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Search: Posts Made By: kennybobby
Forum: Aerodynamics 01-08-2018, 11:51 AM
Replies: 2
Views: 810
Posted By kennybobby
Cd estimate for open-wheel dragster?

i was searching for an expected drag coeff for the typical open-wheeled style dragster such as shown here, has anyone seen measured or calculated Cd for this? Body panels would obviously be added,...
Forum: EcoModding Central 04-08-2014, 06:20 AM
Replies: 32
Views: 5,783
Posted By kennybobby
The King Venturi is Dead--Long live the Venturi!

If you are an electrical guy, then EFI appeals to your sense of simplicity and logic as a good solution that is easy to control.

If you are a mechanical guy, then carburetors appeal to your sense...
Forum: Hybrids 03-08-2014, 07:21 AM
Replies: 39
Views: 5,194
Posted By kennybobby
what are your units of charge value?

It looks like subpack #3 is bad by your data--all the rest settled down to 8.1-8.2 except that one dropped to 7.5, it's not holding.

i have done cell capacity checks on some batteries, the largest...
Forum: EcoModding Central 02-16-2014, 10:42 AM
Replies: 34
Views: 7,604
Posted By kennybobby
i have a problem with their conclusion #2, that...

i have a problem with their conclusion #2, that ethanol E20 produced higher torque at all speeds,etc. This statement makes me think that they don't know how an eddy current dyno operates or how to...
Forum: Aerodynamics 10-20-2013, 12:44 PM
Replies: 28
Views: 5,801
Posted By kennybobby
It takes 2.5 to 3 hp to go 100mph at sea level...

It takes 2.5 to 3 hp to go 100mph at sea level for a 180 to 200lb, .0005 crr, .10 to .11 cd, 3.5 to 4 sf vehicle.

Going up to 4500 ft drops the air density such that they were able to reach 83mph...
Forum: Aerodynamics 10-19-2013, 11:35 AM
Replies: 28
Views: 5,801
Posted By kennybobby
Looks like they used the template but are running...

Looks like they used the template but are running it backwards? They mentioned having an aerodynamic issue which prevented reaching the calculated top speed.

Human Power Team Delft & Amsterdam...
Forum: EcoModding Central 10-15-2013, 10:50 AM
Replies: 16
Views: 3,854
Posted By kennybobby
Nice looking wheels

Forged aluminum wheels can have the same strength as steel with less weight, which is very interesting albeit expensive. How much weight will you save?

The total weight of the vehicle is the...
Forum: General Efficiency Discussion 01-03-2013, 10:35 AM
Replies: 6
Views: 1,394
Posted By kennybobby
The speed of optimal efficiency is usually at the...

The speed of optimal efficiency is usually at the rpm of the torque peak, this occurs because the airflow in the intake is at maximum volumetric efficiency at filling the charge into the cylinder.
Forum: Aerodynamics 01-02-2013, 11:06 AM
Replies: 6
Views: 4,851
Posted By kennybobby
Ryan et al, You guys do know that the...

Ryan et al,

You guys do know that the pressure reported from the weather channel, etc, is not the real pressure right? They report the altimeter reading pressure at the nearest airport, which is...
Forum: DIY / How-to 12-18-2012, 09:08 AM
Replies: 17
Views: 3,993
Posted By kennybobby
Don't use spade lugs...

To do it right you will want to wrap the wire around the terminals and solder them, then cover with heat shrink tubing. They are rated at 50 amps average and 400 A peak. A sliding electrical...
Forum: Open ReVolt: open source DC motor controller 12-11-2012, 09:57 AM
Replies: 7,381
Views: 2,402,878
Posted By kennybobby
What version is your controller?

It looks like the motor bus bar is shorted to the heat sink.

If you wired up your controller using the 500Amp cougar mosfet schematic rev 2D that is found on the wiki page--it has a serious...
Forum: EcoModding Central 11-25-2012, 10:53 AM
Replies: 20
Views: 5,285
Posted By kennybobby
Many thanks for that find. Here are some...

Many thanks for that find. Here are some observations that i lifted from the report:

"Rolling resistance is due to hysteresis, which is a function of tire chararacteristics such as dimensions,...
Forum: Fossil Fuel Free 10-23-2012, 03:09 PM
Replies: 10
Views: 3,855
Posted By kennybobby
See if you can contact this guy--he's using one...

See if you can contact this guy--he's using one like yours and may know all about it...

http://www.youtube.com/watch?v=xr1j0bq_fA8
Forum: Fossil Fuel Free 10-20-2012, 12:14 AM
Replies: 10
Views: 3,855
Posted By kennybobby
Oh yeah i see that i did make a big...

Oh yeah i see that i did make a big assumption---that it actually was a motor! lol

A generator will make a lousy motor--it may seem to run like a motor when you connect the power, but just...
Forum: Fossil Fuel Free 10-18-2012, 07:09 AM
Replies: 10
Views: 3,855
Posted By kennybobby
Does it say if the 21 Hp is a continuous rating...

Does it say if the 21 Hp is a continuous rating or for just a limited duration?

let's assume it is continuous. 21 Hp is about 15,700 watts, so the 120 VDC rating let's us calculate the current...
Forum: EcoModding Central 10-12-2012, 07:53 AM
Replies: 70
Views: 45,264
Posted By kennybobby
What drugs are you guys taking?--Weight is not your friend

How much does all your modifications weigh? The Battery pack, battery box, solar panel, charge controller, etc.

Extra weight increases rolling resistance which is the dominant power loss at...
Forum: General Efficiency Discussion 10-11-2012, 06:59 AM
Replies: 6
Views: 1,833
Posted By kennybobby
Are you just baiting?

Lots of EV folks use these sort of prismatic cells, e.g. 3.2 volts, 180 AHr capacity

http://www.electricmotorsport.com/store/images/batteries_WIN_cell_variety.jpg
Forum: Hypermiling / EcoDriver's Ed 10-07-2012, 11:32 PM
Replies: 40
Views: 10,676
Posted By kennybobby
For a motorcycle yes, but not for cages...

Your understanding of an alternator is correct for a permanent magnet alternator such as is used on motorsickles--they run all the time and dump excess current back into heat. But we are only...
Forum: Hypermiling / EcoDriver's Ed 10-02-2012, 10:22 PM
Replies: 40
Views: 10,676
Posted By kennybobby
But it is the point of highest efficiency...

i think you answered your own question.

The peak torque that an engine generates does occur at the point of highest volumetric efficiency--when the airflow has the least restriction and the most...
Forum: General Efficiency Discussion 09-12-2012, 10:53 PM
Replies: 302
Views: 365,613
Posted By kennybobby
JHC, i just read thru 22 pages, 216 posts. ...

JHC, i just read thru 22 pages, 216 posts. Unfortunately the Signal to Noise ratio was very low.

It would be nice if the first post contained the link to the wiki page that actually has all the...
Forum: Aerodynamics 08-08-2012, 11:35 AM
Replies: 7
Views: 10,182
Posted By kennybobby
slight correction

Should be: 1 hp is 550-pounds, one foot, in one second.
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