Wankel Rotary Engine - a question for the engineers.

[dugong]

Noise from the former management. Rotary engines are still being developed by enthusiasts. 

Any videos of the new design in action? 

[Junkman]

I remember the Wankel Mazdas at Le Mans in the early Eighties. The noise they made was terrible.

But the noise Billy Hagan's Camaros made was fantastic.

[DSdriver]

I think the daft idea award goes to Citroen for building a wankel engined helicopter.

[worldofceri]

When I was at uni I tried to make a basic 2d moving model of a Wankel motor.  Spent ages plotting the shape of the epitrochoidal combustion chamber in some CAD package or other, only to discover that it was too complicated for the uni's cnc machine to cut out.  Still have the random hopeless bits of ally plate kicking around somewhere.

 

Not sure if I'd already decided I'd make a rubbish engineer by that point.

 

 

Incidentally, the engine in the gif Junkman posted is doing about 72rpm by my reckoning.  It boggles my mind that an actual real life version made out of actual metal can be made to run at tens of thousands of rpm.  As GazzaJ says, it's amazing what looks like it shouldn't work, but does - and vice versa.

[dollywobbler]

 

Incidentally, the engine in the gif Junkman posted is doing about 72rpm by my reckoning.  It boggles my mind that an actual real life version made out of actual metal can be made to run at tens of thousands of rpm.  As GazzaJ says, it's amazing what looks like it shouldn't work, but does - and vice versa.

 

I was thinking exactly that last night. The mind boggles to think of Japanese engines turning over at beyond 10,000rpm. 

[AMC Rebel]

If they want to make fancy engines, can we have mini Deltics in cars please. The only thing that can challenge a V8 for noise (Except for aero engines like Merlins obviously).

 

Since it generates electricity, it should be ideal for the next generation Prius.

[twosmoke300]

10k is playing at it ! look at the revs some of the jap 250 4cyl bikes rev to.

[Bobthebeard]

Are you going foamer apologist on me? I'm no Rotary hater. You know that. 

 

You best tell the Rotary specialists I've spoken to that they're rehashing their facts and figures. 

 

Why did Mazda shelve the RENESIS, then? Why doesn't it have a Rotary halo car now? 

Why are so many RX-8s in scrapyards? 

 

I can't say I'm aware of many LS V8s that need rebuilding after 60,000 miles, either - and yes, SBC swapped FDs of any kind are sacrilege. 

I wasn't aware I was slagging Rotarys [sic] off; they have inherent issues which shorten their lifespan but it doesn't stop them being fabulous (if fragile) lumps.

You're right though, no one buys a Ferrari or Lamborghini for ease of maintenance; it's part and parcel of owning something quick. 

 

Rotarys [sic] ended up as performance engines because the sports car market was the most tolerant of its failings. Mazda tried to sell cooking versions and they bombed - the average owner simply wasn't prepared to put with the histrionics. Remember luckyseven's threads on Retro Rides? His cars were the most pampered things you've ever seen; his FD still failed spectacularly and he still adores them.

I love Rotarys [sic] but I'd never have the financial stones to run one - simply because I couldn't afford the cost of failure when (not if) it occurred. 

Dammit, AS, I tried. I really tried. 

 

I am not plucking these comments out of my arse  -  and it upsets me that you think I'm doing so. As we've discovered on this forum, if I question something, the insults come back ad hominem. That's a very specific message I'm getting.

 

I hear you. I don't have to be here. 

Not insults Jon, just a balanced discussion surely? Don't be upset or offended! No one really doubts your knowledge or experience I suspect.

[Junkman]

I wouldn't mind a go on an Evinrude Wankel snow mobile.

I'd hate the walk back, though.

 

Hence:

 

[cort16]

the main problem with the rotary wankel v v8 debate is with a v8 you don't get to say wankel.

 

wankel

           wankel

                      wankel

                                wankel

                                           wankel

                                wankel

                      wankel

           wankel

wankel

[PhillipM]

The high oil consumption thing is a bit of a myth, yes, they use oil, but it's by design, it's injected into the chambers, so it's a regular loss.

But they still use less than most new BMW/Merc/Audi units burn if you give them a bit of stick. We used to put well over a litre in the BMW buggy every 1000 miles!

[Tamworthbay]

Noise from the former management. Rotary engines are still being developed by enthusiasts. 

Any videos of the new design in action?

 

That sound is just so gorgeous, forget v8, give me that any day.

[twosmoke300]

You reckon ? Am I only the only one who thought that the speaker on my phone had broken when listening to that ?

