A new mower model "Mow All" coming soon...

[Egon]

Re: A new mower model \"Mow All\" coming soon...

Nomad:

Here is a very versatile mowing machince. Well reasearched and modified to perfection by many hours of emperical testing.

Egon

 

[ScottAR]

Re: A new mower model \"Mow All\" coming soon...

extensive field trials too.... /forums/images/graemlins/grin.gif

 

[Villengineer]

Re: A new mower model \"Mow All\" coming soon...

You mis-quoted me. I said that they must AT LEAST occur at the same time. There is an important difference. You're forgetting that the since the blade is on an axis and spends enough time over the grass for both ends to pass over it several times that the "lift" would be generated by the previous end of the blade. Being the fluids expert that you are, you know that the flow pattern would still be in action despite the fact that the end of the blade which caused the flow may be 180deg away.
</font><font color="blue" class="small">( I don't think the blade and deck are designed for recycling the clippings )</font>
For someone so interested in advanced tech, you sure are out of touch here. Like I mentioned in my previous post, there are whole lines of mowers designed specifically to maximize the recycling of the clippings. You can even purchase add-on kits to modify you current mower to do just this. They may have found this process on accident previously, but they definitely design it in now. Look at a finish mower blade, for that matter look at a 20 year old blade off a common push mower, they have a cross-section designed to create the flow paths you think are errors. Now take the decks from a 20 yr old mower and a new one. You'll see that they are designing in even more cavities and tunnels into the decks to maximize you so called mistake. Listen, the engineers and manufacturers of these products are experts in their field, you don't know more about it than they do so don't make the claim that they are lying to their customers to cover their mistakes. Besides, if it were the case, I'm sure you'd have seen this corrected years ago.
</font><font color="blue" class="small">( Yes, much sharper cutters will cost more, but don't forget many components of today finish mowers will be cancelled and such a simple finish mower with much sharper cutters with less number of components will cost much less than today's finish mowers which have many components )</font>
Mowers are fairly simple now and really don't use that many components. What are you going to do away with? I just don't see all these components you'll do away with.
Oh yeah, I just thought of another issue with your "mow-all". It will be a pain in the neck to use as a finish mower. If you've ever tried to manuever a rotary cutter of any kind you know that having an attachment that is roughly as long as it is wide is difficuly to use in areas that aren't wide open. I'll take the maneuverability of my multiple blade deck over your single blade deck any day.

 

[jinman]

Re: A new mower model \"Mow All\" coming soon...

</font><font color="blue" class="small">( Here is a very versatile mowing machince. Well reasearched and modified to perfection by many hours of emperical testing.
)</font>

Egon, I think we're on the same "wavelength." /forums/images/graemlins/laugh.gif

 

[nomad]

Re: A new mower model \"Mow All\" coming soon...

</font><font color="blue" class="small">( They may have found this process (recycling the clippings) on accident previously, but they definitely design it in now.. (..snip..) .. Now, you'll see that they are designing in even more cavities and tunnels into the decks to maximize you so called mistake. )</font>

I am not sure if we are understanding each other well.
To understand each other, let me ask this; why does recycling of clippings by the blade occur? or, in other words, why aren't clippings exhausted out of the deck after a single cut by the blade? or, in other words, what mechanism (action/flow/etc) under the deck is helping on recycling process? If we understand how recycling is occuring, then we can understand all about the finish mower. So, lets focus on this.

</font><font color="blue" class="small">( Listen, the engineers and manufacturers of these products are experts in their field, you don't know more about it than they do so don't make the claim that they are lying to their customers to cover their mistakes. )</font>

Listen - I am not questioning their details; their "this and that" emphirical parameters they have found. I'm questioning some basical things that may look complex things to you/many. You do not have to be a designer/manufacturer of a finish mower manufacturer to say that cavities/flow loops/attractors in a turbulent flow are almost impossible to design. If they already designed these, then I can say very very big number crunching super computers would not be spending months today to solve a simple turbulent air flow. Ps: I am a mathematical physics expert, rather than a fluid flow expert - and, I haven't used any technical term up to now in my posts although it may not seem so - Such things can be thought/talked about by anyone - you don't need to be a scholar. All people know turbulence is very irregular flow which can't be simulated so easily. Anyways. lets back to recycling process questions above in detail. (if any finish mower designer/manufacturer is/are out there, lets hear from them if they are lying or not about their mistakes (designing recyclings.)

Egon, this is a much better, real "mow all";-) (see attachment)
It can work like a rotary cutter, like a finish mower, like a boom mower, etc.

 

[Villengineer]

Re: A new mower model \"Mow All\" coming soon...

</font><font color="blue" class="small">( I am a mathematical physics expert, rather than a fluid flow expert )</font> And yet you made the following statement in a previous thread:
</font><font color="blue" class="small">( I have a PhD in mechanical eng. (turbulence in the fluids - experimental & computational) and have another PhD in theoretical science (mathematical physics - point symmetery groups and their applications to reduce dimension of turbulences&chaoses.) )</font> That's a lot of schooling in fluids to not be an expert if you ask me.
</font><font color="blue" class="small">( and, I haven't used any technical term up to now in my posts although it may not seem so )</font> So you consider Froude and Reynolds numbers casual dinner conversation? I know I don't.
</font><font color="blue" class="small">( lets hear from them if they are lying or not about their mistakes (designing recyclings.) )</font> Why should they answer your questions, you won't believe them anyway.
By the way there are plenty of companies modeling complex flow every day. I would be suprised if major mower manufacturers aren't among them.

