Virtual Iron Rocketman Contest Ready to Go!

[EMRR]

Results are being posted. Watch each day as I get caught up!

 

[PunkRocketScience]

Yeah! Thanks Nick!

 

[EMRR]

Final Standings Posted!

 

[PunkRocketScience]

Congrats to all of the entrants! I hope the newbies enjoyed their experience and will keep coming back! I rarely place above the middle of the pack, but I enjoy the challenge! I can't wait to face you all again in the neck one.

Chan and Nick-

I first want to start off by saying thank you for sponsoring and running the contest. I'm not disputing the final standings. You ran the contest and made the calls as to what was qualified and not. No sour grapes here. I placed much better this time than in the last conest, I just wanted to point something out.

That being said, for future contests a clearer indication of what a "realistic" recovery device should be made. I thought I was pushing it by jamming a 60" streamer into a bt-20. Not an easy fit, but I have seem similar done in contest flying. Jamming a 500" streamer into a bt-50 is not very realistic, even if it does fit "virtually" in the software. Bruce's mastery of the subtleties (sp?) of rocksim are amazing and his entry got approved, so more power to him! I can't comment as to the size of the recovery devices in the other models as the files haven't been posted yet, other than David Allen's model, which is only slightly larger than mine but described as having "some of the largest streamers in the competition." I'm not saying I didn't think about super-sizing my streamer, but the theme of the contest was to simulate a real world contest....


Bob-

Once again, congrats on a decisive win! Do you think that you could be prompted into writing an article on your processes for creating and testing your models? You obviously have rocksim's logic dialled in and I'm extremely curious about your methods! I tested the heck out of my model and thought I'd been pretty thorough this time, but still got skunked!

 

[teflonrocketry1]

Eventhough I used these extra long streamers, they didn't help me in the competition at all, I didn't even place amoung the top four in C-SD!

I have been working on getting some extremely long (100') streamers into very small body tubes (BT-20). The streamers are made from the Teflon Pipe Thread Sealant Tape that I typically use. I can compress an entire 100' roll up to easily fit into a BT-20 tube with room to spare. I put an entire roll of thread seal tape into 1000 lb arbor press. The problem is getting the entire length of the steamer to unfurl, so far I only got about 50 feet of streamer to deploy. As far as getting 500' of steamer into a BT-20 tube, I know it is possible, but getting all 500' of it to deploy is another issue. My entry was designed around these long streamers. Since I can get at least 500 feet of one of these streamers into a BT-20, then it is a realistic recovery device. I had the same 5% chance for a recovery device failure as everyone else but there was no competition penalty for unfurling an extra long streamer.

Three thermal events for one flight is also unrealistic!

My thanks to Nick for hosting yet another RockSim virtual rocketry event and to Chan for judging the contest.

I still haven't figured out how to win one of these virtual rocketry competitions.

Bruce S. Levison, NAR #69055

 

[PunkRocketScience]

Wow! I'm amazed that that much streamer will fit into that size airframe! I'm not saying that I don't believe it, I'm just suprised. Thank you for letting me know.

I guess what I am suggesting is some definative guideline as to what "realistic" is. It'd be much easier to wrap my head around x" by y" streamer or x" 'chute in a bt-20 maximum. I realize that this is something of an experience thing. I just learned a lot from our post. Another notch of experience toward placing better.

Thanks Bruce. Please don't take it as me saying you didn't deserve your placing, your design obviously rocked!

 

[Vanel]

As the one who lost both virtual rockets, I must say that this virtual contest felt quite realistic to me - reminds me of my performance at my first NAR competition Once again I am middle of the road, but feel lucky that I did not place lower, considering I DQ'd one event and had to sit one out.

I would also like to thank Nick and Chan for another fine contest - this one felt like a real competition. It's a shame more folks didn't enter, as that would've only enhanced the fun!

Hats off to Bob, who majorly deserved his win - I'm surprised he didn't smoke his computer running all those simulations

The only whine I wish to make involves not the contest, but what seems to me to be a slight flaw in the RockSim competition settings. Recovery failures should be somehow tied to the size of the chute or streamer packed into the body tube. The bigger, the tighter the fit, and hence the failure chance should be greater. A 36" chute packed into a BT-20 should have a greater chance of failure - materials being the same - than a 12".

