Paul, Do you know anyone who could act as a consultant to a company
that is developing a new type of rotary engine? They need help with
seals. Mazda seals won't work. Thanks. jd

No I don't. If they would consult with me I would tell them to forget
it. Rotary engines have been around since the 1500's. Felix Wankel
studied the heck out of them. I have his very comprehensive and
detailed paper on the subject.

Like Kenichi says; a new rotary has a snow balls chance in hell of
working given the billions Mazda has already invested in the Wankel.
What Mazda has achieved is quite remarkable.


Paul Lamar

------------------------------**-------------------- By Kenichi
Yamamoto from his book "Rotary Engine" 1981

1.3 REQUIREMENTS FOR A PRACTICAL ROTARY ENGINE Although various
types of rotary engines have been developed to date, there are few
that do not qualify as internal combustion engines or do not qualify
as a practical engine even if they satisfy the qualifications of an
internal combustion engine. The requirements for a rotary engine to
be qualified as a practical internal combustion engine can be summed
up in the following five items. The practicality of various ideas on
rotary engines can be judged by evaluating them by these criteria:

(1) Every moving part, including the timing mechanism, should make a
rotating motion. A mechanism having a reciprocating inertia will
increase mechanical noise and vibration, and will work against high
speed and high revolution. [In addition mechanisms that reciprocate
generate reversing loads. Reversing loads lead to reversing stresses.
Reversing stresses lead to metal fatigue and limited life. The Wankel
rotary engine has no reversing stresses therefor the life of the
major parts such as the eccentric shaft and rotor are unlimited
unlike, crankshafts, connecting rods, pistons and poppet valves. Paul
Lamar] Accordingly, structures that require intake and exhaust
valves and mechanisms using the rotors oscillatory motion are not
desirable.

(2) Gas seals or the working chamber should be three
dimension-ally reliable. The gas seal mechanism of a rotary engine
should be constituted by connecting the individual seals three
dimension-ally. Among the many ideas we come across are those that
don't show such three dimensional thoughts.

(3) Appropriate gas exchange of intake and exhaust should take
place. Together with having a mechanism that can correctly open and
close the ports, sufficient time for intake and exhaust should be
provided especially for high speed and high revolution. Among the
ideas on rotary engines, there are some that ignore this point.

(4) Every component part should have the strength to endure high
speed and high pressure. As the component parts are exposed to high
pressure, high sliding velocity and high heat load, every part should
have sufficient allowance in size and in shape.

(5) Sufficient cooling and lubrication should be provided. In
order to qualify as an internal combustion engine, although this is
related to above (4), durability against high heat load, high sliding
velocity, etc. are required. Therefore, the structure should be
simple, and the ideas on rotor cooling, lubrication of seal parts,
and oil seal structure should be those that are given adequate
thought. Also, it is desirable for a practical rotary engine to have
a simple and compact structure. When we evaluate the various type's
of rotary engines devised to date in view of the above mentioned
requirements, the NSU Wankel type rotary engine is the engine that
best satisfies the above mentioned requirements.


------------------------------**----------------------------- History
of the invention of the rotary engine by Julian Marsh

1588 Ramelli, an Italian engineer invented a water pump which
continues to be used in oil pumps and compressors.

1636 Pappenheim, a German engineer invented the gear pump which is
still used to lubricate engines. This gear pump made it possible to
dispense with the reciprocating slide valves used by Ramelli. [Fig
3]

Pappenheim drove his machine by an overshot water wheel set in motion
by a stream and was used to feed water fountains. The emperor
Ferdinand II granted him a privilege - the equivalent of a patent in
respect of this invention.

Even in the 17th century, engineers were trying to solve the problem
of leak-proofing between moving parts and this problem continues to
be the Achilles heel of the rotary piston engine although Mazda would
seem to have reduced this problem to manageable proportions.

1650 Otto von Guericke built a vacuum pump which employed leather
washers to prevent leakage between cylinder and piston.

1782 James Watt who invented the steam engine?s connecting rod crank
mechanism which made it possible to convert the piston?s
reciprocating motion into rotary motion designed an oscillating
piston machine in which a wing-shaped rotary blade performed an
almost complete revolution uncovering inlet ports in a chamber
separated off by a curved radial wall. [Fig 4]

1799 One of Watt?s co-workers, Murdock, adapted Pappenheim?s gear
pump to create a rotary piston steam engine. [Fig 5]

1846 Elijah Galloway built the first rotary piston engine with inner
epicycloid and enveloping outer line. [Fig 6]

1859 Jones, modified Pappenheim?s gear pump and produced a double
rotor with only two teeth per gear. Rootes compressors and pumps
employ this principle. [Fig 7]

1900 Alotham and Franchot designed a vane compressor comprising a
bust rotating inside a cycloidal housing. [Fig 8]

1901 The American, Cooley, lodged a patent for a rotary piston engine
with an internal epicycloid and enveloping outer chamber. [Fig 9]

1908 The Englishman, Umpleby, transformed Cooley?s steam engine into
an internal combustion engine but experienced problems with gas
tightness. [Fig 10]

1923 A Swedish patent was granted to Wallinder and Skoog in respect
of a true rotary piston thermal engine with toothed meshing,
enveloping interior hypocycloid and internal five pointed rotor with
a 5:6 rotation ratio which could be used as either a two or four
stroke internal combustion engine. [Fig 11]

1938 Sensaud and Lavaud, (the French engineers responsible for the
Traction Avant automatic gearbox which was a failure) applied for a
patent for a rotary piston engine with internally meshing gears in a
hypocycloid housing and a 5:6 reduction ratio. Both Renault and
Citroën, at the instigation of the French Air Ministry provided
backing for this project and a number of engines were built at
Batignolles. Unfortunately the engine failed to live up to
expectations and the project was abandoned. [Fig 12]

1943 The Swiss manufacturer Bernard Maillard built an air compressor
based on a British patent for a rotary piston machine with a 2:3
ratio and internal hypocycloid surfaced chambers. Leakage under
pressure made it impossible to use this design as a thermal engine.
[Fig 13]

Hi JD,

"Rotary Engines" stand or fall with the sealing system.
The seals make or brake them.

For any advise the parts need to be known and how they interact. Saying its
is a rotary is not enough. Some rotary designs simply cannot be sealed like
Fig. #9 above where rotating and stationary seals would need to be present.

Rolf

The Rotary Engine News Letter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
You Tube http://tinyurl.com/beqqxas
Copyright 1998-2013 All world wide rights reserved.