Well because they use the otto cycle I guess.. intake
compression power exhaust...
Dave
Ed Van Scoy wrote:
>
> Dave;
> What is wrong with just putting rotary engines in their own class, instead of
> trying to get them to fit in an established class (otto) that may or may not
>be
> equal? You could just add an "R" to the engine classes (like was done with
> Turbines) No need to worry how to accurately measure an apple against a pear
> (rotary Vs piston) It wouldn't even matter how the rotary displacement (swept
> volumn) was calculated as long as that same measurement technique was applied
>to
> ALL rotary engines.
> Ed
>
> Dave Dahlgren wrote:
>
> > Gary thanks for replying.
> > The two strokes I agree on completely no question on that.
> > Displacement X 2 as they process twice as much air and fuel
> > as a 4 stroke engine of equal displacement in 2 revs. I had
> > brought this up with Dan Warner a long while ago on this
> > group. But I fail to understand your logic on the rotary.
> > >From what i can see your logic is not based on facts at all.
> > It is based on what it looks like rather than how it works.
> > The engine sizes have been historically based on 4 cycle
> > piston engines. That infers that it is the amount of air and
> > fuel that can be processed in 2 revs as this is typical. had
> > you picked the amount of air and fuel that can be processed
> > in 1 rev then you would have had cylinders left over over.
> > had you picked 3 revs you would have been short cylinders.
> > Is an engine that processes 175 cu in of air and fuel in 1
> > rev with 4 cylinders not done yet, the same as a 350 cu in
> > engine in 2 revs and a 525 that processes all the air and
> > fuel in 3 revs? I suspect they are as they are all 350 cu in
> > engines using the standard displacement per 2 revs.. It is
> > just a matter of how you measure them and the only fair
> > yardstick is how much air and fuel in a given # of revs.
> > Just like it is miles per hour and feet per minute and
> > gallons per hour so is displacement per # of revs. Otherwise
> > there is no comparison at all. If you get a fuel pump do you
> > as for a 100 gallon pump or do you ask for a 100 gallon PER
> > HOUR pump???? Is your car is going 150 miles or is it going
> > 150 miles per hour.... The relationship of displacement per
> > 2 revs has always been inferred and not written out. I am
> > asking for finish writing it out. No more and no less. It
> > all seems very logical to me and ought to to everyone else.
> > I think you have to compare things that are dynamic in a
> > dynamic situation not a static one. What something seems
> > like while stationary has little to do with how it behaves
> > dynamically.
> >
> > In other words.....
> > What you are saying is, if I understand correctly, the
> > rotary is like a 6 cylinder because it has 6 faces total
> > from the 3 rotors. But in only has 2 firings per rev. That
> > means it takes 3 revs to fire them all. Well I have a 4
> > cylinder engine that has 500 cc per cylinder. In 3 revs it
> > fires 6 cylinders... 500 x 6=3000 cc. can I run against the
> > F class records too then? If you do not compare engines by
> > the amount of air and fuel that is processed per revolution
> > then how do you compare them fairly? The simple thing about
> > using that type of comparison is that it is all encompassing
> > and no new rules have to made no matter what type of engine
> > is run. It is the reason that SCCA and FIA use factors of X
> > 2.1 and X 2.2 because that is a fair way to compare
> > engines. It also matches by the way the relative amount of
> > power from this type engine also. If I had a 1300 cc piston
> > engine and a 1300 cc rotary I would expect the the rotary to
> > make about twice as much power as the piston engine. A good
> > 1300 cc piston engine makes about 220 hp. ask any of the
> > bike guys i bet i am pretty close here. if anything a little
> > conservative. A 1300 cc rotary makes about 360 hp. I have
> > dyno sheets of some of the better ones on hand here. using
> > those #'s it puts the rotary at a disadvantage at X2. If the
> > rotary was truly twice as good it would make 440 hp. with
> > your factor it would be expected to make 660 hp. Does this
> > seem realistic? I suspect not! That is because the engine
> > only has 2 firings per rev and the only place and time that
> > any power came be generated is when there is a firing. The
> > rest is a lot of monkey motion with parts going around and
> > around but no power being generated. I hope to hear back
> > from you on these comparisons.
