Results 1 to 11 of 11
  1. #1
    RC Champion
    Join Date
    Feb 2009
    Location
    Sydney
    Posts
    1,683

    Improving handling

    Quote Originally Posted by ChrisG23 View Post
    I think this is the next step, revo spec slipper. I think it is necessary to try and make the car a bit more stable at speed before we really push the top end up further. I think shocks are the next step with that. There is no droop in the current setup, so as soon as the car gets light, the tires are off the ground.....
    I thought I'd respond to this post in a seperate thread to preserve the thread it came from........

    Chris, I don't know that droop is a concern. If it's getting 'light', it sounds like aerodynamics is the bigger factor

  2. #2
    RC Turnbuckle Jr.
    Join Date
    Oct 2009
    Location
    Springfield, MO
    Posts
    3,681
    Hmmm I hate encouraging new threads.... but I tend to agree.

    Droop isn't really the issue. In fact at speed the XO-1 will suck down to the ground... it almost seems that what we need is a very progressive suspension setup that moves easily at full extension, and then gets quite firm as the ride height decreases with downforce.

  3. #3
    RC Racer
    Join Date
    Feb 2012
    Posts
    216
    Quote Originally Posted by ducati777 View Post
    Hmmm I hate encouraging new threads.... but I tend to agree.

    Droop isn't really the issue. In fact at speed the XO-1 will suck down to the ground... it almost seems that what we need is a very progressive suspension setup that moves easily at full extension, and then gets quite firm as the ride height decreases with downforce.
    This is exactly what im thinking. On my slash 4x4, the rear springs are like this, very soft at full extension, then stiff under compression. The question is, is there anything keeping the a arm from extending further down, other than the fully extended shock?


    Ps, i already have an email about shocks and springs sent to peterv. I asked him if there are different length gtr shocks. Something longer than the stock xo front, but shorter than the rears.

    What seems increasingly obvious is that the xo will likely become airborne if the car gains a positive AoA at hi speed. So what I im wondering is what effect it will have if we remove the chassis side panels that run from the front tires to the rear. We will lose the NACA duct, but will that make the car more stable at speed, or have an adverse effect.
    Last edited by cooleocool; 03-08-2012 at 02:54 PM. Reason: post merge

  4. #4
    RC Champion
    Join Date
    Feb 2009
    Location
    Sydney
    Posts
    1,683
    What is "AoA"?

  5. #5
    RC Turnbuckle Jr.
    Join Date
    Oct 2009
    Location
    Springfield, MO
    Posts
    3,681
    Angle of Attack....

    he's saying he thinks the nose of the car lifts, gets air under it, and takes flight.

    In my experience, the car sucks down assuming its pointed straight. Get it sliding, and it'll take flight.

    Progressive suspension can be done a couple of ways. On the Slash series it was done mostly in the springs, with the pitch of the coils in the spring vary from end to end...

    But you can do it with shock angle with relation to the a arm as well... you can create a steep angle between the a arm and shock and it will act in a more progressive manner. But we're limited with the XO since there aren't enough mounting options for the top of the shock. The manual discourages changing the lower mount at all.

    (edit) In hindsight thats misleading. If the shock is at a 90 degree angle to the A arm, thats the least progressive setup. When I say a steep angle, I think I really mean a shallow angle, as in the shock and the A arm are closer to parallel.


    As far as longer GTR shocks, you're out of luck.... unless you fit longer rod ends like I mentioned earlier. It can be done, but there isn't any factory options for longer GTRs. As far as I know the Summit setup is the longest GTR's.
    Last edited by ducati777; 03-08-2012 at 12:20 AM.

  6. #6
    RC Racer
    Join Date
    Feb 2012
    Posts
    216
    Sorry, angle of attack. Draw a line down the side of the car, if you raise the nose of the car, the AoA increases. The force of the air blowing on the underside of the chassis causes the car to become airborne. If you reduce the surface area of the underside aerodynamic surfaces, the effects of this will diminish. This is why most other cars of the same basic size dont become airborne like the xo does.

    The aero package works very well when the car is driving along properly, but when you hit a rock or bump and the front lifts, its all over.

  7. #7
    RC Racer
    Join Date
    Dec 2011
    Location
    Clermont, FL.
    Posts
    190
    The car takes flight because of air getting trapped In the body

    Cut the back part out and it's night and day handling at higher speed!!


    Sent from my iPhone 4s using Tapatalk

  8. #8
    RC Turnbuckle Jr.
    Join Date
    Oct 2009
    Location
    Springfield, MO
    Posts
    3,681
    Quote Originally Posted by racksteris View Post
    Cut the back part out and it's night and day handling at higher speed!!
    I hear you man... I cut out the exhaust decal.... not the whole mesh decal like you did. I'm hoping it helps since I've had crap handling lately.

  9. #9
    RC Racer
    Join Date
    Dec 2011
    Location
    Clermont, FL.
    Posts
    190
    Quote Originally Posted by ducati777 View Post
    I hear you man... I cut out the exhaust decal.... not the whole mesh decal like you did. I'm hoping it helps since I've had crap handling lately.


    The car have not try too lift up sine I cut the back out and handle alot better.. its as if the air being trapped in the body from the vent and wheels were holding back the car.

  10. #10
    RC Racer
    Join Date
    Feb 2012
    Posts
    216
    Quote Originally Posted by racksteris View Post
    The car takes flight because of air getting trapped In the body

    Sent from my iPhone 4s using Tapatalk
    I dont think air trapped in the body is the problem. 90% of air is deflected by the surface area of the aero package. The reason the xo takes flight is the same reason it happens to full scale cars at lemans, indy cars etc. The nose pitches up, and its all over. Just like an airplane lifting off a runway. The only way to counter this is to reduce the size of the wing ( underside aero)

  11. #11
    RC Champion
    Join Date
    Feb 2009
    Location
    Sydney
    Posts
    1,683
    Quote Originally Posted by ChrisG23 View Post
    I dont think air trapped in the body is the problem. 90% of air is deflected by the surface area of the aero package. The reason the xo takes flight is the same reason it happens to full scale cars at lemans, indy cars etc. The nose pitches up, and its all over. Just like an airplane lifting off a runway. The only way to counter this is to reduce the size of the wing ( underside aero)
    I'd agree that trapped air isn't 100%. Most if not all the blow over video I've seen have been caused primarily by an imperfect running surface. You can't expect to hit bumps, cracks, stones etc & for it to have no affect. Assuming the front 'high downforce' splitter is installed, it should generate enough negative lift to (or almost) scrape the surface at full throttle. Removing parts of the chassis would most likely have a worsening affect to handling & this would increase expodentially with increasing speed

    Have a read through this thread for some ideas, I posted some pictures to help http://traxxas.com/forums/showthread...-for-Stability...you're striving for a balance of all forces, not just negative lift

    BTW I haven't seen angle of attack written with a lower case 'o' before - so I just wanted to check what you ment

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •