OpenRocket newbie. Achieving best flight height possible

[Poleena]

Hello! I‘m new at modelling with OpenRocket-15.03.

I want to build a rocket with the I405 motor by Loki Research, parachute and a starting pintle.
Of course, I want my rocket to be fast and my goal is to make it fly as high as possible.

Could you give me any general guidelines? Maybe, what to start with or which settings to adjust?

Thanks for your replies !!

 

[Adrian A]

Hello! I‘m new at modelling with OpenRocket-15.03.

I want to build a rocket with the I405 motor by Loki Research, parachute and a starting pintle.
Of course, I want my rocket to be fast and my goal is to make it fly as high as possible.

Could you give me any general guidelines? Maybe, what to start with or which settings to adjust?

Thanks for your replies !!

Download RASAero for your simulation, but you'll still want OpenRocket to estimate your mass and CG.

 

[Buckeye]

OK, I'll be the grumpy old guy.

Looks like you are new here and you are 15 years old. What is is your rocketry experience? How do expect to fly a Level-1 restricted motor? What is a pintle?

I'd suggest you do some homework. Read Stine's "Handbook of Model Rocketry." Search the forum before posting.

High and fast all depends on mass and aerodynamic drag...and stability for safety. You can play with these parameters in Open Rocket.

</grumpy old guy>

 

[markkoelsch]

OK, I'll be the grumpy old guy.

Looks like you are new here and you are 15 years old. What is is your rocketry experience? How do expect to fly a Level-1 restricted motor? What is a pintle?

I'd suggest you do some homework. Read Stine's "Handbook of Model Rocketry." Search the forum before posting.

High and fast all depends on mass and aerodynamic drag...and stability for safety. You can play with these parameters in Open Rocket.

</grumpy old guy>

So, what are you trying to say[emoji3]I think I can sum it up as flying a minimum diameter, mass and drag optimized rocket with little to no experience is not a good place to start.


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[scsager]

Hello! I&#8216;m new at modelling with OpenRocket-15.03.

I want to build a rocket with the I405 motor by Loki Research, parachute and a starting pintle.
Of course, I want my rocket to be fast and my goal is to make it fly as high as possible.

Could you give me any general guidelines? Maybe, what to start with or which settings to adjust?

Thanks for your replies !!

Hi Poleena, welcome to the Forum!
To get the maximum speed and altitude from any 38mm rocket motor, just build a minimum diameter rocket. Use very light and strong materials like carbon fiber. Best design is 3FNC, and no launch lugs or buttons. Build a "Launch Tower" to minimize drag, or use Fly-Away rail guides from AMW. Recovery and tracking (RF or GPS) is a big consideration due to the expected altitude. If you can get a JL Chute Release to fit, that would also help, however you may need to go DD if your sim shows the full delay on the I405 is too short.

OPEN ROCKET will help with the variable dimensions for the nosecone, air frame length and fin shape and size. Most folks would start with 5:1 for the nose and 10:1 for the air frame, and then use the "optimize" tool in Open Rocket to make adjustments to maximize performance.

Your goal is a high performance rocket that will break the speed of sound, and go 1.5 miles high. (based on a quick OR sim of a blackhawk29 upscaled to38). If you're not understanding some of the things I wrote, you might not be ready to attempt this.

Good Luck!

Oh - I almost forgot... What's a Pintle???

 

[MikeyDSlagle]

A pintle is the pin out of a hinge isn't it? But what's that got to do with rocketry?

 

[JJSR]

pin·tle
&#712;pin(t)l
noun
one of the pins (on the forward edge of a rudder) that fit into the gudgeons and so suspend the rudder.

I'd like to see a rocket with a rudder, wonder how it'll work with anything LOKI??

 

[Adrian A]

Pintles and rocket propulsion do go together:
https://en.m.wikipedia.org/wiki/Pintle_injector
But pintles and amateur solid rocket motors, not so much.

 

[BDB]

Altitude and speed do not necessarily go hand in hand. You can see some of my data in this thread, where rockets with added weight (in the form of fiberglass reinforcement) are predicted to fly higher than their lighter counterparts. This is especially true for motors with high initial thrust, like the Loki I405 (get choice; one of my favorite motors). In essence, the short, powerful thrust generates so much momentum that most of the flight profile happens when the rocket coasts upwards after motor burnout. The heavier the rocket, the more it's momentum (p=mv), the higher the altitude. The trade off is that your max velocity will be lower with a heavier rocket, so a slower flight can actually result in a higher altitude.

 

[Nytrunner]

I'm just here to find out how he wants to use the starting pintle with the I405 lol.


