| HN Mirror

aziaziazi 137 days ago

I'm unsure manufacturer's press kits are to be taken as an honest source of information : the goal of the authors is to make people love a brand, buy a product... but not to educate, share objective information or strategic choices.

zamadatix 136 days ago

Very peculiarly, everyone seems to actually agree the handles are a little more aerodynamic. It's the possibility the manufacturer's teams (except marketing, apparently) could ever have also considered this as one of several benefits when choosing the design which is at such levels of doubt. Moreso, people are willing to dismiss it saying they'd want a certain type of source instead rather than just seeing whether that kind of source does also agree.

To complete the loop on the latter: Tesla's 2012 handle patent https://patents.google.com/patent/US9103143B2/en

> Conventional door handle designs typically have less than desirable aerodynamics due to protrusion of the exterior door handle from the surface of the door and the recessed area over which it spans. As the vehicle moves, these conventional door handles interrupt the smooth surface of the door and thereby increase the overall drag of the vehicle. Depending on the size, depth, and overall shape of the recessed area, for example, the corresponding area under the door handle further contributes to reduced aerodynamics of the vehicle. Designers have not focused on improving aerodynamics in this area as the exterior door handle seems relatively small and inconsequential.

> 104 in the retracted position provides both a smooth appearance and advantageous aerodynamic qualities when the vehicle is in motion

I'm starting to wonder if an interview with David Wheeler (what a name for a car patent) et al would even be believed here at this point.

AlotOfReading 136 days ago

If you read this thread, no one has claimed flush handles aren't more aerodynamic. What was claimed is that the aerodynamic benefits are negligible and as a result, that's not actually a serious consideration in choosing them.

Even the aero study done by range rover doesn't claim they're a meaningful improvement. It claims the handles came from the product design vision first.

> Depending on the size, depth, and overall shape of the recessed area, for example, the corresponding area under the door handle further contributes to reduced aerodynamics of the vehicle. Designers have not focused on improving aerodynamics in this area as the exterior door handle seems relatively small and inconsequential.

Aerodynamics is complicated. You should measure the actual impact rather than guess. "just make it smooth" is a rule of thumb, not a law. If we're following rules of thumb, my copy of Theory and Applications of Aerodynamics for Ground Vehicles specifically says this on the subject:

    The door handle does not need to be flush with the car body to be aerodynamically beneficial; it only needs to blend with the car body in the same way that the posts blend with the side glass.

This is after the section where it recommends flush, airplane style handles as optimal, because again the original claim is that the magnitude of the improvement is negligible.

zamadatix 135 days ago

> If you read this thread, no one has claimed flush handles aren't more aerodynamic. What was claimed is that the aerodynamic benefits are negligible and as a result, that's not actually a serious consideration in choosing them.

I'm not sure how this differs from when I had previously started "Very peculiarly, everyone seems to actually agree the handles are a little more aerodynamic. It's the possibility the manufacturer's teams (except marketing, apparently) could ever have also considered this as one of several benefits when choosing the design which is at such levels of doubt".

Regardless, I continue to find myself in complete agreement w.r.t. this.

> Even the aero study done by range rover doesn't claim they're a meaningful improvement. It claims the handles came from the product design vision first.

My argument remains flush handles in the automotive industry are about more than just one thing alone (more specifically, that drag is indeed also one of those things). Hence I find myself rather lost as to how lack of being the first reason for Range Rover should strike drag as having already been shown as one of their other listed reasons. As far as I can conceive, being about more than one thing alone inherently necessitates some of those reasons are not always to be given as a first reason. Similarly, I don't follow why only the first reason might be held as non-negligible.

> Aerodynamics is complicated. You should measure the actual impact rather than guess. "just make it smooth" is a rule of thumb, not a law.

Other engineers in the field are well aware aerodynamics is a fickle beast and they are not commonly guessing their vehicle aerodynamics by rule of thumb, as you already seem to be very familiar with based on mentioning the Range Rover aero study. Of course, I don't like to leave such a claim uncited or unsourced (regardless how familiar it seems to all already) so here is an SAE paper backing claims Tesla did indeed extensively test the aerodynamics of every external component (for the same vehicle the patent is referring to) rather than guess the impact of exterior elements by rule of thumb https://www.researchgate.net/profile/Robert-Palin/publicatio...:

"Aerodynamic optimization is a major contributor to the overall efficiency of an electric vehicle and the close integration of the Design and Engineering groups at Tesla Motors was specifically arranged to process design iterations quickly and enable the fully informed development of the exterior surfaces at a very rapid pace... Following aerodynamic optimization at the overall shape level, focus switched to optimization of production parts, and every external component of the Model S has been examined in great detail searching for aerodynamic performance, since areas that may seem insignificant in isolation can rapidly accumulate to have a substantial impact on the whole."

