SammyXp

I convinced the model shop here at work to buy a vacuum forming machine so it looks like I won't need to build one myself. The FDM mold is running right now (had to freeze the design quick, so no canopy for this go-around). Little bit of concern about how many shells we'll be able to pull off the only moderately robust FDM prototype mold. I might cover the mold in aluminum foil to help shield it from the heat.

What was the bulk of your cost, that made it prohibitive to further production?

SammyXp

Kinda hard to see in this photo, but it doesn't look like there is a great deal of turbulence at that rear shock tower hump. I'm going to leave it as it is. The analysis didn't come to full convergence, but the vector at the hump was in the process of straightening out as the solution converged, so I suspect it would only get better.
I ran the analysis first without the wing, just to see it run. Seems like an impressive amoutn of downforce for the amount of drag. Then again, I don't have another model to compare to (anyone have an IGS file of a sedan?).

RcCzarOfOld

Impressive numbers Sammy. Could you possibly run it again at 50mph?

When you get a few units ready for paint and mounting, I'll have paypal ready for at least 1.

Tony

SammyXp

Yeah, they do seem impressive, don't they? For all I know, the Alpha generated ten lbs of downforce with only a half pound of drag, though. haha

I'm running another one at 30mph with the wing. Then I'll try it at 50. Takes about an hour to run so hopefully I'll have both runs done by this afternoon.

SammyXp

Geez took me forever to figure out that you can't put a 0.075 mesh on a 0.050 thick wing! Finally got 50 iterations to run, though. Solution is more realistic than previous.



About a pound of drag and 2 lbs of downforce. Seems more realistic. Rear wing seems a little unimposing, though. Especially when compared to the front. Running a much more aggressive wing overnight. Results to be posted in the AM.



The airflow seems to glide right over all the geometry in the center section. Including the potentially worriesome rear shock tower hump.



So I'm thinking the main design challenge in fitting a LMP body to a touring car is clearing the front shock towers without creating massive front downforce that can't be overcome with an adequately sized rear wing. Make a heck of a small track body, though!

gresults

I might be able to help you out on forming your body..just drop me a line at [email protected], I have a nice factory built unit that I pull spoilers off of for my 1/4 scale cars.

Birky

iTrader: (1)

Love the design mate, keep posting with your progress.
Ben

hgcolors

iTrader: (9)

or maybe you can wait for this tamiya body to come out..................

SammyXp

Oh man, that Courage is hot! I need a cigar!
Is that made for a touring car, though? Doesn't seem like it would clear the shock towers in the front and rear.

GResults, once I get this mold finished, if it looks like a vacform machine isn't going to show up anytime soon, I may get with you to pull a few bodies to get us started.

Birky

iTrader: (1)

Its made for the Tamiya F103GT (2WD, No Shock Towers): http://www.tamiyausa.com/product/ite...oduct-id=58367

SammyXp

Argh. That thing is sweet! The only picture of a LMP type body on what seems to be a touring car is this one. Looks to be a Group C Porsche on some kind of Nitro TC. No idea who makes it.

Birky

iTrader: (1)

Yeah a few years back Tamiya did a few Le Mans cars.

- Toyota GT-ONE
- Audi R8
- Porsche 911 GT1
- Nissan R390GT1

The first three were for the first F103's but the R390 was for a touring car chassis.

SammyXp

Yeah, doesn't seem like it's much of a challenge to fit a LMP on the F103. The R390 is a little easier since it doesn't have an underbody with channels between the cockpit and fender pods. Probably still has a ton of downforce. I'd love for someone to compare their R390 to this shell when it is ready.

I still wonder who made that Porsche in the pic above?

SammyXp

Finally got convergence and the numbers have changed. Also finally got it to run at 5mm ride height. This reduces the downforce numbers tremendously. No joke here, get the body as low as possible for max downforce! I might run another simulation at 6mm to see what just 1mm does, with no other changes.

@30mph:
Drag: 0.80lbf
Downforce: 0.35lbf
Center of pressure: 4.5" behind front wheels (56% front balance) and approx 3/4" from the ground. I was really surprised to find that the center of pressure was that low. If this body doesn't generate another ounce of downforce vs the Mazda and Stratuses of the world, the low CP alone might help you realize some noteable gains in stability and cornering ability.

Trace Lines show that the rear shock tower hump isn't bad at all. Might even be accelerating the air a bit before going beneath the wing. The wing seems high enough to capture any air that gets catapulted by it.

RcCzarOfOld

Hey Sam, any news of late? How are things going with the shell?