Sequoia Electrathon Racer

[Master Hack]

Surely you can find a helmet with a head up display?

 

[Denny]

Card board steering wheels generally don’t work too good, especially in the rain. I’m just sayin.

 

[Functional Artist]

Surely you can find a helmet with a head up display?

Hey T,
Seen 'em on TV
...but, never played with one

I just "got an idea"
...& already have the power meter
...& the phone/app speed-o
...plus, we gonna need a couple of switches too

 

[Functional Artist]

Card board steering wheels generally don’t work too good, especially in the rain. I’m just sayin.

Hey Denny,

It's made outta that extra-strength, Saw-Glu'ed, industrial cardboard
&
The windscreen will block the rain
...so, that shouldn't be a problem

 

[Functional Artist]

Been workin' on some pedals

...placment & mount for the Master Cylinder too

I think I can make a mounting bracket out one of the mis-bent spindle brackets that I made for the Polaris racer

Cut-out a hole

...& drilled some holes ta mount 'er up

 

[Denny]

Is Terry going to make the crank for the pedals too? Or are you just going to rob some kids Schwin?

 

[Master Hack]

Questions...
1. is there a bushing going through the "pipe" where the pedal bolts go through?
2. What is the diameter of the "pipe" and the " threaded thingy"
3. Why does that look like a piece of HREW tubing?
4. The pedal mounting sub-frame assembly is not structural is it?

I admire your ability to come up with clever solutions to making things.
My technique is look, cut, weld, scrap then repeat.
Nice work! Egor approves as well!

 

[Functional Artist]

Questions...
1. is there a bushing going through the "pipe" where the pedal bolts go through?
2. What is the diameter of the "pipe" and the " threaded thingy"
3. Why does that look like a piece of HREW tubing?
4. The pedal mounting sub-frame assembly is not structural is it?

I admire your ability to come up with clever solutions to making things.
My technique is look, cut, weld, scrap then repeat.
Nice work! Egor approves as well!

Hey T,

Thanks!
1.) no, just a 5/16" hole

2.) 7/8" OD (1/2" schedule 40) pipe

3.) IDK its just a piece of pipe "fresh off the rack"
4.) its not really meant ta be
...but, probably adds some strength/rigidity to the front of the chassis

* Notice these simple little pedals (~$7.00 ea.) https://www.bmikarts.com/Gas-Foot-Pedal_p_1155.html
...have a built-in "return stop"

...& (4) linkage connection holes

 

[Denny]

Well at least you did not make the mounting bracket for the mc out of cardboard. But I don’t get how the pedals are going to make it go without a crank?

 

[Master Hack]

Looks great! Just curious as to how you approached that. Nice pedals. I may have to quit being so cheap....
BTW, are you successful in de burring the spacers?

 

[Master Hack]

Iff'n ya wanted to git fancy, I think ya have some tubing with a 1" fish mouth on the end. it could be cut short and used here. Not necessary, probably a waste of time, but it might look mo cooler? Just another hack idea.

 

[Functional Artist]

Well at least you did not make the mounting bracket for the mc out of cardboard. But I don’t get how the pedals are going to make it go without a crank?

Hey Denny,

This "little guy" is gonna make 'er go

It's a Boma BM-1024GD
...60VDC
...2,000W (brushless) motor (max RPM rating of ~5,600)

Pic of specs

So, for discussion purposes, let's say it's "loaded" RPM is ~5,000 RPM's
...the Gear Ratio is 4.8:1
...the tires are ~51" in circumference

Ballpark Equation
MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier (.000189) = Miles Per Hour

5,000(RPM's) / 4.8(GR) = 1,041.67 (axle speed)
1,041.67 x 51 = 53,125.17 (inches per min traveled)
53,125.17 / 12 = 4,427.10 (feet per min traveled)
4,427.10 x 60 = 265,626 (feet per hour traveled)
265,626 x .000189 = 50.20 MPH

 

[Master Hack]

Ballpark Equation
MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier (.000189) = Miles Per Hour

5,000(RPM's) / 4.8(GR) = 1,041.67 (axle speed)
1,041.67 x 51 = 53,125.17 (inches per min traveled)
53,125.17 / 12 = 4,427.10 (feet per min traveled)
4,427.10 x 60 = 265,626 (feet per hour traveled)
265,626 x .000189 = 50.20 MPH

Dude! ya just gave a headache!

That's difficult. Stick to the easy sh**!

 

[Denny]

But why do you need pedals then? I don’t understand.

