LocostUSA.com

Here's one of the changes that I'll put into my next frame.
Rather than bending the main hoop as I did, simply stretch the floor back a bit more and have a normal hoop just like yours going straight to the floor.
There's no reason not to do it packaging-wise, and AFAIK the floor can be stretched back far enough to get the hoop almost perfectly vertical which is good enough.
The access to the front bolts of the LCAs can be done from inside the car if necessary, behind the seats.

Moti

_________________
Moti

My R1 powered Locost build log

Visit the Blackbird Fabworx Facebook Page!

Forgot to mention, in your computer model it shows the vertical pieces that the SRA cars have, since you're building IRS car you may want to do them the right way for IRS car, as marked in yellow on the diagram.

Moti

_________________
Moti

My R1 powered Locost build log

Visit the Blackbird Fabworx Facebook Page!

One suggestion based on your model Devin: you may need to rotate the front upper arms' rod-ends so the bolts are going fore/aft instead of vertical or plan for high misalignment rod-ends.

I tried your arrangement with my car and regular (not high misalignment) rod-ends did not have enough travel.

I was able to orient the bolts vertically on the bottom arms but they just barely have enough travel.

_________________
-Andrew
Build Log
Youtube

Thanks for the feedback guys!! I had not thought of extending the floor rearward and keeping the hoop vertical. Perhaps for the next build...

The short vertical tubes just in front of the rear wheels will not be vertical in the real chassis- they will tie into the corner just behind where the are in the CAD model. The horizontal tubes just above those will be angled down in the rear slightly for more elbow clearance but the model still shows them as horizontal.

I plan to use the high misalignment rod ends from QA1 in the front to get the range of motion needed. I will also reinforce the lower, rear pickup point on the front a-arms when I get that far. That will be fabbed up on the fly...

The rear section of the frame still needs some work in CAD before I fabricate too much more there. I need to get more dimensions on the rear diff and figure out where to locate it for sure.

_________________
build log: viewtopic.php?f=35&t=11946

If you haven't made any progress with the real chassis you're only going to need to re-do three tubes and two plates at this point... piece of cake.
C'mon Devin, you know you want to do it

FWIW, I got the QA1 high-mis rod ends for my control arms and bought a few more rod ends for other things from QA1.
The high-mis REs came nice and tight but the other REs were so sloppy that I couldn't use them.
Unfortunately, by the time I actually noticed the problem I couldn't return them anymore and I had to buy more REs.
The next set I bought was from FK bearings and they came perfect.
Bottom line, check your rod ends when you receive them.

Moti

_________________
Moti

My R1 powered Locost build log

Visit the Blackbird Fabworx Facebook Page!

Good tip on checking the rod ends for slop when I get them. Does FK have decent prices??

I think I am going to stick with the chassis the way it is currently. I am a little further along than the pics show.

_________________
build log: viewtopic.php?f=35&t=11946

I got a bunch more things on the same purchase and don't recall the breakdown exactly, they were'nt too bad though, not like Aurora or something...

Moti

_________________
Moti

My R1 powered Locost build log

Visit the Blackbird Fabworx Facebook Page!

Found some more time to play in the garage and cut the front control arm mounts out. The jig saw with a bi-metal blade made pretty quick work of the 1/8" plate. I also made some custom spacers to get the tabs properly located.

I will need to re-fab the top tab as there is too large of a gap for my welding skills to fill on the one side.


The plumb bob seemed to be the best way to locate the mounting hole in the X and Z planes according to the Wishbone dimension scheme.

As I started working through fitting the tabs, I realized that my CAD model and the angles of these tubes are a little off so I will have to re-fab several of the tabs.

_________________
build log: viewtopic.php?f=35&t=11946

Looking good. Nice work with the jigsaw on those tabs.

It looks like you have about 1D of edge margin on those tabs (1 bolt diameter from the center of the hole to the edge of the tab). Unless you have done the math to verify that the bolt won't shear through the edge of the tab, you may want to redo them and leave more material.

Have you checked to see if the bolt being oriented vertically will leave you with enough rod-end travel? I originally had my uppers and lowers oriented that way - the lowers were fine but I had to redo the uppers and make the bolt face fore/aft. High misalignment rod-ends or high misalignment spacers probably would have fixed it.

_________________
-Andrew
Build Log
Youtube

Hi
Your work is looking great. A couple of thoughts though. Firstly I like to see the brackets radiused as it looks nicer than square ones and also the square bits are only excess weight. Second I notice that your chassis is only tacked. It is normal practice to fully weld the chassis before fixing the suspension bracket as any distortion in the chassis can be allowed for when you weld on the brackets.
Bruce

Thanks for the feedback, guys. It is always appreciated.

Andrew- Good point on the bolt holes being on the close side to the edge of the part. I can adjust that on the ones I have to re-fab and may re-fab the others as I get time but may wait until I test fit the control arms to the chassis, when I get that far. I should have plenty of motion available with the high-misalignment rod ends I plan on using.

Bruce- I am only tacking the chassis so I can make adjustments as I go. I am also of the opinion that if more of the chassis is tacked together, it will resist warping when I fully weld everything. I will be careful to only weld small bits at a time and jump around on the chassis to not put too much heat into any one joint.

Here are more pics from last night...





This would be a lot easier and more fun with a plasma cutter...

_________________
build log: viewtopic.php?f=35&t=11946

> plasma cutter

I once saw an interesting setup - a plywood frame holding a circular saw up at 90 degrees, with a notched table in front of it. That is, the blade extended well out into the table, which was cut for clearance, like a bandsaw table. The table was plywood too.

The saw had one of the abrasive chop saw blades. Most of those blades have big "DO NOT USE IN A CIRCULAR SAW" warnings nowadays. Anyway, the guy just turned the saw on and proceeded to cut out, notch, and shape a chassis bracket in just a few minutes. I think the speed was mostly limited by the heat coming through his gloves.

It was way faster than my bandsaw and disc sander method, anyway...

Hey, that's a good tip. Thanks. Oriented like a grinder wheel. Would be very usfeful.

So a little progress was made in June that I have not had a chance to post.. Things get crazy in the summer with kid's activities and other diversions.


I have four of the front suspension mount brackets refabbed (lower, front brackets) but not tacked to the chassis yet.

Diversion #3: had to add an extra door bar to each side of the ITC CRX race car's cage, remount the window net so it drops down when released and then add an electrical kill switch in short order before a race a few weeks back.



Got the bars from Kirk Racing- they were very nice and helpful in getting the two bars out quickly. This was my first experience notching tubing and I was taking it super slow so I would not cut too much off and have to punt.

_________________
build log: viewtopic.php?f=35&t=11946

Got out in the garage and sure enough, I start cutting another bracket out with the jig saw and now it won't hold the blade anymore. Off to the hardware store for a new jig saw.

Got one more bracket roughed out but did not get pics.

_________________
build log: viewtopic.php?f=35&t=11946