2013 FSUK

[Bemo]

Originally posted by Thrainer:
The question now is: Will Formula Student change the rules to influence the balance between concepts?

That's the point which makes it completely nonsense have combustion and electric cars within one class.
It is just not possible to compare the efforts of the teams in a reasoble way. It's almost like comparing boats to airplanes. It just doesn't make sense.

Right now with the FS rules it isn't surprising that two electric cars are in front. E-cars have huge advantages in accel and in efficiency. I don't see any field in which the C-cars have comparable advantages.

I don't like the idea of a competition which is changing rules every year to outbalance performances. In my opinion this is just unsatisfying for everyone involved. It is a great thing, that the electric class exists. But that's what it is - another class...

[Kopito]

I agree and disagree Bemo.

I agree that with the current set of rules, the combustion cars don't stand a chance, because they will be slower in Acceleration and AutoX by default, because they have less power and less torque at low rpm. With the efficiency rules changing this year, and it being rewarding for electrical cars to drive fast again, their advantage in endurance, where they basically were able to compensate for the Economy-loss by just driving fast while electric cars had to drive 10% off their AutoX pace to save energy, is gone as well. The only small advantage thats left is cost, but it's marginal.
So under the current ruleset, I agree. However nobody has explained to me why combustion cars (restricted in the way they are atm) were assumed to be competitive with electrical cars (restricted to 85kW). The only reason this discussion arises now, is because an electrical car was finally able to put it together during an overall event.
Personally I like racing against combustion cars, after all they are racecars, so you should be able to compare them.
But I think if it is supposed to be fair, you have to allow combustion cars, to reach a comparable level of power like electric cars, then things could get interesting again.
If things stay like this, and electrical cars become more reliable (although of the top ten autox cars, the two that actually finished endurance were electric...so I could ask you what that says about the combustion cars, after all these years you'd think the finisher rate would be higher...) I think electrical cars winning the combined competitions will become the rule rather than the exception. We will see what happens in Austria...

[Luniz]

I think I am with Bemo on this issue... artificially balancing the performance of the cars would lead to a very complicated ruleset. Just look at FIA-GT or WTCC Rules... Balance of performance issues, weight penalties and all that, it is very easy to be carried away from what you are actually required to do: Build a racecar!

I think the two will never be consistently comparable, you would have to adjust balance rules every other year and that would make it very inconsistent.

Another thing that I find hard to understand: How can the effort of designing a c- or e-powertrain actually be compared in design judging? I can imagine that this is not an easy task, the requirements are just so different!

[bob.paasch]

I agree with Bemo, I think e-cars and c-cars should be in separate classes.

I don't claim clairvoyance, but in 2011 in the thread "Any way to objectively choose engine" I posted this:

Originally posted by bob.paasch:
The next great leap has already happened: electric drive. Until the rules are changed, I doubt we'll see a combustion car win a combined event like FSUK.

and this:

Originally posted by bob.paasch:
We compete under the existant rules, and with the current rules for fuel efficiency equivalent at FSUK, the electric cars are going to be very hard to beat.

and this:

Originally posted by bob.paasch:
IF GFR goes to FSUK, it will be with an electric car.

At the advisor meeting at FSUK 2011, Jon Hilton announced that they would be combining classes for 2012, but that he wanted both c-cars and e-cars to remain competitive so as to not disadvantage teams with limited resources. I told him after the meeting that the electric cars would dominate his competition. I was wrong in 2012, as both AMZ and DUT failed in endurance, otherwise they would have been 1st and 2nd. In 2013, the e-cars were 1st and 2nd, and had DUT finished endurance the e-cars would have filled the podium.

So this is what we get from the official press release on AMZ's win:

Jon Hilton, chairman of Formula Student, said: "Many congratulations to ETH Zurich on their very well deserved win.

"The electrically powered cars have made huge progress going from being unable to complete the 22Km endurance event to winning overall in just five years. We are delighted by this progress but we will have to see what needs to be done in the future to ensure petrol cars remain competitive."

I expect FSUK will modify their efficiency calculation next year to make the c-cars more competitive.

I also expect it will be extremely difficult for a c-car to win FS Austria this year. That won't stop us from trying, of course.

