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Ask Ray Munday - JConcepts, Reedy, Associated Aussie Support Thread

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Ask Ray Munday - JConcepts, Reedy, Associated Aussie Support Thread

Old 03-04-2018, 08:51 PM
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Originally Posted by Tubbers View Post
Actually - looks like we are running middle hole in rear tower (think this is kit). Maybe thats the problem?
Originally Posted by Tubbers View Post


Kids have been improving, but still getting the feel for things. Castle Hills jumps are now bigger and more carpet, and it's taking it's toll on the cars. 3 rear towers yesterday :-(. All snapped at inner shock hole (we run middle as per your setup). Should we look at bezerk, or the vrp alloy towers ?
Hi mate, great to hear you guys are getting out there and having fun! I don't think the shock position will be making much of a difference. AE made a running change to a thicker rear tower, but for maximum durability you can consider aftermarket parts. The Bezerk parts are very high quality and Paul can tailor parts to your request.


Originally Posted by Maraach View Post
Hi Ray

Another question for you... sorry!

Is there a way to slow down the steer in with the b6d? My son is quite often finding himself turning in too quickly. Ihad a similar problem with my b64d but found it calmed down a lot with the 13 degree caster blocks. Is there something similar for the b6d?
Hi mate, sorry for slow reply. You have a couple of options:
1) turn down the steering epa. Most tracks don't need full lock. I don't recommend going too far as it can develop a bad habit.
2) Smoother steering front tyre - web style front tyres (eg Dirt Web ) steer a lot more smoothly than a rib. You can try a part worn / harder compound tyre as well.
3) Stiffer front spring. This smooths out the steering response.

Hope this helps!

Ray
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Old 03-05-2018, 04:36 AM
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Thanks. I will speak to Paul.

I noticed you sometimes use 3 or 4 gear standups in your setup. Which one be preferable for novices (is not sure about 3 v 4, as I have only heard laydown is tougher to master)?
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Old 03-06-2018, 03:32 AM
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Originally Posted by Tubbers View Post
Thanks. I will speak to Paul.

I noticed you sometimes use 3 or 4 gear standups in your setup. Which one be preferable for novices (is not sure about 3 v 4, as I have only heard laydown is tougher to master)?
Hi mate, in 17.5 id just stay with 3 gear as per kit. 4 gear is good for adding power down stability in mod on a looser track, but doesn't brake as well. Laydown corners much faster for sure, but needs a smooth throttle finger and good tyres to work properly.

Ray
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Old 03-06-2018, 09:21 PM
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I really enjoyed your extremely informative Weight Transfer articles (pg. 89). I really like how you explain the physics in slow motion details, rather than the usual "...get more traction" lines. We need more of the "why" like this.

I was wondering if you could explain the significance of chassis roll, in particular, when is more/less roll better/worse? I see many explanations describing how to get more/less roll (RC, springs, anti-roll bars, etc.), but how do you know if you made your roll too soft, or too stiff? I understand you want to set the relative front/rear stiffness to tweak the amount of front-rear traction depending on your handling, but you can get a front/rear bias with an overall soft, or overall stiff chassis roll value. So, what is most appropriate and when?

I've always leaned towards softer is for more slick tracks, and stiff is for higher grip tracks to decrease/increase the transfer transition time. If that is true, which end are you shooting for in general? Do you go for the softest setting you can get away with, or the stiffest setting you can get away with? Which way would you rather error on?

Lots of questions, but I hope you understand my question well enough.
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Old 03-17-2018, 01:28 AM
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Originally Posted by icecyc1 View Post
I really enjoyed your extremely informative Weight Transfer articles (pg. 89). I really like how you explain the physics in slow motion details, rather than the usual "...get more traction" lines. We need more of the "why" like this.

I was wondering if you could explain the significance of chassis roll, in particular, when is more/less roll better/worse? I see many explanations describing how to get more/less roll (RC, springs, anti-roll bars, etc.), but how do you know if you made your roll too soft, or too stiff? I understand you want to set the relative front/rear stiffness to tweak the amount of front-rear traction depending on your handling, but you can get a front/rear bias with an overall soft, or overall stiff chassis roll value. So, what is most appropriate and when?

I've always leaned towards softer is for more slick tracks, and stiff is for higher grip tracks to decrease/increase the transfer transition time. If that is true, which end are you shooting for in general? Do you go for the softest setting you can get away with, or the stiffest setting you can get away with? Which way would you rather error on?

Lots of questions, but I hope you understand my question well enough.
Hi Scott, great to hear from you and glad you enjoyed the articles. Sorry to take so long to reply!

