PDA

View Full Version : 20,000 FPS blade-tip speed = BULLCRAP!


topsites
10-07-2010, 08:24 PM
I hereby call all lawn mower manufacturers, dealers, advertisers and anyone else
who is blithering off this insipid nonsense full blown LIARS!

Why, because...
According to an FPS - MPH converter, 20,000 FPS = 13,635 MPH!

LOLololol omg they have been feeding it to us SO thick!

Thirteen thousand miles per hour ...
The speed of sound is only 768 Mph~!

I should be hearing the SOUND BARRIER Breaking every time I engage the blades!
Several times over, the blistering speed of the tips of my mower's blades should be
hitting that sound barrier Ka-BOOM -- Ka-BOOM -- Ka-BOOM -- Ka-BOOM !!!
But, no.

Heck yeah the speed of light is only 186000 miles per hour, according to these folks our lawn mower blades are zipping along at
about 6% of that, which may seem slow but it's still faster than most rocket ships and satellites currently in space lol maybe
they should be using lawn mower "blade tip speed" technology in the space shuttles of the future.
Then again maybe they did.

As you can see I was very bored at work today.
But seriously, how can they get away with this kind of *(&%^!?

Is it just me or do they really think of us as stupid?

deerex
10-07-2010, 08:32 PM
I believe they measure in feet per minute. Fpm

topsites
10-07-2010, 08:38 PM
I believe they measure in feet per minute. Fpm

Ohhhh, dang.

13 635 / 60 = 227.25
Well, that's not so amazing anymore.

rain man
10-07-2010, 08:43 PM
Welcome back topsites.

deerex
10-07-2010, 08:50 PM
Not trying to hijack your thread but it might distract people from your brain fart. Just kidding ya. I was wondering is around 18000 fpm like the perfect blade tip speed or what. It seems like that is where every manufacturer is at. In my simple mind it would seem like more would be better.:drinkup:

Hawkshot99
10-07-2010, 08:56 PM
Not trying to hijack your thread but it might distract people from your brain fart. Just kidding ya. I was wondering is around 18000 fpm like the perfect blade tip speed or what. It seems like that is where every manufacturer is at. In my simple mind it would seem like more would be better.:drinkup:

I believe that is what OSHA dictates as the top speed.

deerex
10-07-2010, 09:05 PM
I believe that is what OSHA dictates as the top speed.

That makes sense. Man with the way old UNCLE SAM keeps taking over our lives more and more with rules and regulations this and that I would not be surprised if they would drop that # to about 2000 fps LOL

fatboynormmie
10-07-2010, 09:22 PM
ohhhh, dang.

13 635 / 60 = 227.25
well, that's not so amazing anymore.

oh dang lmao

integrityman
10-07-2010, 09:28 PM
I believe top end blade tip speed is an ANSI governed policy. I think Dixie Chopper is rated at the highest fpm blade speed at or around 19,00 fpm...gimme a minute to check dixies web site.

StanWilhite
10-07-2010, 10:32 PM
I hereby call all lawn mower manufacturers, dealers, advertisers and anyone else
who is blithering off this insipid nonsense full blown LIARS!

Why, because...
According to an FPS - MPH converter, 20,000 FPS = 13,635 MPH!

LOLololol omg they have been feeding it to us SO thick!

Thirteen thousand miles per hour ...
The speed of sound is only 768 Mph~!

I should be hearing the SOUND BARRIER Breaking every time I engage the blades!
Several times over, the blistering speed of the tips of my mower's blades should be
hitting that sound barrier Ka-BOOM -- Ka-BOOM -- Ka-BOOM -- Ka-BOOM !!!
But, no.

Heck yeah the speed of light is only 186000 miles per hour, according to these folks our lawn mower blades are zipping along at
about 6% of that, which may seem slow but it's still faster than most rocket ships and satellites currently in space lol maybe
they should be using lawn mower "blade tip speed" technology in the space shuttles of the future.
Then again maybe they did.

As you can see I was very bored at work today.
But seriously, how can they get away with this kind of *(&%^!?

Is it just me or do they really think of us as stupid?

Hey TS...think you missed the speed of light ever so slightly too. It's aprox 186,300 miles per SECOND.....not hour! :-)

DA Quality Lawn & YS
10-07-2010, 10:40 PM
Thanks topsites, this thread is a hoot!

Blades spinning at the speed of sound, now that is something!

Lbilawncare
10-07-2010, 10:52 PM
Which is heavier? A ton of bricks or a ton of feathers.

Jay Ray
10-07-2010, 11:08 PM
Thanks topsites, this thread is a hoot!

Blades spinning at the speed of sound, now that is something!

Engage the blades and break windows with the sonic booms:laugh:

kilgoja
10-07-2010, 11:35 PM
i think if they went that fast you would fly straight up in the air when you turned the blades on

MOturkey
10-07-2010, 11:56 PM
Toppy, where have you been man! We missed you!

rain man
10-08-2010, 12:33 AM
Is the 18,000 fpm the optimum...as under labratory conditions...perfect temperature, perfect humidity, flat blades, sitting on pavement, etc? Or is this number reflective of what you can expect in the field?

MJS
10-08-2010, 12:59 AM
i think if they went that fast you would fly straight up in the air when you turned the blades on

I hate how effective modern high-lift blades are getting.

mbrew
10-08-2010, 07:18 AM
Is the 18,000 fpm the optimum...as under labratory conditions...perfect temperature, perfect humidity, flat blades, sitting on pavement, etc? Or is this number reflective of what you can expect in the field?

