LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently May 31, 2020, 7:13 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 202 posts ]  Go to page Previous  1 ... 9, 10, 11, 12, 13, 14  Next
Author Message
PostPosted: March 1, 2020, 3:21 am 
Offline

Joined: January 27, 2020, 1:10 am
Posts: 7
Hey John. Really cool project you're working on. I think we had pretty similar ideas of the "ideal car" and I actually read the same book as you, but realized that without an engineering background I was in way over my head. Suspension design is where I got lost. That's when I decided a better idea for me was to use someone else's proven plans. Much respect for you doing it all from scratch! Where in Wisconsin are you? Might not be too far from me in Illinois.


Top
 Profile  
Reply with quote  
PostPosted: March 1, 2020, 8:08 am 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6656
No Belleville. The washers are there to keep the push rod clevis from hanging on the opening in the pedal if the adjustment puts them close to the pedal. Domed spring washer might work better but they are not usually "fender washers" with a very large od to a small id.

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447


Top
 Profile  
Reply with quote  
PostPosted: March 1, 2020, 9:22 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
Hi Ben, I'm a bit north of Madison, maybe 4 hours from Chi-Town. But I did see your build. I do have a ME degree, but frankly alot of this is just CAD work. Being able to "activate" the suspension in CAD is certainly nice to see all the camber, toe changes, spring rates, etc. I was inspired by the FSAE stuff and the BEC book to build from scratch. But it's going to take a while!

I did some experiments with "Hobby Grade" servos to control the shift drum directly and control the throttle. Throttle by wire might be good for your situation, but maybe your later model CBR already has it.

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."


Top
 Profile  
Reply with quote  
PostPosted: March 8, 2020, 3:06 am 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I'm working on my pedal puzzle box. What I've got so far are "channels" with 1/4" holes spaced 1/2" to allow pedal fore-aft adjustments. I'm not super pleased with how difficult it may be to "adjust" when everything is together (skin, steering column, etc.). Each pedal, gas, brake, clutch can slide fore-aft independently.

While playing around with pedal positions in the car, I'm noticing that the brake bias bar is a little bit in the way at full throttle-no brake. My foot (lower arch) hits it a little bit and I'm imagining with an adjuster cable going out to the left my foot would hit that too.

I'm not sure if this is a problem, but I was trying to get things adjusted so my foot is not "sliding" on the pedals as they are pushed. The best general arrangement seemed to be the lower pedal pivot as low as possible and have my heel as close to the pivot as possible and the bottom of my heel about the same height as the pivot.

I don't foresee having to do any heel-toe braking, but if I did I think I would want the throttle pedal back an inch or so from the brake.

I don't have an master cylinders yet, so I can't go too much further than this.

Thoughts? Potential problems? Dude you're doing it wrong?! haha


Attachments:
pedal_puzzle_box_01.jpg
pedal_puzzle_box_01.jpg [ 190.29 KiB | Viewed 4929 times ]
pedal_puzzle_box_02.jpg
pedal_puzzle_box_02.jpg [ 200.14 KiB | Viewed 4929 times ]

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."
Top
 Profile  
Reply with quote  
PostPosted: March 8, 2020, 11:27 am 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6656
The throttle pedal is much stronger than it needs to be. You only have to move the cable against its own liner friction and the butterfly against its own return spring. The pedal should always run out of travel first. I’d add an adjustable pedal full throttle stop where the pedal strikes the head of a 5/16 bolt with a jamb nut to hold the setting. This should help prevent a cable failure.

For return springs, consider cutting the center of the pedal tubes out to insert 180 or 120 torsion springs: https://www.mcmaster.com/springs

There is only the outer race built into the pedal and the bolt. You can grease the bolt for reduced wear but add some bits of metal around the bolt head to keep it from rotating back and forth with the pedal, sawing through the adjustable flanges. Double nut since you can’t torque it down since there is no positive stop/inner race tube to tighten against. Take a look at my tracker shifter. It uses what I described except I also have a nylon bushing.

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447


Top
 Profile  
Reply with quote  
PostPosted: March 8, 2020, 9:19 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I figured I'd remake the throttle pedal and use something smaller. I do have a delrin bushing at the bottom pivot in the brake arm. I was thinking of using nyloc nuts, but double nut sounds better.

I could have sworn I had some piano wire laying around to make some torsion springs, can't find it though...

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."


Top
 Profile  
Reply with quote  
PostPosted: March 12, 2020, 1:41 am 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I changed the mounting of the pedals, it just seemed like it was going to be impossible to get those horizontal nuts and bolts in once the master cylinders/mount were in and the whole thing was in the car.

