Well, I'm not trying to get anybody PO'd. I'm just asking a question. Really, I have no desire to upset anybody. While Scott231 may be a long standing member, and have a lot to contribute, I have only really noticed his input on this thread. So the only thing I know about him is what I have seen here in the last 2 days. It's a first impression. Be that as it may, I'm not looking for a fight, just an honest opinion. I'm kinda like a 2 year old. "Because" has never satiated me.
I looked at the photos on the DOTCC on ttype.org, and while the pictures are pretty fascinating, it is hard to tell exactly how the crank failed. There are ways to describe a failure.
Let me take a minute to try to explain why I keep asking what appears to be such a pig-headed question:
The reason my curiosity is piqued on this is that the general consensus is that the rolled fillet cranks are stronger. However, cold rolled fillets are a means of introducing stress into a surface, which helps to minimize cracks forming and is a means of increasing fatigue life. Fatigue life is a duration thing, and relates to how long a part is expected to last (number of cycles) under a given load.
I asked a mechanical systems professor (he is also a PE) how the fillets increase ultimate strength. He thinks it has little to do with the ultimate strength of the part, and much more to do with the fatigue life. In fact, he thought the slightly smaller diameter of the rod throws on the crank may have an adverse effect on the ultimate strength of the part, but that would have to be measured to really know. He also said that the greatest stresses on a crankshaft will be concentrated on the main journal between the rod and the crank throws.
Anyway, if such is the case, it might be a much wiser allocation of funds to go for a girdle and/or billet main caps to prevent crank flex at the mains. Of course, this is only an idea. But everything starts somewhere. So, I asked about it.
Anyway, sorry for any ruffling of the feathers, but I don't really think it right to insult someone for asking something. I am a student, I am in my mid 20s, and I do have a lot to learn. But, I'm also very mechanically incliuned, I have built a couple of engines, and I have fixed a lot of problems on a lot of different systems, both mechanical and electric. I'm here to learn as I build up my GN drivetrain. I just like quantifiable information.