Diamonite Electrathon America Racer

[Whitetrashrocker]

I kinda agreeing with denny. At 30 mph speed aero is not as much as a factor as mechanical drag.
I can see incorporating as much speed aero as you can but your not at a critical state. Dont fret the small stuff yet.
Wheel bearing friction and tire surface area I think would be more important. Im assuming the EA stuff is about endurance, no.

Yarn is used in aviation quite a bit.
Tape a pice in the windshield and you can see how much the slip stream isn't "with" the direction of appeared travel.
A line of yarn strips place down the wing can be a good illustration of how the wing stalls at low speed.

But that kinda like wind tunnel tests. Lol.

I remember a while back watching some salt lake speed record type stuff.
They were doing just a few MPH below 200. No matter what tuning the did they just couldn't Crack that 200.
They decided to place tape along the body gaps to seal them. Cardboard cut outs in the grill to block them and make a "tad" more aerodynamic.
Guess what. They made the few MPH and broke the 200.

Aren't the winners of those endurance races basicly tear dropped with a fully enclosed canopy ?

 

[Functional Artist]

Confirmin' & "pointin' out" (to myself) which "marks" to cut...before cuttin'

Back out ta Nature
...& yup, it's still Winter time
...but, now, I got some wood "scraps" ta burn...free heat

I got the front ends, of all (4) panels trimmed off

Then, took 'em back inside, for some re-assembly

Top view, of the cockpit area

A view from the other side

Front fender/Nose area

 

[Functional Artist]

I kinda agreeing with denny. At 30 mph speed aero is not as much as a factor as mechanical drag.
I can see incorporating as much speed aero as you can but your not at a critical state. Dont fret the small stuff yet.
Wheel bearing friction and tire surface area I think would be more important. Im assuming the EA stuff is about endurance, no.

Hey WTR,

Let's look at this from a ???? to weight ratio "point of view"
...as compared to a full size racecar

Power to weight ratio
Many full-size race cars use ~500+HP to motivate ~3,000lbs.
&
My EA racer uses ~1HP to motivate ~300lbs.

Aero to weight ratio
So/doesn't this mean that the "aero" required to have an effect on a 3,000lbs. racer would be ~10X "greater"
...than the aero required, to have an effect on a 300lbs. racer?

Now, think about the (amount of) aero effects that would be needed to affect a 3,000lbs. vehicle
...as opposed to the (amount of) aero effects that would be needed to affect a 300lbs. vehicle?
&
Now, compare that to "out in Nature"

Think about the amount of breath that would be required to "blow" a small bird away
...as opposed to the amount of breath that would be required to "blow" a mosquito away

 

[Functional Artist]

I kinda agreeing with denny. At 30 mph speed aero is not as much as a factor as mechanical drag.
I can see incorporating as much speed aero as you can but your not at a critical state. Dont fret the small stuff yet.
Wheel bearing friction and tire surface area I think would be more important. Im assuming the EA stuff is about endurance, no.

Also, thinkin' ahead

I'm "currently" only workin' with 48V systems (top speed ~30MPH)
...but, if/when I move up to 60V or 72V or/even 90V systems, I could potentially
...double my speed (to ~60MPH)
...or maybe even triple my top speed to ~90MPH (OMGGGGGGGGGGGGGGGG)

 

[Functional Artist]

I heard someone say..."that still looks pretty HUGE"

Well...I've been kinda cheatin' by usin' my Hell-raiser kart as a sizin' template

Wheelbase ~48"
Overall length ~64"
Track width ~36"

Video/visual of Hell-raiser

 

[Functional Artist]

I agree drag is bad and lift is worse first of all. Second for the speeds we’re running aero is just not as important as mechanical efficiency. And thirdly without a wind tunnel you may as well be peeing into the wind. Everything is just a guess. Break out the yarn and masking tape and go out and experiment.

