Estes Xtreme RockSim Design

[tooth]

Has anyone here created a Rocksim or OpenRocket file for the Estes Xtreme they would be willing to share? I’m VERY new to the software and don’t have much confidence in my own input. I’ve looked all over at the regular sources for the file but have come up empty so far.

My wife and I are starting the NARTREK certification program and wanted to use this kit for our streamer duration. Thought it would be wiseto use the program to fine tune engines and parachute requirements. Thanks for any help.

 

[cls]

enjoy doing NARTREK! what a great variety of rrocket projects.

do you have an Xtreme kit already? if you can measure the parts we can put together a sim.

 

[tooth]

I really appreciate that. We're both excited to try the different build requirements, and more than a little afraid of some of them, lol.
We do have the kit, parts page attached:

The body tube is 12" long, I measured it at 16mm outside diameter
The nosecone is plastic, 4 7/8" long from tip to where the shoulder starts
The fins are cardboard, root length 4 1/4", 1 3/8" at the widest point, that point is 3 1/4" back from the tip of the fin

I really appreciate you tackling this. I'm going to jump into Rocksim and try to build it too so I can learn, but it will be VERY reassuring to see someone else's file who actually knows what they are doing

 

[neil_w]

If you’re interested in playing wit OpenRocket, you can open up the “simple model rocket” example and just tweak each part to your measurements. It’s an easy way to get started. Then post your file here and we’ll critique it.

 

[cls]

oh gosh, this is literally the easiest design to model!

the airframe tube is called BT-20 size, it is 18.something mm diameter outside.

if you want to do it from scratch:

1. start Open Rocket, or Rocksim.
2. hit File -> New
3. select nose cone. Choose Estes, PNC-20 something. doesn't matter which one, because in the nose cone dialog select "conical" shape, set the length to 4.75 inches
4. select body tube. Choose Estes BT-20, 18 inch; seet the length to 12 inches.
5. select fins, choose trapezoidal, enter the root length, chord, position.
6. etc for the strreamer, shock cord, launch lug, motor block (Estes BT-20). I didn't add mass for the motor clip, you can if you want.

that's it. not much to it. probably the hardest part is just getting started.


if you want to modify an existing design file, start with an Estes Yankee. it's pretty close. youi'll have to change th4e nose cone shape and dimensions, and fin dimensions, and body tube length.

my Open Rocket file is attached. The simulation for C6-5 says apogee 389 meters, that's about 1275 feet. The package claims "up to 1600 feet" which would be about right at the Estes factory in Colorado, 5000 ft altitude, and with a fine paint job.


expect half that altitude with a B6-4, and half again with an A8-5, and half again with 1/1A6-2.

 

[cls]

I really appreciate you tackling this. I'm going to jump into Rocksim and try to build it too so I can learn, but it will be VERY reassuring to see someone else's file who actually knows what they are doing

ha ha! as if I knew what I am doing!

with all simulations, and computers in general, the rule is "garbage in, garbage out." keep refining the simulation. fix up the parts sizes, actual weights, finish quality, and atmospheric conditions and altitude at your launch site.

eventually the simulation will match actual flights to within a percent or 2. the rough design I posted is certainly within 10%, more likely +/- 5%.

 

[neil_w]

Remember that with any sim, when you're finished building the rocket you're going to want to weigh it and measure CG, and then apply those values as overrides in the sim model. If you don't already have a little scale, get one... they're cheap on Amazon and super useful.

 

[kuririn]

The Xtreme is the same as the Hi Flier except with a longer airframe and different nose cone.
The fins and body tube diameter are the same.
So take the Hi Flier sim file and do the two mods and voila, you have an Xtreme sim file.
Here's one downloaded from EMRR:

 

[tooth]

I can't thank all you kind folks enough. Very helpful all the way around! I'm going to jump into this thing!

 

[CalebJ]

The Xtreme is the same as the Hi Flier except with a longer airframe and different nose cone.
The fins and body tube diameter are the same.
So take the Hi Flier sim file and do the two mods and voila, you have an Xtreme sim file.
Here's one downloaded from EMRR:

Minor point - the Xtreme uses card stock fins vs the balsa fins on the Hi Flier.

 

[tooth]

My wife built a beautiful Xtreme, and from what I could tell on it's maiden flight the Rocksim predictions were tracking pretty well. Other than that high altitude cross wind no one knew about. I think she took it better than I did.