Vrc-xii Rocket Camp!!!

[n3tjm]

You asked for it, so here it is! A taste of what to expect for the next EMRR Virtual Rocket Challenge!

Event 1 – Design a rocket to go as high as possible with an Estes C6-7 motor.

Even 2 – Design a rocket to go reach highest velocity possible using commercial motors. Multistage allowed for up to three stage. Must used approved motors.

Event 3 – You are issues a FlisKits Flea rocket kit which will be launched twice. You are to design two custom made motors to meet the following two requirements. First event you looking for maximum altitude. Second looking for Max velocity at burnout. Winner of this event will receive a special gift from FlisKits Inc.

Event 4 - Design a rocket to loft a standard Astrocam camera to take a single forward view picture of a rival camp. Your target is 1,200 feet upwind from the launch site, and you want the nose of the rocket to be aimed at that point. The rocket will be launched in the middle of our campground, where the borders are located 500 feet either way. Failure of landing the camera back on our campground will result in a treed or captured rocket, which will result in a DQ. Failure to capture a picture of the target will result in a DQ. 2D Flight Profile will be used to determine this. You can use custom motors or motors from the approved list.

Event 5 - Design a rocket to launch a standard marshmallow and land it as close to the campfire as possible with a safe landing. Our campfire is located 300 feet downwind from the launch site. Do not overshoot the field (remember the border is 500 ft from the launch site). Your Choice of motors can be used. Custom made motors allowed using custom made motor rules.

Official Rules, list of allowed motors, and associated Rocksim files will be posted with the official EMRR update (hoping it will be the next one, however, there are a few small details to work out )

 

[PunkRocketScience]

Oh, man... I gotta go get out my bug spray, sleeping bag and hiking boots! This is gonna be great!

How the heck are you going to do event #4? What is the angle of view for an Astrocam? Or am I overthinking this and the nose just has to be pointed in the general direction of the target?

 

[n3tjm]

Originally posted by PunkRocketScience
How the heck are you going to do event #4? What is the angle of view for an Astrocam? Or am I overthinking this and the nose just has to be pointed in the general direction of the target?

That was the hardest part to figure out. I will use the 2D Flight profile tool, and a straight line will be projected from the centerline of the rocket. I would like the Goal to be to get the straight line closest to the target. I don't think rocksim gives the angle of deployment. If that was the case, simple math will do this. Still working on some of the details for this event. Still thinking on the angle of view. Might make that a fixed distance regardless of altitude.

 

[n3tjm]

And this is how I plan to check it... any comments and suggestions are welcomed.

 

[PunkRocketScience]

That looks pretty reasonable... Just kinda labor intensive...

I've never dinked around with making my own motor files. This should be interesting!

 

[BobCox]

. Oops. Pressed "Send" too soon.

 

[BobCox]

Originally posted by n3tjm
And this is how I plan to check it... any comments and suggestions are welcomed.

This looks like a really fun, challenging, and realistic event. It also looks like a lot of work for the judge. I see at least three potential problems with that approach:

1) As Todd pointed out, it is labor intensive for the judge. In order of increasing work:
(a)Simulation Summary Information: (Max Alt, Max Vel, Max Accel, Vel @ Deployment...) All flights summarized in table form.
(b) Simulation Results: (Takeoff Time, Landing Time, Landing Distance, Landing Speed...) Requires clicking on each flight, then scanning through the log to find the parameter of interest.
(c) 2D Flight Profile: Requires re-running each flight, then single-stepping near the point of interest. This is a lot of work.

2) A bigger problem is that the 2-D flight profile is not reproducible. Clicking on the 2D flight profile button after a completed does not show the detailed information for the completed flight; instead it simulates a new flight with the same starting conditions. The results of the re-flight might be significantly different than the original. I have seen cases where the first flight came down nice and straight and landed within 50 feet of the pad.That same flight in 2D profile caught two thermals and drifted half a mile or more.

This has other implications. If the judge ever needs to go back and review a flight to make sure that it was correct (e.g. were the flying conditions the same as the contestants specified, or were the flight results copied correctly onto the scoring sheet), the simulation will re-run and generate different answers.

