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Learning how to build Lotus Seven replicas...together!
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PostPosted: Mon Apr 16, 2012 12:44 pm 
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Here are some additional detail photos.

I'll start with a view of what's behind the rear fascia of the front body work. You can see that there is a lot of detail and important duct work even in this simple piece. It does give an appreciation of how complex these race cars are. Everything here had to be designed, molds made, pieces created or assembled from smaller pieces and then the whole of it assembled and tested. Even this relatively simple component is pretty complicated. I wonder how many engineering and build hours went into it?

Attachment:
File comment: Rear view of front body work.
Evora-GT-Behind-Front-Facia.jpg
Evora-GT-Behind-Front-Facia.jpg [ 362.82 KiB | Viewed 758 times ]


Here is a view of that same body work mounted. The wheel wells and fenders are separate pieces too. I wasn't able to get a good shot with everything off and the bare chassis in view. It was a matter of timing. they were swarming all over it trying to get it ready for the race and lots of parts or tool boxes blocked the way.
Attachment:
File comment: Front body work mounted.
Evora-GT-Front-Bay.jpg
Evora-GT-Front-Bay.jpg [ 144.5 KiB | Viewed 758 times ]


Here's the top piece, which also is pretty complicated. I did see the back too and like the front fascia, it is more complicated than you'd think. Notice the three flush mounted body work fasteners. Dzus fasteners are throwbacks in this intense aero-age and these are what you see on all the professional cars.

Attachment:
File comment: Top, front body work.
Evora-GT-Radiator-Vents.jpg
Evora-GT-Radiator-Vents.jpg [ 184.72 KiB | Viewed 758 times ]


I hope you enjoyed these.

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Tue Apr 17, 2012 4:15 pm 
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Geez Lonnie, I didn't realize you were such an old fart! Thought you were still young like me. :P

So you were born in Long Beach? Me too - St. Mary's in downtown back in 1954. Where did you go to high school? I was at Wilson.

Looking forward to seeing more photos of the build. Take it easy when stuff starts hurting, means it time to go in and have a rest.


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PostPosted: Tue Apr 17, 2012 4:24 pm 
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Locost_Johnh wrote:
Geez Lonnie, I didn't realize you were such an old fart! Thought you were still young like me. :P

So you were born in Long Beach? Me too - St. Mary's in downtown back in 1954. Where did you go to high school? I was at Wilson.

Looking forward to seeing more photos of the build. Take it easy when stuff starts hurting, means it time to go in and have a Pitcher of Margaritas delivered by a buxom young waitress in a low-cut top.


There, fixed that for ya, John!

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JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


Last edited by GonzoRacer on Wed Apr 18, 2012 6:46 am, edited 1 time in total.

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PostPosted: Tue Apr 17, 2012 11:03 pm 
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Locost_Johnh wrote:
Geez Lonnie, I didn't realize you were such an old fart! Thought you were still young like me. :P

So you were born in Long Beach? Me too - St. Mary's in downtown back in 1954. Where did you go to high school? I was at Wilson.

Looking forward to seeing more photos of the build. Take it easy when stuff starts hurting, means it time to go in and have a rest.


Yep, sorry John, I'm now officially a geezer. But, I do have health care through Medicare now, so if I get hit by a car while riding my bicycle they'll find me a nice warm corner of the ER to bleed out in. I think you need the full-up commercial insurance to get actual treatment now. :ack:

Yes, I was born at old St.Mary's too. I loved growing up in Long Beach. We were happy kids in my neighborhood and never could get bored because there was so much to do there. I was so brown from being at the beach, lots of people though I was a Mexican kid. We moved to Northern California when I was in grade school and I received most of my education there and spent the majority of my professional life there as well.

Hello to Carolyn and the kids from us.

Best,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Tue Apr 17, 2012 11:20 pm 
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GonzoRacer wrote:
Locost_Johnh wrote:
Geez Lonnie, I didn't realize you were such an old fart! Thought you were still young like me. :P

So you were born in Long Beach? Me too - St. Mary's in downtown back in 1954. Where did you go to high school? I was at Wilson.

Looking forward to seeing more photos of the build. Take it easy when stuff starts hurting, means it time to go in and have a Pitcher of Margaritas delivered by a very buxom young waitress in a very low-cut topthat actually falls off when she leans over to serve you.


There, fixed that for ya, John!


Thanks for the spirit of your post, JD. I fixed your fix (red text) and also finished the story for you too. John's a very good family man (and a hell of a nice fellow), so he doesn't think like you and I do. :wink:

Cheers,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Wed Apr 18, 2012 4:07 pm 
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Fixed them up right, that's for sure! Time for a cold shower - forget the nap. :cheers:


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PostPosted: Wed Apr 18, 2012 9:54 pm 
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Locost_Johnh wrote:
Fixed them up right, that's for sure! Time for a cold shower - forget the nap. :cheers:


10-4, John.

I'm back working on the car every day now. I should have something worth showing pretty soon.

