Aerodynamics-- request for project help - Page 2 - PeachParts Mercedes-Benz Forum

hetiticth · #16 10-08-2013, 10:45 PM

Quote:

Originally Posted by Jooseppi Luna

Just a thought -- the metalwork in shaping the body panels may be one of the tougher parts of the project. I've always thought it would be fun to build my own car, but I'd thought of something more like a Jeep-type body for ease of fabrication. What kind of frame would you be using? Ladder? Perimeter? Where would you get the metal for this project?

I'd say go nuts, at least design it. Designing is a lot of fun, and you'll certainly learn a lot in the process. If you actually build a car, no-one will be able to question your user title

.

Quote:

Originally Posted by Jooseppi Luna

I would also look into what you need to do to register a homebuilt vehicle in NM. I wonder what would happen if you got hit in the car in terms of insurance... how would they determine the value of the car and how would they determine the repair cost?

I've done a bit of fabrication before, on a Jeep that I turned into a dune buggy. It turned out pretty well, though it was just simple stuff

I wanted to do something that was a lot more advanced, because I have access to the machinery for more advanced stuff during the summer. For the rest of the year though, just working at an auto body shop will have to suffice

For the frame, I will likely be doing a mixture of several different styles (except unibody), in order to be as structurally sound as possible. I think that the car will also have a basic roll cage, for safety and ease of construction/replacement of body panels in the case of an accident.

And as far as I know, in order to register a homemade vehicle in New Mexico, all you need is to get it weighed, inspected, have a part list, and you are good. I don't know about emissions though... Guess it is lucky I don't have to do testing in my county!

Mölyapina · #17 10-08-2013, 11:23 PM

Well then you apparently can actually do bodywork (Unlike someone else here)

. Here's another thought -- since this is being designed, could you build in room for a 7:1 brake pedal ratio and long travel so that you could forgo power brakes?

hetiticth · #18 10-08-2013, 11:23 PM

Quote:

Originally Posted by P.C.

I would look at 1968-up Corvette's for GM's solution to having a low radiator height while addressing the cooling demands of a small block Chevy.

Quote:

Originally Posted by Jooseppi Luna

Ah, and please make it with a standard

.

You have a 94% chance of that happening! The remaining 6% depends on whether or not I decide to attach wings and make this into an airplane.

I am not set on the small block Chevy, but it is on the top of my list, because my family is a Chevy family (and on my Dad's side, they all race), the parts are readily available, and there are some that are pretty lightweight.
Of course, alterations could be made fairly easily to allow for a better cooling system. I was thinking of having the radiator in the front, with a partition on the center of the radiator that let the wind flow out through vents in the body (like in the original design).

Looks like I was wrong about it being front engined, RWD!!

The original car was put on the Mercedes 170H chassis (above).
My design would be a bit... sturdier.

Here are a few more pictures of the car:

t walgamuth · #19 10-08-2013, 11:27 PM

That is a cool looking car!

hetiticth · #20 10-08-2013, 11:34 PM

Quote:

Originally Posted by Jooseppi Luna

Well then you apparently can actually do bodywork (Unlike someone else here)

. Here's another thought -- since this is being designed, could you build in room for a 7:1 brake pedal ratio and long travel so that you could forgo power brakes?

Haha well, I can do fabrication a lot better than repairs! I generally mess up when repairing fenders and the like (from the three times I have done repair work). Spot welds are really annoying!

For the pedal ratio, isn't 6:1 more common? I have remembering issues

I suppose it wouldn't be a problem, though I think that kind of detail would be best worked out after some other more important details, and it would probably be related to the weight of the car...

Regardless, I am on the edge about power steering and brakes. While it is more "safe" with those systems in place, they do make it considerably more difficult to maintain. I should add that to my list of goals: Easily maintainable. Yeah.

hetiticth · #21 10-08-2013, 11:37 PM

Quote:

Originally Posted by t walgamuth

That is a cool looking car!

