Reaction forces versus expansion forces!

Any comments?

Damn fine question ! ... simple yet thaught provoking.

I too would have plumped for expansion (I do love a good plumping), not really my field so I shall follow with interest.

Del The cat Well!! I would say that it came as a surprise to me too!! I think we are all a little earth bound in our thinking! Anyway, as far as I am concerned, rockets outdo pistons, anytime!!!

Hello D.D.James

This to is out of my league, however an interesting topic, I would agree that expansion would be a more containable, and more powerfull force lb for lb of fuel, but I would believe that there is a cieling to the amount of horse power that a expansion engine can produce, before it's size would render it unpracticle

Hoffj001

They are both caused by expanding gasses.

For the same amount of fuel, the reaction force as you call it, has the advantage for the following reasons.

The weight of the engine (power to weight ratio) is much heavier for an IC engine... more moving and stationary parts.

The effective use of the pressure difference from max to minimum is a much smaller range in the IC engine. In other words, the complete range of pressure is not used, it is inefficient. The rocket uses the complete range, while a jet actually increases the pressure difference by creating a partial vacuum in front, amplifying the pressure, and creating a high pressure behind.

The effective use of the pressure difference from max to minimum is a much smaller range in the IC engine. In other words, the complete range of pressure is not used, it is inefficient. The rocket uses the complete range, while a jet actually increases the pressure difference by creating a partial vacuum in front, amplifying the pressure, and creating a high pressure behind.

I would have to agree with most of this. What got me thinking about exapnsion force versus reaction force, was an article on the super gun, that was built for Iraq by Gerald Bull, a ballistics and armaments expert. The supergun was 510 ft long, weighed a colossal 2100 tons, the breech was 1 metre thick. (I am sorry for mixing up metric and imperial units, but that was the way the facts were presented in the article) and it used almost half a ton of propellant. Inspite of this the maximum calculated distance that it could propel a 500 Kg projectile was a 1000 kms. An ICBM,m weighing a fraction of the weight and using the same amount of propellant could probably put the same load into orbit! Reading this got me thinking about why 'reactive' forces had not been tried in car engines, the reactive force, at least looking at the above example, seems to be "better" by a factor of ten than expansion force. Hence my design of the Rotary Pulse Jet Engine.

On casual observation it appears to me that your engine would not create a great deal of power. A turbine would likely be a more efficient means of extracting more of the available energy from the exhaust gases and converting it to rotary motion. Plus it seems to me that you will have great difficulty compressing the fuel in the combustion chamber in order to get an efficient burn. Perhaps you might find it enlightening to investigate how thermodynamics come into play with regard to heat engine efficiency and how it relates to your mechanism.

Maybe you could just boil water and let the steam jets spin a wheel, didn't the greeks try that? But I think they just used it as entertainment. Maybe because it didn't generate enough power to be useful for anything else.

On casual observation it appears to me that your engine would not create a great deal of power. A turbine would likely be a more efficient means of extracting more of the available energy from the exhaust gases and converting it to rotary motion. Plus it seems to me that you will have great difficulty compressing the fuel in the combustion chamber in order to get an efficient burn. Perhaps you might find it enlightening to investigate how thermodynamics come into play with regard to heat engine efficiency and how it relates to your mechanism.

That is the whole point of the discussion surely, that improbable as it may seem a rocket engine is far more efficient than a piston engine. Secondly a turbine has to burn fuel continuously, so although it may be efficient it is just too fuel intensive to use in a car. What has been done in the RPJ is to take the same (or a slightly larger) volume combustion chamber as in a piston engine, (i.e., the small bit of volume that is left at the top of the cylinder at TDC) and to use a "reaction" force instead of a en expansion force. The air is already pre-compressed! So precompressed air at 125 psi gives a compression ratio of 9 : 1, thus there is no need for pistons, cylinders, crankshaft, cam shaft etc., That is the whole beauty of the design the air is already pre-compressed before it ever enters the combustion chamber, fuel is added and the inlet valve closed, allowing ignition of the mixture in a fully sealed environment. The combusted gases reach pressures of around 500 psi and when released through the CND this pressure is converted into energy.

