Diamonite Electrathon America Racer

[Master Hack]

This is the upgrade you need!

1.4M views · 36K reactions | World’s fastest bathtub 😂? Sure sounds mean and throws a sick drift 🤟🏼 #bathtub #fastbathtub #drifting #driftingbathtub #yamahar6 | Biltuben

World’s fastest bathtub 😂? Sure sounds mean and throws a sick drift 🤟🏼 #bathtub #fastbathtub #drifting #driftingbathtub #yamahar6.

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[Denny]

It looks like you are trying to build a Chevy Monte Carlo front end.

 

[Functional Artist]

It looks like you are trying to build a Chevy Monte Carlo front end.

Hey Denny,

Yup!
...late '80's Monte Carlo

Winner, winner...turkey dinner

Been admirin', thinkin' about & studdin' on 'em for a while
...then, while doin' research on workin' with fiberglass, I came across some videos on "plug" makin'
...& before I knew it...my left brain wasa "hummin'" away

I quickly found/noticed/learned that unless you/me/we want just a "plain Jane" smooth face
...& then just add some stickers
...it gets kinda complicated

Because not only does the top angle slightly, upwards as it goes towards the windshield
...it also angles upward from each side
...& then, comes to a "peak" in the middle

To, help "get a grip" of ALL of the multiple angles, I started playin' with soam foam

To help keep the math kinda simple, I'm using a 36" wide "track" width
...so, I cut 36 pieces of 1" foam
...stacked 'em together, kinda like books
...& then, trimmed 'em 1 by 1, makin' them successively bigger
...until we had a "peak" on the top
...& a "point" in the front

Side view

Front view

The front (head light/grille area) angles back a bit, toward the rear
...& also, comes to a "point" in the middle too

Lots of smoothin' & shapin' ta do
...but, it's startin' ta take shape

 

[Functional Artist]

The way cars are built is a skeleton frame with chassis mounting points then skinned over with fiberglass. To make the fiberglass strong enough to support a suspension it would end up being thick and heavy to be strong enough. I’m thinking more 60/40-50/50.

Hey Denny,

Still in the design stage
...& probably will be for a while
...but, just exploring some of the potential options (ain't this fun?)

Like going with a "straight axle"
...well...not really straight
...actually kinda curvy
...but, all (1) piece

Where the front of the fiberglass chassis
...would be completely supported
...by "sitting on top" of a (1) piece straight axle

One of the interesting features, that I'm learning about, working with composite/fiberglass design/construction is that the chassis can be "beefed up" in critical places, without adding a bunch of unnecessary bulk/weight...everywhere else

To "take it a step further" another interesting "tid bit" I just found out about &/or was brought to my attention (while reading a book)
...was that "doubling the depth, leaving all other dimensions the same, makes the wing 8 times stiffer"

I'm thinkin' that this concept should probably be consistent with...well...most anything & everything
...like some of those "critical" suspension mounting point areas, in a composite chassis

So, much to learn
...& havin' so much fun, doin' it

 

[Functional Artist]

This thing will float, I just know it will. I believe.

Hey Ez,

Yup, it has some "boat like" characteristics
...good eye!

I'm finding out that aerodynamics (going thru air) & fluid dynamics (going thru water) have a lot of characteristics in common
...& so, a shape that will "glide" thru water easily, should/will also, "glide" thru air easier too

I've been researching about boat building
...& aircraft design/construction
...& even reading a/some books (actually re-reading this one)

...& takin' lots of notes too

 

[Denny]

GM used a lot of flowing water models to design cars back in the early 30s. Way before wind tunnels were used for cars. They made a constantly flowing miniature river put a shape in it and then added aluminum powder to see how the water flowed around the object.

 

[ezcome-ezgo]

Then they had a cocktail and a cigarette, leered at the secretaries for a while, went home and spanked their kids, got up the next day and started all over.

 

[Master Hack]

GM used a lot of flowing water models

Is that were they got the idea to build land yachts?

 

[Denny]

Then they had a cocktail and a cigarette, leered at the secretaries for a while, went home and spanked their kids, got up the next day and started all over.

They did the secretaries. Get it right.

Is that were they got the idea to build land yachts?

No, they stole that idea from Chrysler and ferd.