Flat plane crank v8 = best noise ever ! Closely followed by a big straight 6 turbo diesel

[martc]

The high oil consumption thing is a bit of a myth, yes, they use oil, but it's by design, it's injected into the chambers, so it's a regular loss.

 

But they still use less than most new BMW/Merc/Audi units burn if you give them a bit of stick. We used to put well over a litre in the BMW buggy every 1000 miles!

 

I'm also bemused by the "they use oil" argument - as m'learned friend says they are designed too. No-one complains about 2-strokes using oil.

[Rocket88]

Yep. I'm stoked to see where electric technology takes the car industry. Clean, quiet and can deliver performance unlike almost anything that we have seen before. The Model S is a two ton, quasi-luxury saloon and the new P100D supposedly does 0-60mph in two and half seconds. Only the top end is missing, 154mph top speed but who gives a flying fuck about that when you have just shy of 1000 N-m of torque available from 0RPM?

 

My P100 doesn't..............................

[tooSavvy]

Looks like there are still some very high stress points on ... A$ contributors [again]

 

TS

[Tayne]

The high oil consumption thing is a bit of a myth, yes, they use oil, but it's by design, it's injected into the chambers, so it's a regular loss.

 

But they still use less than most new BMW/Merc/Audi units burn if you give them a bit of stick. We used to put well over a litre in the BMW buggy every 1000 miles!

 

 

 

Well the official line from BMW is that oil consumption of greater than 1 litre per 100 miles means your car is broken.

I'd also add the obvious point that when not ragging your Bavarian wagon it won't drink oil like Oiliver Reed...

 

 

I'm now curious about the oil consumption and longevity of high revving Japanese motorcycle piston engines...

 

And what was the last car (non smokey badger / Mazda Rotary) that had a total loss oil system?

 

 

As a side note, "at least 60k between engine rebuilds" regardless of the engine's size or weight isn't great when these day Ferraris and Lamborghinis come with four year unlimited mileage warranties.

Hell, even Renault gives you 5 years or 100,000miles!

[Dave_Q]

My blade revs to 11500rpm (not that often, admittedly) and doesn't use a drop of oil.

[Guest Hooli]

Mine only revs to 9k, but it is a 1,402cc lump. Doesn't use a drop of oil either & is now on 108k.

[Station]

I did 1000 miles and didn't notice any change in the oil level. It mustn't use a lot.

If you rev to 9000 rpm you get a load of black smoke out of the exhaust, if you watch videos on YouTube of rx7s, the amount of smoke is surprising, I thought mine was broken.

 

You'd have to be hammering it and never changing oil if you get less than 60k miles. Like pistons rings, there is always a film of oil separating the ring and the cylinder wall. Any largish particles in the oil meets the rotor seal at 6000 rpm isn't going to do any good.

[cort16]

The oil consumption may be normal for a rotary engine but the same volume isn't on a piston engine, which is probably why most people who just bought a car thought having to stick a litre in every 600 miles was a bit much.

 

I'm glad they exist and Mazda managed to persuade a lot of people they'd solved some of the  issues with the rx8 but the number of burst ones for sale indicates a fundamental issue when being used daily by a non sympathetic user.

[Tamworthbay]

Well the official line from BMW is that oil consumption of greater than 1 litre per 100 miles means your car is broken.

I'd also add the obvious point that when not ragging your Bavarian wagon it won't drink oil like Oiliver Reed...

 

 

I'm now curious about the oil consumption and longevity of high revving Japanese motorcycle piston engines...

 

And what was the last car (non smokey badger / Mazda Rotary) that had a total loss oil system?

 

 

As a side note, "at least 60k between engine rebuilds" regardless of the engine's size or weight isn't great when these day Ferraris and Lamborghinis come with four year unlimited mileage warranties.

Hell, even Renault gives you 5 years or 100,000miles!

I have had loads of bikes that will redline over 10,000 whilst delivering 120-150bhp/ litre and happily covering a lot of miles. Three have done over 100,000 when in my hands, the VFR was still crisp and tight at 250,000 and pulled like a train. I never needed to top up the oil between services on any of them.

[dollywobbler]

The main issue with the Wankel, especially the Renesis, is that if you get a misfire, you're engine is screwed. The excess unburnt petrol just immediately washes all the oil out and your engine dies. Not ideal. I've been told, by an expert, that if the Check Engine light comes on, you must stop immediately.

That said, he also had plenty of reasons why they're ace!