 

[nomad]

Re: A new mower model \"Mow All\" coming soon...

You often said here "Nomad, you are a fluid flow expert, etc etc." Yes, I am also so - but I haven't followed that field from engineering point of view for a decade. I have looked at the fluid flow field as well as other continum fields from mathematical physics of point. I didn't say I wasn't a fluid flow expert, I said I was a mathematical physics expert RATHER than being a fluid flow expert, meaning that I am also fluid flow expert - but being a mathematical physics expert, I have a bird view ability on classical science. So, I can talk about the finish mower manufacturing too?;-)

Froude number was mentioned by Egon first and I only replied him reminding him of Reynolds number too. So, it was a casual, yes. Other than this talk with Egon, I have never used any technical term. I guess I have used a kind of language anyone can understand.

I am not expecting finish mower manufacturers to answer my questions - they don't have to convince me. I'm just trying to learn if they are really designing that recycling process of clippings and if they are doing it, how they are doing. Of course, I'll believe them if they tell logical things. If they tell me they are designing such a complex flow of air+grass mixture to cut one single very light grass blade several times in the deck (recycling), then I will really enjoy to hear how they are doing such a complex work. Maybe, they are using a statistical analysis only, who knows. All these are what we would like to learn here - so that we can understand they are really telling lie or not. I was also a farmer for 2 decades 1-2 decades ago and a hobby farmer now. So, they can consider me as a their customer. A customer is asking questions;-) so, they HAVE to answer. No?

 

[have_blue]

Re: A new mower model \"Mow All\" coming soon...

Nomad,

I think the next big advancements in mowing will be in metllurgy, not mechanics.

As you say, a sharp blade solves most all mowing problems. High mass, high HP, high RPM, rough cuts... all ubiquitous problems with mowing largely disappear when very sharp blades are used.

As we all know, a blade that is hard enough and abrasion resistant enough to retain a keen edge for 300' of mowing would be hard and brittle, and probably dangerous. Product liability insurance would never allow this commercially.

On the horizon (yea, I know it's long been promised) is amorphous iron. Amorphous iron is extremely hard and abrasion resistant, yet is not brittle at all. Unless the blades struck rock or sharp sand, it would retain an adge for a long time. The amorphous material could be layered mechanically or as a weld in a self-sharpening configuration on the cutting edge. I think it will revolutionize mowing, and perhaps make tiny robot mowers a practical reality some day. This is because thin sharp blades reduce power requirements dramatically.

While waiting for amorphous iron technology, I think a clever welder could develop blade technology using various hardfacing techniques. There are abrasion resistant HF alloys and compounds that are not brittle, yet very abrasion resistant. Self-sharpening configurations really work, and have not been seriously applied to mowing as far as I know.

Welp, gotta go sharpen my blades and get ready for the weeds! /forums/images/graemlins/smile.gif

 

[have_blue]

Re: A new mower model \"Mow All\" coming soon...

Nomad,

Just a few other things to chew on, as I think you are the type:

Sickle bar mowers are efficient and cut smoothly. Problem is, they reciprocate, which is a total waste of power, and high inertia is brutal on mechanical parts.

I can envision a bar type mower that has a continuous metal belt... like a big, agressive band saw blade. It would need fair sized drive rollers to keep the band from bending on too tight of a radius. It would require very little power. Even a tiny tractor could pull an 8 or 10 footer. Very low blade speed would keep the cutting edges sharp longer. Finish would be golf course smooth. Weeds, no problem. It could possibly even cut small bushes in low gear. Change the band for brush.

The enemy: Blade tip speed!

Just to show you how detrimental high tip speed is, try this. Sharpen your bush hog blades very sharp. Instead of running at normal 540 RPM, run at about 25-30%, and attack some light grass and weeds. You can mow slowly in a low gear, get a smooth cut, and the blade stays sharp for a surprisingly long time! Keep in mind that a soft lead bullet will deform steel if the velocity is high enough.

Some day we will find a way to make wear resistant blades, keep blade speed down, and mowing will almost be fun. Well, maybe not fun...

 

[rambler]

Re: A new mower model \"Mow All\" coming soon...

I have seen those continuos sickle bars for combines & such. They run on a roller chain. Very rare, but I see them as an after-market add on.

As to the muching mowers, nomad needs to do his research & look up replacement blades - should be able to find pics & specs on the 'net very easily. Those blades aren't all bent up into different lift angles just for fun or by accident! Of course people want lawns mulched, the clippings chipped up very small. That would be a requirement, and is a requirement, for a finishing mower. It is a design feature, not a mistake!

Research your market, nomad. You are trying to research the machine - that is pointless. You need to research who will buy it, and why. Then design the machine to do what people want.

They do not want one machine that sort of does all the multi uses. They want very good results from the machine they buy - either a good finished lawn from a small manuverable mower, or good hay quality that dries well, or to get a lot of rough grass & weeds & shrubs mowed down in a short amount of time.

Design & build your machine to what the market wants. Not an all-purpose machine that only does each job but poorly for each. No one will buy it.

--->Paul