There were some heavy trucks that had aluminum axles. I believe International made them. For whatever reason they went away. My guess is fatigue life and/or cost.
I used to work for Dana and we made the aluminum frames for the Z06. You could pick up one end easily by yourself. Very low production, about 50 per month. Rich
Aluminum also has about 1/3 the stiffness of steel. A frame of similar design in alum vs steel would be much more flexible in alum. As pointed out, alum can be used, but you just need to design around the specific properties. Shape and desiogn have a significant effect on stiffness, not just modulus of elasticity.
New Jaguars and some other high dollar European cars have frames made of Aluminum stampings that are put in a jig and robot welded, Very rigid and light weight.
[3: You don't see this kind of thing discussed here because, unless you want to discuss a particular pre-'65 example, it's way off topic here.[/QUOTE] Both the UNCERTAIN "T" AND CORTAPASI & BUTLER "GL*** SLIPPER" come to mind
Bruce has it right. It's unsprung weight loss you're after. Superbell makes an aluminum front axle. Anybody know of rear axles in aluminum suitable for a hot rod? Ralph
I seem to recall reading something about T-based board-track racers having their frame rails replaced with aluminium sections. If that's true it's amply traditional. Then, board-track racers weren't expected to last very long, so the fatigue thing is still an issue. I considered doing the '31's body framing in aluminium. The weight numbers looked OK until I started considering rigidity. Wood is more rigid for the weight! - and it'll take a nail for fixing.
I ran an all aluminium Acura NSX race car for a couple of years, although it saved weight it was a major pain in the ***. Everything has to be re thought as aluminium is totally different when it comes to load bearing structures. Any metal structures need to be attached mechanically, they can't can't be welded on. Not worth the h***le.
Traditional enough, Rootie, but aluminum?? What a boat anchor! I have one of those in magnesium...I keep it tied to an old cylinder head so it doesn't drift away.
On the unsprung weight...not only do we need lowered to improve traditional steel roadsters, which already are in bad territory for sprung/unsprung ratio, but making the car lighter (say your 2,000 pound steel Model A becomes a 1,400 pound aluminum Model A) while keeping the dropped axle and Ford 9" will produce a significantly worse car, overwhelmed by its unsprung weight. Handling and ride would likely suffer badly and might even become dangerous on rough roads. Ever see a flic of a Monster truck, one with tires taller than a man and gigantic axles from military heavy truck? They sometimes go into axle hop that flips them over after going over an obstacle too fast...NO amount of spring or shock action can control that stuff under a vehicle that does not greatly outweigh it. Going very light in vehicle construction could only be reasonably handled now by full independent suspension, preferably with brake weight moved inboard...I don't think there's anything out there in rear ends that would do. It would be cool to see the kind of work Halibrand put into race car axles (Mag everything, open axle shafts, etc.) but engineered for streetable use with diffential and full covers.
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