Micro Vibration & a little more.

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
Post Reply
User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3344
Joined: Sun Feb 13, 2005 1:00 am
Location: rockfalls, Illinois

Micro Vibration & a little more.

Post by sporty »

I have been a firm believer, that one of the losses of energy / speed in a pinewood derby car. Was micro Vibration.

I use to talk to a few racers, at length about it and Some of my theories and ideas were put to the test and did seem to prove my theory on it.

I wont name names. I'm gonna avoid that.

But I will toss out a few of those theories and experiements. some I completed. Some I did not.


1. A wooden track doews absorb more vibration than a metal track. However. A wooden track has a much ruffer surface, than a metal track.

But even a metal track stock out of the box, can be improved.

A metal track. Polishing the track surface, makes its slicker. and will improve microvibration. And the overall times on the track will decrease. (meaning the cars with be a tad faster) after you polish and buff out the aluminuim on the track.

A wooden track, this is much harder to due. You could super sand it. then seal it, ect. But a even coat of sealer or ect on it. Still very hard to make even and smooth. When looking as a micro based level.

Now-

One of the things I spent time tinkering with, was various rubber as a damper for reducing micro vibration.

Now, lets set aside, that when you are looking for the last bit of speed out of your car and you current abilities. Only then do you look into tinkering to such a degree.

Meaning, if you are a novice. there is no real point for you to try this. Futher more, if you lack a track and timer.

So I hope you gather what I am saying, when you can go no faster, you start looking at the smallest things to get a tad bit more of speed. very few reach this level, when keeping a cub scout and scout race in mind.

So it's just not a whole lot practical.

So back on track here, with that brief mention.

I took, rubber and hard rubber and I basically drilled larger axle wholes and inserted the rubber and then drilled out the axle whole into the rubber.

I also tried small square pieces of rubber, inserted and drilled out the axle whole.

I tried partial amounts of rubber with only a small amount touching the axle.


Trial and error's.

Trying to drill rubber and not have a bad axle whole. Hard to do ! the rubber wants to mess up the whole and come out as you pull the drill bit back up, in such a way, that it wrecks the axle whole.

Then, ughh. I finally had a few designs and types, that works. woohoo, break thru. right ?

Kind of sort of. while I saw times drop a tad. which thats all I was looking for was any kind of drop in times.

I encountered issues, of the forward motion and downforce effecting my alignment. The rubber was just a tad to soft to hold my alignment like it's suppose to.

Went to a harder rubber and it did not absorb the micro vibration.


I tried many different things, softer plastic, ect.

I was getting closer though and had a few more things I wanted to try, before I called it quits.

I wanted to try the plasti dip and rubberized coating on the axle itself and I was even wanting to try the sound absorbing paper and wrap the axle around it and see how it did.

But I just never got to doing all the things that I wanted to do with it.


Also during this time, I played with different tpyes of wood.

Mahagony, birch, popular, oak and another type, I forget that one. then the sugar pine, soft pine. standard pine, balsa.


I did find, some of the wood, did not help with micro vibration, it made it worse. it did not abosb it, it caused the vibration to bounce right back onto the axle / wheel.

I can tell you, that a denser wood is the wrong way to go. a stiffer wood is the wrong way to go. The grain also plays a factor in micro vibration absorbtion and or lack of it.

There is a balance between a tight grain versus a looser grain, in reagrds to absorbing micro vibration.


Axles / wheels.

I can tell you, that different axles, different axle shapes, and the plastic thickness / thinnness also play a role in weather the virbation goes out or down along the axle into the wood.

Some of the wheels, they are softer than the others, well the softer ones peform better. due to a slight absorbtion of the micro vibration, over the harder wheels. Not to mention, they polish up a little easier.


I'm running out of interest typing right now.

But i have more Id like to mention. nylon bushings, different types of bushings, copper, brass. ect.

I'll mention, tho that, I played with wax and different waxes in the wheel bore and on axles. to absorb micro vibration. Which really only worked with oil.

With many people who are adult racing are using some type of wax. Which was really weird, because I am more of a tinker and do things on my own person.

And it was really wild, to come to using wax with the oil for a faster car. I was tinkering with it for reducing micro vibration. Then I get into oil and racing with it. And fidn out many others are doing it or some version of it.

So often weather on your own or in a group or copy catting. You often can end up in the same direction, even if you are or were working on a different aspect of it all together.