It was great fun folks!

 

[teflonrocketry1]

I disagree about the realism factor in this event! The weather conditions that were chosen are purely fictional. Isn't 1.571 degrees Latitude somewhere up near the north pole? Would it ever get to 75 degrees F there? Why was the weather the same for all four days over the contest? That rarely happens in the real world. There is a bug in RockSim that makes it possible for three thermals to occurr during a given flight just as likely as it is for one thermal. How likely is it in the real world that thermals occurr periodically and 656 feet apart? I lost one of my virtual rockets to this software bug! Bob Cox was the best at exploiting thermals for the streamer duration events.

Bruce S. Levison, NAR #69055

 

[PunkRocketScience]

I believe latitude is measured from the equator, so 1.571 degrees is somewhere very tropical....

 

[BobCox]

Originally posted by PunkRocketScience
Bob-
Once again, congrats on a decisive win!

Thanks. It was actually a lot closer than it looked because of the way the scoring system worked. If Dave Allen or Bruce Levison had caught the lucky thermal instead of me in the streamer duration, they would have won.

What I want to know is where the heck did this Dave Allen come from? He had the best debut of anybody since Dave Austenberry won VRC#5. Very impressive.

I tested the heck out of my model and thought I'd been pretty thorough this time, but still got skunked!

Too bad there weren't any style points in this contest. I got a big laugh out of your LOG. As soon as I saw it, the Log Song from the Ren & Stimpy show immediately started running through my head. Thanks for brightening my day.

Do you think that you could be prompted into writing an article on your processes for creating and testing your models? You obviously have rocksim's logic dialled in and I'm extremely curious about your methods!

I think I offered to write an article like that after VRC#4, but instead I ended up being the guest judge for VRC#5. I included several hints in the directions for that contest.

Maybe I could pull together an article with some of my favorite VRC tricks. (I don't want to give away all my secrets, though). Would anybody else be interested?

 

[BobCox]

Originally posted by teflonrocketry1
I disagree about the realism factor in this event! The weather conditions that were chosen are purely fictional. Isn't 1.571 degrees Latitude somewhere up near the north pole? Would it ever get to 75 degrees F there?

Originally posted by PunkRocketScience
I believe latitude is measured from the equator, so 1.571 degrees is somewhere very tropical....

Angles are entered into RockSim in degrees, then converted to radians for the calculations. There is a bug in the RockSim results file that displays the radians but the label says degrees. Bruce is correct, 1.571 radians would be at the North Pole. Well, if you want to be really picky, the North Pole is at 1.570796 radians. Rounding up to 1.571 would mean you're MORE than 90 degrees north, which is impossible. Not that it matters, since I don't think RockSim uses the latitude for any of the calculations anyway.

In reality, the ground level and the temperature were chosen to approximate the conditions at NARAM 2005 in Ohio, which was hosted by Chan's club.

Originally posted by teflonrocketry1
Why was the weather the same for all four days over the contest? That rarely happens in the real world.

To make the judging simpler. It was already complicated enough with up to five different models per contestant, flying in arbitrary order.

There is a bug in RockSim that makes it possible for three thermals to occurr during a given flight just as likely as it is for one thermal. How likely is it in the real world that thermals occurr periodically and 656 feet apart? I lost one of my virtual rockets to this software bug!

That's why I HATE thermals. I whined to Chan many times before and during the contest how much I HATE thermals and asked him to turn them off. He didn't. I wasn't happy about it, but those were the rules we agreed to play by so that's what I designed for.

Bob Cox was the best at exploiting thermals for the streamer duration events.

I wish I could say that I planned that, but it was just blind luck. Since Chan wouldn't disable the thermals despite my whining, I used a smaller streamer and chute than I really wanted because I was so afraid of drifting out of bounds.

I find it ironic that the thermals ended up helping me as much as they did. I certainly didn't intend to exploit thermals -- I was hoping to avoid them.

