General Questions

[Sharky.]

Is there any advantage to having subsonic ICBMs over supersonic types?

Less noise?

Why would you want subsonic ICBMs anyway? If you have an ICBM capable of Mach 10 bazillion (read: lots), surely a bit more noise doesn't matter as the target'll be hit by it before they hear it

 

[Duke]

Increase in tire circumference? So, the heat from running 400m quickly actually increases the rear tire size?

Actually, it's the centripetal acceleration of the rotating tire that does it. Also, they are designed to. That's why they are all wrinkled at the bottom when the cars are staging - they run very low air pressure and the sidewalls are designed with massive flex, in order to improve bite at launch. Youtube search a few Top Fuel drag runs and watch the rear tires stand up and get taller at launch.

Is there any advantage to having subsonic ICBMs over supersonic types?

Supersonic makes it easier to go low-orbital, and it gets the package there faster. Of course, cruise missles (subsonic) theoretically get the package there undetected, which is their advantage. ICBMS are fussy and maintenance-intensive, too, I suppose.

 

[Metar]

Actually, it's the centripetal acceleration of the rotating tire that does it. Also, they are designed to. That's why they are all wrinkled at the bottom when the cars are staging - they run very low air pressure and the sidewalls are designed with massive flex, in order to improve bite at launch. Youtube search a few Top Fuel drag runs and watch the rear tires stand up and get taller at launch.

So essentially, the sidewalls are designed weak enough to be expanded only by the centripetal force?

 

[Sureboss]

Individual firing cylinders, too. 👍

 

[Duke]

So essentially, the sidewalls are designed weak enough to be expanded only by the centripetal force?

Yes. The tire technology has improved, so they don't jump right up like they used to, but they expand in height by at least 50% of the sidewall height, if not 100%. That video is the one I was thinking of. You can see how those tires are absolutely clawing for traction. Bear in mind that the launch area paving is about as sticky as Post-It adhesive, and the tires feel like bubble gum.

Individual firing cylinders, too. 👍

Thanks, Sureshot. That's one of the videos of which I was thinking. Here's an older example from 1976:



Start about 30-40 seconds in and watch them heating the tires. You'll see how tall they stand up from the speed of their own spinning.

 

[daan]

Is there any advantage to having subsonic ICBMs over supersonic types?

Less pollution. If you're going to blow things up, at least do it in an environmentally friendly way. 👍

 

[Sureboss]

To think, they've gained over another 100mph since then. The bikes are probably doing that now, think Top Fuel bike can hit 225.

 

[Metar]

Individual firing cylinders, too. 👍

I wonder though, why the "Big Bang" concept doesn't work for dragsters. Considering MotoGP engines run that way for improved traction, it made me wonder...

Theoretically, firing the cylinders in groups gives the tyres extra "rest" between each burst of power... But then again, with these amounts of grip and power, it may be a different story.

Yes. The tire technology has improved, so they don't jump right up like they used to, but they expand in height by at least 50% of the sidewall height, if not 100%. That video is the one I was thinking of. You can see how those tires are absolutely clawing for traction. Bear in mind that the launch area paving is about as sticky as Post-It adhesive, and the tires feel like bubble gum.

Yes, the car just before 50s (in Sureshot's video) shows it very well. Incredible stuff - really shows that every kind of motorsport has it's own special quirks and bizarre setups. F1's ultra-stiff suspensions and using tyres as suspensions, compared to twisting sidewalls on dragsters, or the forward-through-friction in tractor-pulling - I think the latter moves the weight forward by simply spinning the tyres as fast as possible?

Start about 30-40 seconds in and watch them heating the tires. You'll see how tall they stand up from the speed of their own spinning.

The car at 40s literally jumped into the air when the tyres expanded.

Though, what was that liquid they flushed in front of it?

 

[Sureboss]

That'll be a traction compound of sorts.

What's this Big Bang theory (relating to motorsport)? Not heard of that.

 

[superberkut]

Though, what was that liquid they flushed in front of it?

I am sure that it is water to increase the friction of the tire to the road, or to prevent it from overheating and exploding.
How does a brass instrument mute work?

 

[TB]

I am sure that it is water to increase the friction of the tire to the road

Water + Asphalt ≠ traction.

Water + Asphalt = Oily = slippery.

 

[Metar]

That'll be a traction compound of sorts.

What's this Big Bang theory (relating to motorsport)? Not heard of that.

Only heard on it last month in a discussion on F1Technical. Apparently, by firing a couple of cylinders in groups, power comes in "bursts", giving the tyres a slightly longer time to rest. Apparently, this gives improved traction, and is widely used in MotoGP (also the reason why 4-strokes get better traction than 2-stroke engines - a longer "break"). In Formula 1 teams probably opted for regular engines because traction-control was advanced enough to counter it anyway, or because of the increase in shock and vibration to the chassis and gearbox caused by this firing-sequence.

