Claimed to produce over-unity...
The original idea of the ambient air heat engine was published by
Nikola Tesla in 1900. But Tesla had not worked out what the best
"working fluid" for the system would be.
After years of experimentation, Bob Neal filed for a US Patent in
1934 for an engine/compressor unit that ran continuously from a
tank of compressed air. The engine produced excess mechanical
energy while keeping its own compressed air tank full at all
When the Patent Office informed Bob Neal that his patent claim
would be denied because it was a perpetual motion machine, he
built a miniature working model, put it in a suitcase, and flew to
Washington DC. He plopped the engine down on the patent
commissioner's desk, turned it on, and requested that he be
granted his patent on the basis that the engine worked. His
request was granted in 1936 with the issuing of US Patent
Sometime after the patent issued, Bob Neal was visited by some
German officials who requested that he share his secret with them.
Their request was not granted. Shortly thereafter, Bob Neal's
daughter was kidnapped, and once again the German's requested that
he share his secret with them. As the story goes, Neal took his
working models apart and scattered the pieces around the
countryside. He informed the Nazis that he was through with the
engine forever, and requested that they return his daughter, which
A more probable scenario suggests that Neal traded the secret of
the engine to the Germans to secure his daughter's release, and
then abandon any further work on it for the future safety of his
World War 2 was well underway in Europe, and the Germans were
agressively procurring any advanced technologies they could find.
Toward the end of the war, the Germans perfected their pulsejet
propusion system, which was probably inspired by Bob Neal's
patent, since it uses the same ideas as the mysterious equalizer
that allows low pressure air into his air tank. Of course, the
Germans used their pulsejets to power their V-1 cruise missles to
shower London with bombs.
Bob Neal's breakthrough technology lay dormant for decades until
Scott Robertson dug everything up again and built his astonishing
website detailing the rich history of compressed air technology
and the legacy of the ambient air heat engine demonstrated by Bob
Neal in the 1930's.
Before you lose your perspective on this, a compressed air engine
that runs from a tank that keeps itself at full pressure all of
the time is NOT a perpetual motion machine. It is a HEAT ENGINE
that runs by the extraction of heat from the ambient air, which
was put there by the SUN.
Bob Neal and other compressed air inventors
July 05, 2011
I want to recommend US Patent 2030759 by Bob Neal "Compression
It is a unique way of compressing air using resonance in the
compressor discharge pipe (like water hammer but in air) to do the
compressing in the pipe and in the tank instead of in the
compressor. Water hammer or I should say resonance is the
only method I know of that has been shown to work for getting
over-unity, like the steam generators invented by Joe Griggs and
Carl Schaefer and the air heater invented by Eugene
Frenette. Except other compressed air tricks which I'll
discuss another time. Air is the most natural source of free
energy because it's heated by the sun 24/7.
This has been worked on by a machinist who was in communication
with me for three years. His results were very good but his
machine was not built strongly enough so he moved on to work on a
simpler device of his own. Bob Neal's patent is in the
The Neal compressor has 7 pistons for each engine piston.
The 7 compressor cylinders are evenly spaced around the crank
cycle so the "problem" of vibration in the discharge air is made
"worse" by having so many cylinders. In this case worse is
The engine piston is in phase so that while a standing wave in the
compressor discharge pipe is pulsing air into an equalizer space
in the pipe defined by 2 check valves, simultaneously in the tank
the pulse of air leaving for the engine is communicated to the
equalizer tail pipe which is an open-ended pipe that blasts
squirts of air from the equalizer into the tank. The tail
pipe amplifies pulsations in the tank to produce a strong
rarefaction wave that pulls at the air coming into the tank while
the pressure wave at the intake to the equalizer hammers at the
The compressor has to be as strong as any compressor in order to
compress air to 100 psi normally like any compressor. By
that time it has to reach the right rpm to trigger resonance in
the discharge pipe. When that happens a standing wave is set
up in the pipe between compressor and tank so the compressor stops
running hot and compression takes place in the equalizer instead,
in the middle of the tank. The compressor resists only
atmospheric pressure, it is just an air mover and pulsation
So not only is all compression heat conserved, but the only work
the compressor has to do is to generate a wave of the right
frequency and keep the air moving. Neal's patent calls for
putting air into a 200 psi tank with a single stage compressor
running cool..."impossible" but my machinist friend proved it.
