55 replies to this topic

[MSwiss]

For the non-Facebooker's here on Slotblog;

 

[MSwiss]

PS: I don't have any idea what the theory is on it, but it should be faster if your slot is filled with water.

[The Number of]

Will you test that theory and get back to us?

[Racer36]

Does Evinrude make slot car motors?

[Steve Deiters]

I seem to remember guide flags like that way back when. Like the mid-'60s.

[gotboostedvr6]

Aqua blade would be a good nickname

[Jim Lange]

I have to admit, I was reluctant to believe the new style Red Fox was faster till I tried it myself. I will not pooh-pooh this guide till I try them. Obviously there is speed to be had with the guide that most of us so called "backyard engineers" don't fully understand. Is it the geometry? Is it from reduced friction because of the hardness of the material or the geometry? Is it a combination of the two?

[Dominator]

Looks like the blade extends behind the post further than on traditional guides.

[MSwiss]

I have to admit, I was reluctant to believe the new style Red Fox was faster till I tried it myself. I will not pooh-pooh this guide till I try them. Obviously there is speed to be had with the guide that most of us so called "backyard engineers" don't fully understand. Is it the geometry? Is it from reduced friction because of the hardness of the material or the geometry? Is it a combination of the two?

My feelings exactly, Jim.
 
I almost prefaced my post #2 with "I don't quite understand the theory behind the Red Fox guide so I certainly (don't have any idea on the theory on the Argentine one)
 
Racers will just have to try them.
 
If they are faster, guys will buy a lot of them.
 
If they break at the post, I'll attempt to pin them.
 
Jim,
Speaking of pinning, I took credit for the 1, 2, 3 sweep in F1 at BP this weekend.
 
I've sold them to you and Dale, but not to Sam.
 
Can I assume it was one I did?
 
If not, I certainly don't want to take credit (but until I hear others are doing it, I will. LOL)

[miko]

My two cents. Excuse the crude drawing but i think that the airfoil shape may be less drag against the sides of the slot. The top shows the straight guide with possibly the whole side of the guide touching the slot. The airfoil shape has a smaller area that would touch the slot at any given time. The arrows point to the area that would be touching the slot. Again just my tow cents.

 

[MSwiss]

I've tried 86 or 87 ways to make a guide shoe faster, and reducing drag against the sides of the slot didn't work.
 
You can drill the flag to do that, and someone sold a flag with large, round, slight depressions in the sides of the blade, and they weren't anything special.

[Rob Voska]

and someone sold a flag with large, round, slight depressions in the sides of the blade,

 
Slick 7 made those. The relief filled up with gunk.

[Zippity]

Thin teflon strips added to the blade seem to work - but the blades need to be thinned a bit, otherwise they jam in the slot.

[MSwiss]

Slick 7 made those.  The relief filled up with gunk.

Rob,

Thanks for the heads-up.

They should work well on my upcoming 1/24 "Oscar" track cleaning car.

[tonyp]

I noticed the Red Fox guides on our tracks down here pick up a lot of crud on the blade about 1/4 from the front. Parmas never seemed to do this.

[MSwiss]

Tony,

Are you implying the Parma flag is lazy? LOL.

I've noticed that on one of my racer's RF guide, that's on his hardbody car.

Also, for suppose to being real hard, they seem to wear a fair amount.

[kvanpelt]

I wonder if the pink ones will be faster, too!

[Jim Lange]

Mike, as you know, I stock them and I sold some to the Cervantes and Earl McCutchen. Not sure where Sam got his. Pretty sure no one is pinning them other than you. Just put one on our Enduro car. (Living on the edge, LOL.)

[A. J. Hoyt]

Not sure about the validity of the physics on this one. The widest point is in front of the post (pivot) which would steer the guide to the other side, causing it to bump from side to side on the straight sections when it seems obvious it would be preferable to spend the least amount of time in contact with the slot vertical walls (less friction drag running right down the middle, not contacting either side excessively). It might not be a time duration issue but one of friction generated by the magnitude of the side (normal) force. If it actually helps to minimize that time (or force) of contact, then that would be faster.

 

I can't even begin to speculate on what is happening in the corners. I have done computer simulations of slot contact using Adams high-end Multi-Body Dynamics software (it's what I have been doing for all of my employers since becoming an Applications Engineer for the company, now MSC, 20 years ago).

 

These simulations consistently show that the guide initially hits the slot wall HARD in the corners, then bounce to the inside wall, then less hard to the outside wall until about 90 degrees in where it stops bouncing and lays against the outside wall of the slot so it remains in contact for the second half of a typical 180 degree corner (flat or banked).

 

Knowing this has not caused me to change my chassis designs nor my driving style so it's not done me any good. I've said it before; the more I try to apply real engineering to slot cars, the less I know about what makes them work. It humbles me every time I try. I offer these observations because it might give others some ideas... 

 

What is important to know is that the friction is independent of the area of contact area, a fact I learned in high school physics (thanks, Mr. Williams, a personality very reminiscent of Mike Swiss - I'll just bet Nelson will agree!) but many degree holding mechanical engineers don't know this when quizzed on it. They go to the intuitive answer - more contact area creates more friction and it is never true (unless there is adhesive or high coefficient of friction fluid present). The physics math couldn't be more clear and Mr. Williams demonstrated this convincingly.

 

In the mean time, I certainly applaud the efforts to try something new. The simulation models respond to the shape of the contact so I can try this "aero wing chord" shape in Adams and see what it actually does - in theory, of course, as there are just so many variables in the modeling. I am working with Adams every day and it could be a nice evening project.

 

Keep it in the slot (never more profoundly and appropriately expressed),

 

AJ

[Racer36]

This sounds like a problem for Prof. Irwin Corey!

[JohnnySlotcar]

Perhaps they were designed for the Falkland Islands campaign!

[gc4895]

Wow, cool. I'm going to take a mill bastard to my Red Fox guides and hone them into shape!

[MSwiss]

What is important to know is that the friction is independent of the area of contact area, a fact I learned in high school physics (thanks, Mr. Williams, a personality very reminiscent of Mike Swiss - I'll just bet Nelson will agree!) but many degree holding mechanical engineers don't know this when quizzed on it. They go to the intuitive answer - more contact area creates more friction and it is never true (unless there is adhesive or high coefficient of friction fluid present). The physics math couldn't be more clear and Mr. Williams demonstrated this convincingly.

AJ,
 
Thanks for chiming in.
 
Mr. Williams sounds like he was super-charming.
 
When I posed the question of the theory of the design to the maker, he confirmed, "less friction."
 
I guess we'll see.
 
Speaking of new guide shoes, I wonder what the story is on the below. LOL.
 

[Eddie Fleming]

So, Mike, have you tried these and are you going to sell them?

[MSwiss]

I just saw the ones in the first post, yesterday, on Facebook.