 

[superberkut]

Water + Asphalt ≠ traction.

Water + Asphalt = Oily = slippery.

Then why would that same principle not work for basketball shoes? Or is it the method of the force applied?

I guess it is for the tire temperature, if anything, then.

 

[wfooshee]

Though, what was that liquid they flushed in front of it?

Bleach. But I'm not sure I understand why.

Just to put dragster speed into perspective, consider:

The current record ET for NHRA Top Fuel is 4.420 seconds. That's an average speed of 203.62 miles per hour.

Average.

From a standing start.

If you had a straightaway long enough, a race car (F1, NASCAR, whoever) could approach the parked dragster at 200 mph, and the dragster would release the instant the race car crossed the start line. The dragster would be at the finish line first, by less than a tenth of a second, and be doing about 120 to 130 mph higher speed!

 

[niky]

Water+Asphalt=Slippery

IF Water+Hot Tire=Steam THEN =/= Slippery AND Tire =/= Overheat.

 

[PeterJB]

How does a brass instrument mute work?

The mute is inserted into the bell of the instrument, and simply blocks out most of the sound, the amount varies depending on the shape of the mute.

 

[Sureboss]

Only heard on it last month in a discussion on F1Technical. Apparently, by firing a couple of cylinders in groups, power comes in "bursts", giving the tyres a slightly longer time to rest. Apparently, this gives improved traction, and is widely used in MotoGP (also the reason why 4-strokes get better traction than 2-stroke engines - a longer "break"). In Formula 1 teams probably opted for regular engines because traction-control was advanced enough to counter it anyway, or because of the increase in shock and vibration to the chassis and gearbox caused by this firing-sequence.

Remember that Drag racing is all about acceleration though, it's over in 4 seconds. MotoGP lasts 40 minutes (ish), F1 1hr30. Different fuel too, Nitromethane is much more explosive than F1/MOtoGp fuel, maybe that influences it. I doubt you'd want power in bursts, but maybe with 8,000hp power in bursts is a bit pointless.

 

[Metar]

Remember that Drag racing is all about acceleration though, it's over in 4 seconds. MotoGP lasts 40 minutes (ish), F1 1hr30. Different fuel too, Nitromethane is much more explosive than F1/MOtoGp fuel, maybe that influences it. I doubt you'd want power in bursts, but maybe with 8,000hp power in bursts is a bit pointless.

I meant an advantage over a single straight run of acceleration, but indeed having double the power in shorter bursts sounds quite pointless...

 

[Sureboss]

I wonder what a 500ci V8 top fueller would be like if it were a 2-stroke?

 

[PeterJB]

I wonder what a 500ci V8 top fueller would be like if it were a 2-stroke?

Acceleration would be considerabley slower, thats for sure!

 

[ROAD_DOGG33J]

For my Info & Decision Sciences class I have to write an essay. The description is as follows:

Identify and describe a current social problem of your choice (global, national, or local). Describe how one or more of the latest (or currently developing) information technologies could be deployed to help solve the problem. In addition, describe an alliance with one or more industries that could be key strategic players in the technology deployment, and describe how those industry players could benefit from making such a contribution.

My professor mentioned I believe it was providing cheap basic medicine to countries where they don't have access to basic medicine. I think I'm going to do that, unless somebody has an idea that would work better? Any other help is also appreciated.

 

[superberkut]

Maybe building new homes or sewage plants- wait a minute.

Your topic is fine, and indeed a very controversial subject. Best of luck.

And, a 500ci 2-stroke engine would also be very erratic and may break easily. It would also be less clean-burning (not that it is to start, of course...).

 

[TopHat]

Ok, time to ask a question:


I've successfully installed Ubuntu Hardy Heron on my laptop, and I'm not able to access my wireless network. Here's an illustration:

Any ideas as to why it's giving me fits?

 

[Philly]

That's interesting. I would think that the wireless light would be a thing the computer does when you flip the switch and independent of the OS you are running. Have you checked to see if you can access your wireless network in the network menu in the upper right? I just switched over to a wireless network just fine to post this.

 

[TopHat]

I looked on the Ubuntu community forums, and I found out that the Broadcom wireless card doesn't play well with Hardy Heron, so I guess I'm SOL.

 

[Metar]

And my VIA Integrated GPU is only partially supported by Linux, so that's a drag too - not that it has any games in the first place.

I need to re-install Hardy - some of my settings from 7.10 borked during the update.

 

[Sharky.]

I found out that the Broadcom wireless card doesn't play well with Hardy Heron

Install a different version of Ubuntu then

 

[Philly]

Or you could go find a whole different version of Linux.

 

[superberkut]

Do phone numbers follow any specific order in assignment?

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

I had no idea. Thank you.

 

[Sage]

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