[Z]

Originally posted by Kopito:
.. with the current set of rules, the combustion cars don't stand a chance, because they will be slower in Acceleration and AutoX by default, because they have less power and less torque at low rpm...

Not considering "Efficiency/Economy" for a moment, I have to disagree with the above comments that C-cars "don't stand a chance" against the E-cars.

Powerwise, the limit for C-cars is about 90kW (see extensive discussions elsewhere), versus the 85kW of E-cars. Granted though, the 85kW is probably a lot easier to achieve on the E-cars...

But, as also much discussed elsewhere, outright power is only a small player in FSAE. For instance, the Acceleration event is primarily won with good grip at launch, not max power at the end of the straight. E-cars are currently winning this because they find it easier to fit 4WD (which has the extra benefit of better energy recovery in braking, which is very much needed to minimise their battery weight). But, as pointed out recently on another thread, a well designed 2WD C-car should be comfortably getting into the mid-3 seconds in Acceleration, and 2.9s are feasible.

With regard to E-cars having better low-down torque, this is simply a matter of the C-car teams getting around to building better transmissions. CVTs have been much discussed, but IVTs are even better, and really not that hard (look under most any modern lawnmower, or better yet, tractors!!!). Forget about ancient sportsbike engines with their sequential "gear"-boxes, and move with the times!

The biggest Dynamic event performance improvements in FSAE will come from a lightweight car with maximum aero downforce. I know you students don't believe this yet, but it should be possible for such a car to go fast enough in Enduro that none (or very few) of the current cars would score any performance points (ie. their times would be ~145+% of brown-go-kart+aero's time). The E-cars biggest disadvantage is their weight, and this works directly against them when aero is added (ie. it is a "first order" disadvantage). They wouldn't stand a chance!

Bottom line is that Electric cars are a dead-end. They are not "the future". They are "the past" (read the history books).

So don't let the Rulemakers fiddling with "Efficiency" formulas dissuade you from following what is rationally the best path...

Z

[Kopito]

Dear Z, I am very sorry because this will come across as rude, but I am stunned by the blatant ignorance at display in your comments.

Originally posted by Z:

Not considering "Efficiency/Economy" for a moment, I have to disagree with the above comments that C-cars "don't stand a chance" against the E-cars.

Z

Zurich would have won without the efficiency (>100points margin to the next combustion, Rennteam Stuttgart, I would say we agree they pretty much know how to build winning FS Cars), even scoring very badly in Acceleration (4.0) for a 4WD e-car (technical problems)

Originally posted by Z:

Powerwise, the limit for C-cars is about 90kW (see extensive discussions elsewhere), versus the 85kW of E-cars. Granted though, the 85kW is probably a lot easier to achieve on the E-cars...

But, as also much discussed elsewhere, outright power is only a small player in FSAE. For instance, the Acceleration event is primarily won with good grip at launch, not max power at the end of the straight. E-cars are currently winning this because they find it easier to fit 4WD (which has the extra benefit of better energy recovery in braking, which is very much needed to minimise their battery weight). But, as pointed out recently on another thread, a well designed 2WD C-car should be comfortably getting into the mid-3 seconds in Acceleration, and 2.9s are feasible.

Z

This is interesting. I am sorry I didnt read that post, but I guess some c-Teams should, because apparently they are all completely incompetent, if it is "comfortably" achievable and nobody has managed in almost 25years this competition exists. We saw Delft (4WD e, 150kg) with a 3.45 on the first accel run at FSG2012 (cold tires), more than 4 tenths faster than the best combustion car that day.

Originally posted by Z:

With regard to E-cars having better low-down torque, this is simply a matter of the C-car teams getting around to building better transmissions. CVTs have been much discussed, but IVTs are even better, and really not that hard (look under most any modern lawnmower, or better yet, tractors!!!). Forget about ancient sportsbike engines with their sequential "gear"-boxes, and move with the times!

Z

Come talk to me again if you have found or built a 180kg FS car (165kg without Aero) that has 350Nm at each of it's four wheels at 0rpm.

Originally posted by Z:

The biggest Dynamic event performance improvements in FSAE will come from a lightweight car with maximum aero downforce. I know you students don't believe this yet, but it should be possible for such a car to go fast enough in Enduro that none (or very few) of the current cars would score any performance points (ie. their times would be ~145+% of brown-go-kart+aero's time). The E-cars biggest disadvantage is their weight, and this works directly against them when aero is added (ie. it is a "first order" disadvantage). They wouldn't stand a chance!

