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Starting a Locost Lotus from scratch


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Hey all. I'm new here and at the very early stages of planning a Lo-cost Lotus 7 project. In order to be better prepared, I bought the Ron Champion book, downloaded a set of plans to study. I have a few builds behind me but never a completely scratch built car. So I got to thinking before I invest in metal and materials I wanted to better visualize how the frame assembles. Since the crux of the frame is 1" x 1" sq tube, the idea hit me that 1/4" sq basswood sticks (available at the big box store) could be used to create a 1/4 scale frame for cheap. Please note the attached pic. Still a few pieces to add boxing in the trans tunnel and engine bay, but the basics are done.

 

http://www.usa7s.net/vb/attachment.php?attachmentid=13409&stc=1

I used the book plans and divided all the line dimensions by 4 and mitered the angles. Set up a center line on grid paper and laid plastic wrap over it so the glue wouldn't stick to the paper. For "Boot" area 1/4" dowels made for the round tubing bits. Overall it's over 2 and a half feet long and 10.5" wide. Came out pretty well and I have a much better idea of trouble spots and the assembly process. Plus when the full scale is done the 1/4 scale frame will show well with the car. The wood and a 10 gram bottle of CA type super glue cost under $20.00 and has created a valuable reference for when the steel cutting and welding starts. What do you think?

Frame.jpg

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Johnny

Nice start and the model will help in the planning and fab of the project! Search Ozzies mods, for added structural improvements to your typical Locost frame. Do you have a donor or have a particular donor you plan on using?

Where are you in SE Michigan. Dave W

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Very cool. I'd like to build something similar to hang on the wall. I have a Caterham SV so I'd like to find plans for that frame to make a wooden model.

 

Hey Nick-

Sweet you are already driving your Caterham. My first drive is still a build away.

 

So to make the frame, I just downloaded a .pdf file of "The Book Frame" then divided the straight line dimensions by 4 and cut the angles as noted with a complex mitre box. And glued it together. It was fair easy given I've built a load of Radio Control planes.

 

If you like to have one for your wall, I will build another and send it your way. My price would be $199.00 for a 1/4 scale wood frame. Interestingly the same amount of money quoted to me by Contractors Steel for the 1" x 1" steel tubing to construct the actual full size frame. Deal / Offer?

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I built a book frame from scratch and run it at track days and autocrosses here in the DC area. Champion’s book dimensions have lots of errors, but you probably know that. The free plans from http://sevenesque.com/plans are accurate (not sure if those are the plans you refer to). The forum link at locostusa.com is a great source for info. The only wood model I built before hand was for the front trapezoid part as it required compound angles. If I knew then what I know now, I strongly recommend you document what parts you bought, and their own specifics because after many years when you need to change or add, or fix, etc. it helps to source the dang thing. Good luck, have fun.

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Johnny

Nice start and the model will help in the planning and fab of the project! Search Ozzies mods, for added structural improvements to your typical Locost frame. Do you have a donor or have a particular donor you plan on using?

Where are you in SE Michigan. Dave W

 

Thanks for tips on Ozzie's Mods. Will see if I can add them to the 1/4 scale. No donor at this time. I plan on welding the front "A" arms as well and buying all the tabs and pivot points from local Dirt Track Supply. Three Linking the rear axle. Engine also TBD. Purist wants to find old Lotus Twin Cam or Ford 4. Maniac wants Small Block Ford with 8-Stack Fuel Injection. Still taking suggestions.

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Now that you mentioned it I believe the .pdf I downloaded was the sevenesque version. My Champion Book has still not arrived from Amazon....Dang drone musta got lost. Documentation of parts used is a great idea. Stands to reason the more custom the build the more complex the build book.

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So the Champion book was out of print when I built mine, or was priced at hundreds of dollars and offered as used by various people which defeated the locost mantra so I got a copy from the Library of Congress, took notes and returned it. Building the frame was the easy part and took about a year. All the thinking and decisions that go into the various bits that need attaching to it consumes much more time........with several life interruptions.....more like 4 years in my case.

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Fred, but look at you now, A driving god on track. :hurray: You may want to share how you solved the issue of the automatically synchronizing cardinal grammeters? :jester:

 

Seriously, Fred built a nice BEC that does real well out on track. Tom

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Awe shucks Tom. And w/r/t the grammeters issue, I resorted to an over abundance of malleable logarithmic casings and panendermic semi-bovoid slots in the stator. But of course you already knew that.

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  • 2 weeks later...

I hope you don't think I'm stepping on your toes with this but the model seemed like a nice idea/project while I'm waiting for my car to come back from the shop. Here's the one I built:

 

OlM139a.jpg

 

I actually had a fun time putting it together and as you point out, it illustrates where the problems will pop up if you went full size. Now I just need to find a good drawing of an S2 or S3 frame for my next model.

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