RC-Monster Forums  
RC Monster

Go Back   RC-Monster Forums > Support Forums > HPI Savage

Reply
 
Thread Tools Rate Thread Display Modes
Rear Anti Squat, any one experimented?
Old
  (#1)
rcs2022
RC-Monster Carbon Fiber
 
Offline
Posts: 116
Join Date: Apr 2011
Rear Anti Squat, any one experimented? - 09.20.2012, 03:05 PM

Any one out there experimented by leaning back the rear bulkhead to attain some anti squat? Or is it that since the hinges are parallel one cannot achieve anti squat?
Any advantages in doing so from a theoretical point of view?

Having extended my Flux to XL length and added a center diff, the beast still wheelies! And as i am in my second design stage to include a custom designed TVP was checking to see if it is worth the hassle to include?
   
Reply With Quote
Old
  (#2)
crazyjr
RC-Monster Dual Brushless
 
crazyjr's Avatar
 
Offline
Posts: 3,786
Join Date: May 2005
Location: georgia
09.25.2012, 02:40 PM

Quote:
Originally Posted by rcs2022 View Post
Any one out there experimented by leaning back the rear bulkhead to attain some anti squat? Or is it that since the hinges are parallel one cannot achieve anti squat?
Any advantages in doing so from a theoretical point of view?

Having extended my Flux to XL length and added a center diff, the beast still wheelies! And as i am in my second design stage to include a custom designed TVP was checking to see if it is worth the hassle to include?
If you are still getting wheelies, adding anti-squat will make it worse. Anti squat raises the front of the arm in relation to the rear, I think it sort of changes the the moment of inertia higher on the chassis. I believe it will make your problem worse, I'm not sure if an RC-Monster center diff will work, but you could use a lighter oil in your diff to help with it. what voltage are you running? 6s is almost uncontrollable in any chassis


Work because i gotta, play because i wanna

People here hate Nitro, I love it. I start it, run it about 50 ft from me and it dies, I go after it. Perfect exercise
   
Reply With Quote
Old
  (#3)
rcs2022
RC-Monster Carbon Fiber
 
Offline
Posts: 116
Join Date: Apr 2011
09.25.2012, 04:35 PM

Thanks crazyjr for your feedback, I know anti squat should reduce wheelies, but with other tradeoffs obviously, this is an extract from HPI Glossary HPI Glossary

Quote:
Anti-squat -- Refers to the angle of caster on the rear wheels. However, that angle prevents the squatting of the rear suspension, so 'anti-squat' it is. Anti-squat is most effective on acceleration from a stop, when much of the car's weight is forced onto the rear suspension. Lifting the front of the hingepin of the rear arms gives a caster (anti-squat) angle, and helps to transfer the power that makes the car want to do a wheelie into forward motion.
You are right,
Quote:
Anti squat raises the front of the arm in relation to the rear
but this should change the location of the instant center relative to the center of gravity and in a way should prevent squatting and transfer some of the load to the front wheels, hence less wheelies; i'm no expert but this is what i summed up after reading numerous web pages.

I'm trying to comprehend it more to see if i can incorporate it and do some tests. The issue is that the savage pins on the bulkheads which support the upper and lower arms are parallel. Would just angling the whole rear bulkhead backwards be sufficient or is a change in the hinge pin angles needed also.

Most RC buggy cars have this adjustment by adding shims under the front edge of the rear bulkhead.

Its a long shot but i would like to go thru the hassle ;) Hope others have some insight or some pointers.
   
Reply With Quote
Old
  (#4)
rcs2022
RC-Monster Carbon Fiber
 
Offline
Posts: 116
Join Date: Apr 2011
09.25.2012, 04:42 PM

Forgot your last part of the message,
Quote:
but you could use a lighter oil in your diff to help with it. what voltage are you running? 6s is almost uncontrollable in any chassis
Yup, you nailed it, 6S and also with a Mamba XL2 on 1717. Thats why i wanna tone the front down but keep the power...

I already have 50k in the center diff, still wheelies, front tires balloon like crazy! Other members have advised to go up to 500 k in the center diff, but felt it voids the idea of the center diff to start with. Maybe with the high temps in the center diff (measured up to 90 deg C in 40 and above ambient) 500k or bit less is needed.

More experimentation and testing required, need to find the time...
   
Reply With Quote
Old
  (#5)
crazyjr
RC-Monster Dual Brushless
 
crazyjr's Avatar
 
Offline
Posts: 3,786
Join Date: May 2005
Location: georgia
09.25.2012, 07:40 PM

I understand your definition, but i was going from experience. in my case it made the wheelies worse. I had a traxxas SRT w/VXL/3500 setup, on a sandy track with level (0* antisquat 3* toe) it couldn't find traction. With 3.5* wedge (traxxas antisquat mount) it nearly flipped, The traction was so strong i couldn't run full throttle on the same track. Longer wheelbase and bigger truck, maybe it'll help. That setup you got there, I believe would be like putting a 2250 lehner in a CRT.5


Work because i gotta, play because i wanna

People here hate Nitro, I love it. I start it, run it about 50 ft from me and it dies, I go after it. Perfect exercise
   
Reply With Quote
Old
  (#6)
_paralyzed_
working on a brushless for my wheelchair.....
 
_paralyzed_'s Avatar
 
Offline
Posts: 4,890
Join Date: Mar 2007
Location: minnesnowta
09.25.2012, 09:44 PM

tape those wheels Ballooning wheels have huge centrifugal force and lift the front end right up, causing wheelies.


_______________________________________

It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.
   
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



RC Monster




Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
vBulletin Skin developed by: vBStyles.com