On Thursday, December 19, 2019 at 4:29:23 PM UTC-5, wrote:
It looks like I'll be retiring in 2 years or less. So then I'll
have time to make my sports car. WOOHOO!
To that end I am reading, for at least the 5th time, Racing &
Sports Car Chassis Design by Michael Costin and David Phipps. And have
been browsing the web for folks who have done similar.
Lotsa variations on the Lotus 7 I see. I like the Lotus 7 from the
front and the side but the squared off back end bugs me. The open
cockpit looks great but living just a bit north of Seattle makes me
think I need a hard top.
Reading about the first iteration of the Lotus 7 I find that it had
considerable lift in the front starting about 70 miles per hour. I
will only ever be driving it that fast on straight roads but any lift
could seriously affect the steering in a negative way. I guess this
problem has been addressed in later models and in the Locost and
Caterham versions.
But it looks like all the newer versions have fenders that have a
channel cross section, not a curved cross section like a motorcycle
fender. To me they look like ****. The original Lotus had the curved
cross section rear fenders and front fenders which were basically just
curved sheet metal, with no sides. The front fenders may not be legal
for street use.
Anybody familiar with the original Laguna Seca race track logo? I
really like that body style and I could place a body like that on a
proven Lotus type frame. Still, it's an open cockpit car and I really
think I need a roof. Doors too.
I know doors complicate things as far as torsional rigidity go, but
that can be worked around. A high sill is a problem for me because I
have vertigo now and have had it for about 35 years. Standing on one
leg to climb into or out of car could be problematical. At least I no
longer fall out of chairs.
I have decided that I want from 120 to 140 HP. That will be plenty
to make a really light car zippy. Especially if the engine is already
zippy. I like the look of carbureted engines and really like SU carbs.
But I don't know if I want the hassle of dealing with carbs. BUT WTF,
my tractors have carbs and they all start and run pretty reliably as
long as I use ethanol free fuel, even after sitting for months during
the winter. I also like multiple carbs with velocity stacks. 4
cylinders, 4 carbs. Even if nobody can see them under the hood I'll
know they are there.
I guess I'll need to take a class to learn how to shape sheet metal
for the body. There are at least two places on the west coast that
offer classes. Probably be a bunch of young guys with sharp minds in
the classes too that can teach me some stuff.
I have the machine shop but not the sheet metal shop. So I will
either need to build another shop or rent one for a while. I have the
machining and welding skills but my sheet metal working skill set is
pretty lacking so the class will be fun.
If anybody wants to give me any input I'll gladly accept it. I have
two years to figure out just what the car will look like, what the
power train will be, and what the frame should be like. Or at least an
outline of it all. I'm excited.
Cheers,
Eric

Hi Eric. It sounds like you've been bitten by a bug that never stops until it's eaten you up. g I've been there; I have an original edition of Costin and Phipps book, and a contemporary that I bought in 1961 -- _Sports Car Bodywork_ by Locke. Over the years I've built a near-bookshelf of bodywork, chassis, and engine sports-car and race car books.

I've helped out on two such projects by others, neither one completed. I'll suggest that it's 5 to 10 times as much work as most people, even experienced metalworking people, think.

You probably don't want to hear this, but my suggestion is to buy a good kit car that you like and build that. There will be plenty of work to do, for a year or more, typically. If you're really lucky, you'll find one that someone half-completed before they gave up. Those toys have left broken marriages behind. It's sTILL much more work than most people realize.

I've gone to great lengths to try things -- hammering aluminum, welding 4130 tube, and so on. When I did some sports car racing in the late '60s and early '70s, I rebuilt two Alfa Romeo engines, and tuned Jaguars, Triumphs, hot English Fords, and Bristols (AC Bristol cars) for my sporty-car friends. I had an excellent English mechanic for a friend and teacher. Out of college I first worked for Ranger Yachts, as a fiberglass layup man. It's MUCH easier to learn than hammering aluminum.

I raced an Alfa Romeo Giulietta Spyder, an MG Midget 1275, and I drove or owned many others. My old college roommate still has one of the 50 Lotus 7 Mk IVs that were brought into the US in 1971. I've driven it; even though it's the most advanced chassis in the Lotus 7 series, it's still twitchy. My MG was more stable. Suspension and handling are exceedingly tricky on a scratch-built car. That's why many of the English club-racer specials took the suspension parts wholesale from some proven car. The Triumph Herald was a favorite.

Carbs are manageable. There is a good book on tuning SU's that I used to use. I've tuned Weber DCOEs for hopped-up engines, and sliding-throat Zeniths.. Just read what the experts say. SU's, particularly, have so many combinations of main jets and needles that you'll be completely lost, if your engine has even the slightest modifications, without a good book. There aren't many "experts" left to call upon. IIRC, Clare here on the NG should be able to steer you to info sources.

Good luck. I'd love to see some beginner tackle a start-to-finish sports car and succeed. Something really simple, like Champion's Locost, gives the best chance of pulling it off. Beyond that, it becomes distressingly complicated and frustrating.

--
Ed Huntress