Frontal Area / Cd numbers

[Simspeed]

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[SPARKY]

you may be running afoul of the SCTA definitation of a car in that it has to have tow frt steering wheels
Rules 3 L and 4 D

[Simspeed]

you may be running afoul of the SCTA definitation of a car in that it has to have tow frt steering wheels
Rules 3 L and 4 D

Well then Sparky looks like I'll have to add back that second front wheel. Only this time I can duplicate the sprung center hub design for both steering wheels with a common tie rod to the hydraulic steering box.  Thanks for identifying that requirement... Terry

[SPARKY]

Be aware that the frts have to have a measurable difference in their foot print to not be considered a Motorcycle I have heard. Higginbotham's was about 1/4"

[Sumner]

you may be running afoul of the SCTA definitation of a car in that it has to have tow frt steering wheels
Rules 3 L and 4 D

Well then Sparky looks like I'll have to add back that second front wheel. Only this time I can duplicate the sprung center hub design for both steering wheels with a common tie rod to the hydraulic steering box.  Thanks for identifying that requirement... Terry

While we are on the subject you might also consider Rule 1.N Course Damage.  I'd run your idea of deploying the tail cone by them also.  They might feel that could result in course damage.

I'd also reconsider the idea of the first chute deploying the second chute.  What if the first didn't deploy?  I personally feel they should be independent systems.  Also you don't usually want the second chute to deploy immediately.  They are different sizes and maybe types and you normally want the car to decelerate for a period of time on the first before deploying the second.

Sumner

[Simspeed]

you may be running afoul of the SCTA definitation of a car in that it has to have tow frt steering wheels
Rules 3 L and 4 D

Well then Sparky looks like I'll have to add back that second front wheel. Only this time I can duplicate the sprung center hub design for both steering wheels with a common tie rod to the hydraulic steering box.  Thanks for identifying that requirement... Terry

While we are on the subject you might also consider Rule 1.N Course Damage.  I'd run your idea of deploying the tail cone by them also.  They might feel that could result in course damage.

I'd also reconsider the idea of the first chute deploying the second chute.  What if the first didn't deploy?  I personally feel they should be independent systems.  Also you don't usually want the second chute to deploy immediately.  They are different sizes and maybe types and you normally want the car to decelerate for a period of time on the first before deploying the second.

Sumner

Yes, good point Sumner.  I'm still looking at different chute designs to find something I'm happy with.  I have other issues to deal with on the gen/motor dimensions.  I incorrectly drew the width of the motors to half of the 80.4 mm they should have been.  Not sure how that happened but it will increase the width of the outboard wheel pods more than I'm willing to allow as an increase to total frontal area.  I'll either have to delete the outboard wheels or go back to inboard motors and drive axles running out to the wheels to keep the pods thin as they are now.  I'm working on the redesign now.  Thanks... Terry.

[Simspeed]

Major design changes for Version 4.8.  I've added the second front wheel to meet SCTA requirements.  The hub center design works well for both front wheels giving a maximum of 16° turning radius lock to lock. I've had to rethink the IC/gen/motor combo because I used the wrong gen/motor width dimension in my previous drawings. 

Breaking the 4 rotor IC engine down to two rotors paired to two gen/motors turned sideways then stacking that combo into 4 pairs back to back works better than the linear arrangement shown before.  Here we can optimize intake runners and exhaust headers to maximize flow to and from the turbos. It also allows a better layout for the dry sump pumps, cooling lines, and electrical power lines back to the controllers. It also lowers the height of the engine for better driver visibility.  This will necessitate custom rotor/gen/motor housings where one rotor and one gen/motor will be paired together in a single housing then mated to a second rotor/gen/motor housing to make up two rotor/gen sections.  Rotors counter rotate in this design for opposing two rotor banks but that fine because the electrical polarity is switchable.

The bigger problem turned out to be the width of the outboard wheel pods due to the wider gen/motor housings.  I came up with a better design that moves all four drive wheels back inboard but I'm staggering and overlapping the wheel placements to put each wheel in it's own track on the salt.  This required flaring out the body behind the driver which increased frontal area from 3.6 to 5.23 but that's much better than the 7.93 sq.ft. of the outboard wheel design.  The car has grown in length again to just over 37'.

I've decided to incorporate active aero into the chute tail cone section.  The rear wing and tail cone will pivot at the front to raise the wing angle to increase downforce thus adding weight to the drive wheels as per Rob's Carbinite design.  As speed increases the wing will lower to zero angle of attack producing zero drag and downforce.  At the end of a run the wing will raise again opening the tail cone for chute deployment and adding drag to help slow the car.  The chute packs will be ejected into the slipstream using mechanical or pneumatic ejectors.

Don (RaceEngineer) turned me on to the Szorenyi 3 rotor IC design out of Australia.  I was aware of their earlier 4 rotor design but it didn't appear feasible to me.  This new 3 rotor design has a number of advantages over the Wankel engine that Mazda manufactured.  I'm going to follow up with the Szorenyi people to see where their prototype efforts stand.  Any feed back from forum member on this latest design will be appreciated.  Thanks... Terry.

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[Peter Jack]

What's going to be the effect of lifting the tail at maximum speed to initiate braking? It looks to me like there will be an instantaneous huge load increase well behind the rear wheels, thus unloading the front end. Would it not be better if only the center section was raised and the majority of the flat area keeps the aerodynamics stable?

Keep thinking, this is fun. 

Pete

[Peter Jack]

The other thing you may want to keep in mind is that you have to handle this beast. You only have an hour to turn around, service and get back on track if you want to set an FIA record. You also have to load and unload the car. These requirements can seriously alter some of the other requirements you're trying to meet.

Good luck and keep us all thinking.

Pete

[Seldom Seen Slim]

Quick turnaround:  I sure wish I could find pictures of the Burkland's turntable thingie for speeding the turnaround.  It was a slightly raised platform that Tom would coast the car onto after the down run.  The car stopped on the top - a turntable!

While the crew attacked the car the table rotated 180 degrees, some people walking backwards while changing plugs and filling tanks, some walking frontwards (on the other side of the car) - and stopped with the car pointing at the start line.  Finish the servicing, roll the car back to the surface, and viola, all ready.

It was quite the symphony in motion.  Thanks for bringing back the memory.