| From: | R Andrew Hayden <rahayden@*****.WEEG.UIOWA.EDU> |
|---|---|
| Subject: | Ok, here's what I've got |
| Date: | Fri, 12 Feb 93 06:26:49 CET |
getting close to workable equations, really close. We might even
be done with this part soon.
-----------------------------------------------------------
Car Chassis:
Name Weight (in kg) NPUs Body
-----------------------------------------------------------------
Mini 400 800 1
Small 700 1400 1
Medium 1000 2000 2
Large 1400 2800 3
X-Large 1900 3800 4
% % % % %
Ok, lets build a car and I'll see what my calculator comes up with
for numbers.
I want to build a Large car. I've got 1000kg worth of stuff to
put in it (ranging from a giant 300mm rapid-firing recoilless
heat-seeking munchkin Bazooka, to my 9 foot tall Troll girlfriend)
Total weight without the engine is 2400kg.
Of the 2800 NPUs, I've allocated 800 to engine. Since I've got to
have some space for fuel and whatever engine accessories I add,
lets put in a 600 MPU engine.
Lets figure out our engine power. I'm going to Carter's equations:
Gas Power = (NPU^2) * 1.75
Elec Power = NPU^2
so
600 NPU Gas = 630,000
600 NPU Elec= 360,000
First thing I see is that electric is too wimpy. You are talking
about electric being about .5x as powerful per NPU as a gas
engine. I don't thing this is right. Perhaps use (NPU^2) * 1.25
for electric power?
In any case, I want to put in a gas engine (my troll girlfriend
loves loves the smell of gasoline). That gives us 630,000 power
units. An engine of this size also increases our total car to a
weight of 3000kg.
-------------------
Next we'll figure out our cruising speed. The formula that seemed
to agreed upon is:
Cruise Speed = Power / Weight
This will give us a cruising speed of 210 km/hour. That means this
car can hit around 130mph without breaking a sweat.
Perhaps it is just me, but I think we are a little fast. Lets see
what else happens later on
--------------------
Redline Speed:
Two equations are being batted around:
RS = Cruising Speed * 2
or
RS = Cruising Speed * 3
This would yield 420 and 630 respectively. Ie, you redline at
about 260mph, which is faster than most Indy cars. OOPS
----------------------
Anyways, lets keep going, we're on a roll.
Economy:
The suggestion was:
Economy = Power / 2 (weight*eNPU)
or, for our car
Economy = 630,000 / 3,600,000
Economy = .175 km/unit
Seems kinda guzzly, don't ya think :)
------------------------
Oh boy, how to sum up. We need some more work, obviously,
especially on the economy question.
As a test, I'm going to run the same calculations with a power
equation of: P = (eNPU^2) * 1.5
Power = 540,000
Cruising= 180 km/h (about 112 mph . . . still too high)
Redline= 360 or 540
And now the same with a 1.25 multiplier
Power = 450,000
Cruising = 150 km/h (about 90mph or so . . . much better)
Redline = 300 or 450
Now, with equations like this, it would seem that a 600npu engine
is overpowering the car (based on speed). Just for kicks, I'll
compute the above with a 400npu engine and the 1.25 multiplier (but
still a 3000kg vehicle)
Power = 200,000
Cruising= 66 km/h (a mere ~40mph)
Redline = 132 or 198
This would be an example of a fairly underpowered "Large" car.
Great for toodling around town, but a piece of crap on the highway.
-------------------
In any case, we still need more work it seems. Any more thoughts?
I think we can use a 1.25 multiplier for gas, and a 1.00
multiplier for electric and get workable power results, but some
more testing is required, too.
[> Robert Hayden <] [> ____ Come out, Come out <]
[> <] [> \ /__ Wherever you are! <]
[> rahayden@*****.weeg.uiowa.edu <] [> \/ /
[> aq650@****.INS.CWRU.Edu <] [> \/