> If we're following rules of thumb, my copy of Theory and Applications of Aerodynamics for Ground Vehicles specifically says this on the subject...

We're not just following rule of thumb, but everything in the comments prior still appears to align with this passage anyways. One indeed does not need to make the door handle optimally flush to make a design choice which is aerodynamically beneficial. Clearly, however, the additional possible efficiency is not completely negligible (or an ignored factor) in flush door handle design consideration by many manufacturers in order to make exclusive way for reasons other than drag. One does not even need to conclude this from any of the evidence, to repeat the relevant portion of the prior citation instead:

"Following aerodynamic optimization at the overall shape level, focus switched to optimization of production parts, and every external component of the Model S has been examined in great detail searching for aerodynamic performance, since areas that may seem insignificant in isolation can rapidly accumulate to have a substantial impact on the whole."

Again, I'm not trying to argue drag is the only reason (or even that it's the primary reason). Just that claims the additional drag is negligible or saying that flush handles aren't about drag does not redefine what the auto makers themselves say about drag being a reason.

They're not, but range rover actually published an aerodynamic study in SAE mobilus recently. They mention the door handles as part of the product design vision and offhandedly mention it's one of multiple changes that help ensure the flows coming off the front arches don't break up as they move down. They don't bother to single it out though, or even give numbers for the effect of the group (unlike more significant improvements).

acdha 135 days ago

They’re also selling a massive vehicle which was designed for macho aesthetics rather than performance. Bragging about minor aerodynamic tweaks is how they convince buyers that it’s okay to spend even more money to take the edge off of that fashion decision. It’s like the places which brag about their single use plastic using some recycled material because they don’t want to say it’d be even better if you bought something which could be reused many times instead.

PearlRiver 137 days ago

Exactly it is not science but purely cosmetic. Which for some reason makes HN mad but guess what people choose cars based on how they look and how they are marketed! There has never been a rational man. Spock is not real.

All of the things you mention are considerations that every automaker considers. Product design engineering is simply an exercise in weighting those factors, among many others.

I'm saying flush handles aren't about drag, not passing judgement on whether those other factors are bad.

Drag is absolutely one of those factors. Yes, it only contributes a small amount to the overall drag profile of the vehicle, but a vehicle is a sum of its parts ultimately.

It's not a meaningful factor in decisionmaking. Manufacturers went on an aerodynamics optimization spree in the 80s after the fuel crisis. Concepts like the Ford Probe actually dropped handles and all other protruding surfaces in favor of things like electrical touch panels. Seriously, go look at the photos. Even the pillars are flush.

The production vehicles designed after these concepts often used flush pull-up handles for aerodynamics. Those handles later disappeared in favor of the more reliable pull-bar handles we're familiar with because improved CFD made it clear how minimal their benefit actually was for the tradeoffs.

Of course, even if we accept that all the mechanical complexity of flush handles is necessary for aerodynamic reasons, it's not the only alternative to pull-bars. Look at the Volvo EX60 for an example. Designing a flush handle is hard. Tesla spent years working on it. It's not something undertaken for negligible aerodynamic benefits.

I'm not at all suggesting the primary factor for the change was made for aerodynamic benefits. I am saying that the entire concept is a nod to aerodynamics. That's where the idea conceptually originates from, and it helps more than zero.

Similar to how Mazda has bragged about shaving grams off of a rear view mirror in a Miata. Are Miata's light because their rear view mirror lost a few grams of weight? No. Are Miatas light because Mazda applied that design philosophy to the whole vehicle? Yes.

jjtheblunt 137 days ago

What tradeoff is there between pull-up and pull-out handles?

They can't take as much force and they're less reliable. Sometime in the 90s-ish a new test came into force that greatly increased the impact they had to take without unlatching and continue working. The pull bars made it easier to meet because they're secured on both sides.