 

[Master Hack]

But why do you need pedals then? I don’t understand.

They work like onea dem stair stepper machines they got at the gym.
I saw one one time through the window.
There was this twenty two year old chi...

 

[Denny]

I want to hear about the 22 year old!

 

[Functional Artist]

Dude! ya just gave a headache!

That's difficult. Stick to the easy sh**!

Hey T,
The Ballpark equation is just somethin' I came up with years ago (before all of the "on line" calculators, that they have available now)
...ta get a rough estimate of what a "set up" may be able ta do
...but, doesn't factor in stuff like rolling resistance &/or wind resistance etc.

are you successful in de burring the spacers?

Yup, I found it easiest to ream 'em out with a round grinding stone, in the Dremel
...& then, use the sander, to clean up the sides

But why do you need pedals then? I don’t understand.

Hey Denny,
'cause no matter how loud I yell "Yah!"
...or "Giddy up"
...or "Wuo!", these racers just don't listen

I added some adjustment "slots" to the motor mounting plate
...'cause the rear wheel don't move

Then, used some 5/16" x 1" Carriage bolts

...to bolt the motor to the mount

...without needing to use a wrench on the bottom side

 

[nobled2]

Hey T,
The Ballpark equation is just somethin' I came up with years ago (before all of the "on line" calculators, that they have available now)
...ta get a rough estimate of what a "set up" may be able ta do
...but, doesn't factor in stuff like rolling resistance &/or wind resistance etc.

A heavier kart doesn't help. I tried to do a bunch of math when I inherited my school project but really never could make heads or tails out of those power curve charts.

I've gone down the "try it and see what happens" road to get speed and endurance.

 

[Functional Artist]

A heavier kart doesn't help. I tried to do a bunch of math when I inherited my school project but really never could make heads or tails out of those power curve charts.

I've gone down the "try it and see what happens" road to get speed and endurance.

Hey nobled2,

Yup, them motor performance charts give me "fits" too

The Ballpark Equation looks kinda complicated but, it's really pretty simple

First, you find your motor's rated speed
...& in this example the rated motor speed was 5,600 RPM's
...but, I reduced it to 5,000RPM's, to account for the "load" of moving the vehicle

Second important factor is the gear ratio your kart is running
...& in this example the motor (drive) sprocket is a 10 tooth
...& the wheel (driven) sprocket has 48 teeth
...which (48 divided by 10 = 4.8) gives us a 4.8:1 gear ratio
(which means that the motor turns 4.8 RPM's for every (1) RPM of the wheel)

Third important factor is the (circumference) distance around, the outside of, the (drive) tire

So, once you have those (3) factors, you just divide the motors RPM's by the gear ratio
...which gives you the axle/wheel speed (in RPM's or revolutions per minute)
5,000 (motor speed in RPM's) / 4.8 (Gear Ratio) = 1,041.67 (axle speed)

Then, multiply the axle/wheel speed, by the circumference of the wheel/tire
...which will tell you how far the wheel can travel in (1) minute (in inches)
1,041.67(as) x 51 (tc) = 53,125.17 (inches per min traveled)

Then, divide the inches traveled per minute by (12)
...which will tell you how far you traveled in (1) minute (in feet)
53,125.17 (IM) / 12 (FT)= 4,427.10 (feet per min traveled)

Then, multiply the feet traveled per minute by (60)
...which will tell you how far you traveled in (1) hour
4,427.10 (HR) x 60 (HR) = 265,626 (feet per hour traveled)

Then, multiply the feet traveled per hour by a MPH multiplier (.000189)
...which will tell you how many miles you can travel in an hour
265,626 (FH) x .000189 (MM) = 50.20 MPH

---------------------------------------------------------------------------------------------------------------------------------------------------------------
Ballpark Equation
MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier (.000189) = Miles Per Hour

5,000(RPM's) / 4.8(GR) = 1,041.67 (axle speed)
1,041.67 x 51 = 53,125.17 (inches per min traveled)
53,125.17 / 12 = 4,427.10 (feet per min traveled)
4,427.10 x 60 = 265,626 (feet per hour traveled)
265,626 x .000189 = 50.20 MPH

 

[nobled2]

I found this to be much easier:

Spicer Transmission Ratio RPM Calculator

Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.

spicerparts.com

put my 3.14 ratio sprocket set in there, 15.5 diameter rear tire, and 2000 rpm motor (24 amp) to get my theoretical top speed of 29.38.

Kart weighs in at 440# without driver and our ME0909 is doing all it can but we ain't getting to 29 mph