Rear wing downforce comparison sheet

[Tex Koder]

I made this one for the Limitless 2 years ago. No one ever noticed but it looks like stock...
Sent it over to you Lennart if you want to check it out. I never tried it in a simulation so maybe it sucks

View attachment 355376

View attachment 355377

You so sneaky..

 

[Dan B.]

@LibertyMKiii , Want to print me a couple in basic black? If they end up not sucking, of course.

View attachment 355377

 

[Greengaunja]

I don't want to come across as rude or arrogant, but also want to take an opportunity to educate when possible. I fully realize aerodynamics are a highly misunderstood topic.
Using a carbon fiber plate is basically like using the rectangle block like shown in the 2nd image.

View attachment 355323

No not rude at all. And you'e right. I toyed with the idea of using thicker plates and belt sanding curves. But as I stated in the thread I did when I made them, they were always meant to be cosmetic. And i only went that route because i couldnt find one that comllimented the C7 body. Plate was just easier and faster to make. But yeah, the aerodynamics are the same as with an airplane, just creating downforce rather than lift. But I'm sure there is some downforce being create, just not alot or in any efficient manner.

Before I forget, take a closer look the upper deck. The front of it is sanded down to removed the edge. Originally it was to be a 1 deck wing with layers added to the rear to sand into curves

This thread has been awesome because of the contributions. Even I learned a thing or two regarding aerodynamics.

 

[LibertyMKiii]

@LibertyMKiii , Want to print me a couple in basic black? If they end up not sucking, of course.

Yeah man either myself or @Tex Koder could print you some (assuming he wouldn't mind).
My printer is rather questionable right now.

 

[dure16]

I made this one for the Limitless 2 years ago. No one ever noticed but it looks like stock...
Sent it over to you Lennart if you want to check it out. I never tried it in a simulation so maybe it sucks

View attachment 355376

View attachment 355377

That wing looks great man. Did you post the file anywhere? I'm just starting to shoot for higher speeds with my limitless so aero is on my mind.

Yeah man either myself or @Tex Koder could print you some (assuming he wouldn't mind).
My printer is rather questionable right now.

I can help as well

 

[LibertyMKiii]

That wing looks great man. Did you post the file anywhere? I'm just starting to shoot for higher speeds with my limitless so aero is on my mind.


I can help as well

https://www.thingiverse.com/thing:6538759/files

 

[Dan B.]

Yeah man either myself or @Tex Koder could print you some (assuming he wouldn't mind).
My printer is rather questionable right now.

That wing looks great man. Did you post the file anywhere? I'm just starting to shoot for higher speeds with my limitless so aero is on my mind.


I can help as well

That does look great. I wouldn’t need the reliefs in the center, just the proper airfoil with about 20mm of the outside bottom edges to be printed flat so I could use the Scorched wing brackets:
https://scorchedparts.co.uk/product...arbon-fibre-wings?_pos=1&_sid=645f80183&_ss=r
I would not be hung up on impact strength as long as they would be rigid. And the smoother the finish, the better.
Seriously, take my money!
@Tex Koder , @dure16 , the file is right there.
https://www.thingiverse.com/thing:6538759/files

 

[Tex Koder]

.

Yeah man either myself or @Tex Koder could print you some (assuming he wouldn't mind).
My printer is rather questionable right now.

https://www.thingiverse.com/thing:6538759/files

No worries sir.
I got your back.

Thank you @LibertyMKiii

That does look great. I wouldn’t need the reliefs in the center, just the proper airfoil with about 20mm of the outside bottom edges to be printed flat so I could use the Scorched wing brackets:
https://scorchedparts.co.uk/product...arbon-fibre-wings?_pos=1&_sid=645f80183&_ss=r
I would not be hung up on impact strength as long as they would be rigid. And the smoother the finish, the better.
Seriously, take my money!
@Tex Koder , @dure16 , the file is right there.
https://www.thingiverse.com/thing:6538759/files

I'll get them loaded later tonight..

PM me, let me know how many you need and where to ship.

 

[Dan B.]

Will do. I’ll try to get an accurate width as well.

 

[dure16]

https://www.thingiverse.com/thing:6538759/files

I appreciate it!

 

[LibertyMKiii]

I appreciate it!

One thing to note is that some downforce is a good thing. Especially when starting out with speed running.
If you find that its lacking traction then you may want a different wing.

I can always custom design something if needed.

Sorry @Lennart I didnt mean to hijack your thread. This limitless wing caught more attention than I expected.

