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McG-01 design phase
http://www.locostusa.com/forums/viewtopic.php?f=53&t=9723		 Page 2 of 5
Author:  RbBugBitMe [ July 30, 2010, 4:15 pm ]
Post subject:  Re: McG-01 design phase
Thanks for the input but ITS MY CAR AND I'LL DO IT HOWEVER I WANT! :wink: As I said before this is mostly an engineering exercise for me even though the end goal is a reliable daily cruiser. So I'll stick with a stock motor for now and donor or off the shelf drivetrain parts but I want to learn a few new things that I've never done (carbon fiber design and analysis is one) and I also want to redo some things I have already done (design and FEA uprights, design my own rotors/hats and pedal box) because it is just the area of the car that I enjoy working on the most and there will be a huge smile on my face if I can create a reliable upright that can handle Pittsburgh city potholes and a 600+ mile round trip to the beach.

I've gone through a lot of brake calcs already but I want to verify and refine them before I post anything. Next, I think I'm going to create a SolidWorks assembly and let CosmosMotion tell me the loads I'm going to have to design for based on my ASSumed input loads at the tires. Should be interesting!
Author:  DeanD3W [ August 9, 2010, 6:20 pm ]
Post subject:  Re: McG-01 design phase
If you want to register the car for the street, have you checked on how that will work in your state? In Washington, a car like you have planned would have to meet 2010 production car emissions standards... Since it will not resemble an older car, like a 7, 11, 23, Cobra, street rod, etc, they would register it here as a brand new 2010 model. I hope your state works differently, or maybe you have just a track day car in mind?
Author:  JonW [ August 9, 2010, 6:51 pm ]
Post subject:  Re: McG-01 design phase
PA cars registered as "Special Construction" are emissions exempt. Safety inspection only.
Author:  RbBugBitMe [ August 9, 2010, 10:00 pm ]
Post subject:  Re: McG-01 design phase
EDIT/UDATE: I had all the information before, including the special inspectors training manual, but I will have to find it all again. From what I remember JonW is correct. When I find the info again I'll post it up in the correct forum.

As for how my design is going, it is looking like I may be able to stick with 13" wheels based on my braking assumptions. I was hoping I could stick with 13" wheels so that when I went racing I could use the tires that I have tire data on from FSAE and really design my suspension to them. It's not a huge deal but it would be nice.

Here are my assumptions so far.

1400lb weight with driver
45/55 weight distribution
17" CG height
102" wheelbase
1.5 G max braking force
24.9" O.D. Continental ExtremeContact DW tires

I started doing hand calcs but to move things along quickly I'm just using Jake Latham's calculator which I'll verify the numbers on later once I get close to the setup I think will work.

Right now it is working out nicely with....
1.75" front 4 pistons, 1.25" rear 4 pistons
0.7"/0.75" front/rear master cylinder diameter
0.65 mu brake pads (racing only)
11.75" rotors front and rear
1.60" radial pad height
No offset from center toward the front master cylinder on a 3" separation
658/567 PSI front/rear line pressures

This is with a 105lb input pressure and 6.2:1 pedal ratio.
Author:  RbBugBitMe [ August 9, 2010, 10:23 pm ]
Post subject:  Re: McG-01 design phase
EDIT/UPDATE: A quick Wilwood search has found the Dynapro Radial Mount series has front and rear calipers that match my description above for up to 1" thick rotors.

I've found some 10.25" vaned rotors that may fit with the Dynapro's in 13" Jongbloed wheels.
Author:  RbBugBitMe [ August 10, 2010, 1:24 pm ]
Post subject:  Re: McG-01 design phase
After searching around on here I'm pretty surprised to see how low people assume their CG is. I've adjusted my theoretical setup accordingly again using 17".
Author:  KB58 [ August 10, 2010, 3:44 pm ]
Post subject:  Re: McG-01 design phase
No assuming necessary if a spreadsheet's done. Mine says my non-Locost but equally low car has a CG of about 16".
Author:  RbBugBitMe [ August 10, 2010, 3:51 pm ]
Post subject:  Re: McG-01 design phase
I'm just not that far along yet, good news though!
Author:  cheapracer [ August 11, 2010, 5:34 am ]
Post subject:  Re: McG-01 design phase
RbBugBitMe wrote:

I've found some 10.25" vaned rotors that may fit with the Dynapro's in 13" Jongbloed wheels.


