Rotary marine engine
J Dorval
standard marine engine with a rotary marine engine in an I/O
application?
Thanks
Jim Dorval
Earl Bollinger
http://www.rotarymarine.com
and see what they have to say about it.
Otherwise, the rotary engine is smaller, lighter, and more compact. It
does run at higher
RPM's thus you need a gear reducer or transmission of some sort.
Mazda used to sell rotary engine powered cars for a number of years, but
ran into problems, one of
which was EPA emissions requirements, and they dropped the engine from
their cars.
It's possible (especially in Calif and Oregon) that the rotary engine
along with the 2 strokes will
be banned from all waters in the forseeable future.
bajaman
damned if I can't find it though! They were working on using the Mazda 13B
turbo motor eventually too, if my memory serves. I had e-mailed them
inquring if they were thinking about using the last generation of RX7 engine
(255 hp from 73 cubic inches!) and they said not yet....... Privately I
have misgivings, as the rotaries have very little torque compared to a
reciprocating motor. I have had Mazda RX7's in the past and know this to be
true. They were great engines to bring up against the rev limiter (7000
rpm) and dump the clutch............Jesus those cars would move! But only
the turbo engines had any low rpm "grunt" to them.
Greg
"J Dorval" <dor...@netbistro.com> wrote in message
news:39BB3486...@netbistro.com...
Karl Denninger
The real issue is apex seals. There is no real way to avoid wear, and
there's also no way to rebuild/repair them.
These engines are light, high HP/displacement, and great - except that
they don't last. While some materials improvements might help that, it
would also drive the cost of the motor into the stratosphere.
--
--
Karl Denninger (ka...@denninger.net) Internet Consultant & Kids Rights Activist
http://www.denninger.net Cost-effective Consulting Solutions
http://childrens-justice.org Working to protect children's rights
In article <39BB858C...@worldnet.att.net>,
Larry W4CSC
wrote:
The Wankel was WAY inefficient and a gas hog in Mazda cars. It also
had bad lubrication problems and was quite short lived.
They got a better one, if anyone besides Caroll Shelby gets
interested. Take a look at a 104#, 8-cylinder, 16 power pulses per
rev, 210hp radical engine....only 104# and TINY!
I'd like to see this one run 10,000 hours to see how it acts......
larry
thu...@email.msn.com
While the low RPM torque is definitely an issue, once one is wound up it has
not problem staying wound up.
--
____
Todd Hudgel
Sulphur, LA
"bajaman" <wol...@hit.net> wrote in message
news:YzLu5.28796$3U2.1...@nntp3.onemain.com...
thu...@email.msn.com
an IB Rotary.
--
____
Todd Hudgel
Sulphur, LA
"J Dorval" <dor...@netbistro.com> wrote in message
news:39BB3486...@netbistro.com...
Gaétan Bolduc
that sand up front. :-)
"Larry W4CSC" <nob...@nowhere.net> a écrit dans le message news:
39bba901.6635307@news...
mjm3
> On Sun, 10 Sep 2000 00:13:10 -0700, J Dorval <dor...@netbistro.com>
> wrote:
>
> >Does anyone have any information about the possibility of replacing a
> >standard marine engine with a rotary marine engine in an I/O
> >application?
> >Thanks
> >Jim Dorval
> >
> The Wankel was WAY inefficient and a gas hog in Mazda cars. It also
> had bad lubrication problems and was quite short lived.
My '82 RX7 rotary engine was a sweetheart! It got 20+ MPG
for fuel efficiency, not bad compared to the 16 MPG I get today in my
Jeep Wrangler. And I still see 20 year old RX7s on the road today,
with way over 100K miles on them. The "bad lubrication" problems
were with the RX4, an earlier version.
Boy, would I love to replace the 2-stroke Merc in my Sugarsand Tango
with a Wankel. Purrrrr.....