3) The angle of the rocket on the 2D flight profile is not exact. The rendering program uses a limited number of sprites at fixed angular spacing. With a small number of sprites , the angular resolution is very coarse. With a larger number of sprites, the simulation runs slower.

If you decide you still want to use the 2D flight profile, here is a way to get the angle of deployment using a numerical method instead of your graphical method.

Clicking on the "Details>>" button will show all the detailed flight information. The Flight Angle is on the 23rd line. It starts out at 90 degrees at takeoff, then gradually changes during the flight. At ejection, it instantly switches back to 90 degrees. Back up one step and it will show the angle that the camera took the picture. If you combine that angle with the Altitude (line 15) and Range (line 16) and some simple trigonometry, you can tell whether the target is within the field of view as well as the distance from the camera to the target.

My suggestion for scoring: Highest score goes to the photo where the camera is closest to the target (hence giving the highest resolution picture). Zero points if the target is not within the field of view. Zero points if the rocket does not land in your own campground.

If you are interested, I will work out the trig and give you the formulas.

----

There may be a large number of zero scores on this event. Maybe consider this: If the flight fails to capture a valid photo, allow re-flights until a valid photo is captured or the rocket is lost out of bounds.

 

[BobCox]

Originally posted by n3tjm
Event 3 – You are issues a FlisKits Flea rocket kit which will be launched twice. You are to design two custom made motors to meet the following two requirements.

Interesting new twist, since none of the VRC's have ever involved custom motors. I'm interested in how you are going to do this. One issue is checking the technical limitations (how much fuel, what specific impulse, timing, etc.). The other is just the sheer logistics for the judge. Adding motors to the library is more complicated than adding a rocket model. This could be a lot of work for the judges (and possibly the contestants).

 

[n3tjm]

Originally posted by BobCox
This looks like a really fun, challenging, and realistic event. It also looks like a lot of work for the judge.....

Clicking on the "Details>>" button will show all the detailed flight information. The Flight Angle is on the 23rd line. It starts out at 90 degrees at takeoff, then gradually changes during the flight. At ejection, it instantly switches back to 90 degrees. Back up one step and it will show the angle that the camera took the picture. If you combine that angle with the Altitude (line 15) and Range (line 16) and some simple trigonometry, you can tell whether the target is within the field of view as well as the distance from the camera to the target.

My suggestion for scoring: Highest score goes to the photo where the camera is closest to the target (hence giving the highest resolution picture). Zero points if the target is not within the field of view. Zero points if the rocket does not land in your own campground.

If you are interested, I will work out the trig and give you the formulas.

----

There may be a large number of zero scores on this event. Maybe consider this: If the flight fails to capture a valid photo, allow re-flights until a valid photo is captured or the rocket is lost out of bounds.

Exactly what I was looking for! Thanks Bob . With those formula's, an online tool can be developed so contestants and the judge will have an easier way of checking the results. And your mentioned method of scoring is what I wanted, just needed a way to get that info! I was thinking that each person will get three tries. I will take you up on the offer for getting the formulas . I will attempt to do the scripting myself (its been a long time since I done that though). Anyone know the field of view for the astrocam? I was thinking 30 degress, but that my be to shallow.

Originally posted by BobCox
Interesting new twist, since none of the VRC's have ever involved custom motors. I'm interested in how you are going to do this. One issue is checking the technical limitations (how much fuel, what specific impulse, timing, etc.). The other is just the sheer logistics for the judge. Adding motors to the library is more complicated than adding a rocket model. This could be a lot of work for the judges (and possibly the contestants).

Exactly! There will be a chart of what impulses are allowed for each allowed motor case size. That way, to quote EMRR, you can't put a M in a 13x45mm motor . Adding a motor file to rocksim is actually not that complicated. There is a minimum burn time limit (no max burn time, but the min velocity rule covers that... not enough thrust will yeild a non safe flight).

This contest will run for a while, giving plenty of time to really tweak your models and motors.

Nobody noticed the last sentence in the Flea event yet?

The Challenge of running a VRC is coming up with something new. Being the twelfth VRC, a lot of idea have been used already .

