Steering Wheel or Yoke Turns Lock-to-LockPosted by ray-holan on October 24, 2021 at 8:05 am
I know the Aptera suspension is a work in progress and that Roush Engineering is consulting with Aptera on it. Anyone know what is the current or the target turns lock-to-lock figure?
I’m not a big fan of the yoke design, but if the steering geometry is set up with something like <3 turns lock-to-lock (i.e. “quick” steering ratio) then I think I can live with it. That would mean I won’t have to do the hand over hand maneuver more than once to go from all the way left to all the way right — easy with a circular steering wheel, awkward with a yoke design as has been illustrated in the Aptera videos of the alpha. My worry is that in an emergency (e.g. someone cuts me off or a dog runs out in front of the vehicle) I might get my hands tangled up or miss grabbing one of the uneven surfaces of a yoke type steering wheel.
- 16 Replies
- ModeratorOctober 25, 2021 at 8:56 am
Ray, good question for discussion, but are there really two questions here that have become conflated? Yoke-vs-wheel will dominate any related discussion, but I am interested in learning about lock-to-lock, no matter the “hand interface”. It seems to me that drive-by-wire and torque vectoring could implement steering in a way completely unlike tradition. (ex: speed dependent lock-to-lock) Should it? Unfortunately, Aptera is too small to do proper research, unless someone can find public domain info. BTW, with a clean sheet of paper, and power steering, how is lock-to-lock chosen? Ideas?
- MemberMarch 27, 2022 at 12:46 pm
If the yoke is final design, then turning no more than 90 degrees in either direction would be awesome to achieve full steering. if technically possible. I saw a guy who replaced his round steering wheel with a yoke in a Tesla model 3 and the steering was really horrible:
- MemberMarch 31, 2022 at 9:41 am
Here is autoevolution.com‘s take on Aptera’s decision to go with a yoke… https://www.autoevolution.com/news/aptera-will-have-steering-yoke-just-like-the-tesla-model-s-and-model-x-plaid-185326.html
Not too much new here beyond what’s in Aptera’s March 2022 video update although the author does speculate on the rationale. The article does start with a nice intro: “Aptera has a really nice approach toward being transparent with customers and fans. The company makes regular update videos, and they always reveal interesting aspects of the electric trike. In the March update, Jason Hill shared that Aptera will adopt a half wheel, which people also call a steering yoke.” However, refering to it as an “electric trike” just doesn’t seem quite right, even though it may be literally correct.
- MemberMarch 31, 2022 at 1:43 pm
First paragraph from the article about the yoke:
“Yes, you have already seen them in the Tesla Model S and Model X Plaid. You have also heard how badly the idea was implemented in these cars, keeping the same number of lock-to-lock turns and making these cars very difficult to drive more aggressively. Whether you like it or not, that is what the Aptera will get.”
- MemberMarch 31, 2022 at 1:57 pm
Yoke, they could use a progressive approach so you can make small adjustments at a time. If the steering is fly by wire then the programming would be easier. I would like to see a fixed movement so that the wheels match the position of the steering and not like a joystick on/off motion. So if the steering is 160 degrees off center left or right would be lock to lock on the front steering. Actually this could be done on any electrical steering whether connected to a shaft or fly by wire.
- This reply was modified 1 year, 5 months ago by Vernon Michael Gardner.
- MemberAugust 28, 2022 at 4:29 pm
How many turns lock to lock on a Canam Spyder?
I have never riden one, but I understand they are very maneuverable.
I’m Just saying, weather it’s a wheel, a yoke, or handle bars, engineers can make it work.
- MemberAugust 28, 2022 at 4:50 pm
Well, it’s handlebars, so pretty close to a 1 to 1 ratio.
- MemberSeptember 27, 2022 at 11:40 pm
Going to drive by wire, with less than 3/4 turn lock to lock, will have many advantages and make the steering “wheel” totally obsolete.
- MemberSeptember 28, 2022 at 1:22 pm
David, Aptera employee Nicholas specifically stated that Aptera steering is not drive by wire. It is a mechanical system. They are uncertain if they will be able to do any variable rate steering, TBD. Start at 8:50 in this recent interview video from Fully Charged: https://youtu.be/adB-yszi01U?t=530
- MemberSeptember 29, 2022 at 11:20 pm
IMHO, The purpose of the steering device, Wheel or Yoke, is to:
Turn Left 90 degrees … Right hand should end up Straight Up in center.
Turn Right 90 degrees … Left hand should end up Straight Up in center.
Hand over hand turning should not even be possible to do.
In turning Left, the Right hand controls the turn… 90 deg.
In turning Right, the Left hand controls the turn,,, 90 deg.
- MemberSeptember 30, 2022 at 10:06 am
In this video of Gamma in the wild, you can see the bottom half of the yoke through the windshield. So that leads me to believe that currently, you will have to turn the yoke close to 180 degrees to make a modest 90 degree turn.
Edit: At second look, they driver turned the yoke >180
- MemberSeptember 30, 2022 at 11:32 am
I believe the steering architecture is one of at least three things (The 80%) set in stone at this point that have been discussed a lot on the forum. Verification will come with the delta production ready specs/vehicle. Whatever the yoke requires for turning the vehicle we will accommodate or install an aftermarket replacement when we receive our Aptera.
My Model 3 has a steering wheel so their will be some period of adjustment for me. But, based on my brief experience driving a Model S with a yoke, the accommodation will be relatively easy.
The other two are the width of the front suspension (85 – 88 inches) and the exterior finish, some sort of film, hopefully a durable one!
- MemberMarch 23, 2023 at 12:11 pm
Be interesting to see what we end up with for a steering ratio.
The ideal with a yoke to prevent any hand repositioning would be around between ~5.6:1 which is a around 1 full turn lock to lock. Tesla model s is 14:1 which is 2.3 turns. Given statements by Chris in the fully charged video we can safely expect it to be noticeably tighter than that but given the turning video in gamma we know it isn’t super tight either (which is good to prevent being too twitchy at high speed). Perhaps it will be something in between like 8.4:1 or 1.5 turns meaning you just barely need to reach over for the max turn in parking lots.
Note: The above numbers assume Aptera’s minimum turning radius is comparable to to model s. If it is less or more that would scale the numbers.
- MemberMarch 23, 2023 at 2:15 pm
Curtis, how does your 5.6 ratio relate to degrees of hand travel? “Hand-over-hand” cross travel starts at only 90 degrees of hand travel to the 12 & 6 o’clock positions.
- MemberMarch 23, 2023 at 5:44 pm
Reminder: These numbers are based on the statements, observed videos and assumption of a turning radius comparable to a model s. I doubt this is 100% accurate.
It is 180 degrees from the center to the lock on either side (360 total yoke rotation); This is about the max you could turn a wheel/yoke without moving your hands and even then it would be a little unnatural. Without getting into variable ratios and massive related R&D they would need to try to strike a balance. 8.6:1 would be 270 degrees from center to lock on each side (540 total) and is my prediction/guess given the statements/goals (NOT AN OFFICIAL SPEC). The model s is 440 (about 1.2 turns per side) – 880 total degrees from lock to lock.