Matt
LaBomba182
>From: ka...@FS.Denninger.Net (Karl Denninger)
>Date: 9/10/00 9:33 AM Eastern Daylight Time
>Message-id: <8pg2ip$bo1$0...@dosa.alt.net>
>
>The issue isn't emissions - that one was solved.
>
>The real issue is apex seals. There is no real way to avoid wear, and
>there's also no way to rebuild/repair them.
>
>These engines are light, high HP/displacement, and great - except that
>they don't last. While some materials improvements might help that, it
>would also drive the cost of the motor into the stratosphere.
>
>--
>--
>Karl Denninger (ka...@denninger.net) Internet Consultant & Kids Rights
should not respond to a post if you don't know what you're talking about Karl.
Mazda rotary's most certainly can be rebuilt and repaired. Why in the world
would you think they can not be? The apex seal issue was solved years ago. Sure
they wear, but then so do piston rings. Rotarys are still sold in Japan. And
they last just fine, if like any engine you take care of them. How do I know
this? Because I have a 1993 RX7 with 360 HP working toward 500 HP and it has
78,000 miles on it. And I have a friend who sold a nonturbo rotary with almost
200,000 miles on it and it ran fine. Stick with stuff you know Karl, like how
to screw your exwife.
Capt. Bill
hkr...@capu.net
Gee, the RX-7 is about the only interesting production car ever made in
Japan. I always liked them. Most of the rest of the Japanese cars I've
encountered are decently made and deadly dull.
--
Harry Krause
------------
A flashlight is a case for holding dead batteries
Karl Denninger
LaBomba182 <labom...@aol.com> wrote:
>>Subject: Re: Rotary marine engine
>>From: ka...@FS.Denninger.Net (Karl Denninger)
>>Date: 9/10/00 9:33 AM Eastern Daylight Time
>>Message-id: <8pg2ip$bo1$0...@dosa.alt.net>
>>
>>The issue isn't emissions - that one was solved.
>>
>>The real issue is apex seals. There is no real way to avoid wear, and
>>there's also no way to rebuild/repair them.
>>
>>These engines are light, high HP/displacement, and great - except that
>>they don't last. While some materials improvements might help that, it
>>would also drive the cost of the motor into the stratosphere.
>>
>>--
>>--
>>Karl Denninger (ka...@denninger.net) Internet Consultant & Kids Rights
> You really
>should not respond to a post if you don't know what you're talking about Karl.
>Mazda rotary's most certainly can be rebuilt and repaired. Why in the world
>would you think they can not be? The apex seal issue was solved years ago. Sure
>they wear, but then so do piston rings.
You can overbore a piston engine and install oversize pistons if you need
to during an overhaul.
You can't do that with a Wankel.
The apex seal issue *with regards to excess oil consumption* was solved.
The wear issue in general cannot be solved; its inherent in engine.
> Rotarys are still sold in Japan. And
>they last just fine, if like any engine you take care of them. How do I know
>this? Because I have a 1993 RX7 with 360 HP working toward 500 HP and it has
>78,000 miles on it.
78,000 miles on a car engine isn't all that much in terms of boat-service
hours. I have nearly that on my current Volvo and its just getting broken
in!
> And I have a friend who sold a nonturbo rotary with almost
>200,000 miles on it and it ran fine. Stick with stuff you know Karl, like how
>to screw your exwife.
> Capt. Bill
Give it a rest Bill, and cut the bullshit and personal insults.
One of my best friends is a former professional engine rebuilder. Everything
from car motors to big diesels with pistons the size of small children. This
guy used to be involved with the Automotive Engine Rebuilders Association -
yes, those folks, the guys who keep all the data, publish all the
bulletins - you know, the TRADE ASSOCIATION for the people who do this
for a living?
Yeah, them.
He hung up his tool box in favor of database programming and consulting (its
better money, quite frankly, and I don't blame him.) That doesn't change
his level of knowledge and real-world work experience, and he's the guy
I call when I have these kinds of questions.
