Rotor Egg Drop B

Bozongle
Member
Member
Posts: 76
Joined: Sun Jan 20, 2013 8:41 pm
Division: B
State: IN
Contact:

Re: Rotor Egg Drop B

Postby Bozongle » Mon Apr 28, 2014 7:34 pm

I concur with all of your points, especially some your comments regarding stability.
Based off my experience (bad ones), I've realized that although greater surface area is a good thing and can get you slower times, it also requires you to focus A LOT more on stability. As at this point, there is so many forces involved in slowing down your rotor that a small bit of instability will ruin your drop. At State for Indiana, that got me. I had a consistent rotor that got at least ~3.5 seconds from around 4.6-4.7m. I was set. I saw it swayed a little but didn't really mind the instability. BIG MISTAKE. At State, it was a drop of about 11-11.5 meters.

When I dropped it, all went well at first, but then around 6 meters down, things went crazy. My rotor began to sway crazily and about 3 meters from the floor it literally swooped upside down but somehow the egg hit the ground first and survived. My time was 6.2 seconds, but it could easily have gotten 8-9 seconds had it been perfectly stable. Ended up getting 3rd, but I was lucky that I was not tiered and that the egg miraculously survived.

My design utilized 4 rotors, and I will admit I didn't really pay attention to perfecting balance between all 4, thus resulting in instability and finally a terrible drop.

User avatar
Toms_42
Member
Member
Posts: 143
Joined: Sat Nov 17, 2012 2:57 pm
Division: Grad
State: PA
Location: Shady Side Academy HS; Pittsburgh PA
Contact:

Re: Rotor Egg Drop B

Postby Toms_42 » Mon May 05, 2014 3:04 am

Bozongle wrote:I concur with all of your points, especially some your comments regarding stability.
Based off my experience (bad ones), I've realized that although greater surface area is a good thing and can get you slower times, it also requires you to focus A LOT more on stability. As at this point, there is so many forces involved in slowing down your rotor that a small bit of instability will ruin your drop. At State for Indiana, that got me. I had a consistent rotor that got at least ~3.5 seconds from around 4.6-4.7m. I was set. I saw it swayed a little but didn't really mind the instability. BIG MISTAKE. At State, it was a drop of about 11-11.5 meters.

When I dropped it, all went well at first, but then around 6 meters down, things went crazy. My rotor began to sway crazily and about 3 meters from the floor it literally swooped upside down but somehow the egg hit the ground first and survived. My time was 6.2 seconds, but it could easily have gotten 8-9 seconds had it been perfectly stable. Ended up getting 3rd, but I was lucky that I was not tiered and that the egg miraculously survived.

My design utilized 4 rotors, and I will admit I didn't really pay attention to perfecting balance between all 4, thus resulting in instability and finally a terrible drop.


It's not really about balancing the blades, it's more about insuring constant pitch and proper stringing. My rotor does not have a very high surface area, but it has a highly tuned pitch and string setup. we have gotten consistant 1-3 placements throughout the ohio invites and states with it.

My "partner" (we didn't work together, we just competed as to who could make the best rotor) chose a different approach that focused on surface area, and most of his builds were unstable.
Image

ckssv07
Admin Emeritus
Admin Emeritus
Posts: 186
Joined: Tue Mar 22, 2011 2:33 pm
Division: C
State: PA
Contact:

Re: Rotor Egg Drop B

Postby ckssv07 » Mon May 05, 2014 11:11 am

Toms_42 wrote:
Bozongle wrote:I concur with all of your points, especially some your comments regarding stability.
Based off my experience (bad ones), I've realized that although greater surface area is a good thing and can get you slower times, it also requires you to focus A LOT more on stability. As at this point, there is so many forces involved in slowing down your rotor that a small bit of instability will ruin your drop. At State for Indiana, that got me. I had a consistent rotor that got at least ~3.5 seconds from around 4.6-4.7m. I was set. I saw it swayed a little but didn't really mind the instability. BIG MISTAKE. At State, it was a drop of about 11-11.5 meters.

