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Post by roosclan on Apr 2, 2009 20:58:35 GMT -6
My Tiger's car had quite a bit of wobble in it at our Pack's test & tune night last week (old wood track). CoM is at 3/4", and the car was lowered with the Pro Body Jig. 2.5neg camber on rear, 2.5pos camber on FDW. When it wasn't kicking off the rail due to roughness, it had quite a bit of wobble, and we finally tuned it out. I rolled it down our test board when we got home and the drift comes out to 2" in 2'. My Bear's car is tuned to 2" at 2' and my Webelo is about 2" at 3'
Pack race in tomorrow, and District is Saturday. The races will be on a 42' Best Track that is only 4 years old and very smooth. Considering the vast improvement in tracks, is this much steer goiing to be too much and slow the car down?
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Sappington R
Head in the Pine
"The Sappster" 10oz
Posts: 210
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Post by Sappington R on Apr 2, 2009 21:50:03 GMT -6
Roosclan, are you guys running 1 gm wheels or full weight BSA?
regarding your camber- less is more on the rear- lately we have been trying to stay less than 1 degree. and try to keep your front less than 2.5. Key is in the square alignment. Run Pos. on FDW. Saw it at the BGO- it's the winning ticket, es'pecially on a 42' Best.
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psycaz
Addicted to Speed
Posts: 86
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Post by psycaz on Apr 3, 2009 7:48:01 GMT -6
It could be that the roughness of the track was causing your wiggle.
It might be a bit much for 42', but as others have said, every car is different.
Make sure to rub some grapthite on the inner edge of the DFW where it will ride the rail. It will further help with it sliding and not sticking. You should pick up a bit of time. You'll definitely hear the difference.
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Post by roosclan on Apr 3, 2009 10:17:20 GMT -6
Roosclan, are you guys running 1 gm wheels or full weight BSA? We have to run full weight BSA wheels. Sanding the tread is the only thing that we can do to them (can't even cone the hubs). Well, we already bent the axles, so we're stuck with the 2.5 degree bend. We are definitely running positive camber on the FDW. My concern is with the amount of steer. With a long track like ours, I'm afraid that the aggressive steer we have may slow it down too much at the end of the run. I'm pretty confident in our rear alignment. We tried the new technique that Stan Pope came up with, and we found some definite need for adjustment on one of them. It really made a difference. |
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Post by roosclan on Apr 3, 2009 10:34:05 GMT -6
It could be that the roughness of the track was causing your wiggle. It might be a bit much for 42', but as others have said, every car is different. That is my main concern. I know I don't want less than 2" in 4' when it comes to steer with our aggressive CoM. The problem is that I don't have a track right now to test on. All I have is my test board. We do that already. It sure does make a difference! |
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Post by roosclan on Apr 3, 2009 22:16:20 GMT -6
Well, the boys cleaned up tonight, but we definitely have some adjustments to make before District tomorrow afternoon.
I tried to get them all tuned to 2" at 4', although my Webelo's car was about 2" at 3'.
My Webelo's car had almost no wobble that I could tell. His best time was 3.065s.
My Bear's car had a slight wobble in it, but was the fastest. Best time of 3.043s.
My Tiger's car had a very pronounced wobble to it in the last 8' or so. Fastest time was 3.082s.
Results: 1st in each den, and 1st, 2nd, and 3rd overall. No one was even close. Racing each other, My Bear and Webelo were quite close, about .016s apart
I'll definitely be retuning the Tiger's car, and Bear's car. I think I'll shoot for the 2" at 3' for all three of them, burn the wheels in with more graphite and my dremel felt wheel and call it good.
I'll make a new topic with photos after the District race.
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