There is much more to say but I'll let it go at that for now.
Pneumatic Options Research Library
September 30, 2013
Nova Neal Compression Engine
Involving a self-sustaining, heat-exchange, air compressor
Compiled by Sterling D. Allan
On September 26, I met with David Yurth, who is the Director of
Science & Technology at Nova Institute of Technology in Salt
Lake City. He and his wife treated my wife and me to lunch, then
took us to their home where David showed me a few videos of some
technologies his group is pursuing, which he'll allow me to talk
The primary reason for the meeting was to discuss open sourcing
the Nova Neal Compression Engine. I shot a video of him giving a
brief introduction, which I've transcribed for the sake of those
of you who visit our site through translation services.
In preface, let me say that while I respect David and his team at
Nova for open sourcing this, and they seem to be a very bright
group, I have a hard time believing this design will work. I don't
see any way that it harnesses the wheelwork of nature, unless it
is a heat pump or something like that, pulling heat from the
http://NovaNealEngine.com - This PESWiki page is the
official page for this open source project.
David's organization website.
In 1936, an inventor by the name of Robert Neal obtained a patent
from the US Patent Office for an engine whose medium of exchange
was compressed air, which was self-sustaining once it got started.
The patent application was initially denied because "perpetual
motion" was a category of application that the patent office had
decided they would not respond to. So, as the story goes, Mr. Neal
packed up his engine, took it to Washington [D.C.], put it on the
desk of the patent commissioner, turned it on, and demonstrated
it, after which, he got his patent.
The story about what happened to the engine is a matter of record.
Eventually, because of interference from people who wanted his
engine and who kidnapped his daughter as a way of compelling him
to relinquish it, he agreed that he would disassemble the engine
and distribute the parts and not make it any more.
In the 75 years since that happened, to the best of our knowledge,
no one has succeeded in either identifying the specific set of
principles that made it work, or recapitulating the engine or in a
newer or similar kind of design.
After about 10 years of research on this process, we know how his
engine worked, and we understand the principles that are involved.
And [with what] we have available today, with 21st century
technologies and materials, [we have the ability] to
operationalize what he created with much cruder materials a long
The engine operates as a heat exchanger. There is nothing exotic
What happens in his engine is this. Two secrets made it possible
for him in his design to build a self-sustaining heat-exchange,
1) He developed a valve that enabled him to put low-pressure air
into a high-pressure tank.
2) He designed his engine in such a way that the first air that
went in was re-compressed to a higher pressure, and the tank he
accumulated the pressure in was designed and put so that he could
retain the heat of recompression.
What that meant was, based on the calculations that we have
developed today, 100 psi air input into his engine at 20
ft3/minute was translated into a much higher pressure that allowed
him to tap the same input volume, but at a self-amplified pressure
that was 8-12 times higher than the original input value.
It's just as simple as that.
So, what we've done is put together an abstract that details the
principles that make it work, a partial list of components that
are needed in order to build one today, and the sources for the
pieces that made his engine unique.
Essentially what happens is that we take a tank of about 100
gallons. The tank is a serious piece of business. You have to make
sure, when you're operating at pressures that are in excess of
1100-1200 psi that you haven't short-cut anything on your tank.
One end of the tank (the dome) has to be detachable, because the
recompression equipment goes inside the tank, and has to be
contained in it, in order for low pressure air to be input into an
internally-held air-booster while the heat of compression is
retained inside the tank.
