Landracing Forum Home
March 24, 2019, 06:54:12 PM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News:
BACK TO LANDRACING.COM HOMEPAGE
 
   Home   Help Search Calendar Login Register  


(Note: Donations are not tax deductible)







Live Audio Streaming and Archives of Past Events
Next Live Event: TBD
Pages: 1 2 [3]   Go Down
  Print  
Author Topic: Lakester rear suspension  (Read 30463 times)
0 Members and 1 Guest are viewing this topic.
Interested Observer
Sr. Member
****
Offline Offline

Posts: 373




Ignore
« Reply #30 on: February 02, 2017, 09:24:08 AM »

While OJ is correct to raise the consideration of  squat and lift, the description he gives of how to deal with it is not correct.  What he describes applies to an independent rear suspension system, while what is considered here is a solid axle on control arms, the control arms being the rear sub-frame and the suspension instant center being the sub-frame pivot point.  The relationship of the axle centerline and the pivot has nothing to do with the squatting characteristics if the axle is attached to the sub-frame.
Any time forward tractive effort is applied (at ground level), the reaction will be to raise the pivot point, and consequently the chassis.  The only way to mitigate this reaction is to lower the pivot point, giving zero lift when it is at ground level.  Likewise, any rear braking will induce squat to the chassis.
Logged
oj
Full Member
***
Offline Offline

Location: I'm Oj, living in the Shenandoah Valley of Virginia
Posts: 61





Ignore
« Reply #31 on: February 02, 2017, 04:37:45 PM »

I see the 'rear subframe' as nothing more than an extended 4 link.
Logged
oj
Full Member
***
Offline Offline

Location: I'm Oj, living in the Shenandoah Valley of Virginia
Posts: 61





Ignore
« Reply #32 on: February 16, 2017, 09:00:38 AM »

After thinking things thru I see it is more complicated than I thought.  It is quite a bit different from a 4 link, the problem as I see it the 2 lower attachment points to the chassis are more a hinge.  Hmm.
Logged
Peter Jack
Hero Member
*****
Offline Offline

Age: 75
Location: Calgary, Alberta
Posts: 3576





Ignore
« Reply #33 on: February 16, 2017, 09:46:07 AM »

The thing it's closest to is ladder bars with the engine mounted on the bars. Depending on where the engine is mounted in relation to the pivot point more or less weight will fall in the unsprung category. My feeling is it's way too much work for the dubious results that may occur.

Pete
Logged
SPARKY
Global Moderator
Hero Member
***
Offline Offline

Age: 76
Location: Phoenix
Posts: 6630




« Reply #34 on: February 16, 2017, 11:45:27 AM »

 cheers
Logged

Miss LIBERTY,  changing TKI  to noise, dust and RUST!!!

The # 1 issue is: TO KEEP THE REPUBLIC      
   Center for Self Governance            tncsg.org     mrspowell.org

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller
Elmo Rodge
Hero Member
*****
Offline Offline

Location: Smack dab in the middle of Utah
Posts: 1512





Ignore
« Reply #35 on: February 17, 2017, 12:33:26 AM »

On my Lakester, it is solid in the rear. My thinking is; No engineering is better than bad engineering.  wink Wayno
Logged
Jack Gifford
Hero Member
*****
Offline Offline

Age: 78
Location: Phelps, NY
Posts: 1217





Ignore
« Reply #36 on: February 17, 2017, 01:06:08 AM »

... The thing it's closest to is ladder bars with the engine mounted on the bars. Depending on where the engine is mounted in relation to the pivot point more or less weight will fall in the unsprung category. My feeling is it's way too much work for the dubious results that may occur...
I agree with all of that. Except that in my case the "way too much work" is offset somewhat by the fact that the nicely designed torsion bar suspension is already in place for the rear wheels. So the only "work" I'd be left with is design & fabrication of the subframe and its frame-anchored pivot. [While avoiding the "work" of mounting the rear axle rigidly]

With an A-shaped subframe, it's closest to ladder bars with their front pivots moved together. This would preserve the non-binding independent travel of each rear wheel.

As for "dubious results", I've seen a number of examples of satisfied landspeed racers using some form of suspended rear subframe.

Thanks for all the comments.
« Last Edit: February 17, 2017, 01:08:20 AM by Jack Gifford » Logged

M/T Pontiac hemi guru
Jack Gifford
Hero Member
*****
Offline Offline

Age: 78
Location: Phelps, NY
Posts: 1217





Ignore
« Reply #37 on: September 25, 2017, 11:06:22 PM »

Although I'm usually not a fan of swing axles, it looks like I should at  least consider them. It has the attraction of true independent suspension, and limited travel would keep the tires reasonably "upright". And by doing quite a bit of the machining myself it might even be inexpensive to convert my 8" Ford center section- depending on what "works" for axle U-joints.
Logged

M/T Pontiac hemi guru
manta22
Hero Member
*****
Offline Offline

Age: 80
Location: Tucson, AZ
Posts: 3316


What, me worry?




Ignore
« Reply #38 on: September 25, 2017, 11:48:39 PM »

Jack;

Have a look at a Dedion rear suspension, it should be better than a swing axle (think old VWs).

https://en.wikipedia.org/wiki/De_Dion_tube

Regards, Neil  Tucson, AZ
Logged

Regards, Neil  Tucson, AZ
ntsqd
New folks

Offline Offline

Location: Granola State
Posts: 5




Ignore
« Reply #39 on: February 17, 2019, 04:38:53 PM »

I was just about to suggest the same, the deDion axle design. Seems to me that a deDion axle might be a better choice IF the 1/2 shafts are set such that they're level at speed (CVJ's running with no angle) to keep parasitic losses to the bare minimum. I would place the deDion tube behind the1/2 shafts so that I could use the pin/bearing in a slot (that is attached to the diff housing) method for lateral location. This would allow servicing the diff w/o having to disassemble the whole rear suspension too.

I did read 8" Ford, right? Just a slightly smaller & lighter 9" in design. A friend built a 9" housing narrower than Currie said it could be done. He literally cut the housing so that normal semi-float bearing ends fit up against the diff adjusters with *just* enough clearance should the diff be really offset in the drop-out. Application was different, but the approach worked then and still is working in that IFS 4WD truck 20-odd years later. I think it was Summers Bros who made the flanged axle shafts for him.

I would use the aero version of this CVJ boot: https://www.pegasusautoracing.com/productselection.asp?Product=1472 or this aero boot: https://www.pegasusautoracing.com/productdetails.asp?RecID=5549 depending on the CVJ size chosen. Could even attach a simple aero fairing to the deDion tube to enclose the outboard CVJ's and and 1/2 shafts.
Logged

Cross-threaded is tighter than Lock-tite.
Jack Gifford
Hero Member
*****
Offline Offline

Age: 78
Location: Phelps, NY
Posts: 1217





Ignore
« Reply #40 on: February 17, 2019, 11:38:25 PM »

Thanks for the reminder of the DeDion option.
Logged

M/T Pontiac hemi guru
Pages: 1 2 [3]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!


Google visited last this page January 30, 2019, 12:35:08 PM