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Post by Professor Moriarty on Oct 8, 2017 9:34:34 GMT -5
Never tested with a good drill job.
If Mr. D ever ran for office, I think his campaign slogan would be “No, we can’t!”
A few posts back we were all talking about 1.75” wide tungsten pieces...
Years ago people discounted aero almost entirely on these cars and went for a conservative COM...
The envelope keeps getting pushed... and the direction it is getting pushed is the back edges.
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Tungsten
Oct 8, 2017 10:49:25 GMT -5
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Post by Chuy on Oct 8, 2017 10:49:25 GMT -5
Mr. D, I'm not saying that cars don't behave that way but I'm not understanding why they would. From a physics viewpoint a 4 oz. 1.75 diameter ring of tungsten would act the same way as a 4oz. BB right in the middle.
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Post by Professor Moriarty on Oct 8, 2017 14:31:45 GMT -5
I only somewhat see Mr. D’s point...
It was first postulated by BSB that with the further the weight is from the centerline of the car...
If the car got a wiggle then it would be amplified...
I think of it more like rocking on the rear wheels than wiggling.
However... we are talking about a 3 wheel car that wants to have the weight balanced between the two wheels...
So... due to the geometry of the triangle weight has to be shifted to the right side to achieve this anyway...
I feel like there must be a way that the COM could average things out...
Besides that... you can get more weight higher on the Hill with balanced rears using weight in the right wheel void!
Additionally... by putting the weight in the wheel void(s) it sets up all sorts of new aero possibilities that could shave time...
I just feel as if there has been very little testing done... and always with the same dogmatic thinking in the tests...
Building a standard car and tossing the side weights on may not be the answer... it probably involves building a car around the pros and cons of the weights.
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Post by Bracket Also on Oct 8, 2017 15:48:52 GMT -5
Never tested with a good drill job. If Mr. D ever ran for office, I think his campaign slogan would be “No, we can’t!” A few posts back we were all talking about 1.75” wide tungsten pieces... Years ago people discounted aero almost entirely on these cars and went for a conservative COM... The envelope keeps getting pushed... and the direction it is getting pushed is the back edges. Never tested with a good drill job? Oh please! Just because everyone else is catching on that a good drill is faster, it's not news to the guys that already knew! I'm only pessimistic about things that I already tried and found not to work. 1.75" wide tungsten weights hold promise, wheel cavity weights as we know them currently do not.
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Post by Professor Moriarty on Oct 8, 2017 15:51:14 GMT -5
Ha!
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Post by Professor Moriarty on Oct 8, 2017 15:53:29 GMT -5
Telling you... it is impossible to equal the precision of the clear drill jig.
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Post by Professor Moriarty on Oct 8, 2017 15:56:08 GMT -5
I have heard the same tune about the side weights from Hurricane And he uses the fubar DD drill jig...
Not a Bridgeport or a 4axis CNC can equal the precision...
Not a printed part... nothing can get it done like the clear jig.
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Post by Bracket Also on Oct 8, 2017 15:58:07 GMT -5
Mr. D, I'm not saying that cars don't behave that way but I'm not understanding why they would. From a physics viewpoint a 4 oz. 1.75 diameter ring of tungsten would act the same way as a 4oz. BB right in the middle. All I can say is try it and see for yourself?
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Tungsten
Oct 8, 2017 16:06:50 GMT -5
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Post by Chuy on Oct 8, 2017 16:06:50 GMT -5
Mr. D, do you have any video tape of these cars? Any observations or help would be appreciated
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Post by Bracket Also on Oct 8, 2017 16:14:21 GMT -5
I have heard the same tune about the side weights from Hurricane And he uses the fubar DD drill jig... Not a Bridgeport or a 4axis CNC can equal the precision...Not a printed part... nothing can get it done like the clear jig. Are you working without a fume hood AGAIN? You're definitely clouded if you believe that. A good drill is a good drill no matter how it came to be in existence. OK then, use your clear jig and your cavity weights and beat Hurricrane?
