Author Topic: Simspeed UWD LSR Design Project  (Read 89910 times)

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Offline Eddieschopshop

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Re: Simspeed UWD LSR Design Project
« Reply #135 on: August 07, 2019, 12:45:17 AM »
That 2400 for the summer brothers really reinforces my point.  The drag to hp calculator is a very small part of the total equation in making a car that works.  Look at target 550 or should I say project 350?  There is more to racing than the numbers will have you believe

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #136 on: August 07, 2019, 01:21:27 AM »
Simspeed .. My bville pro is not responding to streamliner data? Says inputs out of parameters?

 I have a Bville book with all the info on Summers Bros. Goldenrod but have been to busy with the 222 Camaro to look for it, From what I remember weight and hp were about the same as yours and I don't
remember the CD or frontal area but I know it was pretty good.

 i need to buy another program too as it's not transferable to my newer laptop.

    JL222
Uh Oh...wished I'd known that before ordering a copy for myself.  Paid for it but not yet delivered.  No refunds he says.  Oh well...we'll see what happens.  Good luck with the 222 JL.  Thanks... Terry

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #137 on: August 07, 2019, 01:26:47 AM »
That 2400 for the summer brothers really reinforces my point.  The drag to hp calculator is a very small part of the total equation in making a car that works.  Look at target 550 or should I say project 350?  There is more to racing than the numbers will have you believe

No doubt Eddie.  I'm just looking for a baseline as compared to real world times/numbers from competitors like you and others.  More than likely this project will never see the salt but we have to start somewhere and see what develops.  I'd  like to know if the combination as shown could be competitive if everything came together as envisioned.  Thanks... Terry.

Offline desotoman

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Re: Simspeed UWD LSR Design Project
« Reply #138 on: August 07, 2019, 01:30:09 PM »
Look at target 550 or should I say project 350?  There is more to racing than the numbers will have you believe

Eddie,

Target 550 has gone 385 plus at Bonneville (that is what the timing slip says) with soft tuneup, on terrible wet salt, in and out of the throttle, in testing.

I don't think the "project 350" comment was necessary.

Tom G.
I love the USA. How much longer will we be a free nation?

Asking questions is one's only way of getting answers.

The rational person lets verified facts form or modify his opinion.  The ideologue ignores verified facts which don't fit his preconceived opinions.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #139 on: August 08, 2019, 12:40:37 PM »
I finally received the email to download the Bonneville Pro software and as JL222 stated it would not give results based on inputs for the Simspeed vehicle design.  Not only would it not allow the user to input actual horsepower and torque figures (it used some predetermined formula to calculate torque or hp depending in what was input first..?? Dumb), it also used a fixed range of some unknown index value for drive line slippage tied to engine rpm that made no sense to the user.  An "out of range" warning message was shown that stated the value was both too low and two high simultaneously but would not allow adjustments outside of the range...??  Gear ratios and rpm for each gear didn't apply because the project design calls for direct drive through the electric motors with an effective 1:1 final drive.  The program apparently doesn't allow direct drive scenarios.  Overall it was a complete waste of money with virtually no support or refunds.  Oh well...live and learn... Terry

Offline ggl205

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Re: Simspeed UWD LSR Design Project
« Reply #140 on: August 08, 2019, 01:05:53 PM »
At least for me, GearSplit was a much more accurate and reliable software to determine gearing, time/distance/speed and tire size for LSR cars. No limits either. Only downside is it has not been updated to run on a modern OS. Win XP is it so if you have an old computer, you are in luck. Also, the developer, Dave Dahlgren, has not sold a copy in a while. Worth contacting him, however.

John
« Last Edit: August 08, 2019, 01:08:27 PM by ggl205 »

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #141 on: August 08, 2019, 06:39:09 PM »
At least for me, GearSplit was a much more accurate and reliable software to determine gearing, time/distance/speed and tire size for LSR cars. No limits either. Only downside is it has not been updated to run on a modern OS. Win XP is it so if you have an old computer, you are in luck. Also, the developer, Dave Dahlgren, has not sold a copy in a while. Worth contacting him, however.

John
Thanks John...I think I'll just research the formulas and build my own spreadsheet and see what I come up with.  Thanks again... Terry.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #142 on: August 08, 2019, 11:53:01 PM »
After a few hours of research I found all the formulas required to accurately calculate drag, rolling resistance, and horsepower for a given speed.  Bonneville air density was gathered from today's weather reports and I used constants for converting metric values to U.S. standards.  So the results satisfy what we were hoping to learn.