Cheers,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Sun Apr 22, 2012 4:24 pm 
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This weeks objective was to get the new front frame completed, which means a lot more in my case then just cutting some steel as described in a book and welding it together. My car is a custom version of the Haynes Roadster. When I did the first version I was thinking I'd preserve all the essential angle and distances of the (Haynes) book design for the front frame. That was when I thought I might use the classic Locost suspension design. Truth be told, I never liked those simple U-brackets welded onto the 16 gauge members. It never really seemed adequate to me in terms of strength and rigidity even though it obviously does work.

In preserving the original book configuration using my larger chassis materials, I ended up with a compromise in the way elements fit together. The edge to edge match-up of the pieces was not as good as I wanted. I felt I could do better, but would have to give up the precise duplication of the book pattern. That's what I decided to do recently because I have decided not to use the book U-brackets.

Attachment:
File comment: New drawing for version 2 front frame.
New-FF-Drawing.jpg
New-FF-Drawing.jpg [ 113.09 KiB | Viewed 569 times ]


I originally designed the chassis in one software product, but switched to a new one after completing it. That meant starting over with the front frame design rather than modifying the old one and mastering the new software at the same time. The front frame is a very tricky part. It's very clever in a number of ways, but way too complicated, I think. However, I'm too far into the project to start all over again with something completely new. I needed to improve what was there in terms of the fit for my chosen materials. All of this lead to a lot of delays and rework. However, It's done now and I think worth the effort.

Attachment:
File comment: New Front Frame.
Front-Frame-Assembly2.jpg
Front-Frame-Assembly2.jpg [ 102.91 KiB | Viewed 569 times ]


Attachment:
File comment: Three quarter view. Lots of compound angles to fit.
Front-Frame-Assembly.jpg
Front-Frame-Assembly.jpg [ 77.38 KiB | Viewed 569 times ]


I was able to salvage the original jig I built way back in the wooden mock-up phase. It was tricky to build some blocks that positioned it precisely. I made trial pieces in wood first using my compound miter saw, so I would not waste steel. That revealed that I needed to shim up the top most piece and a little paper and blue painter's tape provided the final adjustment needed on the jig.

Attachment:
File comment: Basic pieces in reworked jig.
FF-Basic-Pieces.jpg
FF-Basic-Pieces.jpg [ 114.89 KiB | Viewed 569 times ]


Attachment:
File comment: Working out a precise fit and final jig adjustments using wood mock-ups
FF-Tricky-Bits.jpg
FF-Tricky-Bits.jpg [ 85.61 KiB | Viewed 569 times ]


Attachment:
File comment: Excellent final fit-up in steel.
FF-Rework-Objective.jpg
FF-Rework-Objective.jpg [ 72.17 KiB | Viewed 569 times ]


That extra step gave me an excellent fit-up in the steel parts. The pieces at bottom actually fit to FF1 very well. The radiused edge of the bottom FF1 member, and this camera angle, make it look like a larger gap than it really is in real life. There is a fraction of a MM overhang on the backside due to the compound angles and keeping the front edge as flush to FF1 as possible. I just built up a little ledge of weld material to make sure it is well supported.

The cross braces are 3/4”, 16 gauge tube reinforce the area of the front suspension pickups. They're just tacked in place at the moment. I want to do a little more practice welding of thin, round tubes to thicker RHS before doing the final welds.

These kinds of things are an additional factor in my slow progress. First I have to design it, then I have to build it and often I need to master some practical fabrication process before I can complete it 100%. However, I'm not complaining. I've set this task for myself and am really enjoying the challenge of it all. I've also set a high standard for accuracy too, which I'm doing pretty well with. This piece is also my first fit-up of tubing and it went very well with my final result being within 0.1 degree of the drawing specification. Given the subtle. compound angles involved here, I'm quite proud of that.

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Mon Apr 23, 2012 8:32 am 
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Wow, Lonnie! That looks very, very good! I really like the "star" of small tubing forming the supports inside the basic shape, very Caterham-ish! And the fitment of all those compound angles is just amazing! Good design, thoughtfully set up and well executed. In short... DAMN! :mrgreen:

:cheers:
JD Kemp

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JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


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PostPosted: Mon Apr 23, 2012 10:59 am 
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GonzoRacer wrote:
Wow, Lonnie! That looks very, very good! I really like the "star" of small tubing forming the supports inside the basic shape, very Caterham-ish! And the fitment of all those compound angles is just amazing! Good design, thoughtfully set up and well executed. In short... DAMN! :mrgreen:

:cheers:
JD Kemp


Thank you very much, JD. You're a gentleman and a scholar, as my Irish grandmother would say. Coming from you, I take it as a high compliment.

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Mon Apr 23, 2012 8:37 pm 
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Anyone out there really good at welding in tubes? I'm practicing welding 0.75" (19.05 mm) tubes onto RHS so I can finish my front frame. I've kept my samples small and can look at the metal surrounding the joins in into the tubes and see that my penetration and bond are good. Now, I want to make them look pretty and be strong too.