The better blade manufacturers test their blades for damage during impact and they need a standard to test against. For whatever reason ANSI (an institute that sets standards) selected that speed. My guess is that it gives good cutting performance, is easily attainable with most engine setups, most bearings can handle that speed etc. I'd also bet that it has something to do with thrown objects.

OSHA often requires items to meet ANSI standards, safety glasses for instance, but I don't know if OSHA has anything to say about blade speed. Many of these standards are voluntary for compliance.

bel-nor
10-08-2010, 08:02 AM
FPM is probably estimated in relation to all three blades processing at the same time, not one blade totaling say maybe 5500- 6500 FPS. The sound and experience of operating a new JD 7h17 (first commercial mower) showed me there is a big difference in what is claimed to be a commercial product and what really is. Oh yes it felt like it was going to hover off (over) the ground.

integrityman
10-08-2010, 08:24 AM
Here is some good reading. Im always curious why ALL manufactures dont max out blade tip speed.....

http://70.85.43.66/showthread.php?t=221990&page=3

cgaengineer
10-08-2010, 08:31 AM
Funny thread!
Posted via Mobile Device

Hoy landscaping
10-08-2010, 09:11 PM
Ahh so glad i blocked TS

MR-G
10-08-2010, 09:20 PM
I am pretty sure that the max blade speed on any commecial mower is in the area of 3600-3900 rpm....not to say it cant be increased....but why? should you hit something solid the damage to the machine would be extensive..would also change the lift....

Roger
10-08-2010, 09:30 PM
... sure glad LS contributors are not design engineers for the OPE industry.

Whew! So much wrong here ....

topsites
10-08-2010, 10:07 PM
... sure glad LS contributors are not design engineers for the OPE industry.

Whew! So much wrong here ....

Oh yeah hahaha I made a mistake but don't get me started on what's wrong with the new Toros,
now it takes a city farmer to fark up a blade tip speed but I'm telling you it takes some master degrees
in engineering at the factory to really foul it up LOL.

That having been said this thread is right embarrassing to me but you know...
You ever wonder how many dumb things any one of us has said to a customer when,
in all honesty we thought we were dead on right? :p

Good thing I tested out this blade tip speed conversation here.

Ahh so glad i blocked TS

So that means I can insult you and you won't see it, right?

ALC-GregH
10-10-2010, 10:10 AM
I am pretty sure that the max blade speed on any commecial mower is in the area of 3600-3900 rpm....not to say it cant be increased....but why? should you hit something solid the damage to the machine would be extensive..would also change the lift....

I'm SURE you are wrong. You're speaking of engine RPM which most all manufacturers have them set at 3600RPM. Blade tip speed is determined by the engine RPM and drive pulley size. These figures are where the FPM are figured on how much grass can be cut by the blade in a minute.

Clark Griswold
10-10-2010, 01:54 PM
My blade speed is just prefect, it cuts the grass!

flatlander42
10-10-2010, 05:22 PM
Bump!!! haha

Richard Martin
10-10-2010, 06:49 PM
I believe top end blade tip speed is an ANSI governed policy. I think Dixie Chopper is rated at the highest fpm blade speed at or around 19,00 fpm...gimme a minute to check dixies web site.

You're right. 19,000 FPM is an ANSI requirement.

Dixie's used to come with some truely hair raising BTS. If you turned the engine up to their recommended 3800 RPM you were getting close to 22,000 FPM on one or two models. Mine is around 21,000 FPM at 3750. The new Dixies have all been whimped down to below 19,000 FPM.

Runner
10-11-2010, 11:43 AM
I'm SURE you are wrong. You're speaking of engine RPM which most all manufacturers have them set at 3600RPM. Blade tip speed is determined by the engine RPM and drive pulley size. These figures are where the FPM are figured on how much grass can be cut by the blade in a minute.

This is so true, Greg. Another reason why the smaller decked mowers, such as the 48's and 52's, have to have faster turning blades (rpm wise), to equal the same blade tip speed. :)

TNGrassCutter
10-11-2010, 11:47 AM
i think if they went that fast you would fly straight up in the air when you turned the blades on

yea you could put your high lifts on upside downand fly to your next lawn

grassman177
10-11-2010, 12:56 PM
You're right. 19,000 FPM is an ANSI requirement.

Dixie's used to come with some truely hair raising BTS. If you turned the engine up to their recommended 3800 RPM you were getting close to 22,000 FPM on one or two models. Mine is around 21,000 FPM at 3750. The new Dixies have all been whimped down to below 19,000 FPM.

i have never cut with or seen a dixie cut, is that very high tip sspeed really making a difference in quality of cut, or is it to keep up with the ablity of the machine to be the "fastest lawn mower"

Richard Martin
10-11-2010, 03:29 PM
i have never cut with or seen a dixie cut, is that very high tip sspeed really making a difference in quality of cut, or is it to keep up with the ablity of the machine to be the "fastest lawn mower"

I've never used another brand of 60" mower to compare it to. I'm very happy with it's quality of cut in both northern and southern grasses. My deck just doesn't handle crabgrass well but I've always said that.

Patriot Services
10-11-2010, 04:30 PM
LS is full of Wiley Coyote super genius types! Convinced that bigger and faster is better.
Posted via Mobile Device

grassman177
10-11-2010, 04:34 PM
i dont think any deck handles crapgrass well! i did however think that tunnel decks do better on it.