04-17-2020, 01:39 PM
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#211 (permalink)
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Master EcoModder
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on-the-fly
Quote:
Originally Posted by JulianEdgar
On-the-fly height-adjustable suspension has enormous aerodynamic advantages for those chasing best aero outcomes.
https://youtu.be/rN5nOCsLUUw |
Following the Cybertruck CFD controversy I spent over 8-weeks creating a rebuttal,illustrating why it might be impossible for Cybertruck to generate Cd 0.48,as some advocate,and a lot had to do with Tesla's active suspension.With 8-inches (203.2mm) of front and rear suspension travel,Cybertruck is provided with the potential to 'tune' the aerodynamics on-the-fly,using the entire underbody as a diffuser,as Ford Motor Company did with their Cd 0.152,1983 Probe-IV concept car,and probably their Cd 0.137,1985,Probe-V concept.
Somehow,this capability was never explored in the numerical simulations,while Hucho has provided empirical evidence demonstrating that attached,longitudinal vortices which would be necessary to explain such a high drag cannot exist in a potentially inclined body as Cybertruck possesses.
I'm in total agreement as to the significance of this technology.Great video! 
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04-17-2020, 02:49 PM
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#212 (permalink)
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Youtube wanted me to see this:
I don't see it mentioned in this thread. Too busy (I'll bet)?
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04-17-2020, 05:54 PM
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#213 (permalink)
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Quote:
Originally Posted by freebeard
Youtube wanted me to see this:
I don't see it mentioned in this thread. Too busy (I'll bet)? |
There are numerous videos I produce that I don't mention in this thread. Best to subscribe to my channel if you want to see what I launch. |
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04-17-2020, 05:55 PM
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#214 (permalink)
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Quote:
I run 3½ in the front, it looks better lower ( ) but there exist speed bumps.
Why a tail-dragger instead of a rake?
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The rear ride height is the same as the front ie the sill panel is level. The rear undertray is lower than the front undertray to increase flow speed and get more downforce. |
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04-17-2020, 09:08 PM
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#215 (permalink)
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Cyborg ECU
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Quote:
Originally Posted by JulianEdgar
Note: 1/3rd scale model, not full-size car |
So I take it that a roof spoiler with side spoilers that is overall about 3+ inches long and without an upward lip might reduce drag roughly 0.008 if I do it well and get lucky. And that lowering the ride height about 1.5 inches might reduce drag 0.010 if done right and interaction between various mods is accounted for.
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.
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04-17-2020, 09:47 PM
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#216 (permalink)
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Master EcoModder
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Quote:
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So I take it that a roof spoiler with side spoilers that is overall about 3+ inches long and without an upward lip might reduce drag roughly 0.008 if I do it well and get lucky.
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I'm not the expert here, but I'd point to the longitudinal vortexes generated by VW Beetles and Tesla's Cybertruck. 3 inch spoiler, Okay, but longer side spoilers (until it hurts sightlines).
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04-18-2020, 02:06 PM
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#217 (permalink)
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Cyborg ECU
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Quote:
Originally Posted by freebeard
I'm not the expert here, but I'd point to the longitudinal vortexes generated by VW Beetles and Tesla's Cybertruck. 3 inch spoiler, Okay, but longer side spoilers (until it hurts sightlines).
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Yes, longer than 3" ... I agree. I am also no expert. By saying 3+ I was anticipating something longer, but Julian's video only notes how much longer Porsche made the roof spoiler (something like 46mm longer), not how long it was in its earlier form, so I guessed. I cannot start another project right now, anyway, given how behind I am in current parts installation ...
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.
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04-19-2020, 01:03 AM
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#218 (permalink)
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Plotting the variation in undercar negative (ie downforce) pressures with ride height changes. On the Insight at least, no point in going below a certain ride height.
URL="https:// |
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04-19-2020, 02:10 AM
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#219 (permalink)
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Master EcoModder
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Were the sensors located at the front, rear or center of the trays?
Have you investigated unequal ride heights, IOW a slight rake?
At the end, Youtube recommended Zero cost modeling of space frame structures. One of my favorite Autospeed stories. It would benefit my ideas about housing design, (although that involves monocoque boxes).
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04-19-2020, 02:16 AM
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#220 (permalink)
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The sensors were located in the middle of the undertrays.
The electronic suspension system is easily set up for differing rakes but what I have seems to work pretty well, so I have left it. At my normal ride height (5 on the dial) it turns out I do have a lower front than rear clearance. (It must be only at '1' on the dial where the rear gets lower than front - and I never run '1' on the road.)
Yes I like the copper wire space frame modelling - but you wouldn't believe how that story was denigrated when it first appeared!
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