Its hard to give a 100% hard and fast rule for springs, but generally I find erring to a softer spring is better than being too stiff. Generally you want to go up in spring rate when:
- the car feels like it is hooking in on faster corners - especially if its traction rolling or suddenly spinning out. Often that means its just rolling too far and the tyre is getting too much positive camber as it rolls.
- in high speed corners with bumps if it feels like its traction rolling (often from the chassis moving too far and bottoming)
- if the car feels lazy exiting corners, like you have to wait for it to straighten up before you can get on the power
- If you have a section where you need to get back on power quickly after a jump or if there is a corner after a jump and you need to wait for the car to settle
- If you want the car to jump a little further over a jump

Signs that the car is too stiff:
- It feels like it is skittish / darty and partway through corners loses grip and pushes wide
- It feels locked in then suddenly loses grip halfway through the corner
- Feels skaty in low grip / low speed sections where you feel like you are driving on eggshells and having to be overly smooth or precise
- It skips over bumps rather than absorbing them


Usually for faster/ higher grip tracks I run a stiffer spring and for more slick or low speed tracks I go softer. The tyre has an impact as well - some tyres like slower weight transfer (which you get with a softer spring) while others seem to like a quicker weight transfer and need to stay flatter.

With a 2wd I find its most important to get the weight balance right first, then the spring rate.

Generally if the car is balanced but feels too soft or too stiff I will change both front and rear springs together. With the 4wd I tend to change bars rather than springs once I have found a good balance.

Hope this helps!
Ray
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Old 03-17-2018, 04:35 AM
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hi ray im upgrading from tlr to the 6.1 when its availaible.
im running the sa state titles. just wondering if i should have a stand up trans ready for it. i have no knowledge on the layback.
bear in mind from last year the track is more sweeping and less dusty a fair bit more grip than last year. running holeshots
i didnt really want to spend more money and probably prefer to run the car box stock but not if it means being or the pace by alot always appreciate your help
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Old 03-17-2018, 09:20 AM
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Originally Posted by crusty View Post
hi ray im upgrading from tlr to the 6.1 when its availaible.
im running the sa state titles. just wondering if i should have a stand up trans ready for it. i have no knowledge on the layback.
bear in mind from last year the track is more sweeping and less dusty a fair bit more grip than last year. running holeshots
i didnt really want to spend more money and probably prefer to run the car box stock but not if it means being or the pace by alot always appreciate your help
Hi mate, Im looking forward to going back to Adelaide for the SA titles!

I don't have any B6.1 parts and have not been able to test the layback or new standup but I have been speaking with some of the team drivers in the US who have. Given the higher traction and more flowing layout, the layback may be OK for the track but Id say will probably need the shocks rearwards and the brass C block. What I am really looking forward to trying is the new standup with shocks forward which I think will work well on this sort of track. As soon as I get my parts (which is generally the same time as the public) I will be working as hard as possible with my teammates to try out these variations. Personally I think the new standup will be lower risk.

See you in SA.

Ray
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Old 03-17-2018, 10:18 AM
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Default Mental Performance Video

Hi guys, I've started a video series called 'Science of RC'. Topic 1 is mental performance

Ive uploaded it to my facebook page and ive also written an accompanying article with more detail. See link below.

I hope you enjoy and if you have any questions, ask away!

https://m.facebook.com/story.php?sto...96568894020064
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Old 03-17-2018, 02:42 PM
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Originally Posted by ray_munday View Post
Its hard to give a 100% hard and fast rule for springs, but generally I find erring to a softer spring is better than being too stiff.

Usually for faster/ higher grip tracks I run a stiffer spring and for more slick or low speed tracks I go softer. The tyre has an impact as well - some tyres like slower weight transfer (which you get with a softer spring) while others seem to like a quicker weight transfer and need to stay flatter.

With a 2wd I find its most important to get the weight balance right first, then the spring rate.

Generally if the car is balanced but feels too soft or too stiff I will change both front and rear springs together. With the 4wd I tend to change bars rather than springs once I have found a good balance.

Hope this helps!
Ray
Ray, This was exactly the answer I was looking for, and great descriptions. Thank you.

I also wonder about the role of dampers for weight transfer. You focused mainly on springs, which are obviously important, but does that mean that dampers are relatively insignificant in comparison? I'm assuming the damping can also affect the timing of weight transfer due to slowing the response of the motion, but how does it exactly affect the timing? My understanding assumes that a soft spring slows that weight transfer because it takes longer time to get the full compression of the spring, since it will need to deflect more than a stiff spring to achieve the same steady state spring force. The dampers will also provide a force due to the velocity only, so while they don't affect steady state, they must provide a significant force during the roll. The way I envision it, the dampers sort of share the load, effectively quickly transferring weight initially through the dampers, then as the springs compress, the damper slows and now the springs take the lion's share of the load. So, would a stiff damper effectively more quickly transfer the weight while the springs catch up? How does that load transfer occur? I guess I'm trying to understand the load sharing and timing curves. I believe I saw a graph of that some time ago, and it made some sense, but I can't remember it exactly now.

Would you use the oil to tune load transfer timing? Or, do you mostly use the oil to balance out the damping ratio with the springs you decide to use?

