Relatively Compact Power Generation Using Fuel

[Joseph]

I have some Pittman motors. They do pretty well. They each have a 1/4" diameter output shaft onto which it is not too hard to mount a 1/4" pitch chain sprocket. I got them from Hosfelt Electronics. They are rated for 12V, but I have considered trying to go higher for more power output.

[Joseph]

OS, I think, made a nifty looking rotary engine. I considered it but did not see it for sale. It may be out of production or just too expensive.<p>[ June 03, 2005: Message edited by: Joseph ]</p>

[Bernius1]

It's interesting to consider 'energy density' , and to see the great orders of magnitude between them:
Anti-matter (greatest)
Nuclear
Chemical
Mechanical
Electrical
Gravitational
The greatest chemical densities are represented as the most violently reactive (explosive). Johnson Wax's J-Shop 1200 is 50% Sodium Hydroxide. Mix that with Hydrochloric ( Muriatic ) acid IN SMALL, SAFE, CONTAINED QUANTITES, although any handling & storage are insanely dangerous. What's safer (somewhat) is Hydrogen Peroxide on Silver. The silver acts as a catalyst. One guy a year or so ago made a one-man space rocket, powered by H2O2 & silver, to show it as enviro-friendly. But near-pure Hydroxide will be tough to buy or produce at home, and hazardous to handle. Gasoline is also very dangerous, but thankfully was popularized before the Enviro-Police-Aryans could whip their 'book knowledge devoid of common sense' on it. **C*R*A*S*H** Oops ! of the soap box!

[peter-f]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by no_vice:
... What's safer (somewhat) is Hydrogen Peroxide ...
<hr></blockquote><p>... that brings to mind... it was used as a fuel for a small steam-powered fuel pump on the V-2 (yes, the WWII V-2). I guess they knew about compact power... but it wasn't the pharmacy-style H2O2... it wasn't as dilute... and WAS caustic!<p>The Titan missiles in the USAF (used in the Gemini series of manned flights) used a mix of Hydrazine and (unsymmetrical) di-methyl hydrazine (liquids, both)... but I doubt(!) you can get that without raising a few (hundred) eyebrows!<p>Hey- where's the verdict stand so far... what's still in the running?

[Joseph]

Right now I am contemplating obtaining an RJL (Cox) Conquest .15 engine and then couple it to an electric motor. The problem could be that at over 10,000 RPM, electric motors could have reliability trouble. The rig would seem to need direct coupling, too, since that speed is way too fast for chains, and gears tend to be wasteful from friction. Simplicity, ease of construction, and noise level are also important<p>I need to give more thought to fuel as well. I saw somewhere that it needs to be 20% oil. Interesting thing about it is that I think I saw mention of Castor oil as being an option. Way back when, we used a methanol premix for fuel and we bought it in small cans.<p>[ June 06, 2005: Message edited by: Joseph ]</p>

[jollyrgr]

Hydrogen peroxide may not be a good idea. Remember the Russian submarine Kursk? It exploded because hydrogen peroxide leaked from a rusting torpedo. The hydrogen peroxide then reacted with copper and brass in the torpedo tube causing an explosion. Read about it here:<p>http://en.wikipedia.org/wiki/Russian_su ... #Explosion<p>[ June 07, 2005: Message edited by: Jolly Roger ]</p>

[dacflyer]

joseph >> just what size is this "COX" type model engine? anything in a worthwhile size would be like a weedeatter size engine 25 - 35cu.in.
and any of the smaller ones will be turning so many rpms 15k and above..especially the glow plug type engines..speeds that fast would make a electric motor disintigrate..<p>give us more details on this so that we can understand more, like what size is this motor you have in mind and what engine you will use,and what will you use for a regulator,,also how many watts or amps do you hope to achive? thanx

[Bernius1]

In Mexico they make these things that fit on a bicycle, make power all day, and only require 2 or 3 tacos daily to do this.........

[josmith]

The cox .15 with a generator would make a small power source . I think that the thread about the self powered lights had plans for a brushless generator made from a stepping motor. With a small battery you'll have a hybrid bike.<p>For all the H2O2 dreamers, peroxide isn't a source of energy. It's not even a medium of energy(like hydrogen is) it's a medium of oxygen.