 

[Functional Artist]

I've been reading the Composite Construction for homebuilt aircraft book (twice)
...then, went thru it again & took some notes & pics
...& now I'ma gonna share some info with you'all
...or spill the tea, as my daughter would say

"doubling the depth, leaving all other dimensions the same, makes the wing 8 times stiffer"

So, first, to expand on this topic a bit more

See pic below (page 48 in the book)

1.) First image just shows (4) layers of fiberglass

2.) Second image shows the same (4) layers of fiberglass
...it's just (2) layers of fiberglass
...separated by a foam core (same thickness as the (4) layers of fiberglass)
...& then, (2) more layers of fiberglass

So, now the piece is (2x) thicker
...but, (7x) stiffer
...& (3 1/2x) stronger
...while only being ~3% heavier

3.) Third image shows the same (4) layers of fiberglass
...just with (2) layers of fiberglass
...& a double thick (2x) foam core (same thickness as the (8) layers of fiberglass)
...& then, (2) layers of fiberglass

So, now the piece is (4x) thicker
...but, (37x) stiffer
...& (10x) stronger
...while only being ~6% heavier

So, (currently) I'ma thinkin' maybe try building a "body" with (3) layers of fiberglass (woven, strand, woven)
...then, a 1/4" foam core
...& then, another (3) layers of fiberglass (woven, strand, woven) on top of that

Seems like it should be ~1/2" thick (overall)
...& "super strong"
...& then, I'll "beef" 'er up a bit more, in other critical areas

 

[Denny]

I still say you need steel attachment points for the suspension.

 

[Master Hack]

I still say you need steel attachment points for the suspension.

Agreed! 'glass won't hold up to the stresses, unless it's really really thick ands solid. Mo bedder yet is a steel sub frame with all the propulsion equipment securely attached to that. That could even be incorporated into the 'glass body. "glass is a mess to work with, for me at least.

 

[ezcome-ezgo]

Is this along the lines of what you are thinking?

 

[Functional Artist]

Yup! you got the basic idea
...but, I'ma tryin' ta keep er kinda simple(er)
...by not having complicated or heavy metal frame sections, connected to the ends of the chassis

To keep the wheelbase kinda short (for better maneuverability) I'ma thinkin ta have the front axle
...or A-frames, mounted a bit further back (like in this pic)

In the rear I'ma thinkin' about just connecting a trailing arm to a re-enforced, bottom rear of the fiberglass chassis
...the base of the roll bar should be incorporated into this connection/joint too
...& then, supported by a (or pair of) coil-over shocks (kinda like on my Mini-slingshot)

 

[bob58o]

Cool beans. Not sure if you follow the Cletus McFarlen YouTube Channel but they just had a body built for Leroy the Vette Kart. They removed all body panels along time ago. Recently they did the foam / fiberglass thing to create a body. First couple passes, I think the wind forces tore off the widows and/or doors. After a bit of reinforcing and repair, it made its fastest passes.

This pic shows an early iteration when trying to make it look like a bald Eagle.

 

[Denny]

Bald eagles infact don’t have any hair.

 

[Functional Artist]

I still say you need steel attachment points for the suspension.

Agreed! 'glass won't hold up to the stresses, unless it's really really thick ands solid. Mo bedder yet is a steel sub frame with all the propulsion equipment securely attached to that. That could even be incorporated into the 'glass body. "glass is a mess to work with, for me at least.

Hey fellas,

I agree
...with metal (steel or aluminum) attachment points
...& 'glass (by itself) won't hold up to the stress

So, lets "dive" (airplane &/or boat reference ) into this a bit more

* First, I'm not an expert
...so, this is what I "think"
...or "think" I know
...or at least, seems to "make sense" (to me, anyways)

So, think about a sheet of notebook paper
...if you grab it on each side & try to pull, it's very strong (in tension)
...but, if you grab it on each side & try to push together, it's not nearly as strong (in compression) & bends/buckles & folds easily
...& if (held in tension) & then, pressure is applied from the side (side load) you may be able to "poke" right thru

Next, think of a similar size piece of cardboard
...basically, the same materials as paper (wood fibers/pulp & glue, formed into a sheet)
...so, it has similar characteristics/properties
...but, because its thicker, its stiffer & stronger
...&/so, the tension strength, the compression strength & the side strength have all been increased
* Kinda follows the concept mentioned in post #70 "(2x) thicker = (7x) stiffer & (3 1/2x) stronger"

Now, let's move on to fiberglass
...which is just glass fibers & super strong glue
...& similar to paper & cardboard, it is strong in tension (but, because of the "base" materials, tremendously stronger)
...&/also, similarly it's not as strong on compression or "side loads" (but, still tremendously stronger, because of the "base" materials)