I've talked with him about engine-related issues on several occasions,
including marine applications for them, including specifically the Wankels.
There are real wear issues with rotary engines and there is no solution to
them. Mazda solved half the problem, but not the rest. The emissions issue
is real, the efficiency problems are real, and the rebuild limitations are
real.
I think they might be interesting in a boat, provided you could get
reasonably-priced gear-reduction (you'll need it; they like to rev a lot
higher than conventional piston engines), and provided that the efficiency
issues can be resolved in the boat's normal operating band (which is at
a MUCH higher power level than in a car; it may be that they are ok
efficiency-wise in a marine application)
But you DO have to expect to toss 'em when they wear out.
Is this a big deal? That depends on how much they cost, doesn't it?
You would THINK that Mazda could make a KILLING on these things if they were
to marinize them. After all, with the fewer moving parts and simpler
structure, as well as the lighter weight and smoother operation, you'd think
they could sell them at a hell of a discount to traditional marine blocks.
But its not happening.
Obviously there's a reason for this.
--
--
John Krulik
"Karl Denninger" <ka...@FS.Denninger.Net> wrote in message
news:8phaga$rrf$0...@pita.alt.net...
. After all, with the fewer moving parts and simpler
> structure, as well as the lighter weight and smoother operation, you'd
think
> they could sell them at a hell of a discount to traditional marine blocks.
>
> But its not happening.
>
> Obviously there's a reason for this.
Having had a couple RX7's I could see a few problems that would require
some engineering to resolve:
1. The engine has very low torque
2. The exhaust is very hot - could present problems with thru hull exhaust
3. Not only is the exhaust very hot but it is very very loud. Serious
mufflers would be required.
thu...@email.msn.com
> Gee, the RX-7 is about the only interesting production car ever made in
> Japan. I always liked them. Most of the rest of the Japanese cars I've
> encountered are decently made and deadly dull.
>
How about 240, 260, 280Z? The ZX and early 300 series were deadly dull, but
reliable. My '84 300 turned an average lap of over 100 MPH after 187,000
miles, before security stopped me. : ) The next lap would have been 120 for
sure.
thu...@email.msn.com
--
____
Todd Hudgel
Sulphur, LA
<thu...@email.msn.com> wrote in message news:e6UxdH5GAHA.369@cpmsnbbsa07...
Karl Denninger
John Krulik <kru...@mindspring.com> wrote:
>
>"Karl Denninger" <ka...@FS.Denninger.Net> wrote in message
>news:8phaga$rrf$0...@pita.alt.net...
>. After all, with the fewer moving parts and simpler
>> structure, as well as the lighter weight and smoother operation, you'd
>think
>> they could sell them at a hell of a discount to traditional marine blocks.
>>
>> But its not happening.
>>
>> Obviously there's a reason for this.
>
>Having had a couple RX7's I could see a few problems that would require
>some engineering to resolve:
>1. The engine has very low torque
Solvable with either a torque converter (yes, I'm serious) or a
gear-reduction transmission.
>2. The exhaust is very hot - could present problems with thru hull exhaust
The exhaust is very hot on any IC engine. Water injection is required for
most to avoid melting things (or starting fires) as it sits.
>3. Not only is the exhaust very hot but it is very very loud. Serious
>mufflers would be required.
Not if you exhaust underwater.
BTW, I've heard a rotary with the muffler off. Yeah, it is loud. WOW!
LaBomba182
If you want to see what real bullshit is reread your first post.
>>>there's also no way to rebuild/repair them.
>>>These engines are light, high HP/displacement, and great - except that
>>>they don't last.
200,000 is an engine that doesn't last?
I was not
responding to your post as to the suitability of the rotary engine in a marine
application. I was responding to your obvious lack of personal knowledge in
regard to rotary engines. And your follow up post just confirmed that.
