It depends on the event being hosted. At Silverstone for the GP a basic ticket gets you access to the grass/gravel banking around the circuit perimeter, but not into any of the grandstands or seated enclosures.

At the smaller meetings (British GT/F3, VSCC, etc...) you can usually go anywhere you like, even into the pits. I even stood on the pitwall for the first lap of a VSCC race. I doubt I would have been allowed to do this for the GT/F3 though. Actually, I probably wasn't allowed to do it for the VSCC, but nobody stopped me!

The photographers usually have access to the area behind the armco/tyre barriers but in front of the spectator fencing, presumably so they can take pictures without the fence in the foreground.

Quote from The Moose :

There is nothing wrong with weed in moderation.

Yes there is...it's illegal (in many countries). I don't care if it was half a gram or half a kilo, law breakers deserve punishment.

One thing I don't understand is that, apparently, drug consumption isn't illegal in the UK. Possession and dealing are illegal. How, then, do you consume drugs without possessing them?

Quote from Stregone :

Was over at my friend's, playing around with both of our speedlites, doing some off camera lighting. :P

Nice shot, but your friend needs to vacuum more often

Quote from DeadWolfBones :

FOX is really packing in the commercial breaks. 4 in the last 10 minutes or so.

How do you put up with this? Not only do the ad breaks come every 5 minutes or so, the adverts are terrible!

Does everything have to be sponsored? I couldn't believe it when I saw the restarts were 'brought to me' by Claritin! Unbelievable!

We had great weather here last weekend so I took my camera around some of the colleges in the university. I'm particularly pleased with the picture of St John's chapel tower.

I was disappointed not to get any decent shots of my old college but the sun was low in the sky and casting horrible shadows across the courts. I'll have to try again later in the year.

One of the best F1 books I've ever read is 'Chasing the Title' by Nigel Roebuck. Anecdotes from a journalist who's been around for years. Great stuff.

I'll need to have a think about the sloping surfaces part of the question, but I'd like to clarify something about your equation for the lean angle on a flat surface. Is the lean angle defined from the vertical or the horizontal?

Also, whether the angle comes out in radians or degrees has nothing to do with the equation you use, just which mode your calculator is in

Quote from tristancliffe :

Ah, yes, of course. R is the radius, so that's doubled for diameter, which comes out as 2^4 = 16. Where does the 2L come from? Surely the bar can be considered to be held at one end and twisted from the other, thus L is the total bar length, rather than half of it?

The '2' came from the equation for J on that Wiki page. I just added it to the denominator rather than write pi/2 on the numerator.

Quote :

Is the second pi (that forms pi^2) from J = pi(R^4-r^4)?

Yes, that's right. The other comes from the radians -> degrees conversion.

Quote :

This is such elementary (well, A-level) mechanics that I should really know it, but it's surprising how quickly it leaves the brain without more frequent usage!!

Yes! It's been a while since I've used any of this myself! Moments of inertia usually end up confusing me...

Quote :

P.S. I was secretly hoping you'd see this thread Stewart, as you seem to know rather a lot more than me about these things Fancy joining a crappy club racing team as Official Consultant I already offered the position to Bob, but he ignored it! To be fair I was asking him to drive miles and miles to model our car numerically, which is asking a lot to be honest...

Hehe, this is the sort of subject which I really should know something about, but when it comes down to it, I usually realise that I don't I think I might have to pass too, I'm afraid, though I'm usually up for some technical discussion in this forum

Hmm...I'm not sure I agree with your equations.

Using that Wikipedia link...

phi = TL/JG
T/phi = JG/L

T/phi = pi*G*(ro^4-ri^4)/2L

or, in terms of diameters,

T/phi = pi*G*(Do^4-Di^4)/32L

If you want 'phi' in degrees rather than radians,

T/phi = pi^2*G*(Do^4-Di^4)/5760L

Quote from tristancliffe :

Wiki to the rescue, I think

http://en.wikipedia.org/wiki/Torsion_%28mechanics%29

Can that not be rearranged so that

Nm/Rad = (D^4-d^4)RG/L

Where does this 'R' come from?

If you remove it, then the units are Nm. Radians are dimensionless, so the units agree.

Quote :

And therefore Nm/Deg = (180(D^4-d^4)RG) / (L*pi)?
where D=OD, d=ID, R=arm length, G=Modulus of Rigidity, L=length

Actually, no. As the result is in Nm, which is a torque, the arm length shouldn't come into it.

You're forgetting that the conversion factor between radians and degrees has units.

I'll have a proper look through my data books when I get home.

Quote from Jakg :

The Daily Mail is the sort of paper that would have you believe that GCSE's are easy...

Are you claiming they're not?

The results of this survey don't suprise me in the slightest, given my experiences of being on a bus with a crowd of local 6th form students.

Wow. I thought the RA107 looked bad, but this is awful. I wonder if the Renault launch on Thursday will see Renault re-claim the title of 'Worst Paintjob in F1'? Based on today's evidence, I doubt it.

