1 Steam Cars : Phorum
General Steam Car topics
1974 Saab Steam Car
Posted by: Peter Brow (IP Logged)
Date: April 23, 2002 04:54AM
<HTML>Peter Heid loaned me a copy of the December, 1974 Popular Science, with an interesting article on the experimental steam car which Saab was working on at the time. Incredible design; an electronically-controlled 28-lb multipath boiler with 1mm bore tubing and 16 gph firing rate intended to run an engine at 160 hp, hermetically sealed water system, etc..
I have serious doubts about the cost, fabrication difficulty, and practicality of most of the components, especially the tiny 3000 rpm 9-cylinder SA unaflow swash-plate expander, and am not currently planning on building anything remotely similar.
However, I wonder if anyone has any information or knowledge about this intriguing system, especially if Saab ever got it running on the road, how many miles they put on it, test results, why it was roundfiled, etc..
This Popular Science article is the only specific info on the system which I have seen, other than vague references to the system here and there. It seems to have pretty much disappeared off the face of the earth.
Peter</HTML>
I have serious doubts about the cost, fabrication difficulty, and practicality of most of the components, especially the tiny 3000 rpm 9-cylinder SA unaflow swash-plate expander, and am not currently planning on building anything remotely similar.
However, I wonder if anyone has any information or knowledge about this intriguing system, especially if Saab ever got it running on the road, how many miles they put on it, test results, why it was roundfiled, etc..
This Popular Science article is the only specific info on the system which I have seen, other than vague references to the system here and there. It seems to have pretty much disappeared off the face of the earth.
Peter</HTML>
Re: 1974 Saab Steam Car
Posted by: Jim Crank (IP Logged)
Date: April 23, 2002 12:26PM
<HTML>Peter,
Strange you mention the Saab steam car project. Popular Science and the rest of those magazines in those days never got beyond the gee whiz aspect of steam cars. Shallow reporting as usual.
I have been recently talking to the designer of the car and an old friend, Dr. Ove Platel, now retired. He visited me when I was making the steam race car and we had a wonderful time together. He has a wonderful sense of humor.
The car was never completed beyond testing the new condenser design. The engine was most unique and if you noticed, it had a conical rotary valve, made of pure boron nitride.
Swash plate/wobble plate designs are most interesting when you are trying to compact the engine to fit a chassis; but the swash plate has lubrication problems with high loading and the wobble plate had bad cyclic loading of the plate bearings unless it is really massive. It has possibilities; but needs serious stress analysis.
The super multi path steam generator would never have worked. How do you make sure each circuit had water flow? Also count on using triple distilled water with an inhibitor added. Just think of what cylinder oil would have done to this steam generator design!!
I have a very nice and detailed booklet that Saab put out at the time with color overlays and everything. Should you visit some time, we could go over it.
Don't get me wrong, there was some superb thinking in this proposed steam car. It just seems to me that they were trying to do too many new things at once.
Dr. Platel has the car in his garage and is thinking of completing the project some time, and I encouraged him to do so.
Jim</HTML>
Strange you mention the Saab steam car project. Popular Science and the rest of those magazines in those days never got beyond the gee whiz aspect of steam cars. Shallow reporting as usual.
I have been recently talking to the designer of the car and an old friend, Dr. Ove Platel, now retired. He visited me when I was making the steam race car and we had a wonderful time together. He has a wonderful sense of humor.
The car was never completed beyond testing the new condenser design. The engine was most unique and if you noticed, it had a conical rotary valve, made of pure boron nitride.
Swash plate/wobble plate designs are most interesting when you are trying to compact the engine to fit a chassis; but the swash plate has lubrication problems with high loading and the wobble plate had bad cyclic loading of the plate bearings unless it is really massive. It has possibilities; but needs serious stress analysis.
The super multi path steam generator would never have worked. How do you make sure each circuit had water flow? Also count on using triple distilled water with an inhibitor added. Just think of what cylinder oil would have done to this steam generator design!!
I have a very nice and detailed booklet that Saab put out at the time with color overlays and everything. Should you visit some time, we could go over it.
Don't get me wrong, there was some superb thinking in this proposed steam car. It just seems to me that they were trying to do too many new things at once.
Dr. Platel has the car in his garage and is thinking of completing the project some time, and I encouraged him to do so.