So now I've got vertical studs coming up from the frame (cross members). And the studs are not quite so hidden under the master cylinders. The pedal assemblies will need to be lifted up over the studs to adjust them. I thought about having threaded holes instead of studs, but I thought it would be easier to get a nut onto the stud instead of trying to get a bolt in while trying to align everything.

It's got +-1.5"(total 3") of adjustment.

The darker metal in the render is all one weldment.


Attachments:
pedal_box_01.jpg
pedal_box_01.jpg [ 73.38 KiB | Viewed 4673 times ]
pdeal_puzzle_box_03.jpg
pdeal_puzzle_box_03.jpg [ 225.83 KiB | Viewed 4673 times ]

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."
Top
 Profile  
Reply with quote  
PostPosted: March 12, 2020, 8:44 am 
Offline
User avatar

Joined: July 17, 2008, 9:11 am
Posts: 5428
Location: West Chicago,IL
You are doing great job.

Is the mount tapped where the masters mount or the master cylinderss tapped? IIRC, the masters have clearance holes. If so you may have an issue actually inserting the upper bolts. If you move the maters in front of the mounting bracket, that would fix that. In addition, removing the master for service will be easier IMO.

On a 2nd note, have you thought about mounting the whole assembly on slides and using a lead screw for adjustment. That would be interesting, no? Not that adjustment will be done more than once.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE


Top
 Profile  
Reply with quote  
PostPosted: March 12, 2020, 2:02 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6656
You could use a plate on top then slot the slider so there would be no need to remove the hardware to adjust, just loosen. Thick flat or flanged thin red plate.


Attachments:
johnsinski ped adjuster.JPG
johnsinski ped adjuster.JPG [ 94.87 KiB | Viewed 4616 times ]

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447
Top
 Profile  
Reply with quote  
PostPosted: March 13, 2020, 12:54 am 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
Yea, I suppose it would more sense to have that main m/c mount plate behind the m/c flange. Good call.

And I like the slotted slider idea too.

It's kind of fun just winging it, looking for bits of scrap metal laying around to make something out of.

Thanks for the feedback!

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."


Top
 Profile  
Reply with quote  
PostPosted: March 18, 2020, 9:35 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I Finally got around to scanning my "hand carved" foam seat, pattern. I cleaned it up in CAD to make it smooth and symmetric. I added a lip around it and I've got it split up into 4" thick blocks of foam that will fit on my CNC.

I want to add belt openings into the CAD model as well as hard points.


Attachments:
seat3_01.jpg
seat3_01.jpg [ 27.47 KiB | Viewed 3566 times ]
File comment: Not my best angle
seat_foam_buck_01.jpg
seat_foam_buck_01.jpg [ 54.08 KiB | Viewed 3566 times ]
master147.jpg
master147.jpg [ 107.89 KiB | Viewed 3566 times ]

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."
Top
 Profile  
Reply with quote  
PostPosted: March 19, 2020, 11:11 am 
Offline
User avatar

Joined: October 24, 2008, 2:13 pm
Posts: 4151
Location: Carlsbad, California, USA
Nice work on the seat. What device/software did you use to scan your hand built model? Was the model full scale?

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


Top
 Profile  
Reply with quote  
PostPosted: March 19, 2020, 5:11 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I built/carved a full size foam/wood buck until it fit me comfortably.

I used an old Microsoft Kinect with ReconstructMe to get a rough scan. Then import that .ply file into Meshlab to manually clean up any messy data. Then I export that as a .obj file and import that into Proe. It comes in very close to the right size and it's all triangle data.

So then I draw curves to build a nice clean wireframe and then surface that. There's lots of "license" in this process, haha.


Attachments:
seat_scan_process.jpg
seat_scan_process.jpg [ 73.43 KiB | Viewed 3419 times ]

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."
Top
 Profile  
Reply with quote  
PostPosted: March 23, 2020, 3:49 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 181
I still got brakes on my mind. The weight balance of the car is about 45/55. I'm planning on putting 235 tires on the front and 255 on the back. My front calipers are 2.4 in^2 each and the rears are 2.0 in^2. I bought one master cylinder so I could finish my pedal box, It's a 3/4" bore, so about .44 in^2.

I'm thinking when I get the other master cylinder that it would be about right to get another 3/4" bore and the bias bar should be enough to fine tune it.

Thoughts?

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."


Top
 Profile  
Reply with quote  
PostPosted: March 23, 2020, 5:42 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6656
The idea is to stagger the bore sizes so about right (but fine tuneable) will be equal pedal pressure across the bar but (typically) lower line pressure to the rear. Since you have 3/4, I'd go with 7/8 on the rear.

I'm guessing fixed calipers with 4 pistons? Floating doubles the area so you count the pistons twice when on one side.

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 202 posts ]  Go to page Previous  1 ... 9, 10, 11, 12, 13, 14  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 16 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY