Do exmarks use a horizontal shaft? I heard that horizontal drive shafts sacrafice blade tip speed, is that true? What is exmark's blade tip speed? I have a Chopper but was wondering which mower has the higher blade tip speed.
Does anyone know at what RPM a dixie has a blade tip speed of 19000 fpm,as opposed to a Toro.I think that the Dixie gets its higher speed by simply governing the engine another 150 Rpm's higher than Toro/exmark/bobcat etc..If I look on the my mower,it says to maintain a minimum of 3500RPM's under a heavy load,and that for max performance-minumum RPM should be 3750-with no maximum listed.This is on the yellow sticker right behind the throttle and Tach on my Dixie Chopper.
Factors affecting blade speed that little include:
Slight differences in throttle/governer settings on engine
Heat/Moisture content of atomoshere
Engine tuning/air filter/carb cleanliness
Blade lift (yes, high lifts take more power)
Different blade lengths/pully combos need to leave room for some blade tip speed error
Deck size/engine HP ratio
What really matters is your blade tip speed when the grass is long/thick and that take engine power.
The deck on my 62" toro wb has a 8 1/4" deck pulley. Back when this deck was built (1991) the toro lit stated that the blade speed had been lowered to keep the noise level down. At 5 mph the lower blade speed is no problem.
With a new 62" (6 3/4" deck pulley) rider that can run 10 mph high blade speed is one way manfactures can get a decent cut.
Here's my 2 cents. I will assume that you are talking about ZTR's, as that is all that Dixie Chopper (DC) makes. Their gas engined models use vertical shaft Kohler, Kawasaki, and now Honda. The Diesel DC's use horizontal shaft.
Exmark Lazer HP's use vertical shaft Kawasaki's and Kohlers. Much like the DC design of a straight shot from engine to deck belt.
Exmark Lazers all full size regardless of gas or diesel use horizontal shaft engines. Kohler, Kawasaki, and Briggs. The deck drive belt goes through a mule drive that transfers power to the deck. They have been doing this since they invented the Lazer. I hope (for my sake) that they have perfected this.
As for blade tip speed, 18,500 or 19,000, I think we are splitting hairs here. The Exmark 60" and 72" decks do, without a doubt, cut better than a Dixie Chopper 60" or 72" deck. The differences in clearances between blade tip and deck baffles in both machines is amazing. On my old Dixie 60" I could get a finger between blade and baffle. On my new LC Lazer, they are within an 1/8" !! That is where Lazers get their air flow and suction. I had to scrape my DC every day, I only scrape my Lazer once a week when I change blades. BTW the blades stay sharper because of all the deck gauge wheels on the Lazer. I used to gouge the trim side of my Dixie all the time. Blades and dirt dont get along.
Don't get me wrong, DC's are terriffic machines that don't break (too much), however, they need to come up to modern times and improve the deck, enlarge the fuel tanks, and simply modernize what they now have.
I'm not sure that OSHA mandates blade tip speed. It may be OPEI or another one of those do gooder agencys.
As for OSHA, you better not let them near a DC!! They will take it away and put it in their museum of most dangerous machines. My new Lazer is real nice in the safety area. You can let it Warm up/Cool down without being on the seat. That was the main reason for removing safety switch on my Dixie. You had to be in seat to start engine. One butt scratch and the engine wanted to shut off. When its screaming at 3750rpm's and you take away spark for a second or two and then give it spark...wow thats good for an engine!!!