NASA’s Glenn Research Center is experimenting with nickel-titanium memory alloy tires that resemble chain mail. It’s an intriguing angle — the tires can withstand heavier loads and at higher speeds. They’re airless and immune to puncture. Presumably they’re not literally chainmail but closer to a sweater in construction.
This tire is a culmination of a number of fascinating research drives. NASA has been experimenting with tensegrity structures as a means of building in space without spending a ton of rocket fuel on heavy hardware. These structures use tensioned cables to maintain a three-dimensional structure. The tires use the stiffness of the wire as well as internal stiffeners to maintain shape, without the need for a whole rim.
In addition to structural tensegrity, the memory alloy also helps keep its original shape by resisting deformation — it springs back into its original shape. When ordinary materials are stretched, you’re stretching the bonds between the atomic structures. NASA’s NiTi alloy goes through an “atomic rearrangement” when stressed, easing the forces put on those structures. As a result, the alloy can withstand 10% deformation versus 0.3% for spring steels, or about 30 times the deformation that a normal alloy could withstand without having permanent deformation occur — dents, basically. NASA’s tires can actually compress down to the axle and then pop back.
Continue reading “Will Your Next Whip Pack Memory Chainmail Tires?”
[masterfoo]’s mother-in-law suffers from a bad hip which would have sidelined her participation in the Fourth of July festivities. As a testament to the power of family and ingenuity, [masterfoo] built her a beach-capable wheel chair to give her some off-roading capability.
The frame is built out of 1.5″ PVC piping and the tires are 20×8-8″ inner tubes for ride-on lawnmowers. The lawnmower wheel inner tubes were cost-effective and fit the purpose, saving the need for the more expensive purpose-built-for-the-beach Wheeleez tires. They also have a fluid inside that plugs small punctures which will come in handy against he beach’s small cacti and other flora. This video was their guide for the foam insulation and plywood wheel assembly, also employing the handy man’s secret weapon to protect the tube from the rim’s plywood edge. Check it out in action!
Continue reading “Cheap and Effective Dune Buggy Wheel Chair”
Somewhere between the early tires forged by wheelwrights and the modern steel-belted radial, everyone’s horseless carriage rode atop bias-ply tires. This week’s film is a dizzying tour of the Brunswick Tire Company’s factory circa 1934, where tires were built and tested by hand under what appear to be fairly dangerous conditions.
It opens on a scene that looks like something out of Brazil: the cords that form the ply stock are drawn from thousands of individual spools poking out from poles at jaunty angles. Some 1800 of these cords will converge and be coated with a rubber compound with high anti-friction properties. The resulting sheet is bias-cut into plies, each of which is placed on a drum to be whisked away to the tire room.
Continue reading “Retrotechtacular: Brunswick Shows A Bias for Tires”
[Nicolás] often rides his bike in the city, and on more than one occasion has ended up with a flat tire. A flat tire might not sound like a big deal, but imagine if you are a few miles from your destination and running late – now your day has gone from bad to worse.
He was contemplating how he might protect his bike’s tires from being punctured by glass and other debris, when he came across some old car seat belts that used to serve as straps for various messenger bags. He pulled the tires off his bike and after removing the inner tubes, he unrolled the seat belts inside the wheels. The belts were cut to size, then the tubes were reinserted into the wheels and inflated as normal.
He hasn’t run into any glass shards just yet, but [Nicolás] is betting that the reinforced nylon mesh of the seat belts will keep his tubes safe whenever he does.