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Lonnie's Mustang V6, "Steal with Both Hands", Locost
https://locostusa.com/forums/viewtopic.php?f=35&t=5886		 Page 154 of 195
Author:  Miatav8,MstrASE,A&P,F [ June 6, 2021, 6:07 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
I didn't realize you edited your last post to add the specs.

Why are your numbers asymmetrical from side to side? The specs are what you try to build to.
I averaged your specs and manipulated the spindle joints in an attempt to replicate them all. If you want accurate results, measure perpendicular from the joint cls to the wms on the rotor X and the axle cl Y. I also did not include loaded tire compression.
Lonnies Approximation
Author:  Lonnie-S [ June 6, 2021, 9:57 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
@MV8

Thanks for doing the VSUP run. I looked at the main page. I've never actually run the software, so I'm not familiar with its features and outputs. Nothing looked horrid to me at first glance.

Of course, I tried to be as accurate as possible when building things. However, in a home shop, errors creep in as you go. For example. drilling a 1/2" hole through big piece of RHS, the runout of the drill press shows in the far side hole. I measured what was actually built and tacked in place using 1/2" rod in place to measure from/to.

The variations are actually pretty small, but the consequences of even 1/32" can be surprising. The chassis was built with care, but it's not perfectly symmetrical since it was done by hand and not with jigs and fixtures. The standard means of welding the brackets to the chassis (used in both Book & Haynes versions) are going to reflect those imperfect dimensions for something thus built.

In my more rational and pragmatic state of mind, I realize the car is just about always going to be loaded asymmetrically in real life anyway (with me as the 170 lb. lump in the driver's seat) and all these precise, symmetric assumptions will go right in the dumpster. So, it going to be a matter of tuning the suspension of the imperfect, built car that will really matter. I just want to avoid things that will make that task difficult or impossible.

Cheers,
Author:  Lonnie-S [ June 9, 2021, 2:36 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
So, my next sub-project is going to be the lower, front control arms. I've been putting the components I have in place and trying to visualize what would be the most realistic design for me to fabricate.

Here's the spindle with the ball joint, ball joint housing (gray/black) and the Chrysler screw-in ring(shiny silver) mounted.
Attachment:
DSC05731.JPG

A closer view, ball joint centered in housing.
Attachment:
DSC05732.JPG

I was surprised by the angle of the ball joint with horizontal. It turned to be 17 degrees.
Attachment:
DSC05737.JPG

The ring itself is fairly narrow at 1", which would make it a tricky target for welding a 1" diameter DOM tube too. It's 2.5" in OD, so needs a pretty big hole saw to cut a suitable hole in steel plate, but I can do that.
Attachment:
DSC05738.JPG


I like to use tape to get an idea of angles and lengths involved.
Attachment:
DSC05733.JPG


I'm thinking a modified version of the Haynes Roadster design will be most realistic for me. It's larger/heavier than I'd like, but very simple and robust too. Here are some marked up shots of the Haynes design done in 3D. It isn't a design yet, just my first blush thinking. That's why I'm exposing it. I typically find that leads to improvements due to suggestions.
Attachment:
Design #1.jpg

Attachment:
Design #1 top view.jpg


Cheers,
Author:  Miatav8,MstrASE,A&P,F [ June 9, 2021, 7:48 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
I would not worry about a swaybar until you have one to fit. The uca makes more sense to load with a swaybar than the lca imho.

I'd do something like this for the lca with the plate smaller and narrower to align the edge with the center of the tubes, fitted to the bottom instead of splitting the tube. Tube ends are tapered 17 degrees. Coilover cross tube is fish-mouthed into the tubes and is 1/4 walled dom, further outboard for a better ratio and lower so the top mount can be lower also. I'd use the same size tube as the pivot shells (1-1/4?).

I'd also use 1/8 strip/plate versus 3/16.
Author:  Lonnie-S [ June 10, 2021, 10:26 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
@MV8

I like your idea of tying the tubes into the ring end plate. I'll be getting back to this tomorrow.

Cheers,
Author:  Lonnie-S [ June 29, 2021, 11:39 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
I don't have a specific design yet for the lower, front control arms, but I do have some ideas to try out. The cheapest way I know is to do paper, card for foamcore mockups augmented with various materials like string, tape, etc. I decide to use some scrap cardboard in this case. Mostly, I'm trying to figure out approximate sizes, locations and angles for the ideas I have.

