Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-20-2021, 02:22 PM   #571 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,561
Thanks: 7,736
Thanked 8,554 Times in 7,041 Posts
That was my hope. The Cybertruck establishes that longitudinal creases can work, but a compound curve give more interior space.

Are you going to roll the sides down as on the left, or go to the corner as on the right? Will the whole thing alligator, or what do you plan for bed access?

__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
The Following 2 Users Say Thank You to freebeard For This Useful Post:
California98Civic (06-20-2021), tomi_k (06-20-2021)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-20-2021, 02:27 PM   #572 (permalink)
EcoModding Apprentice
 
Bicycle Bob's Avatar
 
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,803

Appliance White - '93 Geo Metro 4-Dr. Auto
Last 3: 42.35 mpg (US)

Stealth RV - '91 Chevy Sprint Base
Thanks: 91
Thanked 459 Times in 327 Posts
Quote:
Originally Posted by freebeard View Post
That was my hope. The Cybertruck establishes that longitudinal creases can work, but a compound curve give more interior space.
The Cybertruck establishes that stylists can copy unsuitable shapes from stealth aircraft, just as they sold millions of cars with unsuitable shapes from supersonic aircraft. Flat panels are not even good structural practice in metal - Citroen used to corrugate them.
__________________
There is no excuse for a land vehicle to weigh more than its average payload.
  Reply With Quote
The Following User Says Thank You to Bicycle Bob For This Useful Post:
California98Civic (06-20-2021)
Old 06-20-2021, 06:37 PM   #573 (permalink)
Banned
 
Join Date: Nov 2017
Location: Australia
Posts: 2,060
Thanks: 107
Thanked 1,605 Times in 1,136 Posts
Tuft testing will be very interesting. Once you have attached flow, a rear spoiler lip may further reduce drag and lift.
  Reply With Quote
The Following User Says Thank You to JulianEdgar For This Useful Post:
tomi_k (06-20-2021)
Old 06-20-2021, 07:23 PM   #574 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Ontario, Canada
Posts: 68
Thanks: 54
Thanked 50 Times in 35 Posts
freebeard : Still puzzling with the those two options - straight to the corner (easier, more room, no sharp corners when opening bed door etc.) vs. rolled / blended sides (reduces "sharp" corner between the top and side walls -> tiny vortex, more complicated split line between the cap and cap door but could be a tad better from aero perspective).

So key thing is to keep in mind how to shape whole cap while making sure that it can be also finished (continued after prototyping) and the main cap shape and the cap door shape can be split / separated "easily" and then finish. But main focus for now is to make prototype(s) and get proofs of improvements, and then focus how to make finished one.


Rolled / blended sides as shown on the pics is just one option (they are straight lines looking from the top of the vehicle). More complicated option is to make the view from the top also "tier drop shape" but lets see... And yes, there will be a cap door, almost whole top surface (at least that's the plan) but it's limited to bed length at the moment. The extension piece (when bed door is open as shown) is now planned to be separate piece which can be taken out as needed (to further improve aero -> especially for long distance travels).

JulianEdgar : Was planning to do a half truck tuft (longitudal) test before anything as a baseline and then see what happens with the cap + mods...

In general, after reading this forum (thanks for the Admins, this is great stuff), I am confident that improvements can be made and that they are effective.... just need to get data from my own vehicle.

Last edited by tomi_k; 06-20-2021 at 07:34 PM..
  Reply With Quote
Old 06-20-2021, 07:38 PM   #575 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Ontario, Canada
Posts: 68
Thanks: 54
Thanked 50 Times in 35 Posts
Regarding drag and lift.... trying to minimize tail surface are yet still keep shapes "laminar" hence sharp corner where airflow "wraps" around corners are under details....

Well shaped form will start to remind a wing upper surface which creates lift so need to be careful also while testing....