So, [you can get] a Haskell Boster, or a booster made by Eaton, or
other manufacturers -- ubiquitously available on the Internet,
they use them on the Space Station, you can buy them in a quantity
of one, for anywhere from $2500 to $5000. These are typically the
kinds of devices that are used to take air pressure from a
conventional single- or double-cylinder compressor, and convert
that into 4000 psi pressure in scuba tanks.
We're just going to put one of those inside the [larger] tank;
seal it up; make sure that the tubing and the piping is
pressure-rated, so it isn't collapsed under the internal pressure
of the [larger] tank.
Once that is put together and engineered, then you have a
compressor on the outside of the larger tank, which is driven by
an electric or gasoline-powered engine, and connected by a
slip-clutch of some kind, so that once the engine becomes
operational from the [internal] tank, you can disconnect the
[external] compressor from the extrinsically-powered unit, and
drive it by an air-powered engine, which takes the air off the
[internal] tank, out through the dome.
We've specified an [Angelo] DiPietro Engine, [which we] like
because it has a rotating cylinder, it operates with very high
torque and very high efficiency at a relatively low consumption
rate. So, at something on the order of 18 - 20 ft3 / minute, the
DiPietro Engine, powered by a tank that is compressed at 800 -
1100 psi will enable that little engine to drive two things
1) The first thing it will do is drive the external compressor so
it is continuously recompressing the [internal] tank; but you have
40-45% of the work potential provided by the pressure in the
[inside] tank left over to perform other kinds of work.
2) So the DiPietro Engine can also be attached to a compressor, or
an alternator, or a generator, or a pump, or anything that
requires shaft-driven torque in order to perform work function.
The reason this apparatus works is because the air that is put
into the [inside] tank at 100 psi as the initial value, without
the use of any external, extrinsic, mechanical or electrical power
is driven through the internal re-compressor, which operates by
cams. That's what allows you to put low pressure into a tank
that's re-pressurizing it to about 800 psi. By retaining the heat
of compression, the 800 pounds-per-square-inch pressure coming out
of the re-compressor is further amplified so that you have a
compressed tank at 1100 - 1200 psi at whatever the ambient
temperature is inside the tank.
[By email, David elaborated: It continues to work because air is
constantly being withdrawn and replaced. When the work function
potential is withdrawn the pressure is reduced along with the
volume. When the external air motor drives the compressor, it
regenerates the heat and pressure in a continuous operational
cycle. It is not static – it runs all the time, working to find a
If you paint that tank black, and sit it out in the sunshine,
you'll get an incremental amplification of between 25 and 40% in
addition to the retained thermal value that is retained from the
[Correction: The 100 gallon tank is going to have maximally 2
square meters of collecting sunshine surface. The Sun gives about
1.5 kilowatt per m2. So even if it would collect all of the sun
energy it would increase efficiency by few percent -- not 25-40%.]
So, this engine would cost between $7500 and $10000 to build,
using ubiquitously-available, off-the-shelf materials; and will
generate around 45-48 kilowatts of power, continuous. [That is in
self-looped mode, with no external input to maintain it.]
When you put this thing together, you should have a good heating,
ventilating, and air-conditioning or refrigeration guy help you
make sure that your connections and your tubing, and the other
interstitial pieces of your apparatus are going to be able to
withstand the pressures, so you don't introduce leaks and other
kinds of anomalies into the system.
We're releasing this information. We've done the calculations,
we've tested all the pieces; we're in process of building a
demonstration engine now. We hope to be able to bring that with us
to the next TeslaTech Convention in Albuquerque in 2014.
We're open sourcing this design. The reason I'm doing that is
because I want the design to be in the world. I don't own it. I
didn't create it. I understand it. And I'm willing to share it
with anybody that wants to build it, with absolutely no charge,
and no strings attached.
If you want this information, it's ubiquitously available.
Sterling is going to publish on the PESWiki site. You go there and
download it. If you want to correspond with me about what to do
and how to make it work, I'd be more than happy to entertain your
calls or your inquiries.
There are no fees. There are no charges. There are no strings
attached. If you build it, you own it. And more power to you.
