Thanks Cheap..
@ RogerRider; Certainly simpler packaging than a Peaucellier link...
What happens if the gears get a stone in the mesh though?
Thanks Cheap..
@ RogerRider; Certainly simpler packaging than a Peaucellier link...
What happens if the gears get a stone in the mesh though?
trueOriginally Posted by Momus
maby shielding around the gears
but yea i meant in packaging sense
Attachment 57828
would have similar constraints as jacob's ladder wouldn't it? better for something that turns one way, so it is in tension, not compression?
Last edited by morerevsm3; 11-06-12 at 08:18 PM.
E36 M3 12.92 @ 108.64mph, N/A 3.0L
Panhard Rod, Watts link and others are all in tension and compression.
Or you could just piss off all the complication and weight entirely ..
Last edited by cheapracer; 11-06-12 at 08:45 PM.
Ah, the old sliding block. Never seen it used beyond the dedion on the mid engined Bugatti GP car, and Alfa GTA/GTAms...
Yup except it's a roller bearing of course.
Not sure why I haven't seen it before (not saying someone hasn't), seems so logical and simple but of course not always easy to execute, the GTA looks nightmarish.
Lister Jag also a famous one that used it as well as Lotus, well "a" Lotus that I know of anyway - but all bronze blocks not rollers .. I find that strange.
.
The under diff A arm (Lotus Cortina) trunnion upper arm on 105 Alfas and the sliding block in it's various fitments, including BRM GP cars, can all be said to have been of questionable benefit to unsuccesful.
The Jacobs ladder has a home in American dirt track racing more because of regulation, and tradition than performance benefit. Panhards, leaf springs, inclined arms, either upper or lower all have shortcomings, at least in racing.
All these and the diff mounted Watt's rocker to my mind have the same weakness; the roll centre is fixed and does not move with the sprung mass centre of gravity. It introduces a varying lever arm length for the roll stiffness and appears to create issues with the roll axis and front suspension and steering.
Regardless of the reason and almost universally, replacing these with a chassis mounted Watt's or WOB (or I suspect the more complicated and highly loaded Mumford link), seems to iron out handling problems at the rear and turn a car into a driveable machine.
The Jacob's ladder with suitably long links and mounted on the diff with the 'A' member anchored to the centre of the chassis to give a RC might work but would be cumbersome and still compromised compared to a straight line linkage.
Last edited by Momus; 11-06-12 at 11:28 PM.
Succesful 105 Alfas rather than faithful GTAM type builds, usually have a chassis rocker Watts for about half the trouble and a quarter the expense of the slide block.
Lister did very well actually but doesn't answer my question, why did they all use a troublesome high friction and high stiction bronze slide rather than any type of rolling device ....
Impact loadings flogging the bearing would be my guess?
Oh, and most of what you see is support structure - 105 alfas are very soft structurally once you get further back than the diff. You should see the reinforcing kit for the big endurance tanks.
So what are my options with this puppy? I'm happy enough with the front suspension, at least until i run at and see how it goes. I would like to ditch the panard at the rear though and was thinking Wob link. With bugger all chassis at the rear for mounting though it's looking like a major headfark? How about a chassis mounted Watts that sits under the tailshaft?
GT8
1UZ Celica
1.07 flat Wakefield Park
best bet surely would be to add more chassis.
The Panhard is fine thought I'd like it to be a bit straighter fore/aft so the diff moves up/down a bit straighter.So what are my options with this puppy? I'm happy enough with the front suspension, at least until i run at and see how it goes. I would like to ditch the panard at the rear though and was thinking Wob link. With bugger all chassis at the rear for mounting though it's looking like a major headfark? How about a chassis mounted Watts that sits under the tailshaft?
No need to put a lot of work into something that doesn't really need it.
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For sure, less is best and will get me on the track quickerI could move the chassis mounted end easy enough and extend it towards the rear. If i'm going to that effort should i move that mounting point lower as well to make the panard more parallel to the axle line? Any tips on where to try and place the RC ie how far to lower the chassis mount?
GT8
1UZ Celica
1.07 flat Wakefield Park
Just make the RC a little higher than the front and try to make the Panhard as parallel to the diff housing at ride height as possible.For sure, less is best and will get me on the track quicker
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Light fabricaton & welding services.
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PF's official Chemtrails Pilot.
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Ta Bill. Given some of the other touches on the car i'm surprised the rear end isn't a tad more thought out? Anyways, i'll measure stuff up and see what can be achieved.
GT8
1UZ Celica
1.07 flat Wakefield Park
i cant see how a single roller would work for vertical motion- it still would function as a sliding block
ie :
if the roller is constrained by the two vertical guides:
for the diff to move vertically up- the side of the roller touching the left side of the guide wants to roll anticlockwise, where as the right side guide is trying to roll the roller clockwise
leading to the outer face of the roller not moving and becoming a slider anyways
hmmm - or you coul leave a small clearancebetween left and right guides - so one face unloaded with the clearance allowed roller to roll...
Last edited by 9triton; 12-06-12 at 01:12 PM.
If you gave it the same amount of clearance as a sliding block, the unloaded side of the roller would be clear of the guide. Easy.
Justen, some warped part of me would love to see a 27 T bucket body on that!
lol - editing my post as you replied..
It does have a suggestion of that already eh, with that angled ally side panel
GT8
1UZ Celica
1.07 flat Wakefield Park
1/2mm is fine for me. I actually gave it zero then welded the braces in expecting pull, it did. I am waiting to see how much it "clangs" and may look to see what composite material rollers are available at a later stage. I have 2 pieces of sacrificial plate lightly welded on for easy replacement as well predicting it will be a high wear area.
Justen, give me the length, spread and distance apart of your trailing arms and I'll run it through my bind jig.
And I think the Panhard is fine.
Last edited by cheapracer; 12-06-12 at 01:57 PM.
i was thinking a skate board wheel would be nice as a roller just my thoughts
Shhh, Grown ups are talking.
Last edited by Gammaboy; 12-06-12 at 06:34 PM.
"Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."
I vaguely recall the GTA guys aiming for less - but see how you go. Incidentally, they mostly run polymer slider inserts set into the bronze block these days.
"Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."
That skewed and archaic Panhard isn't doing the car justice, and the lack of rear structure seems a bit unsafe.
My suggestion which I have used to good effect on similar low polar moment coil overs mounted forward Sports Cars and Sports Sedans:
Last edited by Momus; 12-06-12 at 08:54 PM.
As Gamma said old engineers view rolling element bearings in oscillation or roller skidding conditions with great suspicion.
The block could just be a lateral application of a working system the designer had succesfull experience with.
Last edited by Momus; 12-06-12 at 09:06 PM.
Re the use and goodness of the slide block. As Gamma said old engineers view rolling element bearings in oscillation or roller skidding conditions with great suspicion.
The block could quite easily be a lateral application of a working system the designer hasd succesfull experience with.
On a different application, an on-car single shear adjustable Watts the slide block guide executed in acetal plastic works ok but getting zero play and fretting, is very hard without going to a difficult gib/slide arrangement in all metal
Cheers Momus, that design has appeal. Still pretty simple and also help strengthen up the rear. I was happy to live with panhard based on Bill and Cheapies advice, but with a neat option to ditch it i think this is a better way to go. Plus i get to stamp some input in finishing this thing.
I'll post up pics as i go to make sure i'm getting it right.
GT8
1UZ Celica
1.07 flat Wakefield Park
Indeed that's why the sacrificial plates and the cheapest, most common bearing I could find, maybe an hour's work and $10 every few years.
Unless it clangs a lot, not fond of clangs.
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