centripetal force
 

I've seen a lot about using gravity to boost economy, and I heard about fighter jets flying in circles to gain speed. Are there any hypermiling techniques using tight off ramps to gain free momentum?

My area; Columbus, Ga; has a lot of these off ramps. Are there any preferred techniques?

If your tires aren't squealing in the turns, you're going too slow!(just sayin') ;) Unless the off ramp is downhill, you absolutely WILL NOT gain momentum on it. You would gain MORE momentum on a straight (downhill) off ramp, due to less tire scrub. And if you use your brakes, you've lost any advantage gained by the elevation gradient.
Gravity works to increase momentum. Centripetal acceleration has no effect on momentum, it only changes the direction of the momentum vector.

MPG,
I was thinking as well you may be gaining speed at the wrong place / time since the freeway is usually travelling faster than the streets off ramps feed into.

Peter.

Like Mustang Dave said, with an addition.

Fighter jets flying in circles to gain speed? Argh. Ignore whoever you 'heard' that from. They can gain speed by using gravity (diving) or increasing throttle, but certainly not from turning. That's an awesome way to scrub off speed and slow down!

I notice the same effect with my car. I don't think going out of your way to hit these ramps is going to help you.

There are however some people here who use hilly terrain to get awesome mileage using the techniques outlined in 100+ hypermiling tips at the top of your screen.

The South depends heavily on highways to get from point A to point B. Like I said there are a lot of these connecting one highway to another. And the approach is usually uphill so I hit my glide before the off ramp.

What I am talking about is feeling that pull towards the outside of the curve and wondering if there is a way to harness it, possibly at the tangent (exit). I want to play around with lane position in the off ramp.

Being a motorcyclist, I understand losing tire traction for a myriad of conditions. Also I am wary of the safety considerations because some native southerners, I am from Pennsylvania, are afraid to turn faster than 10mph and a lot of these off ramps are blind turns.

I hope you are not talking about perpetual motion crap.

I believe you are talking about centrifugal force. If I remember correctly, centrifugal force is the outward force while centripetal force is the inward force. These forces are for objects moving about an axis in circular motion. Centrifugal force is also the reason that planets don't fall down to the sun. Gravity pulls down while the speed creates centrifugal force that makes the planets stay up. In the case of the moon, the centrifugal force is the greater of the 2 so the moon is constantly moving away from the earth. Eventually, it will just fly off in to space. Centrifugal force is easily demsontrated by tying an object to a stick using a string and then moving your hand so that the objects revolves around the stick. Unfortunately, I don't know how you would harness this energy in a car. Maybe using some set of counter weights to generates force when you make turns. Seems complicated for the little energy you'd get back.

I'm not, that's to be sure.

Also, it's apparent that I do not posses a physics degree. I was wrestling with centrifugal/centripetal conundrum; I used wikipedia, but alas I still don't get the difference.

What I was wanting to know is if there was a trick to use that outward energy to get higher FE. Due to the unanimous response, I am assuming that there is no such technique. I will, however, experiment with the idea when I get my scan gauge and post results. As I stated previously, the testing will be with lane positioning or how I choose to take the corner, not modification of the vehicle.

Sure, if you're going downhill.

That's rubbish.
Flying a circle will cost you energy - lots of it if it's tight.

Good fighter pilots are masters of the energy game though.
If you could get them off their speed addiction, they'd make excellent hypermilers :p

If possible, start coasting further out, in order to carry a safe speed through the corner of the ramp.

I assume that you might get an increase if you take the outermost path on the exits ramps. This is only if you're coasting though. if you're on the throttle, then the inner most path would be better. Keep it safe though. Staying an extra foot inside the white lines might cost you .001 mpg, but the safety factor is definitely worth it.

Think of it as drifting without the drift part. You're simply changing the direction of your momentum. You're not creating or destroying energy, but simply changing the direction. If you change direction too fast, you'll lose energy to friction while if you change direction too slowly, you'll end up using more energy to go the extra distance.

I'm very interested to see some data about this so when you run some tests, post it on here so everyone knows.

Another thing is that all ramps are different, so this may change from ramp to ramp.

Who knew an exit ramp could be so complicated? :D