FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: PSweeney on July 23, 2014, 03:01:17 PM
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I'm using a bellcrank set up to keep the steering link tight to the rails and proper ackerman. The set up I have at the minute is basically a 1/4 plate bellcrank pivoting on a 7/16 bolt shank. Now this would be fine for a soapbox but I kind of feel this needs to be better engineered. What set ups are you guys running, do you have bearings ? what material ? any alternatives to using plate ?
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check out this cars set up at 1.05
http://www.youtube.com/watch?v=-NP8UeWDUfM
correct me if I'm wrong but the drag links being connected to the same point, won't give correct ackerman settings ? ie both wheels will turn the same amount, whereas a dogbone end with two different arcs should turn the outer wheel to a greater degree
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Single ty rod to both steering arms and 1 short rod to 1 spindle arm
Make some aluminum bisqets to sandwich the bellcrank at the pivot with some thin teflon between the BC and alu bisqets. tighten bolt for slight drag.
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Phil, do you have front suspension? If so the set up that Bruce suggested is mandatory. It will also give better steering geometry with a rigid front end as the arcs described by the steering arms and the bellcrank are divergent which has a tendency to induce some toe variation as you increase steering angle, messing up the ackerman effect by overly accentuating it.
As shown in the video there will be toe variation even with the wheels straight ahead as the suspension articulates. With true ackerman geometry the inner wheel should turn at a greater angle so that it can follower a tighter arc than the outer as it is closer to the center of the turn that you are trying to make although this really only helps when navigating the pits unless you get really out of shape on your runs.
Roo
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Like this
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thanks for the response guys. Below is a simple sketch of my set up, excuse the crude drawing.
The car has no suspension. The tie rods are equal length and the pivot is mounted in the centre of the chassis.
(http://imagehosting.rodsnsods.co.uk/23253d2dc7cbb517.jpg)
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I know why I used Ackerman on my race karts but why on a dragster??
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I know why I used Ackerman on my race karts but why on a dragster??
why not ? they're simple cars but why not build in good geometry. I've lost a whole season chasing handling problems before with a car so with this one I want to ensure it's built right.
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Tire companys hate it
Drag cars go straight so anything above soap box derby steering (centerpivot and a rope) will work.