This thread is rockin' along pretty good! Let me clarify..
To all who posted about safety, I agree. When I start sliding, I mentally mark that place as one to avoid (I've got about 450 acres, so there are plenty of other places to play). But I routinely mow at angles greater than 20-degrees and don't slide on those hills. I've had to put a wedge under the tilt-meter to add 10 degrees in order to avoid burying it. Granted, I'm running a flail mower that's dramatically offset from center, have weight in all 4 tires, have the rear tires as far apart as they'll go, and always mow with most of the mower on the "high side."
For those of you who posted about the math, *that's* what's been tickling my brain. John's post about the rotation of the engine, vs the PTO, vs the mower is exactly what I've been puzzling.
Note: my bike has wheels that weigh about 3 pounds in rotation and they provide enough gyro to keep me (about 150 pounds) from falling over. My mower has about 1000 pounds in rotation, at a much higher speed. So I'm thinking it would have a fair amount of energy available to keep my (3000 pound) tractor upright. But I ran into that same equation that WVBIll posted and it made my head hurt.
Here's a site that helps get the math down to something I can handle. Note the last little bit where it talks about what happens when you double the mass, or rotation or whatever;
http://www.accs.net/users/cefpearson/gyro.htm
With regard to John's comment about the plane of the rotary mower -- my theory is that *both* rotary and flail mowers are oriented correctly to resist rolling motions of the tractor -- they're 90-degrees different (horizontal vs vertical), but they are both in the same plane from the gyro standpoint.
The tires are also in the right plane to resist rolling, but as the equation points out, they're rotating a lot slower so they offer less advantage.
I agree -- the *engine* (flywheel, PTO, etc.) isn't in the right plane to resist rolling.
