31 replies to this topic

[StickShift]

Iwas having a pretty interesting read over at Howstuffworks.com and came upon an article on Rotary Engines. Rotary engines have always been a mystery to me, I remember wondering how they worked a couple years back when I realized a rotary engine is the kind that the Mazda RX-7 used. All I've known for a while was that it wasn't similar at all to the normal stroke engine we all know. Anyway, my interest was sparked again today when I noticed that the Le Mans winng Mazda Group C 787B also used a Rotary engine. I know that the Group C cars, especially the Mazda had incredible accelearation and top speed, coming very close to a Formula 1 car in comparison.

now, these are the things that I was wondering:

1. Could a Rotary Engine be placed in a Formula 1 car in theory and match the performance of a current Formula 1 engine?

2. Just how big would this Rotary engine have to be to power the car?

3. Would the size of the engine be an issue?

4. Has a rotary engine been used before? when?

[AS110]

In the 70's when I worked for a Mazda dealer we had a saying about the rotaries

The size of a 4 cyl
The power of a 6 cyl
The thirst of a V8

I think fuel economy would be the biggest problem.A normaly aspirated rotary that put out enough power for F1 (4 rotor?) would use as much fuel as Concorde on take off.

Some wierd power delivery aspects too - kind of like a 2stroke,poor low end,no engine braking.

Rotary drivers need to wear their caps backward and bob their heads,no F1 drivers can do this at this stage.

Hey,what motor sports doesn't use the left hand,slot cars? I'm left handed and use the controller in my right hand.

[GunStar]

Regretably, the Concorde Agreement limits the engines to 3L 4 stroke V-10s until 2008. A rotary engine wouldn't be a very formidable challenger to current F1.

Unlike F1, a rotary can only get up to about 10,000rpm before you count the lifespan of the engine in MINUTES!!! No joke, a normal 13B is rated up to 8500rpm, and can go 70,000 km, a engine ripped up to 9000 can maybe get 10k to 15k klicks. At 9500, you might get 4 hours or so. Top of about 1000 klicks. Now, this is sustained for some amount of time. Not much, but maybe 10 or 15 seconds a lap. The common 13B is a two rotor engine that can get about 250HP with a little porting and tuning. I can build a 13B with twin turbos pushing 2.2bar, at 9000rpm and get in the neighborhood of 500HP. This is a pure racing motor. Lasts about 2 weekends for normal SCCA events. With the quad rotor 13J, I've heard of 600HP at 9000rpm without turbos.

Since a 13B rotary is "Technically" a 1.2L engine, but equivelented out to 2.4L, and the 13J is a 2.5L equaled to 5L, F1 would probably can it on that arguement. But if allowed to turbo a 13J, they could probably get about what current F1 gets. Another question is about engine materials. Nobody has really tried to strenghten a 13B block with the new stuff that people have...carbon fibre, beryllium, ect.... Wonder how long they'd last with that?¿

And the thirst issue. I wouldn't say as bad as a V-8, but definently, a good 3.8 or 4.2 V-6. Major advantage of a rotary is the CG and weight issues. And the rotary gives power INSTANTLY. No lag. I can set up a turbo 13B to respond as fast as any NA 4 stroke engine.

Oh, and woe be you if you miss a shift. Depending on how bad you blow it, you may just kill a few thousand klicks from your engine, or.......the output shaft vibrates enough and the rotors can go out of whack, or fly OUT of the block!!! Grenading a rotary is a BAD thing to do. Very expensive, may even damage the chassis.

[Viss1]

Originally posted by GunStar
Another question is about engine materials. Nobody has really tried to strenghten a 13B block with the new stuff that people have...carbon fibre, beryllium, ect.... Wonder how long they'd last with that?

I think that's the key. I'm sure that with a little unobtanium, the apex seals could handle a little detonation.

I have a great respect for rotarys. The main reason the manufacturers shyed away from them was emissions regulations, followed closely by fuel economy.
I'm off to find out more about how Mazda built that LeMans engine...

[ehagar]

I own a RX7, and love the thing dearly (if you follow a rigid maintenance program they can last a long time) but can't imagine a F-1 engine out of a rotary...

