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daisy · 02-16-2009, 11:30 AM

I want a gauge that shows me velocity squared, what I'll call a parabolic speedometer. I've been kicking around this idea for a while, and I thought I'd bounce this off everyone here.

What good is velocity squared? After all, you can't use it to figure out how much time it takes to get somewhere. However, from a physics standpoint, velocity squared is crucial.

Two important quantities are related not to velocity, but to velocity squared – kinetic energy and aerodynamic drag. From a practical standpoint, this has a couple implications. It means that v², not v, determines how far you will climb up that upcoming hill. It means that v², not v, determines how much aerodynamic drag you'll experience – the predominant velocity-dependent loss. It means that v², not v, determines how bad an accident will be. How fast your v² dial goes up determines your power output, regardless of speed (unlike the current speedometer).

Ok, so maybe there's some dry physics implications behind a v² meter. How will that help me? Well, I can't count the times I've been coasting uphill to a long light, and I've either over- or under-shot it because of *tiny* changes in pulse speed at the bottom. Or going downhill I'll expect to pick up more speed than I do. And does anyone else find it hard to believe that drag at 75 mph is twice that at 53 mph? Even if you believe it, can you picture it? I know I can't.

Numerically, I think v² isn't very interesting. Miles squared per hour squared, anyone? Perhaps you could label it in vertical rise (in feet) by dividing by 14.962. This is probably the best you could get with a ScanGauge. Personally, I'd prefer to have something a little more spatial – a regular dial speedometer, complete with mph marks, that stretches out at higher speeds. I guess you could have a linear scale on the inside that shows rise distance as well.

Once I get my OBD2-USB adapter, I'll work on coding something up (Linux only, most likely).

Thoughts?

02-16-2009, 11:30 AM	#1 (permalink)
daisy EcoModding Lurker Join Date: Feb 2009 Location: upstate NY Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	A Modest Proposal – The Case for a Parabolic Speedometer I want a gauge that shows me velocity squared, what I'll call a parabolic speedometer. I've been kicking around this idea for a while, and I thought I'd bounce this off everyone here. What good is velocity squared? After all, you can't use it to figure out how much time it takes to get somewhere. However, from a physics standpoint, velocity squared is crucial. Two important quantities are related not to velocity, but to velocity squared – kinetic energy and aerodynamic drag. From a practical standpoint, this has a couple implications. It means that v², not v, determines how far you will climb up that upcoming hill. It means that v², not v, determines how much aerodynamic drag you'll experience – the predominant velocity-dependent loss. It means that v², not v, determines how bad an accident will be. How fast your v² dial goes up determines your power output, regardless of speed (unlike the current speedometer). Ok, so maybe there's some dry physics implications behind a v² meter. How will that help me? Well, I can't count the times I've been coasting uphill to a long light, and I've either over- or under-shot it because of tiny changes in pulse speed at the bottom. Or going downhill I'll expect to pick up more speed than I do. And does anyone else find it hard to believe that drag at 75 mph is twice that at 53 mph? Even if you believe it, can you picture it? I know I can't. Numerically, I think v² isn't very interesting. Miles squared per hour squared, anyone? Perhaps you could label it in vertical rise (in feet) by dividing by 14.962. This is probably the best you could get with a ScanGauge. Personally, I'd prefer to have something a little more spatial – a regular dial speedometer, complete with mph marks, that stretches out at higher speeds. I guess you could have a linear scale on the inside that shows rise distance as well. Once I get my OBD2-USB adapter, I'll work on coding something up (Linux only, most likely). Thoughts?