Bugatti: Aero Beauty and Innovation - Page 5 - Fuel Economy, Hypermiling, EcoModding News and Forum

gone-ot · 03-13-2010, 04:26 PM

Quote:

Originally Posted by Christ

The trolls have been fed.

...ah, the trolls have been sated, but have they been sedated?

orange4boy · 03-13-2010, 05:41 PM

One of the reasons I'm so interested in this car is that it is a very early effort at the "ideal shape"

I wonder if Ettore thought of adding a canvas cover over the cockpit as I've seen on other convertibles? It would have cooked the driver and mechanic though.

The other fix: Boatail helmets.

I imagine there might have been some vortex action off the square front edges depending on the aspect ratio. Anyone know the optimal ratio at which you get the least spillage?

The later 1936 type 57 S is a much softer "tank" with a much smaller cockpit. This is the same car that won the 24 hours of Le Mans in 1937 Which set a new track record average speed of 137KPH

Low Cd anyone?

orange4boy · 03-13-2010, 06:21 PM

Quote:

Originally Posted by aerohead

I've been spending time with Jaray's development model and I am convinced that even in separated flow,the aft-body still performs a beneficial function.
Without a technical term to draw on,I'm refering to it as 'stuffing the wake.'
And it's a concept aerodynamacists stumbled onto when testing convertibles with the top down.
By placing manikins in the open car they were able to measure lower drag do to this 'stuffing,' and I think that the aft-body of the Bugatti 'tank' is helping to perform this function.
All,except the last of Jaray's models( the full-tail) suffer separated flow very early on the body but do not suffer the drag as would occur at the same point for a Kamm chop,so the tail must serve drag reduction even though it's less than ideal.I believe it's true of all pseudo-fast-back cars.

That's interesting because I was comparing the type 57 SC rear angles and the Tatra T77's and they look very similar. I thought the Tatara's looked much steeper that the template and the max angles stated in Hucho. The aspect ratio of the cab is very different though and the 57 has all those fenders and grilles going on.

wdb · 03-14-2010, 01:30 PM

Quote:

Originally Posted by orange4boy

I found a shot that shows a bit of the belly pan on the T-32 The salient question on this car is whether the air would reattach behind the cockpit.

The salient question to me is, how did anyone manage to drive that thing at racing speeds? Slab sides, full belly pan with no splitter or air dam to limit under-car airflow (a mistake that was still being made in race car design as late as the 1960's), those have to be a recipe for getting pushed around in all the wrong ways by the airstream. Couple that with an incredibly short wheelbase and -- well, let's just say my leather helmet goes off to anyone who drove that at racing speed.

And lest anyone think those speeds were low:

thatguitarguy · 03-14-2010, 02:39 PM

Hermie would have a field day raving about the lift of a car that's shaped like the cross section of an airplane wing.

orange4boy · 03-14-2010, 05:49 PM

Quote:

And lest anyone think those speeds were low:

LOL, I think that picture is misleading. I don't mean to jump all over you here but just looking carefully, the frontwards skew is either a lens aberration or a darkroom trick. If we knew the shutter speed, we could figure out the speed it was travelling. Just guessing using the specs from a Graflex of 1923 with a max shutter speed of 1/1000 s. If the shutter speed was 1/500 s and the blurr was about 2 inches then it would have been going 60 mph. At 1/1000 s the blur would have been 1" It looks less than that to my eyes.

Obviously, I have way too much time on my hands.

Since two of them are still racing in vintage days, it would be interesting to hear from those drivers. From what I've gleaned so far the top speed was about 117 mph and the average track speed was probably half that at best. Although lift would have probably had some negative effects, a lot of the weight on these cars is between the front wheels where most of the lift would be and it has been pointed out ad nauseum in other threads, at speeds below 100mph, lift is pretty much a minor issue. The short wheel base would probably have been it's real downfall.

One advantage in cornering is that the car would have had a much lower centre of gravity than the cars it was racing against which were very easy to rollover. This was probably offset by the twitchyness which would have been murder on the relatively rough tracks they drove on in those days.

Having said all that, which is just my side seat driver opinion, I agree that these cars would have been a hand full to race!

I think if Bugatti had stuck with that overall design and tweaked it, he would have dominated racing even more than he did with the type 35. As it is, 14 years later, he won both the 1937 and 1939 24 hours of Le Mans in the more rounded edge but longer wing shape type 57 S and a 57 G respectively. Each set a Le Mans record for average speed in the mid to high 80mph

Since his main goal was to sell the cars he raced, I bet he took the negative reaction to the shape to be a marketing problem and returned to making fantastic engines for the more normal looking type 35. Fuel economy would not have been a factor to Bugatti or the wealthy who bought his cars.

I couldn't find the exact cars but this is a replica of the car that came in second at the 1937 Le Mans.

And a restored version of second place in the 1939 Race:

The type 57 G

The racing version did not have had the spare tire on the back

Added. Here is a photo of the start of the 1939 race with the actual cars:

Frank Lee · 03-14-2010, 05:58 PM

Heh heh, love the ricer vents in the back!

I also love how racers in the old pics are either 4" above the ground with all four tires and/or they're going so fast the wheels aren't even round anymore! LOL