It's pretty awesome, yeah? It remind me a lot of the VW Karmann Ghia, which I am much more familiar with (my mom has one-- 1957). A problem with the Ghia, that may translate over to this car, is high speed stability. I know that the original wasn't very stable, and had terrible steering... another thing to change?

Skippy · #22 10-08-2013, 11:39 PM

I've had a vehicle without power brakes. I would say go ahead and take the weight and complexity hit and do power brakes. As for power steering, if the front end weight of the vehicle is fairly light, non-power steering can be quite acceptable. If you go with rear or rear-mid engine, the front will probably be plenty light to go with non-powered rack and pinion steering.

hetiticth · #23 10-08-2013, 11:56 PM

Quote:

Originally Posted by Skippy

I've had a vehicle without power brakes. I would say go ahead and take the weight and complexity hit and do power brakes. As for power steering, if the front end weight of the vehicle is fairly light, non-power steering can be quite acceptable. If you go with rear or rear-mid engine, the front will probably be plenty light to go with non-powered rack and pinion steering.

I've driven a few vehicles that were without power brakes that were very easy to stop. I think it just depends on how it is set up. More than likely though, the initial design will have normal brakes, and if it exceeds 2500lbs, I will switch to power brakes.

EDIT: I am also considering a frictionless braking system, using magnets. It seems like it would be easy to do, and would make things last a lot longer.

tbomachines · #24 10-09-2013, 12:22 AM

might as well go all out? A thing of beauty IMO

hetiticth · #25 10-09-2013, 12:38 AM

While it is a thing of great beauty, that Talbot Lago (unless I am mistaken), has a CD of about .27-- which isn't the greatest.

I think that the interesting thing about the Maybach is that there aren't any left. I think that they made two, both of which were lost during WWII.. It seems like it would be an excellent model for a supercar!

t walgamuth · #26 10-09-2013, 07:08 AM

I would estimate the cd on this car in the low 20's. It'll be a ton of work to build. Power brakes are totally not needed. Just size the master cylinder with the wheel cylinders correctly and you'll be fine with a nice light vehicle like that.

Mölyapina · #27 10-09-2013, 07:09 AM

Yeah, 6:1 is more common, but why not 7:1

? More force multiplication is a good thing in my book...

hetiticth · #28 10-09-2013, 08:32 AM

Quote:

Originally Posted by t walgamuth

I would estimate the cd on this car in the low 20's. It'll be a ton of work to build. Power brakes are totally not needed. Just size the master cylinder with the wheel cylinders correctly and you'll be fine with a nice light vehicle like that.

The only CD I have seen for this car was ~.16-- which is very good. The only problem though, is that I don't know how reliable the sources are..

t walgamuth · #29 10-09-2013, 10:06 AM

That looks like a Mercedes 170 (something) chassis. ... Designed by Ferdinand Porsche.

hetiticth · #30 12-16-2013, 04:41 PM

I've been gone for awhile, and I think that you all are way overdue for an update.

For the car, I know that I will be going with a small-block Chevy v8, as I have two available to me now (a stroker 383 and a stock 305).
I am pulling a 6 speed standard out of an old Pontiac that has a seized 350 in it.

For the chassis, I am planning on building either a tubular chassis like what is found in dirt modifieds, or a ladder style frame. I have started to work with a CAD program to design both, and with the aid I am getting from one of my Dad's friends, who is a retired structural design professor, I hope to create as sturdy a chassis as I can. I am leaning more towards the tubular chassis, as it will be easier to attach body panels to.

As for the body panels, I want to try to use fiberglass, because it doesn't rust, and can be lighter than steel.

Other things on the list:
Looking at having all around independent suspension (meaning front and rear)
Disc brakes on all four wheels
Limited Slip differential
Eddy current brake (still a maybe.. weight might be an issue)
Two front seats, plus one rear bench seat
Easily removable body panels
Dry sump oil system

I think there might be a few other things I have forgotten to mention, but they will have to wait until I get home. I am getting kicked out of Starbucks because I have been stealing their internet for too long!