Stock Appearing Race Saws

[Mr.]

This is just more of the same old BS. Opinion stated as fact.

I'm glad you noticed a gain TW. Keep on doing what is working for you. I'll do the same, but without trying to convince people my way is the best way or only way.

Input is always welcome, but keep that judgemental BS to yourself.

Fred

 

[buck futter]

"Maybe I can get some discussion going by talking about them as the main topic."

Fred

I was hoping for some good discussion too. I have did to stimulate some talk, but it doesn't seem to be working so well. What did you have in mind, lets start over, lead the way Fred.
I like Frank and Brian shooting holes in the theory. I don't mind showing stuff for people to critique, I don't mind being wrong or admitting I am wrong if I end up being faster because of it.


Buck

Lets all show someting we are working on, I have already showed a cylinder that I need to cover up some holes.

Doug why don't you show us some pics of what you have been doing even the intake mod to your 7900.

 

[Mr.]

Did you punch those holes?

Those are some big ones.

Fred

 

[buck futter]

nope

Ice cream scoop with a carbide tip.
I made them a little bigger for better filling.

I have the saw with very low porting right now to break it in. Its really a great firewood saw right now.

then it will be a little more duration, a little less squish clearance,I'll slap on a carb and finish it off with the well timed bowtie.

Then it will be off to the logstand to make some cakes and pies, mmm cakes and pie.


Buck

 

[Stihl Crazy]

So do you have any pics of marcel saws? Or do you have any marcel saws now.
Buck

I have 1 Marcel saw. My 166, it has a full flywheel.

 

[buck futter]

Thanks Art,

honestly I can't believe he would leave those alone, I would love to find his reasoning.

Art does that saw have a head or external ports or holley 4bbl on it?

Buck

 

[Mr.]

Thanks Art,

honestly I can't believe he would leave those alone, I would love to find his reasoning.

I already stated what Marcel said. Maybe I forgot to add it was him who said it.

1. balance
2. no noticable gains (per his testing)
3. "Who needs cooling? Baby I need cooling."

Fred

 

[timberwolf]

I thought you were dropping this when you were implying each to their own... I was fine to leave it at that, but keep in mind you have kept chewing on the bone, yet accuse me of the "same old BS".

If you got something thats working for you, great, it's not consistaint with what I have found, so what makes for interesting discussion. Maybe you have found a perpetual energy principal, just take a very tiny motor and drive a fan with it, as it takes no energy to drive a fan based on your saw observations then we should be able to mount a wind mill in front of it get enough power to drive the little motor off it and sell excess power to the grid.

When I get the time I will put some proof out on the implications of the fan and heat build up, but I am not going to waste energy in blowing hot air about it.

 

[Mr.]

I thought you were dropping this when you were implying each to their own... I was fine to leave it at that, but keep in mind you have kept chewing on the bone, yet accuse me of the "same old BS".

Buck asked a pointed question and I pointedly answered it.

My objection was with your implication that it was ignorant or in folly to leave a flywheel whole.

On the instant replay......
Joe asked a pointed question and I pointedly answered it.

Fred

 

[Mr.]

If you got something thats working for you, great, it's not consistaint with what I have found, so what makes for interesting discussion. Maybe you have found a perpetual energy principal, just take a very tiny motor and drive a fan with it, as it takes no energy to drive a fan based on your saw observations then we should be able to mount a wind mill in front of it get enough power to drive the little motor off it and sell excess power to the grid.

When I get the time I will put some proof out on the implications of the fan and heat build up, but I am not going to waste energy in blowing hot air about it.

Make a new thread and I'll be there with a pin........

Fred

 

[drmiller100]

it sure is nice to be loved.

it is also interesting how rude some people can be when they doubt you will ever meet them in person.

So i have a 1/3 horsepower fan sitting over in the corner. it blows a fair amount of air. a LOT more air then my chainsaw blows out at full chat. we can do all the math we want, but when all done some common sense can be kind of interesting.

as for pics, send me a camera, and i'll click and return it. or be patient, or shut up, or feel free to continue being the ignorant twits you are.

 

[Mr.]

as for pics, send me a camera, and i'll click and return it. or be patient, or shut up, or feel free to continue being the ignorant twits you are.

Can we be patient and not shut up? j/k

Fred

 

[Danger Dan]

it sure is nice to be loved.

it is also interesting how rude some people can be when they doubt you will ever meet them in person.

You should know. opcorn:

 

[timberwolf]

Amazing how sensative people get when anything is questioned.

There may only be one single fact in life, and that is "That there are no facts, even what we take to be fact is only but opinion or preception of what people observe. Some opinions are generaly well accepted, other are not."