Post by tommy
Jul 5, 2013
Here is what I see with Neal's storage tank. The inlet pipe is
smaller area than the tank and is located one-half the distance of
the tank length. The tank itself is a pipe shape. The tank's f1
has a p node at center. IMO the tank f1 should match the arriving
pulses rate from the equalizer. This creates a for-sure p node at
the tank center, which is also the inlet pipe's open end. The tank
outlet pipe (towards motor) is small area compared to the tank
area and the outlet pipe is at 90 degrees to the tank pipe axis.
The outlet pipe is at the tank's f1 p antinode which is a location
of very low wave velocity, v. The tank's f1 p will only leak out
slightly towards the outlet pipe because the outlet pipe's area is
so very much smaller than the tank's pipe area. Any v coupling
will be small also because the outlet pipe is at 90 degrees to the
f1 v flow inside the tank. If f1 is 175 Hz, then tank inside
length would be about 38 inches, if inside was 48 inches, that
would be about 140 Hz.
If you take Neal's figure 3 and assume the crank pin where the
piston arm connects is a one inch diameter, then you will get a
certain scale. Now if you make the assumption that the lower
figure 6 is drawn to one-half that same scale, then the inside
length of the storage tank is 39 inches, approx. This equals a
wavelength for f1 of exactly 2.0 meters which is what we saw
earlier with the other pipes in his figures. That is an f1 of
about 175 Hz. On Neal's other pages figures, we also saw where the
scales of each drawing was an even multiple of the other figures
scales. This makes sense for a draftsman to do when drawing.
For further study of this sort of tank arrangement, see 2936041
The next step is to work on the pulse timing diagrams from a few
weeks ago, and add more detail with the tank and downstream of the
equalizer. Need to figure out how the main pipe responds to open
vs closed equalizer valves and that will take some drawing time to
figure it out.
Jul 7, 2013
I spent a couple hours with the paper. The most important term
seems to be "transmission loss" which just means sound x goes in
and sound less than x comes out. Peaks on the graph are in
decibels (vertical axis) and at different frequencies (horizontal
axis). Regularity of peaks across the "frequency domain"
(horizontal axis of the graph) indicate harmonics, and the peaks
seem to occur at odd harmonics. So maximum effectiveness of the
muffler is at odd harmonics. That indicates that
quarter-wavelength resonation is occurring inside the muffler.
Which means that sound is being trapped inside the muffler due to
reflection of waves at open ends of pipes.
The basic configuration is a smaller tube going into a bigger
cylinder and another smaller tube coming out the far end of the
big cylinder. The paper deals with different ways in which those
smaller tubes have the effect of quarter-wave resonators. The
idealization of a quarter-wave resonator is a tube with one closed
end and one open end. Waves enter the open end and due to
reflection characteristics, wave energy gets trapped in the tube.
As for Tommy's suggestion that it applies to Neal, I assume he's
drawing a parallel with the pipe entering the tank and dumping air
through the equalizer. The configuration will act like a muffler,
not destroying acoustic energy but capturing it and holding it
hostage so its energy can be directed to a good cause. In this
sense, we might see the equalizer or double check valve as an
energy trap in the end of a pipe; the important part might be the
open end going into a much larger pipe; but I didn't study it
enough yet to say too much. It looks like the author is saying
that the end corrections on the open ends act as quarter wave
resonators in themselves, independent of the tubes they extend
from. If so, then that is new information to me so I might choose
that part to get excited about. New information always tempts me
to get excited; "this could be the missing link," the thing that
made previous understandings incomplete. That's what I'm going to
look at first when I go back to the paper for a second grazing.
End corrections. When waves bounce off an open end and go back
into the tube, they in fact actually bounce off a place slightly
beyond the open end. The difference between where the end of the
pipe is and where the reflection is, is the end correction. The
real wavelength is then different from the theoretical wavelength
which is based on the real tube length. So I thought I read in
this paper that the extended length beyond the end of the pipe
literally functions as a quarter wavelength resonator; an energy
trap where standing waves form. Wavelength of frequencies trapped
can be extrapolated from length of the extension or end correction
beyond the end of the pipe. I'm going to take another look at the
paper, as this is news to me, maybe big news.
