SLC 24 Howard Jones

[Fran Hall RCR]

Its the system that Howard is using the make the car look "shrubbery" when its finished...or it could be that he is on the "verge" of finishing...or maybe he is just making sure the grass is not greener on the other side...

he is from California you know...

 

[Howard Jones]

Ya............ that should have been "henge" system for the rear clip. The barackets are the mount points for the rear wing. I want to be able to run it with or without the diffuser so I don't want to mount the wing to it.

 

[Mesa]

Poor Howard spent too much time with Jim Craik today....he has Barak-ets Obama on his brain.

 

[Howard Jones]

First look at wing mount. It's all .58 X 1" CM. I went and made the pivot tabs on the wing double shear. I had the tabs so what the hell. The whole thing comes off with four bolts for now. I may use T pins, sometimes called quick pins, with indents in them later.

There's a ways to go yet. I still have a cross brace and a diagonal to weld in. The wing will be higher, up in clean air about at the top of the roof line.

 

[Alex]

Oh wow, you weren't kidding about that wing being taller up. That's going to be hiiiiigh!

 

[Howard Jones]

Observation. Copy what works! Sucess.

 

[Damian]

I have a question about the supports for the race SL-C wing; why do the supports come up, over, and back over the wing. Wouldn't it be less weight, turbulence (drag) to just affix the supports at the bottom of the wing like the factory set up? I have noticed a few race teams with this set up but it never made any sense to me can someone explain to my what the thought process is and what the benefits are?

 

[Jim Craik]

Rob,

Do not forget, you spent time with me as well! That should set you both back quite some time

Damian, I know it looks odd. I think the reason they do this is that aero wise, the bottom of the wing is the most critical, you do not want to disturb that air if you do not have to.

 

[Fran Hall RCR]

Jim,
absolutely correct....

 

[Doc Kaler]

Jim and Fran,

Intuitively, I understand why you don't want to disturb the lower surface air flow. But, the question in my mind is "would vertical plates be helpful, or at the least not be harmful, when the airflow is not perpendicular to the wing's cord, ie., cornering?" During these conditions the wing's cord is changed relative to airflow over it, lengthened somewhat. This would "flatten" the cord somewhat, reducing downforce. So, a vertical plate would help to keep airflow perpendicular to the intended cord shape similar to the endplate's design to prevent wing-tip vortices.

Just want an aerodynamicists thoughts to educate me.....

 

[Jack]

Also called "fences"..

 

[Howard Jones]

The wing end plates prevent the surounding higher pressure air from intruding into the low pressure area under the wing. In effect, this makes the wing longer and thus more effective. Vortex production at the wing tip is the process of that intrusion.

On race cars with rules this is very important. Drag is very expensive from a HP cost perspective. Rules tend to limmit both HP and overall downforce(drag) and therefor the more downforce that can be produced with a given wing setting the better.

In my case.....No rules. I am a little concerned about high speed areo push however. I don't have the race version of the front splitter and it will be interesting when I get it on track and start working on areo setup. That is a really big wing on the back and it might not be possible to use all of the downforce produced by it without improving the front in a balanced way. At this point I will be making some form of canards for the front at least.

By the way does anybody have any data on angle of attack settings and best practices on how to measure it on an SLC rear wing? At least some idea of range of adjustment?

 

[Damian]

Thanks guys; I thought it might be something like that but wasn't sure and wanted someone in the know to educate me (thanks again).

 

[Howard Jones]

I got the henges, Thanks Fran.

 

[Howard Jones]

Wing mount finished. As you can see it is nice and high up above the body at about the same height as the top of the cabin. I set it at 2 degrees leading edge down with the ability to increase the angle of attack another 8 degrees for a total of 10 by changing the length of the adjustable link. I am sure I could get another 5-6 degrees if I fool with the other rod ends at the chassis mounting points.

This was done with a straight edge across the top of the wing and a angle finder on top of that.

The mark 1 eyeball says that about right, with 10 degrees down more than likely more than necessary. The only way to really tell, is run the car. I guess we'll find out later.

Anyway the mount came out real strong. I looked at a lot of pictures of racecars and in the end I used a design I see on a lot of top fuel dragsters. The idea being if they can keep it on the car at 300mph it must work.

The whole thing is 1X.058 4130 CM with the vertical diagonal links 3/4X .065. Very stiff.

 

[Doc Kaler]

Very nice Howard! I like your adjustable front struts....

 

[Fran Hall RCR]

Howard,
You have the less agressive wing profile ...the Carbon race wing has a more much agressive L/D ratio...Selig 1223 for you tech guys ...

Nice work..

 

[Ricardo Montalvo]

Looking good Howard. It's getting close...

 

[Mesa]

Robust, adjustable and 300mph capable, Howard may have some engine upgrades going in the Skunk Works Looks better than the one I made out of wood, that's for sure.

 

[Howard Jones]

Fran what should I be trying for settigs on this wing. So far I am going with best guess and a common sense. Based on what I have so far, am I within workable limmits.

Howard