Rotary Engine

The National Exchange ( 1977 )

Revolutionary Rotary Engine to Change Automotive Industry


Tom Valentine

M. Deane Harper of Dunbar WV has invented a rotary engine surpassing anything all the money and engineering breainpower of Detroit could come up with. Good, old-fashioned American ingenuity and inventiveness triumph again !

Harper, a machinist, mechanical engineer and teacher who has a number of inventions to his credit, has developed a rotary engine far superior to the famed Wankel the made Mazda's go hmmm, but also fizzled due to inherent engineering shortcomings.

One doesn't have to be an expert to realize that an efficient rotary engine is far superior to the present day piston engines. However, it remains to be seen whether the Harper rotary has come along too late in the heyday of gasoline-driven motors.

On the other hand, Harper stresses his rotary engine will run well on steam and would be an excellent turbine motor, too.

The Harper design has unlimited potential. The inventor's partner, Robert Weidlich of Charleston WV said:

"The number of desriptive names for this engine is readily outnumbered by the vast potential of use for this new mechanism that changes expanding gas pressure to rotary motion more efficiently than any other design".

Harper has obtained his patent: # 3,809,025.

The inventor and his partner drove from West Virginia to Chicago a few weeks ago just to show this reporter the working prototype. "You can't very well write about something you haven't seen", Weidlich emphasized.

The four cylinder, gasoline-driven rotary spins like a flywheel when it runs. The entire engine rotates.

"It's a rough prototype that we run for only a few minutes at a time because we've not designed any cooling system", Harper explained. "I built it from scrap materials found around my machine shop".

While my knowledge of engines is limited, I do know enough to understand that I was viewing an important moment in engine history as the Harper rotary whirred into action.

The future of the gasoline powered engines may be in doubt, but there's no doubt they'll be around at least a decade or two longer and harper's invention appearsto be the highest state of the art.

The working model was built to prove to doubting patent office officials that the design worked. Then it was transported to Denver where scientists from the University of Denver, Denver Research Instite analyzed it.

Dr Charles Lundin and engineer Frank Lynch signed the report which conlcuded:

"The Harper Rotary Engine is difficult to conceptualize at first exposure, but in truth, is very simple in its operating principles. Since all the surfaces in the engine are circles, spheres or cones, it should not be difficult to produce the parts of the engine with standard machine tools.

"The engine is considerably more compact than standard internal combustion engines and aside from a secondary speed oscillation in the pistons, it is vibration-free.

"The seals in the combustion chamber at any given radius sweep though circular arcs over a constant radius surface through circular arcs over a constant radius surface segments at speeds well within the performance limits of conventional piston rings. If the unusual geometry of the piston causes difficulties in using standard piston ring-type seals, then surely the Wankel-type seals would be more than adequate.

"A cursory mechanical analysis disclosed no unmanageable stress problems. The piston pins in te prototype, however, need to be enlarged.

"One of the most significant features of the engine is its variable compression ratio. By maintaining the highest permissible compression ratio under all operating conditions, average operating efficiencies may be significantly improved"

The report was stiffly scientific, but the researchers managed to make suggestions for minor engineering improvements which indicated their enthusiasm for the device.

"The original concept was slow in taking shape because of the unique surfaces", Harper explained. "The conical surfaces are parallel, perpendicular to and at 90 degrees to the center of the output shaft".

But then, after constructing the model, Harper realized he had one of the simplest engines ever built.

Weidlich listed the possibilities of this Harper design:

"It can be similar to a 2-cycle, or it can run as a 4-cycle gasoline engine; it can operate as a diesel; a Rankin cycle steam engine; a steam turbine or a Sterling engine".

Harper and Weidlich, who are knowledgeable automotive engineers, are certain that their concept of a "positive displacement turbine" will be the greatest imprvement in using steam for motive power since James Watt's engine.

"The positve displacement turbine would have the torque of a steam engine and the low speed of a turbine".

While the technical merits of future production models need to be tested and proved, it is easy to see that as a gasoline-powered engine, the Harper Rotary offers a power-to-weight ratio most appealing to the aircraft industry -- especially helicopters.

If there are any drawbacks to getting this invnetion into production and out into the marketplace to serve our nation, it appears to be in the area of the automotive aftermarket.

Harper's engine will not wear out like today's cumbersome Otto-cycle, piston-driven creatures. Costly repairs and the need for replacement parts will be virtually eliminated.

The consumer can hail this event with enthusiasm -- but not so the national economy.

Since any new invnetion takes time to move from prototype to production, it seems the industrial complex should be able to adjust to the efficiency -- however, a realist will suggest that many jobs and businesses supportive of today's aftermarket will die natural deaths.

