Arc length / Geometry, Anyone smart?

78Class3
Posts: 120
Joined: Sun Dec 13, 2009 1:09 pm

Arc length / Geometry, Anyone smart?

Post by 78Class3 »

I've got all the #'s to solve this suspension geometry problem but don't have the brains to do it anymore. I'm looking for the length of B to B. I think angle Q is approx 11 degrees (but really not sure how i got that answer :D ). I've been plugging away at this for hours now and keep getting different answers. I want to know how far the coilover (B) will move if the limit strap(A) moves / bottoms out after 2". :mrgreen: It is 10" further away from the pivot point (0) being the radius arm hiem joint. I think its crazy how i used to have to know this junk for tests in high school/college, I guess i should have paid more attention.hahaha
Attachments
Untitled.png
Untitled.png (13.16 KiB) Viewed 914 times
User avatar
Copykat
Posts: 242
Joined: Thu Dec 10, 2009 7:37 am
Bronco Info: 1987 BroncoII 4x4
Location: Manitoba Canada

Re: Arc length / Geometry, Anyone smart?

Post by Copykat »

Q is actually 3.4°

for 2" travel at A-A travel at B-B is 2.6"

CAD is an awesome tool. No math required.
1987 BroncoII 4x4
User avatar
Phoenix0783
Posts: 658
Joined: Thu Dec 10, 2009 12:50 pm
Bronco Info: No more Bronco :(
Location: Bend, OR
Contact:

Re: Arc length / Geometry, Anyone smart?

Post by Phoenix0783 »

Just take the ratio of the two distances and multiply by how much they move.
OB/OA * 2 = 2.6"

You can flip OB and OA if you want to know how far A moves if B moves 2 inches.
My car is a hybrid; it burns gas and rubber.
78Class3
Posts: 120
Joined: Sun Dec 13, 2009 1:09 pm

Re: Arc length / Geometry, Anyone smart?

Post by 78Class3 »

aaahh, thanks guys. I acutally had Q of 3.4 from one formula but got the 11 from another. Looks like i need a longer limit strap. Thanks again
trophygirl
Posts: 27
Joined: Wed Jul 20, 2011 11:35 am
Bronco Info: 2002 Ford Ranger Prerunner

Re: Arc length / Geometry, Anyone smart?

Post by trophygirl »

Your second limit strap is less than .6" longer than the first?
trophygirl
Posts: 27
Joined: Wed Jul 20, 2011 11:35 am
Bronco Info: 2002 Ford Ranger Prerunner

Re: Arc length / Geometry, Anyone smart?

Post by trophygirl »

Oh, wait. You just want your coilover to travel more...?
78Class3
Posts: 120
Joined: Sun Dec 13, 2009 1:09 pm

Re: Arc length / Geometry, Anyone smart?

Post by 78Class3 »

Yes, i need a longer limit strap at A so that the coilover (B) will have more droop.
User avatar
PaulW
Posts: 1599
Joined: Wed Dec 09, 2009 8:56 am
Bronco Info: Modified and Linked 1972 Bronco

Re: Arc length / Geometry, Anyone smart?

Post by PaulW »

Copykat wrote:Q is actually 3.4°

for 2" travel at A-A travel at B-B is 2.6"

CAD is an awesome tool. No math required.
=========
Confirmed from the math handbook . The arc length is 2.606"
PaulW
User avatar
ChaseTruck754
Spy/Ninja
Posts: 9194
Joined: Thu Jan 28, 2010 9:46 am
Bronco Info: Don't have one - just old Ford trucks
Location: Huntington Beach, CA

Re: Arc length / Geometry, Anyone smart?

Post by ChaseTruck754 »

Copykat wrote:CAD is an awesome tool. No math required.
Yup - I LOVE the fact that I had to learn it for work when it comes in handy for fun, truck stuff like this. I use cad all the time to solve math problems I lack the brains to do the "real" way...
Owner of only dead and forgotten projects
shockseals.com
Posts: 1116
Joined: Wed Feb 17, 2010 11:50 am
Location: San Dimas
Contact:

Re: Arc length / Geometry, Anyone smart?

Post by shockseals.com »

I am late to the party but a quick scan I didnt see an arc length formula, just answers.

S=R X Theta
S is arch length
R is leg
Theta is angle in radians
Kris Hernandez
shockseals.com
shockseals.com
Posts: 1116
Joined: Wed Feb 17, 2010 11:50 am
Location: San Dimas
Contact:

Re: Arc length / Geometry, Anyone smart?

Post by shockseals.com »

Phoenix0783 wrote:Just take the ratio of the two distances and multiply by how much they move.
OB/OA * 2 = 2.6"

You can flip OB and OA if you want to know how far A moves if B moves 2 inches.

Remember that this works for right triangles only...
Kris Hernandez
shockseals.com
User avatar
Phoenix0783
Posts: 658
Joined: Thu Dec 10, 2009 12:50 pm
Bronco Info: No more Bronco :(
Location: Bend, OR
Contact:

Re: Arc length / Geometry, Anyone smart?

Post by Phoenix0783 »

shockseals.com wrote:
Phoenix0783 wrote:Just take the ratio of the two distances and multiply by how much they move.
OB/OA * 2 = 2.6"

You can flip OB and OA if you want to know how far A moves if B moves 2 inches.

Remember that this works for right triangles only...
True, but with that small angle, it ends up being close enough.
My car is a hybrid; it burns gas and rubber.
Post Reply