Less parts than a conventional, but what would be the difference in rotating mass and inertia between a regular and a rotary? Off hand, I would have no idea...

When I went to university, at a hydrogen energy seminar, I was interested in a presentation where a 13B that was modified to run on Hydrogen.... I thought that was pretty cool. It worked quite well, although the power output was obviously lower...

Check out http://www.monito.com/ to learn more about rotaries, Felix Wankel's creation...

[Melbourne Park]

My Godfather had one of the first Maxda rotary cars in Australia. He was a school teacher, the car before the rotary was a Morris 1100. The car was a four door sedan. He drove it for years, and never had any problems with it. No seal issues whatsover ... I asked him how come? And he said the manual said to warm the engine in for several minutes before driving the car. He always did that he said ...

As to Hydrogen rotaries, Mazda have a fleet of hydrogen MX5s in Japan, the engine being a rotary. That's one way to get around fuel consumption issues, go hydrogen!

In Australia we've now got a "factory" turbo MX5 - sorry for US people, - Miata - and it develops 150kw and 285 NM of torque. It goes from 0 to 62 MPH a bit of 6 seconds. The car weighs almost the same, and has about 250 replacement parts. The air bits are all carbon fibre. But of course, its not a rotary. And of course, there's a type of Miata made in Brisbane, where they attach lots of Miata to a whole lot of RX7 parts - the gearbox, diff etc., but they don't put in the RX7's rotary, which I guess means those engines may not have been that reliable. Instead, this company puts in a Lexus 4 litre V8, and the car is quite quick. Evidently the V8 sounds very aggressive, unlike the luxery car version; there's also a super charged version, and that car is seri.ously quick.

At least the supercharger goes in a rotary direction!

[Viss1]

Originally posted by Melbourne Park
Instead, this company puts in a Lexus 4 litre V8, and the car is quite quick.

There are companies in the States installing the old 5.0L Ford V8 in Miatas.

[tedmna]

Originally posted by Viss1




There are companies in the States installing the old 5.0L Ford V8 in Miatas.

Remember the 928 powered Golf of about 1985 vintage built by some long lost german company!

[GunStar]

Now, try a 13B in a little Triumph.....

[Yelnats]

Gunstar said, "Unlike F1, a rotary can only get up to about 10,000rpm before you count the lifespan of the engine in MINUTES!!!

Try 10k in your Ford V8 and see how long it lasts! The point being a rotary due to it's inherent balance & smoothness has the potential to rev far beyond any reciprocationg engine. If F1 designers can make a bunch of connecting rods & pistons fling themselves around at 18k, reaching 20k with a rotary should present little challenge.

And I believe Lotus played around with a F1 rotary during their Indy Racing period. It was called a Gas Turbine!

[berge]

As someone who has, ahem, "blown up", a couple of 13B's in his time, I would like to add the following observation about my experiences with this gem of a motor.
"fantastic concept, poor execution".

[ehagar]

Originally posted by berge
As someone who has, ahem, "blown up", a couple of 13B's in his time, I would like to add the following observation about my experiences with this gem of a motor.
"fantastic concept, poor execution".

I guess I've been lucky... No problems at all. 160,000 km and still runs great.

[berge]

n.a or turbo? any track use?

[ehagar]

Generation II N.A. for everyday use. Religiously maintain it. Works great. The only problems I've had is when I've gone to a dealer! Don't trust them anymore...

A friend of mine had a Generation III... he had problems with the Turbo. The turbo hoses, when hot began to contract and restricted the engine...

Replaced a few components with aftermarket parts and never had problems again.

[AS110]

Nobody uses small block Chevs in F1,and a Mazda 13B won't be used in F1.

There are model aircraft wankels that run at 20,000 rpm,and larger wankels are used in full sized aircraft too.So I don't see rpm and reliability being a problem to designers in the F1 league.

One company I worked for used the Sachs wankel on the fridge motors for long haul refridgerated freight trucks,they could go from Christchurch to Auckland on half a gallon of fuel (stopped on the Cook Straight) and we could fit them with one hand,not the 3 or 4 guys needed for the 4 strokes.