 

[Lennart]

Sorry @Lennart I didnt mean to hijack your thread

No worries, I mean it is all on the topic I imagined would be discussed here.

I will do a simulation with the single-element airfoil wing.
The wing looks easy to print with the flat top half
Without having done the simulation, I think it is safe to say it will outperform a 3mm flat plate anytime when it comes to the aero.

 

[Greengaunja]

You know, it just occurred to me that as per usual, I had it all ass backwards. When I was thinking of sanding out a curve, I was looking at it as "flipping an airplane wing around". More specifically, I would have had the thickest part of the wing at the rear. So just for science sh1ts and giggles, how would that way have performed?

 

[LibertyMKiii]

You know, it just occurred to me that as per usual, I had it all ass backwards. When I was thinking of sanding out a curve, I was looking at it as "flipping an airplane wing around". More specifically, I would have had the thickest part of the wing at the rear. So just for science sh1ts and giggles, how would that way have performed?

Verrrryyyy common to think of it that way. I guess seeing rockets and bullets etc, you think pointed edge cuts through the air best.
The truth is for speeds below the speed of sound a more rounded blunt leading edge works best. This is why you will see fighter jets being very pointed versus a passenger jet that flys at speeds below the sound barrier is much more smooth and rounded.

I don't think the performance for your RC car will be drastically different, but the wing won't work as good backwards.

 

[Lennart]

The flat wing is finished. Pretty efficient, I looked twice at the 27 grams of drag at 126kmh.

But keep in mind its completely flat in the simulation with no mounting holes and I extended it to 30cm in width, like all other sims. (except the limitless style wing)
With a width of 217mm it would be less efficient because longer wingspans are generally more efficient. And less drag/lift of course.
The stock limitless wing produces much more downforce. But this wing creates some downforce extremely efficiently.


You can see the downforce graph is smooth, so not much turbulence compared to flat plates with relatively sharp leading edges.

 

[LibertyMKiii]

The flat wing is finished. Pretty efficient, I looked twice at the 27 grams of drag at 126kmh.

But keep in mind its completely flat in the simulation with no mounting holes and I extended it to 30cm in width, like all other sims. (except the limitless style wing)
With a width of 217mm it would be less efficient because longer wingspans are generally more efficient. And less drag/lift of course.
The stock limitless wing produces much more downforce. But this wing creates some downforce extremely efficiently.


You can see the downforce graph is smooth, so not much turbulence compared to flat plates with relatively sharp leading edges.

View attachment 355539

View attachment 355540

View attachment 355542

Awesome it works! Low drag and a little downforce with high efficiency. Thanks @Lennart

 

[Dan B.]

That could also be angled a bit to increase downforce if you wished.

 

[Lennart]

IF the wing is angled just slightly thats ok. I would not angle the wing more than 4 degrees or so, because of possible flow separation. When that happens more drag and less downforce is the result.

One could stick or glue or screw a gurney flap on the wing would be a "safer" alternative. This would also help with flow separation when the wing is angled.

On my wing the gurney adds 16% Lift and 26% drag. (More angle of attack will also make the wing less efficient)

 

[Tex Koder]

IF the wing is angled just slightly thats ok. I would not angle the wing more than 4 degrees or so, because of possible flow separation. When that happens more drag and less downforce is the result.

One could stick or glue or screw a gourney flap on the wing would be a "safer" alternative. This would also help with flow separation when the wing is angled.
View attachment 355552

On my wing the gourney adds 16% Lift and 26% drag. (More angle of attack will also make the wing less efficient)

View attachment 355553

"Gurney Flap"
I learned a new word today.

Thank you.

 

[Greengaunja]

I'm curious as to whether or not the program you are using only measures the aerodynamics of wings or can it be applied to a car?
Back when I first took to speed running I always said it was my goal to get my build to go as fast as possible with its proper body. And we all know that the Senton body has aerodynamics that match a brick. Yet when I stuck the Limitless front end on it, I saw potential with another idea. One I will try this year. Was trying to keep it under wraps as I may even try to go for a ROTM with it when I do a new body. But I VERY curious if what I did will actually beat my stock body PB of 104mph. Except the build changed so much that I'm pretty much guaranteed to top it now regardless of this addition simply because I have a better esc and motor, along with other tweaks done.
Man, I used to have alot pride that I had alot of practical knowledge as opposed to the "useless computer crap". And lately with stuff like the program you're using and CNC, just to name two, has me lacking and wanting...Weird how that turned out.