To get a partial idea of the impact that could generate if all automobiles suddenly switched to the better engine, consider that Harper's rotary engine has:

-- No parts that stop, start, or change directions...
-- No flywheel...
-- No gears...
-- No distributor...
-- No valves, tappets, valve springs, or push rods...
-- No rocker arms...
-- No counter balances...
-- No crankcase...
-- No connecting rods..
-- No fan...
-- No radiator...
-- Perfect balance, variable compression, self-lubricating seals and seals having a surface speed one-tenth of the problematical Wankel seals.

Harper and Weidlich said they have also contacted machanix Illustrated and other publications, but Exchange was the first to respond. It will be interesting to see how the 'experts" handle it.

This is the beginning of a new era in automotives and this has been a story with a moral.

The moral is: "Our nation would do well to once again rely upon individual initiative, intuition and ability rather than suppress such qualities with arrogance and waiver forms".

Technical Data for Experts --

Displacement -- 38 cu. in.
Bore -- Power segmetn equal to 2-7/8 bore
Stroke -- Angular running plane of power segments equal to a 1-1/2 inch stroke
Firing Chambers -- 4, equal to 4 cyclinders...
Compression -- 6-1/2 to 1 variable...
Intake Vacuum -- 15 inches...
RPM -- Tested at 3200; capable of 20,000...
Physical Size -- 10-1/2 inch diameter; 5-1/4 inches wide, prototype weight 55 lb; could be reduced to 35 lb...
Ignition -- 6 volts...
Balance -- perfect...
Heat -- Air-cooled...
Main Bearings -- Ball bearings...
Power Impulses -- 4 per revolution...
Horsepower -- no rate at this time, but with a 3 hp per cu. in. rating this model would generate 114 hp. If we obtain the same hp as the present day motorcycle engine, we would generate 120 hp...

Murry Deane Harper  
  Robert Weidlich

US Patent # 3,809,025

Abstract -- The rotary engine includes a housing which defines a plurality of chambers for primary compression and combustion and a plurality of pistons mounted to a piston carrier positioned within the housing. Both the housing and the piston carrier rotate at the same rate on separate shafts and the axes of rotation of the two shafts are at an angle to one another. Combustible gas is fed through a central hollow portion of the piston carrier shaft where it is directed into the primary compression chamber by inlet means in the piston carrier which are exposed to the chamber through the movement of the housing relative to the piston carrier. Transport means communicate with each primary compression chamber to transport the combustible gas around the piston from an inlet side to a combustion side of the chamber.

May 7, 1974
Inventors:     Harper; Murry D. (Dunbar, WV)
Assignee:     Harper Development Corporation (Dunbar, WV)
Current U.S. Class:     123/245 ; 123/43R; 418/164; 418/68
Current International Class:     F01C 3/06 (20060101); F01C 3/00 (20060101); F02B 75/02 (20060101); F02b 053/00 ()



My invention relates to rotary engines and, more particularly, to rotary engines in which the axis of rotation of the combustion chamber is at an angle to the axis of rotation of the pistons.

Fluid pumps and motors are known in the art which operate on the principle of rotating chambers and displacement elements wherein the rotational axes are angularly displaced. Attempts have been made heretofore to apply these principles to an internal combustion engine, but these attempts have been directed to apparatus functioning in a known four stroke cycle.


My invention utilizes the principle of the angular displacement of the axes of rotation of chambers and pistons, but these principles are adapted to operate in a manner similar to a two stroke cycle engine. My invention provides a perfectly balanced engine in which pure linear motion is transformed into rotary motion. The engine can be air or liquid cooled. My engine provides variable compression and self-lubricating seals. My engine provides high torque at low speeds and there is no side thrust on the combustion chamber walls as is produced on a standard piston engine by the angle of the connecting rod. The efficiency of the engine and the power curve are such that the size and weight of the engine can be substantially less than existing rotary engines for a given horsepower. During operation, no parts stop, start, wobble or change direction. My engine is an improvement on existing engines from the standpoint of pollution control in two respects. Since the main bearings are sealed ball bearings mounted external of the engine and there is no lateral thrust of the piston on the chamber walls, less oil is required and, therefore, there is less burning of hydrocarbons. In addition, the surface area of the combustion chamber wall to the cubic inch displacement is easily controlled so the engine can be operated at a lower flame temperature than existing engines, thereby reducing the nitric oxide emissions. As a result of the spherical and conical shapes of the engine components, the seal mechanisms are greatly simplified over known rotary engines and line contact seals can be easily employed.