Openrocket is great for starting a design, but something that's critical to remember is that its a computer simulation: Garbage In, Garbage Out.
First example that springs to mind is when you get around to buying parts, you'll need to weigh them and backfill Openrocket so that the component mass is the same.

As stated above, the forum doesn't know you or your experience. A clarifier I'll ask is: Are you new to Rockets themselves (building and launching them, theory doesn't count lol), or Just new to Openrocket software.

Good luck exploring rocketry!

 

[GrouchoDuke]

If you're looking for a purpose built I-motor 38mm go-high rocket, how about: start with a Go Devil 38, put together a small flight computer + tracking package, decide on dual or single deploy based on your club's launch location's requirements, reduce the rocket length as much as you can, reduce the fin size to keep the stability high enough for what you need, make the fins from 2mm carbon so you won't have any issues near Mach 2, skip the Loki I405, go with the CTI I216, build a launch tower...and go fly high!

One gotcha for purpose built rockets though: if you optimize for a big motor, smaller motors might not give you the CG you need to stay stable.

Another gotcha: purpose built rockets can be a pain in the bum.

 

[Poleena]

I&#8216;m new to rockets themselvet. This is my very first experience. That&#8217;s why I&#8217;m asking silly questions.

 

[Steve Shannon]

Pintle may have been an auto correction. The OP may have intended to ask about a “starting point.”


Steve Shannon

 

[Poleena]

Yes, exactly. I haven&#8217;t noticed it. Thank you for the correction!

 

[Poleena]

If you're looking for a purpose built I-motor 38mm go-high rocket, how about: start with a Go Devil 38, put together a small flight computer + tracking package, decide on dual or single deploy based on your club's launch location's requirements, reduce the rocket length as much as you can, reduce the fin size to keep the stability high enough for what you need, make the fins from 2mm carbon so you won't have any issues near Mach 2, skip the Loki I405, go with the CTI I216, build a launch tower...and go fly high!

One gotcha for purpose built rockets though: if you optimize for a big motor, smaller motors might not give you the CG you need to stay stable.

Another gotcha: purpose built rockets can be a pain in the bum.

I&#8217;m not going to build a real rocket in fact. I just want to see the connection between different parameters and how they affect the rocket flight height. But thank you so much for your advice!

 

[Poleena]

Altitude and speed do not necessarily go hand in hand. You can see some of my data in this thread, where rockets with added weight (in the form of fiberglass reinforcement) are predicted to fly higher than their lighter counterparts. This is especially true for motors with high initial thrust, like the Loki I405 (get choice; one of my favorite motors). In essence, the short, powerful thrust generates so much momentum that most of the flight profile happens when the rocket coasts upwards after motor burnout. The heavier the rocket, the more it's momentum (p=mv), the higher the altitude. The trade off is that your max velocity will be lower with a heavier rocket, so a slower flight can actually result in a higher altitude.

Thank you very much! I really appreciate your help.

 

[Poleena]

So, what are you trying to say[emoji3]I think I can sum it up as flying a minimum diameter, mass and drag optimized rocket with little to no experience is not a good place to start.


Sent from my iPhone using Rocketry Forum

Thank you!

 

[dhbarr]

If you're mostly wanting to play with simulations, I'd recommend downloading a few samples from the forum here and seeing what does what.

Here's a sample group of files to get you started:

https://www.google.com/search?q=sit...+l3&oq=site:rocketryforum.com+(ork+OR+rkt)+l3

 

[markkoelsch]

Thank you!

You are welcome. I see you are just poking around playing with simulation. That said, if you do move to building and flying I do suggest something a little slower to start with.


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[Steve Shannon]

I’m not going to build a real rocket in fact. I just want to see the connection between different parameters and how they affect the rocket flight height. But thank you so much for your advice!

Then you may also want to play around with Kerbal Space Program: https://kerbalspaceprogram.com/en/

 

[LithosphereRocketry]

Then you may also want to play around with Kerbal Space Program: https://kerbalspaceprogram.com/en/

Yes, definitely.
https://xkcd.com/1356/

 

[OverTheTop]

Welcome to the forum and the rocketry community!

As someone said earlier, speed and altitude sort of go together, but you usually select to optimise only one of these. If you want to go for speed, you need a bird that is very light, but strong enough to stand up to the speeds that the biggest motor you will fly it on can be withstood. If you are going for altitude then there is an optimum mass that will get you there, balancing the aerodynamic drag with the kinetic energy of the rocket after allowing for the thrust profile of the motor and gravity losses that it works with. Simulators can help you here to get you the numbers you need.

If you are going for the absolute best of either of these the smoothing of the design components and surface finish are important to minimise drag in both cases.