Super streamlined 7
Mr Whippy - 26/3/21 at 04:36 PM
I’ve been tyre kicking the little car lately after making great progress sorting the deficiencies of the Robin Hood chassis design. Hard to explain
but I’ve just not been happy with the final car for some reason as it just didn’t feel like what I was after. I was really wanting something different
to a 7 style car but maybe using the 7 as the chassis. Now I think I have pinned it down…
There’s one car even as a kid I loved, the 1960 CN7 Bluebird, a mad jet powered streamlined monster and one image of it got me thinking, what if I
made a shell like that for the 7? It would certainly be super slippy. Main difference would be the driving position would remain as is on the 7 rather
than the mad between the wheels location on the original.
Looks a lot of work but I’d do it the same way I’ve moulded car, kayak and model plane parts before. Just carve up blocks of white polystyrene foam to
the approximate shape. Cover in tape and lay the glass fiber over it, remove it and then simply finish off the surface with filler and paint rather
than the more expensive & time-consuming method of making patterns and moulds etc. I think also I’d be best mounting it on a pole so I could spin
it round and make the top and bottom in one piece, then slice it down the middle to remove it.
Maybe something like this... (original car below)
steve m - 26/3/21 at 04:50 PM
steering looks a bit limiting ?
But it would look cool on a drag strip
Mr Whippy - 26/3/21 at 05:56 PM
Yeah the front fender bulges would be quite a bit more pronounced than that but along the same lines.
big_wasa - 26/3/21 at 05:57 PM
Why not if it floats your boat
Ugg10 - 26/3/21 at 06:31 PM
Have a search for the Lotus 11 (XI), there have been a number of kits that use a seven-ish chassis. I think Tiger did one, Xanthos and Westfield.
Benzine - 26/3/21 at 07:11 PM
Sounds great 
my se7en is already good on diesel but this kind of thing would make it even better.
Se7en ranks worse than a hummer:
Caterham 7 drag coefficient
02GF74 - 26/3/21 at 08:37 PM
Buy the airfix model kit and make slice templates.
Scale up after adjustment for wheels, engine, occupants and transfer to foam sheets. Drill 2 holes in each sheet and put onto broom handles to
assemble then trim edges to smooth down the profile.
That should work better than randomly carving large chunks of foam.
Post photos of your progress.
Note there are less weird looking "melted cheese slice on 4 wheels" type cars than that, e.g. DBR1
And the bluebird was built at the time when engineers were beginning to understand aerodynamics, it wouldn't surprise me if the average nowadays
family hatchback has lower drag factor than it.
Mr Whippy - 26/3/21 at 11:48 PM
quote:
Originally posted by 02GF74
And the bluebird was built at the time when engineers were beginning to understand aerodynamics, it wouldn't surprise me if the average nowadays
family hatchback has lower drag factor than it.
It's an interesting point however the Tesla model S which claims to be the most aerodynamic production car has a drag coefficient of 0.208 is not
a patch on the Bluebirds 0.16. Even my leaf with its undertrays and pointy nose only manages 0.28.
There's a great table in wiki for cars, sadly the 7 actually worse than almost everything else including a truck!
wiki linky
[Edited on 26/3/21 by Mr Whippy]
Sam_68 - 27/3/21 at 08:01 AM
quote:
Originally posted by Ugg10
Have a search for the Lotus 11 (XI), there have been a number of kits that use a seven-ish chassis. I think Tiger did one, Xanthos and Westfield.
^^^ This.
I don't think Tiger or Xanthos did kits, though - that was the 23 in both cases. Westfield still sells their version.
The Lotus Eleven (not 11 or XI, if you're being anal - it was spelled out as a word) actually preceded the Lotus 7, and the S1 Seven was
basically nothing more than an Eleven with cheaper-to-manufacture (back in the days of hand-rolled aluminium) bodyshell.
The body was designed by top aerodynamicist Frank Costin, and they did an even more carefully streamlined version with a closed bubble canopy and
flush exhaust system for recordbreaking. It managed a fastest timed lap at Monza of 145.5mph on an 1100cc engine that probably wasn't producing
much more than 96bhp.
Schrodinger - 27/3/21 at 09:01 AM
Tiger do the ERA 30 which is loosely based on the Lotus 23/30 they also do the GTa which fits on the Avon chassis.