Also, while pulsations leaving the tank for the engine represent
acoustic energy, I guess we're saying that the bulk of this
acoustic energy remains in the tank due to reflection at the open
end of the pipe leaving the tank.
That's a very general feeling for how I think the article relates
The invention relates to a compressor construction, and more
particularly to a combination fluid operated engine and
compressor. The primary object of the invention is the provision
of a compressor of this character, wherein there is arranged an
automatically counter balanced crank shaft and...
The invention relates to a compressor construction, and more
particularly to a combination fluid operated engine and
The primary object of the invention is the provision of a
compressor of this character, wherein there is arranged an
automatically counter balanced crank shaft and fluid equalizers
within a storage tank, which makes it possible for the said engine
to operate on constant reserve tank .0 pressure so as to actuate
additional equipment, the pistons for the engine being also
automatically balanced and suspended when the said engine is in
Another object of the invention is the proviS5 sion of an engine
of this character, wherein the same is operated from air under
pressure, the said air being supplied by compressors, these being
in bank with the engine construction.
A further object of the invention is the provision of an engine of
this character, wherein the same is of novel construction, as the
engine proper and the compressors are operated from the same crank
shaft which is of the automatically balanced type, so that high
efficiency is attained. A still further object of the invention is
the provision of an engine of this character, which is
comparatively simple in construction, thoroughly reliable and
efficient in its operation, strong, durable, and inexpensive to
manufacture. With these and other objects in view the invention
consists in the features of construction, combination and
arrangement of parts as will be hereinafter more fully described,
illustrated in the accompanying drawings, which disclose the
preferred embodiment of the invention, and pointed out in the
claim hereunto appended.
In the accompanying drawings:
Figure 1 is a perspective view of the engine constructed in
accordance with the invention.
Figure 2 is a vertical transverse sectional view through
the compressor part of the engine.
Figure 3 is a vertical sectional view through the power
part of the engine.
Figure 4 is a detail elevation of the crank shaft of the
Figure 5 is an enlarged sectional view through one of the
electric heaters for the engine.
Figure 6 is a vertical longitudinal sectional view through
the air storage tank including the equalizer.
Similar reference characters indicate corresponding parts
throughout the several views in the drawings.
Referring to the drawings in detail the engine in its entirety
comprises a cylinder block 10 having formed therein the series of
compressor cylinders II and the power cylinders 12, respectively,
the block 10 being of the V-type and closing the upper ends of
said cylinders are the removable heads 13 and 14, respectively,
which are secured in place by head bolts 15, as is conventional.
Beneath the block 10 is the crank case 16, which at opposite sides
carries the detachable plates 17, these being held in place by
fasteners 18 and such plates are seated so as to be leak proof.
The block 10 is chambered to provide a water jacket 19 about the
cylinders, while at the forward end of the said block are water
pumps 20 circulating water through the inlet pipe 21. which leads
into the jacket and letting said water out therefrom through the
outlet pipe 22 leading from said water jacket. Next to the pumps
20 is a fan 23 operated from a belt 24 which also drives the
Working within the cylinders II are the reciprocating pistons 25,
their rods 26 being slidable through packing glands 27 and fixed
to crossheads 28, which are slidably mounted upon guides 29
secured within the crank case 16 to opposite side walls thereof.
These crossheads 28 are fitted with wrist pins 30 pivotally
connecting therewith the connecting rods 31 which by the bearings
32 are engaged with their cranks 33 of a counter balanced crank
shaft 34, which is mounted in supports 35 arranged in the crank
case IS, the shaft being supplied with the required bearings 36.
