New Chassis And New M2013 Boiler
Wednesday, April 3rd, 2013: After re-examining the 1964 VW Beetle chassis ("floorpan") which I recently excavated from under a heap of boxes and bags during my garage/workshop spring cleaning, I have decided to build my steam car around the VW chassis. The main problem with using a VW chassis was fitting a Stanley-style engine in front of the rear axle. That would have required too much cutting and reinforcement work on the chassis to be worthwhile. That is what led me to my previous "hot rod style" chassis design. But after some brainstorming, I figured out a way to mount the engine on, and _behind_, the rear axle. Thus my steam car is now planned to be rear-engined, rather than mid-engined like a Stanley or Doble. This requires a different cylinder-end engine mount and slight changes to the steam plumbing and to the engine itself. These changes allow the engine to be in the rear, which gives several advantages, including the use of the easily-road-registered and already-on-hand VW chassis. The chassis is complete, with full suspension, braking, and steering systems installed. The previous owner says that everything in the chassis was working fine until the transaxle failed, which is why he sold it to me around 1988. Of course, I have no use or need for the transaxle; it will be removed. I also worked out a simple way to connect the Ford Nine Inch axle to the original VW rear trailing arms & torsion-bar rear suspension, with a Panhard rod to keep the axle centered. All of these changes will save lots of time and effort building and getting the car on the road, relative to my previous custom chassis design.
The "Old VW" suspension is lightweight, economical, and highly durable, so durable in fact that it is a popular choice for dune buggies, "Baja Bugs", and other off-road vehicles, which take a lot of abuse. In fact, this very chassis was once part of a Baja Bug. All of the parts are in aftermarket production and likely to stay that way for decades to come, and they are easily sourced and easy to work on.
The chassis itself was designed to have a body shell bolted onto it, which makes it easier to design and mount my custom body. This bolt-on body design has also made the "Old VW" Beetle chassis popular among kit-car and custom-car builders.
Mounting the boiler on top of this chassis/floorpan, at the front, is also workable, now that I have designed a more compact boiler, which I call the "M2013". This has a single central vertical standpipe, insulated from the fire, serving simultaneously as reserve, downcomer, steam/water separator, and "mud collector", with a radial array of steam-generation tubes around its lower end. This is broadly similar in principle -- but not in tube shape or layout -- to the very successful Ofeldt and Bolsover boilers of the past. These tubes will be intensely radiant-heated by the annular fire which surrounds them, and these tubes are shorter and more gradual in their bends than those in my previous boiler design, meaning that they will have less flow resistance and more rapid natural water circulation inside. Above the steam-generation tubes is a "pancake coil" economizer section, which consists of 2 parallel paths of 3/8" outer diameter steel tubing. The top of the small-diameter vertical standpipe passes up through the center of this pancake coil stack, giving a "steam dome" for good steam/water separation. There will also be a cyclone separator built-into the top of the standpipe, guaranteeing good dry steam. The "M2013" economizer is similar to the economizer in my "M2012" boiler design, which I no longer plan to build. The new "M2013" boiler will be lighter, more compact, less expensive, and far easier to build than the "M2012" boiler. It is also far simpler than the "M2012", which had multiple horizontal drums, and I designed it in a fraction of the time. The standpipe and tubes are strong enough to handle four times the pressure at which it will operate, giving a considerable margin of safety and far exceeding the already-conservative "boiler code" safety standards.
The list of things being built now includes the pilot burner, engine, and burner-warmup pilot timer, and parts now on hand include engine cylinders, engine frame, condenser, (Old VW) fuel tank, and full "roller" chassis with complete running gear, wheels, and tires. The rims are groovy 70s-vintage Empi; I am considering Moon or other new wheel covers for a cleaner and more timeless appearance.
Oddly, this is the exact same chassis which I had planned to use in my abortive 1988 steam car project, though the powerplant which I planned to use then was quite different from what I am building now. Fortunately, during that project I learned how to build modern-looking custom car bodies with sheetmetal panels bent onto a curved wood framework. The construction method was similar to the way many car bodies were built into the 1930s, and that is how many replica and replacement antique car bodies are still built today. If I had built it that way, then I would have a serviceable body now, and I would have spared myself the filthy toxic nightmare of large-panel fiberglass work. But in 1988/9 I built the body merely as a "buck" or "pattern", with 1/8" mahogany plywood covering, on which I made fiberglass molds and was planning to make fiberglass body panels. Soon afterward, I had to move, and ended up scrapping the laboriously-fabricated patterns, molds, and panels because I had no room to store them. Live and learn.
