Frontal Area / Cd numbers

[tortoise]

I do have plans to 3d print the body model to some useful scale and see if I can find a wind tunnel or water flow tank that can measure the shape Cd.  If the Cd is as small as I'm hoping it will be that might help me find funding to build it one day.  Never know until I try... 

As long as you're measuring C_d, you might as well compare that long, tall, concave-sided beak with a small, low, rounded one. Or are you thinking maybe the car has trans-sonic speed potential?

[Simspeed]

I've estimated the Cg based on weighted percentages of major components shown within a fore-aft Cg range for total component sets. I started with the premise that the two identical engines balance at the dead center between them and then added Cg points for the furthermost component point back to the rearmost component point.  I then calculated percentages for each and plotted those points within the fore-aft range to arrive at the weighted average distance for all components along the range.  This puts the estimated Cg for the car at 19.58" forward of the engine Cg.  I'll save this and hopefully one day I'll have a finished car to check today's estimate against.  

[Simspeed]

As long as you're measuring C_d, you might as well compare that long, tall, concave-sided beak with a small, low, rounded one. Or are you thinking maybe the car has trans-sonic speed potential?

Hahaha...well you never know tortoise...stranger things have happened.  

But will the small low nose give a better or worse Cd given the loss of the tapered shape below the center line?  Where's the tradeoff?

[tortoise]

But will the small low nose give a better or worse Cd given the loss of the tapered shape below the center line?  Where's the tradeoff?

Neither of us  know about the C_d, really. I'm just thinking about directional stability. I think you'd need more fin on the back to compensate for the proboscis, and that's more drag right there. Speculation, I know, without data. But you'd really want to know how stable it is before you put yourself inside it.

[Simspeed]

I certainly agree with that statement tortoise.  I don't believe this design would ever spin...it'd pencil roll almost immediately I'd imagine.

[dw230]

Because of a lack of interest in Hybrid vehicles the rules are limited to the PRODUCTION category ONLY. The "dozens" of OE manufactured vehicles that would appear if a class was created have gone the way of the C/AIR class. It looks like you are spending time and resources(?) on a theoretical car that can set only theoretical records.

Best bet? Petition SCTA or FIA for a recognized class.

Good luck,

[Stainless1]

Dan, why wouldn't it fit in whatever class the swept volume of the motors would be.  I don't remember anything requiring mechanical connection from the motor to wheels. 
Gasoline powered motors.... 

[dw230]

PRODUCTION category only. If we are talking Hybrid power source.

Not my deal any more. Find an advocate in the SCTA.

DW

[Jack Gifford]

Nobody considers diesel-electric locomotives "hybrids".

[wobblywalrus]

Reply #59 mentions use of water to analyze aerodynamics.  This would be in a flume, is my best guess.  The results would be misleading and it is not a good idea for a lot of reasons.  Use a wind tunnel or a virtual analysis that is intended for the purpose.   

[Seldom Seen Slim]

If my memory is right, water was used in the design of the famous "Charlie Toy" bodywork.  I think the water was moving vertically/the bodywork was vertical, too.

[Simspeed]

This is the type of water tank aerodynamics I'm referring to.
https://www.youtube.com/watch?v=quDLzxmJl5I&t=2697s

[dw230]

Nobody considers diesel-electric locomotives "hybrids".

Trains & stationary engines and don't race at Bonneville.

DW

[jacksoni]

True Dan, but as you are fond of saying, "Don't read into the rule book what isn't there" or words like that.

The passage says " Vehicles using a hybrid POWER (my emphasis) source, such as a gasoline/battery pack, will compete in the equivalent cubic inch class of the gasoline engine." Goes on to talk about the battery pack being sealed and it can't be charged separately or off site etc. Indeed the generators/electric motors are functioning as the "transmission" as has been pointed out- and transmissions are "free, ie unregulated" in all classes.

But as you say, Simspeed better get a formal special construction ruling about this drive train before going beyond computer speeds and horsepower- which of course are a lot of fun and easier to obtain than real ones........... Cheaper than building it and have it called illegal. 

[tortoise]

A project of this magnitude would have one goal: fastest wheel-driven car. Nobody'd much care what SCTA class it fit.