Here are some clipped figures from a good paper.HuangFigs.pdf (241.08 KB) This shows how the harmonics are really a leaking away of energy from the fundamental f1 wave. Left-side figure is time on horiz axis. Right-side figure is frequency on horiz axis. In this particular paper, they inject frequencies that match the harmonics but 180 degress out of phase, so as to cancel the second and third harmonic. Neal is doing nearly the same thing, except the wave filter branches reflect to cancel the harmonics, also with 180 degree phase cancellation. This is known as destructive interference of waves. The whole goal being to block the energy escape so the fundamental wave can grow to a high level.
Not sure if Renny is the sole person on this forum, if so it would be easier just to use private emails for correspondence. I was under the assumption that the purpose of using public forums was to get involvement from a larger group of interested people. With many hands, the work is easier. Comments and questions is what flushes out ideas. Challenging ideas is what forces proofs and this reveals any underlying weaknesses or strengths in the idea. For the effort of time and money to build hardware, you really need to know what you are doing, or planning to go, ahead of time, in my opinion.
Not sure if Renny is the sole person on this forum
I'm here, tommy. Nothing to add to your fine work right now, but you never know...
And more to the point, I or some other person totally unknown to you might be the one to contribute the missing element that solves your puzzle! You'll never find that out if you keep your thoughts private.
The absence of any generator/alternator on the Model 39, or separate battery to power an electrical system, supports a conclusion that Neal has now done away with the heater shown on his earlier patented model.
One reason why the Model 39 would not need heaters, but the patented V16 requires them, would be if the Model 39 simply uses air at full tank pressure - without any expansion - but the air leaving the storage tank in the V16 *does* undergo expansion before reaching the motor cylinders.
Referring to Fig. 1 of Neal's patent, while the part is not numbered, the drawing appears to show a gate valve with a handwheel on the pipe (82) which leads from the storage tank to the motor cylinders. This gate valve is located before the pipe splits into separate branches leading to the two motor cylinders. If this gate valve is not fully opened, the 200 psi air from the tank will be throttled by the partially opened gate and expanded down to a lower pressure. The air would get much colder during this expansion and explain the heaters.
On the other hand, if the 150 psi air leaving the storage tank in the Model 39 is not expanded, and enters the motor cylinders at full pressure, there would be no need for the heaters.
This raises the question of how safe it is to assume the pressure in the motor cylinders of the patented V16 is actually at 200 psi, when they may instead be driven by a lower pressure. Additionally, if the volume of air is expanded to a lower pressure, and then reheated, this would increase the volume of air available to drive the motor cylinders. As a result, it would also increase the number of revolutions powered by a given volume of 200 psi air extracted from the tank.
Yes, I have more info on the harmonic effects of resonators. Will dig some up to post. That will show more clearly.
Thanks, Tommy! I've been reviewing your posts on harmonics, and I have to say that last one has really grabbed my attention. It may be my new favorite thing! And it definitely already has me hunting for more information.
The helmholtz lining along a pipe will slow down wide areas of higher frequencies, but the straight branched pipe is selective, it narrowly removes only specific frequencies.
I probably should have been more specific. I believe the information I mentioned was based upon the use of standard Helmholtz resonators without any sound absorbing lining within the volume bodies. In that circumstance, it's my understanding that the Helmholtz resonators should also be acting as narrowband filters attuned to a specific frequency. For example, this site states:
A standard Helmholtz resonator will eliminate almost all noise of a very specific frequency and very little around it. By putting sound-absorbing material or angular shapes inside the body, the behavior of the resonator can be changed to eliminate sound over a wider band of frequencies.
Will post more on air resonators. Have huge collection of papers on these.
I've tracked down the full paper from your last post on harmonics and it's really excellent. It does a great job of explaining exactly *how* harmonics are generated to begin with, and how that relates to the best way to prevent them from forming in the first place.
Here is a patent showing a wave filter used similar to Neal's. The math formula can be used with Neal's patent drawing lengths to get a graph of the frequency response, attached. NealFilterGraph.pdf (18.84 KB)NealFilterLengths.pdf (8.95 KB) If you know how to use excel, let me know via message, and I can email you a copy of that excel file. The parameters for the classic wave filter are: branch length, branch spacing which is half to either side of each branch, and the ratio of areas of main pipe versus branch pipe. The graph shows the two lowest frequencies that are removed. There are some higher multiples also being removed. These two being removed are harmonics of the lower freq of 175 Hz, which is not affected at all.
Helmholtz resonators are commonly used for filtering noise or pulsations. In all applications that I have seen, the Helmholtz is used to remove ALL pulsations. It's response is wide, meaning it effects nearby freqs to some extent above and below the center freq it is tuned to. The Helmholtz is commonly used; for example there is one on V8 engines molded into the large plastic duct for air intake to the throttle body. Since the Helmholtz contains a volume, that volume can cause effects to the outside pipe because the outside pipe has only a smaller volume. This means that Helmholtz can change, or warp, the resonation response of the outside main pipe. If a certain application wants to suppress pulsations, then the Helmholtz is the way to go.