Thats the same with axle head, the back side, that every one angles or smashes it, to reduce contact with the wheel bore area.

I was tinkering with different cuts and angles and grooves in the back side of the axle head, to disperse the micro vibration easier and quicker. To gain a tad bit of speed.

I mention this, is this also, was why I played around with different cuts in the hub of the wheel, bore area. which led to a tool made for the team sporty crew a few years ago.


Then I also played around with silicone, glues and ect, into the axle whole, different cuts on the end of the axle, thats inside the wood. To play with disperstion of the micro vibration.


I would use a jig that I rigged up to spin the wheels and use a dental pick to remove material from the middle of the wheel bore and all sorts of different things I was tinkering with. That idea came from people selling the left hand and right handed #44 taps for threaded bores.

But I didn't want a threaded bore. I wanted a ringed bore, that did not cross over into the other groove. Because i played with those threaded bores and had mixed results and views on that process.

I could really go on for hours, yet, on many more things i tried or did.

In dec 1994/jan 1995. I got my sons first soap box derby car. and spent hours looking for polish. I bought plast-x, micro gloss, micro polish.

Decided to try it in pwd. Often back then few people used it or knew about it. by March of 1995. I had bought my first batch of micro-mesh for my sons soapbox derby shell.

Tne I used it on the pwd wheels. I thought, works on this, should work on that. Not a pwd vendor that I know of was selling or offering it, as well as the super fine plastic polish or sand paper for plastics. Only in the model field. And i tried that type to, it wrecked to soon and did not work well.

Before long, I seen pwd sites, offering the stuff. Not once Did I ever see on those sites. my name or credit. Then I came up with on drawings and paper, tool designs late 2005 / early 2006. It did not take long, that some of them must have inspired some tools. that were simuliar in nature.

So, FS and others, if you are still reading this long post. This is really why I deal mostly in pm or over the phone these days.

You would not believe the issue I had with my hard work of the bore prep process that I came up with. it was not long after. I had people wanting to sell or take my work and ect. Some e-bay yin yang was out there not long after my post, trying to sell it as a kit or some deal. what a mess that was.

It's never been about the money for me, its been about my name.

There's allot more stuff I have done, I could go on, Im sure I did not invent it or ect. But I can assure you, I have not seen it posted anywhere or talked about.

Since I am back working at a plastic mold injection place. I get to see different lubes and chemicals. I have already shared two, that may work in combo or ect to be a very good speed improvement.

I got some "wheels" that I mean could be adpapted for razor bearing wheels. that we run sometimes. I got a few and Im hoping to send off to a former member of team sporty to tinker with. If it works out, it could be a low cost option for open class type races or something.

So if you read all of this. Let me know. Cuz I might think hard about revealing more and ect.

Sporty
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6856
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: Micro Vibration & a little more.

Post by Stan Pope »

Cool stuff!
sporty wrote: ... Im sure I did not invent it or ect. But I can assure you, I have not seen it posted anywhere or talked about.
...
Yes, there is a lot of that happening! Much reinventing.

One of the beauties of PWD is the opportunity to "invent" ... to see a problem and work out a solution. The really fun part is that some of that (re)inventing can be done by 8 or 9 year olds!

PWD also offers many opportunities for "discovery" ... even for an 8 year old. "Guided discovery" is a great learning method, too. For instance, Dad knows "it" is there, and asks the right questions that lead Jr. to discover "it"! Maybe helping the Dads to learn the right questions is more important than helping them to learn the right answers! Do I do them a disservice by posting answers rather than questions? Gonna have to think on that one a bunch! :)
Stan
"If it's not for the boys, it's for the birds!"
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6856
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: Micro Vibration & a little more.

Post by Stan Pope »

Okay, I've mulled it over a bunch...

New Year's Resolution # 341: Give no answers ... just ask "guided discovery questions!" :) I wonder if I can make it to my birthday before breaking this one? :(
Stan
"If it's not for the boys, it's for the birds!"
User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2804
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: Micro Vibration & a little more.