 

[BobCox]

Originally posted by n3tjm
Exactly what I was looking for! Thanks Bob . With those formula's, an online tool can be developed so contestants and the judge will have an easier way of checking the results. And your mentioned method of scoring is what I wanted, just needed a way to get that info! I was thinking that each person will get three tries. I will take you up on the offer for getting the formulas . I will attempt to do the scripting myself (its been a long time since I done that though).

I'll try to get you the formula tomorrow when my brain is a little fresher. The formula isn't that hard, but I want to be sure that I handle all the signs and 90 degree offset correctly.

Originally posted by n3tjm
Anyone know the field of view for the astrocam? I was thinking 30 degress, but that my be to shallow.

According to this article, the formula for field of view is
angle = 2 * atan ( d / (2*f)),
where d is the size of the film negative and f is the focal length of the lens. The negative for 110 film is 13 x 17 mm, which gives a diagonal distance of 21.4 mm. According to page 44 of this Estes Educator Curriculum Guide, the focal length of the AstroCam is 30.394mm. Plugging these numbers into the formula, the fields of view for the Astrocam are
Vertical: 13mm --> 24.1 degrees
Horizontal: 17mm --> 31.2 degrees
Diagonal: 21.4mm --> 38.8 degrees

So you could arbitrarily pick any number between 24 and 38 degrees, depending on the orientation of the camera and width of the target area.

Adding a motor file to rocksim is actually not that complicated.

You are right, it's not that difficult to add a motor. It may get tedious adding dozens of motors, one at a time.

Exactly! There will be a chart of what impulses are allowed for each allowed motor case size. That way, to quote EMRR, you can't put a M in a 13x45mm motor . ... There is a minimum burn time limit (no max burn time, but the min velocity rule covers that... not enough thrust will yeild a non safe flight).

I'll be interested to see the details on this.

This contest will run for a while, giving plenty of time to really tweak your models and motors.

Plenty of time to procrastinate.

Nobody noticed the last sentence in the Flea event yet?

Looks like product placement has entered the Virtual Rocket Contest arena. Sounds good to me!

The Challenge of running a VRC is coming up with something new. Being the twelfth VRC, a lot of idea have been used already .

I am amazed that you came up with so many clever new events. Then you went and used them all up on one contest. Thanks for making it hard for future judges.:kill:

 

[n3tjm]

Originally posted by BobCox
I'll try to get you the formula tomorrow when my brain is a little fresher. The formula isn't that hard, but I want to be sure that I handle all the signs and 90 degree offset correctly..... So you could arbitrarily pick any number between 24 and 38 degrees, depending on the orientation of the camera and width of the target area.

For simplicity I am just going use 38 degrees.

Originally posted by BobCox


You are right, it's not that difficult to add a motor. It may get tedious adding dozens of motors, one at a time.

All the custom motors can be placed in one engine file per user . Now handling several engine files is my problem

Originally posted by BobCox

I'll be interested to see the details on this.

Motor SizeTotal Impulse (newtons) Allowed Sizes
1/4A 0.32 - 0.625 13x45mm
1/2A 0.63-1.25 13x45mm, 18x70mm
A 1.26 - 2.5 13x45mm, 18x70mm
B 2.6 – 5.0 18x70mm
C 5.1 – 10.0 18x70mm, 24x70mm
D 10.1 - 20.0 24x70mm
E 20.1 - 30.0 (95mm limit) 24x95mm

And two simple formulas that I came up with to calculate propellant and motor weight:

Propellant weight = total impulse in grams (ie a 10 n/s will have 10 grams of propellant)

Initial Mass = twice the total impulse in grams (ie a 10 n/s motor will weigh 20 grams)

Originally posted by BobCox

Plenty of time to procrastinate.

Thats what most people hate about you Bob! They spend two months fine tuning their entry, and then you start it two days before the deadline... and still leave them in the dust! :kill:

Originally posted by BobCox

Looks like product placement has entered the Virtual Rocket Contest arena. Sounds good to me!

Yep! Won't be difficult figuring out what the special prize is either

Originally posted by BobCox

I am amazed that you came up with so many clever new events. Then you went and used them all up on one contest. Thanks for making it hard for future judges.:kill:

Who says I won't be a future judge again Wait till you see what I have in store for next time! Mu ha ha ha ha!

 

[PunkRocketScience]

For the "commercially available motors", are we going to have an updated motor selection with Warp-9 and V-Max motors?

 

[n3tjm]

Originally posted by PunkRocketScience
For the "commercially available motors", are we going to have an updated motor selection with Warp-9 and V-Max motors?

No need. Since Custom motors are limited to:

1/4A 0.32 - 0.625 13x45mm
1/2A 0.63-1.25 13x45mm, 18x70mm
A 1.26 - 2.5 13x45mm, 18x70mm
B 2.6 – 5.0 18x70mm
C 5.1 – 10.0 18x70mm, 24x70mm
D 10.1 - 20.0 24x70mm
E 20.1 - 30.0 (95mm limit) 24x95mm

So are the commercial motors.

This is part of the challenge for the second event!

 

[BobCox]

Originally posted by n3tjm
Thats what most people hate about you Bob!

Talk to my wife and co-workers. They'll tell you plenty of other thing to hate about me.

They spend two months fine tuning their entry, and then you start it two days before the deadline... and still leave them in the dust! :kill:

I don't START two days before the deadline; I just FINISH then. Usually I come up with something half-way decent as soon as the contest starts. Real life usually rears its ugly head then, forcing me to let the VRC entry sit idle for a long time. Then about three days before the deadline, I do a frantic burst of activity to fine-tune my early work, and submit it to the judge with hours to spare. My total time on a VRC entry is typically 30-60 hours.

 

[teflonrocketry1]

For event 3 how many data points are you going to allow in the motor file? Are you going to limit the motor file size? Is there going to be a minimum safe velocity specified off the launch guide for this contest?

For event 5 can you eject the marshmallow from the rocket? It seems to me that they would land safely that way. If this is allowed will you specify the CD to use for the marshmallow?

I hope there are some good prizes for this VRC.

Bruce S. Levison, NAR #69055

 

[n3tjm]

Originally posted by teflonrocketry1
For event 3 how many data points are you going to allow in the motor file? Are you going to limit the motor file size? Is there going to be a minimum safe velocity specified off the launch guide for this contest?

For event 5 can you eject the marshmallow from the rocket? It seems to me that they would land safely that way. If this is allowed will you specify the CD to use for the marshmallow?

I hope there are some good prizes for this VRC.

Bruce S. Levison, NAR #69055

I didn't post the complete list of rules yet for two reasons. Contest does not officially start until its posted on EMRR, and I wanted to see what kind of questions come up. I wanted to see if there was anything I did not think of.

Have not considered how many data points should be allowed. Have to give this some thought.

What do you mean by motor file size?

There is a minimum velocity at launch rod departure and during motor burn.

Marshmallows, as harmless as the are, must stay with the rocket. Tracking a marshmallow fall versus the rockets can be tricky

No idea what the prizes will be, that part of the job is done by EMRR (although I am responsible for the special prize in the flea event ). I do hope that there will be some cool prizes though, cool enough to make all of this work worth it

 

[teflonrocketry1]

Originally posted by n3tjm
Have not considered how many data points should be allowed. Have to give this some thought.

What do you mean by motor file size?

What if I create a 2Gb motor file. Can you even accept files that large via your e-mail account? Will your computer run a motor file that size in RockSim for you?

Bruce S. Levison, NAR #69055

 

[chanstevens]

One thing I wound up doing working around this was to consider the initial sim a throwaway, and the sim results from the 2D plot were used as the official ones. That way the same flight is used for all metrics, albeit not the first one.

The only exception was Bob's entry, which I simmed 167 times trying to cherry pick a thermal that would DQ him. He always seemed to catch a reversal of wind direction blowing him back in the park. Probably slipped a virus in there somewhere to make the host's Rocksim favor anything from his IPC.

I say the next contest involves a payload again--this time a monkey...

 

[n3tjm]

Originally posted by teflonrocketry1
What if I create a 2Gb motor file. Can you even accept files that large via your e-mail account? Will your computer run a motor file that size in RockSim for you?

