Diamonite Electrathon America Racer

Functional Artist

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Winter :(

We gots a bunch of snow recently
...with some snow drifts ~2' (24") deep :furious2:
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Also, It got so cold (~-15*) that I found some ice ferns on a couple of the North facing windows of my house o_O
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Natures art ;)
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Can't do much outside
...so, lots of time for more research & contemplation :thumbsup:

This video discusses reasons for automotive undertrays & diffusers pretty well
...& illustrates much of the info with computer simulated air flow
...& pressure difference visuals :cornut:
 

Functional Artist

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TMI?? (thats Too Much Info...for the OG"s)
...& (thats Old Goats for the...um...never mind) :roflol:

Just tryin' ta give you'all an insight
...as to "where I'ma commin' from" :cheers2:

OK...back to the CAD model

Let's take a closer look at "what I'ma thinkin' for" the bottom side :innocent::devil2:
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So, I'ma thinkin the front air intake will "go" from the front "edge"
...to just behind the front wheel well
...about here ;)
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Then there will be a ""flat" or horizontal area (just under the centrally located battery box) :thumbsup:
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Some specs
The "nose" intake ~16" wide x ~2" tall
...narrows down to ~12" in between the wheel wheels x ~1" tall
...then, the air flow "splits"
...& gets "channeled" into (2) narrower ~5" wide passageways
...while getting sped up & more energized
...as it (air flow) "rushes" toward the throat of the diffuser tunnels

Then, the air starts to expand
...while flowing into the 6"wide throat of the tunnel
...& then, flows out from under the car
...thru the (2) 6" wide x 18" tunnels
...that can "raise" up to as much as ~12" tall at the rear of the body :2guns:
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The body would extend down on the sides
...& the wheel well area would be "sealed" off, from the air flow, a bit
...like this
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Could also have some kinda "air guides"
...maybe like this :unsure:
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Another view
SAM_6646 (2).JPG
 

Functional Artist

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How fast are you planning on going?
🙃
Hey WTR,

Well, my Polaris & Sequoia EA race cars both "top out" ~25MPH with a 12S or 13S battery pack
...or nearly 30MPH when "running" with a 14S or a 15S battery pack
&
Both of those racers have heavy steel space frame chassis
...& don't hardly have any aero or "streamlining" by body panels

This monocoque chassis should be a lighter (hopefully)
...with some (trying for lots of) thought into aero &/or streamlining :thumbsup:
&/so
Maybe up into the mid 30's
...or nearly 40MPH :cornut:

Here is an excerpt from the EA rule book ;)

AERODYNAMICS
Aerodynamic drag increases rapidly the faster you go, enough to be a deciding factor over the duration of the race. Wind resistance has a noticeable effect above 15 mph, and grows exponentially as the speed increases. Aerodynamic drag is the result of speed, frontal area and length of the vehicle and the shape of the body shell.
 

Functional Artist

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Hey Denny,
1.) 20 MPH is probably the most speed, most folks could "handle" on an average EA track (parking lot or road course) :thumbsup:
2.) I'm getting 20MPH - 30MPH using a 1.2HP motor :sifone:
Q: how fast could an EA racer attain with a 1.2HP engine? :innocent:
Q2: Could it even move, a kart/racer with a driver aboard?? :devil2:
 

Functional Artist

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Sarcasm doesn't translate well.
😆
Just busting your balls dude.
I admire your creative brain. Your thought process far exceeds most.
Hey WTR,

Ohhh the sarcasm...:sarcasm:

Thanks...my friend :cheers2:

Sometimes it's a (+) & sometimes it's a (-) o_O

More thoughts :thumbsup:

I heard/read somewhere "As speed doubles, the effects of aero quadruples" (sound correct??) :unsure:
...& if so/as such

I was thinking/for example/hypothetically/for discussion purposes, let's say:
...~1lb. of down force could be created when going ~10MPH
...&/or when going ~20MPH, ~4lbs. of DF, could/should be created
...& then, if going ~40MPH (if we ever get going that fast) maybe ~8lbs. of DF, could be created
&
On a ~300lbs. racer an extra lb. of down force, @ ~10MPH, could/would be helpful
...& potentially ~4lbs. of DF @ ~20MPH...even more so ;)
...&/or/even/maybe ~8lbs. of DF when cruisin' along at ~40MPH :auto:
SAM_6660 (2).JPG
 

Functional Artist

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Another view

Let's look at "it" another way :cheers2:

More drawin's
...& some more expanded explain-ation(s) :smartass:
SAM_6654 (1).JPG
Havin' the front of the racer "blocked off"
...or not
...isn't a big deal, while just sittin' still
SAM_6655 (1).JPG
When driving along
...& having the front of the racer blocked off
...a lot less air would flow under the racer
...but, IIUC (if I understand correctly) a high(er) pressure area (drag) would be created in front of the racer
...& the faster the racer "goes' the higher that pressure (drag) would get
&/also
As a "Free Bonus" a low(er) pressure area (another form of drag) forms behind the racer
& (remember)
The faster the racer "goes" the higher the pressure (more drag) that is exerted, on the front of the racer
...& /also, (in turn) an even lower pressure forms behind the racer (even more drag)
SAM_6656 (1).JPG
But, think of this...
...even "if" the "fancy" shaped floorboard, doesn't actually create any noticeable down force
...the undercar air flow, along with the Venturi effect, should still "inject" some high(er) pressure air
...into the "known to be created" low pressure, area behind the racer ;)

* So, to re-interate
...it seems like having air flowing under the racer
...& thru some venturi tunnels, would help reduce the drag, on the racer, in (2) different ways

1.) From the front, of the racer
...by allowing the higher pressure air (that has built up)
...to "vent" under the body
&
2.) By injecting that "manipulated/conditioned" higher pressure air
...into the lower pressure area, behind the racer
...should help reduce drag too :wai:
SAM_6657 (1).JPG
 

Denny

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But chasing downforce also induces drag. There’s even an old law about this. Energy can not be created or destroyed. It can only be transformed. So by building in the front you’re gettin screwed in the back so to speak.
 
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