Solar Freaks

Hello all,

If anyone didn't already know, Sunsprint 2010 is on tomorrow and Saturday. The weather forecast for Sydney doesn't look fantastic over the next few days and so it will be interesting to see if anyone goes the way of no electronics for any races.

To those taking part, let us know how everything goes.

miseli

How was today's Sunsprint seeding? Was the weather as bad as the forecast suggested it would be?

Hi Marc,

Me and Ben are doing the seeding now using your excel seeding curve.
Its going ok, but we had heaps of DNF today due to poor weather, and many of the races were at 10% light levels.

Moorebank managed to get 24.09s in 12% sunlight . Using you spreadsheet, this results in a -1s predicted lap time in 100% sun . The person incharge of the light readings was not taking averages here, so i have a feeling that's where the error is. Anyways, we are manually adjusting were appropriate.

Ill post some day 1 pics soon.

Just finished the seeding.
Thanks for sending me the excel file Marc, helped heaps.

Tony,

No problems about the excel file. Hopefully I'll be able to use the low sunlight data from your event to make the seeding formula a lot more accurate in the very low sunlights.

As good as it might seem, 24.09s in 12% sunlight is not possible with the current ballasting formula. There must certainly be an error there. Maybe it was an entry error? 24.09s in 22% sounds a little more plausible, although it is still very quick. Perhaps 34.09s in 12% sun? Maybe it was an averaging issue like you mentioned.

As I may have mentioned before, the seeding formula really breaks down and loses any real accuracy from about 20% - 30% downwards. This is because I've never really had any data from any "very good" cars at those low sunlights to work with. The current formula is just a hyperbola for simplicity and is based on a 16s lap at 100%, but I think that something a little more complex will probably be needed to get the shape right from 20% sun and down.

Last year at the nationals, Moorebank easily beat the seeding formula in about 10% sunlight and so maybe I should have taken these times into account before sending you the excel file. Moorebank only ran at the one sunlight though and so I was hoping to get a few more bits of data before making any definite changes to the formula. Cars are also lighter this year than what they were in 2009.

Given that you've got such overcast conditions over there, data from this year's Sunsprint (seeding and competition) would therefore be invaluable as long as an average sunlevel throughout a race is taken. Maybe you can ensure that this is done for tomorrow.

Even if the seeding line follows the performance of an exceptional car, the formula is still likely to break down since a lot of cars do well in the good sunlights but then drop off significantly as the sun % drops off.

I look forward to seeing some pics and race times.

Did anyone try going without electronics?

Marc

Ben and I will be personally collecting the data tomorrow, using the averaging feature on the Nanometer.
Ill try make sure all the light readings/race times are accurate to the best of my ability and send you them so you can fine-tune your curve.

Thanks Tony.

What cell is the Nanometer using to base sun % readings on? Is it one that Ian sent you? If so then it should be fairly consistent with Ian's sunlight meter from a calibration point of view.

Any chance of posting up today's results?

Marc

I am using using a calibrated module i received from Ian for the light meter, and also to calibrate my light box. So i think there shouldn't be too much difference, maybe +/- 3% max between the Vic box.

Moorebank High came first today, posting the fastest time of the day.
Then All Saints Grammar and St Paul's followed.

TonyB wrote:I am using using a calibrated module i received from Ian for the light meter, and also to calibrate my light box. So i think there shouldn't be too much difference, maybe +/- 3% max between the Vic box.

Oh good.

Did anyone try going without electronics?

Conditions were definitely worse than yesterday. We didnt see more than 14% sunlight all day, it was raining and very wet, and some of the finals were run in 4% light.

We have all the car data, times, and light readings, and Ben will post them as soon as he finishes tidying them up.

Results are:
1st Place: Moorebank High
2nd Place: St Pauls
3rd Place: All saints Grammar
4th Place: Newington High

Congratulations to all the above mentioned teams.

Moorebank High were extremely fast for the given light conditions. They were well and truly ahead of the pack. After scrutinizing their car twice, i have concluded that the exceptional performance was due to the extremely great attention to detail in the car. Every Bearing ran so free, every wheel was balanced and ran so true, the car was balanced, the gearing was correct, and meshed perfectly. Derrie and Sunni have put a huge effort into their car this year, and it was a well deserved win. I think they will be very competitive at the national this year.