The temperature rise developed in the "pre-compression" (do you compress it before you compress it?) is wasted outside the heat engine. This will contribute to a lower efficiency of operation and is one of the reasons for the higher efficiency of a diesel or jet engine. Consequently, it is not exactly correct to claim that the engine has a "compression ratio". Nor would the idea of a "compression ratio" apply to a rocket. Rockets are very powerful partly because they utilize an oxidizer that is much more concentrated than 125 psi air and the compression that occurs in the continuous combustion process of a rocket is very high due to the very high rate of combustion. This results in very high temperatures and a consequent large differential in temperature between the high and low temperature reservoirs and a commensurate high efficiency. Due to the lack of compression as part of the combustion cycle and the consequent lack of temperature rise coupled with the relatively low energy content of 125 psi air and injected hydrocarbon fuel I do not believe that you will achieve the efficiency that you anticipate.

Very interesting design. The lower "rocket" is creating a vacuum to help the exhaust of the upper "rocket". The shape and volume of the housing has to be carefully designed in order to make both rockets to "see" the same output pressure. I presume the compressed air and fuel are injected axially. The torque must be an almost rectangular pulse every half a rotation. For this reason, probably 2 or more such "slice" motors have to be phased on a shaft to get a "round" torque instead of kicks.

Did you actually build a working model? My concern is noise and vibration.

Good luck!

Michael

[quote]

The temperature rise developed in the "pre-compression" (do you compress it before you compress it?) is wasted outside the heat engine. This will contribute to a lower efficiency of operation and is one of the reasons for the higher efficiency of a diesel or jet engine. Consequently, it is not exactly correct to claim that the engine has a "compression ratio".

[quote]

I think you will agree that when you have a source of compressed air it is equivalent to a source of potential energy, when you tap that source you change some of that potential energy into kinetic energy. That is why your tyre heats up as you fill it at the service station. Therefore my statement about a compression ratio of 9:1 remains valid.

[quote]

. Rockets are very powerful partly because they utilize an oxidizer that is much more concentrated than 125 psi air and the compression that occurs in the continuous combustion process of a rocket is very high due to the very high rate of combustion

[quote]

We are not talking about a rocket per se but rather about the equivalency between a reaction force and an expansion force under the same circumstances. In other words we don't have to reproduce exactly the same force of a rocket using an oxidizer all we need to do is to produce an equivalent amount of power to an IC piston engine, using the same amount of fuel. The example I had quoted earlier of the 'super gun' seems to bear out my premise that an [1] equivalent amount of power would be produced, as does the working of the Recoilless gun

[quote]

Rockets are very powerful partly because they utilize an oxidizer that is much more concentrated than 125 psi air and the compression that occurs in the continuous combustion process of a rocket is very high due to the very high rate of combustion.

[quote]

I know that rockets achieve high rates of compression (typically 35 – 50 : 1) compression ratios through continuous burning of fuel. One of the reasons that the pulse jet engine was so inefficient is that it could achieve only a 2:1 compression or thereabouts. This is the very reason that the Rotary Pulse Jet would be much more powerful, its final pressure (after combustion) before release works out to almost 35 : 1, not bad eh!

[quote]

The torque must be an almost rectangular pulse every half a rotation. For this reason, probably 2 or more such "slice" motors have to be phased on a shaft to get a "round" torque instead of kicks.

[quote]

Well if you look at the torque produced by an IC piston engine, it is not just rectangular it is extremely complicated, the very fact that the Rotary Pulse Jet Engine yields pure rotary output, should reflect in a significant improvement in efficiency. For instance from the total of 4000 lbsf of pressure available on the piston head in the above example, the final yield in terms of torque is only about 160 ft lbs!

[quote]

Did you actually build a working model? My concern is noise and vibration.

[quote]

I have built a working model on a lathe using industrial nylon, and have tested various crude prototypes but have not as yet found the finance to build a working model. Noise and vibration won't be a problem at all, I believe, but the to test out any hypotheses you have to build a working model!

I think you miss my point with regard to the loss of efficiency regarding the compressed air. It seems to me that much of the heat rise imparted to the air during compression will be dissipated before it reaches your combustion chamber. That energy is consequently lost.

I wonder too if you have fully taken into consideration how much energy is required to compress air and especially to supply the volume your engine might require. Also, to achieve 125 psi in the combustion chamber, and to get that much pressure into the combustion chamber in the short period it would appear that you must will require a reservoir of considerably higher than 125 psi air.

What will you use to compress the air? Probably a reciprocal piston type compressor. Uh.. what does this begin to resemble? To compress the amount of air required to operate an equivalent IC engine would require the same about of displacement as...the IC engine, or a smaller displacement device operated at a much higher speed, like ....wait for it... a turbine. Hmmm, since you will have to have one of these to generate the compressed air, it seems that it might be more efficient to burn the fuel integral to the compression process instead of having the additional weight and complexity (contributing to lower efficiency).