So now, for simplicity, let's say we have a monocoque made out of cardboard
...& to make it even simpler, let's say we connect the A-frame rods directly to the sides of the chassis (called "point loads")

Now, let's say the diameter of the nuts connecting the A-frame rod to the chassis was 1" (for simple math)

It should be pretty easy to "see" how the end of the A-frame rod (with only a 1" dia.) could be "punched" thru the side of the chassis
...now, let's say we insert 2" washers, under the 1" nuts & "see" how we "spread" the load out (x2)
...&/so, the bigger the "washer" the less(er) the "point load" on the panel

* Even bigger "washer" = correspondingly less(er) "point load"

& then,
If the "washer" or plate is actually fastened/bolted to the panel
...it stiffens & strengthens the area
...& "spreads" the load out, even better
&
If another "washer" or plate, is used on the inside (sandwiching the fiberglass in between)
...& then, the (2) "washers" or plates, are thru bolted together
...it stiffens & strengthens the area, even more
...& also, would "spread" the load out, even better

The same concept would apply to the (upper) shock mounting area too
...except this "mount" is more in the middle of the panel
(whereas the lower A-frame connections are near the junction with the floorboard &/so, has some "built in" structural support)

So, this mount would probably need some additional structural support
...& there are many options/ways available to do this ('which is a whole 'nuther "story" that we'll get into shortly)

 

[Denny]

But fiberglass does not like to be crushed. Wood/paper does much better in that aspect. Just like a window glass if you crush it the fibers shatter. One has only to look at corvette construction to see the built in steel (now aluminum) birdcage to know you need a light steel structure to build from.

 

[Functional Artist]

But fiberglass does not like to be crushed. Wood/paper does much better in that aspect. Just like a window glass if you crush it the fibers shatter. One has only to look at corvette construction to see the built in steel (now aluminum) birdcage to know you need a light steel structure to build from.

Hey Denny,

"glass don't like to be crushed...or it shatters" ...make total sense
...but, I haven't came across any kind of mention, notice or warnings about...not doing it

I did find this in the Composite Construction for Homebuilt Aircraft book (page 182.)

"Standard fiberglass cloth is exactly what the name says-glass. Fine fibers are spun from molten glass marbles, gathered into yarn & woven into a strong, supple glass fabric. It can be folded, rolled or draped, like any other loosely woven fabric - but it can be chemically transformed into solid sheets of tremendous strength."

So, could the "chemically transformed" aspect, change anything?
...like...'cause the glass fibers are "locked' in layers of cured Epoxy/resin?

In another book I read recently, Composite Aircraft Design (by Martin Hollman)
...they show a building concept where they use wood stringers over plywood bulkheads

Then, foam is glued on
...shaped & smoothed
...& then, covered with a layer of fiberglass

Since the base structure is wood
...most of the body is not really critically stressed
...&/so, they usually only apply (1) layer of fiberglass
...because it's just a "shell"

But, that's just another version of a fiberglass body, on a skeleton or frame
...& that's NOT what I'ma tryin' ta do here

I'm wantin' ta explore some of the possibilities of composite frameless construction
...for a really lightweight (hopefully under 300 lbs.)
...& relatively low speed vehicle (under 30 MPH)

Check out this chart I came across (in Composite Construction for Homebuilt Aircraft on page 12.)

* Notice the HUGE difference in physical properties between Aluminum, steel & fiberglass
Aluminum 30,000 Tensile (PSI) & 10,000 Compressive (PSI)
Steel 95,000 Tensile (PSI) & 28,000 Compressive (PSI)
Fiberglass 500,000 Tensile (PSI) & 62,000 Compressive (PSI)

I always say, there's strength in design
...& strength in materials
&
I think (we) can come up with some really strong designs
...that work with & enhance these really strong materials
...without the need for re-enforcement from a metal frame

 

[Master Hack]

Having had a few 'glass boats, l learned glass is tough. It'll take a lot to break it, but keep in mind, it flexes. When it breaks it splinters and leaves sharp edges.
Done right it'll be plenty strong for a vehicle of this weight. The key is laminations and reinforced attachment points. The only problen spots i encountered with boats
(, other than crashing into imovable objects) where bolts were run through glass without any help. Vibration, and stress will take a toll. It burns also, Acrid, toxic black smoke!