View Full Version : BLADE TIP SPEED !!!!!!!!!!!!!!
02-01-2001, 06:42 PM
I'm running a Walker MT-54 gear-drive deck, can anyone tell me what blade tip speed I might be running? Engine size is a 20HP Kolher Twin. Do belt drive decks have more tip speed and WHY? Thanks for your input.
AB Lawn Care
02-01-2001, 06:53 PM
Sorry I can't tell you what the blade tip speed is but I can tell you that the walker 54'' gear driven deck has a better cut than the belt versions.The only draw back is the gearboxes can bust if you really hit somthing large.Blew on apart when I hit a large stump in long grass.It was my fault though becouse I knew better.I should have took in my belt drive scag first.Some people have flamed that deck becose of the gearboxes,but if do take it easy and don't risk it,then you will do alright!
02-01-2001, 06:58 PM
Shpuld be 18500.according to spec..
02-02-2001, 12:25 PM
Isn't the maximum allowable tip speed 200mph? I seem to remember reading that as a standard for the industry.
02-02-2001, 12:32 PM
I have heard 19,000 feet per minute is the limit, which is 215 MPH.
02-02-2001, 02:28 PM
To convert feet per minute to miles per hour, multiply by .01136. Eric is correct. That comes out to 19,000 X .01136= 215.84 mph. At 18,500 X .01136 we arrive at 210.16 mph. Obviously, there is very little difference in blade tip speed once you approach the legal limit. I have yet to see a <b>new</b> ZTR with blade tip speed listed below 18,000 fpm. I know for sure the older Toros were slower than that, though.
Now a mower with 16,500 fpm blade tip speed would only be traveling 187 mph. There would likely be a noticable difference in quality of cut at high speeds with this slow a blade tip speed.
I've read all the calculations for blade tip speed, but how do you increase blade tip speed? Is it possible?
Also, does anyone know the blade tip speed of a Ransomes Bobcat ZT219 19kaw 48" deck?
Either increase rpm or ratio.Either is taking a chance.
They dont give these things away
03-26-2001, 09:47 PM
If the blade speed makes such a difference in cutting performance then why do companies do any other speed than the max allowed?
Eng Mwr Guy
03-28-2001, 02:17 PM
The max is 19K feet per minute per ANSI. Which can take a railroad spike and throw it 200 yards through a window...keep those discharge chutes on please!
This has to be for EVERY mower produced. Therefore, most manufacturers stay well under the specification in order to avoid the variance in manufacturing from engine manufacturers.
Faster is not necessarily better. It sometimes just is that way in our mind.
There are many factors affecting quality of cut. Blade speed is only 1.
03-28-2001, 03:27 PM
Currently I do not own a Dixie Chopper, but am planning on purchasing one once the cash flow comes in. Correct me if I'm wrong, and that's often, but isn't the DC'S blade tip speed like at 19,800 standard, that's what it says at there website anyways. The Dixie dealer told me that once he gets them in, he cranks the RPM's up to get even faster B.T.S.. If this is the case, how do they get away with it, knowing that the standard model exceeds ANSI regulations. Just a question that I have wondered for some time.
03-28-2001, 03:42 PM
turfguy33, looked up on the DC website on the specsheets for the mowers and it shows the blade tip speed at 19,000 ft per min. I looked at several of the models listed and they all showed 19,000 fpm. Go back and take another look, if you find one that is over 19,000 let me know which one it is.
Eng Mwr Guy
03-28-2001, 03:45 PM
I would guess it is a blood from stone thing.
What do I mean:
Rock flies out
Kills person....actually maims them that is worse from money standpoint.
Jimmy is now maimed for life. Can't work. Traumatized...etc.
Jimmy sues for damages. Jimmy could have been a Doctor if it wasn't for this accident. Blah, blah, blah.
Jimmy goes to court against DC. DC says sorry we are out of business....or says we had no knowledge of what our dealer did. Dealer denies all knowledge.
Jimmy gets nothing.
Now if you replace DC with Toro, Scag, or any larger asset base company they have more to lose.
At Ariens/Gravely, as much as I would like to recommend replacing pulleys to increase blade tip speed and cut with 2 blades at this time, I can't because we follow the ANSI regulations because it is deemed safe to do so.
If people are putting their altering of equipment in writing they are exposed to lawsuits and are not, in my opinion, building safe equipment.
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