But hey, I'm no expert in thermodynamics and maybe you are. I'm just trying to point to issues that jump out at me as possible logistical problems that you may have not fully considered.

I think you miss my point with regard to the loss of efficiency regarding the compressed air. It seems to me that much of the heat rise imparted to the air during compression will be dissipated before it reaches your combustion chamber. That energy is consequently lost.

I think you might have missed the point regarding why a tyre gets hot while it is being filled with air, that air (normally) comes from a pre-compressed air tank. You might try it out for yourself to see if this is true. Also the compressed air/fuel mixture has to travel a relatively short distance to the combustion chambers, about 4" max, this is done in a fully sealed environment and at pressure, I don't think that there would be much of a chance for the heat to dissipate under these circumstances.

I wonder too if you have fully taken into consideration how much energy is required to compress air and especially to supply the volume your engine might require. Also, to achieve 125 psi in the combustion chamber, and to get that much pressure into the combustion chamber in the short period it would appear that you must will require a reservoir of considerably higher than 125 psi air.

You must have heard of air-brakes surely, trucks fitted with air-brakes usually have tanks of compressed air that are filled on board while the vehicle is running and usually are at about 90 psi to 100 psi, further I think you do not understand the tiny (comparatively ) volume of air about 8 cu ins to 9 cu ins that has to be replaced after each power stroke. (Actually double that since two combustion chambers have to be filled simultaneously) But when you consider that one cubic foot of air is 1728 cu ins. you can see that this is not a problem. The commercially available air compressor I refer to in the site is capable of supply 8 cu ft/minute at 125 psi, its size is 8" x 5", so maybe that gives you some idea. The combustion chambers fill to the correct pressure almost instantaneously, check it out for yourself in any physics book, the air flows into the combustion chamber until it reaches, the pressure of the compressed air being pumped in, this happens almost instantaneously. Or once again go to the service station, a completely empty tyre (R13 size) has a cubic capacity of approx. 3.5 cu ft and it takes just 10 seconds to fill to 30 psi, in fact if you have a good compressor you can fill four tyres simultaneously!

What will you use to compress the air? Probably a reciprocal piston type compressor. Uh.. what does this begin to resemble? To compress the amount of air required to operate an equivalent IC engine would require the same about of displacement as...the IC engine, or a smaller displacement device operated at a much higher speed, like ....wait for it... a turbine. Hmmm, since you will have to have one of these to generate the compressed air, it seems that it might be more efficient to burn the fuel integral to the compression process instead of having the additional weight and complexity (contributing to lower efficiency).

There are many commercially compressors capable of doing at the job, I estimate that maybe 7%-8% of the power output of the engine would be needed to replenish the compressed air that is used, air is relatively easy to compress! As for a turbine I was thinking of something like a pelton wheel type attached to an impeller to cool down the exhauset, that way the hot exhaust gas would be mixed with cool ambient air at a high ratio and then sent to a water cooled radiator to be cooled before leaving the car.

I have not given a lot of thought to this, so I might be off base. If I am, dismiss me as a member of the peanut gallery.

Back a different life ago, a college prof stated that a "typical" IC engine was about 30-35% efficient. Essentially, 30-35% fuel energy as power out the shaft, 30% fuel energy as heat out the radiator, 30% fuel energy out the exhaust pipe, and 5-10% radiated from the engine block. I don't think current percentages are much different.

Turbine engines vary a bit more in efficiency, depending on application. Power plant applications have higher efficiency due to being able to have extra heat recovery equipment on the exhaust, and aircraft applications having less efficiency since they can't afford the weight. 30 years ago, turbine engine efficiency was stated between 25% and 40%, based on application.

You are estimating 8% loss for air compression. Of the 92% left over, what is your extimate of energy loss through the engine casing, and loss through the exhaust gases? What energy is left at the "drive shaft"?

What is the thermodynamic cycle you are basing this process on?

How heavy would you guess a 25 or 30 KW engine would be? An can I bolt a propeller or fan wheel to it?

Well, I've looked at your web site. I have mixed emotions.

Until I see more convincing numbers I will stick with 30-35% energy at the crankshaft coming out of an average IC engine. For automotive use, there are additional energy drops for alternator, radiator fan, drive train losses, tire/wheel windage, air conditioning, etc. that bring an average car's energy efficiency to around 15%. So your 20% number is generous.