Hey Denny,

1.) I came across a TV program last evening, about the Wright bros. first "test flights"
...& the "plane" (actually glider) in them tests was not motorized (so low/slow speed)

According to the program, the first "test plane" had a wingspan of ~17'
...& the second (more known) "test plane" had a wingspan of 32'

The main thing that caught my attention was that (according to their educated guesses) they needed a HUGE (~17' wide) wing
...to create enough "lift" for the "test plane" & pilot (driver) to "lift" off of the ground
&
Then, after initial testing (according to the program 1,000+ test flights)
...for V2 they increased (almost double) the wingspan

* This indicates to me that a lot of wing area is required to produce any meaningful "lift"
...at least at slow (under 30MPH) speeds

2.) With knowledge a fellow (or gal) can form/make educated guesses
...which (hopefully) are a bit more...on target
&
Ya gotta have a "test mule"
...that's (hopefully) "goin' in the right direction" (from your educated guesses) to "tuft" first
...that ya can experiment with
...& then, try-n-make improvements...on

3.) Another "way" to look at this:
If a (4-wheeled) racecar weighs (let's say, for round numbers) 3,000lbs. (with driver)
...so, that would be ~750lbs. of "free" gravity provided DF (down force) per wheel

Whereas my (3-wheeled) EA racers, only weigh ~300lbs. with driver (~10X less)
...&/so, that's only ~100lbs. of "free" gravity provided DF, per wheel

Seems like "if" I was "flying" along
...in a 300lbs. racer
...at ~30MPH
...& tried to "take" (navigate) an abrupt turn
...I think would "use up" 100lbs. of DF (per wheel) pretty quickly

 

[Functional Artist]

More on the Bernoulli effect

Let's think about things, we have all seen &/or encountered for ourselves, out "in the real world"

First think of a leaf (like from a tree) slowly floating down a stream

* I brought visuals
...ta help illustrate

When, the leaf, encounters a narrowed area of the stream
..."it" noticeably speeds up while "going thru" that narrow area
...& then, "it" slows back down, to about its previous speed, when it "gets past" the narrowed area

Now, let's "step it up" to full size

Think about a kayak (with pilot) that is slowly floating down a river
...& when the kayak, encounters a narrowed area of the river
..."it" noticeably speeds up while "going thru" that narrow area (technical term-rapids)
...& then, "it" slows back down, to about its previous speed, when it "gets past" the narrowed area
&
I've seen kayaks floating along at relatively low speeds
...that/then, speed up dramatically (like double &/or triple speeds) when going thru a narrowed area or "rapids"
&/so,
It seems like the Bernoulli effect
...can be pretty strong &/or intense
...even on a small/light weight
...(1) person vessel (vehicle)
...&/even while traveling, at relatively low speeds

3.) You're walking down the street & you pass an area where there are (2) walls, buildings, houses (whatever)
...& you notice a stronger wind "flowing" thru the narrowed passage
...than, before reaching &/or after passing that area

IMO these are ALL examples of the Bernoulli effect
...happening out here in the real world
&
I'ma tryin' ta establish, enhance & "harness" some of that effect, under a racer

Ya know...Functional Art

 

[Denny]

I guess I just don’t understand why you would need extra gravity at such low speeds.

 

[ezcome-ezgo]

The only people who want less gravity are ascending astronauts. Even people on airplanes need gravity to get back home. My wife has an irrational fear of going over tall bridges, afraid that gravity will either fail and let her fly off the road, or that it will overwhelm and bring the bridge crashing down.

Perhaps a "better" obsession would be to focus on reducing drag. If you try to push a sheet of vertical plywood along at 30 mph, you'll need a bunch of power. If you place it on it's side, you could probably pull it with a bicycle. Reducing wind resistance is a noble cause for any vehicle.

 

[ezcome-ezgo]

This vehicle allegedly is capable of producing 6000lbs of downforce: https://bringatrailer.com/listing/2022-enviate-hypercar-evo-pikes-peak/

 

[Functional Artist]

I guess I just don’t understand why you would need extra gravity at such low speeds.