Z

If you have gotten near a laptime or overall points simulation for one event, you will see that its not a easy as more Cz, less kg, and everybody will be happy... I know Monash is destroying everything in Australia, and I personally think they are great guys that build cars that are inspiring, but they will tell you, that the moment electric cars put wings on, they had no chance to win any dynamic event other than skidpad.
I personally believe that a 4WD electric car with a Cz of >3 and enough energy on board to drive an endurance faster than combustion cars can be made <170kg (I am sure we will see it next year).
Look at the event handbooks, and youll see that electric cars, are not one bit heavier than their combustion competition. if you build an ultralight FS Car with lots of downforce, you might get around 150kg this probably using 1-cyl engine, where an electric 4WD car with comparable DF will way around 170kg. Trust me, the electric car will do below 3.5 in accel, probably win skidpad (same DF + 4WD Torque Vectoring..not mentioned to this point), smash the c-car in autoX (much more torque + more traction + same DF + Torque Vectoring + easier to drive). The e-car will be able to coast in endurance and would win overall (efficiency out of the equation..we agree that this adds a further advantage)

Originally posted by Z:

Bottom line is that Electric cars are a dead-end. They are not "the future". They are "the past" (read the history books).

So don't let the Rulemakers fiddling with "Efficiency" formulas dissuade you from following what is rationally the best path...

Z

None of the e-teams want to save the world. None of them are "green". Nobody in FS wants to solve global warming but built the fastest possible car under the current rules. This is not a forum to discuss where the future of mobility lies, this is an FS Forum.
And I am very sorry, but under the current ruleset (even taking efficiency out of the equation, talking purely real dynamics), a well built electric car will smash a well built c-car. I sincerely invite you to come to germany this year to see for yourself (already last year the two best AutoX Times at FSG were posted by a 4WD-non-winged and a 2WD-winged electro, distancing the best c-car by a second (75s-Lap).

[Bemo]

Once more Z is coming around, telling how stupid all people involved in this competition are. Has anyone ever seen anything that guy built? I'm really curious to see these "comfortably" achieved 90kW in a rules-compliant c-car for example...

[Stef de Jong]

Bottom line is that Electric cars are a dead-end. They are not "the future". They are "the past" (read the history books).

Z, really? Might want to consider the operational costs/energy usage and maintainability and add the tremendous performance... Heard anything about a small California car maker named Tesla lately?

[Simon Dingle]

While it's somewhat off-topic, I think Z's probably right on the power front.

I seem to remeber the isentropic mass flow rate of a 20mm restrictor being 73g/s.

Plug in an air-fuel ratio of 0.9 and you get a fuel flow rate of 5.5g/s.

Gasoline has an energy density of 46 MJ/kg. So plug that in and you get a maximum chemical potential energy flow rate (power) of 253kJ/s (253kW).

Now I I'm not saying that this figure is possible. As I'm sure you're all aware ther are all sorts of losses involved in converting that chemical energy to mechanical energy, but 90kW of mechanical energy equates to a thermal efficiency of 35.6%. To give that figure some context it's about the same as that of a current F1 car at full power.

So with the same engine concept as an F1 car, it seems pretty difficult. However, an F1 car gets that kind of efficiency at 18,000rpm, while an FS car would make it at <12,000rpm. Since frictional losses increase exponentially with engine speed an FS car would have an efficiency advantage there. Plus, an FS car can use a turbo to further expand the exhaust gas and therefore has another possible efficiency advantage. The turbo also gets you an added efficiency bonus in that you can choke the restrictor at lower engine speed and make your 90kW where the fritional losses are smaller.

If you're curious as to what's possible in terms of IC engine efficiency, lookup 2-stroke diesel engines as they have an thermal effciency of around 50%.

I'm going to say that I'm confident that 90kW is possible from an FS engine, but maybe isn't easy. I think it would probably involve abandoning the beloved motorbike engines and going for a different concept.

EDITTED for a typo that meant I accidently said 250kW from an FS engie is possible :P

[Simon Dingle]

ps hopefully I haven't made any numerical mistakes, but please let me know if I have