Quote from RMachucaA :

Also, all the people screaming "bloody murder!" are the ones that arent prepared to pay for the experience, granted that experience better be damn good for the money, which judging by papy's previous releases, will be worth it.

I would be more than willing to pay $150 for iRacing (after all, that's only about £5 :razz. The amount of money is not the issue for me.

The lack of a free demo and the subscription payments are what kill it for me and ensure that I will never buy it. When I pay for something, I expect to keep it. I don't want to rent a racing game from them, I want to buy one.

The actual cost is irrelevant to me simply because it's a subscription service. Paying for additional content doesn't bother me either (it's the same as paying £12 to upgrade from S1 to S2), but if I lose the right to play the game as soon as I stop paying, I'm not interested.

OK, one last attempt at this...
Have a look at the circuit map on the Wikipedia page for Istanbul Park:

http://en.wikipedia.org/wiki/Istanbul_Park

Turns 6 and 7 are labelled as seperate corners, whereas the quadruple-apex Turn 8 is a single corner. I can't explain this, but that's apparently the way it is. If I were looking at this picture without prior knowledge, I'd probably label turns 6 and 7 as a single 'turn 6' and label turn 8 as two, three, or even 4 seperate corners, depending on how the mood took me.

Now is it clear why a single, pre-specified track map is preferred to allowing drivers to use their own naming convention? It's nothing to do with the driver not knowing where he is, it's to allow them to communicate very clearly with their engineers what the car is doing in each corner.

Oh, and why is it assumed that the driver will be doing this over the radio? It's perfectly sensible for a driver to describe the car's performance in different corners when he's back in the pits.

Quote from tristancliffe :

Exactly. Listen to radio transmissions and ALL of the drivers know the corner number off by heart at every track. So why have a map.

Perhaps to help them get it right during first practice?

Quote :

You see, we'd established it. Unless of course you are far superior to all F1 drivers and can read maps whilst doing 170mph.

No, I said they'd memorised the corners, not the corner numbers. I obviously misunderstood you.

All I'm trying to do is explain what I heard in a driver interview a few years ago. He said the track map was to help them discuss the performance of the car in different corners. I'm content to believe him, regardless of how stupid it sounds to amateurs.

Quote from tristancliffe :

Do keep up. We've already established that the numbers are memorised by the drivers, because they can't look at the map whilst driving whilst talking on the radio. So why, when they are back in the pits do they suddenly need to rely on a map that 4 minutes ago wasn't needed?

I wasn't under the impression that we'd established that! There's no real need for a driver to remember the corner numbers when he's out on track, is there?

Quote from tristancliffe :

So when do they glance at the map? Because it sure isn't whilst they're driving. So, therefore, if it's already memorised why not remove the map altogether. What, then, is the point?

It just makes it easier for discussion if everyone is using the same corner numbers. The driver knows which corner he is having trouble with and looks up the number on his map. He then tells the engineer that he has problems at corner number X. The engineer looks at his numbered map and can see exactly which corner he's talking about.

For some circuits the corner numbers are obvious, but at other circuits there can be room for different interpretations of what is a 'proper' corner and what is simply a kink. Having a single standardised track map in each team removes any possibilities for confusion.

Quote from Mazz4200 :

Lets hope there's plenty of pic's and vids of them on the net. The one i'd really like to see is the old green and white Fly Saudi livery

With Bin Laden logos!

Quote from tristancliffe :

But that map is hardly useful whilst driving, so to refer to corners means they must have them memorised.

I always thought the map was to show marshall posts in case they need to escape in a hurry, but then I thought "why would they wait for a marshalls post if they need to escape? Just run!".

I can't see why you'd want a map really.

Of course the drivers memorise the corners, but when they're talking to their engineers, having a numbered track map avoids confusion about which corner they're talking about. There's no need to talk about oversteer in the right-hander after the left-kink before the bridge...you can just say 'Turn 5'.

This is how I've heard an F1 driver explain the reason for the track-map. I can't remember who it was though.

Quote from Jakg :

Asked this before, it's so that drivers know specific corner names in case they have an accident iirc.

Also, it's useful to have a track map with numbered corners when drivers are talking to their engineers/mechanics. If everyone is working from the same numbered map, there's no confusion about which corner is which.

Quote from glyphon :

i think the WB was on "sun", but that's not what the image looked like straight off the camera.

first, i opened it in photoshop and cropped it.
next, i added a threshold adjustment layer, and set the slider to where there where only a few points of white pixels remaining and clicked ok. then i switched the color sampler tool* and clicked on one of the white pixels. i then did the same thing for black pixels. and then deleted the threshold adjustment layer.

now that the brightest and darkest points in the image marked, i added a levels adjusment layer, and in the levels screen, selected the highlights eye dropper and clicked the bright point, and then selected the shadows eye dropper and clicked the dark point. clicked ok, and then saved.

it sounds like a lot, but it is really a 2 minute process at the longest.