What you did not answer is theoretical or estimated efficiency at the output shaft to the rotary jet engine.

After seeing the website, I would guess that maybe 20% energy would be lost through the engine casing, and maybe 40% is lost out the engine exhaust. These are just guesses, but until I see some calculations crunched out by someone, my guess is as good as anyone elses. Adding 8% for air compression, that puts you at abour 32% efficiency.

Since you are in the patent pending process I can understand your reluctance to pass to much data to the world at large. Your do need to be careful with what information you do state, a lot of the comparisons sound liike apples and oranges. I think with a lot of development there could be some merit to your idea, but there is also a lot of missing data for me to want to jump on your band wagon.

Also, your process and cycle has a lot of similarity to turbine engines. That will probably be your main competition and should maybe be thwe focus of you comparisions.

In the meantime, I will go back to the peanut gallery.

What you did not answer is theoretical or estimated efficiency at the output shaft to the rotary jet engine.

Well, ( if you really looked )at the link suggested, your comment does not make much sense !

Your process and cycle has a lot of similarity to turbine engines. That will probably be your main competition and should maybe be the focus of your comparisons.

Not really. A turbine is in reality a captured propeller, a rocket is something entirely different, it provides thrust through the expansion of gases, a turbine pulls in air and uses that air as thrust. As far as car engines are concerned my design wins outright because there is no need for continuous combustion of fuel. You can turn on or off the RPJ at will.

The RPJ has a compressor feeding a combustion chamber. The expansion of the combustion products through a nozzle near the periphery of a wheel creates rotary motion.

The turbine has a compressor feeding a combustion chamber. The expansion of the combustion products through a series of nozzles and blades at the periphery of a wheel causes rotary motion.

The RPJ also bears similarity to Hero's steam wheel. As I recall, no one had efficiency numbers for that device.

The RPJ has a compressor feeding a combustion chamber. The expansion of the combustion products through a nozzle near the periphery of a wheel creates rotary motion. The turbine has a compressor feeding a combustion chamber. The expansion of the combustion products through a series of nozzles and blades at the periphery of a wheel causes rotary motion.

As far as that goes, yes, they are both reaction engines. But in their operation they differ significantly. It is not possible to switch a turbine on and off, further in order to function efficiently it needs to run at very high rpm, typically above 50,000 rpm. The RPJ on the other hand can run at low rpm and function just as efficiently, this is because it is an impulse engine, the force is produced in bursts of energy and not one continuous output.

The RPJ also bears similarity to Hero's steam wheel. As I recall, no one had efficiency numbers for that device.

The same basic design forms the basis of turbines everywhere, namely the expansion and release of gases to provide motivating power.

Hi DDjames:

Cooling down the exhaust gases is a very good thing - and probably a way to recover a good portion of the waste energy. But how are you going to cool the rotor which contains the hottest spots (combustion chambers)? The choice of the right materials is also a food for thinking.

I agree that your concept generates "pure" rotational energy but as you named it, it yields pulsed torque which I'm not very sure will be welcomed by the car industry.

The noise and vibration I was talking about is coming from two directions. First is the nozzle one due to which real rockets are sometimes killing the payload if it wasn't carefully tested before launch. The second is the exhaust confinement that will generate a whole spectrum of sound waves and possibly standing waves.

Please don't take any of my comments as negative. I just try to help you for the real test: to sell your invention. I know how it is...

Regards,

Michael

Cooling down the exhaust gases is a very good thing - and probably a way to recover a good portion of the waste energy. But how are you going to cool the rotor which contains the hottest spots (combustion chambers)? The choice of the right materials is also a food for thinking.

Right now, I have at this moment in my yard a 16 hp Enfield Bullet diesel motorcycle that has been left there by one of my friends while he is out of station, it is air cooled and doesn't give any problems at all no matter for how long you run it. Now consider that the pistons in this engine are aluminium and the temperature at ignition is 3000 degrees centigrade ! as opposed to the 2000 degrees centigrade in the RPJ . Think about how long the temperature is retained in a diesel engine, at least for one fiftieth of a second at 3000 rpm, in the RPJ the temperature is retained for only four or five hundredths of a second, add to this the fact that the whole engine is rotating and that fins can be attached both to draw in air and circulate it around the engine as well as to conduct heat away from the combustion chambers and I don't see cooling of the engine as a major problem.

