Formula-R Egg Race (Need HELP URGENT!!)

limchee · Post by **limchee** » Wed Mar 07, 2007 5:55 am

Objective

Design and build a "vehicle" that is powered only by one standard rubber band to transport a raw chicken egg the greatest possible horizontal displacement without breaking the egg.

Rules

1. The vehicle must be constructed from basic components. The components, however, cannot be parts from toy cars. Otherwise, there is no restriction on the material that could be used for the vehicle.

2. The vehicle must not have any parts that can rotate. The egg must not rotate also while the vehicle is moving and must remain on the vehicle so you might want to use a "seatbelt" for the egg.

3. You must design and construct your own catapult using only one standard rubber band. The rubber band may be cut but it may not be treated with chemicals or heated or cooled.

4. The vehicle must be launched using a catapult.

5. The catapult with the rubber band must be anchored to the ground at the starting point.

6. You are not allowed to use any lubricant in the form of liquid (including ice) or powder for test-runs.

7. Displacement will be measured relative to the centre point of the egg.

anyone can help me? need it urgently... and my brain is still empty now!! T_T

deleted-71588 · Post by **deleted-71588** » Wed Mar 07, 2007 8:06 am

Have you thought about the problem and broken it down into simpler problems yet?
What is the surface that you are racing over? The rules say "ground" but that could be anything from grass to sand to clay to concrete or asphalt.

limchee · Post by **limchee** » Fri Mar 09, 2007 5:39 am

i know i hav to protect the egg... and im thinking about using a catapult powered by a rubber band to launch the vehicle into the air... hoping that the egg wont break.

problem is.. if i let it slide on the ground.. it will hav friction and slow the vehicle down...

i thought of using airfoil as well....

and the floor is concrete....

deleted-71576 · Post by **deleted-71576** » Fri Mar 09, 2007 7:01 am

Looking at the rules you posted, I would think that a catapult would be disqualified (doesn't stay on the vehicle).

deleted-71576 · Post by **deleted-71576** » Fri Mar 09, 2007 7:06 am

Whoops. Ignore my last post. I wish there was an edit button.

So your vehicle is really just what the egg travels in. The catapult stays put.

Interesting project.

Break it down into several different projects. Do a search on egg drop projects to learn how to protect an egg from impact. Then look up how to design a catapult.

You may find that the more protected the egg is, the less far it will travel -- this will be what separates the projects, as the force developed by all the catapults since they have to use just 1 rubber band should be relatively similar.

limchee · Post by **limchee** » Fri Mar 09, 2007 7:06 am

the catapult is used to launch the vehicle... that's it i think
and the rubber bands are normal rubber bands...

deleted-71588 · Post by **deleted-71588** » Fri Mar 09, 2007 7:56 am

i know i hav to protect the egg... and im thinking about using a catapult powered by a rubber band to launch the vehicle into the air... hoping that the egg wont break.

problem is.. if i let it slide on the ground.. it will hav friction and slow the vehicle down...

Think about the force needed to "lift" an object (vehicle with egg) compared to the energy needed to push the object along a concrete floor.

I'm thinking you can probably come up with a vehicle where the coefficient of friction is less than 1 (even without using things that rotate). With the lift problem, unless you use a lighter than air vehicle, you are stuck with a coefficient of at least 1. You can't turn off gravity, so F = ma {Force = mass times acceleration}, which for lift, acceleration is the gravitational constant "g" or 1g. Since you also need some forward vector, there will be some small frictional component involved in moving the vehicle through the air so you are > 1g.

Interesting, the rules you posted didn't preclude lighter than air vehicles. If you want to go for something exotic, an aerodynamic lighter than air vehicle might be an extreme challenge and expensive in terms of materials and time. How much time calandar wise do you have and how many hours do you think you can devote to this project? I'm guessing you won't have the time to figure out how to contain helium in a light weight areodynamic vehicle that will go straight most of the time.

I'm guessing the most likely winner will be somebody who figures out how to create a light weight low friction sled who figures out how to keep it upright and get it to go straight most of the time and is lucky enough to have it behave in the actual trials.

deleted-71576 · Post by **deleted-71576** » Fri Mar 09, 2007 8:28 am

How about a helium balloon attached to the egg, with the catapult launch simply being releasing the balloon?