Jim</HTML>
Re: 1974 Saab Steam Car
Posted by: Peter Brow (IP Logged)
Date: April 24, 2002 05:46AM
<HTML>Hi Jim,
Thanks for the interesting info and insights; agree on your assessment of the design. One of these days I will head north and take a look at the booklet, etc. Yes, the popular press does tend to take a "gee whiz" approach to new technology, sort of like their approach to hybrid, hydrogen, and fuel cell cars today.
The details in the article were so sketchy that I wasn't sure that was a rotary valve in the drawing, but that seems to fit. Kind of disappointing. But maybe with advanced ceramics, precise machining, the valve perfectly mechanically located in the center of the bore, and port geometry designed around the inevitable leakage ...
Wobble and swash plate designs are an area I haven't gotten too deeply into. Just a cursory glance shows that there are all kinds of problems to be worked out, though reportedly there are automotive a/c compressors which run successfully on this principle. I'll stick with crankshaft drive for now, though a friend has offered to give me a disassembled Wankel for possible conversion.
I have some ideas for balancing flow in a multipath once-through steam generator, but for 120 paths it gets pretty hairy. Actually, the PS article said 120, but from some eyeball scaling of the drawing and quick math I think it was 40 paths, with 3 coils per path (water heating on outside, generating nearest fire, and shielded superheater between). Similar to the SES generator. Though only 40 paths would give pretty shrimpy combined flowpath area in the steam sections. Then again, the figures seem to assume a pretty low steam rate for the expander.
Plus there seem to be 2 manifolds with thermocouples(?) to combine the paths between sections. I might be wrong about that; just some guesstimates based on the sketchy info in the article. And, with carbon buildup, etc it would be a really monumental job to get or keep this thing running. Maybe they could control carbon by using parallel flow in the fire-side generator section, so that the "dry point" in those tubes is well away from fire. That, plus assuming the hermetic sealing worked, plus instantaneous (article sez electronic) fire/water control. Who knows.
I was _this close_ to asking about this steam car while visiting the Saab Museum in Trollhattan, Sweden last summer, but at the last minute decided not to, due to time constraints. Wonder if they would have referred me to Dr. Platel. I hope he gets this car running, though I wonder how many design changes he'll have to make in the process.
The condenser and steam generator were the main things of interest in this system. The condenser, which the PS article says has 4 times the (inner?) surface area of a standard radiator of the same size, is an excellent design, but doesn't look very home-shop-buildable. Any info on how the Saab condenser tests turned out?
Peter</HTML>
Thanks for the interesting info and insights; agree on your assessment of the design. One of these days I will head north and take a look at the booklet, etc. Yes, the popular press does tend to take a "gee whiz" approach to new technology, sort of like their approach to hybrid, hydrogen, and fuel cell cars today.
The details in the article were so sketchy that I wasn't sure that was a rotary valve in the drawing, but that seems to fit. Kind of disappointing. But maybe with advanced ceramics, precise machining, the valve perfectly mechanically located in the center of the bore, and port geometry designed around the inevitable leakage ...
Wobble and swash plate designs are an area I haven't gotten too deeply into. Just a cursory glance shows that there are all kinds of problems to be worked out, though reportedly there are automotive a/c compressors which run successfully on this principle. I'll stick with crankshaft drive for now, though a friend has offered to give me a disassembled Wankel for possible conversion.
I have some ideas for balancing flow in a multipath once-through steam generator, but for 120 paths it gets pretty hairy. Actually, the PS article said 120, but from some eyeball scaling of the drawing and quick math I think it was 40 paths, with 3 coils per path (water heating on outside, generating nearest fire, and shielded superheater between). Similar to the SES generator. Though only 40 paths would give pretty shrimpy combined flowpath area in the steam sections. Then again, the figures seem to assume a pretty low steam rate for the expander.
Plus there seem to be 2 manifolds with thermocouples(?) to combine the paths between sections. I might be wrong about that; just some guesstimates based on the sketchy info in the article. And, with carbon buildup, etc it would be a really monumental job to get or keep this thing running. Maybe they could control carbon by using parallel flow in the fire-side generator section, so that the "dry point" in those tubes is well away from fire. That, plus assuming the hermetic sealing worked, plus instantaneous (article sez electronic) fire/water control. Who knows.
