Frontal Area / Cd numbers

[robfrey]

You have mad Solidworks skills sir!


Rob Freyvogel
#496
AA/BFS

[robfrey]

Also, you might want to reach out to Stand 21 to see if they will give you either a solid model or some good dimensions on the new helmets that are coming out. I think they are a bit bigger.


Rob Freyvogel
#496
AA/BFS

[robfrey]

My original design also had four drive wheels in the rear like yours.
Great minds think alike! Lol


Rob Freyvogel
#496
AA/BFS

[robfrey]

Note that vision out of this canopy design will probably be very distorted.
It is probably too shallow of an angle.
I would not worry too much about aero advantage of the extreme shallow angle. It is probably not worth the trade off of being more complex to manufacture and figuring how to latch / unlatch that behemoth.
Looks great though!


Rob Freyvogel
#496
AA/BFS

[Simspeed]

Note that vision out of this canopy design will probably be very distorted.
It is probably too shallow of an angle.
I would not worry too much about aero advantage of the extreme shallow angle. It is probably not worth the trade off of being more complex to manufacture and figuring how to latch / unlatch that behemoth.
Looks great though!


Rob Freyvogel
#496
AA/BFS

Thanks Rob...the canopy wouldn't open all the way to the front; just the conventional distance to the steering column support.  There's no need trying to draw all that detail into a conceptual model.  Not having driven a low angle profile like this I honestly didn't consider the distorted view which is certainly a concern.  I still believe however the aerodynamic benefit of a low Cd and extremely small frontal area that is to be had from this power train combo for an unlimited liner should not be wasted.  When the potential speed approaches 600 mph, which I believe is within range of this design, I think aero advantage becomes exponentially important all things considered.  One option for the distorted view would be to have the forward most section of the canopy where the driver's line of site is concentrated to be optically ground to remove the distortion.  One of my first designs used a metal canopy with a glass portal in the line of sight at the very nose, but I figured that would be too big of a driving/safety challenge.  Thanks...

[Simspeed]

I'm impressed!

Listening in to a bunch of folks that've been there and done that.

We don't get that all the time here.

(I'm way out of comprehending all of this, but I sure can see and respect a lot of guys who have been there – and someone's listening!)

Thanks Stan...best to be respectful and listen to those who have and build from their experience I believe.  At my age I don't have time to think I can figure this stuff out on my own...I'm old enough to know better.    Thanks...

[Simspeed]

Also, you might want to reach out to Stand 21 to see if they will give you either a solid model or some good dimensions on the new helmets that are coming out. I think they are a bit bigger.


Rob Freyvogel
#496
AA/BFS

That's a great idea Rob...I'll dig into that.  Thanks...

[Simspeed]

My original design also had four drive wheels in the rear like yours.
Great minds think alike! Lol


Rob Freyvogel
#496
AA/BFS

I didn't know that Rob.  I'm just trying to look at limitations inherent in the sport and see if there are any advantages to my design that may offer a way to mitigate some of those problems.  Fortunately, because there's no mechanical drive train issues to overcome I have a lot of freedom in putting components where I think they can return the greatest benefit.  Although it looks like there's a lot of mass behind the dimensional center point of the car, all the mechanical components are relatively lightweight.  The 8 motor controllers for example only weight 120lbs combined according to the mfg. specs. Each gen motor wheel combo should weigh 120 lbs for two motors (60 lbs each) and 54 lbs by volume for the machined aluminum wheel.  That's roughly 816 lbs for the running gear and controllers.  I seen the Cg being well forward of the car center line which is why I changed the design to this configuration.  What does your aluminum front wheel weigh Rob?

[Jack Gifford]

... to be optically ground to remove the distortion...

Is that even possible? Isn't the shallow-angle distortion an inherent result of refraction of light entering/exiting the screen's surfaces?

[Simspeed]

... to be optically ground to remove the distortion...

Is that even possible? Isn't the shallow-angle distortion an inherent result of refraction of light entering/exiting the screen's surfaces?

That's a good question Jack.  I may have assumed incorrectly that optical grinding and polishing could be brought to bear to correct the problem much as is done on modern fighter jet canopies.  I can see your point that higher angle refraction is not something that can necessarily be corrected.  So let's consider an alternative solution involving cameras and video optics systems that show crystal clear color imagery in real time.  I wouldn't be against using such a system to supplement what might otherwise be distorted vision due to light refraction issues through a high angle canopy.  Thanks for point this out...

[robfrey]

Maybe you could cfd both conventional and your design to see what you are actually gaining.
Time to get philosophical.
I can speak with confidence when I say you have many, many battles ahead of you. It is wisest to choose the battles that make the most difference.
What you don't want to end up with is a vehicle with everything being experimental. Time goes by fast and Bonneville has such a short season (limited run and test time).
I have learned to choose components based on "What is going to give me the least amount of issues and still get the job done" vs "the fastest components".
Otherwise you will probably be chasing "new build" gremlins for many, many years and not getting to your goal before "life" happens such as health issues or personal problems.
I can tell that you are very ambitious guy which only speeds rate at which these problems come at you.
We haven't even started  to talk about corrosion issues and how much maintenance is involved from year to year on keeping up with that stuff.
IE, the stuff that you have finished is never really finished.


Rob Freyvogel
#496
AA/BFS

[SPARKY]

The new Bullet trains have a nose that is shaped like a Loon-- the only diving bird that leaves virtually no splash  you may need to change your nose shape to make it less sensative  to yaw

[Simspeed]

The new Bullet trains have a nose that is shaped like a Loon-- the only diving bird that leaves virtually no splash  you may need to change your nose shape to make it less sensative  to yaw

The nose is definitely a work in progress Sparky.  I checked out the loon...I don't think that's a look I'm going for. 

[Simspeed]

Maybe you could cfd both conventional and your design to see what you are actually gaining.

IE, the stuff that you have finished is never really finished.

Rob Freyvogel
#496
AA/BFS

Sound advice Rob...thanks.  I do plan a CFD study once I've arrived at what I consider the most likely shape based on the chassis parameters I've identified.  I think I'm about there with what's physically possible to stuff in this frontal envelope.  Things I'm discussing like refrigerant intercoolers, hydraulic steering, single wheel hub center steering, visibility issues, and electrical drive are all necessitated by the cross section profile I believe is critical to achieving unlimited wheel driven record speed.  I think there are so many quality efforts underway in the conventional sense of mechanical drive trains that taking that approach for me is just a wasted effort.  I'll never have the experience you guys have or the time to develop it in a conventional sense.

Yea, I hope to get down the track too one day, but only if the design concept I use has what I consider a substantial advantage over all the rest.  What I'm coming to love about LSR is the idea that to set unlimited speed records one has to be on the cutting edge of ideas about how to go faster than the best that's come before. Whether I can make any of that happen remains to be seen...but in the arena of ideas I think I can bring a thing or two to the table.  Leastwise, I'm enjoying letting my imagination roam with the possibilities.  Thanks for helping to keep me in touch with reality Rob...

[robfrey]

Like I said. I like the way you think BIG!
I also like your approach about designing the whole car, then deciding if you will actually build it. Not many people think this way.
You are certainly welcome to hang out in our pits this year. After seeing more closely on how the game is played, it will probably influence your design a bit even if it is witnessing what we do wrong. You can just as much from that.
Tom Burkland influenced our design quite a bit just from his emails about what he was experiencing driving down the salt. It was invaluable.


Rob Freyvogel
#496
AA/BFS