 

[EMRR]

All Files are posted. The contest is officially over. I am publically asking Chan to manage the prize selection and information gathering. He may need to contact the winners directly since our local area just upgraded equipment to DSL2+ and now I can no longer get to Yahoo (Announcement List), Quicken, Estes, Estes Educator, etc due to this upgrade!

I have to buy a new router that has an MTU adjustment, whereas, mine is fixed. Thanks Microsoft!

What you all need to give Chan is your name, mailing address, good e-mail address.

Prizes are:

A) Model Minutes US- (1) G200 Heavy Carrier

B) QuickBurst- $10 Gift Certificate for something of your choice!

D) FlisKits - $20 Gift Certificate for something of your choice!

E) ASP - $10 Gift Certificate for something of your choice!

F) Apogee Components - (1) CD-ROM of the "Building Skill Level 2 Model Rockets" by Tim Van Milligan

G) Chan Stevens - (1) Semroc Hydra VII

Bob Cox has already claimed the Qmodeling

Winners:

1) Cox (C) QModeling - (1) BULLPUP)
2) Allen
3) Levison
4) Paquin
5) Pontikos
6) Mullin
7) Cooke

David Allen, you're up. Be sure to send Chan the information.

Also, on a final note. I love the post contest discussion it makes for better future contests. I thought this one, at least from an outside point of view, to be the most complicated.

Claude Paquin is up next as our host and judge!

Then we need to all encourage Bruce Levison to host and judge a contest.

Regards,
Nick

 

[chanstevens]

A couple notes on the realism factors:

As Bob noted, the intent on weather was to simulate NARAM47's field. I didn't catch the latitude/longitude settings at all until it had already been posted, so didn't feel it would be right to change them. I don't know that this had any impact on flights. For what it's worth, I'm guessing that's the default, as I've never touched my latitude/longitude settings since buying Rocksim 5.0. The 900 feet AGL was, indeed, the elevation for NARAM47.

Bruce & I debated the streamer thing quite a bit. I specifically intended the "realistic recovery" clause to prohibit some of the obscenely sized streamers we've seen in the past. Bruce waged a solid argument, backed up by real-life tests, though I still say that streamer has a zero percent chance of deploying. Ultimately, I had to drop back and let Rocksim be the judge, as it's not subjective. Rocksim displays the streamer just barely fitting in his tube ID. Buggy? Sure, but as Bruce pointed out, that moster streamer was really not that effective.

Dave's submission was DQ'd twice for streamer and/or motors not fitting. He scrambled at the last minute to make sure everything fit.

I also feel terrible about Bill Cooke's luck. I had hoped recovery failure could be set based on deployment speed or size of streamer. Not the case. As it turned out, I think 3 different "safe" flights in drag or OSL DQ'd for random recovery failures.

On the thermal front, there were zero 3-thermal flights, and only a couple doubles. I ran graphs of every flight to see thermal effects. I think the thermals were amazingly realistic based on my experience on that field over 5 years. It's an ironic shame after all his whining, Bob caught two of the best thermal breaks in the meet, and never lost a single model.

--Chan Stevens

 

[chanstevens]

Originally posted by PunkRocketScience
I can't comment as to the size of the recovery devices in the other models as the files haven't been posted yet, other than David Allen's model, which is only slightly larger than mine but described as having "some of the largest streamers in the competition." I'm not saying I didn't think about super-sizing my streamer, but the theme of the contest was to simulate a real world contest....

I probably wasn't clear enough in the commentary. Dave had a tiny airframe, and therefore had to use a tiny streamer. I don't recall the exact size (files are on my work PC), but what I was trying to point out is that his entry couldn't fly some of the 8" streamers or 30-40" chutes of the other flyers.

The key seemed to be going for 13mm--the three skinny entries took 1, 2 and 4, and 2 of those contestants are rookies. Dominant performance and approach to design.

Bruce's 18mm overcame most of the size disadvantage, and he was probably only 1-2 flights away from sweeping the field for first place. He just couldn't catch a decent thermal when he needed one.

 

[Vanel]

Originally posted by chanstevens
I also feel terrible about Bill Cooke's luck. I had hoped recovery failure could be set based on deployment speed or size of streamer. Not the case. As it turned out, I think 3 different "safe" flights in drag or OSL DQ'd for random recovery failures.