Post by FatSebastian »

sporty wrote:So if you read all of this. Let me know. Cuz I might think hard about revealing more and ect.
:eager: I read every word with keen interest! (Should you reveal more, I might recommend avoiding your own peeve of discussing multiple subjects in the same topic; perhaps different types of woods, wax lubrication, low-cost speed wheels, etc., could all serve as separate topics, for example.)
sporty wrote:I have been a firm believer, that one of the losses of energy / speed in a pinewood derby car. Was micro Vibration.
Yes.
sporty wrote: A wooden track, this is much harder to due. You could super sand it. then seal it, ect. But a even coat of sealer or ect on it. Still very hard to make even and smooth. When looking as a micro based level.
Much of what you say about stiffer materials wanting to vibrate more makes sense intuitively. However, when it comes to track surfaces, I wonder to what degree it is possible to separate the effects of “micro-vibration” and other losses due to, say, rolling friction (microscopic compression and expansion of the contacting surfaces)? Varnishing a wooden track makes the rolling surface harder (and easier to clean), which in turn seems to reduce the rolling friction and improves times. Or, does one cause the other?
sporty wrote:So it's just not a whole lot practical.
DT is loaded with stuff that's not “a whole lot practical” — but is still fun to think about! ;)
sporty wrote: while I saw times drop a tad. which thats all I was looking for was any kind of drop in times.
What is/was the magnitude of the changes in times you were looking for? How much a change is deemed “significant”?
sporty wrote:This is really why I deal mostly in pm or over the phone these days. [...] It's never been about the money for me, its been about my name.
Stan has also seemed concerned about maintaining traceable credit for various recommendations (even when it may be already be somewhat common knowledge!?). Nonetheless, if financial compensation for one's discoveries is not a motivator, then publicly disclosing hard-won information at least makes it almost impossible for someone else to claim exclusive ownership /patent rights to a process, tool, etc., that might or might not have been discovered independently.

What motivates different people to publicly share information (or not) seems to be yet another topic unto itself. Some participation in PWD may be motivated by financial profit, some by personal glory or ego, and some perhaps by something else again. So far we still remain motivated by the fun of building and trying to understand why things work (or don’t). I can imagine that there are some aspects of that exploration which, once taken to a particular level, become no longer fun. Perhaps something else (potential for money, bragging rights, etc.) continues to fuel interest once it is no longer "fun"? :idk:
sporty wrote:I could really go on for hours, yet, on many more things i tried or did.
I think there is immense value in discussing what has been tried but failed to produce improvements. This could be yet another topic; so much of that type of guidance is missing. There are lots of examples on DT of folks getting burned out; some of this is just due to people being at it for years without end but I suspect a lot of burn-out is fueled by people going down exotic or expensive dead ends that others may have quietly explored already.
sporty wrote:Since I am back working at a plastic mold injection place. I get to see different lubes and chemicals.
Yes, it seems that many advances come from exposure to / experiences from different trades and technologies. Advances in lubrication (e.g., Krytox) serves to illustrate.
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6856
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: Micro Vibration & a little more.

Post by Stan Pope »

Stan Pope wrote:Okay, I've mulled it over a bunch...

New Year's Resolution # 341: Give no answers ... just ask "guided discovery questions!" :) I wonder if I can make it to my birthday before breaking this one? :(
FAIL! But, oh, so close! If I coulda held on just one more day. :(
Stan
"If it's not for the boys, it's for the birds!"
rpcarpe
Master Pine Head
Master Pine Head
Posts: 736
Joined: Wed Mar 17, 2010 11:58 am
Location: Huntsville, Alabama

Re: Micro Vibration & a little more.

Post by rpcarpe »

Sporty,
I too read the entire post and subsequent posts. You're right, the entire discussion would be better off in a Pro forum.
Interesting stuff though, reminds me of how I listen to the sound of a car. My ear can often pick out the faster cars.
My wife started a new support group... Widows of the Pinewood Derby.
User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3344
Joined: Sun Feb 13, 2005 1:00 am
Location: rockfalls, Illinois

Re: Micro Vibration & a little more.

Post by sporty »

rpcarpe wrote:Sporty,
I too read the entire post and subsequent posts. You're right, the entire discussion would be better off in a Pro forum.
Interesting stuff though, reminds me of how I listen to the sound of a car. My ear can often pick out the faster cars.

I posted here, out of FS request for me to share and post my info. versus in pm.

So I am kind of darned if I do and darned it I don't.
User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2804
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: Micro Vibration & a little more.

Post by FatSebastian »

rpcarpe wrote:You're right, the entire discussion would be better off in a Pro forum.
:scratching: I didn't see where Sporty wrote that. He said "very few reach this level, when keeping a cub scout and scout race in mind." (Conversely, if one reviews the "pro" boards, one can find lots of remedial questions that a scout might ask, like "How fast do these cars go in miles per hour?", which might be "better off" on Derby Talk.)

