Circa Jan 2000.
When we moved into The Money Pit here in Black Forest, I discovered an old C-Band satellite dish in the back yard. These lovely things (often called Big Ugly Dishes) can receive all of about 2 unencrypted TV channels these days but one of the channels that comes in strong is the NASA TV feed. For a long time my kids only choice of TV was to watch the NASA channel or not to watch TV.
I have been a fan of the Space Program since I was a kid. I even applied to work at the Kennedy Space Center when I left Microsoft. At the time I only had a green card and KSC is a bit funny about putting Aliens in space. Mostly they only want aliens on the outside of their spacecraft.
One of the things you see astronauts doing a lot is practicing throwing up in the "Vomit Comet" or swimming around in a giant pool dropping little tiny screws down the drain as they prepare to repair the Hubble Space Paperweight (as Dave Barry nick-named it). I thought my kids would enjoy some of this stuff and set about welding up a 3D gyro for them during the 1999 Christmas break.
The machine before the kids painted it
I think this is probably in the "Don't try this at home" category unless you are a pretty good welder and have very willing kids.
I made my machine from 14 gauge square steel tube. this was because I had no way to bend the 3" dia round tube I would have liked to use. The steel cost me about $300 and the bearings about another $300. I used spherical self-centering ball bearings for the outer set and taper-roller pairs for the inner sets. I put it all together with a small MIG welder (ESAB Migmaster 150). After initial trials I added a few more supporting struts - evidently my 7 year old is a bit heavier than I thought.
The way the kids are tied (yes that's right) into the machine is a bit barbaric but keeps them from slicing off a finger or foot. I put them in a full-body rock climbing harness which is clipped at waist level to the center of the inner-most frame. The hands and feet are held in place by rock-climbing style runners (nylon-like webbing) clipped to the upper and lower tubes of the inner frame. the frame tubes at the top and bottom can be moved to accommodate different height kids.
My son Mark tied into the machine.
I have not yet got into the machine myself. I do want to but never seem to be able to find willing helpers on the days my bravery gets above 7.
I really want to put a chair in the middle so you can sit and be held in place by an aircraft-style 5-point harness. Then I want to add a 3-axis motion controller and some jets so you can fly it like a space capsule. the jets are a bit tricky. Hypergolic fluids would work well but they are a bit difficult to get off the kids clothes in the family washing machine (wife deterrent factor). I also thought I could use a tank of water pressurized by one of my scuba tanks. The hand controller would use the gas pressure to force water out the jets. This is the one scheme I think might work well. I did consider electric motors but you need a lot of slip rings for the power and controls and it just sounds too expensive.
If anyone at NASA is throwing out the result of spending my tax dollars on a similar device, please let me know - I'll come and get it.