-Research-Forum-Access Finding some locals who are doing that kind of thing may be a better way to go.

Welcome!

Great first post, this forum loves photos and videos.

Edited OP for removal of propellant info. I have been researching local Tripoli & NAR sanctioned clubs around me, and I'm close to sending my paperwork off to join Tripoli. I don't know if I'll join NAR, as some I'd like to pursue some really experimental stuff later on after I get my L1-3 certs in the coming years.

GonMD said:

Edited OP for removal of propellant info. I have been researching local Tripoli & NAR sanctioned clubs around me, and I'm close to sending my paperwork off to join Tripoli. I don't know if I'll join NAR, as some I'd like to pursue some really experimental stuff later on after I get my L1-3 certs in the coming years.

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No worries, nothing in your initial post to worry about. Sounds like you have a good plan going forward.

Welcome to rocket world. The next generation of BAR.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

So I've been tinkering with a design in Solidworks 2012 I thought of on my way home from work. The nosecone will be 3D printed (resin DLP method) as well as the engine housing which will be two parts which will capture the motor, with the lower section also having the fins (quantity 6) as part of its structure. I figure I can save some weight by not using epoxy or hardware to secure them in place and will attach to the static section of the housing with a quarter turn locking system. I'm calling it the Daedalus I. I'm fixing to pull the trigger on a section of carbon fiber for the rocket body which is dictating the custom engine housing and nosecone.

I'm also looking at building an altimeter/pressure/temperature logger off an Arduino mini pro and one of these guys: https://www.sparkfun.com/products/11084

Looking at using an 24mm E motor for this vehicle. So far the whole assembly minus electronics, and one part of the engine housing is weighing in at .3 of a pound, so I think I am on the right track. I'd love to hit 2,000 feet and be able to record some data and return everything safely.

Since I'm a bit new at this, I'd love to hear some feedback on design!



Thanks for looking!
Eric

I think you're ok. I've done several with 6 fins, it looks like they need to be bigger but with 6 fins they really don't. Just keep as much of the weight forward as you can.

Welcome Eric.
If you are going to do many rockets as your own designs and scratch builds, you might want to invest in RocSim from Apogee.
If you don't want to pay after the free trial expires, there is open rocket many use here. It's a free/make donation software much like RocSim.
That will help give you a better handle on your CG and CP so you have a good idea of the stability of your designs.
And always load the motors you plan to use to make sure when they are fully loaded they are still stable.

Hey all. I've got a few questions regarding Open Rocket.

1. Do you guys use a mass component as wadding?

2. Putting electronics in as ballast in the nose cone. Good idea or bad? I feel like it would be a good place for them so long as the recovery system (24" nylon ripstop) deploys as it should.

3. I've got a decent motor picked out I think. An Apogee E6-8, but the numbers don't look particularly overwhelming as you can see in the SS. Is this about normal?

4. How much can I trust the Stability cal number? I seem to be hovering around ~2

5. Finally, I feel like the CG and CP are decently spaced and in good positions from what I've been seeing online. If someone more experienced tells me otherwise, I'll probably start ordering components tomorrow.

Excellent ...at least you make it ...wish i can start and have the right software to help me in the design ...

why you don't use RockSim Pro..its better

GonMD said:

Hey all. I've got a few questions regarding Open Rocket.

1. Do you guys use a mass component as wadding?

2. Putting electronics in as ballast in the nose cone. Good idea or bad? I feel like it would be a good place for them so long as the recovery system (24" nylon ripstop) deploys as it should.

3. I've got a decent motor picked out I think. An Apogee E6-8, but the numbers don't look particularly overwhelming as you can see in the SS. Is this about normal?

4. How much can I trust the Stability cal number? I seem to be hovering around ~2

5. Finally, I feel like the CG and CP are decently spaced and in good positions from what I've been seeing online. If someone more experienced tells me otherwise, I'll probably start ordering components tomorrow.


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Welcome.
I got back into Rocketry in August of 13' for the fourth time, but this time there is the Internet and this Forum, so I'm back to stay.

GonMD said:

Hey all. I've got a few questions regarding Open Rocket.

1. Do you guys use a mass component as wadding?

2. Putting electronics in as ballast in the nose cone. Good idea or bad? I feel like it would be a good place for them so long as the recovery system (24" nylon ripstop) deploys as it should.

3. I've got a decent motor picked out I think. An Apogee E6-8, but the numbers don't look particularly overwhelming as you can see in the SS. Is this about normal?

4. How much can I trust the Stability cal number? I seem to be hovering around ~2

5. Finally, I feel like the CG and CP are decently spaced and in good positions from what I've been seeing online. If someone more experienced tells me otherwise, I'll probably start ordering components tomorrow.


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To answer your questions:

1. You can, and it'll certainly isn't a bad idea, but IMO it's overkill as the weight of the wadding is negligible.

2. Good. Just keep in mind that if the electronics in question are barometric altimeters, their readings will be less accurate if the air sampling hole is drilled on the cone (one way to avoid this is by drilling the hole through the airframe and shoulder... Just be sure to line them up for flight.

3. It looks fine. Just be sure to check the trust to weight ratio. It should be greater then 5:1.

4. In my experience OpenRocket is very reliable. I would trust it.

5. 2cal is perfectly fine. If anything it's a bit too much. Ideally one wants about 1 cal, but this is usually impractical if the rocket is designed to fly bigger motors as well. Just remember the higher the stability, the more likely the rocket will weathercock on windy days.

GonMD said:

... Since I'm a bit new at this, I'd love to hear some feedback on design!

View attachment 248610

Thanks for looking!
Eric

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Welcome back!

Since you asked, IMHO the fins are a bit small, even if you have six. I would think about increasing the span of at least 3. You don't need to upscale the fin (but you could), I just think increasing the span (about twice as long).

That said, it would likely fly well as is in no to light winds. I think it may get a bit dicey in launch winds around 10-15 mph.

Greg