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Phase two of the prototype. The ball went 37 ft and was at a approximately 30* angle. First one to guess (calculate) how fast the wheels were spinning within 50 rpm will receive a prize from the TechTigers.
Discussion
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13-01-2006 22:31
David Guzman
Re: pic: 1251 Prototype v 1.2
Phase two of the prototype. The ball went 37 ft and was at a approximately 30* angle. First one to guess (calculate) how fast the wheels were spinning within 50 rpm will receive a prize from the TechTigers.
Here is video of it.
http://media.putfile.com/Prototype-v12
13-01-2006 22:55
Conor Ryan
Re: pic: 1251 Prototype v 1.2
My Guess is ahh 1050 RPM, I think I'm closer than I originally thought.
13-01-2006 22:59
skimoose
Re: pic: 1251 Prototype v 1.2
I'm not a mechanical guy, so it's hard to pick out those sprocket sizes, but I'll go with about 1665 RPM. 
Nice prototype, remember safety FIRST!
(How about fuse/breaker and at least a switch away from the shooter)
14-01-2006 01:49
sanddrag
Re: pic: 1251 Prototype v 1.2
What kind of accuracy can you get over that range? Can you make 10 in a row into the goal?
14-01-2006 02:33
Jon K.
Re: pic: 1251 Prototype v 1.2
My guess would be around 1800 but its hard to tell becuase of the sprocket sizes, my guess would be the big one is around 40-50 teeth probably maybe even 60 and the small one around 10-20ish maybe....
14-01-2006 13:39
David Guzman
Re: pic: 1251 Prototype v 1.2
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Originally Posted by sanddrag
What kind of accuracy can you get over that range? Can you make 10 in a row into the goal?
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In my opinion it is very accurate.
14-01-2006 17:47
Eric Scheuing
Re: pic: 1251 Prototype v 1.2
Very nice idea. I think it might be a winner.
About 1775 rpm?
14-01-2006 22:01
b-rant
Re: pic: 1251 Prototype v 1.2
I have to say this seems to be the best way to shoot because the 4 wheels help guide the ball to the needed derection and the constant motion allows balls to pass though as fast as need. seems to be going 4m/s? maybe.... so i don't know any calculations for that but......2,329rpms?
14-01-2006 22:29
tkwetzel
Re: pic: 1251 Prototype v 1.2
Well...I finally made it back to Chief Delphi after being away for so long.
The sprocket size should not matter at all to answer their question. They asked how fast the wheels were spinning, not the motors. With an angle and distance you need the size of the wheels and possibly height of the arc of travel to find the rpm of the wheels to launch one of the foam balls that far.
Without calculations I will guess that the wheels are spinning at 1,900 rpm.
14-01-2006 22:43
Andrew Blair
Re: pic: 1251 Prototype v 1.2
The size of the wheel has nothing to do with the RPM of them (Unless you say that their mass slows down the system). If we know the output speed of the Kit gearbox, and we know the ratio to the the wheels, we can, with some error, find the RPM of the wheels. Now, if we were looking for the linear speed from a reference point on the wheel, then wheel size would matter.
14-01-2006 22:47
Tom Bottiglieri
Re: pic: 1251 Prototype v 1.2
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Originally Posted by Andrew Blair
The size of the wheel has nothing to do with the RPM of them (Unless you say that their mass slows down the system). If we know the output speed of the Kit gearbox, and we know the ratio to the the wheels, we can, with some error, find the RPM of the wheels. Now, if we were looking for the linear speed from a reference point on the wheel, then wheel size would matter.
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14-01-2006 23:17
i_am_Doug
Re: pic: 1251 Prototype v 1.2
EDIT: im now guessing your team number ;p 1251.
14-01-2006 23:25
Stephen P
Re: pic: 1251 Prototype v 1.2
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Originally Posted by tkwetzel
Well...I finally made it back to Chief Delphi after being away for so long.
The sprocket size should not matter at all to answer their question. They asked how fast the wheels were spinning, not the motors. With an angle and distance you need the size of the wheels and possibly height of the arc of travel to find the rpm of the wheels to launch one of the foam balls that far. Without calculations I will guess that the wheels are spinning at 1,900 rpm. |
15-01-2006 01:42
tkwetzel
Re: pic: 1251 Prototype v 1.2
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Originally Posted by Stephen P
You couldnt find out the rotational speed from just projectile distance, becausethis would require the assumption that 100% of the wheels energy is translated into the ball (a horrible assumption).
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15-01-2006 12:17
Andrew Blair
Re: pic: 1251 Prototype v 1.2
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Originally Posted by Tom Bottiglieri
Who says the trannies are running at full power?
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15-01-2006 12:19
Andrew Blair
Re: pic: 1251 Prototype v 1.2
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Originally Posted by tkwetzel
That is not true. You could assume whatever efficiency of energy translation you want, but whatever number you use would be an estimate without knowing other information. You also have to estimate a few otehr numbers. But tehy gave you the angle and distance traveled.
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15-01-2006 15:06
SpaceBoy2000
Re: pic: 1251 Prototype v 1.2
Based on my team's prototype, 2885 RPM
EDIT: I'm assumming 8' wheels too there...
EDIT 2: Whoops, forgot to add in sprockets
15-01-2006 15:52
pakrat
Re: pic: 1251 Prototype v 1.2
Well, I dont have a guess, But i will say that thing looks pretty sweet. Have you guys looked at the difference between running 2 spinwheels on each side as opposed to one?
15-01-2006 19:20
David Guzman
Re: pic: 1251 Prototype v 1.2
A couple of more hints.
-The wheels are 8 inches
-We assumed that only 75% of the distance covered by the spinning wheel gets to the ball. We were looking for the speed limit.
It's too easy now. 
Dave
15-01-2006 20:19
nehalita
Re: pic: 1251 Prototype v 1.2
2560 rpm?
Wait... does 37 feet mean 37 feet horizontally?
15-01-2006 20:23
Smithvillefirst
Re: pic: 1251 Prototype v 1.2
From the video sound it sounds as if you need to grease the gearbox ours was the same until it was well greased.
Anthony Peck,
Integration Manager
Team 1806
15-01-2006 21:36
David Guzman
Re: pic: 1251 Prototype v 1.2
The gear boxes are greased but haven't been checked since last year. Most of the noise is coming from the chain.
Yes, 37 ft horizontally.
16-01-2006 11:10
cire
Re: pic: 1251 Prototype v 1.2
Looks like 1269 RPM to me
gear ratio * free speed of kit transmisson
3:1 * 423 rpm = 1269 rpm
edit - I estimated that the larger sprocket was 36T and the smaller one was 12T by looking at the picture.
16-01-2006 12:14
Rick TYler
Re: pic: 1251 Prototype v 1.2
I know I'm coming late to the party, but 1,250 rpm, plus or minus two weeks.
(Bonus if you recognized the obscure movie reference.)
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