> > Dave Dahlgren
> >
> > Gary Allen wrote:
> > >
> > > I diagree with your logic. I consider a 2 rotor, 3 lobe rotary engine the
> > > equivilent to a 6 cylinder engine with 654 cc in each cylinder for the
>total
> > > displacement of 3924 cc. This is the total swept volume (key term) of the
> > > engine just like piston engines are measured. If your recommended logic
>is
> > > accepted, then I would expect the 2 stroke engines to be measured as 2
>times
> > > their actual displacement because they fire on every stroke if one is to
> > > only count number of firings per revolution. Engines that run with an
> > > intermitant combustion cycle should be measured based on their total swept
> > > volume, not on the number of firings per revolution. Rotary and 2 stroke
> > > engines already have an advantage because they get more power strokes per
> > > revolution that the 4 stroke engines.
> > > Gary Allen
> > > ----- Original Message -----
> > > From: "Dave Dahlgren" <ddahlgren@snet.net>
> > > To: "Gary Allen" <gallen@relia.net>
> > > Cc: <land-speed@autox.team.net>
> > > Sent: Thursday, December 21, 2000 2:20 PM
> > > Subject: Re: mazda rotary engine factor
> > >
> > > > I did not even mention in my last reply what the issue
> > > > really is with the mazda rotary factor. It is currently
> > > > engine displacement times 3 for the class it has to run in.
> > > > This does not represent how the engine really works. it
> > > > takes 3 rev to complete 1 cycle for 1 rotor face. Typical
> > > > there are 2 rotors. This gives you 2 firings per rev the
> > > > same as a 4 cylinder piston engine. Each rotor face is 654
> > > > cc in a mazda 13b for example. That means that it processes
> > > > in 2 revs 654 X 2 rotors X 2 revs=2616 cc of air and fuel.
> > > > Exactly the same as a 2616 cc piston engine. Currently this
> > > > engine has a rating of 1308 X 3=3924 cc. I suspect it had to
> > > > do with the 3 faces on the rotors so everyone said just make
> > > > it times 3 or that it looks like it ought to be X 3....This
> > > > does not seem fair and reasonable to me. SCCA and FIA both
> > > > use an engine displacement Factor of just over 2 to adjust
> > > > the size of engines built like this when comparing them to
> > > > piston engines. In essence treating them the same as every
> > > > other 4 stroke engine by sizing them according to how much
> > > > air and fuel can be processed in 2 revs.
> > > > I would appreciate your thoughts on this matter
> > > > Dave Dahlgren
> > > >
> > > > Gary Allen wrote:
> > > > >
> > > > > I am not on the landspeed list but did know about the rule change
> > > suggestion
> > > > > from the rules meetings. It was rejected at the preliminary meeting
> > > because
> > > > > there was no data supporting the change. I am not sure where the
> > > request
> > > > > even came from and also not familiar with the current factor history
>or
> > > > > where it came from. Dan Warner is th best authority on the subject
>and
> > > its
> > > > > history.
> > > > >
> > > > > What is the issue / question? Gary
> > > Allen
> > > > > ----- Original Message -----
> > > > > From: "Dave Dahlgren" <ddahlgren@snet.net>
> > > > > To: <gallen@relia.net>
> > > > > Sent: Monday, December 18, 2000 1:33 PM
> > > > > Subject: mazda rotary engine factor
> > > > >
> > > > > > Wes Potter suggested i drop you a line about the current
> > > > > > dispalcement factor for Mazda Rotary engines.. Have you been
> > > > > > following the land=speed e-mail on this or do i need to
> > > > > > forward a bunch of it to you?
> > > > > > Dave Dahlgren
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