When I dropped it, all went well at first, but then around 6 meters down, things went crazy. My rotor began to sway crazily and about 3 meters from the floor it literally swooped upside down but somehow the egg hit the ground first and survived. My time was 6.2 seconds, but it could easily have gotten 8-9 seconds had it been perfectly stable. Ended up getting 3rd, but I was lucky that I was not tiered and that the egg miraculously survived.

My design utilized 4 rotors, and I will admit I didn't really pay attention to perfecting balance between all 4, thus resulting in instability and finally a terrible drop.


It's not really about balancing the blades, it's more about insuring constant pitch and proper stringing. My rotor does not have a very high surface area, but it has a highly tuned pitch and string setup. we have gotten consistant 1-3 placements throughout the ohio invites and states with it.

My "partner" (we didn't work together, we just competed as to who could make the best rotor) chose a different approach that focused on surface area, and most of his builds were unstable.

"Partner" here.
If you build to max dimensions this year, and max out your surface area, it is bound to be unstable, since the pitch of each blade will never be the same. His rotor worked really well for tall drops as it was able to stay stable for the whole drop, but did not really start rotating enough to capitalize on small drops. My approach worked really well on lower drops, getting over 5.2 seconds off of 5 meters, but became unstable after about 7 meters leaving it rather useless for higher drops. It is all about tuning your rotor for the circumstances in which you will be dropping, and stringing them carefully to take out as much instability as you can.

User avatar
Toms_42
Member
Member
Posts: 143
Joined: Sat Nov 17, 2012 2:57 pm
Division: Grad
State: PA
Location: Shady Side Academy HS; Pittsburgh PA
Contact:

Re: Rotor Egg Drop B

Postby Toms_42 » Mon May 19, 2014 1:04 pm

Congrats to everyone who did rotor egg drop this year! Does anyone know the winning time? I got 4th (really close to a $3k scholarship arggg) with something between 8.2 and 8.6 (I didn't time it, but my friend took video)
I noticed a lot of people hit the wall (including Daniel Wright.) I got lucky, ours narrowly avoided it despite being 80 something cm wide at its largest point.
Image

User avatar
Adi1008
Moderator
Moderator
Posts: 414
Joined: Fri Dec 06, 2013 9:56 pm
Division: C
State: TX
Location: Austin, Texas
Contact:

Re: Rotor Egg Drop B

Postby Adi1008 » Tue May 20, 2014 8:41 pm

Toms_42 wrote:Congrats to everyone who did rotor egg drop this year! Does anyone know the winning time? I got 4th (really close to a $3k scholarship arggg) with something between 8.2 and 8.6 (I didn't time it, but my friend took video)
I noticed a lot of people hit the wall (including Daniel Wright.) I got lucky, ours narrowly avoided it despite being 80 something cm wide at its largest point.


I personally counted without any sort of timer (as I dropped it) around 8.5 and my partner counted around 8 seconds, but people timing in the audience (mainly parents and other students) told me that my partner and I got 9.0-9.5. I timed our device from a video my friend took and got 9.07. However, I got sixth, so I don't know if we can use these times as a benchmark, as you said you got 8.2-8.6 and got fourth (congratulations). I know Riverwood got 11.3 seconds (that's what the guy on the event said and I trust him).

One thing I noticed is that at nationals, imo, it's better to have a stable rotor rather than one that would necessarily get extremely good times (of course, you want it to get good times in addition to it being stable, but I think there has to be a balance). The drops are usually pretty high (e.g., from four floors), so there is going to be more time for small things, such as wind gusts and variance in the blades of your device, to significantly impact the performance of the device in comparison to a drop from just one floor. If you tape a couple of papers to a paper towel roll so that it would spin and tie an egg to it and drop it and get tier two, you would have done better than someone who got 8 seconds and tier three because their device was unstable over large drops. I know that my partner and I worked a lot to ensure that ours was extremely stable, and it wasn't a problem for us this year (our school got 43rd last year from it being unstable :cry: ).
Last edited by Adi1008 on Sat May 24, 2014 3:00 pm, edited 1 time in total.
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