The noise and vibration I was talking about is coming from two directions. First is the nozzle one due to which real rockets are sometimes killing the payload if it wasn't carefully tested before launch. The second is the exhaust confinement that will generate a whole spectrum of sound waves and possibly standing waves

It might very well be a problem but if the power is there, if the engine runs coolly, if the exhaust does not pose an immediate life threatening situation, if the engine is economical and pollution free. Then, we can always find a way around the sound. As to vibration, I think the vibration will be less than that of a piston engine.

Please don't take any of my comments as negative. I just try to help you for the real test: to sell your invention. I know how it is...

Every bit of criticism positive or negative surely helps in building up a better picture of what to expect. Thanks. DD James

BTW, I have heard of tethered ram jets, which is a similar sort of concept.. An old guy who I worked with years ago (a bit of a mentor) told me how he made one once from an old motorbike silencer....apparently it went like a bat out of hell!

Sound like (rather dangerous) fun...

Hi again..

The more I think about this the more it interests me...

Presumably it will need to spin at fairly high rmp to keep going and will be better for power than torque? A small flywheel should smooth things out nicely and provide a handy way to spin it up.

I'd have though it would be relatively easy to build a couple of ramjets onto a car flywheel for a test bed? (hefty safety cage to catch the bits if it runs away with itself?...ah...yes how do you control the speed.....)

Blimey I'm hooked...where do I sign up?

Del

I'm caught too...

Another thing that crossed my mind is to insure a perfect synchronization of the explosions with the angular position of the rotor. Any misalignment of the nozzles on the rotor with the openings in the stator will cause trouble. Speed cannot be controlled directly but only through torque (for a given shaft load) and that through the air+fuel mix.

I'd have though it would be relatively easy to build a couple of ramjets onto a car flywheel for a test bed? (hefty safety cage to catch the bits if it runs away with itself?...ah...yes how do you control the speed.....)

Ha! Haaaaaa! All I am concerned with is equivalency, if the Rotary Pulse Jet can produce, using the same amount of fuel , the same power output as an IC piston engine ( and I think there is some possibility of this being true, when you consider my example of the super gun) then the RPJ is home free, because it yields an absolutely pure rotary output and not an eccentric one as the Wankel does.

Another thing that crossed my mind is to insure a perfect synchronization of the explosions with the angular position of the rotor. Any misalignment of the nozzles on the rotor with the openings in the stator will cause trouble. Speed cannot be controlled directly but only through torque (for a given shaft load) and that through the air+fuel mix.

Hey, Hey! Are we forgetting that we are dealing with a perfect circle here and it is very easy to synchronise events since there are no complicated linear to rotary calculations to take into account.

I'm not sure that you do need to synchronise anything???

If you take the two ramjets bolted to a flywheel analogy....ignition can take place at any point... fuel can be fed through pipework attached to the flywheel...air is scooped up as it whizzes around and the exhaust sprays out in an allarming fashion!!

Hmmm... maybe you don't need me onboard?

Hey look familiar???? from the Germain V2 Bombers.....

http://conceptengine.tripod.com/conceptengine/id2.html

or this from 1952

http://www.archive.org/details/us_patent_2599209

Hey look familiar???? from the Germain V2 Bombers.....

Hey ! That's my web-site that some gook (geek) screwed me up and I had to start a new web-site! In this version of the RPJ (made seven years ago) I suggested using pistons to compress the air/fuel. My Mistake, the engine became huge and impractical, but Hey ! I am still around, this time with a Rotary Union to help me out Eh! N.B. If any of those links nearly resemble mine they are definitely in patent infringement , right !

Beside (forgive me) Arthur Trice is a git! His engine does not work. The True Rotary Internal Combustion Engine does not work, and I have proved it!

The point is the pulse jet engine was first patented in 1907 by the Frenchman Victor de Karavodine. This in turn had been proposed in 1919 as the power plant for a pilotless aircraft by another Frenchman, René Lorin. And was used in WWII by the Germans to power the V-1 and V-II Buzz bombs to attack England.

The Pulse jet engine has been in Ontario's regular curriculum at least far back as the sixties. Your picture (without the moving graphics) looks exactly like a drawing I made in school in the sixties.

The point is the pulse jet engine was first patented in 1907 by the Frenchman Victor de Karavodine.

This doesn't matter a jot...

A patent can be broadly similar or use bits of prior art... I must however add some unique 'claims'.

Following your assertion, it would be impossible to patent anything pertaining to a 'conventional' internal combustion engine as it was doubtless first patented ages ago.