The inner ends of the cylinders 11 are fitted with inner end heads
37, which are provided with air intake ports 38, these being
fitted with spring ball inlet checks 39, the air having admission
through passages 40 opening exteriorly of the block 10. The glands
27 are associated with the heads 37.
The heads 13 and 31 are provided with the compressed air outlets
41 and 42, respectively, these being fitted with spring ball
checks 43, the heads 13 being also provided with the central air
inlets 44, which are fitted with spring checks 45.
By couplings 46 are attached to the air outlets 41 and 42 the
outlet feed pipes 47 and 48, respectively, these leading to a main
conduit 49 located in the center channel 50 in said block 10.
At the rear end of the block 10 and on the shaft 34 is the fly
wheel 51, this being of conventional type.
Working within the cylinders 12 are pistons 52, their rods 53
sliding through packing glands 54 and fixed in crossheads 55
slidably mounted upon guides 56 which are secured within the crank
case 18 at opposite side walls thereof. The crossheads 55 carry
wrist pins 57 connecting therewith connecting rods 58, these being
engaged by bearings 59 with their respective cranks 60 of the
crank shaft 34, the inner ends of the cylinders 12 being also
closed by inner heads 61 with which are associated the glands 54.
On the cylinders 12 are slide valve chests 62 in which are the
slide valves 63, these being operated by throw rods 64 actuated by
cams 65 and such valves controlling the air admission and exhaust
of air to and from the cylinders 12 through the ports 66 and 67,
and these valves 63 are provided with the ports 68 for the
delivery of air under pressure from the inlet passages 69 common
to a lead 70 from a compressed air storage tank 71.
The bottom of the crank case 16 is fitted with a removable plate
72 which is secured in place by fasteners 73, and when this plate
is removed access can be had to the crank shaft 34 and the
bearings for the engine, as well as other parts within said crank
case, as should be obvious.
Leading into the cylinders 11 are the passages 14 of a lubricating
system (not shown).
The storage tank i7 for the compressed air includes therein a
double check discharge nozzle 75, this being supported by a member
76 and leading to this equalizer is an air inlet pipe 77 which has
the communication 78 with the chamber 79 formed by said tank. In
the equalizer 75 are the spaced spring ball checks 80 and 81,
respectively, one being for the inlet side and the other for the
exhaust or outlet side of said equalizer. This pipe 77 is
connected with the main conduit 49, while a pipe 82 is connected
with the leads 70, the tank being also fitted with an automatic
relief valve 83 of any approved type.
About the pipes 70 for the passages 69 are the electric heating
units 84 which are for the purpose of heating the air under
pressure above a freezing temperature when delivered from the tank
71'to the cylinders 12.
Supported on the block 10 is an electric generator 85 which is
driven from the shaft 34 through a belt 24 and this generator is
included in an electric circuit which also has the heaters 84 so
that these will operate from current furnished by said generator.
The storage tank 71 with the equalizer is so constructed that it
is possible to pump air into the said tank with a tank pressure of
two hundred pounds, while the compressors are only pumping against
fifteen pounds or atmospheric pressure. Outside air pressure
source can be coupled with the tank to augment that pressure
derived from the cylinders II of the engine.
What is claimed is: In a structure of the kind described, a
V-shaped cylinder block provided with upwardly divergent
cylinders, end heads fitted to said cylinders at opposite ends
thereof, each head having valved inlets and outlets, a main outlet
lead between the cylinders of the block for a storage tank and
having lateral branches to the outlets at the inner sides of said
heads, one inlet being located at the center of each head at the
outer ends of said cylinders while the remaining inlets are at the
outer sides of the heads at the inner ends of said cylinders, a
substantially V-shaped crank case fitted to the block beneath the
cylinders, a counterbalanced crank shaft journaled in the crank
case, pistons operating in the cylinders and having rods extended
into the crank case, crosshead guides fitted to the sides of said
case interiorly thereof, crossheads connecting the rods with the
guides and slidable on the same and connecting rods operated by
the crank shaft and pivoted to the crossheads for reciprocation of