I was _this close_ to asking about this steam car while visiting the Saab Museum in Trollhattan, Sweden last summer, but at the last minute decided not to, due to time constraints. Wonder if they would have referred me to Dr. Platel. I hope he gets this car running, though I wonder how many design changes he'll have to make in the process.
The condenser and steam generator were the main things of interest in this system. The condenser, which the PS article says has 4 times the (inner?) surface area of a standard radiator of the same size, is an excellent design, but doesn't look very home-shop-buildable. Any info on how the Saab condenser tests turned out?
Peter</HTML>
Re: 1974 Saab Steam Car
Posted by: David K. Nergaard (IP Logged)
Date: April 24, 2002 10:04AM
<HTML>There is an SAE artical on the subject, paper #760344, written by Ove Platell. I have a Xerograph in my collection. I would like to have a copy of the paper Jim Crank mentioned, even if only a B&W Xerograph. Would a swap work?</HTML>
Re: 1974 Saab Steam Car
Posted by: Jim Crank (IP Logged)
Date: April 24, 2002 01:58PM
<HTML>Hi Peter and David,
Ove was convinced that the boron nitride rotary valve would work, because of the self lubricating properties; but I am still questioning the loading from steam pressure and the wear factor. Not an easy design.
Wobble/swash plate car air conditioning compressors are common. G.M used them for decades. I have a big one on my bench to dismantle and look at, I like real hardware as a study item when I am thinking about a new car. Hence the Wankel, Lysholm and that compressor on the shelf for study purposes.
I personally have little hope for that steam generator, balancing flow in so many tiny tubes is just not practical. Carbon and scale would be my reasons for never trying such a design, although you can see that they wanted super heat transfer in the smallest package.
The condenser was a really good idea and certainly did have large area for the size; but you would have to make custom tooling to bend the metal into that shape. Maybe??
David, let me fix a problem with the Doble cutoff pedal first then I will see if I can get good copies of the promotional booklet.
The dog on the quadrant won't engage, a spring problem. I need to fix that right away, as I need the car for several events real soon.
Jim</HTML>
Ove was convinced that the boron nitride rotary valve would work, because of the self lubricating properties; but I am still questioning the loading from steam pressure and the wear factor. Not an easy design.
Wobble/swash plate car air conditioning compressors are common. G.M used them for decades. I have a big one on my bench to dismantle and look at, I like real hardware as a study item when I am thinking about a new car. Hence the Wankel, Lysholm and that compressor on the shelf for study purposes.
I personally have little hope for that steam generator, balancing flow in so many tiny tubes is just not practical. Carbon and scale would be my reasons for never trying such a design, although you can see that they wanted super heat transfer in the smallest package.
The condenser was a really good idea and certainly did have large area for the size; but you would have to make custom tooling to bend the metal into that shape. Maybe??
David, let me fix a problem with the Doble cutoff pedal first then I will see if I can get good copies of the promotional booklet.
The dog on the quadrant won't engage, a spring problem. I need to fix that right away, as I need the car for several events real soon.
Jim</HTML>
Re: 1974 Saab Steam Car
Posted by: Peter Brow (IP Logged)
Date: April 25, 2002 07:05AM
<HTML>Hi Jim,
On that rotary valve, the material might take it, but I wouldn't trust the sealing surfaces to take all the mechanical loads. I'm not sure exactly how the valve is designed, as the drawing I have doesn't show many details. Rotary steam valves don't have a good track record, to put it mildly.
40-120 tiny paths is too many to deal with. I wouldn't even consider more than a dozen, except maybe with a circulating pump as envisioned for Jerry People's SPAT steam generator. For a once-through multipath, I think the end of the generating zone, and the superheater, would have to be kept in a final radiant monotube section, at least 2-3 coils, downline from a plenum. The multiple paths (like finned tubing) should only be in the convective zone, no radiant heat, and should have horizontal radial symmetry, all exactly the same length & shape, plenums (plena?) and gas flow passages too.
1 mm tube bore is just too small, and the resulting ultralight tube stack would be a bear to control under varying loads -- strictly microprocessor territory, a serious programming project, and maybe a terabyte hard drive. :) A Stanley boiler isn't necessary, but I think good performance requires at least _some_ stored energy under the hood. Another plus for the Lamont.