They will fit no problems. Oh, did you want to use calipers as well? They make brakes much more effective.
Author:  RbBugBitMe [ August 11, 2010, 8:12 am ]
Post subject:  Re: McG-01 design phase
cheapracer wrote:
RbBugBitMe wrote:

I've found some 10.25" vaned rotors that may fit with the Dynapro's in 13" Jongbloed wheels.


They will fit no problems. Oh, did you want to use calipers as well? They make brakes much more effective.


In the same post you quote....

RbBugBitMe wrote:
EDIT/UPDATE: A quick Wilwood search has found the Dynapro Radial Mount series has front and rear calipers that match my description above for up to 1" thick rotors.

I've found some 10.25" vaned rotors that may fit with the Dynapro's in 13" Jongbloed wheels.
Author:  KB58 [ August 11, 2010, 9:43 am ]
Post subject:  Re: McG-01 design phase
RbBugBitMe wrote:
Thanks for the input but ITS MY CAR AND I'LL DO IT HOWEVER I WANT! ...

I know the context of how you meant this, but it doesn't matter if you want to drive it on the street. There are all sorts of local laws that have to be checked out, else you can indeed build whatever you want - and never be able to drive it on public roads.
Author:  RbBugBitMe [ August 11, 2010, 10:09 am ]
Post subject:  Re: McG-01 design phase
I'm aware.

http://www.dmv.state.pa.us/inspections/pub_45.shtml
http://www.dmv.state.pa.us/pdotforms/ve ... pter13.pdf
http://www.dmv.state.pa.us/pdotforms/pu ... tion_k.pdf
http://www.dmv.state.pa.us/pdotforms/fa ... ehicle.pdf
Author:  RbBugBitMe [ August 13, 2010, 5:27 pm ]
Post subject:  Re: McG-01 design phase
Yesssss. I'm all jacked up on mountain dew and ready to get some modeling done tonight.

I just got off the phone with Taylor Race. Looks like I'm going with a custom hollow half shaft and tulip style one piece stub axles.

Agenda for the night...
1) Start the suspension design
2) Start modeling the wheel assemblies
3) Curse at myself for not having dual monitors yet
Author:  RbBugBitMe [ August 14, 2010, 2:24 am ]
Post subject:  Re: McG-01 design phase
It's been a little slow. Made the decision to go up to 16" wheels so I picked out what I wanted with tires and redid the brake calcs.

Design updates:
102" wheelbase
62" front/60" rear track
Modeling done with dimensions from Enkei RPF1 16x7 25mm offset and Continental ExtremeContact DW 225/50-16
11.75" rotors all around
Wilwood Dynapro radial mount 4 pistons 1.75" front/ 1.25" rear dia.
0.7" front/ 0.75" rear master cylinders
6.2:1 pedal ratio and an estimated 105lbf input

After clearancing the caliper from the conservatively (I hope?) dimensioned spokes I may step up to the 35mm offset. Otherwise my caliper and bearings will be to far inboard of the wheel centerline. I must say that these wheel companies are really pissing me off. There is no reason why they shouldn't be able to provide the depth from the hub mount to the inside face of the spokes so I can better place the caliper/upright.

The CAD model doesn't have any suspension geometry yet but I have started it in WinGEO.

First night... 189lbs total, 12.45" CG height

Image
Image
Author:  kikiturbo [ August 14, 2010, 11:02 am ]
Post subject:  Re: McG-01 design phase
hi,you might want to check my log as we have similar brake packaging issues...

I managed to squeeze 245 mm dia discs and 4 piston wilwood dynapro calipers under 13 inch wheels..

viewtopic.php?f=36&t=5899&start=75

the little excell file for calculating brake forces with various caliper and master cyl combinations is here : http://www.bib-nakladnistvo.hr/x1000/
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