User avatar
Toms_42
Member
Member
Posts: 143
Joined: Sat Nov 17, 2012 2:57 pm
Division: Grad
State: PA
Location: Shady Side Academy HS; Pittsburgh PA
Contact:

Re: Rotor Egg Drop B

Postby Toms_42 » Wed May 21, 2014 1:59 am

Adi1008 wrote:
Toms_42 wrote:Congrats to everyone who did rotor egg drop this year! Does anyone know the winning time? I got 4th (really close to a $3k scholarship arggg) with something between 8.2 and 8.6 (I didn't time it, but my friend took video)
I noticed a lot of people hit the wall (including Daniel Wright.) I got lucky, ours narrowly avoided it despite being 80 something cm wide at its largest point.


I personally counted without any sort of timer (as I dropped it) around 8.5 and my partner counted around 8 seconds, but people timing in the audience (mainly parents and other students) told me that my partner and I got 9.0-9.5. I timed our device from a video my friend took and got 9.07. However, I got sixth, so I don't know if we can use these times as a benchmark, as you said you got 8.2-8.6 and got fourth (congratulations). I know Riverwood got 11.3 seconds (that's what the guy on the event said).

One thing I noticed is that at nationals, imo, it's better to have a stable rotor rather than one that would necessarily get extremely good times (of course, you want it to get good times in addition to it being stable, but I think there has to be a balance). The drops are usually pretty high (e.g., from four floors), so there is going to be more time for small things, such as wind gusts and variance in the blades of your device, to significantly impact the performance of the device in comparison to a drop from just one floor. If you tape a couple of papers to a paper towel roll so that it would spin and tie an egg to it and drop it and get tier two, you would have done better than someone who got 8 seconds and tier three because their device was unstable over large drops. I know that my partner and I worked a lot to ensure that ours was extremely stable, and it wasn't a problem for us this year (our school got 43rd last year from it being unstable :cry: ).


That is odd that you got an apparently higher time, and the 11.3 is a bit far fetched for my tastes. We took a video of it and analyzed it to find the EXACT fall time. I can't remember off the top of my head, but it was something like 8.5. Also, I would bet that the top times were VERY close, as they were last year, which unfortunately results in a lot of timer error. If this event ever returns they should have cameras or something and have a group of people analyze the videos. Congrats on 6 though!
Image

Bozongle
Member
Member
Posts: 76
Joined: Sun Jan 20, 2013 8:41 pm
Division: B
State: IN
Contact:

Re: Rotor Egg Drop B

Postby Bozongle » Wed May 21, 2014 2:37 am

Adi1008 wrote:
Toms_42 wrote:Congrats to everyone who did rotor egg drop this year! Does anyone know the winning time? I got 4th (really close to a $3k scholarship arggg) with something between 8.2 and 8.6 (I didn't time it, but my friend took video)
I noticed a lot of people hit the wall (including Daniel Wright.) I got lucky, ours narrowly avoided it despite being 80 something cm wide at its largest point.


I personally counted without any sort of timer (as I dropped it) around 8.5 and my partner counted around 8 seconds, but people timing in the audience (mainly parents and other students) told me that my partner and I got 9.0-9.5. I timed our device from a video my friend took and got 9.07. However, I got sixth, so I don't know if we can use these times as a benchmark, as you said you got 8.2-8.6 and got fourth (congratulations). I know Riverwood got 11.3 seconds (that's what the guy on the event said).

One thing I noticed is that at nationals, imo, it's better to have a stable rotor rather than one that would necessarily get extremely good times (of course, you want it to get good times in addition to it being stable, but I think there has to be a balance). The drops are usually pretty high (e.g., from four floors), so there is going to be more time for small things, such as wind gusts and variance in the blades of your device, to significantly impact the performance of the device in comparison to a drop from just one floor. If you tape a couple of papers to a paper towel roll so that it would spin and tie an egg to it and drop it and get tier two, you would have done better than someone who got 8 seconds and tier three because their device was unstable over large drops. I know that my partner and I worked a lot to ensure that ours was extremely stable, and it wasn't a problem for us this year (our school got 43rd last year from it being unstable :cry: ).


Yeah the instability problem got us at nats, we had a decent time but instability ruined it. Tier 3ed, and got 46th place. BUT, the funny thing is we didn't get tiered for an unstable device that hit before the egg hit the ground, we got tiered for building a parachute. Thing is, our device spun perfectly fine, more than enough to be considered a rotor, but to the supervisor apparently our covering was not taut enough to be considered as a rotor (although it spun as if it was a rotor). Unfortunately, my partner decided to let it go rather than appeal and took the device out of impound. I had an event conflict so I couldn't have made the decision.

Anybody got thoughts on this?

User avatar
Adi1008
Moderator
Moderator
Posts: 414
Joined: Fri Dec 06, 2013 9:56 pm
Division: C
State: TX
Location: Austin, Texas
Contact:

Re: Rotor Egg Drop B

Postby Adi1008 » Wed May 21, 2014 2:47 am

Toms_42 wrote:
Adi1008 wrote:
Toms_42 wrote:Congrats to everyone who did rotor egg drop this year! Does anyone know the winning time? I got 4th (really close to a $3k scholarship arggg) with something between 8.2 and 8.6 (I didn't time it, but my friend took video)
I noticed a lot of people hit the wall (including Daniel Wright.) I got lucky, ours narrowly avoided it despite being 80 something cm wide at its largest point.


I personally counted without any sort of timer (as I dropped it) around 8.5 and my partner counted around 8 seconds, but people timing in the audience (mainly parents and other students) told me that my partner and I got 9.0-9.5. I timed our device from a video my friend took and got 9.07. However, I got sixth, so I don't know if we can use these times as a benchmark, as you said you got 8.2-8.6 and got fourth (congratulations). I know Riverwood got 11.3 seconds (that's what the guy on the event said).

One thing I noticed is that at nationals, imo, it's better to have a stable rotor rather than one that would necessarily get extremely good times (of course, you want it to get good times in addition to it being stable, but I think there has to be a balance). The drops are usually pretty high (e.g., from four floors), so there is going to be more time for small things, such as wind gusts and variance in the blades of your device, to significantly impact the performance of the device in comparison to a drop from just one floor. If you tape a couple of papers to a paper towel roll so that it would spin and tie an egg to it and drop it and get tier two, you would have done better than someone who got 8 seconds and tier three because their device was unstable over large drops. I know that my partner and I worked a lot to ensure that ours was extremely stable, and it wasn't a problem for us this year (our school got 43rd last year from it being unstable :cry: ).


That is odd that you got an apparently higher time, and the 11.3 is a bit far fetched for my tastes. We took a video of it and analyzed it to find the EXACT fall time. I can't remember off the top of my head, but it was something like 8.5. Also, I would bet that the top times were VERY close, as they were last year, which unfortunately results in a lot of timer error. If this event ever returns they should have cameras or something and have a group of people analyze the videos. Congrats on 6 though!


I have competed against Riverwood's rotor's for two years now (both of us are in Texas and go to the same invitationals) and I can say that they are every good as they seem (at least in my opinion; I've never beat them). I am not surprised that much at the time they got (last year they got about 9.6 seconds and improvement is expected). While I don't know what the times really are for top 6, I would think they would probably be >8.5 seconds. I remember not knowing exactly when the device hit the ground while I was counting right after I dropped it, but while watching the video, there seemed to be a very audible sound. If I recall correctly (which I probably am not), last year Riverwood won by a relatively large margin and 2-6 were extremely close.

