A little remote control motorized car you insert into a balloon before you blow it up which has a rotating magnet on the bottom. In a second balloon, you put a round magnet to which the magnet on the little car in the first balloon attaches itself, so the two balloons are held together but may rotate freely as the little car runs.
When you turn the little car on, it starts the balloon it's in turning and since the other balloon is attached via the rolling magnet the two balloons counter- rotate respective to each other and should fly through the air due to the friction on the backward rotating portion of the balloons.-- doctorremulac3, Mar 23 2014 Magnus effect http://en.m.wikiped.../wiki/Magnus_effectOdd, yet real. [8th of 7, Mar 23 2014] Balloon-o-stat schematic https://www.dropbox.../BALLOON-O-STAT.jpgLittle remote control car makes it go forward or backwards. Wonder if you could make it turn as well? [doctorremulac3, Mar 24 2014] [wbeaty] explores a similar concept http://amasci.com/a.../vortgen.html#blimpBut much more complicated to implement than yours. [scad mientist, Mar 24 2014] I sort of get this, but I don't see how the counterrotating balloons generate lift.-- MaxwellBuchanan, Mar 23 2014 It's called the Magnus effect.
<link>-- 8th of 7, Mar 23 2014 The magnus effect, per se, generates a force at right angles to the principal direction of motion (as in a curve-ball).
Spinning a balloon, or a pair of balloons, will not necessarily achieve much.-- MaxwellBuchanan, Mar 23 2014 Where the balloons make contact, the effect is negated. Opposite the contact point, the moving balloon surfaces push the two balloons along. Not very fast or very efficiently, but they would move.-- doctorremulac3, Mar 23 2014 Yep. Like a cross section of a vortex ring with a teeny center. If these balloons had little hairs on them they would truck right along, but then that would be cilia.-- 2 fries shy of a happy meal, Mar 23 2014 [2fries], your suggestion bristles with impracticalities … it might just work, but it would probably be a close shave.-- 8th of 7, Mar 23 2014 If the pair of rotating balloons is symmetrical about a horizontal plane which passes through the interface how can it produce a net vertical force?-- EnochLives, Mar 23 2014 See above.
It would move horizontally, not vertically, with the car holding balloon being at the top and the round magnet balloon being on the bottom.-- doctorremulac3, Mar 23 2014 I don't get that at all then.The way you just described it, both car and magnet end up sandwiched between doughnuts and your center of mass makes the whole thing tip on its side.
It must be a semantics thing,by //rotating magnet on the bottom// do you mean in-line with the little cars' motion, or perpendicular to it, or horizontal to the little car?
By //round magnet// in the second balloon, do you mean like a cylinder or like a sphere?How does this fly if its travel is horizontal?
It worked in my head only a minute ago and now it's just gone. Any chance of a sketch?...-- 2 fries shy of a happy meal, Mar 24 2014 Hulla.-- normzone, Mar 24 2014 //Any chance of a sketch?...//
Yea, ok. See link.-- doctorremulac3, Mar 24 2014 Ah. It will work but your car won't remain upright.-- 2 fries shy of a happy meal, Mar 24 2014 Sure it will. Is the heaviest part of the assembly so it hangs down at the bottom of the top balloon. It's too heavy to climb up the side of the balloon so the balloon just rolls under it.
The bottom ballon is just hanging from the underside of the heaviest element which is the car and it's rolling magnet.
To visualize it, just ignore the bottom balloon for a second. The car just rolls around the trying to climb up the balloon walls but can't because the balloon is rolling under it treadmill style. Then you add the bottom element that rolls in mirror image to the top.-- doctorremulac3, Mar 24 2014 If the car is the heaviest element then it will want to hang upside down unless only the upper balloon is helium filled or the magnet roller outweighs the car.
If both weigh the same and the balloons are air filled then it will tip and travel horizontally.-- 2 fries shy of a happy meal, Mar 24 2014 Ohh, I get what you're saying. I forgot about the lift from the lower balloon. Yes, you're absolutely right. Duh.
Consider the drawing an overhead view.
Or, as you've pointed out, just put air in the bottom balloon.
Thanks 2fries.-- doctorremulac3, Mar 24 2014 Yes, that should work. I hadn't realised that the whole assembly was neutrally buoyant.-- EnochLives, Mar 24 2014 //neutrally buoyant// [marked-for-tagline]-- MaxwellBuchanan, Mar 24 2014 I went back to the original notation and re-wrote it in English since the original post was written in sort of a coffee break rushed Englishesque fashion.
Should make a little more sense now.-- doctorremulac3, Mar 24 2014 A very similar concept was documented by [wbeaty] on his own site <link>. It's similar in the way that it would fly but would be complicated to implement. [doctorremulac3]'s version should be pretty simple to implement, but probably won't have quite the performance that [wbeaty] was hoping for. Acceleration would be limited by the magnetic force holding the balloons together.
It seems like you might be able to have some vertical control if you designed the car to shift its weight forward of back relative to the position of the magnet. That would allow it to point up or down slightly.-- scad mientist, Mar 24 2014 [+] flying boobies.-- FlyingToaster, Mar 25 2014 Absolutely.
Although ladies might visualize something more, ahem... masculine, depending on their mindset.-- doctorremulac3, Mar 25 2014 Oh. I thought you said "flying bobbles", re Vernor Vinge.-- normzone, Mar 25 2014 This should work very well but... post- acceleration, the speed of the outer balloon walls is zero wrt the outside air, and the speed of the cars along the balloon wall is 2x the speed of the entire craft. The cars would have to race pretty fast.
How long would batteries last, i.e. how efficient is this compared to using tiny propellors? Tiny propellors are *very* inefficient. But tiny cars racing through a helium atmosphere would need good aerodynamic design, like say those yearly entries in the solar-powered race across Australia.
Also, this toy might have very good brakes: if the cars suddenly stop, the balloons probably halt instantly in midair. Don't forget that air density is about 2lbs per cubic yard, so the toy is connected by viscosity with many many pounds of room air.
Build an underwater version! How fast could it go before turbulence would screw up the propulsion effect?-- wbeaty, Apr 26 2014 > the ladies might visualize
Your invention could become the propulsion for a huge blimp! Place a pair of giant helium-filled spheres near the rear, so any trailing turbulence isn't dragging across the blimp surface. Then turn on the magnet wheels, and the blimp thrusts itself rapidly across the Empyrian, like some enormous
Colonel: What is it, son?
Johnson: I don't know, sir, but it looks like a giant
Jet Pilot: Dick!
Dick: Yeah?
Pilot: Take a look outta starboard.
Dick: Oh, my God! It looks like a huge--
Bird-Watcher 1: Pecker!
Bird-Watcher 2: Oh, where?
Bird-Watcher 1 : Wait! that's not a woodpecker. It looks like someone's--
Army Sergeant: PRIVATES! We have reports of an unidentified flying object! It is a long, smooth shaft, complete with--
Umpire: 2 balls!-- wbeaty, Apr 26 2014 random, halfbakery