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The bits of UQR-14 "toad" that worry me, is the chassis looks too light, and is ment to be 23kg. (March 16, facebook). But what would I know, it just looks too light, would flex a bit. The other problem is finding cables that are infinitely stiff in tension. I feel there would be as much spring in the cable as there would be in the actual springs. But I'm sure they have it figured out as Big Bird has been up there.
University of Tasmania (UTAS)
FSAE rules require a minimum 50mm of suspension travel.
Pat Clarke
The trick is... There is no trick
But do you have to demonstrate the 50mm travel by putting 1 tonne on it to make it move?
University of Tasmania (UTAS)
the rules require that the suspension be capable of 50mm of suspension travel, they do not require you to use any of it during the event.Originally Posted by Pat Clarke
'01-'06 Cal Poly Pomona
The UQR design has evolved considerably since those renders. Our design team have been spending many late nights trying to get a design together to meet our deadlines. We have shared bits and pieces along the way, but the final product will be different again. As far as suspension goes it will be mode separated low warp stiffness - just linked differently to what was previously shown. The reason for change is mostly driven by simplicity and availability of springs. The chassis is so light because the vehicle concept allows it to be, this was a major driver of our concept.
As a learning exercise, diving into an unknown concept has taught us more in 3 months than 2 years of iterations. For most of our members the cars competition performance is second to the educational opportunity of developing something from a blank page. That said, we believe it will perform - especially with the weight advantage over a conventional setup. We don't expect to get it right first time (or anytime really), so we are aiming for 4+ months of testing.
To what datum? What reference plane? What suspension mode? Do all wheels need to travel simultaneously?
More specifically, do you think that any FSAE car has 25mm of wheel compression statically?
Mitch Bessell - UQ Racing
Mitch,
Our car has 32mm of wheel compression at static ride height with driver. Just so you know.
For people like you that want to learn there is a specific tool available. Have a look at it : www.dynatune-xl.com . You can learn about how to design a suspension and see what these parameters can do on full vehicle behavior. You can even create your own tire and learn about what makes the tire work.
Cheers,
Dynatune, www.dynatune-xl.com
I think he means static compression from the droop stops, at ride height with driver, not available compression travel to the bump stops.Mitch,
Our car has 32mm of wheel compression at static ride height with driver. Just so you know.
32mm, (or 25mm ) of free droop would produce a ridiculously soft car, and I have never seen one running that soft.
Ironically, the soft twist designs are capable of giving the required 25mm without the low rates if it was ever enforced at scrutineering, but all the conventional cars would be rubbish (or spend a lot of time changing springs to get checked), so that will never happen.
Pete
Some of our cars in recent history ran over 50 mm, close to 60 mm if I remember correctly.
It was done with rising rate rockers so that those cars were not too soft. Of course there is no real reason to have that much droop travel and the rising rate made it a bit harder to tune.
WWU FSAE
2010-2011 Chassis/Welder
2011-2012 Tech Director
2012-2014 Project Manager/Welder
Ah, it doesn't compress 32mm from the weight of the driver and chassis, that's only about 20mm. Admittedly, we do run a very soft car with a big drivers. I can think of one one or two teams that run softer.
SomeOldGuy, I was reading a thesis paper recently which analyzed a suspension system and breaking it down to the basic equations again. The goal was optimization of the system as an electrical circuit with varying amounts of resistance, capacitance, and two different types of inductors (someone may be able to figure out why). It turns out that having a 'helper' spring with high spring rates help tire grip when the primary springs are at high spring rates because it allows the system to deform to the road with disturbing the chassis and causing unwanted load transfer. However, the stiff spring rates allow for proper rate of load transfer during maneuvers that occur in high performance situations so the helper springs are only allowed a few mm of travel. If I can dig it up, I can link it here later.
Kettering University Vehicle Dynamics
Formula SAE 2010 - 2015
Clean Snowmobile Powertrain 2012 - 2015
Boogityland 2015 - Present
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