I’m aware that aluminum does not have a fatigue limit like steel or titanium, and so even for very small stresses there will inevitably be fatigue cracking after a sufficient number of cycles, but other than fatigue cracking- is there any other reason why springs are almost never made of aluminum? Is there a special application that I just don’t know about where aluminum springs are used?
A fatigue limit is defined as an amplitude of cyclic stress that allows infinite repetitions without fatigue. Aluminum does not have a distinct limit, and so it appears that there is no level of stress below which there can be infinite cycles without fatigue failure. I thought that the term “fatigue limit” was widely understood to have this meaning, consistent with this Wikipedia article: http://en.wikipedia.org/wiki/Fatigue_limit
You have the answer in your question and you are quite aware of the endurance limit of Aluminum.
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Why are springs so rarely made of aluminum?
I’m aware that aluminum does not have a fatigue limit like steel or titanium, and so even for very small stresses there will inevitably be fatigue cracking after a sufficient number of cycles, but other than fatigue cracking- is there any other reason why springs are almost never made of…
Any time a horse is “behind the bit” it means he’s avoiding contact. It’s just starting spring and with the time off, it might be a good time for a change. Every heard of a Donal? It’s like an aluminum bosal hackamore. I tried to find one for you on Ebay but most folk who have them, rarely sell them. What this will do is allow your horse some time off from using a bit and get him to “rethink” his carriage. Also, to get him to use his haunches more and round off, you can do a lot of work using the rail to help you. Try some pivots on the haunches, this will get him to use his back end more. Start off paralle to the rail and keeping his outside rear leg stationary, get him to pivot on it and reverse direction. Once he’s doing that, then try a sitting trot in SMALL circles, try a circle in corner of your arena. As he progresses, then you can move up in gaits.
cost. carbon steel is easy to create the desired characteristics. You have the wrong information about aluminum and fatigue. Maybe pure al doesn’t fatigue, but pure al is very soft and you can’t make a spring of it. Any alloy of al that would be suitable for a spring will work harden and fatigue quickly. That is why helicopter rotors and structural parts of airplanes have a limited life and have to be inspected often.
You have a nice looking pony, and obviously he has the potential to really jump well. You’ve obviously done a very good job all alone. I didn’t look at every photo since I have slow dial-up internet and it takes too long. I did notice that in some photos he was past the vertical, but in others he was the opposite. He was carrying his head quite high in many photos, in others lower. So obviously he is not really consistent in his headsetting. That may be because you aren’t certain what you’re after, and you possibly aren’t rewarding him when he’s exactly right and letting him know where to be. Is there any chance you can haul your horse and ride under a show trainer? If you could ride under an expert once a week for a month or two I think you would be amazed at the changes he makes. It is almost impossible to tell how your horse looks from the ground when you’re in the saddle. A trainer would be able to tell you how your horse looks, they would be able to tell you the ideal frame for the type and conformation of pony you own, and they would give you immediate feedback on when to increase the pressure and when to give a bit of release. Without help from the ground I think you will not achieve a consistent frame. I know I couldn’t do it. Once you have truly learned it on one horse you’ll find it easier with the next, but I can assure you, even the pros get people to help them. The place that I ride is a family operation with husband, wife and adult daughter, plus two hired trainers working there. They always ask each other “Is Tex reaching underneath himself with his back end?” and “Is his neck level enough?” etc. If the professionals, who have been in this for 20 plus yeras, still need eyes on the ground, then we amateur’s shouldn’t feel bad that we need a bit of help, too. Just make sure you find the right trainer. You are looking for a show rider, not just your average 4-H leader who doesn’t know the current look and style of show horses (Not knocking 4-H leaders, I’ve been one, too, but they can vary from person to person, which is my point) One thing I wondered is – how much leg are you using when headsetting? I was taught that you need equal leg to hand, and that you soften both when the horse gets into the correct position, and increase pressure to both when they aren’t. By the looks of your horse I’m guessing you have alot more hand than leg, which is causing him to hollow out, and either try to duck behind the bit to evade, or else push his nose into the pressure. Leg pressure would probably help that, but I wouldn’t experiment until you are with a trainer. As for speed control, that is a different issue altogether. Your pony is a talented jumper, and obviously moving a bit too fast and strong. I would think a good trainer would help you there, too. Control on the flat will help, but many good jumpers are too fast to be good hunters. Good luck and congratuations with what you have acheived so far!
Your information is incorrect, Aluminum has a very low fatigue limit. That is why the early Jet airliners has problems, such as the British Comet.