I’ve been looking at various configurations and the latest one is to have four smaller motors, one for each wheel, to provide the power. I found a BLDC (BrushLess Direct Current) motor that can make up to 80 kW and so four of them would make for a rather powerful car. Since they’d be driving the wheels directly, I can’t use the full 8,000 rpm as at top speed (I’m guessing about 260 km/h) the wheels only need to do about 2,500 rpm, so a small reduction system would be needed, and that’s actually a good thing as it would increase the torque at the wheels also by about that much.

The other benefits should be that I could dial-up how much power I wanted the front wheels to make in proportion to the rear. I’m guess that for my car I’d want between 30% – 40% of the total power to the front wheels. Another handy trick much be torque-vectoring, that’s where there’s a lateral g-sensor in the car and you’d have a pre-programmed map that would increase the power to the wheels on the outside of the corner and decrease it to the inner wheels. That’s because if the car is well set-up, at maximum cornering power there’s not a great deal of weight on the inside tyres, thus they can start to slip relatively easily.

I’ll have to see if I can find a way of detecting tyre slip by having a camera look at the road surface as it goes past. Normally you’d just compare an undriven wheel rpm with the driven wheel, and if it’s more than about 5% then you have to start reducing the power to the driven wheels. Can’t do that with a 4WD car, so perhaps some optical gear can help with that.

The battery pack mass may not be too bad, another guestimate could have it under 200 kg, and that’s liveable.

FWIW, the car would look a bit like this -

If I get the aero & suspension right if should generate up around 2.5 G’s lateral power.

Spiny Norman said:

I’ve been looking at various configurations and the latest one is to have four smaller motors, one for each wheel, to provide the power. I found a BLDC (BrushLess Direct Current) motor that can make up to 80 kW and so four of them would make for a rather powerful car. Since they’d be driving the wheels directly, I can’t use the full 8,000 rpm as at top speed (I’m guessing about 260 km/h) the wheels only need to do about 2,500 rpm, so a small reduction system would be needed, and that’s actually a good thing as it would increase the torque at the wheels also by about that much.

The other benefits should be that I could dial-up how much power I wanted the front wheels to make in proportion to the rear. I’m guess that for my car I’d want between 30% – 40% of the total power to the front wheels. Another handy trick much be torque-vectoring, that’s where there’s a lateral g-sensor in the car and you’d have a pre-programmed map that would increase the power to the wheels on the outside of the corner and decrease it to the inner wheels. That’s because if the car is well set-up, at maximum cornering power there’s not a great deal of weight on the inside tyres, thus they can start to slip relatively easily.

I’ll have to see if I can find a way of detecting tyre slip by having a camera look at the road surface as it goes past. Normally you’d just compare an undriven wheel rpm with the driven wheel, and if it’s more than about 5% then you have to start reducing the power to the driven wheels. Can’t do that with a 4WD car, so perhaps some optical gear can help with that.

The battery pack mass may not be too bad, another guestimate could have it under 200 kg, and that’s liveable.

FWIW, the car would look a bit like this -

If I get the aero & suspension right if should generate up around 2.5 G’s lateral power.

If you get it all going you should just get handed your degree :)

Are you still doing it?

sibeen said:

If you get it all going you should just get handed your degree :)

Are you still doing it?

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

Spiny Norman said:

sibeen said:

If you get it all going you should just get handed your degree :)

Are you still doing it?

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

Everybody struggles with the maths.

Spiny Norman said:

sibeen said:

If you get it all going you should just get handed your degree :)

Are you still doing it?

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

btm said:

Spiny Norman said:

sibeen said:

If you get it all going you should just get handed your degree :)

Are you still doing it?

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

Sick fucker.

sibeen said:

Sick fucker.

Concur.

Stunk at maths in high school.

Then, Navy says ‘here’s navigation, here’s spherical trigonometry’.

Gee, thanks.

Got by somehow, managed to avoid the yellow features (solid bits) on the charts, no tragic shipwrecks with tremendous loss of life (some secrets i’ll take to my grave).

People who do maths for fun: very, VERY , suspect.

sibeen said:

btm said:

Spiny Norman said:

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

Sick fucker.

I knew Btm was strange but that’s perverse!

Witty Rejoinder said:

sibeen said:

btm said:

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

Sick fucker.

I knew Btm was strange but that’s perverse!

