land-speed
[Top] [All Lists]

Re: [Land-speed] TOE IN

To: DougOdom <dlodom@charter.net>
Subject: Re: [Land-speed] TOE IN
From: drmayf <drmayf@mayfco.com>
Date: Tue, 10 Jul 2007 08:29:53 -0700
Doug, I suspect that the length of the steering arm at the wheel would 
have to be changed.  This is a very common issue with the SUnbeam Tiger 
sitting in my garage. The ackerman angles are truly farkled. As you 
turn, the inner wheel turn some but the outer wheel turns more! Makes 
for lots of oversteer. Thias all came about because Carroll Shelby was 
in a hurry to get the Tiger back to Lord Rootes for production design. 
Put the steering rack in the way wrong spot and then added angles tie 
rod ends to cure the problem. Result...ok in a dead straight line not 
worth a plugged nickle on a turn. Many things tried to fix. Only thing 
is a new front end design.

All, regards front end design for an in-line streamliner. On a four 
wheeled car in normal configuration, the front tires are separated by 
the track of the front tires. And as has been stated, if you turn, then 
the line drawn perpendicular to the wheel (or a line entending from the 
spindle straight out) strikes the line drawn through the rear axle 
(think of long extended axles). Then the outer wheel must turn  in a 
manner such that the line extended from the spindle meets the  same 
intersection point on the rear axle line as the inner wheel intersection 
line. SOunds complicated but really isn't.  Now I have not built or even 
participated in the building of a liner with inline steering wheels. But 
here is how I would do it. I would draw the line through the rear axle 
and put the car's centerline on it. Then measure up to the centerline of 
the rearmost steering wheel. Then scribe an arc down to the rear axle 
centerline. Do the same for the front steering wheel. If you do this, 
you will see that the front wheel turns less than the rear steering 
wheel. This would I believe be a correct ackerman.  Then I would fab up 
the steering arms to make this happen. I could very well be wrong in 
this however. It is my turn to be wrong this week...  Unfortunately this 
is really complicated by caster.  In order to work perectly the 
suspension would have to be straight up and down through the contact 
patch without any heeling over due to caster or king pin offset.

Or you could run a bike...

mayf


DougOdom wrote:

>John Burk wrote:
>
>  
>
>>Doug asked
>>
>> 
>>
>>    
>>
>>>How can you measure ackerman if you do not know the length of the steering
>>>   
>>>
>>>      
>>>
>>arms and the >distance they are apart?
>>
>>Doug , if the ackerman is correct the axis of each front wheel crosses the
>>axis of the rear wheels at the same point . If the left front is turned 1 deg
>>left and the wheel base is 10 ft the radius of that triangle is 573 ft . If
>>the front tread is 4 ft the right front triangle (10 x 577) is .0993 deg .
>>
>>John
>> 
>>
>>    
>>
>OK, Now if the ackerman is not correct after you measure it, what will 
>you change to make it correct?
>  Doug
>_______________________________________________
>drmayf@mayfco.com
>
>Land-speed mailing list
>
>http://autox.team.net/mailman/listinfo/land-speed
_______________________________________________

Land-speed mailing list

http://autox.team.net/mailman/listinfo/land-speed

<Prev in Thread] Current Thread [Next in Thread>