Why is it difficult to scale-up the size of a model  LTD Stirling engine?
101281
well with most engines, the larger they are, the greater the frictional losses are.  a LTD (low-temperature-differential) stirling can operate on such a small temperature difference because they are so small and light, and because there is very little losses (air drag around the wheel, and friction in the bearings/moving parts).\n\nin general, the heavier something is, the greater the sliding or rolling friction is.  the frictional force of a mass sliding on a surface is proportional to the mass of the object (actually, proportional to the force with which it presses down on the surface).\n\non the other hand as you increase the size of the stirling engine, you find a case of diminishing returns in terms of the work you can extract.  have a look at the very first diagram on this page:\n\nhttp://www.cse.iitk.ac.in/~amit/courses/371/abhishe/main2.html\n\nthat is a closed curve that represents the stirling cycle.  the work that can be extracted from one cycle is the area inside the box.  notice that the top and bottom parts of the box are curved.  these are isotherms or lines of constant temperature, and those temperatures are the two temperatures in the differential that drives the stirling engine.  notice that as you increase volume, they get closer and closer together.\n\nso think about what happens if you scale up the size of your engine.  the box that defines the stirling cycle grows towards the right, but because those isotherms are getting closer and closer together, the larger you make it the less additional work you get.  at some point you  will stop gaining any measurable amount of work at all!\n\nso there is a trade-off at work here - on the one hand, a larger engine means more work can be extracted - but more frictional losses, too.  \n\nsince the amount of friction grows linearly with the size of the engine, and the amount of extra work grows less-than-linearly with the size of the engine, then the best ones are clearly the small ones!  if the amount of energy extracted grew at the same rate as the amount of energy lost through friction, then all sizes would be equivalent.  \n\nps - this relationship also holds true in 4-stroke otto cycle internal combustion engines, and pretty much any thermodynamic engine - and it's why big engines typically have several cylinders rather than one humongous one.  bigger cylinders gain you less and less.
182772
The larger fan face/surface increases drag and balancing such a large fan becomes difficult, also the power generated by that much more fan disc area would not affect traction or thrust appreciably compared to the weight and complexity of the engine. There were concept jet fans with exposed six bladed propellers driven by more standard jet engines in the late 1970's but conventional turbine power quickly became just as officiant if not more and eclipsed the technology.\n\nKeep in mind, these power plants are designed to operating mounted to or buried within airliners. The master design of the aircraft dictates the size, thrust, weight and length of the engines.
258620
Make Magazine Online gives directions for doing a small batch at home; from there you can scale up.\n  \nhttp://www.makezine.com/03/biodiesel/      more at:\n \nhttp://www.google.com/custom?domains=makezine.com&sitesearch=makezine.com&q=makezine.com+biodiesel&cof=GALT%3A%23008000%3BGL%3A1%3BDIV%3A%23336699%3BVLC%3A663399%3BAH%3Acenter%3BBGC%3AFFFFFF%3BLBGC%3A336699%3BALC%3A0000FF%3BLC%3A0000FF%3BT%3A000000%3BGFNT%3A0000FF%3BGIMP%3A0000FF%3BFORID%3A1%3B&client=pub-1711976718738240&forid=1&ie=ISO-8859-1&oe=ISO-8859-1&hl=en&sa.x=11&sa.y=7
861947
We rebuild cylinder heads from the small aluminum to large diesel, replacing valve guides, seats ... We rebuild cylinder heads from the small aluminum to large diesel, replacing valve guides ... Only place I found it listed was MSN Search besides references to it on Yahoo-answers (CompuServe, Netscape Netcenter, AOL Search). Try using freewebsubmission.com. Usually takes 6-8 weeks for a new site to get listed on Google see your site was modified 10/26/2006 4:33:46 PM so don't get exicited yet about it not being listed, save your money and just use free website submits the pay submits are a waste of money. do a search for my site keywords "Silver Moon Furniture" and see where I place at on Google. My contact information is all visable feel free to e-mail me if you have any questions
97819
Object as in symbols?\n\nIf you have a symbol you could change the coolor of it wthought affecting the size from the tool bar on the bottom.
191596
Sounds like you're talking about a magnetic levitation train or maglev for short. This is not an easy project and you will likely have to fabricate the magnetic track and induction coils (still do some searching, but I don't know of anyone that carries model sized maglev material). I have included a couple of links for you to get started with. Good luck!
35229
Start with a multi-cut-out prototype & tape.  Once you've figured the sizes for your parts, disassemble and use a prototype 1-piece pattern with tabs & slots to hold it together.  Work it till it works  :-)
27169
Use a .940 Stevenson dial-a-phram calibrator on the side-adjust bezel to alleviate possible imbalances in the lower unit p1 thru p12 bindings. ONLY THEN can you use the Hildebrand crollater to adjust the back flow ventilators which do, in fact, allow adjustment of your FP in the p13 and p14 bindings.\n\nP.S. If you are using a 1983 or older "Hilde-Crow", be sure to clean the Skrendeck valves before use.
971735
It sounds like you have looked at the most likely sources. \nI think I would definitely try to raise the brushes as the motor is winding down just to eliminate that possibility (wear insulated gloves).  A pencil eraser held lightly on the commutator will also temporarily quiet the brushes. \nDepending on the frequency other possibilities are a loose field pole piece. This could be loose to the frame or the coil could be loose to the pole piece. The same also goes for the armature coils. At 7.5 hp. coils are prone to move around and get noisy. This is more common after overheating. If the bearings are sealed , check that the seal has some lube on it. \nIf it is equipped with a fan check it for clearance and also check where its collar mounts to the armature shaft for looseness and movement. Red dust here is a telltale sign. Depending on how the armature is fixed to the shaft a loose fit here could also cause the chirping. \nA well placed drop of oil on the most unlikely spot may expose the source. More headbanging, some luck and persistence may be required.\n\nI've been there a few times myself. \nGood Luck
1024952
Try reading the manual. I know its difficult but it could work, or maybe go to where you got it.
4899
You are already stressing the components of the motor by almost doubling the cubic centimeters and in my opinion adding the extra horsepower of nitrous to a motor that wasn't ment for it would cause blown head gaskets, overheating and piston melt down. Those motors are touchy enough without the nitrous!
1036190
If your refering to using a larger drive than needed for the application. Then I would say only limited by your cost and if the drive can be adjusted to the motor/load you are trying to use.
294062
In theory it could work but the process would create a large amount of heat and therefor the engine would be so heavy that it would not be practical. Maybe in a stationary application?
1014182
Designing one is relatively cheap. Building a prototype is not so cheap. You would need to use precision linear stepper motors or other actuators and their power supplies and  cooling systems and so forth.\n\nI suppose that if you already have a lathe or milling machine you could possibly modify it by replacing the manual positioning and stock feed or tool advance controls with the above computer-controlled steppers, etc. I don't think it would do as good a job as a commercial unit. You would have to have a separate controller for each axis or each degree of freedom that the machine can work in. \n\nHave you tried looking for a used cnc machine that someone might be replacing with a newer unit? It is rare that they would just junk them; you might be able to find a used one or a model that is no longer in production. Try contacting manufactureres. Those are my best ideas, Hope they help.
458494
Are you referring to the Sterling Engine? Have you done a Patent search? Go to USPTO.gov\nSolar powered engines have been designed to work with the principle advantage of thermodynamics and or electrical generation. I really would not assume that your concept of solar power is inclusive of one or the other.
261898
I've added some links where you can contact & get some help on that size battery you need.  Good luck!
515576
See at: http://en.wikipedia.org/wiki/Newcomen_steam_engine