* eye dropper that leaves registration marks where you click

That's pretty much the same method I used to increase the contrast in my shot, except that I just eyeballed the histogram and set the white point to the highest luminance value in the histogram

I also ditched the red and blue channels from the JPG. The image as-shot was almost perfectly monochrome and the green channel seemed to have more resolution and less noise than the other two (this is probably a result of the RGBG Bayer filter).

Quote from glyphon :

haha...and i though i cropped my shot a lot
seriously though, that's a nice shot of the moon.

and though my focal length a decent bit shorter than yours (300mm equiv), i even had the IS disable for my shot, and think that it turned out well, using the same exposure speed (1/250).

full size crop

Thanks...I probably shouldn't have done the 80% resize now that I think about it. I was expecting the 100% crop to look a bit blurry but it seemed pretty sharp to me.

What white balance did you use for that shot of the moon? My first shot of the moon last night turned out like that because I forgot I'd left the camera set on some crazy custom WB It's quite nice though...I did think of adding some toning to my shot, but I whatever I tried, I kept going back to the B/W version.

Quote from Stregone :

Nice. Still alot of detail in that. Is that lens the 70-300mm USM IS canon lens?

Yes, the non-DO version.

Quote :

I really wanna telephoto, but am leaning more towards the 400mm L prime lens. But it doesn't have IS How do you like that lens? It would be a good halfway stop for me while I save up, hehe.

I've not had much of a chance to use it since Christmas, but I have been pleased with what I have managed to do with it. I'll really see how well it performs next time I take it to Silverstone, which is what it was bought for. The only downside that I can see is that, although it's got USM, it's only a Micro-USM rather than a proper Ring-USM. This means it's not much faster focussing than a standard Micro-Motor drive, and it doesn't have full time manual focus enabled. Oh, and the front element rotates when focussing, so using a polariser is a little frustrating at times.

The 400mm f/5.6L is a really nice lens, but the 70-300 is half the price...it doesn't make sense to me to buy a 'stop-gap' lens for half the price of the one you really want! You could buy the old 75-300 USM (non IS) for less than $200 and be $350 closer to getting the 400mm prime! It's not as sharp at the long end as the much newer 70-300mm, but it might suit you until you get the 400mm.

About IS...it depends on what sort of shooting you'll be doing. If you don't mind carrying a tripod around with you then you don't need IS. If you usually shoot moving objects then you'll probably want to use a shutter speed fast enough to prevent subject motion blur, in which case you probably won't have a problem with camera shake either. However, if you like taking shots of still objects in low-ish light then IS is invaluable. Some of the shots I took last night at 1/160 were a little blurred, but the ones at 1/250 and above were all sharp.

Last edited by StewartFisher, Thu, 17 Jan 2008 13:15.

Quote from Stregone :

Nice Is that cropped? If so, how much?

It's quite heavily cropped. I cropped it to 800 x 600 from the original image (3888 x 2592), then shrank it to 80% (640 x 480) for posting. There was an awful lot of black space in the original!

Quote from Bob Smith :

Regarding more complex aerodynamics, it would be nice for simulating top fuel dragsters and other high speed vehicles but I suspect I would need more data on the aerodynamic shape of the vehicle, which would put it out of the scope of the program. If there any general rules of thumb though, I'm interested. I have noted that it's typically high speed acceleration that is off (specifically, too high) when comparing the outputs to telemetry of the same vehicle.

The only thing I can think of is called the 'Prandtl-Glauert Similarity Rule'. The analysis is, technically, limited to two-dimensional, inviscid, irrotational flows with thin aerofoils at low angles of attack and at Mach numbers well below 1. However, I'm informed that it actually works quite well for real flows.

The idea is that the compressible drag and lift of an aerofoil can be related to the incompressible drag and lift by the following equation:

Cd, compressible = (1 / SQRT(1-M^2)) * Cd, incompressible

where M is the 'free-stream' Mach number (the Mach number of the vehicle, in this case).

You can calculate the Mach number, in air, using the vehicle velocity (v, m/s) and the ambient temperature (T, °C):

M = v / SQRT(401.8 * (T + 273.15))

As I said, a lot of assumptions go into this approximation and there's no guarantee that it'll work for a vehicle simulation. However, it will provide an increase in Cd at higher Mach numbers...this might be enough to reduce the high-speed acceleration. As a guide, the Cd will increase by 5% at M = 0.3 (230 mph) and 10% at M = 0.4 (307 mph).
Or it could just give you complete nonsense

Last edited by StewartFisher, Thu, 17 Jan 2008 01:02.

It's a lovely clear night here this evening so I took my new 70-300mm lens out to take some moon shots. See attached.

ISO 400, f/8, 1/250 sec, 300mm (480mm 35mm equiv.).
Edited in The GIMP to isolate the green channel and bring up the contrast very slightly.

Oh, and this was hand-held...I love IS!