John O'Cain wrote:

This has nothing to do with adhesives but...   I just read two interesting
articles in March issue of Custom Planes. One on the Fadec. Is the same one
that you all have been talking about? The other article was on a Dyna Cam
engine. 200HP / 650 pounds of torque on 80 octane fuel. Haven't seen any
comments in your list or did I just not read em? Some time my light is on
but I'm somewhere else.
John

We discussed the dyna cam engine quite some time OK. IMHO the
main problem is it has too much torque so you need a really big
prop which means a  really long landing gear. Either that or a five
blade and give up prop efficiency. It is a twelve cylinder engine with
a lot of displacement and that is why it has so much torque. It also has
a line contact between the piston roller and cam which limits the RPM
and HP per cubic inch. It is like a monster cam shaft and you know what
kinds of problems you can have a with a cam shaft.

Paul Lamar.

Paul is right.  While there is nothing impossible about the Dynacam,
it has no demonstrable advantages and an unlikely-to-be-reliable
kinematic drive system.  Plus too many cyls/pistons for cost to be
good.  There have been many different kinematic drive systems
used for various prototype engines.  Guess why ALL production
piston engines in the world use a crank and rod system and *not*
a cam & roller or Scotch yoke or Geneva mechanism or a
crossed wingdot & gerflasitz, or whatever.

Sad to say, the rotary is the only kinematically different engine in
about 100 years to have any actual advantages, and even then
it is barely able to compete in the automotive world with the
highly developed piston engines.  The chief advantage of the
rotary is non-existent valvc system and simple kinematic drive
system, both leading to low parts count and mechanical reliablility.
Disadvantages are too much combustion chamber surface area (sub-
optimal surface-to-volme ratio) and special materials needed for
tip seals.  The tip seal has been solved (pretty well) and the
surf/vol ratio is workable with some hits in emissions and BSFC.
A/C don't need to meet emissions stds (yet, yikes) and the BSFC
isn't too bad, esp with a good intake, exh and fuel injection system.
The surf/vol ratio is why these have been developed as stratified
charge motors in many cases - trying to fix this weakness.

Dynacam is not likely to ever do anything notable, other than provide
a focus for an apparently endless string of dreamers or possibly
charlatans (no offense intended, I have no idea if the promotors really
*believe* what they are saying)  to keep it "alive".   Best of luck to
them, it's a free world, they MIGHT succeed, but I wouldn't
bet any of my money on it.

Bill

 
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