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### HELP, NEED TO INTVIEW EXPERT

Posted: Fri Dec 07, 2007 6:08 pm
NEED an expert on cadapults, iam testing the angles and objects launched NEEDS SOMEBODY

### catapult, looking for experts?

Posted: Sat Dec 08, 2007 9:19 am
I suggest you do some background research on the web, using
"trebuchet" as the keyword. There are serious hobbyists who
do catapult launches for sport, but I doubt they'd be likely to
be patched into the Science Buddies network.

I don't know what size catapult you are contemplating but be
forewarned: these can contain a lot of pent-up power and
having a well-built and safely designed catapult is extremely
important. If you get to the test phase, this should be done
in a location where property damage or injury to bystanders
(or to yourself) cannot be allowed to happen.

If there's not enough time to build and test a catapult (Dec 20
is listed as the project due date), perhaps you can produce
desired results by doing computer simulations - varying mass,
launch angle, and launch speeds in methodical manner.

Peter Young

Posted: Sat Dec 08, 2007 2:19 pm
Hi! This sounds like an interesting topic, that has potential to go far. What grade are you in at school?

What type of catapult are you planning on using? For example, if you use a slingshot catapult, it may be more difficult to control the constant variables, but it will be easier to construct.

Don't forget to take into consideration that the shape and density may affect results.

Posted: Sun Dec 09, 2007 2:50 am
Hi MCC,

I have had the experience of building a trebuchet, slingshot, and crossbow ballista before and let me tell you they are a lot of fun. From your post it is hard to tell what level you are doing this project on, however a good understanding of newton's first 2 laws and more specifically gravity will be key to comprehending the mathematical side of the project. (Perhaps a short introduction on air resistance to explain possible discrepancies wouldn't hurt as well) As for the "fun" side, building a model out of wood would (pardon the pun) probably make the most sense for its easy connections and general cheapness, abundance and versatility.

If you are advanced enough to be trying to calculate the energy you initially impart on the object, then I would suggest a trebuchet as there is no need to worry about elasticity. Otherwise you are just trying to make the projectile launch consistently in which case I would suggest a slingshot design which should have a nice consistent release.

Good luck on your project and keep on updating.

### catapults

Posted: Tue Dec 11, 2007 9:15 pm
Iam an eight grader. Iam looking to build a wooden catapult. If you guys have any "blue prints" of a catapults please let me know. So far I have done background research on catapults. Iam now in the stage of building it, but I need some help. Thanks So Much for Responding! you left me with hope!

Posted: Mon Dec 17, 2007 9:34 pm
elin105 wrote:Hi! This sounds like an interesting topic, that has potential to go far. What grade are you in at school?

What type of catapult are you planning on using? For example, if you use a slingshot catapult, it may be more difficult to control the constant variables, but it will be easier to construct.

Don't forget to take into consideration that the shape and density may affect results.

Hi, I have to interview a person for my science project, is it possiable to interview you? I would really apprciate it. I built my catapult already and i just need some expert advice. It would be great if we could schedule it tommarrow around 6p.m Dec, 19 Iam pretty flexiable soo... lets cordinate.
THanks

### Re: catapult, looking for experts?

Posted: Mon Dec 17, 2007 9:35 pm
peteryoung wrote:I suggest you do some background research on the web, using
"trebuchet" as the keyword. There are serious hobbyists who
do catapult launches for sport, but I doubt they'd be likely to
be patched into the Science Buddies network.

I don't know what size catapult you are contemplating but be
forewarned: these can contain a lot of pent-up power and
having a well-built and safely designed catapult is extremely
important. If you get to the test phase, this should be done
in a location where property damage or injury to bystanders
(or to yourself) cannot be allowed to happen.

If there's not enough time to build and test a catapult (Dec 20

Hi, I have to interview a person for my science project, is it possiable to interview you? I would really apprciate it. I built my catapult already and i just need some expert advice. It would be great if we could schedule it tommarrow around 6p.m Dec, 19 Iam pretty flexiable soo... lets cordinate.
THanks

Peter Young

Posted: Mon Dec 17, 2007 9:35 pm
induced_discharge wrote:Hi MCC,

I have had the experience of building a trebuchet, slingshot, and crossbow ballista before and let me tell you they are a lot of fun. From your post it is hard to tell what level you are doing this project on, however a good understanding of newton's first 2 laws and more specifically gravity will be key to comprehending the mathematical side of the project. (Perhaps a short introduction on air resistance to explain possible discrepancies wouldn't hurt as well) As for the "fun" side, building a model out of wood would (pardon the pun) probably make the most sense for its easy connections and general cheapness, abundance and versatility.

If you are advanced enough to be trying to calculate the energy you initially impart on the object, then I would suggest a trebuchet as there is no need to worry about elasticity. Otherwise you are just trying to make the projectile launch consistently in which case I would suggest a slingshot design which should have a nice consistent release.

Good luck on your project and keep on updating.

Hi, I have to interview a person for my science project, is it possiable to interview you? I would really apprciate it. I built my catapult already and i just need some expert advice. It would be great if we could schedule it tommarrow around 6p.m Dec, 19 Iam pretty flexiable soo... lets cordinate.
THanks