# MythBusters experiment proposal - (hopefully a joint effort for forum members)

Discussion in 'Aircraft & Aviation' started by Hans Christian, Apr 23, 2007.

1. ### Hans ChristianActive Member

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I mentioned there that I conducted some measurements during my catapult launches and recorded some rediculous speeds (ave. 100 kph) and accelerations (about 254 m/s(sq) )

well, I punched these numebrs again in my calculator, and I found out that (if my readings are correct), if that acceleration rating is sustained for just a second, the glider(s) would have reached speeds in excess of 500 mph, and if the acceleration extends another 1 second (that makes 2), it would have reached well over 1,000 mph, well over Mach 1...

I am skeptical about my calculations (and the data I recorded), but if there is a sense of realism in this scenario, then I'm proposing a (lets say) "myth"

- Can a cat-launched cardboard glider go supersonic?

well, the biggest hurdle here is where the hell someone can find a pretty powerful catapult to pull this one off, or how to sustain 254 m/s(sq) acceleration for at least 1.5 seconds...

and if the launcher can indeed fling these things to Mach speeds, would they survive?

I need help with this one guys, I am interested to pass this to the guys at MythBusters for them to have a look, of course, they are free to explore other methods and/or equippment to use (i.e., they may use steam instead of rubber bands etc.)

well, I'm planning to improve my "usual" catapult (a long, strong slab of wood with legs attached and anchored to the ground, and using a long chain of rubber bands, with 3-4 strands per ring) that I used to record the numbers I've mentioned, by using leverage (pulley assisted) to multiply the force generated by the rubber bands to fling the plane to flight...

Hopefully someone here could look at this topic and chew on this scientifically to see if it can be done...

Thanks everyone! :-D
2. ### Hans ChristianActive Member

Joined:
Dec 14, 2004
Messages:
991
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I mentioned there that I conducted some measurements during my catapult launches and recorded some rediculous speeds (ave. 100 kph) and accelerations (about 254 m/s(sq) )

well, I punched these numebrs again in my calculator, and I found out that (if my readings are correct), if that acceleration rating is sustained for just a second, the glider(s) would have reached speeds in excess of 500 mph, and if the acceleration extends another 1 second (that makes 2), it would have reached well over 1,000 mph, well over Mach 1...

I am skeptical about my calculations (and the data I recorded), but if there is a sense of realism in this scenario, then I'm proposing a (lets say) "myth"

- Can a cat-launched cardboard glider go supersonic?

well, the biggest hurdle here is where the hell someone can find a pretty powerful catapult to pull this one off, or how to sustain 254 m/s(sq) acceleration for at least 1.5 seconds...

and if the launcher can indeed fling these things to Mach speeds, would they survive?

I need help with this one guys, I am interested to pass this to the guys at MythBusters for them to have a look, of course, they are free to explore other methods and/or equippment to use (i.e., they may use steam instead of rubber bands etc.)

well, I'm planning to improve my "usual" catapult (a long, strong slab of wood with legs attached and anchored to the ground, and using a long chain of rubber bands, with 3-4 strands per ring) that I used to record the numbers I've mentioned, by using leverage (pulley assisted) to multiply the force generated by the rubber bands to fling the plane to flight...

Hopefully someone here could look at this topic and chew on this scientifically to see if it can be done...

Thanks everyone! :-D
3. ### SteveMMember

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Your calculations are assuming a vacuum. Include some atmospheric drag calculations and you'll get VERY different numbers. I think that trying to push a paper model supersonic will shred it into confetti.
4. ### SteveMMember

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Your calculations are assuming a vacuum. Include some atmospheric drag calculations and you'll get VERY different numbers. I think that trying to push a paper model supersonic will shred it into confetti.
5. ### goney3Member

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MmmMmmm!... scientific confetti Sounds like something fun!
6. ### goney3Member

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MmmMmmm!... scientific confetti Sounds like something fun!
7. ### wunwinglowActive Member

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I wish my arrows would go supersonic; I might hit a few more golds then...

Tim
8. ### wunwinglowActive Member

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I wish my arrows would go supersonic; I might hit a few more golds then...

Tim
9. ### Stev0Active Member

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DAMN YOU PHYSICS!!!

Yes I think we have forgotten drag and perhaps environmental conditions.
10. ### Stev0Active Member

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DAMN YOU PHYSICS!!!

Yes I think we have forgotten drag and perhaps environmental conditions.
11. ### KazMember

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With no thrust, and dropping it straght down, won't it reach (a paper 'planes) terminal velocity?
Peregrine Falcons hit about 200 mph.

In our local book store we have a paper plane launcher, it comprises of a set of rubber wheels set horizontally on a launch pad, these are powered by a motor and the fuselage is coaxed in between them and its then shot out

like this one
http://www.amazon.co.uk/Great-Gizmos-Paper-Plane-Launcher/dp/B000EOQXBM
12. ### KazMember

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With no thrust, and dropping it straght down, won't it reach (a paper 'planes) terminal velocity?
Peregrine Falcons hit about 200 mph.

In our local book store we have a paper plane launcher, it comprises of a set of rubber wheels set horizontally on a launch pad, these are powered by a motor and the fuselage is coaxed in between them and its then shot out

like this one
http://www.amazon.co.uk/Great-Gizmos-Paper-Plane-Launcher/dp/B000EOQXBM
13. ### paper warriorMember

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What if you strap a rocket to it? I have a paper airplane that could achive this, with a few mods. (re-inforcing the wings)
14. ### paper warriorMember

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What if you strap a rocket to it? I have a paper airplane that could achive this, with a few mods. (re-inforcing the wings)
15. ### TexmanGuest

Yes indeed. You have four forces acting on the airframe. Lift, thrust, drag, and weight. Each must be considered on its own, and in conjunction
with each other and the density of the air at various altitudes, which changes with temperature and humidity, etc. It is by no means and exact science.
16. ### TexmanGuest

Yes indeed. You have four forces acting on the airframe. Lift, thrust, drag, and weight. Each must be considered on its own, and in conjunction
with each other and the density of the air at various altitudes, which changes with temperature and humidity, etc. It is by no means and exact science.
17. ### Rick ThomsonMember

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Of course if you have enough thrust the other three don't count, as the Phantom and 104 proved...
18. ### Rick ThomsonMember

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Of course if you have enough thrust the other three don't count, as the Phantom and 104 proved...

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