I have a dumb question.

How come cars never use gyroscopes to fix understeer? If you make a hard right, the gyroscope (weighted) can spin counterclockwise. This is how jets, boats, and certain vehicles turn. Has this ever been attempted in cars? Or does this not work?

 

an interesting proposition. are you proposing to use torque effect to induce a yaw moment in the same direction of turn? seems like an interesting idea, i just wonder how big of a weight and how heavy of a motor would be necessary...

 

understeer in a car is easily enough corrected with driving skill, so i doubt a gyroscopic mechanism would ever be deemed necessary enough to be manufactured..

 

To me, a gyroscope is easier/cheaper than that differential thing in the civic si, which when you make a turn, the outer wheel spins faster than in the inner wheel. This is also the basis of SH-AWD of the acuras

also, the gyroscope can tilt, which helps counter body roll of a car by pulling a car back straight.

Any engineers have any comments?

 

seems like an interesting idea, but dont we as humans already do it naturally when we are under/over steering by just counter steering?

 

Imagine all the gyroscopic forces at work in a car. Heck in a motorcycle those forces are what help you stay upright and stablize. In a car you have obviously the wheels and transmission and engine. Those all produce gyroscopic forces that are noticeable and impressive.
many are either compensated for by differring outputs with regards to the diff or torque, rack n pinion, power steering, and some aid in the performance of the vehicle on their own.
A gyroscope doesnt need a ton of mass if it is spun sufficiently fast enough, or it can have a ton of mass and spun not so warp speed like, either way they need to be significant and massive methinks. And since auto's by and large are designed with weight and compactness the gyroscopic introduction to either nullify or enhance other forces would take away from the previously underlined. Safety as well as energy needed to sustain or introduce the gyroscopic forces imparts a technical strategy that is a bit counter with what the mass market would probably rather have their money go to.
I think it is a lovely concept if applied significantly and efficiently, but I dont believe I have seen it done so yet with regarards to being efficient to cars (dont think about flywheels...diff concept, but some similar principles). Gyroscopic forces are one of the gems in physics but its usually a large undertaking energy wise ...

 

not an engineer, but i know a bit. the awd system sounds like it may be similar to the ones in newer evos that accelerates the outside rear tire in a effort to keep the car from understeering. the dif in the civic si is an LSD. in any turn, with any unlocked dif, the outside wheel spins faster, as it travels a longer distance in the same amount of time.

the fact is, that any amount of force applied would need to be greater than, or equal to the force it is opposing. the force of a car causing it to understeer is a function of what is being required of the steering (front) wheels. generally whe a car understeers, its because of improper braking technique, improper steering technique, or early acceleration out of a corner.

the braking technique to use should be straight line braking in a fwd car. basically, you don't want to still be on the brakes when you turn into the corner. you can try trail braking, but in a fwd you need to be extreamly precise.

the steering should be smooth, with as little correction as possible. when you jerk the wheel into the turn, you are suddenly changing the direction that the wheels are rotating, trying to make them move the car onto that path, and loading up the weight on the outside tire. this increases the amount of grip you are asking from the outside tire, reduces the amount of grip available from the inside tire, and naturally, the car is still trying to go straight, causng that scrubbing understeer.

when you accelerate out of a corner, throttle application needs to smooth. entering the croner, the throttle should be a position to maintain speed, not trying to accelerate, or decelerate. after the apex, you should start applying the throttle to slightly accelerate, moving to full throttle as you wind out the steering wheel. getting to antsy with the throttle will cause the inside wheel to spin faster than the grip available can keep up with (causing wheelspin, and thus understeer).

as far as countering bodyroll, i dont think thats a practical solution. body roll is mostly a problem for the driver, and not the actual car (as far as handling goes). if you counter that body roll, the force applied to cause it will be transferred somewhere else. most likely to the chassis, and into the tires. this is why a lot of miata drivers (track drivers) do not even run a rear sway bar.

the whole idea behind chassis developement, LSD's, suspesion geometry and components, etc; all of it is designed to balance the load to all 4 tires and maximize the grip made available by the tires.

 

Ima add a comment to this. Some FWD cars, when you steer, the back brakes get applied. When rear brakes get applied, they lock a little, causing oversteer, which corrects understeer. This is a safety mechanism because not many people know they're not supposed to break when making a sharp turn.
Vehicle braking apparatus having understeer correction with axle selection - US Patent 6481806
This is also a performance technque. A FWD car can enjoy lack of understeer through this mechanism if it's programmed that way.

Thats why I wanna know why a gyro is unfeasible. People are obviously trying to figure ways to stop understeer (other than teaching driving technique).