if this actually works, some poor kid is going to cut him or herself…
Wes, that isn’t a bad idea to try. Oil will cool the lids a lot less quickly, preventing embrittlement of the material.
Texases, once you factor out the fluids, passenger, and error budget, that puts it right in the range of an ultralight as defined by the FAA.
the oil will add carbon, making it harder and more brittle, a bit of heat tempering after may help reduce the brittleness
but yes, plunging it into cold water will make it brittle also. it s all about the alignment of the molecules in that case
also, heating steel too much will take the temper out, when using heat to shape steel you have to be careful not to overheat the steel or it will crystallize, and the shaping won t take and the structural integrity of the steel will be compromised. you also should not cool it too quickly, as with water if it is anything other than decorative metal
the same is true for welding. you often have to allow time for cooling when applying multipass welds to prevent the base metal, and the weld material, from overheating and crystallizing
2000 pounds = 255 pounds plus gas and passenger??
I’m a bit baffled here: they make landing gear for these airplanes. These aren’t ultralights:
I should add that it would be dishonest of me not to admit that I’ve realized during the discussion that the OP wants to use the metal for a toy, and while mild steel, PVC, wood and other materials aren’t considered spring material, the can tops just might work for the toy if the proper springiness can be process into them. Many materials not considered spring materials have the ability to store some energy and return it. Except lead and gold. And marble. And marble flexes some extremely tiny amount before being overcome by tensile force failures.
Perhaps considering the application I’m being too strict with the term “spring material”.
Which would return me to one of my original posts; try it (the original idea of heating and chilling the can tops) and let us know how you made out. Try it with oil, as wes suggested. Motor oil might even work well. It isn’t aeromatic, meaning it wont vaporize and combust readily, so it’ll be safe, and it doesn’t transfer heat anywhere close to as fast as water, so it’ll be more of a controlled process.
when we ve needed a center punch in a pinch, motor oil has worked just fine
Texases, you forgot to include the “error budget”. That’s standard design practice for structural members.
Is it your belief that the struts in your photos are springs?
Yes, as they show on their web site, click through (blue button) to the video there.
As I said, I can’t open the video. Sorry.
fender washers!!! large fender washers!!!
eureka! I knew there was something lurking in the blackhole that is my memory banks that would make good wheels with little effort…
^If they deflect under landing, they’re springs. You really couldn’t fly a plane with 100% rigid landing gear, unless you had some really big tires. The stresses on the mounting points would be astronomical!
Even a “rigid” fork bicycle has a spring function in the rake-forward of the fork–under load, it will flex by bending further. Some rigid forks on road bikes are Al. (Plenty are Cr-mo Fe, for those who are willing to accept a slight weight penalty for a smoother ride.)
TSMB - Here’s some more info from their web site:
"Material Width and Thickness: We use aircraft grade 7075 aluminum heat treated to T6 specifications for most light aircraft applications. The width and thickness of the material determines the spring rate and ultimate strength. It is important that these values be properly chosen. If you are retro-fitting or replacing gear to fit an existing dimension, please give us that information. Otherwise we will recommend material width and thickness appropriate to your aircraft based on its gross weight, wing loading, and gear geometry. "
And here’s how you can order your aluminum landing gear, custom made to your plane:
http://www.groveaircraft.com/layout.html
Texases, you forgot to include the "error budget". That's standard design practice for structural members.No, those are the max rated landing weights of the respective aircraft. A Glasair is right around 2200#, for instance, and usually less. It's like my 8.8 Ford axle is rated for 3,900#: they know the axle will have to withstand some level of G-amplification; they figure that into the design, but don't necessarily bother telling the end user about it. It's not like they toss 10-lb weights in the bed of a parked truck and note the point at which the axle snaps!
Here’s another video of the Grove aluminum landing gear in action:
“I’m not using the lids as wheels. It’s for the steering wheel. I want to have two lids, slightly bowl shaped, opposed to each other, then when you press on the center it makes a clicking sound but returns to its original shape. Like those clickers used in kids games. For the horn effect.” - OP
LOL, I suspect we’re getting so sidetracked by the debate about the use of aluminum for springs that we’re losing sight of the original purpose!! 
In the final conclusion, I admit to having been too strict with the definition of “spring material”.
But while I concede that aluminum of the proper alloy properly heat treated does have some springiness, and I acknowledge that aluminum alloys do have “spring rate”, I also maintain that aluminum is not a spring material. Aluminum is used in this application not to absorb energy and return it, but for its light weight, using the spring rate of the aluminum as best possible for the application while avoiding the weight that actual springs would add to the aircraft.
By the way, I did get to see the video and the amount of flex allowed is actually more than I would have expected… but not enough that I’d categorize them as springs. But I admit that this is quibbling on a technical definition.
I also noticed that the application didn’t appear to be an ultralight. I can only assume that the error budget has already been factored out of the “max weight” rating. And that would be the normal way to do it. I’ll acquiesce to this point outright.
oops…
Oh, I can live with it. I think we simply have different perceptions of what constitutes spring material. I was using a much stricter definition. Not a problem.
no, I meant “oops” about my missing the bit about it not being for wheels…
Oh. Okay. Mea Culpa. 