Another company I was with(large cv) used them on hire mowers.The customers soon found out about the huge power output.They would rotary hoe a new section,then hire a mower,turn the blade upside down and level the ground!We had to pull them out of service.

I have nothing at all against rotaries,just the wankels that drive them

[Melbourne Park]

Originally posted by AS110
Nobody uses small block Chevs in F1,and a Mazda 13B won't be used in F1.

There are model aircraft wankels that run at 20,000 rpm,and larger wankels are used in full sized aircraft too.So I don't see rpm and reliability being a problem to designers in the F1 league.

One company I worked for used the Sachs wankel on the fridge motors for long haul refridgerated freight trucks,they could go from Christchurch to Auckland on half a gallon of fuel (stopped on the Cook Straight) and we could fit them with one hand,not the 3 or 4 guys needed for the 4 strokes.

Another company I was with(large cv) used them on hire mowers.The customers soon found out about the huge power output.They would rotary hoe a new section,then hire a mower,turn the blade upside down and level the ground!We had to pull them out of service.

I have nothing at all against rotaries,just the wankels that drive them

Good post. I had forgotten about all the utlra light and military Wankels, such as the Norton etc.

[berge]

Originally posted by ehagar
Generation II N.A. for everyday use. Religiously maintain it. Works great. The only problems I've had is when I've gone to a dealer! Don't trust them anymore...

A friend of mine had a Generation III... he had problems with the Turbo. The turbo hoses, when hot began to contract and restricted the engine...

Replaced a few components with aftermarket parts and never had problems again.

good for you. I blew my motors due to heavy track use, but still, was disappointed with the lifespan of the motor.
don't talk to me about a 3rd gen rx-7. it's more temperamental, requires more upkeep and more maintenance than a pre-90's ferrari.

what exactly have you modified on your car. By the time I sold it, I had done basically everything you could do to a n.a. 13b., If you're interested, I can tell you what works and what does'nt. Always had the car on a chassis dyno to see results after modifications. expensive, but worth it if you want to see what really works.

[GunStar]

Now, did you play nice with the motor, or just go for broke¿ I don't suggest trying to hit the red line very often in a rotary since there is NO rev limiter. The thing will just keep going as long as it can, as fast as it can. The output shaft can't take the strain from more than 10k rpm. Now, I've never worked with anything but the 12As and 13Bs. Other designs may be able to last to 20k or more but not the street engine.

If you treat the engine correct and don't race it too much or too hard, they're a dream to own. They can last up to 160,000km as ehagar noted. Miss shifts often, play stoplight warrior, or just try to see how high it will rev, and you strip klicks off the lifespan.

[berge]

Originally posted by GunStar
Now, did you play nice with the motor, or just go for broke¿ I don't suggest trying to hit the red line very often in a rotary since there is NO rev limiter. The thing will just keep going as long as it can, as fast as it can. The output shaft can't take the strain from more than 10k rpm. Now, I've never worked with anything but the 12As and 13Bs. Other designs may be able to last to 20k or more but not the street engine.

If you treat the engine correct and don't race it too much or too hard, they're a dream to own. They can last up to 160,000km as ehagar noted. Miss shifts often, play stoplight warrior, or just try to see how high it will rev, and you strip klicks off the lifespan.

me? not be nice to a motor?
EFI 8500RPM rev-limiter. daily-driver/weekend road racer. Got about 70000Km and about 30 track days at Mosport, Shannonville and Watkins Glen out of it. Found it's high fuel consumption relative to torque production, exhaust noise level, and, zero-tolerance of overheating or detonation unacceptable for my needs. Mazda needs to make either
a. a proper apex seal that can withstand slight overheating/detonation AND last more than 200K or
b. drop a piston motor in the RX-7.

[imaginesix]

I don't get it. I always thought that rotaries were tough as nails. That is one of the benefits that are touted in the Formula Mazda series.
Is this marketing bull? Are there other factors involved that cause them to be reliable (or at least chaep to run) in F Mazda? Maybe they are easy to rebuild, or easy to maintain at equal power levels? (It is a spec series).

