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Author Topic: Simspeed UWD LSR Design Project  (Read 19072 times)

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Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #150 on: August 10, 2019, 08:45:13 AM »
In V.5.5 we've increased Gen/Motors to 12 each for a total of 2400 kW (3200 hp) and upped the power output of each of the 8 IC rotors from a conservative 300 hp each to a doable 400 hp with NO2 for a total of 3200 IC hp.  By stacking 3 generators to each 2 rotor power module we match total kW to IC hp capability (804.6 to 800).  We still needed to add 4 additional drive motors (2 wheels) to the drive train for a total of 6 wheels.  These fit nicely within the existing body and increased the overall length by a little over 2 ft.  All 6 wheels are spaced differently within the chassis so none track directly behind any other.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #151 on: August 10, 2019, 08:49:44 AM »
We rearranged the powerplants moving the rear engine, fuel, and oil tanks forward and the NO2 bottles rearward for a better Cg.  The aero wing moved forward too and the hydraulic cylinder for the wing was positioned vertically to allow for better spacing and operability.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #152 on: August 10, 2019, 08:54:19 AM »
We replaced the outrigger shoe for a half sphere that spins about the centerline of the extendable shaft.  This presents a more stable contact point for the outrigger in the event of a roll condition at slow speed.  Once the car is in stabilized motion the outriggers will be retracted by the driver.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #153 on: August 10, 2019, 09:02:32 AM »
This addition is probably controversial but we think it's a good application to help keep the vehicle upright due to the very narrow track width (12.8") at the front tires.  We believe these changes in hp and added traction from 6 driving wheels put us back on track for record setting potential.  To the best of our knowledge this design has the lowest aero drag with sufficient power of any unlimited wheel driven vehicle.  Thanks... Terry   

Offline GW

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Re: Simspeed UWD LSR Design Project
« Reply #154 on: August 10, 2019, 09:55:44 AM »
So many updates in so little time doesn't allow me to keep up.

1. I recall a while back the DIF debate; with the DIF as shown, how did that debate resolve itself with the recommendations to not do so?
2. FWIW, and with no facts or data, I recommend the outrigger shoe as to what appears would be a point load from a hemispherical contact point.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #155 on: August 13, 2019, 04:07:07 PM »
Hi GW,
Thanks for your comments.  My thinking on the ball shoe is that it will will rotate like a small wheel presenting a uniform contact point that has no sharp edge to dig into the salt.  The skid shoe as drawn could roll under and cause a sharp point contact at the end of the shaft that would dig into the salt and pivot the car destructively.  I don't think the ball shoe would do that but I could be wrong.  I guess it depends largely on how high the shoe is off the salt surface when fully extended.  The closer to the surface the more the ball shoe would act like a wheel limiting vertical angular movement of the body.  As with everything I present with these drawings I'm looking for critiques from members like you to help me think through things to hopefully arrive at practical solutions.

The DIF debate isn't over at this point.  The recommendations to not use a DIF layout are warranted as I agree there will be less mechanical feedback to the driver over a DIM or DIR position.  However, there was confirmation from Sparky that in his experience a yaw string works in providing useful feedback of the car's movement relative to cues the horizon presents at speed. So far no one has commented to the contrary. 

Looking back at Cobb and Campbell's cars of the 30's and 40's they had no reported issues arising from their DIF chassis layouts.  Nothing I could find said they used yaw strings to help with yaw feedback, but they apparently were able to overcome the lack of a seat of the pants feel that rearward driver positions are said to offer.  Here, the smallest frontal area possible is needed to take full advantage of the powertrain design for record speeds.  Based on the many different layouts we've covered so far the DIF position in V.5.5 is the best approach to maximize the hp to drag ratio numbers needed to hit a 600 mph goal.  So, unless we receive factual information to the contrary of the usefulness of a yaw string indicator we will progress forward with the current DIF layout.  Thanks... Terry

Offline Sumner

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Re: Simspeed UWD LSR Design Project
« Reply #156 on: August 13, 2019, 04:57:12 PM »
I'll have to agree with those that feel you can't be looking down the track and at something right in front of your face at the same time.  You mentioned Cobb or Campbell (can't remember which) crashing due to salt conditions.  How do we know they couldn't correct for those conditions due to their seating position?  On almost any run by a fast high powered car they are dealing with salt conditions as the track isn't anywhere near as consistent as say pavement.  It can look fast and hard and smooth but it isn't.  Your car has the potential to go much faster than Cobb and Campbell went so the driver is going to need all the help he or she can get.

