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From: Amonchare <mak9@******.EDU>
Subject: adjustments to engine stats
Date: Fri, 12 Feb 93 12:48:11 EST
Well here I go again. This is the third time I have started this post. 1st I
was kicked off the system for no apparent reason. 2nd Someone switched the box
connecting me to the network. So needless to say I am not a happy camper. I
apologize in advance for any incomplete explainastions. And sorry for venting
here. I also apologize for copying most of Hayden's last post.

>>>>>>>From: R Andrew Hayden <rahayden@*****.WEEG.UIOWA.EDU>

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
I like the body and Weight coulmns put reserve judgement on the NPUs until we
have established more firmly other areas of design.

I want to build a Large car. [stuff deleted]
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


600 NPU Gas = 630,000<<<<<

OK, here's where my $0.02 start. I believe that we should measure power
"real" units of power such as watts. We can do this by simply changing our
"fudge fator" to .3 rather then 1.75. Therefore:

Gas Power (watts) = (NPU^2) * 0.3
and a 600 NPU engine would 108,000 watts (0 horsepower). typical for an
auto engine in 1993. (I know this may not be typical in 2054, but its a
reasonable place to start.)

>>>>>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?<<<<<

For this "fudge facto" (FF) I suggest .25 @ 600 NPU, power (elec)= 90,000
watts (0 hrp).

>>>>>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.<<<<

Because of the FF was change in the power eq. we need to add one here. It
looks like we needed one anyway with the high we were getting. Therefore I

Cruise speed = Power*2/weight
This gives a cruise speed of 72 kph for the 108,000 hrp engine and 60 kph for
the 90,000 hrp engine. Seems more reasonable to but its still higher than RBB.

>>>>>Redline Speed:

Two equations are being batted around:

RS = Cruising Speed * 2
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<<<<<

I'll only with the gas engine from now on. Redline speeds for the gas engine
would be 144 or 216 kph. Again more reasonable. I perfer the *3 version to
be able use RBB pre fab cars and our cars with the same set of rules (what
ever they may turn out to be).


The suggestion was:

Economy = Power / 2 (weight*eNPU)
or, for our car
Economy = 630,000 / 3,600,000
Economy = .175 km/unit<<<<

I purpose the following formula for economy:

Economy = (Cruising speed * 10,000) / power
67 km/l (41 mpg) for the car we are considering a little high for shadow run
standards but I think reasonable.

I do realize there may be problems with this formula because it does reduce to:

Economy = 20,000/ weight

If any one is interested in how I derived this equation please let me know.
Its derivation is more mathematically sound then the one for speed. ie. no
FF's. The 10,000 is a real conversion factor.

>>>>>[other FF examples deleted]

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<<<<

Good idea, I'll try a 400NPU engine with my equations

Power = 48,000 (64 hrp)
cruising = 32 kph (yuck)
Redline = 64 or 96
Well 400NPU is definently to small for my system. maybe it would work for a
motor cycle. Oh well it was my first attempt let me know what you think
meanwhile I'll keep working.


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