The All Saints team that came in third ran without a maximiser. The car showed great performance throughout the entire day, but failed to make it up the hill in under 8-9% sun.

St Pauls had great consistency, and was even finishing laps in 4% sunlight. Well done. I think the finals could of even been closer if St Pauls had the gearing right. Personally, i think they geared too low for 11% light.

More details to come...

Here is all the times from today, we just input it directly into your spreadsheet Marc. Also the sunlight is accurate, so this should really help out with the curve. Although, it becomes hard to differ between cars, as if you compare Aether (Moorebank) to Shift (St Pauls), the times for Shift were not too far out for some races, but Aether had a predicted time as -13 seconds. I would say Aether is capable of 16.0 and Shift maybe 17?

I also have yesterdays readings, however the light reading was not taken properly, so I don't really think you can rely on them. If you want them let me know and I will put them up.

I will soon post information regarding scrutineering once I put it all into a spreadsheet.

Ben

Thank you Tony for the compliments, what else can i say?
Personally, i thought the Moorebank girl's car was definitely top 3-4. Pity they had to race against us, but i guess we can't have a total monopolisation of the competition with 1 school.

Well done to all those who competed and won awards.

Ben,

There is a slight mistake in your data entry attachment in race 41, you've got the data the wrong way round. Apart from that, everything should be good.

Thanks Ben. Just the kind of data that I have been after for quite a while now.

Just had a quick look at the spread sheet and the times in final race (race 41) are meant to be the other way around aren't they?

Anyway, yes, please do stick up the results from yesterday as well if you can. They will be interesting even if the sunlight percentages can't be relied on.

I don't think one can really predict how most of these cars would have performed in good sun based on what times they were doing in such bad weather. Because car set ups are different and losses are so much more apparent in such conditions, many cars seriously drop off in quality even though they would otherwise be doing half decently in good sunlight.
Yes, around 16s in 100% sun is about what the top cars should be getting. In fact, they should be going under. The 2009 test car that I gave a run in Melbourne last year completed a 16.43s lap in 79.5% sun and this gives a projected time of close to 15.5s in 100%. Ok this was without an egg and probably had better aerodynamics than what this year's cars will have, but the new 2010 ballasting formula means that less weight is being carried.
I think the difference between the top few cars would have been very little in full sunlight and I would expect both Aether and Shift to have been around 16s.

At the very low sunlights every little bit counts. Something as simple as removing a tyre from the drive wheel could have made a several second difference. As Tony has mentioned, Moorebank's attention to every little detail was the difference between them and the rest.

Marc

Were those using electronics all using the Easymax III? Or did anyone get the convenience of the Automax?

At sunlights that low teams should have been setting their electronics before every race.

Yeah race 41 is the wrong way around. I checked all the others though, and they seem to be correct from the sheet I had with the grid.

Here's Friday's results, again no idea as to the sunlight, so don't take it onto account to much.

Ben

Thanks Ben.

Any chance of seeing some car pics anyone?

Here is the car data, not 100% about the maximisers though, I think there was one more car not running one if anybody is aware. Not everything was recorded as it should have been

Some very interesting figures there.

Like last year at the nationals, the winning Moorebank car's chassis is again several hundred grams heavier than what the lightest cars are. Also interesting that the chassis weights are exactly the same for 3 of the 4 All Saints cars.

The panel FFs all seem a little low in general.
Was the maximum power voltage of panels recorded? Also, was a note of the panel types (ie Engelec, Scorpio, etc) made? From the powers listed I am guessing that most used the Engelec modules.

Marc

Both Shift from St Pauls and Aether from Moorebank used the Scorpio panels.
Blur used a solarex panel, and stilleto used the 10 x new Engelec modules.

There were many cars using the older DSE cells and other cheaper cells with low FF.
The highest recorded FF was the Scorpio panel on shift.

Oh of course. And there was me wondering what kind of panels Shift and Aether were using.
I momentarily forgot that panels are now being measured using the 100% sun datum to be at AM 1.5 and so the Scorpio panels that were reading around 12W last year should now be reading that bit lower.

So no max power voltages were recorded then?