[GunStar]

Easy to maintain, easy to rebuild...unless you do something to the front rotor, can take an occasional missed shift, and happily rev all the way to 8000rpm. Most drivers won't kill a rotary without seriously messing up, or really trying to. Missing a upshift is the most common killer of the engine at the racetrack, followed by missing a downshift. After that, not changing the oil between weekends racing is the next big killer.

berge, a rotary is set for a major rebuild between 75,000 to 100,000km. You just ran it a little hotter than normal, and killed 5000km. Your doing good for the people I usually build for. Now, if you mean miles, then you did rippin great. As noted in my first post, they need to update the materials they build the engine with. Even the 13Bs are early to mid 80s metallugy techniques. Just build a new one with todays tech and you'd probably get a reliable 10k rpm and have it run out to 125,000km before a rebuild. May even deal with the thrist and emissions problem. I don't think you can ever quiet those things.

[berge]

Originally posted by GunStar
berge, a rotary is set for a major rebuild between 75,000 to 100,000km. You just ran it a little hotter than normal, and killed 5000km. Your doing good for the people I usually build for. Now, if you mean miles, then you did rippin great. As noted in my first post, they need to update the materials they build the engine with. Even the 13Bs are early to mid 80s metallugy techniques. Just build a new one with todays tech and you'd probably get a reliable 10k rpm and have it run out to 125,000km before a rebuild. May even deal with the thrist and emissions problem. I don't think you can ever quiet those things.

yes, it's Km's.
Agreed about the materials they need to update if they're going to re-introduce a rotary to the market. ESPECIALLY the apex seals!

[ffiloseta]

Mazda has shown the soon the be released RX-8 four door sports car. It sports the RENESIS new generation rotary. See it here:

http://www.howstuffw...naias200122.htm

[ehagar]

Originally posted by GunStar
berge, a rotary is set for a major rebuild between 75,000 to 100,000km.

I guess mine should have expired 60,000 km ago then... it still runs strong.

[int2str]

Check this out... This seems like a raceable rotary (maybe not just F1 yet...). Sorry, page is in german.

http://www.der-wanke...s/mercedes.html

[ffiloseta]

Uh int2str, that's the engine of the MB C111, 31 years old now...

I saw the car in 1971 -impressive !- but after all this years one would think MB dropped any development of its power plant.

[GunStar]

ehagar, treat any engine right and it goes forever. Rotary engines seem to last even better. Less parts to wear out. Hope it lasts another 100,000km.

[AS110]

Funny I should mention the Sachs industrial wankel,a friend came in today and said he unearthed one.It was locked up,but he stipped it,cleaned and put back together,and says it runs like a top.Even though he hasn't got it hooked up to anything,he knows its got way too much power for it's size.Tuff little critter

The Sachs wankel was an oddball atempt at that market.An industrial engine needs to be big,strong and stupid,the Sachs was a sophisticated lightweight,and couldn't hack it in a mans world.I don't work in that field these days,but I notice modern industrial engines have wimpy things like alloy cases and overhead valves.Maybe the wankel should dust off it's paisley tie and flares,the world is starting to catch up.

Oh,and just to round of where wankel engines have been used,they were also put into boats.That just leaves trains,any takers?

[Jhope]

Here's a very interesting link. It may be simple for you lot, but this site helped me understand rotaries a little more.

http://www.mazda-rx7...046&pg_pid=1620

[testarosa]

www.mymazdarotary.com has some nice tech papers on the RENESIS and the 787B rotary engines.
I'd like to see Mazda put a RENESIS in miata, maybe with turbos. That'd be quick...

[Melbourne Park]

Originally posted by testarosa
www.mymazdarotary.com has some nice tech papers on the RENESIS and the 787B rotary engines.
I'd like to see Mazda put a RENESIS in miata, maybe with turbos. That'd be quick...

Mazda have a fleet of rotary Miata/MX5s running in Japan. They are experimental, since they run on hydrogen ...

[MN]

Originally posted by testarosa ..... I'd like to see Mazda put a RENESIS in miata, maybe with turbos. That'd be quick...

It could look something like this. (no, sorry this one only has 1.6-liter il4)