My garage/workshop spring-cleaning project is a big one -- amazing how things pile up in just a few years -- but it is well underway and major progress has been made. I expect to have the shop cleared out, ship-shape, and ready to resume major steam car construction in a couple months.
Engine Build And New Boiler Design
Thursday, May 31st, 2012: In March, 2011, I built the basic frame for my steam car engine. This is a lightweight, flexible, "4-rod" engine frame, similar to that used in the Stanley steam cars, except with thicker rods, made of "4140" alloy steel to avoid the stress breakages which occur in Stanley engines after several hundred thousand miles. My engine frame is different from the Stanley in a number of other ways; designed to make it much easier and less expensive to build and maintain.
Since then, the pistons, valves, and valve platforms have been "roughed out" of nodular/malleable iron billet, and new aircooled-VW cylinders and piston rings have been purchased.
Two changes have since been made to the engine design: the valve stem guides are now fitted with packed seals to prevent any steam or water from entering the crankcase, and the Stephenson-link valve gear now has an adjustable lock plate for easy fine-tuning of the early-cutoff "hookup" position. The latter feature should allow adjusting the engine for the very best efficiency -- even while running! Just turn a knob on the dash for earlier or later cutoff. Once this has been set, it should never need attention again.
Computer spreadsheet analysis of the boiler, in early 2012, has now led to a new and improved boiler design, which I have designated the "M2012" boiler, with several substantial improvements over the previous "M2006" boiler; primarily lower cost, lighter weight, and easier building. The boiler design principles, including short recirculating paths and natural recirculation without circulator pumps, jets, etc, are roughly the same, but now the economizer section of the boiler -- where water is pre-heated by burner gases before entering the radiant-heated evaporator section to be turned into steam -- is now two flow-paths of 3/8" diameter steel tubing. The main reason for changing to this "double-monotube" ["binotube"] economizer configuration, was better blowoff, guaranteeing a cleaner boiler. This change also positively removes all water from the boiler for cold storage, thus greatly extending the service life of the boiler. Dirty boilers, and boilers stored with water in them, don't last as long.
The previous "M2006" boiler design had 8 parallel flowpaths of 1/4" outer-diameter [OD] tubing, with radial inflow of water and radial outflow of gases; the new "M2012" boiler design has 2 parallel flowpaths of 3/8" OD tubing, with water "downflow" and hot-gas "upflow"; more in line with traditional steam car boiler design.
The new boiler is rectangular, rather than round; this also makes it easier to fit into the car, and to build. Both the water-tube arrays, and the burner too, have become easier and cheaper to build, thanks to the rectangular ["square box"] boiler shape.
Other changes to my steam car design, since my last entry here, include a standard, off-the-shelf tube-and-fin radiator instead of the previous custom condenser, and the elimination of the formerly-planned "overload-exhaust steam bubble-condensing" feature. I decided to use a radiator which I already had in my shop, for which replacement radiators are easily and inexpensively available, and in long-term aftermarket production. This radiator is designed for a high-powered V8 engine of 6 times the peak horsepower of my current steam car design, so it should be more than adequate for condensing all of my engine's exhaust steam. Generally one of the "objections" to steam cars is that they require a radiator/condenser 2 to 3 times as large as a gas car of equal developed horsepower. 6 times the radiator capacity should be more than enough!
The new standard radiator, used as an exhaust-steam "surface condenser", and the newly-simplified "no-bubbler" water tank, makes my steam car's condensing and water system much easier and less expensive to build and maintain.
Along with the above changes, I have also now nearly completed the blueprinting of the powerplant automatic control system, which promises to make my steam car as easy to operate as a conventional gasoline or diesel-engined car; easier, in fact, than a manual-transmission car, particularly the newer ones with 6 or 8 speeds.