It is quite reasonable to even take two common items and juxtapose them in a new way to perform some new task and patent this. The bandsaw sandwich.. probably patentable..but I don't think there is much of a market..

The unique claim?

hmmm 'it will cut through your apetite?'

I must apologise once more, for referring to Arthur Trice as a (git) let me assure you that this was in no way meant as a sign of disparagement but more as a token of affection. Anyone who has read of Arthur Trice will know that I speak the truth. Arthur Trice was a successful farmer in England who had spent a lot of money on making a prototype and patenting his Trice Engine, the rights to the patent are now for sale. The same is true of the Idol Motor, its inventor a young Turkish Engineering student, went a step further and took out a dozen related patents on his Idol Motor Engine, the patents are now on sale. The Canadian Inventors of the Quasitrubine engine, which was at one time the hope of the Engineering world has fallen by the way side. The same is true of the ball piston engine ( an American invention) the OX8 and a dozen more. As a fellow inventor, I have been in touch with most of these people at one time or another and have, from time to time, tried to keep track of all of them. I regret to say that most have fallen along the way, but even more surprising is the story of the successes that some of these inventions have achieved. The MIDI air car, which is a car that runs on compressed air has been taken up by Governments ( Yes I kid you not) and large automobile manufacturing companies. Yet it is an obvious scam, even wikipedia calls the compressed air car a scam. Then again an investor (Adams Capital Management and Northern Capital) who was looking for a new form of engine to invest in invested a million dollars in the liquid piston engine, which even a cursory glance should show, will never work because of the problems in sealing. One would have thought that after all the millions and millions of dollars spent on the Wankel engine, the lesson would have been learnt by now.

Your second reference is also way. way off target, although the reference to a pulse detaonation engine is close!

So what is your patent number and where is it patented?

I think this is the old one..

http://www.wipo.int/pctdb/en/wo.jsp?wo=2002063150&IA=WO2002063150&DISPLAY=STATUS

Yeah, well I'm going to have to say that I think this is a waste of time. Clearly this is one of those ideas that has been around for long enough that if it really were a good idea I would have one in my car. The graphic presented, while visually entertaining, does not strike the "wow that's a good idea" center in my brain. It actually seems to activate my "Why in the heck would you want to do something as cumbersome as that?" center.

The author has not presented any clear data on a thermodynamic analysis or actual testing results and there seems to be nothing more substantive than "I believe this works well." which has no more of a basis than my belief that "I don't believe this would work as well as you think." And in my years of design experience I have developed a reasonable sense of what is a bad idea and what is a good idea. And sometimes even if it might be a good idea it isn't enough of a good ideas to make it worth messing with. Those have usually been the customers that want me to invest my time and development costs for a share in the profits. Unfortunately, like the profits from a book that is published with a vanity publisher, they tend to be in the minus column.

I know I'll get flack for being the nay sayer but not all ideas are good ideas, like the band saw sandwich. Just because it could be done doesn't mean you should. There is a difference between something that is just unique and something that is unique and has utility. I think this is just beating a dead horse.

Yeah, well I'm going to have to say that I think this is a waste of time. Clearly this is one of those ideas that has been around for long enough that if it really were a good idea I would have one in my car

With those attitudes I sometimes wonder if you can find the enthusiasm to eat your breakfast...heck you did it yesterday...!

It's easy really, I'm not emotional attached to it. I had to cut back on that behavior because otherwise I would have not only not eaten my breakfast, I would have simply killed myself.

But we have to judge, it's a survival skill. You make innumerable decisions on a daily basis of how to spend your time, what to pay attention to and what to invest your energy in. Do you get depressed when you decide something is a bad idea? That would be sad. Bad ideas are all around us. So are mistakes. If I make a mistake by assessing this to be a bad idea, that also has no emotional impact on me. I discovered a long time ago that I will make mistakes, and so I eat my breakfast and go hmm, how about that.

Would you prefer for me to spout unbridled enthusiasm for something I don't believe in? I don't expect anyone to do that. Seems like the whole idea here is to have a variety of thoughts and opinions.

Because I disagree sometimes is not indicative of an absolute state, emotional or otherwise.

Nah.. just joshing, for the most part.

We all have our own style else it would be a pretty dull forum like you say.

Yes that's a good idea..

I agree a good idea.

Me too, very good...