And
as far as >personal insults.< go,
I was correct, you didn't know what you were talking about and you do know how
hkr...@capu.net
Ahh, the 240Z...add that to the very brief list of Japanese cars I find
interesting.
--
Harry Krause
------------
Suicide stunts your growth
George Jefferson
:How about 240, 260, 280Z? The ZX and early 300 series were deadly dull, but
:reliable. My '84 300 turned an average lap of over 100 MPH after 187,000
:miles, before security stopped me. : ) The next lap would have been 120 for
:sure.
ah, my 80zx ticked over 200,000 @ 100+. Burned more oil than a
2 stroke though <g>
--
george jefferson : geo...@sol1.lrsm.upenn.edu
to reply simply press "r"
-- I hate editing addresses more than I hate the spam!
Karl Denninger
George Jefferson <geo...@sol1.lrsm.upenn.edu> wrote:
>:
>:How about 240, 260, 280Z? The ZX and early 300 series were deadly dull, but
>:reliable. My '84 300 turned an average lap of over 100 MPH after 187,000
>:miles, before security stopped me. : ) The next lap would have been 120 for
>:sure.
>
>ah, my 80zx ticked over 200,000 @ 100+. Burned more oil than a
>2 stroke though <g>
Exactly my point.
--
--
George Jefferson
:>ah, my 80zx ticked over 200,000 @ 100+. Burned more oil than a
:>2 stroke though <g>
:
:Exactly my point.
the z's are not rotaries by the way. I dont know how we digressed there.
It sipped oil compared to the 350chev I had before it. Evidence
only that yes you really need to change your oil once in a while.
Tom Brown
> >1. The engine has very low torque
>
> Solvable with either a torque converter (yes, I'm serious) or a
> gear-reduction transmission.
You have no idea. A torque converter converts engine torque into hydraulic
pressure. To redrive a boat with a hydraulic system would be inefficient and
expensive. Anyone with a clue would just run a lower pitch prop. The torque may
be lower, but the power is similar. If you have extra RPM, you can turn that into
torque by lowering the gear ratio, thus providing mechanical advantage. The
differences could easily be handled by a correctly engineered propeller and/or
gear ratio.
> >2. The exhaust is very hot - could present problems with thru hull exhaust
>
> The exhaust is very hot on any IC engine. Water injection is required for
> most to avoid melting things (or starting fires) as it sits.
Karl, it is clear that you have no idea about rotary engines. They run much
hotter than piston engines. They expel hot gasses every revolution and they
typically rev much higher. Stainless steel will not last very long in the exhaust
system of a rotary engine due to the heat involved.
> BTW, I've heard a rotary with the muffler off. Yeah, it is loud. WOW!
You probably heard a rotary that vents it's exhaust prior to the thermal reactor.
That would be comparable to listening to a piston engine with open exhaust
manifolds. Open manifolds on a piston engine are not quiet either.
I believe that many people don't like the rotary engines because they don't
understand them. That's fine, but there is a lot of misinformation floating
around that is based on ignorance. Too bad because rotary technology is really
interesting. They can develop huge amounts of power for their size and weight
(basically limited by the amount of heat they can dissipate), they are shockingly
simple and they can run at very high RPMs for long periods of time.
Captain Bill was siting an engine that had 78000 miles on it. That would be no
big deal, but read what he said. He has 'suped' it up. He has a 13b engine with
360 horse power. That's 1.3 liters of displacement and 360 horse power. Think
about it. Sure, it fires on every revolution, but that's still only the
equivalent of 2.6 liter. 360 horsepower for a 2.6 liter (equivalent) engine...
still pretty impressive. How many piston engines can produce 275 hp per liter and
last a decent life? What's more, Bill's engine sounds like it is far from being
at the end of it's life. He'll probably get a lot more miles on it, even in this
configuration.
