cast flywheel explosion

At a local fair pull this past weekend, I saw cast flywheel explosion - had to be one of the top 5 scariest things I"ve ever seen live in my life. I know I"ve heard it said that this could happen, but until I saw it live and in person, I never imagined how much force is involved with it! In the 8,500 pound pace class, the driver of a Case 930 was pouring it on at the end of the pull when the flywheel exploded and literally sawed the tractor in half at the bell housing. Thankfully, the tractor was equipped with a scatter blanket or there would have been a massive blood bath, but there were still several pieces that escaped as the tractor partially collapsed on itself and the blanket pulled apart. I"d say 90% of what escaped went to the left side of the tractor. About half of the pressure plate ended up in or near a goat pen in a barn about 100 feet from the tractor, and another piece of roughly 4-6" diameter cast apparently from the bell housing ended up on a fair road probably 200-250 feet away from the tractor. Several springs from the pressure plate and other small pieces of cast went away from the tractor as well, and I heard that one lady went to get a few stitches in her arm. My uncle, who was standing at least 50" away from the tractor, was hit in the side by the largest piece to escape - a 12 pound piece of bell housing that pealed out from the front of the blanket and probably never got higher than 6" off the ground on a b-line... and I"m sure it was slowed down partially by the blanket as the blanket was completely covering it before the explosion. The piece hit him, and then bounced back 10-15" towards the tractor. He goes probably around 350 pounds, and he went down like a deer that had just been shot (I was the next puller and he and my dad had just gone down to watch). To make this part short, I left with him in an ambulance, and everything ended up checking out okay - he"s just going to be sore for a while. Luckily the round of the inside of the bell housing is exactly how it hit him and distributed the blow over a larger area - had it hit any other way it would have done much more damage. The doc said had he been a 150 pounder, he probably would have had a lot of internal damage.

For those of you that run over stock RPM"s (and maybe even if you don"t) - here are a couple of notes that we"re going to consider on everything we pull:

1. The scatter blanket literally saved several lives in this situation and many serious surgeries, etc. - no doubt in my mind. Not only the lives of the spectators, but also of the driver. It was the only thing holding the tractor from totally collapsing on itself - if it had, the driver would have been crushed by the steering wheel and seat coming together (when they pulled it off the track, it eventually did collapse totally on itself). The $350 it costs that seemed so overpriced last week seems like a bargain this week.

2. A tie bar from the engine to the transmission would make the scatter blanket more effective so that the tractor doesn"t collapse on itself and pull out from under the blanket (would also help save driver in event of collapse). I know this is in rules for stuff “bigger” than antique, but wouldn’t hurt for us either.

3. Side shields need to be built for more than just decoration - they need to be able to stop stuff from leaving the engine compartment. (the piece that hit my uncle blew the back of the side shield off like it was a piece of aluminum foil),

4. A steel flywheel when running over stock RPM"s is necessary. I wouldn"t have believed it until this happened, but the part of the flywheel under the ring gear(steel) did not explode - it was intact. Everything that was steel was either intact, dented, or torn, but nothing steel shattered.
I know locally that this event is already serving as a huge wake-up call, and will direct the way that rules and enforcement will take place in the future. Unfortunately, there will be a lot of fingers pointed at the kid who owned the tractor this happened to, and he"ll end up the poster boy for pulling safety and "the kid who wrecked if for the rest of us" as I"ve already heard mentioned. The fact of the matter is that there are dozens of tractors running around locally with more power and less protective equipment than the one that blew. He’s an anxious young puller who wanted to get onto the scene with something competitive. He did so, but he was also handed a time bomb when he bought the tractor and it happened to go off on him. He was in the process of getting a steel flywheel, and things didn"t come together for him in time so he put it together to go to the biggest local pull around. If we were honest with ourselves, most of us have cut a corner or two to make it to a pull, and I’m not sure we’d have done anything differently (you know – it’s made it down the track 500 times before, it will surely make it another 3 or 4 times…..). I know from now on, it will be a lot harder to cut those corners in light of this happening.