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I sometimes hear that it's safer to drive a car with a more powerful engine, other things being equal, because the extra power gives you the ability to accelera

by kijin 8y ago

I sometimes hear that it's safer to drive a car with a more powerful engine, other things being equal, because the extra power gives you the ability to accelerate out of a dangerous situation. I've always found that argument a little dubious, because very few people have the training to accelerate safely in such a situation. On the ground, it's usually safer to stop a.s.a.p. When you're flying a fixed-wing aircraft, however, it's not an option to stop where you are. So I guess it can be handy to be able to fly away at a high speed and steep angle!

VLM 8y ago
The story comes from towing, where the vehicles are often only stable in tension (if weight is poorly distributed or strange aerodynamic loads) and you can damp the oscillation by hitting the gas on the tow or the electric brakes on the trailer. It you try to stop the oscillation by hitting the brakes on the tow, you'll end up in a horrible accident. The aerodynamic load of a trailer is enough at highway speeds that its like hitting the trailer brakes already if you panic and take your foot off the gas, so if that didn't cause a recovery you're best off flooring it to get the system in tension which usually eliminates sway, then carefully slow down. People who haven't looked into the mechanical engineering of towing are often confused why 400 pounds of stuff in the pickup bed is no problem but 400 pounds of trailer requires strange elaborate sway bars and brake systems and strange dampeners on the hitch... its a oscillation damper not a total power dissipation issue. In theory a perfect aerodynamic and weight balance tow and trailer would never fishtail at any speed; in practice of course they do.
- dsfyu404ed 8y ago
  >400 pounds of trailer requires strange elaborate sway bars and brake systems and strange dampeners on the hitch. You don't need any sway control whatsoever so long as the weight distribution is sane for the speed you want to travel. Look at large boat trailers for examples. They never have sway control unless the owner adds it because they want to load the boat farther back (because their vehicle can't handle the tongue weight). Vehicles not being able to handle the tongue weight of a properly loaded trailer is becoming less of an issue for light loads because asinine CAFE rules force OEMs to push the axles to the very edges of the vehicle increasing wheelbase and reducing rear overhang so your average car or small/midsize SUV today can handle tongue weight a lot better than 15yr ago. >In theory a perfect aerodynamic and weight balance tow and trailer would never fishtail at any speed; in practice of course they do. Only because people are idiots and procrastinate putting the heavy things in the uhaul until the end and then they want to drive 80mph with it. It's not a matter of theory vs reality. There are very few situations where you can't get good weight distribution if you have ten brain cells and ten seconds to plan how you're gonna load stuff.
corint 8y ago
Perhaps overall it's dubious, but I was once overtaking a large lorry on a 2-lane section of motorway, so I was between the central crash barrier and the lorry. As I drew level with the front of the trailer / the back of the tractor, the lorry started to drift into my lane. Braking, I'd have had to avoid all of the trailer, but stamping on the accelerator got me out of his way before the driver realised and corrected to stay in lane. I'm not saying that power is always the solution, but it's handy to have it in some circumstances.
Casseres 8y ago
I think it depends on the driver if they're able to handle the power during routine driving. Here is a 7 second video of Tesla driver accelerating out of what would have been a bad rear-end accident: https://www.youtube.com/watch?v=GRR31NaXoVw https://www.youtube.com/watch?v=GRR31NaXoVw Sidenote: I too have a 2 channel (front and rear) Blackvue dash cam setup. I highly recommend it. It's already paid for itself when it got me back my deductible after someone hit me, whereas without the camera the blame would have been 50/50.
avh02 8y ago
In (less civilized) countries with mountainous roads, I'd take extra power for overtaking since you often move in to the oncoming lane to do so. With a smaller engine you could be stuck behind a truck for 15 minutes. Obviously depends on road conditions, but stronger engine means you need a smaller window to make it.

by kijin 8y ago

VLM 8y ago

The story comes from towing, where the vehicles are often only stable in tension (if weight is poorly distributed or strange aerodynamic loads) and you can damp the oscillation by hitting the gas on the tow or the electric brakes on the trailer. It you try to stop the oscillation by hitting the brakes on the tow, you'll end up in a horrible accident. The aerodynamic load of a trailer is enough at highway speeds that its like hitting the trailer brakes already if you panic and take your foot off the gas, so if that didn't cause a recovery you're best off flooring it to get the system in tension which usually eliminates sway, then carefully slow down. People who haven't looked into the mechanical engineering of towing are often confused why 400 pounds of stuff in the pickup bed is no problem but 400 pounds of trailer requires strange elaborate sway bars and brake systems and strange dampeners on the hitch... its a oscillation damper not a total power dissipation issue. In theory a perfect aerodynamic and weight balance tow and trailer would never fishtail at any speed; in practice of course they do.

dsfyu404ed 8y ago
>400 pounds of trailer requires strange elaborate sway bars and brake systems and strange dampeners on the hitch. You don't need any sway control whatsoever so long as the weight distribution is sane for the speed you want to travel. Look at large boat trailers for examples. They never have sway control unless the owner adds it because they want to load the boat farther back (because their vehicle can't handle the tongue weight). Vehicles not being able to handle the tongue weight of a properly loaded trailer is becoming less of an issue for light loads because asinine CAFE rules force OEMs to push the axles to the very edges of the vehicle increasing wheelbase and reducing rear overhang so your average car or small/midsize SUV today can handle tongue weight a lot better than 15yr ago. >In theory a perfect aerodynamic and weight balance tow and trailer would never fishtail at any speed; in practice of course they do. Only because people are idiots and procrastinate putting the heavy things in the uhaul until the end and then they want to drive 80mph with it. It's not a matter of theory vs reality. There are very few situations where you can't get good weight distribution if you have ten brain cells and ten seconds to plan how you're gonna load stuff.

corint 8y ago

Perhaps overall it's dubious, but I was once overtaking a large lorry on a 2-lane section of motorway, so I was between the central crash barrier and the lorry. As I drew level with the front of the trailer / the back of the tractor, the lorry started to drift into my lane. Braking, I'd have had to avoid all of the trailer, but stamping on the accelerator got me out of his way before the driver realised and corrected to stay in lane. I'm not saying that power is always the solution, but it's handy to have it in some circumstances.

Casseres 8y ago

I think it depends on the driver if they're able to handle the power during routine driving. Here is a 7 second video of Tesla driver accelerating out of what would have been a bad rear-end accident: https://www.youtube.com/watch?v=GRR31NaXoVw https://www.youtube.com/watch?v=GRR31NaXoVw Sidenote: I too have a 2 channel (front and rear) Blackvue dash cam setup. I highly recommend it. It's already paid for itself when it got me back my deductible after someone hit me, whereas without the camera the blame would have been 50/50.

avh02 8y ago

In (less civilized) countries with mountainous roads, I'd take extra power for overtaking since you often move in to the oncoming lane to do so. With a smaller engine you could be stuck behind a truck for 15 minutes. Obviously depends on road conditions, but stronger engine means you need a smaller window to make it.