IMO topics like this one keep Derby Talk interesting and relevant to a broader audience that still leans more toward kids racing. Sporty is describing physical effects that are not exclusive to "pros" but affect scout racers as well. The Go-Ask-Grandpa "flex car" has gotten lots of attention on DT over the years, a design which wants to address the concerns about micro-vibration that Sporty raises here. True, not everyone may have an interest in suspension systems but (thankfully) lots of things are still discussed on Derby Talk that might apply only to upper-echelon racers.
sporty wrote:So I am kind of darned if I do and darned it I don't.
Not at all! :thanks: Sporty!
User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3344
Joined: Sun Feb 13, 2005 1:00 am
Location: rockfalls, Illinois

Re: Micro Vibration & a little more.

Post by sporty »

Thanks FS.


See since I was a adult racer in 2010. I have tried to keep that seperate. There is lots of stuff I could share in that area and have.

The one thing, where most can still relate to scouts, is so many packs have different rules.

stock wheel base, exstended wheel base, 3 wheel cars, oil is allowed, modified wheels are allowed.

Sporty
User avatar
FatSebastian
Pine Head Legend
Pine Head Legend
Posts: 2804
Joined: Wed Jun 17, 2009 2:49 pm
Location: Boogerton, PA

Re: Micro Vibration & a little more.

Post by FatSebastian »

FatSebastian wrote:
sporty wrote: while I saw times drop a tad. which thats all I was looking for was any kind of drop in times.
What is/was the magnitude of the changes in times you were looking for? How much a change is deemed “significant”?
Also, still curious about what how much of a change / drop in times is considered an improvement when attempting to address this effect. One or two microseconds? Averaged over how many runs? Etc.
User avatar
sporty
Pine Head Legend
Pine Head Legend
Posts: 3344
Joined: Sun Feb 13, 2005 1:00 am
Location: rockfalls, Illinois

Re: Micro Vibration & a little more.

Post by sporty »

I cant recall how many runs.


the average drop was small, but there was a drop.

.005 to .007
User avatar
geauxturbo
Pine Head
Pine Head
Posts: 61
Joined: Mon Oct 10, 2011 12:57 pm
Location: Blew Bayou, LA

Micro Vibration & a little more.

Post by geauxturbo »

From someone who has hit a washboard dirt road at speed in stiff suspensioned jeep, i can relate to the issue on a grand level. If you are running your tires at 6 psi you glide right over. At 30 psi your teeth get rattled out of your head. But, what it seems you need is to dampen in the vertical and stay stiff in the horizontal. I would think the best way to accomplish that is with a slotted axle cuts with rubber inserts above the axle, nothing below, and wood preventing rotation of toe in\out in the horizontal. For instance, my jeep has 18" of travel of the axles with shocks (dampeners) vertically but it doesnt budge rotating in the horizontal. If it did, death wobble galore. The jeep would turn without steering input if you affixed the axle to the frame with shocks instead of control arms.

Fastening the axle to the rubber and not the wood would be tough. Maybe pressed between two layers of rubber in the slot would work. Im nowhere near that level of building, but the topic got my wheels turning in my head.
User avatar
Duane
Master Pine Head
Master Pine Head
Posts: 151
Joined: Mon Feb 01, 2010 10:25 pm
Location: San Jose,CA

Re: Micro Vibration & a little more.

Post by Duane »

geauxturbo wrote: But, what it seems you need is to dampen in the vertical and stay stiff in the horizontal.
"Grandpa's" flex chassis cars were motivated by his desire to cut down on noisy clatter on rough wooden tracks. He reasoned that the energy from that noise must be getting subtracted from the car's forward energy. I built some similar flex chassis cars (without racing them) and found that they tended to throb like a slow tuning fork because the motions weren't damped out. Others have noted how good wheel alignment is impossible to maintain without a rigid chassis.

I then switched to putting a layer of thin mouse-pad material between the rigid chassis and top-mounted metal weights. The front wheels could move up and down easily as in a normal car, due to the normal small Moment of Inertia there. The rear wheels could ride up and down more quickly and easily than in a normal car, due to the decoupling of the metal weight from the wooden rear of the car. And those up and down motions got quickly damped out rather than continuing forever. Alignment of the 4 wheels stayed rigid. I thought this was pretty nifty and the car ran well for our first year attempt. But I can't say that any of my notions of this method are proved.
Post Reply