I cut some cardboard to the 17 degree inclination the end plate carrying the screw-in ball joints will have, and they will hold the endplate mockup at the correct angle to center the ball joint in its housing at static ride height.
Attachment:
DSC05739.JPG

I created a centerline for the piece, used a compass to draw a suitable hole for the screw-in ring, and left a 3/8" margin around the outermost end of the ring to weld to all-around, and bent the card. Actually, I bent the card before I glued on the 17 degree pieces, but you likely figured that out on your own.
Attachment:
DSC05740.JPG

Mounted up the rough card mockup to the screw-in ring and ball joint assembly.
Attachment:
DSC05741.JPG

From those things I could use come fine elastic line as the "centerline" of the proposed 1" DOM tubes from each bracket/bushing to get approximate angles and look at how big the endplate must be to get sufficient length of weld on the DOM tubes.
Attachment:
DSC05742.JPG

Also, this will allow me to create a more refined mockup where the dimensions are much closer to what will be actually needed in practice. Mounting the lower end of the coilover shock units can be figured. This will greatly influence the overall size of the endplate itself.

Cheers,
Author:  Lonnie-S [ July 12, 2021, 11:28 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
I've been working on the lower control arm (LCA) design based on some ideas in play. Even though I've put a lot of time into it, I'm not happy with it. It's too complicated for my taste.

I was going to add a stiffener to the outside of the flat plate where it bends up @ 17 degrees, but I think I'm going to go with a more traditional design, so I haven't bothered yet as I may abandon it and start over.

However, I wanted to put it up for comment as I think I've been looking at it too long and fresh eyes almost always yield improvements. Maybe I'll get a nice surprise?

Cheers,
Attachment:
LCA-V1 #1.jpg

Attachment:
LCA-V1 #2.jpg

Attachment:
LCA-V1 #3.jpg

Attachment:
LCA-V1 #4.jpg
Author:  seven13bt [ July 12, 2021, 11:44 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
Suggest attaching the front and back tubes directly to the LBJ collar. An example from my Locost:
Author:  Miatav8,MstrASE,A&P,F [ July 13, 2021, 8:15 am ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
Also look at where the crossection is thinnest in the fore-aft view to see where the arm will flex and be notch-sensitive. Between the lbj cup and the coilover brkt and between the coilover brkt and the end of the tubes.
If you keep crossection uniform, the arm can flex along it's length when overloaded rather then bend much easier in a narrow section.
Author:  Lonnie-S [ July 13, 2021, 2:05 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
seven13bt wrote:
Suggest attaching the front and back tubes directly to the LBJ collar. An example from my Locost:


That was my first thought, Ron. However three things persuaded me not to:

1) My DOM is 1" as is my screw-in ball joint ring, so the fishmouthed DOM will come above the edge of the ring - no shoulder. So, for me, not a good welding target;

2) With my MIG skills, I'm almost certain to spoil the threads because of too much heat added with such a large, continuous weld bead;

3) With the plate approach, I can do a small series of say 3/8" welds alternating top and bottom, keeping the heat down while being confident the ring will be sufficiently welded in and not fail.

I just think the plate approach is better suited to my welding skill level.

Cheers,
Author:  Lonnie-S [ July 13, 2021, 2:07 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
@MV8
Thanks for that insight.

I'm going to leave it alone for a day, them reevaluate the design.

Cheers,
Author:  rx7locost [ July 13, 2021, 3:00 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
While the plate may be better for your welding skills, it is a rather poor design physics-wise. To resolve #1, you could crush the end of the tube a little to give you weld fillet room. #2 I have no input. #3, I don;t see how this would be any different from welding a couple of tubes.

Just sayin'.
Author:  Lonnie-S [ July 14, 2021, 1:16 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
rx7locost wrote:
. . . #3, I don;t see how this would be any different from welding a couple of tubes.

Just sayin'.


Small, symmetric beads added slowly will minimize distortion. All the welds beads would be simple fillet welds.

Cheers,
Author:  rx7locost [ July 14, 2021, 1:44 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
But, nothing says you can't weld like that with a tube.
Author:  niko [ July 14, 2021, 2:11 pm ]
Post subject:  Re: Lonnie's Mustang V6, "Steal with Both Hands", Locost
Your 3d model would be better with another piece of plate above the tubes.
In fact there is no need to have it lying top and bottom of the tube . They'll probably end up below flush with plenty of space for wide welds .
Square tube is also an option .
For the welding I've had good results with a piece of wood pressed firmly in the opening . Stinks like hell but should keep the threads clean .
Cheers
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