It just came to mind that doing the welds as 4 arcs around the perimeter would be good to try. I'm able to get pretty good body English that way, but my overlaps look kind of sloppy (examples below). So, I have three questions to anyone out there who can do these well with a MIG welder:

1) What is your strategy for doing the welds? Is doing 4 arcs a good way to go?

2) How do you make your start and stops blend together so they look continuous and not lumpy?

3) What about large angles where the tube and RHS ar really close together? How do you handle that real squeezed-down gap?

Thanks,

Lonnie

PRACTICE EXAMPLES:

Attachment:
File comment: Basic problem- weld tubes to RHS
Weld-Sample-1.JPG
Weld-Sample-1.JPG [ 591.87 KiB | Viewed 469 times ]


Attachment:
File comment: Example of my 4-arc strategy.
Weld-Sample-2.JPG
Weld-Sample-2.JPG [ 697.48 KiB | Viewed 469 times ]


Attachment:
File comment: I'd like to overlaps to be more continuous. I know these are strong enough, but could look much better.
Weld-Sample-3.JPG
Weld-Sample-3.JPG [ 689.1 KiB | Viewed 469 times ]

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Mon Apr 23, 2012 8:53 pm 
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When welding around the tubes i would as few starts and stops as possible i try and aim for 1/2 to 2/3 of the tube. But in the locost frame that can be pretty much impossible due to the tight space so 4 sections does not seem too bad. In order to blend your starts and stops i would take a thin grinding or cutoff wheel and tapper or "feather" the weld where you had started the weld in order to make a smooth transition. When you weld i would back step the weld, or weld to were you stoped allowing you to grind off and burn out the cold start of the weld each time. In the tight gap due to the sharp angle i find it easier to start the weld outside of the tight gap were you can establish a puddle and then pull the puddle into the narrow gap. I hope that this is understandable it is a hard thing for me to explain if it does not make sense maybe i can draw a picture.


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PostPosted: Tue Apr 24, 2012 12:21 pm 
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WelderLee wrote:
. . . <snip> . . .

When you weld i would back step the weld, or weld to were you stoped allowing you to grind off and burn out the cold start of the weld each time.

. . . <snip> . . .

I hope that this is understandable it is a hard thing for me to explain if it does not make sense maybe i can draw a picture.


The "back step" part is the only thing I don't understand, Lee. I wouldn't want to take up too much of your time, but if you think a sketch would be helpful, feel free to post one.

Thanks,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: Tue Apr 24, 2012 2:24 pm 
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Ok i thought of an easier way to explain back stepping. If you imagine you were looking down on the weld like the face of the clock first you would weld from 12 to 3 and then you would back step and weld from 9 to 12 then you back step again and weld from 6 to 9 and then lastly you would weld from 3 to 6. In between each weld you would feather were you started the weld and then self over were you feathered it. For the last weld you want were you started and stopped to be fathered. This is the strongest way to weld this type of joint although all the grinding makes it time consuming. A fun little experiment is to weld up a box with MIG and see if it will hold air, you will find that feathering the tacks and back stepping is one of the only ways to weld that pressure vessal without having leaks.


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PostPosted: Wed Apr 25, 2012 6:11 am 
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Hi Lonnie,
Your work looks OK and I am an experienced welder but more used to thicker section. My experience with this small stuff is that it is hard but easy? It is hard to make it look good because the very nature of MIG means you use more filler wire than needed but it is easy because it is hard not to get penetration and in most cases your weld will be stronger than the parent material. Think about it, you make a fillet weld that is about 3mm thick yet the material you are welding is only 1.6, if you break one of these welds it will always break at the edge of the weld. You seem to obsessed with getting a perfect and while I admire your need for perfection it is not the end of the world if you have a little gap. The MIG will handle that easily. If you were TIGing or brazing then it is better to have a perfect fit but no need to worry with the MIG. In regard to welding around the round tube, it is not easy. One tip that professionals get taught is to start in the most uncomfortable position and weld through the comfortable to finish uncomfortable and in this way you may get around half the tube. To maintain the correct angle you have to move quite fast as your weld may only be 25-30mm but you hand has to move 200-300mm, for a half circle on 3/4 tube. The acute angle is difficult and the advise to weld into it is good, but again, especially because of the angle, you will have more weld around it than the strength of the tube, so if you miss a little it is no big deal. I found an old shroud and flattened it a bit it also helps to turn the gas up a little and with a longer wire length you can compensate by turning up the amps a step.
I like your trianglation except the tube that runs to the middle of the top tube is unnecessary, unless of course you have something in mind that we don't know about. The reason I say this is that it does not intersect at a node as it should.
I have to agree with you about the "U" shaped brackets and I have attached an image of the lower ones of mine under construction. If you are interested I need to take some of the finished article, I thought I had but can't find them.
Bruce


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