RockSim Favor - Pleeze pleeze please

[Fore Check]

Hello,

I'm getting ready for a launch this weekend, and I'm many, many hours away from my "home" computer where my copy of Rocksim is located.

Would someone who has the new AT Mojave Green motor files loaded do me a huge favor?

I uploaded the RockSim file for my Seahawk in another thread a while ago:

https://www.rocketryforum.com/attachment.php?attachmentid=40793&d=1181692895

However, that was before I weighed and balanced it as "flight ready" - so for an accurate sim you'd need to go to "mass override" and set the mass to 2889.9 grams (6.87 lbs) and the Cg at 62.5" from the nose tip.

Then I need a sim run with the new AT J500G with a 10 second delay. Please set it up for a 6 foot rail and "fairly breezy (8-14mph)" winds in the sim conditions.

I'm looking for predicted altitude, maximum velocity, maximum acceleration, optimum delay, and (most importantly) velocity at deployment.

Would someone help a brutha out?

 

[Warren]

I have everything but the J500G eng or rsp file and am having trouble locating one on the web. Any ideas?

 

[Fore Check]

I have everything but the J500G eng or rsp file and am having trouble locating one on the web. Any ideas?

I can't verify the data, but try this:


https://www.rocketryforum.com/showthread.php?t=40658&highlight=mojave+eng

 

[uncle_vanya]

I'm looking for predicted altitude, maximum velocity, maximum acceleration, optimum delay, and (most importantly) velocity at deployment.

Using the J500G file you pointed me to on the forum and the mass override and cg you specified I came up with the following info:

3091.92 ft max height
596.16 ft/s max velocity
699.65 ft/s/s max acceleration
12.02 secs to apogee
54.26 ft/s at deployment
3083.80 ft height at deployment (so a bit early)
Optimal ejection delay: 10.576 Sec.
Velocity at launch guide departure: 86.4917 ft/s

Please note that the landing speed including wind is a little high (nearly 30 ft/s). With these big fins you might want a bigger 'chute.


Details:

229% Upscaled SM-3 Seahawk - Simulation results
Engine selection
[J500G-10]
Simulation control parameters
Flight resolution: 800.000000 samples/second
Descent resolution: 1.000000 samples/second
Method: Explicit Euler
End the simulation when the rocket reaches the ground.
Launch conditions
Altitude: 0.00000 Ft.
Relative humidity: 50.000 %
Temperature: 59.000 Deg. F
Pressure: 29.9139 In.
Wind speed model: Slightly breezy (8-14 MPH)
Low wind speed: 8.0000 MPH
High wind speed: 14.9000 MPH
Wind turbulence: Some variablility (0.04)
Frequency: 0.040000 rad/second
Wind starts at altitude: 0.00000 Ft.
Launch guide angle: 0.000 Degrees from vertical
Latitude: 0.000 Degrees
Launch guide data:
Launch guide length: 72.0000 In.
Velocity at launch guide departure: 86.4917 ft/s
The launch guide was cleared at : 0.166 Seconds
User specified minimum velocity for stable flight: 43.9993 ft/s
Minimum velocity for stable flight reached at: 18.4028 In.
Max data values:
Maximum acceleration:Vertical (y): 699.646 Ft./s/sHorizontal (x): 175.316 Ft./s/sMagnitude: 699.646 Ft./s/s
Maximum velocity:Vertical (y): 592.7503 ft/s, Horizontal (x): 21.8533 ft/s, Magnitude: 596.1614 ft/s
Maximum range from launch site: 2654.24958 Ft.
Maximum altitude: 3091.92186 Ft.
Engine ejection charge data:
Using a delay time of : 10.000 Seconds
Velocity: 54.2621 ft/s
Altitude: 3083.80107 Ft.
Recovery system data
P: Parachute Deployed at : 11.440 Seconds
Velocity at deployment: 54.2621 ft/s
Altitude at deployment: 3083.80107 Ft.
Range at deployment: -356.94031 Ft.
Time data
Time to burnout: 1.441 Sec.
Time to apogee: 12.018 Sec.
Optimal ejection delay: 10.576 Sec.
Landing data
Successful landing
Time to landing: 186.980 Sec.
Range at landing: 2654.24958
Velocity at landing: Vertical: -17.2254 ft/s , Horizontal: 21.8511 ft/s , Magnitude: 27.8242 ft/s

 

[uncle_vanya]

I'm looking for predicted altitude, maximum velocity, maximum acceleration, optimum delay, and (most importantly) velocity at deployment.

3091.92 ft max height
596.16 ft/s max velocity
699.65 ft/s/s max acceleration
12.02 secs to apogee
54.26 ft/s at deployment
3083.80 ft height at deployment (so a bit early)
Optimal ejection delay: 10.576 Sec.
Velocity at launch guide departure: 86.4917 ft/s

I have the CSV export of the simulation data as well if you need it.