[rshayes]

Hydrogen peroxide decomposes into water and oxygen. In the presence of a catalyst, this decomposition can be very rapid. The reaction releases enough energy to raise the temperature of the water and oxygen to several hundred degrees centigrade. In rockets such as the V-2 and its successors this is used to drive a steam turbine which runs the fuel pumps.<p>This is not an explosion, but if a sufficient amount is released in a closed container such that pressure can build up, the difference may be academic. Many people have been killed by boiler explosions with no explosive involved at all.<p>It is certainly more pleasant than some of the other possibilities, such as hydrazine or nitric acid. These will kill or injure you in vapor form at room temperature.<p>Using an engine to drive a generator to drive a motor does work in diesel locomotives, but it may mot be particularly efficient. Diesel locomotives are efficient in comparison to steam locomotives, but that may not be saying much.<p>Hydrogen peroxide is not readily available. Unless cars start using it, it probably won't be. One of the alcohols might be a possibility. There may be fuel cells that can use it to directly generate electricity.<p>A reciprocating steam engine powered by hydrogen peroxide would be an interesting possibility. It would have good starting torque and clean exhaust. Direct injection of the fuel into the cylinder over a catalyst would avoid the need for a boiler or an ignition system. The lack of readily available fuel would still be a problem.

[Joseph]

dacflyer, the Cox .15 later became made by K&B and now by RJL. The regulation would be done by altering the engine speed. I would like about 250 watts of output power at 12v. Thanks too. <p>Indeed, there is a problem with the speed of the cox .15 rotation in comparison to most electric motors. It is given as 26k rpm while electric motors are rarely rated over 10k rpm. The cox is continuously lubricated. The stepper motor idea with rectifiers would have the advantage of eliminating the brushes, but the bearings could cause trouble. I like the hybrid idea because it does not need to be placed on an external charger.<p>The other problem is the electric motor would need to produce enough torque to turn the engine over without gearing. Higher torque electric motors usually are designed to turn slower.<p>The hydrogen peroxide steam-type engine is appealing in that only one chemical is used, which reduces weight and increases simplicity. Getting the supply of it would be a big problem. That explanation of such an engine is good food for thought.<p>Could hydrazine be the dangerous substance supposedly in the shuttle wreckage? It seems that all remnants of it would be far gone by the time the the pieces reached the ground. I was thinking the danger could have more to do with the heat shield tiles in some way. I think they are some type of ceramic.<p>[ June 08, 2005: Message edited by: Joseph ]</p>

[josmith]

The early space capsules used hydrogen peroxide to supply breathable oxygen.The shuttle may have had some for the same reason. It can cause skin burns and promote rapid corrosion.
I think that NASA overstated the hazard to discourage souvenir hunters.<p>Dreamers just keep on dreaming.<p>[ June 08, 2005: Message edited by: josmith ]</p>

[Joseph]

The idea of discouraging souvenir hunters makes sense. Some people drink hydrogen peroxide but I think doing it is dangerous. I found that the burning action it has even causes sores treated with it to heal slower.<p>I am thinking about only having batteries on the electric bicycle due to lack of an easy option for a compact fuel-powered energy source. I will have to confirm that I want to use lead acid batteries. They are the easiest to charge and the cheapest. But they do not have as much power density as lithium ion.<p>[ June 08, 2005: Message edited by: Joseph ]</p>

[rshayes]

Several web pages indicate that the Space Shuttle uses engines fueled with monomethyl hydrazine and nitrogen tetroxide for orbital manuvering and attitude control. These are both highly toxic. Safe exposure limits seem to be in the tens of parts per million. Those were probably the materials that NASA was warning about as potential hazards in the Space Shuttle debris.<p>I suspect that the corrosive effect of hydrogen peroxide is mainly due to the oxygen released on decomposition.<p>Lead acid batteries might be quite adequate. They are heavy, but until they approach the weight of the bicycle rider, the benefit of the lithium ion batteries may not be overwhelming.<p>A person can put out about 1/6 horsepower for a limited time. This is equivalent to 124 watts. A 20 ampere-hour, 12 volt battery can deliver about 240 watt-hours. This is about one-third the size of an automotive battery. With 50 percent efficiency, this would correspond to about 1 hour of human effort.<p>Try looking up the specifications of electric scooters. This will probably give you a clearer idea.

[Joseph]

Ahh, it is interesting about the shuttle fuel.<p>You had it figured out quite well as far as optimal battery size. I actually have been using a battery about that size on the last version. It had lots of pep and gave a decent range.<p>Since it did not have throttle control the full time I had it, the gearbox became stripped from the power engaging at full force even though I would try to be going several miles per hour before turning it on.<p>I decided to redesign it to make it lighter and less powerful. I had it up to 40 miles per hour on level ground while pedaling as fast as I could on the last version. That is really too fast given the loss of maneuverability from the weight.<p>[ June 09, 2005: Message edited by: Joseph ]</p>