silly question maybe but....Isnt 1.9 sec kind of harmful?

[gilscales]

Yes - all high-g thrill rides and rollercoasters should be neutered with immediate effect.

Carousels and tea-cup rides - that's the future.

But a car is not the equivalent of being strapped into a rail-gun at the fair, where you have no control.

I think it's reasonable for Tesla to assume that if you're in the market for a hypercar then a "I want my Mommy / Bring it on" option screen is pointless. The entire car screams "Bring it On!"

Yet even if Plaid is the default whenever you turn the car on, it's not like you HAVE to use it. You still have full control of your right foot. (And there will be logs to prove that)

Tesla owners can choose to press pedals and grin at the same time - it's a thing

But I predict that Big Auto will turn into Concern Trolls over this. They will finance "research" that says that the human body/eye/brain is impaired by 0-60 times of less than 2 seconds on a level equivalent to some concerning amount of alcohol. Because - concern. And of course a few owners will wrap them around trees and stick them into ditches, which will deepen the concern of all those with vested interests.

OK this is just my experience and I'm sure its a rarity but while waiting to configure my RWD 3 the Buena Park Tesla dealer loaned me a P100DL for an overnight trip and I must have done 7 or 8 launches that each time made me start to black out, I am not a roller coaster person, tosses my bubble to much, makes me nauseous, I kept thinking "try it again, you'll get used to it" I never once saw 60 on launches because I felt that if I did not let up I was going to black out so I immediately let up as soon as my vision blurred and even after all those attempts I found that for me I could not launch this hard safely so I quite trying, after all that would I get the P3D if the option was available at the time I configured? Hell yeah, cause even in small doses that speed is addicting!

 

[D.E.]

Perhaps, but the issue here is that the 3G's I was referring to was 3G's pushing straight down through your body from your head to your butt. That is how we test fighter pilots. We spin them in a centrifuge to get up to 9 G's (or more) in the axis that pushes the blood out of your brain and towards your feet. Not 3 G's from front to back, which is primarily what a car does. The reason even 3G's from your head to your feet can cause the issue is that all the blood runs out of your head into your lower abdomen, buttocks, etc and away from your brain. There really isn't the same sort of reservoir for blood to run to and lower brain perfusion with a front to back acceleration, and there isn't a tendency for G's of acceleration along that axis to directly push the blood down away from your head. Even for pregnant women (I am a maternal-fetal medicine physician as well as an Air Guard flight surgeon, so I do frequently consider pregnant women as you suggested), the issue is primarily when that the physiologic pressure of the uterus on the IVC and the slowed reaction of the arterioles to react to a drop in BP and less blood going to their brain. Same for people sensitive to postural changes. That is something causing your BP to drop because you stood up or sat up, and the change leads to blood dropping away from your head and your BP not keeping the pressure up—not a change in front to back movement of blood. Also, for the record, both myself and others who fly in high-G fighters manage into our 50's and 60's and even on high blood pressure meds. So I am still a bit skeptical and just don't see how 1.5 G's directed from front to back can really cause that much of a drop in BP in anyone but the most frail, but perhaps there is some biologic variation or people living right on the edge.

I am willing to postulate that maybe any dizziness felt is more related to the acceleration in your semi-circular canals just making some people feel a little dizzy, especially if the acceleration produces a slightly turning of the head and you induce motion in another axis. Maybe my calculations are wrong somehow, and it really is more than 1.5 G's.

I guess we will just have to see what the accident rate is when it rolls out!

I don't think this is a matter of blood displacement into the pelvis. I'm sure fighter pilot testing uses a worse case scenario. As you point out, that is less of a problem with anterior directed acceleration. With anterior acceleration there will still be passive vascular dilation posteriorly. There will be passive pulmonary vessel dilation. That is a compliant low pressure system. The heart sits anteriorly in the chest. There are mechanisms that may transiently reduce cardiac output.

I don't mean to tell you your business but acute caval compression from a gravid uterus is mechanical and all the arteriolar dilation in the world isn't going to help until the caval compression is relieved and cardiac output is restored. I think I may be considering a more severe aspect.

The acceleration related lightheadedness may not be purely cardiac output related. I think it is probably most likely, though.

I don't think the semicircular canals are responsible. That would cause vertigo rather than lightheadedness. I specifically avoided the term “dizziness” because it does not differentiate between lightheadedness and vertigo.

Anyway, the mechanism of the lightheadedness perhaps isn't the main concern here. I can tell you some people can and do get lightheaded. I think it probably does involve regional blood flow but that is just an opinion. I can tell you subjectively it feels similar to postural hypotension. It remains to be seen whether the symptoms can be directly correlated to increased accident rates and whether any specific full acceleration accident can be attributed solely to lightheadedness.

