Madjak, what happens when you sit on it? Maybe holding some weight (no idea how much you weigh lol)

 

Official mt.net wing test:

1.) Hold ponies
2.) Sit on wing
3.) Take selfie

 

I think it should be something like this:

 

I'm just guessing here, but I would assume that wings are distributed load, not a point load. Standing/sitting on the wing while impressive, isn't going to prove it would hold up to 300lbs of total downforce.

 

While I'm pretty sure we were all joking about standing on his wing, 300lbs is still 300lbs.

Also, for the record you can absolutely stand on any real motorsports wing.

 

Correct, and even some flexing in the wing element is fine. Sure your profile is changing as it flexes, its not substantial, and your wing mounts flexing doesnt matter much either. Anyone who says differently is either an idiot or just regurgitating info without thinking about the physics. No ******* way am I going to sit on my wing. Did it break at 120 where it should be making in the 600lbs of downforce range? no.

 

It creaks a bit!

I'm a bit under 90kgs and with all my weight in the dead middle the wing must deflect around 15mm (5/8ths). I bounced up and down a bit and all up felt pretty safe. If I had the ceiling height I would feel fine standing on it even with my feet together in the middle of the span. I could imagine two more of me either side sitting nearer to the supports world start to stress it. I think a total load of around 300kgs spread equally would be the limit... any more and the deflection would cause a permanent bend or the plastic the crack and fail.

I think I'm more concerned about the main supports than the wing itself. Any large harmonic sideways motion when weighted up could cause the plates to twist and fail.

I'll get some pics taken of me and the kids sitting on it when someone else is around.

 

Dollars spent: $100
Hours spent:10 Hrs
How effective:No tested
Materials used:1/2" Birch Wood
Size/thickness of materials: 1/2"
Bracket location:Bracket at the very front of frame
Tracks tested on:none
Race/TT class built for: Autocross SSM(not committed yet)

Please give feedback


Splitter cardboard template


Front bracket to frame


Front bracket through bumper


The air dam is not fastened




Driving home without the air dam

 

brace the rear and sides too. 2 braces up front is not enough.

 

1/2" birch is rigid enough that it may be adequate. It will deflect to some extent still, but likely not an undesireable amount considering autocross speeds. 3/8" birch needs more support.

-Ryan

 

I did brace the back, it is braced at the front of the sub frame. I will take pictures next time I work on it. For the sides I will add braces, thanks for your comments

 

So I was a little out.... plastic wing weights 4.72 kgs with endplates. Add another 750 grams for the main supports and bolts.

 

Thats really not bad at all. Now for your next wing, and now that I've seen you do this probably my next wing, make the wing cross sections almost completely hollow with spokes to transfer the load from the skin to the tubes and wrap carbon or FG over it. The 3d printed parts probably came out way more accurate than my laser cut styrofoam core slices, and I'd 100% be willing to trade some strength to weight ratio to avoid the 100+ hours of fixing the profile wavyness due to the laser cutting.

 

The plastic parts are only 1.8kgs as I know from the print material required. I think you could get it down to 1.5 but there needs to be some internal structure as the plastic expands and shrinks during the print and without lots of support it will warp.

Also if you use an internal rib structure it will need support around it.

On my wing, there is no outer skin to take the flex load so most the force is distributed by the two ally ribs... they are probably larger than ones in traditional wings.

 

Have you speed tested it yet?

 

Dollars spent: $160 (150 for diffuser shipped, $10 for bolts and brackets)
Hours spent:5 Hours
How effective:No tested
Materials used:Angle aluminum for brackets, stock elise differ
Bracket location:Bracket at the back of rear sub frame, and bracket under far back of rear frame
Race/TT class built for: Autocross SSM(not committed yet)

I mounted the rear diffuser late night, didn't route the exhaust or cut out the bumper. The heat in that area melted the tail light on the freeway and deformed the bumper. (listen learned)


The next day I reroute the Exhaust to the center and cut out the bumper





Please give feedback. This is a part of complete flat belly. part 1 was posted on top (4-14-15). Part 3 should be coming in 3 weeks. Need to do a little more research. Thanks in advance

 

Elise diffuser isn't too great a design. Outer tunnels have flow separation and airflow actually flows back towards the diffuser.

 

Wow I would have never thought that a lotus diffuser wouldn't be designed well. What you said makes sense, I just saw a video of wind tunnel and it appeared to be doing that.

Thanks

 

its about time I sub to this thread... lots of good stuff going on here

 

Subbed for more excellent rainy day project ideas!