I’ll admit to enjoying maths, but I’ll also admit that the higher engineering maths has long gone. It really is a matter of use it or lose it, and I just don’t have the job where I use it.

sibeen said:

Witty Rejoinder said:

sibeen said:

Sick fucker.

I knew Btm was strange but that’s perverse!

I’ll admit to enjoying maths, but I’ll also admit that the higher engineering maths has long gone. It really is a matter of use it or lose it, and I just don’t have the job where I use it.

I once had an econometrics class where the entire whiteboard was covered with equations 3 and 4 times a lecture. I took it all down but taking it in? Never.

Witty Rejoinder said:

sibeen said:

Witty Rejoinder said:

I knew Btm was strange but that’s perverse!

I’ll admit to enjoying maths, but I’ll also admit that the higher engineering maths has long gone. It really is a matter of use it or lose it, and I just don’t have the job where I use it.

I once had an econometrics class where the entire whiteboard was covered with equations 3 and 4 times a lecture. I took it all down but taking it in? Never.

With me it’s got to the stage of “Oh, fuck, WTF happens there?” which in the old days would have required a lot of ODEs, Laplace transforms, integrals out the waazoo etc, etc. Now days I can just throw 99% into a simulation program to work out the details.

One thing I will note about this is that for new engineers I’m totally against them just using the simulations. You do need to slog through the maths to get a feel for what is the underlying processes.

sibeen said:

btm said:

Spiny Norman said:

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

Sick fucker.

Well, yes. But you knew that.

captain_spalding said:

sibeen said:

Sick fucker.

Concur.

Stunk at maths in high school.

Then, Navy says ‘here’s navigation, here’s spherical trigonometry’.

Gee, thanks.

Got by somehow, managed to avoid the yellow features (solid bits) on the charts, no tragic shipwrecks with tremendous loss of life (some secrets i’ll take to my grave).

People who do maths for fun: very, VERY , suspect.

“The good Christian should beware of mathematicians and all those who make empty prophecies. The danger already exists that mathematicians have made a covenant with the devil to darken the spirit and confine man in the bonds of Hell.”
          — Saint Augustine

sibeen said:

One thing I will note about this is that for new engineers I’m totally against them just using the simulations. You do need to slog through the maths to get a feel for what is the underlying processes.

That’s what i got from my Nav. instructor.

He’d done the RN’s ‘Long N’ course. That meant that if he didn’t know it, it was because it hadn’t been thought of yet, and it probably wasn’t possible anyway.

He would not countenance the use of calculators. Pencil and paper, and nautical tables. And the tables were an ‘if-you-were-lucky’.

captain_spalding said:

sibeen said:

One thing I will note about this is that for new engineers I’m totally against them just using the simulations. You do need to slog through the maths to get a feel for what is the underlying processes.

That’s what i got from my Nav. instructor.

He’d done the RN’s ‘Long N’ course. That meant that if he didn’t know it, it was because it hadn’t been thought of yet, and it probably wasn’t possible anyway.

He would not countenance the use of calculators. Pencil and paper, and nautical tables. And the tables were an ‘if-you-were-lucky’.

I’m not into it because “that’s what I had to do” it is because if you only use simulations and mathematica, mathcad etc then the ‘feel’ just isn’t there.

sibeen said:

I’m not into it because “that’s what I had to do” it is because if you only use simulations and mathematica, mathcad etc then the ‘feel’ just isn’t there.

As our instructor put it, ‘you’re in an open boat with eighteen other men, whose lives depend on your navigation. You have a sextant, a compass, and a wristwatch. It’s 3,600 nautical miles to safety. It’s been done before. Can you do it?’.

captain_spalding said:

sibeen said:

I’m not into it because “that’s what I had to do” it is because if you only use simulations and mathematica, mathcad etc then the ‘feel’ just isn’t there.

As our instructor put it, ‘you’re in an open boat with eighteen other men, whose lives depend on your navigation. You have a sextant, a compass, and a wristwatch. It’s 3,600 nautical miles to safety. It’s been done before. Can you do it?’.

Well why did you bring us here?

btm said:

Spiny Norman said:

sibeen said:

If you get it all going you should just get handed your degree :)

Are you still doing it?

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

That could be extremely helpful, thanks.
I did have a very good personal tutor a couple of years ago, but he left the uni as they hadn’t paid him in months. All I want is to be able to solve the problems. I don’t care about what they do, how they’re used, nor their history. I just want to know how to shuffle the numbers around.
And I’m quite happy to pay for your time.