As for the fan on a saw I would say there is a good bit of air coming off it, remove the cover, rev it up and it is a significant breeze. Just a couple points I have in my mind, a plug in fan turns ~ 1700 RPM and the outer edge of the blade moves about 60 miles an hour and creates a wind velocity of about 10 mph or so. A racesaw fan is turning 10 times that speed and the outer edge is moving 5 or more times faster. Both friction and the energy of air movement go up exponentially, Friction on the square, wind energy on the Cube (doubling the wind speed = 8 times the energy). So #1 the efficency of the race saw fan is going to be drastically lower, and #2, though it generates a smaller volume of air that air is moving much faster it contains a lot more energy (volume to volume) than the slower air from a plug in fan. A good example of this is power output on a wind turbine.

 

[timberwolf]

Doug, thinking about what you said, your 100% correct your plug in fan does move a LOT more air than your chainsaw, but I am questioning the amount of energy that air movement contains do to the difference in velocity between the two.

I have 5 HP 220 volt air compressor, and I would say your 1/3 hp fan moves more air too. A 1/3 hp circulation fan can easily move 5,000 to 10,000 CFM, a 5 HP compressor less than 20 CFM. The compressor moves only a few pecent of the air a fan does though it takes 15 times the energy. Just saying there are other factors to considder. Even once you considder the pressure difference and multiply the compressor volume by 10 atmoshperes your still only moving about 200 CFM.

 

[drmiller100]

fred, my post wasn't directed towards you at all. sorry it came across that way. you have certainly helped me a lot, and I always learn from your posts.

tw, ultimately, horsepower gets turned into one of two things. either work done over time, or heat.

your 5 horsepower compressor accomplishes work by compressing the air. the compressed air is stored energy. during the process, you get a small byproduct of that compressing of air in the form of heat. feel the top of the head, and you know how much heat that 5 horsepower compressor can generate.

the air coming off the fan itself of the chainsaw has no heat. the air is not compressed, and really there isn't very much of it either.

we can argue somewhat about whether the velocity is a function of the square or the cube of the horsepower, but we there is NO argument that the diameter of the fan squares the amount of air pumped.

if you are really curious, put an electric fan on a flywheel, spin it up, and measure the watts at 13,000 rpm. i really bet it isn't very much. a 1/4 horspower i would believe, half i would be very suspicious of.

 

[timberwolf]

I do agree that the compressor is an extreme example, and that is exactly why I chose it. In that case it takes a huge amount of power to push a small amount of air out a very small area at high velocity in a very inefficient way, where a simple fan turning at fairly low RPM moves much more air but much slower and more efficently. The fan on a chainsaw is going to fall somewhere between these extremes.

tw, ultimately, horsepower gets turned into one of two things. either work done over time, or heat.

Yes so does an electric fan, except we measure the work it does as kinetic wind energy. Air has mass and it takes energy to move it, the faster we move it, exponetially the more energy it takes to move. So infact one of the saws work outputs is moving air. Then given the output of a saw is finite, if we can reduce the work component of moving air there is then greater net energy availible for moving the chain. "A dollar saved is a dollare earned".

Work by definition is "(physics) a manifestation of energy; the transfer of energy from one physical system to another expressed as the product of a force and the distance through which it moves a body in the direction of that force; work equals force times distance."

You can argue about the energy in moving air if you wish, but go do some reading on wind turbines specificly power output curves based on wind velocity. But I don't see there is much to argue about.


If we all were in total agreement, there would be nothing to discuss and it would be dull indeed.

 

[buck futter]

"where a simple fan turning at fairly low RPM moves much more air but much slower and more efficiently."

So TW is this the same theory that a larger base works on?


Doug, All of the energy you are talking about goes to heat, it is just a matter of when.


So If I take the flywheel in the previously posted picture and do one cut with the stock flywheel and one with the modded one the proof would be evident in two ways.

If nothing else is touched then the wot rpm should increase.

Will the increase in rpm tell us how much power was released?

If I do a cut or three with the stock flywheel and one with the modded one
will there be a difference in cut times and in the wood rpm?

Buck

 

[timberwolf]

Velocity of the charge is an issue with ports, But I don't think I would say it is the main issue with a larger base, however a larger base and larger ports with lower velocity will meet less resistance to flow. Problem I see is too big on the base, intake and transfers and flow becomes lazzy, scavenging is hurt, so is lower RPM torque.

Yes, you can switch one stock fly wheel to a modified flywheel and see for your self, only thing I found you need to watch is the timing, seems it can be different by a couple degrees from one fly wheel to the next also how tight the key is, if there is slack on the key/slot the flywheels could be put on a couple deg different and that would may effect the results.

 

[24d]

if a electric fan had four blades an you removed two of them would it then take less energy to turn the fan than with four blades-I cant get the why's and cause thing--just give my simple mind a yes or no