Rocsim File for The Dude?

Does anyone know where I can get a Rocsim file for The Dude? (Yes, THAT rocket...) I'm planning on flying one at LDRS with an AT F12 and a Quark for deploying the chute at apogee, and I want to see what the velocity profile looks like. Thanks in advance!

Why not simply use thrustcurve. All you really need is the OD of the rocket, empty weight, and the mmt diameter and length and guess the cd. My guess the sectional density is so low, drag will dominate. A review says it folds over with the AT F12, but flies great on an Estes E9. Not sure why it doesn't work with the F12 unless the OP did not have it inflated enough so it was stiff. IMO an Apogee F10 might be the best motor but you would have to modify the MMT to 29 mm.

You might want to fill it with helium to lower the weight by 2oz. BTW I don't think the chute is really necessary from the flights I've seen.

https://www.rocketreviews.com/the-dude---estes-2199-2001-2003.html

https://www.rocketreviews.com/fligh-log-dwayne-shmels-estes-the-dude-7576.html

https://www.rocketreviews.com/dwayne-shmels-estes-the-dude-3331.html

Bob

The Dude would be hilarious if the rules of physics and chemistry were such that if filled with helium, it would simply continue ascent after thrust and just keep going up, up and away.

Maybe a Dude filled with helium, that ejects it's motor and fin can assembly, so the balloon portion just keeps going???

That would be cool dude!

The Dude is a cool rocket, I think I still have one somewhere

bobkrech said:

Why not simply use thrustcurve.

Bob

Click to expand...

The OP asked for a velocity profile, which thrustcurve does not generate.

Is the Dude cross-section truly circular or more oblong?

Who really need a detailed sim for this rocket. The velocity profile is pretty simple: slow to none and then slow again.

All you need is a simulator that requires the diameter, weight without motor, an .eng and a cd. In RASAero it takes about 2 minutes.

Assuming a 8" OD and ~10 oz empty weight, the rocket has cd~0.24 and reach s peak velocity ~ 140 fps at 1 second and drops to ~ 120 fps at burnout.

Apogee is ~950' @ ~10 seconds. Terminal velocity would be ~80 fps streamlined but everyone I've seen comes in almost horizontal so the descent rate would be much slower.

I'd be surprised if it gets that high as most weathercock severely.

Bob

I kinda kludged up an OR file with a 1-mil PVC body tube and NC. I'm not sure how accurate the sims are, but it "looks" about right. It came out the same as Bob's RASAero sim, good enough. I plan on gluing some stringers to the outside to help stiffen it, I too am a little concerned that the F12 may be too much, but its peak thrust is actually less than the D12 and it's a regressive curve whose peak occurs before the rocket is even off the rod so I think it will OK.

The F12 actually is a F16 and the average thrust is above 12 N for 2 seconds. https://www.thrustcurve.org/simfilesearch.jsp?id=645 I found one flight report of a Dude with a F12 in rocketreviews and it was not successful. https://www.rocketreviews.com/fligh-log-dwayne-shmels-estes-the-dude-7576.html I don't know if it 4+G acceleration or the high velocity that causes the problem.

If you could kluge up a 29 mm mount with an Apogee F10 you would have a lower acceleration for a longer time and ultimately reach the same velocity as you would with the F12. Then again, it might just delay the disassembly. https://www.thrustcurve.org/simfilesearch.jsp?id=1174

But it would be very impressive if it succeeds.

Bob