The Saab condenser design looks doable for a production vehicle, but probably more work than it's worth for a one-off or prototype (buy junkyard radiators instead). In production, some of the header work could be injection-molded hi-temp plastics, as used in today's aluminum radiators. I repaired a crack/leak in one of those plastic radiator headers with epoxy resin and fiberglass cloth, and it ran fine for a couple years of hard use until the owner moved to Arizona in the summer. I never did find out if it failed at the repair, or elsewhere. But maybe the headers in a Saab-type condenser could be made of epoxy/fiberglass composite, if the fiber/cloth layup & molding could be worked out?
Nothing beats "take it apart and study it" work. My shop is full of compressors, engines, and other mechanisms which I took apart to study. One interesting item was an A.I.R. pump from a '74 VW bus smog system. This was a vane-type compressor with the inner ends of the vanes supported by roller bearings on an eccentric shaft (that was nearly 20 years ago, & I don't remember all the details).
I think the vane tips operated with slight clearance in the housing, and at the time I wondered about the possibility of building an all-metal version with seal strips along the pressurized edges of the vanes. Centrifugal force would only load the seal strips, while the large vanes would allow more displacement volume for a given unit volume (and surface area).
Some vane-type rotary engines try to do the same friction/wear-reduction thing with very small one-piece vanes, but these units end up much larger for a given displacement.
Speaking of which, did you ever look into the Hinckley-Beloit rotary steam engine? I just came across an article in Vol. 14, #1 (1972) of The Steam Automobile (pp. 4-5) about this. Developer (John Hinckley) claimed lower surface-to-volume ratio than either Wankels or piston engines (an amazing claim, IMO). I wonder if he ever patented it. Of course, Wankels have already had billions in R&D put into the seals, which are the hard (& crucial) part of any rotary design. At the time of this article, Hinckley was only beginning tests for hi-temp steam seals.
Peter</HTML>
On that rotary valve, the material might take it, but I wouldn't trust the sealing surfaces to take all the mechanical loads. I'm not sure exactly how the valve is designed, as the drawing I have doesn't show many details. Rotary steam valves don't have a good track record, to put it mildly.
40-120 tiny paths is too many to deal with. I wouldn't even consider more than a dozen, except maybe with a circulating pump as envisioned for Jerry People's SPAT steam generator. For a once-through multipath, I think the end of the generating zone, and the superheater, would have to be kept in a final radiant monotube section, at least 2-3 coils, downline from a plenum. The multiple paths (like finned tubing) should only be in the convective zone, no radiant heat, and should have horizontal radial symmetry, all exactly the same length & shape, plenums (plena?) and gas flow passages too.
1 mm tube bore is just too small, and the resulting ultralight tube stack would be a bear to control under varying loads -- strictly microprocessor territory, a serious programming project, and maybe a terabyte hard drive. :) A Stanley boiler isn't necessary, but I think good performance requires at least _some_ stored energy under the hood. Another plus for the Lamont.
The Saab condenser design looks doable for a production vehicle, but probably more work than it's worth for a one-off or prototype (buy junkyard radiators instead). In production, some of the header work could be injection-molded hi-temp plastics, as used in today's aluminum radiators. I repaired a crack/leak in one of those plastic radiator headers with epoxy resin and fiberglass cloth, and it ran fine for a couple years of hard use until the owner moved to Arizona in the summer. I never did find out if it failed at the repair, or elsewhere. But maybe the headers in a Saab-type condenser could be made of epoxy/fiberglass composite, if the fiber/cloth layup & molding could be worked out?
Nothing beats "take it apart and study it" work. My shop is full of compressors, engines, and other mechanisms which I took apart to study. One interesting item was an A.I.R. pump from a '74 VW bus smog system. This was a vane-type compressor with the inner ends of the vanes supported by roller bearings on an eccentric shaft (that was nearly 20 years ago, & I don't remember all the details).
I think the vane tips operated with slight clearance in the housing, and at the time I wondered about the possibility of building an all-metal version with seal strips along the pressurized edges of the vanes. Centrifugal force would only load the seal strips, while the large vanes would allow more displacement volume for a given unit volume (and surface area).