BTW, thanks for your service to our fighter pilots. They are amazing and they are woefully underpaid for what they do.

 

[SDRick]

I think this is much to do about nothing. "If you can't stand the heat, stay out of the kitchen". Actually, this is more about common sense. I am sure some are sensitive to blacking out. Those that are sensitive would most likely not be in the market for this type of vehicle.

 

[Ludalicious]

I highly doubt the roadster will make anyone who daily drives a Tesla weezy. A 8 second street car is extremely dangerous in the wrong hands though.

I do have one concern "Tires"

After I launch my P100D it rips the tires right up leaving rubber all over the side of my car. Its really hard to explain but it's more of a rubber dust. Only happens on launches. If the torque on the P100D is ripping tires apart that easy. I cant even begin to think how bad the Roadster would be on tires.

I'm beginning to think they will require a very special tire to handle the Torque.

 

[aikisteve]

I highly doubt the roadster will make anyone who daily drives a Tesla weezy. A 8 second street car is extremely dangerous in the wrong hands though.

I do have one concern "Tires"

After I launch my P100D it rips the tires right up leaving rubber all over the side of my car. Its really hard to explain but it's more of a rubber dust. Only happens on launches. If the torque on the P100D is ripping tires apart that easy. I cant even begin to think how bad the Roadster would be on tires.

I'm beginning to think they will require a very special tire to handle the Torque.

Of course it will need special tires. The top speed if over 400kph or 250mph. That puts it into Bugatti Veyron and Chiron territory and make for a set of tires that could be upwards of €10k for the set!

 

[12Pack]

My daily driver is a MS P100D, and I have the 2020 roadster on deposit. The only "queasy feeling" I have is a worry about the performance under braking.
With the MS, the initial acceleration is certainly a lot stronger than my weekender ICE performance car, but its performance under braking is far worse. I hope and expect the Tesla roadster as a dedicated sports car does better, or I'll find myself in trouble.

 

[buttershrimp]

My daily driver is a MS P100D, and I have the 2020 roadster on deposit. The only "queasy feeling" I have is a worry about the performance under braking.
With the MS, the initial acceleration is certainly a lot stronger than my weekender ICE performance car, but its performance under braking is far worse. I hope and expect the Tesla roadster as a dedicated sports car does better, or I'll find myself in trouble.

Interesting, I find my car is quite good with braking, quite good. Is there something wrong with your Brembros? Have you driven another P100D? I’m curious to know now though it sounds like you know what you’re doing while driving.

 

[ViperDoc]

I don't mean to tell you your business but acute caval compression from a gravid uterus is mechanical and all the arteriolar dilation in the world isn't going to help until the caval compression is relieved and cardiac output is restored. I think I may be considering a more severe aspect.

The acceleration related lightheadedness may not be purely cardiac output related. I think it is probably most likely, though.

This is a really interesting question (as an academic doc, I am always willing to consider new data!). Maybe there is enough "passive" space in the pulmonary system to keep some blood from being pushed forward into the heart, but I don't know. One of my other flight doc colleagues here with me today is a heart/long transplant surgeon who ran the program at The Brigham for years. I will have to ask him what he thinks.

You are absolutely right on the mechanical part of the gravid uterus. Arteriole support won't help with that. But in pregnancy, there is another issue, and that is the postural hypotension that leads to lightheadedness in some women that is exacerbated by a slowing of the arteriole response to drops in blood pressure during pregnancy (and this can affect women early in pregnancy before there is significant uterine compression). I was making reference to both of those effects.

Finally, I did appreciate your use of light-headedness v. vertigo. I am not so sure the affected parties are so precise though.

In any case, I look forward to the day we can test our theories!

 

[buttershrimp]

Jesus guys, let's not don't overthink it, when I hear hoofbeats in Texas, I think horses not zebras! This isn't pooling in the venous system or parasympathetic.... think sympathetic baby! We are launching in Teslas! A lightheaded feeling is most likely going to be due to subtle hyperventilation.... I bet pulse rates are high, muscles clenched, asses tight. Think panic attack that doesn't feel like a panic attack because you are doing something that explains your symptoms! Next time this happens breathe into a paper bag and relaunch. LEt's go!

 

[D.E.]

Jesus guys, let's not don't overthink it, when I hear hoofbeats in Texas, I think horses not zebras! This isn't pooling in the venous system or parasympathetic.... think sympathetic baby! We are launching in Teslas! A lightheaded feeling is most likely going to be due to subtle hyperventilation.... I bet pulse rates are high, muscles clenched, asses tight. Think panic attack that doesn't feel like a panic attack because you are doing something that explains your symptoms! Next time this happens breathe into a paper bag and relaunch. LEt's go!

