# Does anyone know the Blade Tip Speed of the new JD X500 25hp/48" tractor?



## gmccall (Aug 19, 2006)

Hello,

I would like to know the blade tip speed of the new JD X500 with the 25hp 48" deck.

I called John Deere but they stammered around and then blew me off real quick...

Thanks!
Mac


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## JDFANATIC (Dec 28, 2005)

Mac,

It probably is a sore subject; there are Federal Regulations as to what speed the decks must be limited to. Where the area gets gray, is on commercial machines, and the defination of a commercial machine. I can understand the wish to pursue other topics . . .


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## DEERE180 (Jun 20, 2006)

Try basic physics: You KNOW the RPM of the motor/Rotor and you know the radius of the blade...so there you go!


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## ducati996 (Dec 27, 2003)

I would think the pulley(s) would have the biggest effect no ?


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## Live Oak (Dec 22, 2003)

477.9253 feet per second! cruisin :nerd:   Just kidding. That will very likely be a tough number to find as I have never seen this information made available in the technical specs. of most owners manuals and such.


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## John-in-Ga (Sep 22, 2003)

This is not quite what you are looking for, but could be a step closer to finding the answer to your question. Granted the calculator is for aircraft propellers, but as DEERE 180 suggest, basic physics is basic physics. 

You will need to know blade rpm. If I’m not mistaken the engine speed of your JD X500 is listed in your owners manual. With that and the measurement of a couple of pulleys you should be able to determined blade rpm.

You will need blade diameter - an easy measurement. 

You will need Ambient Temperature (deg. F). Check local TV channel. 

Now go to this link and where it says “propeller” read “mower blade”. 

Propeller Tip Speed Calculator

Your result should be something approaching 200 mph.


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## gmccall (Aug 19, 2006)

Thanks Guys,

And thanks John-in-Ga, I'll give this a go.

I'll report back to you all on this as soon as I get to it. Maybe in a week or two. 

Still waiting for my X500 to get delivered...

Anxiously,
Mac


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## Chris (Sep 15, 2003)

What was the reason for the need to know about the blade tip speed on your deck?


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## gmccall (Aug 19, 2006)

Dear Admin,

Well, blade tip speed is now becoming another indicator of grass cutting performance in many situations. Consumners are getting smarter about certain specs, and this is one of them. Now it is growing as a specification consumers are looking at. Some machine makers are even advertising this spec now.

Of course it all has to do with power and speed related to cutting performance.

There are many variables associated with the calculation, but that does not hold me back from my interest in this as a specification of interest.

I am not mathematician or engineer, but my "mechanical sense" tells me that slower spinning blades do not cut as well as faster spinning blades in most situations, when directly related to torque and horsepower.

Best Regards,
Mac


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## HYDROGUARDIAN16 (Feb 14, 2007)

fast enough to chop off your leg.:starwars:


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