This is old, but I figured it was still of interest. From: http://moes-garage.spaces.live.com/blog/cns!4FC3316B3CBDCA99!3749.entry?wa=wsignin1.0&sa=661102350 ~Jason The Worlds Most Expensive Stromberg 97 I thought You guys would find these pics (never before seen on the www) and accompaning text interesting.. Take a close look at these pics of what appears to be a 'Plastic' Stromberg 97 carb.. OK, Here's the story... These images were sent to me by Clive Prew in June of 2004 while he was still in the development stage of what would soon become the all new Stromberg 97's. He was not interested in selling or giving away the delicate Prototype but he was willing to send some early prototype pics. The New 97s have been out for several years now so there is no danger of giving away any patented or prototype 'trade' secrets regarding just how the new 97's were prototyped or 'rebuilt'.. These polyresin carbs were built using what's called the SLA or Stereolithography prototyping process... SLA or Stereolithography is a prototyping process that produces a solid 3-dimensional object in a vat of liquid resin using a computer controlled/motorized lazer beam. The lazer is positioned and controlled Via computer from a 3D CAD file of the particular object to be built. -The Computer positions the Laser head and the laser beam heats/cures the object as it slowly descends one slice at a time into the vat of liquid photopolymer or resin. Photopolymer is a similar to film for a 35mm camera in that " Light" imprints or cures on the "Film". But In this case, the 'Light' happens to be a Laser and the 'Film' happens to be a liquid.... That said, The actual laser beam will not penetrate down into the vat of liquid photopolymer more than a few thousands of an inch with each step so Clive's New See Thru Stromberg 97's had to be built by 'developing' many thousands of 3D 'photographs', stacked and fused, one on top of the other to form the Actual 3D Prototype Carb. The Laser follows the 3d cad design exactly and very accurately from a 90 degree position over top of the liquid vat. The object is 'burnt' one layer at a time as the elevator lowers the part into the vat while the laser traces out whatevers programmened into the cad file. The layers can be described as similar to a deck of cards... One layer is stacked on top of the next.... the layer below cools while the elevator drops and the object is lowered a few thousands of an inch (into the vat of resin). The process is then repeated. ..Once the object has fully descended into the vat and the laser has cured it's last actual 'slice', the object is carefully raised from the tank and emptied of any liquid resin then it's off to the infared oven for cureing. The resins for this process are about $800 per gallon which translates to fairly expensive prototyping. I thought I would share these neat pics... I believe that these two particular polyresin images have not been posted anywhere on the www before. The images are also fairly low res compared to the originals (for obvious reasons ). Clive still holds the copyrights to the 3D CAD design that made this Resin Prototype and the subsequent new Stromberg 97's. It is interesting to note that this resin carb is actually capable of metering fluid and air into a proportional and accurate "fuel to air" ratio. The SLA process is accurate to .003 inches so even the threads of a small screw hole are accurate to the original item which is scanned into the cad file by a laser beam. The pics were taken on the day that Clive returned to his office with the prototype freshly cured and out of the oven. Clive was in the midst of carefully assembling the delicate Stromberg 97 with the appropriate hardware/fittings/screws/parts that would eventually be used on the forthcoming -all new- Stomberg 97's. Clive Prew had to jump through more than a few hoops in reverse engineering the original Stromberg 97s. I do recall that the ball end of the throttle and/or choke actuating levers presented their own unique problems. The sweat was in the details all of which is history now. ....moe . . . A Tip of the Hat goes to Flathead Youngin' for the neat Stromberg 97 Cutaway Pictures
StereoLithography is cool. We had the number 16 machine (SLA 250) at General Dynamics and I represented the Advanced Design interest in the technology. Later, I was involved in Valeo climate control's SLA 500 purchase and setup. It can be complex and expensive... my job was to make it practical. I left before finding out what they really wanted. I wonder how they are doing now? Are they making parts? Or are they still doing demos like this way cool carb? himmelberg
I've never held one... on the outside, Clive and them did a great job, but I'm curious as to what "a few key improvements" means (per http://www.stromberg-97.com/ ) What DID they fix, Max? ~Jason
Wow, that plastic prototype is really incredible! Here is an old cutaway that was made up in the Stromberg shop.
I knew people pounded on the tops of 'em, but that went right through! LOL! That's wicked-cool, man! Wouldn't a top like that be KILLER if that hole in the top had a beveled edge and some glass permanently sunk into it with a sort of mini-windshield gasket? You could sure as hell see if your float was F'd, that's for sure! I've built a few Hitachis that had a window in the side of the bowl, with a dot in the middle so you knew if the float was at the right level or not by the level of fuel in the bowl... ~Jason
It's neat what technology has brought us. I think that the system the Leno uses (as mentioned above) uses solid plastics rather than poly resins like the sla system used to copy the 97's
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