Water Tank And Suspension Design Work
Friday, November 5th, 2010: Steam car engine frame materials were ordered and received in June 2010, but then design problems and unfinished design work elsewhere in the propulsion system and vehicle detoured me, yet again, away from the workshop. Attempts to finish the pump unit design [water, fuel, and cylinder oil pumps] led to design work on the previously-designed airscoop for the water tank cooling jacket, which occupied the same space which the pump unit needed to be in, then to a radical redesign of the water tank and its cooling and defrosting features. This "sidetrack" was frustrating at first, but has now led to a water tank which should thaw, condense overload steam, and cool down after overload-steam condensing, incredibly fast! After a long process of generating and analyzing water-tank & plumbing design options, the condenser and water tank ended up integrated in an entirely new way! The water tank is now vastly cheaper and easier to build and maintain than any of my previous designs, or any other design previously used in steam cars to my knowledge.
The new water tank and associated plumbing having now been fully blueprinted, and now ready to build, design work is proceeding on the water pump. This is a relatively standard high-pressure plunger pump unit, except for the check valves, which are of very advanced design/materials, and look very likely to increase the pump efficiency and durability by a substantial margin. As usual, fabrication, material, and component costs have been reduced far below those of conventional off-the-shelf or "prior art" steam car pump units. Besides reduced horsepower requirements, the water pump is also being designed with an automatic self-draining feature to prevent pump freezing in cold weather -- part of the "freezeproofing" system which should allow my steam cars to be started quickly from frozen-solid with no damage to any of the equipment.
The pump drive system has also now been designed, with extensive use of aluminum alloy components to substantially reduce reciprocating mass, and modern bearings to eliminate any chance of pump or pump drive noise, and to drastically extend the pump drive's service life, with minimal maintenance. The pumps are at the front of the car for short plumbing runs to boiler and for freezeproofing reasons, but are driven by the main engine at the back of the car. Designing this to be economical, easily buildable, and reliable, in a modern car, required considerable ingenuity and engineering number-crunching! Yet again the situation of "one guy doing the work of a big-automaker design team"!
Since my last entry, I have also worked out the vehicle suspension design. My research indicated that custom automobiles of the sort I am building generally have a problem with the locating/guiding of the front axle. Usually "split wishbones" or "four bar" locators are used, which have serious geometry problems and can "bind" or twist suspension components when travelling over bumps or potholes in the road. I designed a custom "one piece wishbone" or "radius-rod" locator for the front axle, operationally similar to the pre-1949 Ford suspension, but improved, which gives practically ideal front-suspension travel. No binding, no twisting, no weird suspension response over road irregularities. I got deeper into suspension research, and found that the "unsprung weight" issue is greatly overblown. Good solid-axle designs have only negligibly more unsprung weight than good independent-suspension designs [and many are not good!] for the same vehicle. The tiny difference can be crucial in racing, but it is utterly irrelevant in road driving, which is what I am designing for. Independent front suspension is really only "standard" because of space concerns with IC engine/transmission layouts in modern low-slung cars -- not an issue in my low-slung modern steam car. With a steam car, one has the luxury of "thinking outside of the box" in many ways. Anyway, my cars' suspension is now planned to be off-the-shelf solid axles front and rear, with easily-sourced, rugged, and economical transverse leaf spring [pre-1949 Ford style] in front and dual longitudinal leaf springs in rear. Panhard bars and modern "tuneable" telescopic shock absorbers on both axles, and wheels/brakes properly sized for the [light] vehicle weight. Solid-axle suspensions get a bad rap largely because of grossly oversized wheels and brakes installed in "hot rods" -- largely for cosmetic reasons. These increase the unsprung-to-sprung weight ratio far beyond reason, leading to poor ride and roadholding. Not a problem with properly-sized wheels and brakes, especially with modern lightweight wheels and disk brakes. Now, if you want foot-wide racing slicks and brake disks/drums nearly the same diameter as the tires, for "that hot high-performance look", then you have an unsprung weight problem... none for me, thanks...
One item I kept remembering during the suspension design process was the _excellent_ ride I experienced in 3 different Stanley steam cars during my trip to the UK in 2005. Smoother-riding than any modern car! And these Stanleys have solid axles and leaf springs front and rear, with the engine mounted directly on the rear axle! You might "expect" such a suspension/engine setup to have a lousy ride ... but you'd be wrong!
