Laserman wrote:Hi fellas,
What a great thread!
Love that Sporty Spoon design.
Especially the way that it puts the front axles at about the highest point on the car and then dips down low.
I started building a wind tunnel a while back but got side tracked with other projects. Hopefully I will be able to post photos of the finished product before the end of winter.
It has two high powered 4" fans that funnel into a wind straightener made from straws.
Using an anemometer I was coming up with wind speeds of about 12mph.
After reading thru this thread I am starting to wonder how analogous it would be for certain testing.
As stated earlier, in reality the car is actually cutting thru the still air, not air moving fast over the car standing still like in a wind tunnel.
Laminar air traveling just beyond the edge of the boundary layer will most likely skew the results pretty fiercely when such small details can make big differences on these delicate little timepieces.
I wonder if dunking the car into a bucket of water and filming it at high speed would offer more.
Sporty mentioned downforce in his design of the spoon.
This idea is fascinating to me.
Can you tell us more about it Sporty?
Thanks
Sure, I thought I had, I's sorry If I had not.
Early on, I realized, more weight placed farther in the back. , back when people said, nope that's to far, you get stability issues, need to much drift to keep it to the rail, and thus loosing some potential speed.
So I think I said this a few times, im trying to recall how I all worded it. I may end up saying the opposite of a previous post I did. Hope not. Sorry if I do. lol.
The nose being so low and then there in the front, that's the lowest point on the car, that front edge, unless you add wood underneath it, but the center guide rail and many doing the axles location as high up as they can, and still have a tiny amount of clearance under the rail.
well, this means, and what I seen back then, air don't go under the center guide rail / under the nose there.
So, this is also the area that has the most wind / air, what ever we want to call it. (im tired at the moment).
So, its at its lowest point, with the least amount of resistance of air. with that design.
Now Iy you seen a few variations of my spoon design. I have played with it a bit and sometimes, Im just not consistently repeating the same shape. but close to it.
So, any how. with that out of the way.
The higher up axle slots, how the angle is done up and over that and the slope back down just past the axle area under the wood. gives a bit of downforce there.
That little bit of downforce, allowed me/kids. to have a farther back weight balance point, well back then, people thought I was wrong and crazy.
But, now, I did not have to do as much drift as my other ways did, and the front end would not micro bounce as much, running rail rider, with just one wheel touching.
I was not able to wind tunnel my design, it was one of the results of what I seen with the wind tunnel.
So I was only able to see visually and track times and less drift changes.
There is a bit of a trick to it, To much back slope going down behind the axle height or not enough drop, it does not work as well.
I should add in, our pack required 4 wheels down, very tiny amount of cant. and tiny mount of toe allowed. This design, helped us huge in scouts with the rules, we had to work with.
In factors of adult racing. Its probably a tiny amount of help. but should and has proven to do something. I forget and I might not have kept track.
I had not ever, planned on really seeing this design, become so popular with people. and it has worked well for a few on here and the scouts in the area that used it.
I see allot of great cars, well built cars, by great builders. talented people. They just got it !
I and my kids worked hard for a very long time. And I worked very very hard for a few years for myself. nothing came quick or easy for me, allot of hard work and time.
I think the difference, is my view was share it, help others. racing for those who want to win or work at doing a better car. should be able to find the information and understand it well enough to try and use the information.
Back on track, I hope that gave you a good reply there, tried my best.
Sporty