UpForce

[Frank(Aflak)]

Originally Posted by Brant Bowen

I'm not very good at physics, but the force would have to be greater than 130 lbs. i think, maybe something like 130 times 9.8 to counteract gravity???

Anyways I still don't think you can get a prop spinning fast enough to take off. Also take into consideration how much it would take to control where that thing goes.

Sound like a safety hazard to me.

no, a 130 pound force acting directly up on your robot will cancel gravity completely. to actually go up instead of hovering, you need more.

But you aren't going to get 130lbs of force out of a propellor powered by the kit motors.


HEY!! What if you used a wind up propellor using all that elastic tubing . . . .

hmmmmmmmm.

Ach, I will never be able to sell that to my team, but hey, its an idea.

The bad part is this: if you miss the bar and your prop winds down 15 feet in the air, you no longer have a robot!

Heh, imagine it flying out of control into the crowd, with rapidly spinning blades of DEATH!!

[Mercutio]

D'oh! Frank(Aflak) posted what i was going to say as i was typing! That happens to me WAY too much...

Actually, if your prop wound down in midair the bot might not crash. You'll start sinking slowly at first as the force from the prop got below 130 lbf, and then you'd accelerate faster and faster. It all depends on how fast the prop winds down.

Now if your prop got jammed and stopped in midair...

[DaBruteForceGuy]

Who said the robot needed to be 130lbs??

[Frank(Aflak)]

Originally Posted by Mercutio

D'oh! Frank(Aflak) posted what i was going to say as i was typing! That happens to me WAY too much...

Actually, if your prop wound down in midair the bot might not crash. You'll start sinking slowly at first as the force from the prop got below 130 lbf, and then you'd accelerate faster and faster. It all depends on how fast the prop winds down.

Now if your prop got jammed and stopped in midair...

No, it would still lead to a vicious crash . . . you see, when the prop winds down from giving more than you weight to giving a force equal to your weight . . . your robot is still going upwards, so that yes, your prop will slow your descent . . . but you will still hit pretty hard. Hard enough to bend thin driveshafts, break bearing blocks, tweak frames, etc.

It would be cool to see.

and the robot doesn't need ot be 130 lbs, but when he says 'how to get an upforce of 130lbs" we are assuming he is talking about moving a 130lbs platform.

Everything we said still applies, just change the numbers.

[mtrawls]

In the classical system, as I understand it, a pound of force is the force gravity makes on an object whose mass is one pound of mass.

If you have to talk about force in the classical system, I suggest you use the unit of force called the slug.

Whoa! Physics is confusing enough without confusing the terms "mass" and "weight." Let's get things straight. The POUND is the unit of FORCE in the Imperial (British) system. Weight is defined to be W = mg, which is a force vector. Weight is then a force, and the POUND is also a unit of WEIGHT. The SLUG is the unit of MASS in the Imperial system. Here on Earth, where g=32ft/s/s, assuming that the robot is short enough that g does not change drastically (probably a safe assumption assuming the height limit!), then we can convert between weight and mass relatively easy (W=mg) -- but beware not to confuse the two in a physics equation, or in your understanding. If all that sounded a bit confusing (too many wierd names ... afterall, who's heard of a slug?) ... that's why we use the metric system (well, I guess not many more have heard of a Newton, but that's inconsequential).

[IronSlayTallica]

maybe if you use 26000 muffin fans.

Do you know the muffin fan...

[Frank(Aflak)]

Originally Posted by IronSlayTallica

maybe if you use 26000 muffin fans.

Do you know the muffin fan...

that would be less airworthy than our robot last year (which is saying lots).

Because a muffin fan cannot lifta a muffin fan. 26000 muffin fans cannot lift 26000 muffin fans.

[Guyute]

most engines out there aren't capable of lifting even themselves straight up. in order to build a flying robot, you would have to use ever shred of power to lift it, leaving none availble for things like, oh, drivetrains, ball grabbers, etc.

- Frank(Aflak)



who said that we were going to have a drive train or ball grabbers...our pure intention to this would be to control the bar 100% i'm not going to go into depth on how we will do that specifically, but its going to be done.