Cheers

Del

I think it may have been mentioned before, but I don't see why one would want to convert the momentum of the jet/rocket/ion stream/w.h.y into mechanical energy and then lose some of it in some convoluted automotive-style drive train before applying it to the road surface, when you can point the stream straight out of the back of the vehicle with no losses to achieve the same. Inelegant solution to not melting vehicles belonging to other road users if you ask me (no, i know no one did or would be the slightest interested, especially at this point in the life of a thread!).

An interesting thought. What your idea does for me is makes me think that there is a problem matching the velocity of the output gas to the load. In an IC engine the pistons slow down the expansion of gases to a better match for the speed at which they are to be used. It seems, just intuitively, that you would need a lot of little poofs from the size of cylinder suggested or lots of poofs from lots of little cylinders to amount to enough force to be useful. Consequently, with the speed that the poofs would be coming out of the little combustion chambers it doesn't seem to me that it would matter much if they were pointed out the back end or turned a wheel inside a chamber there would still be a mis-match. Though it might be slightly better with spinning the wheel since you could then use gears to match the torque but in my mind you would only be making a bad idea slightly more workable by doing so. Still a bad idea.

An interesting thought. What your idea does for me is makes me think that there is a problem matching the velocity of the output gas to the load. In an IC engine the pistons slow down the expansion of gases to a better match for the speed at which they are to be used.

Here's why I think you are wrong about that, matching the exhaust velocity of the gases to anything is irrelevant, at least in this context, to the power available. Just after the Second World War, an air-craft manufacturing and tyre testing facility was set up in the UK. The tyres were to be tested to breaking point. It was estimated that the tyres would fail at 500 psi. Compressed air was used in the first test, the tyres which had a volume of about 5 cu ft. were filled with compressed air, at 800 psi the tyre exploded taking most of the test facility with it ! They still test tyres to breaking point but instead of air they now use water, which is incompressible. Again in the this forum I quote from: at this thread "And what is really scary that a full (3000psi), aluminum 80 cubic foot scuba cylinder in a catostrophic failure will release 1.5 million foot pounds of energy." So what makes you think the rocket pods in the RPJ will be incapable of delivering power ? Granted the pressure in the pods is only 500 psi and not 800 psi in the example with the tyre or 4000 psi as in the example with the scuba tank, but to my mind that still leaves a lot of usable power! Or do you disagree with this conclusion and if so why ?

"matching the exhaust velocity of the gases to anything is irrelevant"

Apparently modern jet technology is in disagreement with your statement:

http://en.wikipedia.org/wiki/Turboprop

http://en.wikipedia.org/wiki/Turbofan

Turbojets are no longer used on new production aircraft. In particular note in the description of the turboprop that it is the most efficient mode for lower speed aircraft.

If you think about what happens when the gas escapes your short nozzle it seems to me that the turbulence at the nozzle to air interface will cause a considerable off axis distribution of the exiting gases. All vectors off axis constitute a loss of efficiency. When you contain the expanding gas and allow it to press against a fairly large surface all of the expanding gas will be converted to motion in only one direction.

You might also want to look at this on specific fuel consumption:

http://en.wikipedia.org/wiki/Specific_fuel_consumption

Which in and of itself would seem to negate your conjecture that a reactive force is better. The ramjet is pure reactive force and it has a far lower efficiency (higher SFC) than the gasoline ICE. The turbojet, if indicated, would be showing a higher SFC than the turboprop and I'm not sure where in relation to the ramjet.

This also does not consider that the spinning pistons of your impulse jet will also incur frictional losses from spinning in a chamber that is probably at slightly higher than atmospheric pressure. But before we even get there it would appear that the data on SFC alone shoots down the idea of any possible efficiency advantage.

On another point, the difference between reactive and expansive forces seems to not be. All forces (in terms of thrust) are reactive forces resulting from expansion. But it seems that my contention that the manner in which they are coupled to the load is relevant. is incontrovertible, and that the mode you are calling "reaction" is a less efficient mode of coupling than "expansion", hence also collaborating my contention that if it worked better I would already be driving one.

This also does not consider that the spinning pistons of your impulse jet will also incur frictional losses from spinning in a chamber that is probably at slightly higher than atmospheric pressure. But before we even get there it would appear that the data on SFC alone shoots down the idea of any possible efficiency advantage.

There are no pistons. The patent was for an older design which has now been improved and a patent applied for as a completely different invention!

On another point, the difference between reactive and expansive forces seems to not be. All forces (in terms of thrust) are reactive forces resulting from expansion. But it seems that my contention that the manner in which they are coupled to the load is relevant. is incontrovertible, and that the mode you are calling "reaction" is a less efficient mode of coupling than "expansion", hence also collaborating my contention that if it worked better I would already be driving one.