[Junkman]

Well, my honest verdict from an engineering point of view is that the LiquidPiston engine will work extremely well,

but in typically septic fashion won't last for more than a quarter mile.

 

From a non engineering point of view, I'd have rethought something more important with a $18 million budget.

My retirement plan.

[Junkman]

'Wankel' refers to the NSU/Comotor designs and the latter 'Rotary' belongs solely to Mazda engines. You had licensed Wankels and licensed Rotarys [sic].

 

Actually NSU already referred to it as a Rotary engine, because that's what the 'Ro' in Ro80 stands for.

[dugong]

Actually NSU already referred to it as a Rotary engine, because that's what the 'Ro' in Ro80 stands for.

 

That.....................

 

Is a fair point. Mazda trademarked 'Rotary' (and NSU never made any more so, er......). I'll have to dig that Comotor brochure out which calls its engines 'Wankels' throughout. 

 

Mazda's corporate history makes a big song and dance about how it licensed the Wankel from NSU and then transformed it into the Rotary.  

[robinmasters]

It built a rough prototype nicknamed the 'Smokey Badger'

 

Surely I can't be only one who thinks that like an absolutely filthy euphemism? 'That's right Sharon, I have him a Smokey Badger and he tore up the pre-nuptial agreement and agreed to spend Christmas with my sister'.

 

Since it generates electricity, it should be ideal for the next generation Prius.

 

Which brings us conveniently back to Deltics. Why aren't diesel-electric cars 'a thing' (as I believe they say in contemporary parlance)?

 

My P100 doesn't..............................

Re-read the post you're replying to, pur-lease. It said P100D. Is yours a diesel? Thought not. A 1.8d P100 will do 0-60 quicker than a fast motorbike, I thought everyone knew that.

 

From a non engineering point of view, I'd have rethought something more important with a $18 million budget.

My retirement plan.

Cost of subcontracting IT person to produce gif: $100

Retirement fund: $17,999,900

 

I like to think I have a basic grasp of how an internal combustion engine works, which most people don't. But I still struggle with wankels; why don't all the petrol fall out the side of that weird turny-round bit? (I do understand why, but there's a Matthew Hopkins part of my brain which says it shouldn't, therefore it's wrong and be chased out of the village with pitchforks).

[Junkman]

That.....................

 

Is a fair point. Mazda trademarked 'Rotary' (and NSU never made any more so, er......). I'll have to dig that Comotor brochure out which calls its engines 'Wankels' throughout. 

 

Mazda's corporate history makes a big song and dance about how it licensed the Wankel from NSU and then transformed it into the Rotary.  

 

 

NSU was always very relaxed when it came to trademarks and licencing.

Don't forget, they allowed a Fiat licencee to use their name (NSU-Fiat) for decades, just because he built cars in a factory once owned by NSU and NSU not making any cars at the time,

only motorcycles. Only when they took up car production themselves in the 50s, they objected.

 

Also don't forget, that they did the Wankel in the 60s, what with all that psychedelic shit and free sex and we're going to the Moon and build a supersonic passenger aeroplane

and travel to England on an SR.N4 just because we can.

 

I don't even want to know what the paper trail of the original Wankel licence looks like.

[Rover414]

I fell in love with the rotary engine not long after I got my first RX8. It was just so smooth and effortless to get up to the top end that it seemed like nothing else I'd driven before. As for the rebuilding process, my blue R3 is just shy of 73k without one, has a good compression result fairly recently, although I am aware they made some modifications for the Series 2 engines.

[PhillipM]

Well the official line from BMW is that oil consumption of greater than 1 litre per 100 miles means your car is broken.

I'd also add the obvious point that when not ragging your Bavarian wagon it won't drink oil like Oiliver Reed...

 

 

I'm now curious about the oil consumption and longevity of high revving Japanese motorcycle piston engines...

 

And what was the last car (non smokey badger / Mazda Rotary) that had a total loss oil system?

There are a lot of modern cars that will use 0.5-1L per 1000 miles, technically I suppose they are total loss because they're deliberately designed to use some oil at high rpm by use of tighter fits with better scrapers but lower tension rings, etc, to get better economy and emissions at low rpm for testing.

 The downside is the scrapers are too effective for good higher rpm lubrication with the tighter clearances, so they deliberately taper the rings so they'll float over the oil at higher piston speeds to keep the walls from scuffing.

 As a side note the rotary will also use less oil when just running around because the injection rate is tied to rpm and throttle position - the BMW used more oil than the rotary did when we had 'em!