LocostUSA.com

The idea comes from McSorley's build, www.sevenesque.com . I haven't seen the slider boxes used yet on a Locost type chassis but, I did find this build who used that style bolt in control arm here http://texaslocost.homestead.com/Suspension.html . Although I am thinking of moving away from the slider boxes. The execution of the idea seems to complicate it a little bit. Using a McPherson style spindle I can move the upper ball joint nearly anywhere to account for any changes I might need to make after the fact...

What do you think about mounting high strength rod ends horizontally instead? I know mounting 'em that way they're only supposed to see something like 10% of their rated load, but spacing the brackets with about 2 inches or so of space in between and using spacers at different lengths would give a bit of up and down movement. I started messing with the concept in the screenshot below. Braced and boxed off they might be good?




Thanks.

As far as mounting 'em in the wheels, I did mount them to the hub face, then offset the wheels out 8mm for the thickness of the rotor hat. Beyond that I still am unfamiliar with making the groups and measurements and creating layers and such (like the wheelbase/track measurements you mention changing with model changes). For now, I usually just hide what I don't want to see temporarily...

Actually that image was the first one I found that showed the control arm mount being supported by only one bracket and that's why I chose it but, I did not know that little tidbit, and learned something there.

I agree that it's elegant in how it uses one bolt to do multiple jobs, so it all comes down to what's most important. If a raising rate setup can be had with the upper mount right near the upper pivot bolt, practicality should be allowed to win out and one bolt used - none of this stuff is black and white. Just the fact that you're building something that weighs less than half that of most cars virtually insures high performance.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

I don't suppose keeping the slider boxes and mounting an arm like so in the picture would be very nice on 1/2in grade 8 bolts 'eh?

https://3dwarehouse.sketchup.com/model. ... a368673337

Finished the EJ205, it was pretty dang close to the box model so, it looks like the rear will need an entirely new redesign.

Would there be anything negative with moving the entire engine/trans assembly down an inch, which would angle the CVs upwords from the transmission to the spindle at ride height?

You want to keep the axles level as possible. That was a big issue I had with my diff. In order to keep the axles level I had to raise the diff almost 4 inches off the frame. A couple degrees of angle is fine but nothing more then 6-8*.

_________________
30 years old, not sure what I want to be when I grow up…

Gotcha. I think 1 inch down is inly 3-4 degrees total






Has a Car9 frame or a middy car 9 frame ever been completed? The more I keep looking at trying to reuse the bits of the 442 already created, the less I really like it. I am having a hard time deciding on the rear susension

I'll import your motor into my copy of your model and do a little bit of the other stuff I mentioned. Your right on the angle of the driveshaft, but you should also account for bump travel.

My thought on an initial approach to the frame around the motor is the rear is to allow for the motor to be dropped out the bottom by making the bottom frame rail bolt on. That's how my formula car was designed. The shape of this motor is good interns of not being long, but it is wide so we'll need to compromise somewhere.



I was on the fence wether Car9 would be midship or not when I started the drawings and stress analysis. Tom Heltzall was the first builder that committed to metal and he wanted front engine. That seemed a more basic and direct approach because I was having trouble choosing transaxles and power plants for the midship design so I choose to support Tom and make sure the ball got rolling. Tom has been a patient, conscientious, consistent and supportive builder. His frame is complete and he is designing the details in his suspension, it looks like he is going to make a lot of progress over the next weeks.

My frame is also front engined and I am working on welding in the rear bulkhead, all the other large tubes are in. Briggs is very interested and is working on drawings and setting up his build shop and welding equipment. There are a couple of other interested parties. I would very much like to see the midship version get under way. Where you are now is most of the way towards the Car9, we just need to work out the rear of the car. There would also be a little adjusting of the cockpit tubes because I prefer a single upper rail which is just a bit higher. It makes for more occupant protection and general strength.

The one missing piece is that I would like to see a model made for the stress analysis. I just feel better when it's possible to answer questions about how strong it is or how much load there is on a tube. This is not difficult, basically we need to find the location of the joints between the tubes. It's actually a lot of fun and I am willing to help a lot with this, but would appreciate some effort at your end. It's easier than learning SketchUp, there is no drawing involved. Mind you having the FEA model gives you plenty of answers, it's up to us humans to understand those answers and also to ask the right questions!