Unfortunately, the needed horsepower exceeds what we planned for based on other hp spreadsheets we used at the beginning of this project.  Attached are three calculations for 400, 500, and 600 mph target goals.  460 mph is about the best we could hope to obtain with the current gen/motors.  The rotary IC engine output is good for 500 mph, but we'd either need more gen/motors or more powerful gen/motor specs to utilize that power.  We're going to need more than 3000 total hp from our IC/Gen/Motor package to have a chance at 600 mph with the current body geometry. 

We'll see what a third IC/Gen power plant and two more drive wheels look like in the next V.5.5 design.  Thanks... Terry


Offline STICK777

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Re: Simspeed UWD LSR Design Project
« Reply #143 on: August 09, 2019, 02:58:46 AM »
As it stands at the moment even 2500HP would be enough to put you in the history books as the first reaching, err  510+mph:wink:
So go for it!   :cheers:

PS. We'll see what Speedweek will bring...
« Last Edit: August 10, 2019, 04:44:13 AM by STICK777 »

Offline salt27

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Re: Simspeed UWD LSR Design Project
« Reply #144 on: August 09, 2019, 11:31:10 AM »
As it stands at the moment even 2500HP would be enough to put you in the history books as the first reaching 500+mph.  :wink:
So go for it!   :cheers:

PS. We'll see what Speedweek will bring...

The wheel driven 500 mph mark has already been breeched, Turbonator II (503.332 mph) terminal speed.    :cheers:

« Last Edit: August 09, 2019, 11:35:52 AM by salt27 »

Offline ggl205

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Re: Simspeed UWD LSR Design Project
« Reply #145 on: August 09, 2019, 12:02:34 PM »
The wheel driven 500 mph mark has already been breeched, Turbonator II (503.332 mph) terminal speed.

But a record at or over 500 mph has not.

John

Offline STICK777

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Re: Simspeed UWD LSR Design Project
« Reply #146 on: August 09, 2019, 01:19:32 PM »
As ggl says... breaching is not enough. Terminal speed is not a record.
Turbinator probably has more than 2500HP in its turbine, so we'll see whether they can go for the record.

Offline salt27

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Re: Simspeed UWD LSR Design Project
« Reply #147 on: August 09, 2019, 04:13:29 PM »
I am quite aware that the Turbinator II has not set a record of 500+ yet.

I was responding to Stick saying "the first reaching 500+ mph", which they did.

Sorry for any confusion, carry on.

  Don


Offline tortoise

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Re: Simspeed UWD LSR Design Project
« Reply #148 on: August 09, 2019, 09:37:27 PM »
After a few hours of research I found all the formulas required to accurately calculate drag, rolling resistance, and horsepower for a given speed.
Your charts show the same rolling resistance at all speeds, a force much higher than the air resistance. I had understood that rolling resistance went up more or less linearly with speed, and that at high speeds it was relatively much smaller than aero drag. What's going on here?

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #149 on: August 10, 2019, 08:42:46 AM »
After a few hours of research I found all the formulas required to accurately calculate drag, rolling resistance, and horsepower for a given speed.
Your charts show the same rolling resistance at all speeds, a force much higher than the air resistance. I had understood that rolling resistance went up more or less linearly with speed, and that at high speeds it was relatively much smaller than aero drag. What's going on here?
Hi Tortoise,
There's a "LOT" of debate on the effects or no effect of speed on rolling resistance values.  The power formula I'm using here does factor Cr coefficient into account where speed is a calculated input to find power required to overcome aero drag and rolling resistance drag.  The line item values for Rolling resistance and Body Drag are fixed values using what I found to be the stand alone RR formula F = Cr x W; (Force= RR coefficient x Weight) where speed isn't factored.  The numbers don't change because in all three examples the Cr and W don't change.  So effectively the line items don't factor speed into the posted results but the power equation does.

I found numerous definitions of RR formulas that claim speed is irrelevant as velocity increases, but I chose the formulation where speed is factored.  The Cr value of 0.039 I'm using here is said to be representative of the Cf (coefficient of friction) for hard packed sand at high speed which is the closest example to salt that I could find.  I did find agreement with your statement that RR is more or less consistent with the linear increase in speed where aero resistance rises exponentially with the same increase in speed.  Yes...somewhat confusing I admit but its apparently a very complicated subject.  Thanks... Terry.