My invention is a rotary engine in which the combustion chambers and the pistons rotate on separate axis with the axes being at an angle to one another. Transport means direct the combustible gases around the pistons in each chamber during the engine cycle so that the operation of the engine is similar to a two stroke cycle engine. The pistons are mounted on a spherical piston carrier which also receives the combustible gas and directs it into the chambers.


FIG. 1 is a section through the rotary engine taken along section line I--I of FIG. 3;

FIG. 1a is an elevation of the engine with the housing removed;

FIG. 2 is a section taken along section lines II--II of FIG. 1;

FIG. 3 is a partial section taken through the rotary engine illustrating the piston member-partition member relationship;

FIG. 4 is an isometric of the piston member;
FIG. 5 is an end view of the piston member;
FIG. 6 is a section taken along section lines VI--VI of FIG. 5;
FIG. 7 is a section through the piston carrier showing the operation of the inlet ports;
FIG. 8 is an end view of the partition member and the seals therefor;
FIG. 9 is an end view of the partition member showing the milled out portion;

FIG. 10 is a section through another embodiment of my rotary engine illustrating different faces of the pistons; and

FIG. 11 is another section through the embodiment illustrated in FIG. 10.

The principles described hereinafter can be applied to pumps, fluid motors and compressors, but are disclosed for the preferred embodiment, a rotary combustion engine.

The engine, generally designated 10, includes a housing 11 and a piston carrier 14, both of which rotate at a common speed, FIGS. 1-3. Housing 11 is annular in shape and has a concave inner surface 17 defined by a segment of a sphere. A top cover plate 12 and a bottom cover plate 13 are bolted to the housing 11 by a plurality of bolts 25 and 26, respectively. Each cover plate 12 and 13 is defined by inner conical walls 27 which terminate in a concave socket 28 which is also a segment of a sphere. Shaft 19 connects to cover plate 13 through a plurality of bolts 20. Shaft 19 represents the power take off for the rotary engine 10.

Piston carrier 14, which is a complete sphere, is positioned within the housing 11 and in operable engagement with concave sockets 28 of the top and bottom cover plates 12 and 13, respectively. Seals 53 in cover plate 12 engage the piston carrier 14. Rigidly secured to the piston carrier 14 is shaft 21 which extends outward through an appropriate opening in the top cover plate 12. Shaft 21 is hollow and includes a central passageway 22 which communicates with chamber 23 located internal of the piston carrier 14. Shaft 21 is positioned with respect to shaft 19 so that the axes of rotation of the two shafts intersect at an angle at the center of the piston carrier 14. This angle, as measured in degrees from a coaxial position and represented by theta in FIG. 1, is variable and will normally be between and

Partition members 16 are positioned within the housing 11 in spaced apart relationship so as to form combustion chambers 35, the inlet side being referred to as primary compression chambers 34, FIGS. 1--3. The rotary engine 10 with four partition members 16 has four combustion chambers 35. Each partition member 16 is substantially trapezoidal in shape and includes a spherical concave inner surface 30 positioned for slidable engagement with the piston carrier 14 and an outer convex spherical surface 29 which cooperates with the inner surface 17 of housing 11. Each partition member is rigidly connected to the housing 11 by four bolts (not shown) which extend through the housing and screw into bolt holes 51 in the partition member 16, FIGS. 3 and 9. The partition member 16 also has upper and lower concave spherical surfaces 48 which engage with the conical surfaces 27 of the cover plates 12 and 13, respectively, FIGS. 8 and 9. Sides 45 of the partition member 16 are convexly shaped so that sides 45 of adjacent partition members 16 define the extreme limits of the combustion chambers 35.

In other words, each combustion chamber 35 and primary compression chamber 34 is defined by piston carrier 14, inner surface 17 of housing 11, conical walls 27 of the top and bottom cover plates 12 and 13, respectively, and convex surfaces 45 of adjacent partition member 16.

Each partition member 16 includes transport grooves 33 which extend along and are recessed in a portion of the surfaces 45 of the partition member 16, FIGS. 1-3. As will be explained hereinafter, the transport grooves 33 serve to transfer the gases from the primary compression chamber 34 around the piston to each combustion chamber 35. Therefore, as long as the grooves 33 perform this function, there can be a single groove or a plurality of grooves and the two grooves 33 on each surface 45 for a total of four grooves per each partition member 16, FIG. 3, or two grooves 33 for each partition member 16, FIG. 2, are exemplary only.