Some of the experimental aviation guys have had great luck with the Mazda 13b
engine. There is a tiny worm gear oil pump that is prone to failure. These guys
typically don't trust it, so they premix their oil. Sound familiar? With carbs
and premixed oil, there are only three moving parts. No kidding. Two rotors and
a worm shaft. These guys have good takeoff roll and good cruising speed, too.
From a performance point of view, there are no disadvantages to running a rotary.
Rotaries tend to be not quite as fuel efficient as a piston engine due to thermal
inefficiencies, but the fuel consumption is still better than any of the aviation
certified engines (just not as good as the some of the other auto engine
conversions).
With a lake full of cooling water, rotary engine technology would probably be a
wonderful match for marine use. It's too bad there isn't more development
happening on this platform.
Regards,
Tom Brown
Karl Denninger
>Karl Denninger wrote:
>
>> >1. The engine has very low torque
>>
>> Solvable with either a torque converter (yes, I'm serious) or a
>> gear-reduction transmission.
>
>You have no idea. A torque converter converts engine torque into hydraulic
>pressure. To redrive a boat with a hydraulic system would be inefficient and
>expensive. Anyone with a clue would just run a lower pitch prop. The torque may
>be lower, but the power is similar. If you have extra RPM, you can turn that into
>torque by lowering the gear ratio, thus providing mechanical advantage. The
>differences could easily be handled by a correctly engineered propeller and/or
>gear ratio.
Yes and no.
Rotary engines don't have much low-end "grunt". Without a turbocharger
there's no good way to really fix that; thus, the suggestion for a torque
converter (turn rotational energy at a higher RPM into more torque at a
lower one)
I've driven rotary Mazdas, and am very aware of their torque curve. Its
very unlike traditional piston engines, but they really like to rev, and
their horsepower potential is really only limited by their ability to
breathe, since there are no reciprocating parts to come apart.....
>> >2. The exhaust is very hot - could present problems with thru hull exhaust
>>
>> The exhaust is very hot on any IC engine. Water injection is required for
>> most to avoid melting things (or starting fires) as it sits.
>
>Karl, it is clear that you have no idea about rotary engines. They run much
>hotter than piston engines. They expel hot gasses every revolution and they
>typically rev much higher. Stainless steel will not last very long in the exhaust
>system of a rotary engine due to the heat involved.
Sure it will. Same deal you have with piston engines now; you water-cool
the exhaust manifold and inject water into the downstream side of the
riser on the way out. It runs hotter, you use more cooling water flow.
There happens to be a LOT of it under the boat, you know :-)
>> BTW, I've heard a rotary with the muffler off. Yeah, it is loud. WOW!
>
>You probably heard a rotary that vents it's exhaust prior to the thermal reactor.
>That would be comparable to listening to a piston engine with open exhaust
>manifolds. Open manifolds on a piston engine are not quiet either.
Correct. Been there, heard that.
>They can develop huge amounts of power for their size and weight
>(basically limited by the amount of heat they can dissipate), they are shockingly
>simple and they can run at very high RPMs for long periods of time.
Yes, they do all those things. But their torque curve is not great off the
top, which means you need additional mechanical stuff to handle translation
of RPM into torque (at a given horsepower, either can be changed into the
other)
>Some of the experimental aviation guys have had great luck with the Mazda 13b
>engine. There is a tiny worm gear oil pump that is prone to failure. These guys
>typically don't trust it, so they premix their oil. Sound familiar? With carbs
>and premixed oil, there are only three moving parts. No kidding. Two rotors and
>a worm shaft. These guys have good takeoff roll and good cruising speed, too.
Aircraft are a different matter. Variable pitch propellors solve the torque
problem, since you just spin up the engine. But those things are expensive
on boats - I have one, and love it, but how many people have 'em?
There are solutions to this available for boats, but they're not mainstream,
they're expensive, maintenance prone and problematic for many installations.
On the other hand, the weight issue might not be nearly such a big deal with
a Wankel, since the engine is so light to begin with.
>With a lake full of cooling water, rotary engine technology would probably be a
>wonderful match for marine use. It's too bad there isn't more development
>happening on this platform.