Hey man, that's life in the virtual world Don't sweat it - as I said, I thoroughly enjoyed this contest, as it seemed to be more "real world" than the others. My opinion, of course.

I had a lot of fun, and even placed well enough for a prize. Ain't nothing to feel terrible about.

 

[teflonrocketry1]

There is actually a way to "controll" thermals beyond the competition settings in RockSim. There are so many flaws and issues with the competition settings that I would prefer if they were not used in these virtual contests. I actually tried to exploit one of these flaws in the software so I wouldn't get any thermals during some of my flights. In hindsight, this probably cost me first or second place since I lost the C-SD event. The one thermal that my entry did see, that took my 2nd B-PD flight, was a calculated risk I was willing to take. Chan may be able to figure out what it is in the software that supresses thermals by looking at my entry and those from the others.

The recovery failures were set to the 5% level, yet Chan mentions three DQ'd recovery failures out of the 22 flights in drag and OSL, that is 14%, almost three times what is expected! I have many more issues about how the competition settings in RockSim behave. I wonder what the descent resolution was that Chan used for this contest? Typically descent resolution is set to 1 sample per second. Has anyone else bothered to look at running competition settings at different descent resolutions?

Bruce S. Levison, NAR #69055

 

[BobCox]

Originally posted by teflonrocketry1
There is actually a way to "controll" thermals beyond the competition settings in RockSim.

How do you do that? The only way I could find was to use a small recovery device so that the descent speed was so fast it would overcome the updraft of the thermal. Do you know of a different technique?

There are so many flaws and issues with the competition settings that I would prefer if they were not used in these virtual contests.

I tend to agree with you there. It really sucks when you spend a lot of time on a good design and then a random "bolt-from-the-blue" results in a DQ or crash.

The recovery failures were set to the 5% level, yet Chan mentions three DQ'd recovery failures out of the 22 flights in drag and OSL, that is 14%, almost three times what is expected!

Like the time in VC#5 when the 10% chance of misfire happened three times in a row to one guy? Or when two other people got it twice in a row? Chan still won't let me forget how badly he got screwed by the random misfires.

Has anyone else bothered to look at running competition settings at different descent resolutions?

I've never looked at the descent resolutions, but I have played with the sample rate during ascent. On lightweight rockets which are ridiculously overpowered, the default setting of 800 samples per second will sometimes start pinwheeling partway through the flight because some of the angular acceleration numbers roll over when they get too high. Increasing the sample rate to 2000 samples/sec or more will often stabilize the simulation.

Originally posted by EMRR
...we need to all encourage Bruce Levison to host and judge a contest.

I'll vote for that. I'd be very interested in seeing what the RockSim Master could inflict upon us. Want to give it a try, Bruce?

 

[teflonrocketry1]

The timing for me to judge a contest is kind of bad right now. Aside from recovering from some serious health problems; I am involved with TARC, constructing GSE for my NAR section (8 pad multi-launcher and controller), being secretary of my NAR section (I get to write a Newsletter), and writing the last two parts of a 4 part RockSim article. At work I have over $1G in new Mass Spectrometry equipment to get installed and qualified. On top of all that, my main PC is six years old and starting to show its age, it refuses to allow me to run 2D flight profiles in RockSim!

I have some ideas of what to do for a competition that will put RockSim through its paces and take everyone into a realm of flight simulations that RockSim is rarely used for.

Bruce S. Levison, NAR #69055

 

[reduc]

Congratulations to the winners! I liked the contest. It helped me to learn about RockSim. I hope to be able to participate in the next one.

 

[chanstevens]

Originally posted by teflonrocketry1

The recovery failures were set to the 5% level, yet Chan mentions three DQ'd recovery failures out of the 22 flights in drag and OSL, that is 14%, almost three times what is expected!

Bruce S. Levison, NAR #69055

Yes, there were 3 failures in the 22 OSL and drag events, but there were zero (maybe 1?) failures in the other events, so overall failures amounted to 3 out of 86 flights. Much more aligned with the 5% rate. I was simply expressing my disappointment that it "randomly" nailed folks in the safe events. Most competitors would accept losing one on a duration flight, but not on OSL.