Design work on the Brow Steam Car continues, with promising results so far. The end of design/blueprinting work and the beginning of build work are fast approaching. After the pump unit is blueprinted, it will be "build time". Since my last entry here, there have been a number of other design and workshop advances, which I hope to detail in future entries.
New Page, Design Progress
Sunday, January 31st, 2010: Now that my old website is permanently archived, with no need to migrate pages or attempt to update old pages, I am starting this webpage to continue the entries on my previous "News" page. Check the old news page for my progress reports of 6-16-2009 and earlier. These give the status of my steam car design to date, and show some of the evolution of the design over time.
As noted in the 6-16-2009 report, the engine, boiler, burner, condenser, water tank, and most other major parts of my steam car powerplant have been designed and blueprinted. Since then, the control system has been simplified and "decentralized". Same basic operation as previously reported, but much simpler equipment.
Control design work led to a recent change in the cold-starting system, mainly with a view to making the car faster and easier to start in freezing weather. Normally, the pilot light is left on, allowing instant starts. But if it is turned off, then when the boiler pressure drops to a low level, about 25 psi, after a day or two, a valve (now blueprinted, ready to build) blows the boiler off to the main water tank. The blowoff steam goes into a separate "bubbler" tube in the bottom of the tank, and is thus condensed -- no cloud of steam out of the car when it blows itself off.
This blowoff valve, by the way, also doubles as a regular blowoff valve for boiler cleaning.
Next time the control lever is pushed to "Start", another valve (Refill Tank Valve) opens, to drain 1.5 gallons of water from a small tank on top of the boiler, down into the boiler, filling it. A fill sensor control automatically starts the main burner when (and only when!) the boiler is full.
When running, by the way, this small Refill Tank is filled up with pump water flowing from the feedwater bypass valve. When tank is full, the feedwater overflows out of this tank into the 10-gallon main water tank.
Now, if the car is left with the pilot off for several days, the boiler blows itself off and the main water tank and the Refill Tank will freeze. To start in this condition, the operator has two options. The easy option is to push the control lever to Start, and let the car sit for about one hour. This causes the pilot burner to light, and it slowly preheats the boiler tubes. Its exhaust is vented into a compact heat jacket surrounding the Refill Tank, slowly thawing the ice in the tank. The water drains into the boiler as it melts, slowly filling the boiler until the fill sensor control (the "Start Automatic") turns on the main burner, and the boiler fires up. Come back an hour after moving the control lever to "Start", and you find the control lever has shifted itself to "On", and the boiler is all fired up and ready to go.
I added a simple option, in case the driver is in a hurry and the car is frozen. Turn the lever to "Start", then open the hood and pour 1.5 gallons of water (room temperature water is OK) into a fill spout on the boiler. A couple one-gallon plastic drinking-water jugs from any convenience or grocery store does the job, or fill a bucket, etc from any available spigot or other water source. Filling the boiler takes about one minute, and the boiler then fires up automatically in about one more minute. Very fast and easy, and with the pilot light, very rarely needed. Probably less time and hassle than many people go through today with their gas cars in freezing weather!
This setup required some redesign of the removeable boiler cap, which as of this writing is now nearly done.
The control system simplification/decentralization which led to this refill tank redesign, took place in October 2009. The Steam Automatic (main burner fuel control valve), using the same spring and diaphragm as a Stanley unit, was designed in July 2009, and the Blowoff Automatic in August 2009. Also in July, the throttle lever, quadrant, and a special remote linkage for the throttle, were designed and blueprinted.
The throttle design included an improvement to the previously-mentioned "drain/vent" valve which releases engine steam pressure for instant stops in close maneuvering. That valve is now directly linked to the throttle lever shaft, and opens without a spring when the throttle lever is moved to "full closed" position. The linkage from this valve to the parking brake was also eliminated. Instead of a key in the dashboard or on the steering column, I decided to go with the much cheaper, easier to design/build, and incidentally more traditional design of a throttle lever which is locked with a padlock! Well, to put on the padlock, you have to pull the throttle lever to "full shut" position, at which position the engine pressure relief valve is wide open. So if the throttle should ever leak -- unlikely with the 440C stainless ball and valve seat -- any slight leakage is vented out of the engine. This avoids the car "wandering" slowly away from its parking place with a leaky throttle, which has happened with some Stanley Steamers!
Angelfire - Free