The pull-up latches also caused issues for people with long nails. In some places spiders liked to nest inside them. Places with snow had issues with a sheet of ice forming over the entire panel, an issue that also occurs with modern flush latches.

seanmcdirmid 137 days ago

> Flush handles exist as brand differentiators. They're a "futuristic" feel-good feature that consumers want, like engine noise, tablets, and colorful dashboards.

Incorrect. They are most definitely there to save money on production and development costs, like all the other stuff you misattribute to brand differentiators. Consumers like lower prices, car companies like more profit. Yes, it looks fancy, but it is cheaper to produce, judt like the tablet dash.

Literally none of those are cost savings. Touchscreens are, relative to buttons, but not relative to small touchscreens (what I was actually comparing to).

I'm not sure a flush handle is actually cheaper either. The only real difference is the metal bits that connect to the latch assembly. One goes to the interior lever, one to the exterior, and one has the lock pin.

A cost-optimized flush handle gets rid of those in exchange for a motor/encoder unit. The expensive parts of the latch mechanism remain basically identical since it has to be a giant chunk of metal for safety reasons. Maybe the handle differences make up for it, but I'd want to see numbers given that it's made its way onto high end cars first.

seanmcdirmid 136 days ago

No, really, think about it. A touch screen is literally one component plus a computer you need anyways. Buttons need scaffolding, they need to be wired, etc. If you are designing a new car today, figuring out where all those buttons go for each model is a chore, it makes production more complicated, it requires more logistics vs just a touch screen.

Flush handles have to do with creating a recess in the body for normal handles. It’s just easier to cut a hole.

I’m guessing you aren’t willing to consider that the car companies are just being thrifty rather than extravagant, but ya, it’s a win win for them if they can save on costs at the same time as being seen as fancy.

AlotOfReading 136 days ago

    I’m guessing you aren’t willing to consider that the car companies are just being thrifty rather than extravagant

I work in the industry, I'm well aware. It's an eternal thorn in my side.

    A touch screen is literally one component plus a computer you need anyways.

Not true, and BOM cost isn't the only consideration in manufacturing costs. As I've said in many previous HN threads, the big win for touchscreens is actually on the project scheduling side. That's neither here nor there because my original comment was about the centrally mounted, massive touchscreen a la Tesla as opposed to a smaller, integrated touchscreen. Not buttons vs. touchscreen.

    Flush handles have to do with creating a recess in the body for normal handles. It’s just easier to cut a hole.

That part of a door is manufactured with a series of presses. Whether it's one hole or 16 doesn't make much difference because they're cut all at once.

WalterBright 137 days ago

People who race stock cars will even dip body panels into acid to make the panels thinner. Anything to reduce weight!

recursive 137 days ago

> It's an even more irrelevant consideration for consumers, who could save far more fuel by changing how they drive.

These are not in conflict. The energy you save from drag stacks with the energy you save from "learning how to drive".

hshdhdhj4444 137 days ago

Yeah, but making opening doors a puzzle to solve is an incredibly terrible trade off.

And that’s before we consider the other aspects of these door handle designs that make the cars a death trap.

recursive 137 days ago

The death trap claims come from the internal affordance, which seems to be totally independent from the exterior one.

I have a car with a "novel" handle situation. (Ford Mustand Mach E) The door is operable from the inside with a dead battery. Maybe this particular one isn't as challenging as some of the other designs, but calling it a "puzzle" definitely overstates the case. I think it took me maybe 4 seconds to figure out the first time.

kevin_thibedeau 137 days ago

The Xiaomi SU7 has notably threatened the lives of many of its occupants because rescuers couldn't open the doors from the outside after power loss from a crash or fire. This car is partly responsible for China's new safety regulation banning flush handles.

They add a tiny bit to the efficiency and/or range, they look cool (e.g. serve a gee-whiz marketing purpose), and safety evaluations in the markets where they still exist don't penalize them -- up until now they've had very little against them.

Maybe as legal and reputational backlash spreads the pros will not outweigh the cons. But someone designing a car a decade ago, marketed towards early adopter types, would have had no reason not to.

And I say this as someone who hates these handles designs personally.

I'm not presenting it as a conflict. I'm presenting it as a revealed preference of how much consumers actually try to optimize fuel use. There's significant reductions to be had completely for free (or even with savings by purchasing smaller, cheaper vehicles). And yes, the savings from flush handles are too small to show up in the MPG number.