How could you be driving one if it hasn't been built yet ? P.S. What about the exploding scuba tank or the air-craft tyre that burst at 800 psi and demolished the building it was being tested in?

Did you read any of the references I cited? It doesn't matter what the exact configuration is or how much damage releasing a huge amount of potential energy all at once can do.

I think I'm done.

Is this engine to be painted pink?

I don't know. I'm a big fan of black myself but if you prefer pink... It does show the dirt.

I think it may have been mentioned before, but I don't see why one would want to convert the momentum of the jet/rocket/ion stream/w.h.y into mechanical energy and then lose some of it in some convoluted automotive-style drive train before applying it to the road surface, when you can point the stream straight out of the back of the vehicle with no losses to achieve the same. Inelegant solution to not melting vehicles belonging to other road users if you ask me (no, i know no one did or would be the slightest interested, especially at this point in the life of a thread!).

Well it all comes down to fuel economy and in fact to just being able to harness rocket power in a way that you can use (safely) in a car. The point is that using this method it is possible to utilize rocket power in a way that is similar to the way the IC piston engine harnesses power, that is each power stroke is an increment which adds up giving enough power to motivate the power train. A single stroke of an IC piston engine does not in fact generate much power it is the cumulative effect of a whole series of power strokes that provides the power. What the RPJ provides is analogous to this.

So whats the advantage in doing this, to put it in one word a pure rotary output. That is something which a lot of people have been trying to achieve, for obvious reasons, and this is one design that makes pure rotary output a definite possibility.

I think it may have been mentioned before, but I don't see why one would want to convert the momentum of the jet/rocket/ion stream/w.h.y into mechanical energy and then lose some of it in some convoluted automotive-style drive train before applying it to the road surface, when you can point the stream straight out of the back of the vehicle with no losses to achieve the same. Inelegant solution to not melting vehicles belonging to other road users if you ask me (no, i know no one did or would be the slightest interested, especially at this point in the life of a thread!).

I have been giving some thought to your post, and I couldn't help thinking something was wrong, trying to imagine those two tiny rocket pods pushing along an SUV for instance!! But look at it as a purely physics problem. First the air is compressed (i.e to 125 psi) then fuel is added to it and it is ignited in a sealed environment, bringing the pressure up to 500 psi, since the combustion chamber (rocket pod ) is shaped like a cylinder the only place for the pressure to act is on the back plate, if you have a back plate 3" in diameter then the total pressure acting on it would be 3532 lbs of pressure. This pressure of 3523 lbs that is present in the combustion chamber is in the form of potential energy, so when the pressure is released it converts into kinetic energy providing the power. For this not to happen, there would have to be something seriously wrong! Further it brings us back to the start of the thread namely would a reactive force in the given circumstance be as powerful as an expansion force. (i.e. the force acting on the piston. )

Dear Sir, I react very late to an extremely interesting question.

I think that you should first define what is a "reaction force" and then compare with an "expansion force".

I think that the problem is in fact put in the wrong way it is not the force which counts but the "work", the energy (mechanical) either the one solution or the other can generate.

I do not want to argue since I was several times consulting inventors and it is very difficult or even impossible to convince that there is a "problem" somewhere. What i want is only to limit your efforts ans spending which I doubt will lead to an economical result especially in the actual environmental situation.

Hi! Nick I think you can see the answer to this here

At least I think it does answer many of the questions in your post I hope

I am sorry but it is not the answer Please put down your definition and we can discuss

That is his definition. Force is force is the basis of his conjecture and that's all he's got. It doesn't matter to him how you apply it. It is equally effective in any configuration. Equal force = it works equally as well or better. You are wasting your time because he "knows" better than all of us. But knock yourself out, I find it immensely entertaining.

Thanks for your comment. As you noticed I am sorry for him since he will spend energy and money for nothing.

My intention was NOT to try to convince him since I have as a consultant experience with "inventors" who know every think better even if physics are not respected. I met at least 10 perpetuum mobile inventors and only one was able to understand where he made the error but he was not a technician.

If PDJ would make the effort to understand what is a reaction force and how it has to be generated he would understand where he makes the error.

Do not misunderstand me I am not conservative, I think that risks have to be taken BUT on a solid ground at the starting point. I made myself dveloppments which were considered as impossible but I respected the general laws of physics.

Any way it was my 1st and last attempt to open his eyes. I doubt he will ever answer my question.