Thinning the front of a car

[Vitamin K]

Just build 2 cars, sand the front end different for each, and see how they do. My guess is you wont see much if any difference in times. Use the same wheels and axles for each.

I think using two different cars has the same problem as flipping a single car. Since nobody builds perfectly, you're still introducing uncontrolled differences between the two tests.

My guess is that the angle of the nose would have very, very minute differences. But if there are any, you'd want the test to be as tight as possible to try to find them.

 

[ngyoung]

I think the experiment proposed was to drill holes that were parallel to the ground, no canting. Use a 1/4" body with a sloped nose and run it both directions. Adding steer to the DFW would be the one variable that you would be hardest to get exactly the same, assuming you use any steer.

 

[Obsessedderbydad]

You're never going to have the perfect test. So, unless you're a die hard that is going to dwell over this, your going to have to make 4-6 cars and record the results and go by average.

 

[Vitamin K]

You're never going to have the perfect test. So, unless you're a die hard that is going to dwell over this, your going to have to make 4-6 cars and record the results and go by average.

You don't need a "perfect" test car, that's missing the point. You need a car that has nothing changed on it except the thing that you are testing.

Let's take three examples: A car that can be 'flipped over' to run in reverse, two 'identical' cars built with different shaped fronts, and a car with a front end that can be installed in a normal position, or rotated 180.

With the flipped car, whenever you flip it, you are running with the wheels completely inverted, and riding the opposite side of the rail. You are also inverting all of the axles. All of these things could possibly affect performance, in ADDITION to the changed shape of the front end.

With the "identical" cars, it is even worse, because you can find minor variances in almost everything in the car. Wheel trueness. Axle angle. Weight placement. Lubrication. Etc. Etc. Etc.

With the car with a reversible front end, you have the advantage that more things remain the same. The wheel placement stays the the same. The axle angles stay the same. The side of the guide that you run on stays the same. All possible sources of changed runtime eliminated. Are there flaws in the car? Of course there are! We are humans, after all! But the point is that the flaws will stay consistent from run to run.

 

[Obsessedderbydad]

that's why i said build 4-6 cars and take the average. Use the same axles and wheels on each car. That's the easiest way to test a theory.

 

[Rocket car]

I split the difference top and bottom then it is perfect! No lift , no down pressure. You guys are making my head hurt.

 

[ChrisF]

Build a car to take a modular nose. Make your different nose configurations out of balsa or whatever. Attach to the car, compensate for the differences in weight. Test to your heart's content.

 

[B_Regal Racing]

Rhinoplasty - I like the idea.

 

[letmrun]

Build a car to take a modular nose. Make your different nose configurations out of balsa or whatever. Attach to the car, compensate for the differences in weight. Test to your heart's content.

ChrisF is right. Build 1 car, preferably a long wheel base, with a blunt nose. I suggest a long wheel base to keep the added modular nose from dragging at the slope. Make a modular nose with a slope on one side and straight on the other. Attach the modular nose to the front either with double sided tape or make a small dowel to hold it, etc. Run it a few times with the slope on top, avg. the times, then turn the nose over and run it with the slope of the nose down, avg. the times. Lowest avg. wins. You are using the same car, with the same wheels, same DFW, and same weight. Only variable is the direction of the slant on the modular nose. Once your are done you can remove the modular nose and slope the nose of the actual car however you wish. Good luck and I would be interested in the results.

 

[BulldogRacing]

hypothesis, there will be more of a difference in the slight staging effects of the car then you'll see from the slight difference in the nose of the car.

 

[Guest]

...

 

[Vitamin K]

Build a car to take a modular nose. Make your different nose configurations out of balsa or whatever. Attach to the car, compensate for the differences in weight. Test to your heart's content.

ChrisF is right. Build 1 car, preferably a long wheel base, with a blunt nose. I suggest a long wheel base to keep the added modular nose from dragging at the slope. Make a modular nose with a slope on one side and straight on the other. Attach the modular nose to the front either with double sided tape or make a small dowel to hold it, etc. Run it a few times with the slope on top, avg. the times, then turn the nose over and run it with the slope of the nose down, avg. the times. Lowest avg. wins. You are using the same car, with the same wheels, same DFW, and same weight. Only variable is the direction of the slant on the modular nose. Once your are done you can remove the modular nose and slope the nose of the actual car however you wish. Good luck and I would be interested in the results.

I agree with this. And, just for the sake of argument, this is pretty much the very same proposal I made originally.

 

[ChrisF]

I agree with this. And, just for the sake of argument, this is pretty much the very same proposal I made originally.

Too late, I already patented it (btw modularity allows for more test possibilities than simple flipping/rotating).

I do agree that in this case you want to isolate what you want to test without introducing the confounders of differing (even minutely) builds.

 

[letmrun]

My apologies to Vitamin K. I saw the original post, thought of a solution, rifled quickly through the posts to see if it had already been mentioned, saw the post by ChrisF, but missed where Vitamin K had mentioned about a rotatable front end. I am sorry, no slight was intended. I'll just go sit in the corner now.

 

[Vitamin K]

My apologies to Vitamin K. I saw the original post, thought of a solution, rifled quickly through the posts to see if it had already been mentioned, saw the post by ChrisF, but missed where Vitamin K had mentioned about a rotatable front end. I am sorry, no slight was intended. I'll just go sit in the corner now.

It's all good, mate. /images/boards/smilies/biggrin.gif

 

[B_Regal Racing]

It's all good, mate. /images/boards/smilies/biggrin.gif

"How to Speak Australian."

 

[BulldogRacing]

tip top. bip bip.

 

[zeebzob]

I have never had a car flip ass over teakettle in the stop section.

I stand corrected.

 

[Kinser Racing]

I have never had a car flip ass over teakettle in the stop section.

I stand corrected.

That was not cool man!

 

[zeebzob]

I have never had a car flip ass over teakettle in the stop section.

I stand corrected.

That was not cool man!

In the end, it all worked out. Also, I want to be clear that it was just a weird fluke thing. In no way do I think the track had anything to do with it. The track was smooth and fast. The stop section was correctly aligned....its just one of those things.
The truth is, I was Karma's b*tch right then!