Some vane-type rotary engines try to do the same friction/wear-reduction thing with very small one-piece vanes, but these units end up much larger for a given displacement.
Speaking of which, did you ever look into the Hinckley-Beloit rotary steam engine? I just came across an article in Vol. 14, #1 (1972) of The Steam Automobile (pp. 4-5) about this. Developer (John Hinckley) claimed lower surface-to-volume ratio than either Wankels or piston engines (an amazing claim, IMO). I wonder if he ever patented it. Of course, Wankels have already had billions in R&D put into the seals, which are the hard (& crucial) part of any rotary design. At the time of this article, Hinckley was only beginning tests for hi-temp steam seals.
Peter</HTML>
Re: 1974 Saab Steam Car
Posted by: Jim Crank (IP Logged)
Date: April 25, 2002 01:14PM
<HTML>Morning Peter,
I had very serious doubts about wear in the Saab valve too. If I recall correctly, it was just a tapered plug type valve. Not overly encouraging. Have to find all that stuff Ove gave me when he visited.
Multi Circuits: The Lear steam generator I had in the race car was square with all finned 321 SS tubes all going to headers at each end and furnace brazed in a hydrogen atmosphere. 16 in parallel for the wet end, then something like 12 in the boiling and wet part, then 8 in the saturated part and finally down to one without fins in the last two banks and the superheater. They wanted a velocity match to the heat transfer rate at the specific points along the path, so I was told. Problem was that they, along with others, thought they could control the water level in a flash generator, when in reality that ability just does not exist. Lears just didn't know steam cars. Academics and no practical experience.
Couldn't tell them anything, so I just kept my mouth shut and watched them fail. I used it with a normalizer, per Doble practice, and it worked just fine. 5500 lbs/hr @ 1200 psi and 1100°F. 56 gph burn rate of JP-A.
The Lamont is the real answer in all respects.
The Yuba tractor had a neat way of handling parallel flow, they used a five cylinder swashplate water pump made from some bus air conditioning compressor and each pump fed it's own circuit, then down to one tube in the boiling and saturate zones. That worked.
Personally, I would use maybe no more than three or four in the economizer end where it counts and two in the boiling zone and into the Lamont drum. No more than two in the Lamont coil and one in the superheater.
1mm tubing is simply not realistic by any means. I know why they wanted this; but it just is not doable.
The condenser was a neat idea; but like you, I will use custom aluminum finned tube cores, with maybe 12 fins per inch.
Also have a VW air pump in my junk box, a Roots blower!! Want a supercharged lawnmower, this is the right blower. A Briggs & Stratton SSK.
Don't recall the Hinckley engine right now; but am studying that Rand-Cam engine; but it has so much friction and leak paths in it, I can't see any use as a steam engine.
The Mazda three rotor Wankel is available and while I have to modify it, I sure don't have to build it from scratch. Never build what you can buy off the shelf.
Jim</HTML>
I had very serious doubts about wear in the Saab valve too. If I recall correctly, it was just a tapered plug type valve. Not overly encouraging. Have to find all that stuff Ove gave me when he visited.
Multi Circuits: The Lear steam generator I had in the race car was square with all finned 321 SS tubes all going to headers at each end and furnace brazed in a hydrogen atmosphere. 16 in parallel for the wet end, then something like 12 in the boiling and wet part, then 8 in the saturated part and finally down to one without fins in the last two banks and the superheater. They wanted a velocity match to the heat transfer rate at the specific points along the path, so I was told. Problem was that they, along with others, thought they could control the water level in a flash generator, when in reality that ability just does not exist. Lears just didn't know steam cars. Academics and no practical experience.
Couldn't tell them anything, so I just kept my mouth shut and watched them fail. I used it with a normalizer, per Doble practice, and it worked just fine. 5500 lbs/hr @ 1200 psi and 1100°F. 56 gph burn rate of JP-A.
The Lamont is the real answer in all respects.
The Yuba tractor had a neat way of handling parallel flow, they used a five cylinder swashplate water pump made from some bus air conditioning compressor and each pump fed it's own circuit, then down to one tube in the boiling and saturate zones. That worked.
Personally, I would use maybe no more than three or four in the economizer end where it counts and two in the boiling zone and into the Lamont drum. No more than two in the Lamont coil and one in the superheater.
