Once a month SZP opens the airport for visitors. Those of us with
unusual air planes open our hangar doors and people stroll by and
ask questions. Many are questions I have heard over and over again.
The rotary powered RV4 with the cowl off is prominent and draws a
lot of people,
I am scheduled to give a talk about rotaries at AusFly in Narrowmine
NSW Aus next week. To speed the process I am getting a large poster
printed with some of those questions.
Here is a preliminary version. Comments are welcome.
Paul Lamar
Paul,
You know far more about rotary engine durability than I do, but you
continue to bury your head in the sand when it comes to the fuel
efficiency of rotary engines--at least when it comes to cars. The
fact of the matter is that rotaries use 20-30 percent more fuel than
comparable, modern piston engines. That's why even Mazda has given
up on them. The proof of this is incontrovertible and as a rational
engineer, you should accept this fact. That shortcoming doesn't
disqualify the rotary as an aircraft engine, where its other
virtues--light weight, compact size, smoothness, and
durability--might be more important.
Csaba Csere
The BSFC is now within 5% of a piston engine
The car problem has more to do with the gear box chosen by Mazda
than the BSFC of the rotary.
My RX8 is doing 3000 rpm at 80 while my 250 HP Honda Odysseys is
doing 1800 RPM. This the same reason the 400 HP Corvette gets 25 MPG
on the free way. My 1994 Mercury Cougar was doing 1900 at 80 MPH.
At a steady 70 MPH the RX8 is getting 25 MPG. The same as my old RX2
and the two RX7s I have owned. All had the wrong gearing.
All you need do is look at the OBD data attached.
Another factor is when the Mazda computer leans the engine and when
it does not. Leaning improves the BSFC. Honda circumvents the NOX
emissions laws by not leaning the engine during the smog test. The
rest of the time they lean it frequently. Nox is a big problem for
diesels as nox increases when running lean. Mazda never leans the
RX8 engine no matter what.
I have developed and patented a high speed MSD ignition system that
I hope will knock a few points off of the BSFC.
The exhaust valve, in a 4 stroke, waste 20% of the of the
recoverable energy in turbo compound use. The exhaust normally waste
50% of a gallon of gas. Harvesting in F1 speak. A turbo compound
rotary would therefore become the most efficient IC in the world
maybe short of some diesels.
The F1 hybrid scheme is not the most efficient for free way use,
http://www.rotaryeng.net/Oxford-TC-talk.mp4
If Mazda does not build a turbo compound rotary they are not
informed.
Mercedes, Renault , Ferrari and Honda will.
We now have a RB 650 HP 2 rotor that weighs less than 200 pounds in
a time to climb project air plane. It has a controlled leak in the
exhaust manifold because there is too much energy in the exhaust. In
other words it would over boost the engine. This is in addition to
the waste gate.
Mazda ought to hire me as a consultant. I would straighten them out
damn quick :-)
Paul Lamar
Paul,
The rotary has relatively short gearing because it has little
low-rpm torque and if the gearing were any taller, it would have no
acceleration in top gear--at least with a manual. Most of the other
cars you quote are non -porting and have automatics, so they kick
down when you floor the accelerator.
Also, there are other cars with similar gearing to the Mazda, such
as a BMW 335i. But that car gets better mileage--over 30 mpg at 70
mph--while delivering far more performance--in a much heavier car.
As to the Honda leaning out during off-cycle driving, I don't know
what your car does, but such a calibration would be highly illegal
and I doubt that Honda, or anyone else, uses it.
Your turbo-compound rotary idea has merit, but it says nothing about
the efficiency of real-world rotaries.
Csaba
Of course. It does need an automatic manual. (Computer controlled hyd
shiifting}.
30 MPG verses 25 MPG is 20% not 30%. My neighbour has an M3 and I
will ask about the 80 MPH RPM.
The piston engine has millions of more hours of R & D. Due to new
apex seal materials the leaning angle can be increased allowing a
higher compression ratio or a better combustion chamber shape.
I had the OBD II on the Honda and I saw a lot of situations where it
went way lean. The gov only cares about the arbitrary driving cycle
and they don't peer over the shoulders of the company EFI
programmers. From a software point of view it is easy to detect the
silly driving cycle.
The nox v BSFC situation was discussed in Bruce Briggs book War
against the Automobile.
Paul Lamar
What is not real world about turbo compound. CW made thousands of
R3350 TCs. A Super Connie could stay aloft for 24 hours. Actually the
exhaust valve was the Achilles heel. The head would come off and take
out the turbine. Rotary no problem no exhaust valves.
Paul Lamar
"As to the Honda leaning out during off-cycle driving, I don't know
what your car does, but such a calibration would be highly illegal
and I doubt that Honda, or anyone else, uses it."
Csaba Csere
Hey Csaba, Looks like VW was caught doing just exactly that. See
the attached jpg.
Paul Lamar
I have to wonder if this is what Mazda has been referring to when
asked about introducing diesel engines to the North American market.
They have referred to overcoming performance issues to get
performance to the standard they desire to be up to the Zoom Zoom
standard. Looks like VW cheated and have been caught at it. Makes
Mazda look good by playing the game by the rules. EPA standard has a
test regimen that defines the exact parameters required on a test
dyno. I bet that will be changed to include a road test on different
roads so as to eliminate the possibility of programming a software
bypass during testing with active testing as was done to catch VW.
And the consumer will pay more to breath clean air.
Dale Davies
A lot more in the case of the carcinogenic diesel.
Paul Lamar
I don’t know what performance issues Mazda is having with their diesel.
But they are using what I refer to as a Giesel (no Toyota connection)
engine because the Sky Active tech results in a gas motor with higher
than usual CR and a diesel with lower than usual CR, allowing Mazda to
use the same block for both.
So I guess you could call Sky Active the New Kid on the Block . . . or
maybe knock . . .
I think what VW was
/subtly/ telling the EPA and the ARB is that when it
comes to diesel emission regs, they can shove it up the tail pipe.
john dinkel
Good luck using the same block. Don't forget the pig piss :-)
Neil, are you saving your pig piss? There is a world wide market for it :-)
Paul Lamar
Paul, 6500 pigs by 2 litres of pig Piss daily, (estimated!) at whatever, I
am knee deep in clover or gravy whatever you are familiar with. Orders
taken anytime. Would not recommend the boar piss for even being in pigs
(swine or hogs) for 40 years plus, they still take your breath away!
Now as to the bulls droppings in all this, like I quoted before, there
are 285,000 molecules in a given volume of atmosphere. 80% is nitrogen,
18%
is oxygen which leaves 2% or 5700 molecules for the "rest". Divide all the
"rest" up into the various components and when you get to CO2 you have just
33 molecules. It is suggested that 2 of these may be a result of human
action or cattle farting, whatever, but the bottom line suggests that 2
molecules out of 285,000 must have magical powers to affect anything!
Then don't forget that the latest thing in agriculture is to use the
exhaust gas as fertilizer. We are actually on this now for the 3rd year
and
finding it extremely profitable, no artificial fertilizer saving us over
$500,000 per year! Google Bioagtive to see for yourself, Global warming,
now changed to climate change to force the picture---- Ho hum just follow
the money to see who is peddling this garbage.
Meanwhile I will keep burning this horrible fuel in my rotary. Neil.
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