Please note that the landing speed including wind is a little high (nearly 30 ft/s). With these big fins you might want a bigger 'chute.


Details:

229% Upscaled SM-3 Seahawk - Simulation results
Engine selection
[J500G-10]
Simulation control parameters
Flight resolution: 800.000000 samples/second
Descent resolution: 1.000000 samples/second
Method: Explicit Euler
End the simulation when the rocket reaches the ground.
Launch conditions
Altitude: 0.00000 Ft.
Relative humidity: 50.000 %
Temperature: 59.000 Deg. F
Pressure: 29.9139 In.
Wind speed model: Slightly breezy (8-14 MPH)
Low wind speed: 8.0000 MPH
High wind speed: 14.9000 MPH
Wind turbulence: Some variablility (0.04)
Frequency: 0.040000 rad/second
Wind starts at altitude: 0.00000 Ft.
Launch guide angle: 0.000 Degrees from vertical
Latitude: 0.000 Degrees
Launch guide data:
Launch guide length: 72.0000 In.
Velocity at launch guide departure: 86.4917 ft/s
The launch guide was cleared at : 0.166 Seconds
User specified minimum velocity for stable flight: 43.9993 ft/s
Minimum velocity for stable flight reached at: 18.4028 In.
Max data values:
Maximum acceleration:Vertical (y): 699.646 Ft./s/sHorizontal (x): 175.316 Ft./s/sMagnitude: 699.646 Ft./s/s
Maximum velocity:Vertical (y): 592.7503 ft/s, Horizontal (x): 21.8533 ft/s, Magnitude: 596.1614 ft/s
Maximum range from launch site: 2654.24958 Ft.
Maximum altitude: 3091.92186 Ft.
Engine ejection charge data:
Using a delay time of : 10.000 Seconds
Velocity: 54.2621 ft/s
Altitude: 3083.80107 Ft.
Recovery system data
P: Parachute Deployed at : 11.440 Seconds
Velocity at deployment: 54.2621 ft/s
Altitude at deployment: 3083.80107 Ft.
Range at deployment: -356.94031 Ft.
Time data
Time to burnout: 1.441 Sec.
Time to apogee: 12.018 Sec.
Optimal ejection delay: 10.576 Sec.
Landing data
Successful landing
Time to landing: 186.980 Sec.
Range at landing: 2654.24958
Velocity at landing: Vertical: -17.2254 ft/s , Horizontal: 21.8511 ft/s , Magnitude: 27.8242 ft/s

 

[Fore Check]

Awesome. Thank you so much.

Regarding that landing speed - I don't remember what chute I put in it in the RockSim file. The last time I flew it I used a SkyAngle Classic II "44". Let's just say the descent was nice and liesurely without lolly-gagging.

Looks like I'm going to try it! That is - assuming that the weather forecast holds true and there aren't gale force winds whipping across the launch site tomorrow....

 

[uncle_vanya]

Does anyone out there have the reload handy to tell us what RDK options it takes? The 10 second delay for a Medium delay seems a little short for optimal - but with +/- 20% variation I guess trying to add a half-second is silly.

In any case, what RDK's does the J500 use? I have one on order and would like to have the info just in case I need a longer delay when I use it.

 

[Fore Check]

Happy Happy Joy Joy!

Well, folks - just checking into the hotel after Saturday launching at 3 Oaks, MI with Team 1.

I'm happy to report that the Seahawk delivered a fantastic flight on the J500G! I'd say the predicted altitude of 3000' AGL (give or take) was pretty darn good.

The breeze was pretty steady at ground level around 10mph, but it looked like it was a little less aloft. I angled the rail into the wind just a bit, and the rocket flattened out at apogee very nicely before deployment.

The flame on that J500 is big and beautiful! Noisy too - an added bonus.

Sorry, no launch pic (I still haven't replaced my digital camera) but Rockets magazine was on hand and they got a great pic and video. Hopefully I can come up with one of their "teaser" pics before too long.

There's a bit more to the story on the flight, though. The rocket separated nicely at apogee, but the SkyAngle chute didn't open. It free fell like a drougless DD rocket as I just stamped my feet chanting "cummon-cummon-cummon...." Amazingly, at about 800 ft or so, the chute opened on it's own. All the cords stretched out nicely and the rocket came in for a gentle landing just west of the flight line. It was like dual deploy on accident! In hindsight, I think I know what I did. I didn't roll the chute very tightly, and when I wrapped it in the nomex blanket, I had to "push" it a little harder than what my gut told me was a comfortable fit. I should have re-packed the chute, but it all worked out.

Better to be lucky than good sometimes....

Special thanks to uncle_vanya for providing me with the information such that I was willing to try it. It was a sweet flight.