Really looking forward to your series. With your simplified explanatory style, I believe it will be extremely educational and beneficial for all racers.
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Old 04-01-2018, 04:05 AM
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hi ray. thankyou so much for the for the helpful day at arcr this weekend. definitely helped me out alot. just wondering what the chances are of the b6.1d arriving before the state titles in sa? i have pre ordered but i heard there maybe delays.
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Old 04-01-2018, 03:58 PM
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Originally Posted by crusty View Post
hi ray. thankyou so much for the for the helpful day at arcr this weekend. definitely helped me out alot. just wondering what the chances are of the b6.1d arriving before the state titles in sa? i have pre ordered but i heard there maybe delays.
Hi mate glad yiu enjoyed it Im always interested to hear which aspects were most useful / interesting.

I don't know the exact timing of the b6.1d arrival in Aus. Im hoping to get mine this week and i normally receive mine the same time as customers.

Ray
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Old 04-02-2018, 05:23 AM
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Originally Posted by icecyc1 View Post
Ray, This was exactly the answer I was looking for, and great descriptions. Thank you.

I also wonder about the role of dampers for weight transfer. You focused mainly on springs, which are obviously important, but does that mean that dampers are relatively insignificant in comparison? I'm assuming the damping can also affect the timing of weight transfer due to slowing the response of the motion, but how does it exactly affect the timing? My understanding assumes that a soft spring slows that weight transfer because it takes longer time to get the full compression of the spring, since it will need to deflect more than a stiff spring to achieve the same steady state spring force. The dampers will also provide a force due to the velocity only, so while they don't affect steady state, they must provide a significant force during the roll. The way I envision it, the dampers sort of share the load, effectively quickly transferring weight initially through the dampers, then as the springs compress, the damper slows and now the springs take the lion's share of the load. So, would a stiff damper effectively more quickly transfer the weight while the springs catch up? How does that load transfer occur? I guess I'm trying to understand the load sharing and timing curves. I believe I saw a graph of that some time ago, and it made some sense, but I can't remember it exactly now.

Would you use the oil to tune load transfer timing? Or, do you mostly use the oil to balance out the damping ratio with the springs you decide to use?

Really looking forward to your series. With your simplified explanatory style, I believe it will be extremely educational and beneficial for all racers.
Hi Scott, simple but tricky question and i think it will take more pics to answer properly. Definitely a topic i want to cover in a video.

Yes damping has a significant effect in weight transfer and timing. My previous reply was oversimplified!! Basically the order of factors creating load transfer is:
- initial turn in - frt roll centre (rear roll centre force is delayed a little, until the vehicle has started to yaw and the rear slip angle builds)
- vehicle starts to roll - damper force builds up quickly, roll centre force still exists, spring force just starting
- steady state - damper force drops to zero, spring force and roll centre force high

Basically dampers control the rate of buildup to steady state. Firmer dampers basically allow the car to reach steady state more quickly without overshoot. Overly heavy dampers can make the car feel sluggish as they slow the vehicle movement. Too light dampers make it overly reactive and unstable as the car rolls quickly to buuldup spring rate but tends to overshoot.

To correctly understand dynamic weight transfer, i find it best to consider a free body diagram of the car. Steady state weight trabsfer is a function of lateral g, cg height and track width. This weight transfer is resolved by the total weight transfer due to roll centre, damper and spring forces. During dynamic weight transfer, the total weight transfer is less than static while the vehicle is rolling out (roll acceleration outwards), but becomes greater than static as it slows down (roll acceleration inwards) and especially if the body has overshot and is rolling back in to the steady state position. The roll acceleration / roll inertia has a significant effect on dynamic load transfer. Dampers reduce roll velocity (and acceleration) so they work to keep the weight transfer more constant and therfore smooth out the handling response.

The big trade off with dampers is that they also work to control the ride of the vehicle over bumps and jumps and need to work as a package with the springs to do this properly.

Hope this partially answers your question!!


Ray
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Old 04-06-2018, 01:50 AM
  #1393  
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Hi guys,

Ive been sharing some B6.1D build pics on facebook. The album is here if anyone is interested. I am building up a standup version for outdoors.

https://www.facebook.com/media/set/?...1&l=ab90a4fa39
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Old 04-19-2018, 04:53 AM
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Default Rc Preparation Checklist

*RC Maintenance Routine*
Having a maintenance routine is vital to having your cars running consistently at their best. I'd like to share the routine we use between each race, prepping for club days and prepping for big events, so ive created a quick reference chart. Hope you find it useful!

Ive separated into 4 areas:
- when you first get to the track...
- between each race on the day
- prep after club meets (best to do as soon as possible afterwards, dont wait until the day before the next meet!)
- prep for a big event
Make sure you look up the Aussie Builds page by Andrew Selvaggi for tips on how to run in your diffs, set your slipper, set ride heights and bleed shocks as per the schedule below.

Thanks Reece Schaefer for the inspiration for this post!!

#WeAreAE

Attached Files
File Type: pdf
201804 Vehicle Prep Matrix.pdf (305.5 KB, 1680 views)
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Last edited by ray_munday; 04-19-2018 at 05:13 AM.
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Old 04-19-2018, 05:45 AM
  #1395  
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hello!
thanks friend. good job!
i am antonio fron facebook.
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