FWIW here’s the list of things we have to cover.

Spiny Norman said:

btm said:

Spiny Norman said:

I’m waiting for a reply from the motor company about torque, etc.
At the moment I’m quite some time away from getting an engineering degree and there’s a good chance it won’t happen anyway. The maths is somewhat above my ability.

If I can help with the maths from the other side of the country, Bill, let me know. I found the maths easy, and do it for fun.

That could be extremely helpful, thanks.
I did have a very good personal tutor a couple of years ago, but he left the uni as they hadn’t paid him in months. All I want is to be able to solve the problems. I don’t care about what they do, how they’re used, nor their history. I just want to know how to shuffle the numbers around.
And I’m quite happy to pay for your time.

FWIW here’s the list of things we have to cover.

Yes. I can teach you that. I’ve done all that.
The maths is about all I can handle, it’s the practical that I can’t handle.

For the first 3 parts of module 1 all you need is to be able to draw.
After that it’s just algebra, tossing symbols around from one side of an equation to the other. You can do that.

There are various useful applied maths topics that aren’t included – no statistics and no Fourier analysis.

mollwollfumble said:

Yes. I can teach you that. I’ve done all that.
The maths is about all I can handle, it’s the practical that I can’t handle.

For the first 3 parts of module 1 all you need is to be able to draw.
After that it’s just algebra, tossing symbols around from one side of an equation to the other. You can do that.

There are various useful applied maths topics that aren’t included – no statistics and no Fourier analysis.

Between you & BTM I should stand a chance of passing the course, that would be rather good thanks!
Send me an email at aussie.bill.sherwood@gmail.com so we can sort out how to chat over Skype or Zoom, etc.

Spiny Norman said:

mollwollfumble said:

Yes. I can teach you that. I’ve done all that.
The maths is about all I can handle, it’s the practical that I can’t handle.

For the first 3 parts of module 1 all you need is to be able to draw.
After that it’s just algebra, tossing symbols around from one side of an equation to the other. You can do that.

There are various useful applied maths topics that aren’t included – no statistics and no Fourier analysis.

Between you & BTM I should stand a chance of passing the course, that would be rather good thanks!
Send me an email at aussie.bill.sherwood@gmail.com so we can sort out how to chat over Skype or Zoom, etc.

Maybe start a Calc II thread so others can chime in or perhaps relearn

Spiny Norman said:

I’ve been looking at various configurations and the latest one is to have four smaller motors, one for each wheel, to provide the power. I found a BLDC (BrushLess Direct Current) motor that can make up to 80 kW and so four of them would make for a rather powerful car. Since they’d be driving the wheels directly, I can’t use the full 8,000 rpm as at top speed (I’m guessing about 260 km/h) the wheels only need to do about 2,500 rpm, so a small reduction system would be needed, and that’s actually a good thing as it would increase the torque at the wheels also by about that much.

The other benefits should be that I could dial-up how much power I wanted the front wheels to make in proportion to the rear. I’m guess that for my car I’d want between 30% – 40% of the total power to the front wheels. Another handy trick much be torque-vectoring, that’s where there’s a lateral g-sensor in the car and you’d have a pre-programmed map that would increase the power to the wheels on the outside of the corner and decrease it to the inner wheels. That’s because if the car is well set-up, at maximum cornering power there’s not a great deal of weight on the inside tyres, thus they can start to slip relatively easily.

I’ll have to see if I can find a way of detecting tyre slip by having a camera look at the road surface as it goes past. Normally you’d just compare an undriven wheel rpm with the driven wheel, and if it’s more than about 5% then you have to start reducing the power to the driven wheels. Can’t do that with a 4WD car, so perhaps some optical gear can help with that.

The battery pack mass may not be too bad, another guestimate could have it under 200 kg, and that’s liveable.

FWIW, the car would look a bit like this -

If I get the aero & suspension right if should generate up around 2.5 G’s lateral power.

is there no real benefit of supercharging the engine using batteries to force air in ?? a race is a short time period. if you used a battery pack to supercharge the air in you wouldn’t need to start from scratch or buy expensive wheels

wookiemeister said:

Spiny Norman said:

I’ve been looking at various configurations and the latest one is to have four smaller motors, one for each wheel, to provide the power. I found a BLDC (BrushLess Direct Current) motor that can make up to 80 kW and so four of them would make for a rather powerful car. Since they’d be driving the wheels directly, I can’t use the full 8,000 rpm as at top speed (I’m guessing about 260 km/h) the wheels only need to do about 2,500 rpm, so a small reduction system would be needed, and that’s actually a good thing as it would increase the torque at the wheels also by about that much.