Hey Denny,

If we were building a racer that only did "sprints"
...or we just wanted to go straight, I agree any extra gravity/weight would be No Bueno

But, these racers are usually "run" on curvy road courses
...so, we have to have good maneuverability
...to be able to maintain a good bit of speed
...thru the curves & in turns too

The kool thing about aero created DF (down force) is that it only "happens" as speed increases (when it would be more helpful)
...so, you're not "in essence" carrying around extra weight/gravity...all of the time

It only appears when ya need it
&
ASIU (as I understand) these effects increase or get stronger
...the faster the vehicle travels (when it would be even more helpful)

Kinda like the invisible "Hand of...Nature"
...lightly "pushin' down" on the racer
...helping it "hug" the road
...while tryin' ta go as fast as possible

 

[Functional Artist]

FMO (for more info)
...& ta try-n-help explain...a bit more

This video has lots of detailed, under car aero info
...why it's important (on a race car)
...a "ride along" portion (with G force info)
...& is using "flexible" side skirts

 

[Functional Artist]

OK then, lets bend some pipe
I wasa runnin' low on 1/2" Schedule 40 water pipe
...so, I stopped by the Metal Store

* I wasa gonna buy (2) full 21' "sticks" of pipe
...but, they only had (1) full "stick"
...& (1) short(er) piece

Let's start with the trailing arm
...so, I measured & marked (2) pieces
...& then went ta bendin'

* Here's Emmy doin' an inspection

(1) piece bent beautifully...fine
...but, (1) piece kinked (technical term)
...then, another piece kinked...too

WTF they are all the same stuff...right??

Yup, they seem ta be

This is a kink

This is a nice bend (front view)

45*(ish) view

A side view

I got (2) pieces bent successfully...but WTF??

 

[Whitetrashrocker]

Look at where the seam is compared to your bend.
Easier to see on the inside surface.

 

[Functional Artist]

Look at where the seam is compared to your bend.
Easier to see on the inside surface.

Hey WTR,
Well...let's take a look

These are the (2) pieces that bent properly

The seam of the left piece seems ta be @ ~6:00
...& the piece on the right seems ta be @ ~9:00ish

Another view for seam clarity

These (2) pieces were cut out of the same piece of pipe
...then, I got (2) roll bars outta it too

The others (with failed bends) were out of the other "shorter" piece of pipe

* I've bent A LOT of pipe over the last 10 - 15 years
...& have only had this happen once before (back in 2022 or 2023)

The way it kinks, kinda gives me tube vibes
...as steel tube kinks, easily, when bent with a pipe bender

Maybe they got a batch of cheap Chinese steel

 

[ezcome-ezgo]

Isn't this the seam on the inside of the kink?

 

[Functional Artist]

Here are the (2) roll bars

Here's how I did 'em

The plan

A piece of pipe

Markings, on the piece

In the bender

* This is after the very first bend
...& what (10) "pumps" (of the jack) looks like

This what it looks like after "executing" the plan

* The (10) pumps on all marks gave a nice-n-smooth curve
...& then (5) more pumps, on the middle "mark"
...brought the legs ta where they needed to be, at the bottom (~20")

 

[Functional Artist]

Isn't this the seam on the inside of the kink?

View attachment 160022

Hey Ez,
Yup
...but, I've been doing compound bends
...in this type of material for years
&
The orientation of the seams
...usually doesn't affect the bends

 

[ezcome-ezgo]

The orientation of the seams
...usually doesn't affect the bends

China got you now.

 

[Master Hack]

I needed to bend some 3/4 OD HREW, but I don't have a die for that. So a 1 inch die is purdy close, right? No, its not.
Attempt 1 kinked similar to your kinky bends.
Attempt 2 with nothing to lose, I filled the tubing with steel balls, duct taped the ends shut and was surprised when it actually worked. No kinky shyt here on the mountain top. Try sand??