You could make a simple propeller to get the balloon moving via the rubber band. Might be nice to have the distance be miles instead of feet. Hard to prove that the egg survived intact, though.

Wow, Craig. "Lighter than air vehicle". Nice thought.

How about something as simple as an egg in bubble wrap? Enclose this in a mylar balloon (cut one open, deposit the "vehicle" then tape closed). I don't see a need to make it go straight. You just want it to go in any direction. The more gentle breeze, the better.

deleted-71588 · Post by **deleted-71588** » Fri Mar 09, 2007 8:48 am

How about a helium balloon attached to the egg?

Rules state you only have one "standard" rubberband to use to propel your vehicle. Predicting what the wind conditions might be several weeks ahead on the trial date might be a problem. Using a breeze might also be disqualified. The course also might be dictated to go up wind and a balloon would go down wind.

Even if this were indoors, the heating, cooling, and ventilation system will generate air currents.

Simple balloons have a lot of "drag".

A lot to consider with this kind of approach, but limchee thought about an "airfoil" shape and I was just offering a combine it with something lighter than air to overcome the 1g lift issue...

limchee · Post by **limchee** » Fri Mar 09, 2007 9:01 am

but where can i get "something which lighter than air"
even if i hav the "something", how do i put it into my vehicle?

by the way... the test run is in indoor...

deleted-71576 · Post by **deleted-71576** » Fri Mar 09, 2007 9:11 am

Craig_Bridge wrote:
How about a helium balloon attached to the egg?
Rules state you only have one "standard" rubberband to use to propel your vehicle. Predicting what the wind conditions might be several weeks ahead on the trial date might be a problem. Using a breeze might also be disqualified. The course also might be dictated to go up wind and a balloon would go down wind.

Even if this were indoors, the heating, cooling, and ventilation system will generate air currents.

Simple balloons have a lot of "drag".

A lot to consider with this kind of approach, but limchee thought about an "airfoil" shape and I was just offering a combine it with something lighter than air to overcome the 1g lift issue...

I'm not sure if those are all the rules (which might eliminate the balloon), but I don't think it matters which way the wind blows, just so long as it blows. Any heading where horizontal motion occurs will count as displacement from the origin. Indoor air currents as well. Just so long as the balloon floats away from the origin. I don't think any kind of rudder device is necessary at all.

At MIT, my roommate won one of the first large scale paper airplane competitions by crumpling up a piece of paper and throwing it as hard as he could. Beat all the aerodynamic shapes/planes in total distance. (He had a cannon for an arm). He just was smart enough to think out of the box. Needless to say, they changed the rules the next year.

Anyway, limchee, Craig and I are just passing time debating one approach. What have you been thinking of?

deleted-71588 · Post by **deleted-71588** » Fri Mar 09, 2007 9:15 am

but where can i get "something which lighter than air"
even if i hav the "something", how do i put it into my vehicle?

You are asking great questions.

zzzdoc mentioned Helium and balloon. Helium is an inert gas that is lighter than air so in its uncompressed state, it would be considered safe to work with.

Containing it and putting it into your vehicle is a problem and a challenge.

This project is all about challenges and problem solving and you have to be the major part of that because it is your project. Part of the challenge is to pick the problems you want to deal with and eliminate the ones you don't.

As Alan said, what are you thinking?

Louise · Post by **Louise** » Fri Mar 09, 2007 10:17 am

Craig_Bridge wrote:
but where can i get "something which lighter than air"
even if i hav the "something", how do i put it into my vehicle?
You are asking great questions.

zzzdoc mentioned Helium and balloon. Helium is an inert gas that is lighter than air so in its uncompressed state, it would be considered safe to work with.

Containing it and putting it into your vehicle is a problem and a challenge.

This project is all about challenges and problem solving and you have to be the major part of that because it is your project. Part of the challenge is to pick the problems you want to deal with and eliminate the ones you don't.

As Alan said, what are you thinking?

I'm not sure helium would be considered a "basic component". That is a pretty vague criteria, but it would be a shame if a lot of time and effort went in to a creative solution, which then got disqualified for being too creative.

I would double check with the teacher that this is allowed before you invest too much time in the design. My guess is that the teacher is interested in how aerodynamic you can make a protective capsule, and anything else is outside the scope of the project.

Louise

Louise