Well, there is always room for other thoughts.

Maybe an experiment is in order. I could try it as a passenger. If the lights go out, that'd be worth knowing. If not, perhaps it is just a matter of getting some experience to quell the psyche. That'd be best for me. I'm still juvenile enough to want the most badass car around.

 

[12Pack]

Interesting, I find my car is quite good with braking, quite good. Is there something wrong with your Brembros? Have you driven another P100D? I’m curious to know now though it sounds like you know what you’re doing while driving.

You are right - actually does quite well for a heavy large car. Its just that not (m)any heavy cars accelerate like it so I am carrying more speed than I should. Also does not transfer a lot of weight to the front due to lower C of g, hence does not get the the usual trail-braking/turn-in benefit so you have to be a bit careful braking hard into a bend.

 

[aikisteve]

You are right - actually does quite well for a heavy large car. Its just that not (m)any heavy cars accelerate like it so I am carrying more speed than I should. Also does not transfer a lot of weight to the front due to lower C of g, hence does not get the the usual trail-braking/turn-in benefit so you have to be a bit careful braking hard into a bend.

I've always been taught never to brake in the bend. You brake before it (always in a straight line) and start accelerating halfway through it.

 

[buttershrimp]

Well, there is always room for other thoughts.

Maybe an experiment is in order. I could try it as a passenger. If the lights go out, that'd be worth knowing. If not, perhaps it is just a matter of getting some experience to quell the psyche. That'd be best for me. I'm still juvenile enough to want the most badass car around.

I've always been taught never to brake in the bend. You brake before it (always in a straight line) and start accelerating halfway through it.

I was taught the same, but I’m no race car driver... just exceptionally good looking and cool while driving my Tesla

 

[Nded]

I've decided to not do any plaid launches with pregnant passengers in mine.

 

[buttershrimp]

I've decided to not do any plaid launches with pregnant passengers in mine.

I’m pretty sure that will guarantee you’re passengers will be carrying your baby after if you know what I mean.... wink wink nudge nudge... more like P-getting-laid mode!

 

[wdolson]

In WW II Allied pilots were having problems with blacking out in tight turns. Up to that point when fighters got into turning fights, it was at low enough speeds that g forces were not a serious problem. As planes got more powerful, the g forces got worse. A number of fighter pilots were killed when they blacked out and spiraled in and some were almost killed only to come to in time to pull out.

In 1945 the US introduced g suits which squeeze the torso and keep the blood more or less in place during high g. It allowed fighters to dog fight more aggressively. Some pilots turned so tight they popped rivets on the wings.

Since then g suits have become standard, but many modern fighters can turn tight enough to defeat g suits.

The launch of the new Roadster is under the acceleration seen with jets on catapults, but those crew have g suits. I think I read somewhere that some custom dragster drivers (is it called top fuel) wear g suits. Some of those cars can accelerate much faster than any street car.

 

[buttershrimp]

In WW II Allied pilots were having problems with blacking out in tight turns. Up to that point when fighters got into turning fights, it was at low enough speeds that g forces were not a serious problem. As planes got more powerful, the g forces got worse. A number of fighter pilots were killed when they blacked out and spiraled in and some were almost killed only to come to in time to pull out.

In 1945 the US introduced g suits which squeeze the torso and keep the blood more or less in place during high g. It allowed fighters to dog fight more aggressively. Some pilots turned so tight they popped rivets on the wings.

Since then g suits have become standard, but many modern fighters can turn tight enough to defeat g suits.

The launch of the new Roadster is under the acceleration seen with jets on catapults, but those crew have g suits. I think I read somewhere that some custom dragster drivers (is it called top fuel) wear g suits. Some of those cars can accelerate much faster than any street car.

Great post! So what are the rules of speeds and Gs upon aircraft carrier launch?

 

[D.E.]

Great post! So what are the rules of speeds and Gs upon aircraft carrier launch?

Carrier launches of fighters with steam catapaults are on the order of 3-4 g. One fellow calculated 3.2g. That was 0 to 170 in 2 seconds.

They now have some electric catapaults that are a little gentler. That helps the planes last longer.

 

[wdolson]

I think big difference is electric catapults do a smooth acceleration over the entire length of the boost, but steam catapults have a stronger push at the start that drops off at the end. As you said, less stress on the airframe. Less stress on the crew too.

 

[buttershrimp]

I think big difference is electric catapults do a smooth acceleration over the entire length of the boost, but steam catapults have a stronger push at the start that drops off at the end. As you said, less stress on the airframe. Less stress on the crew too.

Wow. So what’s the catch? If we are talking 0-170 mph in 2 seconds, how is something as slow as the next gen roadster (lol) going to be bad for health?