The other benefits should be that I could dial-up how much power I wanted the front wheels to make in proportion to the rear. I’m guess that for my car I’d want between 30% – 40% of the total power to the front wheels. Another handy trick much be torque-vectoring, that’s where there’s a lateral g-sensor in the car and you’d have a pre-programmed map that would increase the power to the wheels on the outside of the corner and decrease it to the inner wheels. That’s because if the car is well set-up, at maximum cornering power there’s not a great deal of weight on the inside tyres, thus they can start to slip relatively easily.

I’ll have to see if I can find a way of detecting tyre slip by having a camera look at the road surface as it goes past. Normally you’d just compare an undriven wheel rpm with the driven wheel, and if it’s more than about 5% then you have to start reducing the power to the driven wheels. Can’t do that with a 4WD car, so perhaps some optical gear can help with that.

The battery pack mass may not be too bad, another guestimate could have it under 200 kg, and that’s liveable.

FWIW, the car would look a bit like this -

If I get the aero & suspension right if should generate up around 2.5 G’s lateral power.

is there no real benefit of supercharging the engine using batteries to force air in ?? a race is a short time period. if you used a battery pack to supercharge the air in you wouldn’t need to start from scratch or buy expensive wheels

you’d position the battery pack strategically to give best grip for the tyres

wookiemeister said:

Spiny Norman said:

I’ve been looking at various configurations and the latest one is to have four smaller motors, one for each wheel, to provide the power. I found a BLDC (BrushLess Direct Current) motor that can make up to 80 kW and so four of them would make for a rather powerful car. Since they’d be driving the wheels directly, I can’t use the full 8,000 rpm as at top speed (I’m guessing about 260 km/h) the wheels only need to do about 2,500 rpm, so a small reduction system would be needed, and that’s actually a good thing as it would increase the torque at the wheels also by about that much.

The other benefits should be that I could dial-up how much power I wanted the front wheels to make in proportion to the rear. I’m guess that for my car I’d want between 30% – 40% of the total power to the front wheels. Another handy trick much be torque-vectoring, that’s where there’s a lateral g-sensor in the car and you’d have a pre-programmed map that would increase the power to the wheels on the outside of the corner and decrease it to the inner wheels. That’s because if the car is well set-up, at maximum cornering power there’s not a great deal of weight on the inside tyres, thus they can start to slip relatively easily.

I’ll have to see if I can find a way of detecting tyre slip by having a camera look at the road surface as it goes past. Normally you’d just compare an undriven wheel rpm with the driven wheel, and if it’s more than about 5% then you have to start reducing the power to the driven wheels. Can’t do that with a 4WD car, so perhaps some optical gear can help with that.

The battery pack mass may not be too bad, another guestimate could have it under 200 kg, and that’s liveable.

FWIW, the car would look a bit like this -

If I get the aero & suspension right if should generate up around 2.5 G’s lateral power.

is there no real benefit of supercharging the engine using batteries to force air in ?? a race is a short time period. if you used a battery pack to supercharge the air in you wouldn’t need to start from scratch or buy expensive wheels

A turbo already does that for free. Would be far more efficient and effective to go hybrid, with the electric motors providing the initial launch and regenerative braking.
But then weight is an issue, and reliability as you now have two systems that can fail.

sibeen said:

Spiny Norman said:

mollwollfumble said:

Yes. I can teach you that. I’ve done all that.
The maths is about all I can handle, it’s the practical that I can’t handle.

For the first 3 parts of module 1 all you need is to be able to draw.
After that it’s just algebra, tossing symbols around from one side of an equation to the other. You can do that.

There are various useful applied maths topics that aren’t included – no statistics and no Fourier analysis.

Between you & BTM I should stand a chance of passing the course, that would be rather good thanks!
Send me an email at aussie.bill.sherwood@gmail.com so we can sort out how to chat over Skype or Zoom, etc.

Maybe start a Calc II thread so others can chime in or perhaps relearn

In the meantime, dig up the “Schaum outline series” books. The Schaum outline “vector analysis” book is a start. It’s better than any other textbook for learning about vectors.