Limited, single-source supply, limited demand = no development.
LaBomba182
>From: ka...@FS.Denninger.Net (Karl Denninger)
>In article <8pitb5$qvk$1...@netnews.upenn.edu>,
>George Jefferson <geo...@sol1.lrsm.upenn.edu> wrote:
>>:
>>:How about 240, 260, 280Z? The ZX and early 300 series were deadly dull, but
>>:reliable. My '84 300 turned an average lap of over 100 MPH after 187,000
>>:miles, before security stopped me. : ) The next lap would have been 120 for
>>:sure.
>>
>>ah, my 80zx ticked over 200,000 @ 100+. Burned more oil than a
>>2 stroke though <g>
>
>Exactly my point.
>
>--
>--
>Karl Denninger (ka...@denninger.net)
Zs aren't rotaries. And rotaries are oil injected.
That's one reason uniformed people think they burn oil. You would not say an
oil injected outboard "burns" oil excessively. And by the way Karl you were
right, there was no good reason for my "you know how to screw your ex-wife"
crack even if I think that to be true. I was wound up yesterday and I get tired
of seeing people respond to questions posted with no direct knowledge on the
subject being discussed. And giving an answer based on hearsay only. So you
have my apology for that crack. But I stand by the rest of what I stated.
Capt. Bill
LaBomba182
Thanks Tom for showing the patience and eloquence I lack. And trying to educate
the ignorant. Like I said in my other post, I get tired of people with no first
hand knowledge of a subject posting an authoritative sounding answer to that
question. And by the way my rotary uses no more oil than is normal and I do mix
in a small amount of Red Line 2 cycle oil with every gas fill.
Capt. Bill
Tom Brown
> The torque may
> >be lower, but the power is similar. If you have extra RPM, you can turn that into
> >torque by lowering the gear ratio, thus providing mechanical advantage. The
> >differences could easily be handled by a correctly engineered propeller and/or
> >gear ratio.
>
> Yes and no.
Make that yes.
> >They can develop huge amounts of power for their size and weight
> >(basically limited by the amount of heat they can dissipate), they are shockingly
> >simple and they can run at very high RPMs for long periods of time.
>
> Yes, they do all those things. But their torque curve is not great off the
> top, which means you need additional mechanical stuff to handle translation
> of RPM into torque (at a given horsepower, either can be changed into the other)
Sure, and so do piston engines. What do you think is in the bullet portion of you
lower unit? Let's see how well your boat performs with a 1:1 drive-line ratio. So
what if the rotary will optimally use a different ratio than a piston engine? Both
require mechanical gearing to provide optimal performance. The complexity is not
increased.
> Aircraft are a different matter. Variable pitch propellors solve the torque
> problem, since you just spin up the engine. But those things are expensive
> on boats - I have one, and love it, but how many people have 'em?
You are spreading misinformation on a topic about which you know nothing. Chuck Graham
uses a 13b engine in a Long-EZ Canard airframe with a fixed pitch wooden propeller. I
don't recall the dimensions of his prop. A plane that can be effectively powered by a
165 hp engine is not a plane that is likely to have a variable pitch propeller.
Chuck's plane performs very well indeed. As I recall, his take-off roll is about
800'. That's better than the spec that was done with Lycoming power. His cruise speed
is greater than the factory specified also, at 180 mph.
The aviation application is not that different from a marine application. The aviation
engine will be under load for a much, much longer period of time as it has a much
larger climb-out than a boat does. Still, there are similarities to the performance
requirements. There is the heavy thrust requirement. Believe me, when the throttle of
an airplane is firewalled, the engine sees a serious load. I don't know how this would
compare to a boat, but I would assume it to be greater than or equal to the load on a
boat engine on take-off. There is the high reliability requirement. Fresh water boat
don't share this requirement to the same degree as planes, but the rotary's simplicity
and reliability are a great benefit to marine use. Lastly, there is the requirement to
rev and high rates for indefinite periods. This is the big one. Not all engines can
run at near red-line speeds for an indefinite period with much longevity.