1mm tubing is simply not realistic by any means. I know why they wanted this; but it just is not doable.
The condenser was a neat idea; but like you, I will use custom aluminum finned tube cores, with maybe 12 fins per inch.
Also have a VW air pump in my junk box, a Roots blower!! Want a supercharged lawnmower, this is the right blower. A Briggs & Stratton SSK.
Don't recall the Hinckley engine right now; but am studying that Rand-Cam engine; but it has so much friction and leak paths in it, I can't see any use as a steam engine.
The Mazda three rotor Wankel is available and while I have to modify it, I sure don't have to build it from scratch. Never build what you can buy off the shelf.
Jim</HTML>
Re: 1974 Saab Steam Car
Posted by: Peter Heid (IP Logged)
Date: April 26, 2002 12:13PM
<HTML>Jim,
They have chain drive superchargers for Briggs & Stratton powered go carts. Believe it or not.
Peter Heid</HTML>
They have chain drive superchargers for Briggs & Stratton powered go carts. Believe it or not.
Peter Heid</HTML>
Re: 1974 Saab Steam Car
Posted by: Jim Crank (IP Logged)
Date: April 30, 2002 09:01PM
<HTML>Peter,
I would like to look into the superchargers for B & s engines. Roots blowers make dandy vacuum pumps for steam cars. It's hard to find a small one.
Can you give me the source and many their e-mail or web site address?
Jim</HTML>
I would like to look into the superchargers for B & s engines. Roots blowers make dandy vacuum pumps for steam cars. It's hard to find a small one.
Can you give me the source and many their e-mail or web site address?
Jim</HTML>
Re: 1974 Saab Steam Car
Posted by: Mark Stacey (IP Logged)
Date: April 30, 2002 09:53PM
<HTML>Hi Jim
[www.hscsupercharger.com]
is the URL for a company offering mini roots blowers fof B&S engines. This may be the one Peter meant.
Cheers
Mark Stacey</HTML>
[www.hscsupercharger.com]
is the URL for a company offering mini roots blowers fof B&S engines. This may be the one Peter meant.
Cheers
Mark Stacey</HTML>
Re: Useless? info,,,
Posted by: C Benson (IP Logged)
Date: April 30, 2002 10:22PM
<HTML>I once had a roots aircraft cabin blower , all alloy , about rite for a Vincent 1000 , well made /no name ,,,Cheers Ben</HTML>
Re: 1974 Saab Steam Car
Posted by: Jim Crank (IP Logged)
Date: May 01, 2002 01:36PM
<HTML>Mark,
The Goggle search engine says it does not know this address.
Jim</HTML>
The Goggle search engine says it does not know this address.
Jim</HTML>
Re: Roots blower
Posted by: Mark Stacey (IP Logged)
Date: May 01, 2002 06:31PM
<HTML>Hmm
Not sure why it didn't open I've just cut and pasted the URL from my message into Internet Explorer address and that worked. Full name is the Hansen Supercharger Corporation and that comes up via Google.
Cheers
Mark Stacey</HTML>
Not sure why it didn't open I've just cut and pasted the URL from my message into Internet Explorer address and that worked. Full name is the Hansen Supercharger Corporation and that comes up via Google.
Cheers
Mark Stacey</HTML>
Re: Roots blower
Posted by: Jim Crank (IP Logged)
Date: May 01, 2002 07:22PM
<HTML>Mark,
I found them, it helps if you don't put in the wrong wording!!
Neat blower, asked for a price on the bare blower without all the extra stuff. Will buy one for use as the vacuum pump.
Thanks for the help.
Jim</HTML>
I found them, it helps if you don't put in the wrong wording!!
Neat blower, asked for a price on the bare blower without all the extra stuff. Will buy one for use as the vacuum pump.
Thanks for the help.
Jim</HTML>
Re: Roots blower
Posted by: Peter Heid (IP Logged)
Date: May 02, 2002 06:20PM
<HTML>Jim,
That is the blower company I had been thinking of, glad someone remembered the name. I would be interested in hearing of your results with it.
Peter Heid</HTML>
That is the blower company I had been thinking of, glad someone remembered the name. I would be interested in hearing of your results with it.
Peter Heid</HTML>
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