My feeling on using something that is controversial from a safety standpoint is if it is my car and I'm driving it I might try something that I wouldn't try with someone else's life on the line.

Sumner

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #157 on: August 14, 2019, 12:50:50 AM »
I'll have to agree with those that feel you can't be looking down the track and at something right in front of your face at the same time.  You mentioned Cobb or Campbell (can't remember which) crashing due to salt conditions.  How do we know they couldn't correct for those conditions due to their seating position?  On almost any run by a fast high powered car they are dealing with salt conditions as the track isn't anywhere near as consistent as say pavement.  It can look fast and hard and smooth but it isn't.  Your car has the potential to go much faster than Cobb and Campbell went so the driver is going to need all the help he or she can get.

My feeling on using something that is controversial from a safety standpoint is if it is my car and I'm driving it I might try something that I wouldn't try with someone else's life on the line.

Sumner

Hey Sumner,
My contention is that the driver, like a pilot, doesn't have to look directly at the yaw string to benefit from the information it supplies.  I believe you can look down the track and still register movement of the string without looking at it directly.  Because it gives real time information of yaw movement a driver should be able to make use of that info in real time to make counter steer corrections.  I agree on the safety issue to the extent that I'd rather test something new myself rather than ask someone else to take the risk.  Thanks... Terry.

Offline Peter Jack

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Re: Simspeed UWD LSR Design Project
« Reply #158 on: August 14, 2019, 01:14:23 AM »
I'm not trying to be a smart a$$ but I just had an idea. Why don't you try mounting a devise of that sort on your regular street vehicle and then see if you feel it is really practical. I think you may change your ideas.

Pete

Online TrickyDicky

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Re: Simspeed UWD LSR Design Project
« Reply #159 on: August 14, 2019, 02:17:43 AM »
I'll have to agree with those that feel you can't be looking down the track and at something right in front of your face at the same time.  You mentioned Cobb or Campbell (can't remember which) crashing due to salt conditions.
...
Sumner
I think the reference was to Donald Campbell in 1960.

As far as I know, Malcolm Campbell never crashed (at Bonneville). His Blue Birds were also not DIF.

Offline Stan Back

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Re: Simspeed UWD LSR Design Project
« Reply #160 on: August 14, 2019, 03:28:31 PM »
Last I checked, an Isky Dream Wheel is $2.  They seem to be accurate to within 1% if you carefully use them.  The app allows you to carry it with you wherever you are and whether or not there is a signal available.  We got 7 SCTA records in the same category using one.  Just a thought.
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Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #161 on: August 15, 2019, 09:12:05 PM »
Congratulations to the Salt Shark team for their 288 mph for what I believe is the top speed of the meet.  The owner gave credit to his FWD setup for being able to deal with the poor track conditions.  Conditions must have been pretty bad for a 288 to take top speed.

But that leads to the question of how successful might a FWD setup be if that's all the traction put to use? Given equal HP might the FWD Salt Shark for example outperform the RWD Speed Demon?  How about the Simspeed project if FWD were tagged from start to say 300 mph, and then the RWD kicks in with 4 more wheels to boost max hp to the ground for whatever top speed can be reached?  With electric motor drives at all wheels power can be applied to each wheel independently at any given point in the run to best advantage depending on conditions.  Remember there's no transmission or gearing involved, the motors are direct drive with 3218 hp & 3270 ft/lb torque spinning up to 8600 rpm to reach 600 mph with the 23.5 wheel diameters.  Thanks... Terry.
« Last Edit: August 15, 2019, 09:15:33 PM by Simspeed »

Offline Seldom Seen Slim

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Re: Simspeed UWD LSR Design Project
« Reply #162 on: August 15, 2019, 09:52:42 PM »
Well, mmm, unh, the 715 car made three runs over 300 during the event. :roll:
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Offline RichFox

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Re: Simspeed UWD LSR Design Project
« Reply #163 on: August 15, 2019, 10:58:48 PM »
Congratulations to the Salt Shark team for their 288 mph for what I believe is the top speed of the meet.                                                     715 E BFS Speed Demon Racing 332.815

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #164 on: August 16, 2019, 12:29:35 AM »
Well, mmm, unh, the 715 car made three runs over 300 during the event. :roll:
Oh...my apologies to the Speed Demon team.  What I read was prior to those runs apparently.  Thanks for the correction guys... Terry