Bruce S. Levison, NAR #69055

Kinda hard making a 2 GB motor file . I don't think I will have an issue with any motor file e-mailed to me. I also decided on the limits for each custom motors datapoints.

Originally posted by teflonrocketry1

One thing I wound up doing working around this was to consider the initial sim a throwaway, and the sim results from the 2D plot were used as the official ones. That way the same flight is used for all metrics, albeit not the first one.

That is exactly how I plan to do it. The event will be based off the calculations from the 2D profiler. I am working on a javascript page so everyone can calculate the picture taken with the Astrocam event.

 

[PunkRocketScience]

For event #3, are you going to use the Fliskit Flea file that is posted on EMRR or are you going to create a new one for the contest?

And looking at the motor chart... Are you going to allow the 18mm AT D motors?

 

[n3tjm]

Originally posted by PunkRocketScience
For event #3, are you going to use the Fliskit Flea file that is posted on EMRR or are you going to create a new one for the contest?

It will be a modified version of the flea file on emrr. You will be able to download the file from the contest page once its posted.

Originally posted by PunkRocketScience
And looking at the motor chart... Are you going to allow the 18mm AT D motors?

No. This event is based on black powder motors only.

 

[PunkRocketScience]

Bummer....looks like the VRC didn't make it for this update for EMRR... Another couple of weeks?

 

[n3tjm]

I guess Nick needed more time to get the site written for it. This also gives me more time to finish up Event 4. I am working on the javascript, and I want to have a page that explains how to get the data from the simulator and how to use the javascript. So, on Feb 1st, when Nick has it up, that part will be ready to .

 

[EMRR]

I'm working to have this one all ready for Feb 1st start.

Doug, from this, you can develop a FAQ to attach to the bottom of the contest page, and I will link to this thread.

Thanks,
Nick

 

[n3tjm]

Ok, been doing my homework with this contest! I worked hard putting the final details of event 4 together (and writing the javascript program where you and I can check the results). I also added another twist to Event 5!

What I need from you guys is go over all these events, and let me know any additional questions you have. I need them to come up with the FAQ for this contest.

Here is the finialized Event 4 and 5:

Event 4 - Spy on the Rivals

Design a rocket to loft a standard Astrocam camera to take a single forward view picture of a rival camp. Your target is 1,200 feet upwind from the launch site, and you want the nose of the rocket to be aimed at that point. The rocket will be launched in the middle of our campground, where the borders are located 500 feet either way. Failure of landing the camera back on our campground will result in a treed or captured rocket, which will result in a DQ. Failure to capture a picture of the target will result in a DQ. Highest score goes to the photo where the camera is closest line of sight to the target (hence giving the highest quality picture). Flightsim 2D Flight Profile and our Picture Result calculator will be used to determine this.

- You can use custom motors or motors from the approved list.
- Clustering is allowed for this event.
- Must use this file for the Astrocam camera: Astrocam.rkt.
- Modifications to this file is not allowed.
- Field of view of the Astrocam is 38 degrees.
- Please Submit RS file, motor selections, and launch settings
- Custom motors are allowed.
- DQ Conditions:
- Min Velocity and Altitude.
- Recovery Speed.
- Landing out of bounds.
- Failure of capturing picture.

Note: Due to the fact that the 2D profiler may come up with different results than the initial sim, the sim results from the 2D profiler will be the official results.

Event 5 - Marshmallow Roast -

Design a rocket to launch a standard marshmallow and land it as close to the campfire as possible without landing in it! Our campfire is located 300 (+-2) feet downwind from the launch site. Do not overshoot the field (remember the border is 500 ft from the launch site). Marshmallow is 10 grams and is 1.125” long and 1.25” in diameter and must be enclosed in a payload area during the entire flight and recovery.

- Clustering is allowed.
- Your Choice of motors can be used.
- Custom made motors are allowed.
- Please Submit RS file, motor selections, and launch settings
- DQ Conditions:
- Min Velocity and Altitude.
- Recovery Speed.
- Landing out of bounds.
- Landing in the campfire.

 

[BobCox]

Dough,
Big question for all events: What are the wind conditions?

Highest score goes to the photo where the camera is closest line of sight to the target (hence giving the highest quality picture).