Having both of these models should give you good peace of mind going forward...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

I was actually playing around last night with the engine model inside your Car9 last night. It's a tight fit but, it looks like it would work. I was also playing with a potential square tube version of it. I do not have a bender so, square tube appeals to me but, it doesn't look as good.

I just don't see a way to created the 442 rear frame as a midship while keeping the angled rear bulkhead as with the original front engine design, seems to make any bracing extra complicated and if you're going to get rid of that, you might as well start fresh. I think many people have come to this conclusion as well (the Midlana for example).

Missed this part, just lemme know what to do and I'll link 'em up. Do you just draw through the centers of each tube?

I replaced most of the round tubing in the midi version and did a little cleanup. It needs some more. When I grabbed your engine model somewhere I have lost track of the transmission. So I need that to see where the rear wheels go. I started to put in a rear bulkhead for the suspension. I also need to know where the motor mount and transaxle mounts go.

Briggs is also interested in doing a square tube version, so it's a common and sensible idea. I'd like these to be easy to build, they shouldn't be hard.

We need to think about the wheelbase. In this drawing I seem to have neglected to allow for steering of the front wheels.

Here's the Car9 Midi with your engine and converted to square tube with the start of some rear end tubing.
https://3dwarehouse.sketchup.com/model.html?id=ue9c6565a-3c1f-4725-acf9-26cb24e9d90a

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

I'm bushed for today, I'll post some more details tomorrow.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Yeppers, brought home the rest of my tools today. Now gotta do some organizing in the garage. I would really like to start my build no later then November if at all possible.

Im working on a square tube version on Marcus' Car9 design with the roll cage bits and rear of the car in DOM tubing via scca roll cage specs. Im also using a R1 power plant with a prop shaft and a suby diff. My goal is to keep the car around 900 lbs if possible but deff under 1000 lbs.

I thought about doing a middy as well but, I wanting to use an R1 engine and not be chain driven. I decided on the FR setup, plus I'm a sucker for the original lotus and caterham look. Also helps that Tom is already done with his frame. If you haven't gone threw Tom's build thread you need too. Tom's skills are simply amazing and his attention to detail is mind boggling.

Marcus have you started on yours? I dont recall seeing any pics other then the one of the materials.

Great work on the engine BTW. Also, is the suby trans really that large? It looks way bigger then the engine in the model.

_________________
30 years old, not sure what I want to be when I grow up…

The motor mounts are literally in line with the rear face of the motor that mounts to the transmission. I don't have extra mounts here to model but, the bottom left and right corners where the motor mounts to the transmission are close. Found this image on Google so you can see a visual of the angle they come out at.



You can see in the picture where the mount bracket butts up to where the transmission mounting face is and then in this picture below you can see the mount it's self offsets forward about 2-3 inches from there.



It may be easier to design the upper roll bars as well as the rear upper horizontal frame bar to be removable and just remove the motor/transmission from the top.

I added my basic transmission model started messing with the rear frame to work around the turbo and where the turbo downpipe should be. If I get anything significant I will upload it but, I get married tomorrow so, probably won't have much time this week to mess with the model. I do want to create a more accurate transmission model though since the dimensions of mine are a slightly larger then actual (but the mount position is accurate). I uploaded the basic dimensions transmission, the lower square in the rear is where the mount is.

Basic Transmission https://3dwarehouse.sketchup.com/model. ... caa1802439




It's the square shape that makes it look a little larger then it actually is, and that I rounded up when making the model to give a little extra room. But, the engine mounting face is 15x15.5ish, the transmission is a good 26inches long, and that's not including the tailshaft section and the height from the bulge at the bottom where the front diff is to the top of the trans is 17inches.

The motor from crank pulley face to transmission mounting face is only 16.5 inches but, it's 32.5 inches wide.

Here's another shot from google that shows the length.

Something also to consider when messing with the rear frame is the exhaust that is not modeled. The turbo up-pipe sits almost parallel to the engine mount.