I can't believe the sled out jumped the bike. 220lb jgr built 450 goes 378ft and the 440lb 800cc sled (2 refridgerators) with a lot more wind drag goes 412..those numbers don't add up? Even all the people involved were thinking the bike go farther..history prooves it over an over. The speed run said 97mph target was 98 prettty close..

I might be the last post of 2011 and the first post 2012 so happy new year!!!

Actually the weight helps the sled. It isn't affected as much by the wind drag once it's up to speed. It looked like the bike had too high of a trajectory.

quote:

Originally posted by Paul 061:
Actually the weight helps the sled. It isn't affected as much by the wind drag once it's up to speed. It looked like the bike had too high of a trajectory.

Wrong..weight has huge effect and wind does have some effect as well..bikes always go farther than sleds period, correct math.
Even the redbull crew forseen it that way and the riders..Paul do you really think the weight helps the sled go farther?

When they are up to speed, the weight of the sled provides more inertia and thus decreases the effect of the wind. Imagine a cannon ball going through the air versus a softball which one will be effected by the air drag most? Remember all things are effected by gravity the same( they fall to the ground at the same velocity regardless of their weight) so the weight has no effect there. When you look at trajectory calculations, it is all velocity and angle. What do you think the weight does? Do a google search for projectile motion formuli and you too can be a long distance jumper regardless of weight.

This message has been edited. Last edited by: Paul 061,

Okay Mr Engineer your probaly right but I still think weight has effect from when you leave the jump going up to the top of the arch..effects the overall distance.
It's amazing the riders and engineers planned differently and were wrong..that's sketchy!

I think what happened was his trajectory. If you watch the video, he is much higher than the snowmobile even though the ramps appear to be the same angle and their speed is about the same.. I'm not a snowmobile guy so I don't know about their suspension but I think madison kinda seatbounced with the way he was back on the bike tucked. When he left the ramp his angle of attack was steeper casuing more height and less distance. Madison stood up during the flight causing alot of drag and slowing him down. The bikes are at a point where they don't have enough HP to go fast enough. Maybe a punched out CR500 would do better or a big bore flat track motor in an MX frame.

quote:

Originally posted by TRA-742:
but I still think weight has effect from when you leave the jump going up to the top of the arch..effects the overall distance.

Nope no effect. The only effect would be HP going up the ramp. If there wasn't enough HP to hold the speed going up the incline.

Arch of the jump I mean when your flying in the air going up to the highest point of the jump before you start coming down..
Is it easier to through a 5lb weight up in the air than a 10lb weight?

I have to agree with Paul in all aspects up to and including aerodynamic drag (ref: http://en.wikipedia.org/wiki/Drag_(physics)). Anyone ever see a kid on a 65cc huck a 60' tripple, they do it just like the big boys. Just gotta have enough speed. As for 5lbs vs 10lbs that makes no difference to me so long as forward speed is maintained, my only concern at that point is in ramp build materials - will it collapse under the vertical load of the vehicle impact thus altering trajectory. My calcs had Robbie and Levi going vertical at just over 2Gs max. By looks of it Robbie had a greater Reynolds (aero-drag) number. Sled goes further.

ref: ESPN Sports Science (http://search.espn.go.com/sports-science/videos/6)

quote:

Originally posted by TRA-742:
Arch of the jump I mean when your flying in the air going up to the highest point of the jump before you start coming down..
Is it easier to through a 5lb weight up in the air than a 10lb weight?

That's where HP comes into play, it takes more strength to accelarate the 10lb weight than the 5 lb weight for sure but if they have the same final velocity they will go the same height.

If they left the ramp at the same speed, they will attain the same altitude. The only thing bringing them back down is gravity and all things fall at the same speed regardless of weight. Thats how we predict the motion of the planets, the orbit of satelites, the range of a Howitzer AND the length of a long distance bike jumper. You wanna clear any Supercross triple? Take the angle of the jump and the distance, do the math and hit it at that speed. Who needs balls, you just need a calculator :-)

I still think the angle of launch was greater on the bike due to the suspension.

A actual horse makes HP just like engine in dirtbike or the human body. If I threw up in the air 10lb weight and then next threw up 5lb weight I'm pretty sure the 5lb would go higher..so weight had effect

The weight had an effect in the sense that it was more difficult to get it up to speed. If you launch each weight with a rocket launcher (or some other thing than had more than enough power to launch) and they left the launching device at the same speed they would go the same height. Again, go back to the math, there is no weight variable in the equations.

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So if you dropped a 15lb bowling ball and a tennis ball off the top of the space needle simultaneously, gravity would pull them to earth with the same velocity and they would hit the ground at the same time?

In theory yes, there is some wind resistance and it doesn't work so well with real light things. If you dropped a 15 pound bowling ball and a 2 lb lead ball they would hit at the same time. Go up on your roof and drop a golf ball and a bowling ball, they will hit at the same time. And you could calculate how long it wold take to hit. Ain't physics cool!

Don't know what all the talk is about, all that was proved back in 1971 with Apollo 15 and Moon mission. Pretty cool then, even now.

Aero-drag and Reynolds numbers...Apollo 15, July 26, 1971, Lunar surface...During EVA 3, the third and final moonwalk of the mission...Scott performed an experiment with a feather and hammer to test Galileo's theory of objects in gravity fields in vacuums.

ref: http://en.wikipedia.org/wiki/Apollo_15

Another Galileo tid bit. Go to a park with swings. Have two people sit in two swings, have two other people pull them back. Start one swing at head height, the other at waist height. It will take the same time for them to make a complete swing regardless of the weight of the person or the height they are lifted to.