Operating within each combustion chamber 35 is a piston 15, FIGS. 1-6, connected to the piston carrier 14. The piston 15 is also substantially trapezoidal in shape and includes an outer convex spherical surface 31 which slidably engages the spherical inner surface 17 of the housing 11 and an inner concave spherical surface 32 which engages the piston carrier 14, FIGS. 1-3. The side surfaces 46 of the piston 15 are concavely shaped as segments of a sphere so as to slidably cooperate with the convex sides 45 of adjacent partition members 16. The pistons 15 separate the chamber into the combustion chamber 35 and primary compression chamber 34.

Each piston 15 is connected to the piston carrier 14 as follows. The piston 15 includes a rectangular opening 39 extending through the piston and terminating in a cylindrical opening 40 so as to form a shoulder at the juncture thereof, FIGS. 1-6. Piston pin 37 provides the connecting means and is circular in cross section, threaded at one end to threadably engage the piston carrier 14 and has an enlarged head at the other end to shoulder against the rectangular opening 39. A cross sectionally square block 38 includes a cylindrical clear through passageway which accommodates the cylindrical piston pin 37. The block 38 in turn is positioned within the rectangular piston opening 39 in the piston 15. The walls of block 38 are tapered slightly inward from the piston carrier end to the housing end. This tapered axial extent of the block 38 provides increasing clearance in a direction away from the piston carrier 14 and this clearance is necessary for the relative movement of the piston 15 as rotation takes place, with the total relative movement being not unlike a universal in that respect, FIG. 1a. The distance between common points along the center lines of adjacent pistons 15 increases slightly as the adjacent pistons 15 move from a position along the center line of the combustion chamber to a position adjacent opposite ends of the combustion chamber, FIG. 1a. This slight movement of the piston 15 is relative to the piston pin 37 and thus the piston carrier 14 is accommodated by the clearance formed by the tapered walls of block 38.

Exhaust ports 18 extend through the housing 11 and communicate with each combustion chamber 35, FIGS. 1-3. Spark plugs 36 extend through the top cover plate 12 and through the conical wall 27 thereof into communication with the combustion chamber 35.

The fuel mixture such as gas is fed from a carburetor (not shown) into passageway 22 of the shaft 21 and into the chamber 23 internal of the piston carrier 14. Four curved gas inlets 24 extend outward from chamber 23 and an inlet 24 communicates with each of the four primary compression chambers 34, FIGS. 1 and 7. These inlets 24 are opened and closed by the relative movement of the piston carrier 14 with respect to the socket 28 of the bottom cover plate 13. The curvature of the inlets 24 matches the curvature on the socket 28 so that a maximum exposure of the inlet 24 occurs and yet the opening can be immediately closed, FIG. 7.

Each piston 15 is recessed about its periphery by slot 43 which accommodates a piston ring. This piston ring slot 43 is positioned as close to the combustion side face of the piston 15 as possible. Each piston also includes on the combustion side face opposing deflector notches 44 which serve two functions. Namely, the notches 44 place the gases closer to the seal 43 thereby avoiding a wasted length of piston movement. In addition, the shape of each notch directs the gas in a loop scavenging stroke and away from the exhaust ports 18 as will be described hereinafter.

In order to minimize the horsepower requirements on the inlet side of the piston 15, the bottom surface 41 of piston 15 adjacent the inlet port 24 is recessed by cutout 47, FIGS. 5 and 6. Cutout 47 may be recessed in any desired shape to minimize the horsepower required in the compression stroke in the primary compression chamber 34.

The partition members are sealed against the piston carrier 14 and opposite sides of the piston 15 by seals 49 and 50 positioned in mating slots recessed in surface 30 and in the form of a cross. Seal 50 extends into seal 49 so as to provide a lock for seal 49. In order to reduce the weight of the engine, the partition member 16 may be hollowed out such as by conical cutout 52 milled deeply into the interior of partition member 16, FIG. 9.

The operation of my rotary engine 10 is as follows. As the shaft 21 and shaft 19 rotate relative to and at an angle to one another, the piston 15 has the effect of moving back and forth in the combustion chambers 35 even though there is rotation in a single plane. The movement of the piston 15 is between the opposing conical faces 27 of the cover plates 12 and 13, respectively. When the piston 15 is in the combustion position, the gases have been compressed between the piston and the conical surface 27 which accommodates the spark plug 36. The spark plug 36 rotates with the housing 11 and is easily fired through stationary contact surfaces which are engaged by the spark plug 36 as it travels. Combustion creates a thrust on the piston and housing and is directed along the power take off in standard fashion.

