Interesting rotary bobweight setup for balancing (pictures)
Thread Starter
Senior Member
Joined: Jan 2005
Posts: 321
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From: Rancho Cucamonga Ca,
Interesting rotary bobweight setup for balancing (pictures)
I'm trying to figure out how to get 10+ lbs. of bobweight onto each rotor journal of the eccentric shaft. I tried using a single bob weight, but I could get 7lbs max onto them. I came up with the above idea, can anyone tell me if this will or will not work.
Thread Starter
Senior Member
Joined: Jan 2005
Posts: 321
Likes: 0
From: Rancho Cucamonga Ca,
51 views and no responses, come on guys. Spill the beans here, rotary engine balancing shouldn't be a black art. Spread the love.
On a more serious note though. I was looking at a video redline racing posted on youtube of them balancing a rotary. They are using what looks like a larger version of the bobweights used to balance piston engines. Here is a link to the video for you viewing pleasure.
http://www.youtube.com/watch?v=OfTpw4L9y4Y
From my understanding, the reason you can't use standard piston engine bob weights is that you can't stack enough weight on them. I tried and the most I could get onto one was about 7lbs. For the rotary engine you are looking at a minimum of about 10lb bob-weights so you have either get special bob-weights or hopefully you can just put two of them on the same journal. I first considered putting them parallel with each other, but then I thought that it would better simulate the rotors if I could set the two bob-weights 90 degrees apart on the same rotor journal like I did in the pictures above. I can't see anything wrong with this, but what do I know. I'm hoping I can get some opinions here.
On a more serious note though. I was looking at a video redline racing posted on youtube of them balancing a rotary. They are using what looks like a larger version of the bobweights used to balance piston engines. Here is a link to the video for you viewing pleasure.
http://www.youtube.com/watch?v=OfTpw4L9y4Y
From my understanding, the reason you can't use standard piston engine bob weights is that you can't stack enough weight on them. I tried and the most I could get onto one was about 7lbs. For the rotary engine you are looking at a minimum of about 10lb bob-weights so you have either get special bob-weights or hopefully you can just put two of them on the same journal. I first considered putting them parallel with each other, but then I thought that it would better simulate the rotors if I could set the two bob-weights 90 degrees apart on the same rotor journal like I did in the pictures above. I can't see anything wrong with this, but what do I know. I'm hoping I can get some opinions here.
I think you will need to go with some sort of custom bob weight. The ones in the video don't look that difficult to make. As far as spreading the love goes, how much did you figure the oil in the rotor weighs?
Can you test with one, test with both then compare the results? Would the amplitude of vibration at a certain crank angle increase with weight? If so then wouldn't that angle remain the same if your added weight is perpendicular to the position of the first weight?
I've never used the balancing equipment but I am curious...how do you calculate the overbalance weight given the rotor weight. What about oil clinging to front counterweight? If you neglect this added weight from oil won't this throw off the equation since the rear counterweight (built into the flywheel) rotates dry?
Is the flywheel and pressure plate added later and balanced?
I've never used the balancing equipment but I am curious...how do you calculate the overbalance weight given the rotor weight. What about oil clinging to front counterweight? If you neglect this added weight from oil won't this throw off the equation since the rear counterweight (built into the flywheel) rotates dry?
Is the flywheel and pressure plate added later and balanced?