If all goes well, then next will be underbody mods (full length)....
  Reply With Quote
Old 06-20-2021, 07:40 PM   #576 (permalink)
EcoModding Apprentice
 
Bicycle Bob's Avatar
 
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,803

Appliance White - '93 Geo Metro 4-Dr. Auto
Last 3: 42.35 mpg (US)

Stealth RV - '91 Chevy Sprint Base
Thanks: 91
Thanked 459 Times in 327 Posts
The first time I talked with a professor of fluid dynamics, almost the first thing he cautioned me about was trying to copy skin-on-frame shapes like a glider fuselage. Those creases don't matter for aircraft, but with a crosswind, they throw everything off. Be sure to test for that.
__________________
There is no excuse for a land vehicle to weigh more than its average payload.
  Reply With Quote
Old 06-20-2021, 07:45 PM   #577 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Ontario, Canada
Posts: 68
Thanks: 54
Thanked 50 Times in 35 Posts
If understood the "skin-on-frame shapes like a glider fuselage" correctly, I will take different approach, even for prototype(s).... it will be a firm surface....
  Reply With Quote
Old 06-20-2021, 07:48 PM   #578 (permalink)
EcoModding Apprentice
 
Bicycle Bob's Avatar
 
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,803

Appliance White - '93 Geo Metro 4-Dr. Auto
Last 3: 42.35 mpg (US)

Stealth RV - '91 Chevy Sprint Base
Thanks: 91
Thanked 459 Times in 327 Posts
Quote:
Originally Posted by tomi_k View Post
Regarding drag and lift.... trying to minimize tail surface are yet still keep shapes "laminar" hence sharp corner where airflow "wraps" around corners are under details....

Well shaped form will start to remind a wing upper surface which creates lift so need to be careful also while testing....

If all goes well, then next will be underbody mods (full length)....
You won't stand any chance of getting laminar flow that far back, but turbulent flow is much more forgiving. Also, since you are not racing, you can probably accept a bit of upforce if it reduces drag.
__________________
There is no excuse for a land vehicle to weigh more than its average payload.
  Reply With Quote
Old 06-20-2021, 07:51 PM   #579 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Ontario, Canada
Posts: 68
Thanks: 54
Thanked 50 Times in 35 Posts
may have my terminology wrong about "laminar".... but target is to get a good attached flow over the whole cap (not turbulent)... testing will show that how well it was achieved....

Last edited by tomi_k; 06-20-2021 at 07:56 PM..
  Reply With Quote
Old 06-20-2021, 07:59 PM   #580 (permalink)
EcoModding Apprentice
 
Bicycle Bob's Avatar
 
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,803

Appliance White - '93 Geo Metro 4-Dr. Auto
Last 3: 42.35 mpg (US)

Stealth RV - '91 Chevy Sprint Base
Thanks: 91
Thanked 459 Times in 327 Posts
Quote:
Originally Posted by tomi_k View Post
may have my terminology wrong about "laminar".... but target is to get a good attached flow over the whole cap (not turbulent)... testing will show that....
Large scale turbulence is detached airflow. Boundary layer turbulence is almost inevitable, and works as a cushion. The thicker it is, the more basic drag you get, but also the greater resistance to separation. If a shape is too abrupt, we deliberately add boundary layer turbulators.

__________________
There is no excuse for a land vehicle to weigh more than its average payload.
  Reply With Quote
The Following 2 Users Say Thank You to Bicycle Bob For This Useful Post:
freebeard (06-21-2021), tomi_k (06-20-2021)
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Easy Aero Fix? (Modding a pickup?) DifferentPointofView Aerodynamics 53 04-13-2012 05:46 PM
SAE report: Pickup Truck tailgate aerodynamics... better up, down, or off? MetroMPG Aerodynamics 5 11-17-2011 02:35 PM
Sources of Aerodynamic Drag in Automobiles and Possible Solutions SVOboy Aerodynamics 12 02-17-2010 02:09 PM
How much do y'all pay for trash pickup? roflwaffle Saving@Home 15 08-23-2009 10:46 AM
Daihatsu Mira aerodynamic modifications newtonsfirstlaw Aerodynamics 5 06-13-2009 09:43 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com