Compare to Neal, where Neal only wants to suppress harmonics, but Neal does not want to cause any degradation to the fundamental wave of 175 Hz. The classic wave filter uses narrow side branches that have low volume and their freq response is across only a narrow band of frequencies. Also, the side branches cause a much higher amount of attenuation at the tuned freq, as compared to the Helmholtz.
I think these are the reasons why Neal's design is using quarter-wave branches instead of a Helmholtz resonator.
Some talk about cones in pipes. There are two important things about cones. It took me a few years to figure out the second item, even though it is plainly stated in math formulas of the texts, but is not so easy to see if not explained by somebody first.
1. When a travelling wave, or standing wave, approaches a cone growing ever narrower, the pressure peaks of the wave grow larger and larger as the cone narrows. This tells us that whatever are the pressure peaks of Neal's main pipe resonating wave, at the jet exit of an injector, at that location the wave pressure peaks will be at a substantially higher pressure level. The cone needs to have a shallow angle of convergence to maintain stability of the narrowing wave so it does not breakdown into turbulance, which is called boundary level detachment. This is the long-narrow plumb-bob shape described by Neal's young son's memory.
2. A cone resonates "as-if" it was a pipe with both ends open. This is counter-intuitive, you would think if the cone grows ever narrower, and if the wave in that narrow portion has higher pressure, then that would lead you to think the cone would appear as some sort of closed end. But that is not true. There is complex math behind it, but the ever-narrowing cone shape appears to the outside resonator as if it were a open-open pipe. The approximate length of the open-open pipe seen is the length along the angled cone side, but, with Neal the cone angle is very shallow so that length is very nearly the same as the straight length. When building a model, a sliding pipe adjustment, a trombone slide, can be used at the entrance to the cone so as to adjust for best length.
At room temp, sound speed is 343 meters/second = c. c= frequency * wavelength. So for 175 Hz, 343/175 = 2 meters wavelength. Neal's front end of main pipe is closed end. Rear end is an injector nozzle, seen as open end to the resonating wave. This tells us the main pipe total length will resonate at 1/4 wavelength, and 3/4 wavelength, and 5/4 wavelength, 7/4, 9/4, .... Because it is a closed-open pipe so far as resonation is concerned. 3/4 wavelength of 2 meters (175 Hz) is length of 1.5 meters, 59 inches. Roughly from Neal's figures, say each cylinder is 4 inches diameter and 1.5 inches between each, there are 8 cylinders along block, then block is roughly 46 inches. Now, add a long skinny cone to the rear end with some pipe connections of 13 inches, and the total resonator length becomes 46+13=59 inches! This tells us Neal's main pipe could be designed to resonate at the main pipe's f2 wave which is 175 Hz.
Note there is also a lower freq possible, that is for 1/4 wavelength at 1.5 meters length. 343/ (1.5*4) = 57.17 Hz. From the resonator, main pipe's, point of view, resonator f1=57.17 Hz and the odd harmonics can also resonate, 3x, 5x, 7x. Each of these resonating waves, IF they can grow to a large level reaching saturation, each will produce it's own harmonics of both even and odd. Neal's wave filter dimensions tell us it is designed to remove both even and odd harmonics of the resonator's f2 wave which is 3x 57.17, or = 175 Hz. So....assuming you are following this line of reasoning....the other resonation waves do not have harmonic suppression, therefore they do not grow to large levels and instead saturate at the low 10% pressure increase of a typical straight pipe standing wave. Only the 175 Hz is the "chosen one" to grow large. Make sense? Comments? Any holes in the logic here? The more you dig into the details of this Neal machine, the more of a historical mystery it becomes!
Here are two attachments which discuss the Equalizer. There has been much speculation over the years about Neal's usage of the word Equalizer, and what that meant. If we agree that Neal's machine contains pulsing or resonance, then I am confident this is what the word Equalizer implies. However, any idea or proposition must be able to withstand debate and challenge. EqualizerNotes3-16-21.txt (4.55 KB)NavyGraph1962Excellent.pdf (117.28 KB)
Here is a simplified energy accounting for Neal's machine. Some assumptions are made, do readers think these are accurate? Am hoping a reader will verify the math used here. 4-6-21.txt (4.92 KB)EnergyDiscussion.pdf (162.39 KB)
Interesting idea, tommy. But wasn't there a report of Neal's engine sitting in a workshop, maybe running a lathe, with the pressure relief valve on the tank hissing almost constantly? Pretty sure I remember reading that.
Guess it could still run that way if it had an outside power source, though, right?