As I understand it, the formula will be:
1) Use 2D profile to determine position and nose pointing angle at ejection.
2) Use special calculator to determine angle from rocket to target.
3) Angular error = nose pointing angle - angle from rocket to target.
4) If abs(angular error) > 19 degrees, DQ.
5) If abs(landing distance) > 500 feet, DQ.
6) High score = smallest abs(angular error).

The way it was described before, steps 1-5 were the same, but the score would be based on the distance between the target at the rocket at ejection, with a closer distance giving a higher resolution picture and thus a higher score.

I found that it was fairly easy to get the camera within +/- 19 degrees of the target. The more challenging part was doing so as close to the target as possible.

As an extreme case, imagine that we boost the camera all the way to the moon, then point it straight down and take the picture. The target will be within a fraction of a degree from the center of the picture, but it will be only a tiny speck on the negative. With the smallest-angle scoring criteria, that would be the winner.

The closest-distance criteria, on the other hand, requires the contestant to lob the rocket over the enemy camp, eject as close as possible to the target, and then drift back into our own camp for recovery. Using another extreme example, if we used a monstrous parachute that drifted 1000 feet for every 1 foot of descent, I could eject 1.2 feet above the target and drift right back to the pad. From that close, the picture would have great resolution, even if it was not exactly centered in the frame.


The best strategy lies somewhere between these two extremes.

I think you should switch back to the distance criteria for scoring.

 

[PunkRocketScience]

Okay... Here's a suggestion that would have saved me in the last VRC... How about not referring to targets in the "upwind" and "downwind" fashion and using the same units as Rocksim... + / - ? That way there will be no confusion as to which is which!

Also.... I think I missed something... Are we going back to using the 2D profile for targeting? I thought Bob tracked down the numerical indicator of the flight angle in the data file that was going to be used... To me that seems like it'd be a more precise way to judge the event!

And besides...after several flights I'll get confused by having too many Sharpie lines on my monitor to even see the flight data...

 

[BobCox]

Originally posted by PunkRocketScience
... Are we going back to using the 2D profile for targeting? I thought Bob tracked down the numerical indicator of the flight angle in the data file that was going to be used... To me that seems like it'd be a more precise way to judge the event!

And besides...after several flights I'll get confused by having too many Sharpie lines on my monitor to even see the flight data...

What I came up with was a way to use numbers from the Details tab of the 2D profile to calculate the relevant angles and distances, instead of relying on estimates from the 2D profile graphics. It is still requires the judge to manually type numbers from the RockSim display into a calculator of some sort.

And besides...after several flights I'll get confused by having too many Sharpie lines on my monitor to even see the flight data...

Once that happens, you can always cover them up with White-Out.

 

[n3tjm]

Originally posted by BobCox
Dough,
Big question for all events: What are the wind conditions?

Using another extreme example, if we used a monstrous parachute that drifted 1000 feet for every 1 foot of descent, I could eject 1.2 feet above the target and drift right back to the pad. From that close, the picture would have great resolution, even if it was not exactly centered in the frame.


The best strategy lies somewhere between these two extremes.

I think you should switch back to the distance criteria for scoring.

Wind Conditions are Top Secret atm . You will see that on the first.

There is a maximum parachute size, so I am not sure the extreme would be possible.

What if I did both distance and center? How should I score that? Highest score for centered, and highest score for Distance?

 

[BobCox]

Originally posted by n3tjm
Wind Conditions are Top Secret atm . You will see that on the first.

That's fine, as long as you let us know what it is.

There is a maximum parachute size, so I am not sure the extreme would be possible.

Since we are not allowed to modify the AstroCam.rkt file, we won't be able to change the parachute size anyway.
BTW, that is a good idea to have everybody use the same .rkt file; it's one less variable that you will have to deal with as a judge. With so many different events, rockets, and engine files, you are going to have your work cut out for you.

What if I did both distance and center? How should I score that? Highest score for centered, and highest score for Distance?

You'd just be making more work for yourself by having two different criteria. On several previous contests, having two criteria for the same event (e.g. lowest deployment and slowest deployment) can result in tie scores on an event. It's easier to just have a single criterion.