> Karl Denninger (ka...@denninger.net) Internet Consultant & Kids Rights Activist
> http://www.denninger.net Cost-effective Consulting Solutions
> http://childrens-justice.org Working to protect children's rights
Tom Brown
Karl Denninger
>Karl Denninger wrote:
>
>> The torque may
>> >be lower, but the power is similar. If you have extra RPM, you can turn that into
>> >torque by lowering the gear ratio, thus providing mechanical advantage. The
>> >differences could easily be handled by a correctly engineered propeller and/or
>> >gear ratio.
>>
>> Yes and no.
>
>Make that yes.
>
>
>> >They can develop huge amounts of power for their size and weight
>> >(basically limited by the amount of heat they can dissipate), they are shockingly
>> >simple and they can run at very high RPMs for long periods of time.
>>
>> Yes, they do all those things. But their torque curve is not great off the
>> top, which means you need additional mechanical stuff to handle translation
>> of RPM into torque (at a given horsepower, either can be changed into the other)
>
>Sure, and so do piston engines. What do you think is in the bullet portion of you
>lower unit? Let's see how well your boat performs with a 1:1 drive-line ratio. So
>what if the rotary will optimally use a different ratio than a piston engine? Both
>require mechanical gearing to provide optimal performance. The complexity is not
>increased.
Correct.
>> Aircraft are a different matter. Variable pitch propellors solve the torque
>> problem, since you just spin up the engine. But those things are expensive
>> on boats - I have one, and love it, but how many people have 'em?
>
>You are spreading misinformation on a topic about which you know nothing. Chuck Graham
>uses a 13b engine in a Long-EZ Canard airframe with a fixed pitch wooden propeller. I
>don't recall the dimensions of his prop. A plane that can be effectively powered by a
>165 hp engine is not a plane that is likely to have a variable pitch propeller.
>Chuck's plane performs very well indeed. As I recall, his take-off roll is about
>800'. That's better than the spec that was done with Lycoming power. His cruise speed
>is greater than the factory specified also, at 180 mph.
>
>The aviation application is not that different from a marine application.
Yes it is.
Air compresses FAR more than water. A propellor on an airplane turns at a
higher percentage of top RPM at rest than a boat propellor (neither moving.)
In effect, the aviation application gets its "torque multiplication" by
slippage; an effect the boat cannot have without either variable drive
ratios, variable propellor pitch, or a torque convertor similar to an
automatic transmission's.
>and reliability are a great benefit to marine use. Lastly, there is the requirement to
>rev and high rates for indefinite periods. This is the big one. Not all engines can
>run at near red-line speeds for an indefinite period with much longevity.
On that point you are correct; rotary engines do not suffer from extended
high-RPM operation, as there are no reciprocating components.
--
--
thu...@email.msn.com
changes. Amazing, but slow car. The original "Star Wars" digital dash still
worked perfectly too.
--
____
Todd Hudgel
Sulphur, LA
" George Jefferson " <geo...@sol1.lrsm.upenn.edu> wrote in message
news:8pitb5$qvk$1...@netnews.upenn.edu...
bmc...@ti.com
the Mazda engineer came to the department and gave a talk on the rotary
engine. summarized, he said if no emissions controls, the engine is the
best. There were seal problems at first, but better living through
chemistry and ceramics solved that problem. The emissions required extra
oil being sprayed inside the piston to keep temps down, etc. Made for some
reliability problems and hurt power output. My dad bought an Evinrude
snowmobile with 35 HP Wankle engine in about 1971. Awesome performer. I
think the 35 HP was a big understatement.
Bill
Karl Denninger <ka...@FS.Denninger.Net> wrote in message
news:8pg2ip$bo1$0...@dosa.alt.net...