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Post by Bracket Also on Oct 8, 2017 16:40:17 GMT -5
Mr. D, do you have any video tape of these cars? Any observations or help would be appreciated None here, might be able to find some in the league footage but you'd have to go back a couple years, they were abandoned a while ago. Long story short, on a car without wheel weights, sometimes a fast car will move around a little in the rear. I say it's a product of an aggressive COM combined with zero toe in the rears, whatever it is, it's fast. It's referred to as a "sashay", not a wobble. If a car has the wobbles, it'll pull the front wheel off the rail where a sashay leaves the front wheel on the rail. Look at Craven's BASX from Friday night if you want to see a wobble. That poor thing was loose all over. If you watch a car that wobbles, you can often see that it's trying to rotate, yaw, about it's COM. It's skidding like it's on ice. With the wheel cavity weights on, it might hold the front wheel on the rail but the rear moves sideways enough that you can hear a ringing sound when the rear wheel makes contact with the rail and that kills the speed. Which is what BSB was talking about when he said it amplifies the wobble.
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Post by Professor Moriarty on Oct 8, 2017 16:50:48 GMT -5
I have heard the same tune about the side weights from Hurricane And he uses the fubar DD drill jig... Not a Bridgeport or a 4axis CNC can equal the precision...Not a printed part... nothing can get it done like the clear jig. Are you working without a fume hood AGAIN? You're definitely clouded if you believe that. A good drill is a good drill no matter how it came to be in existence. OK then, use your clear jig and your cavity weights and beat Hurricrane? I may beat him over the head with a sack of them. Lol! That is just the thing... it is like the chicken and the egg when it comes to a perfect drill... I wish that I could say more but I am sworn to secrecy on it... but to get a perfect drill job any other way is like a blind squirrel finding a nut. On a long enough of a timeline it can probably happen.
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Post by Professor Moriarty on Oct 8, 2017 17:58:20 GMT -5
Ok... you are probably saying to yourself:
“Joe, I have tested my drill jobs using the LightninBoy method and I know they are dead on!”
To which I would answer: the LB test is not the final word on testing for a good drill.
And I will say nothing more on the topic.
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Post by Professor Moriarty on Oct 8, 2017 18:26:54 GMT -5
Mr. D, do you have any video tape of these cars? Any observations or help would be appreciated None here, might be able to find some in the league footage but you'd have to go back a couple years, they were abandoned a while ago. Long story short, on a car without wheel weights, sometimes a fast car will move around a little in the rear. I say it's a product of an aggressive COM combined with zero toe in the rears, whatever it is, it's fast. It's referred to as a "sashay", not a wobble. If a car has the wobbles, it'll pull the front wheel off the rail where a sashay leaves the front wheel on the rail. Look at Craven's BASX from Friday night if you want to see a wobble. That poor thing was loose all over. If you watch a car that wobbles, you can often see that it's trying to rotate, yaw, about it's COM. It's skidding like it's on ice. With the wheel cavity weights on, it might hold the front wheel on the rail but the rear moves sideways enough that you can hear a ringing sound when the rear wheel makes contact with the rail and that kills the speed. Which is what BSB was talking about when he said it amplifies the wobble. Ok... first off... I love this new term. Sashay Chuy, I have done a little research on the subject using analogous topics and I can see how centralizing the weight best as possible is a good approach. However, Given the other restrictions to the puzzle...other considerations (geometry, real estate, aero etc.) If fellas were skidding their rears into the rail then it sounds like a bad drill to me.
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Tungsten
Oct 8, 2017 21:00:38 GMT -5
via mobile
Post by Chuy on Oct 8, 2017 21:00:38 GMT -5
So when the weight is moved out towards the wheels, the moment of inertia in the z (vertical axis) increases. You would expect this to dampen "the wiggles" and slow them down.
Is it possible the car had "the wiggles" and the weights helped by slowing them down? The wiggles is nothing more than oscillating rotational motion about the center of mass.
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