wombatone Seriously Crusin Dubber
167 posts · joined Aug 2002 ·
Has any one seen a program that can calculate the terminal velocity of a bug.
Terminal velocity calculator
hellbugged 48's and straight cuts
5,080 posts · joined Apr 2003 ·
ask dave- he knows things- aka "dangerous"
crewcabconnection Being Sid James
1,922 posts · joined Apr 2003 ·
what altitude will you be dropping it from?
Loves a lolcat
dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
The only formula I have is for terminal velocity in the standing 1/4 mile.
You will need engine power and your vehicle mass in lbs.
Answer will be in MPH.
Get the cubed root of (HP divided by weight), and then multiply your answer by 234.
So if your Volksy has a 60hp engine and weighs 1870lbs (850kgs)
=cubed root of (60 divided by 1870)
=cubed root of .0321
=.318
Then multiply by 234=74mph.
This will be a rude shock to all those people who think their engines make more power.
If you have a chassis dyno figure then you can add between 10 and 15 percent (depending on calibration and correction factors),
to get flywheel power to use in this formula.
[ Edited on 25-1-2006 by dangerous ]
You will need engine power and your vehicle mass in lbs.
Answer will be in MPH.
Get the cubed root of (HP divided by weight), and then multiply your answer by 234.
So if your Volksy has a 60hp engine and weighs 1870lbs (850kgs)
=cubed root of (60 divided by 1870)
=cubed root of .0321
=.318
Then multiply by 234=74mph.
This will be a rude shock to all those people who think their engines make more power.
If you have a chassis dyno figure then you can add between 10 and 15 percent (depending on calibration and correction factors),
to get flywheel power to use in this formula.
[ Edited on 25-1-2006 by dangerous ]
westi wrote:That's mad Alan.
lohoon Wolfsburg Wizard
466 posts · joined Sep 2002 ·
Isn't there a "table" that speed dudes use that considers final drive ratio + wheel diameter + top engine revs?
modulus Veteran Volks Folk
2,009 posts · joined Jul 2003 ·
Yes and no. What 'dangerous' is referring to above is a way of estimating trap speed at the end of 1/4 mile of full acceleration.lohoon wrote:Isn't there a "table" that speed dudes use that considers final drive ratio + wheel diameter + top engine revs?
Of course, the car may go on to achieve a higher top speed, which can be calculated from the top gear ratio, final drive ratio, top rpm, tyre size etc. *provided* that the horsepower curve of the engine is able at all points in the top gear rev range to deliver more kW than required by the sum of rolling resistance (usually small) and aerodynamic resistance (usually big).
I can't guess what wombat wants to know, so I'll go with:- if you drop it from a C4 transporter at 10,000 m, it should top out at about 180 kph before it hits the desert floor.
[ Edited on 25-1-06 by modulus ]
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dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
Gear ratios can be used to calculate theoretical top speeds but
unless the engine makes enough power to overcome the frictional losses
(air and other), then it is just theory.
A 60 hp vw beetle would probably max out at less than 90mph
.....well unless "gravity is your co-pilot"
unless the engine makes enough power to overcome the frictional losses
(air and other), then it is just theory.
A 60 hp vw beetle would probably max out at less than 90mph
.....well unless "gravity is your co-pilot"
westi wrote:That's mad Alan.
dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
Well said Peter, you beat me to it and described it better.
westi wrote:That's mad Alan.
VWCOOL 23 Windows of Awesome
5,158 posts · joined Jun 2003 ·
Yeah - it's called a speedo :P
Pay your debts, CxxT
speedster356 Plastic not Classic Racing
1,624 posts · joined Aug 2002 ·
If your looking for theoretical top then the final drive, tire size, and max engine revs are used. I have a formula some place that then uses your theoretical top speed along with Cd, and frontal area and gives you the required HP to reach that top speed. This dosen't take into account rolling resistance (tire on surface) but is used by the salt lake speed guys. Remember that drag squares by the velocity....:o
Spyder-WISD 07-09-05 11.6s @ 125 MPH
Speedster-WISD Nats 05 14.4s @ 89 MPH
Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm
Weaseling out of things is what separates us from the animals....................Except the Weasel.
Speedster-WISD Nats 05 14.4s @ 89 MPH
Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm
Weaseling out of things is what separates us from the animals....................Except the Weasel.