I agree with your thoughts to have a better method of timing, but I personally feel that would be very difficult. Firstly, many rotors would sway from side to side and might even "fall/glide" out of the "zone" that is being used by the cameras/photogates/whatever to measure the time. This may or may not be a problem, but I think it would (don't have experience with this stuff). Another possibility would be attaching a small sensor at the bottom of the cup and having an automated drop. Once a button is pressed to initiate the drop, the timer starts and it stops once the bottom of the cup hits the ground. However, this brings up another problem - what about devices that get tier three or even four because the rotor would hit first - not the cup. We couldn't cover the rotor with a ton of sensors either - the impact could be anywhere and it would be even more impractical. While I would like a way to have the time measurements more accurate, I think it would be very hard to implement and even if it could, it would not be cost effective or even provide a better experience. What if the sensor fails to activate or stop? Would the device be dropped again? Would there be human timers as well, as they do in many youth swimming leagues?

While not perfect, I think the method of timing is acceptable and is fairly efficient.

Bozongle wrote:
Yeah the instability problem got us at nats, we had a decent time but instability ruined it. Tier 3ed, and got 46th place. BUT, the funny thing is we didn't get tiered for an unstable device that hit before the egg hit the ground, we got tiered for building a parachute. Thing is, our device spun perfectly fine, more than enough to be considered a rotor, but to the supervisor apparently our covering was not taut enough to be considered as a rotor (although it spun as if it was a rotor). Unfortunately, my partner decided to let it go rather than appeal and took the device out of impound. I had an event conflict so I couldn't have made the decision.

Anybody got thoughts on this?


Beckendorff got tier three last year because the rotor hit the ground first and got 43rd and had a time of around 8 seconds. Just goes to show that stability is arguably as important as the time your device gets, especially over large drops. As for the parachute decision, I've always thought that if it spun quickly enough, it would be considered a rotor rather than a parachute. I've had many rotors with curved surfaces but this has never been a problem for me as my devices rotate pretty quickly (for stability). However, it is up to the discretion of the ES.
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

User avatar
Supraturtle1324
Member
Member
Posts: 1
Joined: Sun Jun 01, 2014 10:20 pm
Division: B
State: TX
Contact:

Re: Rotor Egg Drop B

Postby Supraturtle1324 » Sun Jun 01, 2014 10:39 pm

Hello, I am the first place winner in Rotor Egg Drop from Riverwood Middle School. I agree that having a stable model is key in this event. My partner and I have built models that have a longer drop time than our national model, but they were not as stable.
Adi1008: Congratulations to your team winning first in the Nation.
2012: 5th Rotor Egg Drop
2013: 1st Rotor Egg Drop, 5th Helicopters
2014: 1st Rotor Egg Drop, 2nd Robo-Cross, 3rd Helicopters, 5th Can't Judge a Powder
Going into Division C!!!!

User avatar
Adi1008
Moderator
Moderator
Posts: 414
Joined: Fri Dec 06, 2013 9:56 pm
Division: C
State: TX
Location: Austin, Texas
Contact:

Re: Rotor Egg Drop B

Postby Adi1008 » Sat Jun 14, 2014 11:18 pm

Supraturtle1324 wrote:Hello, I am the first place winner in Rotor Egg Drop from Riverwood Middle School. I agree that having a stable model is key in this event. My partner and I have built models that have a longer drop time than our national model, but they were not as stable.
Adi1008: Congratulations to your team winning first in the Nation.


Woah, thanks. Congrats to you as well for getting medals in all of your events at nationals and being OP in rotor. Good luck in Division C!
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

watermelonsonnet
Member
Member
Posts: 1
Joined: Mon Aug 11, 2014 4:16 pm
Division: B
State: MD
Contact:

Re: Rotor Egg Drop B

Postby watermelonsonnet » Tue Aug 19, 2014 3:52 pm

If any of you would like a rotor egg drop device to serve as a foundation for further exploration into this event, please visit this link http://rotoreggdrop.blogspot.com/. Since I enjoyed making this device so much, I thought I would spread the knowledge and experience I gained from building and experimenting by creating a manual for other's to follow. Please keep in mind that there's more than just this one way to build a rotor egg drop device. This manual should only serve as a baseline for you to build your findings off of. Have fun experimenting and best of luck!


Return to “2014 Build Events”

Who is online

Users browsing this forum: No registered users and 1 guest