At the same time the piston 15 is in the firing position, the inlet ports 24 have been opened and the gases have been drawn into the primary compression chamber 34. As the piston 15 moves away from the site of the combustion, it continues to cover the transport grooves 33 thereby compressing the gases on the inlet side. This compression takes place because the inlet ports 24 are closed and the transport grooves 33 have not as yet been exposed on both sides of the piston 15. This latter circumstance continues until the products of combustion have exhausted through the exhaust port 18, after which the piston 15 exposes the transport grooves 33 on opposing sides of the piston 15 and since the gas is under compression it is caused to transfer to the combustion side, namely combustion chamber 35. This process repeats itself every revolution of the rotary engine 10 so that with the four combustion chambers 35, the engine is firing four times per every revolution. The transfer of gases from one side of the piston to the other is somewhat similar to a two stroke cycle reciprocating internal combustion engine. Of course, with the subject rotary engine, there is no reciprocation of a piston since pure linear motion is transformed to rotary motion.

My rotary engine 10 can be constructed in a number of ways, all of which embody the principles described hereinbefore. A three power impulse per revolution cycle is illustrated in FIGS. 10 and 11. The housing 55 is in the form of a three leaf clover and has an interior surface 56 defining three combustion chambers 60. The housing 55 is constructed in three substantially equivalent segments and then joined by means of bolts 58. Cooling fins 59 are bolted to the exterior of housing 55 by means of bolts 86. A power take off shaft 81 is secured by bolts to the housing 55 and functions in the same manner as shaft 19 of the earlier embodiment.

The housing 55, by being shaped in the form of a cloverleaf, eliminates the partition members of the earlier embodiment. In addition, the housing itself includes the interior concave socket 57 which accommodates the spherical piston carrier 65. Piston carrier 65 is rigidly connected to piston shaft 84 which contains hollow passageway 85 communicating with the inlet ports 68 in the piston carrier 65.

The housing 55 also includes exhaust ports 66 extending therethrough from each combustion chamber 60. In addition, spark plugs 82 are carried by the housing 55 and communicate with each combustion chamber 60. Transfer ports 67 are formed in the housing 55 so as to create a bypass from one side of the piston (primary compression) to the other (combustion) in the same manner as the earlier embodiment. Transfer ports 67 can be milled into the housing 55 or can be separate duct work secured to the housing. These transfer ports 67 perform the same function as the transport grooves of the earlier embodiment.

Pistons 61, 62 and 63 are secured to the piston carrier 65 so that each combustion chamber 60 has a single piston operable therein. Each piston itself has a spherical concave end portion 70 which mates with the spherical piston carrier 65 and a convex end portion 71 which slidably mates with the spherical housing interior surface 56 at the end of each combustion chamber 60. The pistons 61, 62 and 63 differ from the pistons of the earlier embodiment in that each piston includes a flat face 69 on the combustion side of the chamber and a flat face 72 on the inlet side or primary compression chamber. These flat faces 69 and 72 approach corresponding flat faces of the housing interior surface 56 during operation in the combustion and compression portion of the cycle.

The pistons 61, 62 and 63 are connected to the piston carrier 65 in the same manner as the earlier embodiment. Specifically, each piston includes a rectangular cutout 75 into which is inserted a cross sectionally square block 76 tapered along its length and which also has a cylindrical opening clear through. Into the cylindrical opening is inserted the cylindrical section 78 of piston pin 74 so that the piston pin head 79 shoulders against the opening in the piston to hold the piston in place.

An additional sealing and wear feature is illustrated in FIGS. 10 and 11 for the piston pin 74 and the pistons 61, 62 and 63 and such a feature is equally applicable to the earlier embodiment. Piston pin head 79 has a concave undersurface 87 which cooperates with a convex washer 77 positioned against the shoulder formed at the termination of the rectangular opening 75. The washer is hardened steel and acts as a wear plate for the piston pin 74. This arrangement adequately holds the pistons against the piston carrier 65 and prevents the piston through centrifugal force from being forced against the inside surface 56 of the housing 55.

The operation of the rotary engine illustrated in FIGS. 10 and 11 is identical with that of the earlier embodiment except that the engine has three power impulses per revolution instead of four.

The pistons are sealed in the same manner as the earlier embodiment. Each piston includes a seal 80 extending abouts its entire periphery, as illustrated by dotted lines for piston 62 in FIG. 10. More than one seal 80 can be employed in spaced apart relationship about the periphery, albeit only one such seal is illustrated.

Face 72 of piston 63 is inverted, FIG. 10, for purposes of illustrating the plurality of conical cutouts 73 which reduce the weight of the piston and relieves the horsepower requirement of the piston in the compression stroke.

The rotary engine 10 transforms pure linear motion to rotary motion in a totally balanced system so as to obtain optimum performance with a minimum of weight and moving parts.

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